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Associate Professor Andrew McDonagh

Biography

Andrew McDonagh received his PhD from the Australian National University in 1999 for work investigating the nonlinear optical properties of some transition metal acetylide complexes. He then took up a post-doctoral research position at the University of Bristol, UK. He was awarded a UNSW Vice-chancellor's Post-doctoral Research Fellowship at the University of New South Wales in 2001 and was made lecturer in 2002. He joined UTS in 2003 as a lecturer in chemistry. He is currently an ARC Post-doctoral Research Fellow.

He has expertise in the design and synthesis of functional molecules together with experience in the construction of micro- and nanoscale devices. His projects involve the design and synthesis of light-harvesting ruthenium-based dyes, nanoparticles for forensic fingermark detection, light-responsive molecular structures, molecules for electrochemical switching of nonlinear optical properties, and new types of self-assembled monolayers.

Image of Andrew McDonagh
Associate Head of School (Teaching and Learning), School of Mathematical and Physical Sciences
Member, Research Centre for Clean Energy Technology
Associate Member, CFS - Centre for Forensic Science
Core Member, CCET - Centre for Clean Energy Technology
BSc (Hons) (ANU), PhD Philosphy (ANU)
Member, Royal Australian Chemical Institute
 
Phone
+61 2 9514 1035
Can supervise: Yes

Chapters

El Saliby, I., Shon, H. & McDonagh, A.M. 2013, 'Visible-light active doped titania for water purification: nitrogen and silver doping' in Lens, P.N.L., Virkutyte, J., Jegatheesan, V., Kim, S.H. & Al-Abed, S. (eds), Nanotechnology for Water and Wastewater Treatment, IWA Publishing, London, UK, pp. 189-208.
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Photocatalysis over semiconductors, mainly Ti02, has been employed and extensively studied over the past few decades (Malato et aI., 2009). The so-called "first generation photocatalYSIS" are characterised by their photoexcitation limited to the UV region of the solar spectrum. Nevertheless, many photocatalysts showed outstanding performance in decomposing a large number of pollutants of water and air. A number of water pollutants belong to the family of biorecalcitrant pollutants (non-biodegradable) and these include pharmaceutical and personal care products, industrial wastes, and a large number of pesticides/herbicides. Many of the emerging pollutants are resistant to conventional water treatment processes, noxious to the environment and some are classified as endoctine disrupting agents. The removal of non-biodegradable pollutants from wastewater poses a serious challenge for the water industry. Generally, advanced oxidation processes (AOP) are employed to achieve this goal. Heterogeneous photocatalysis, as part of AOP, is sometimes adopted as a tool to eliminate these contaminants. However, the high cost associated with the use of photocatalysis to treat such compounds has always been a disadvantage for its large-scale adoption in treatment processes. The high cost is mainly associated with: (1) the energy consumed for the UV light irradiation of the photocatalyst, (2) the energy required for the separation of the photocatalyst particles from water. A total of 40% of the solar light reaching the lithosphere is visible light, whereas UV light accounts only for 5% of the total solar radiation. The development of new photocatalysts that can effectively harvest visible light is crucial for making this technology viable in the waler treatment industry. The use of "second-generation riOz photocatalysts" to harvest visible light from solar energy is gaining popularity (Anpo, 1997). Most of the research involving the use of second generation TiOz photocatalysts has...
Cortie, M.B. & McDonagh, A.M. 2009, 'Nanoscience of gold and gold surfaces' in Mohr, F. (ed), gold chemistry: applications and future directions in the life sciences, Wiley-VCH, Weinheim, pp. 321-355.
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Conferences

Shahcheraghi, N., Dowd, A., McDonagh, A., Cortie, M.B. & Keast, V. 2014, 'Multimode plasmon resonances on double- and triple-decker stacks of silver nanotriangles', 2014 International Conference on Nanoscience and Nanotechnology, IEEE, pp. 57-60.
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Nanotriangles of silver may be readily synthesized by wet chemical techniques and exhibit a strong localized surface plasmon resonance with light. Here we examine the complex resonances of nanotriangles in double-and triple-decker sandwich configurations.
Canning, J., Ma, M., Gibson, B., Huyang, G., Beavis, A., Bishop, D., Cook, K., McDonagh, A., Shi, J., Shi, D., Peng, G.-.D. & Crossley, M. 2013, 'The nanostructure of silica microfibers fabricated by microfluidic self-assembly', FOURTH ASIA PACIFIC OPTICAL SENSORS CONFERENCE.
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Huyang, G., Canning, J., Bishop, D., McDonagh, A. & Crossley, M.J. 2012, 'An evaluation of the distribution of metal ions in otherwise uniform titania sol-gel layers designed for optical sensing using laser ablation inductive coupled plasma mass spectroscopy', Proceedings of SPIE - The International Society for Optical Engineering.
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Free-base porphyrins are bound to titania sol-gel layers deposited on glass slides. The porphyrin-containing titania layers show the UV-VIS spectra of the porphyrin and are found to be uniformly and evenly distributed. By addition of a metal salt to the titania layer, it was possible to metallate the free-base porphyrin within and change the UV-VIS absorbance of the porphyrin. The metalloporphyrins based on Cu and Zn ions could be detected by laser ablation inductive coupled plasma mass spectroscopy (LA-ICP-MS). Aggregation of metals is observed indicating that metal ions are also attaching directly to the titania. In samples where already metalized porphyrins are used little or no aggregation is observed, indicating that the titania sol gel is non-uniform in its affinity for metal ions. © 2012 SPIE.
Zareie, H.M., Sarikaya, M., McDonagh, A.M., Barber, J., Cortie, M.B. & Phillips, M. 2007, 'Self-organised materials: from organic molecules to genetically engineered gold-binding proteins', 2006 International Conference on Nanoscience and Nanotechnology, ICONN, IEEE, Brisbane, Australia, pp. 517-519.
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We present examples of ordered assemblies of organic and biological molecules on gold(111) surfaces. The first example shows how control over mono or multilayer assemblies of 1,4-phenylenedimethanthiol can be achieved and monitored. The second example shows how monolayers on gold can be prepared using amine groups to anchor aromatic molecules to the surface. A third example whos how ordered assemblies of genetically-engineered inorganic-binding polypeptides can be formed on gold surfaces using a 3-repeat, 14 amino acid gold-binding protein (GBP1).
Ford, M., Hoft, R.C., Gale, J.D. & McDonagh, A.M. 2007, 'A new class of self-assembled monolayers on gold using an alkynyl group as linker', Proceedings of the 2006 International Conference on Nanoscience and Nanotechnology, ICONN, IEEE, Brisbane QLD, Australia, pp. 645-648.
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The geometry and energetics for adsorption of ethynylbenzene on au(!!!) have been studied using Density Functional Theory. The alkynyl group, following removal of the terminal H atom, adsorbs covalently to the surface in the fcc hollow site with a bond energy of about 70 kcal.mol-1. Intermediate adsorption states are also possible via a hydrogen 1,2 shoft to form a surface-bound vinylidene, or through the opening o the c-c triple bond without removing the hydrogen atom.
Asselberghs, I., McDonagh, A.M., Ward, M.D., McCleverty, J.A., Coe, B., Persoons, A. & Clays, K. 2005, 'Switching of the first hyperpolarisability', SPIE Proceedings, Int. Soc. Opt. Eng 5935 (Linear and Nonlinear Optics of Organic Materials V), Linear and Nonlinear Optics of Organic Materials V, SPIE Proceedings, Int. Soc. Opt. Eng, USA, pp. 215-223.
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Second-order nonlinear optical properties of organic and inorganic materials have been widely investigated. However, it becomes more important to be able to switch the molecules from an 'on' state to an 'off' state, or vise versa. Several switching schemes can be thought of. We will focus our attention to alter the donor properties of metalorganic compounds. Therefore, we will oxidize the metal center of the compound chemically. Since it is more interesting to be able to electrochemically switch the metal center, we developed a combined electrochemistry/hyper-Rayleigh scattering cell to perform in-situ electrochemical switching of the hyper-Rayleigh response
Samoc, M., Humphrey, M.G., Cifuentes, M.P., McDonagh, A.M., Powell, C.E., Heath, G.A. & Luther-Davies, B. 2001, 'Third-order optical nonlinearities of organometallics: Influence of dendritic geometry on the nonlinear properties and electrochromic switching of nonlinear absorption', Proceedings of SPIE - The International Society for Optical Engineering, pp. 65-77.
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We have investigated a large number of organometallic structures possessing high second and third order optical nonlinearities. Most third-order NLO experiments were performed with 100 femtosecond light pulses at 800 nm. While investigating structure-property relationships we note an enhancement of the real and imaginary parts of the cubic hyperpolarizability in structures of trigonal symmetries, and, in particular, of dendritic geometries with multipolar charge distribution, due to the presence of charge acceptor groups. Two-photon absorption cross sections achievable in these structures are comparable with the best values reported in the literature. We also show that, for some of the ruthenium alkynyl complexes investigated in this study, it is possible to perform electrochemical switching between two forms of the compound. The nonlinear properties of the two forms were investigated by the technique of Z-scan carried out in situ in an electrochemical cell. The neutral form is essentially nonabsorbing in the infrared but shows two-photon absorption at 800 nm. Upon oxidation the complex becomes infrared absorbing and the oxidized form exhibits an absorption saturation effect at 800 nm. This electrochromic switching of both the linear absorption and the sign of the imaginary part of the third-order susceptibility is found to be reversible and is, therefore, of potential application interest.
Cowin, M.A., Varrazza, R., Morgan, C., Penty, R.V., White, I.H., McDonagh, A.M., Bayly, S., Riley, J., Ward, M.D. & McCleverty, J.A. 2001, 'Low power electrochromic variable optical attenuator with 50dB attenuation range', Conference on Optical Fiber Communication, Technical Digest Series.
A variable optical attenuator based upon a new molybdenum electrochromic compound is described. The device exhibits an attenuation range of >50dB at 1310nm, for a drive power of 150W, and an insertion loss of 1.5dB.

Journal articles

Su, D., McDonagh, A., Qiao, S.-.Z. & Wang, G. 2017, 'High-Capacity Aqueous Potassium-Ion Batteries for Large-Scale Energy Storage.', Adv Mater, vol. 29, no. 1.
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A potassium iron (II) hexacyanoferrate nanocube cathode material is reported, which operates with an aqueous electrolyte to deliver exceptionally high capacities (up to 120 mA h g(-1) ). The cathode material exhibits excellent structural integrity, leading to fast kinetics and highly reversible properties. All of the battery materials are safe, inexpensive, and provide superior high-rate, long-cycle-life electrochemical performance.
Heather, E., Bortz, A., Shimmon, R. & McDonagh, A.M. 2017, 'Organic impurity profiling of methylone and intermediate compounds synthesized from catechol.', Drug Test Anal, vol. 9, no. 3, pp. 436-445.
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This work examined the synthesis and organic impurity profile of methylone prepared from catechol. The primary aim of this work was to determine whether the synthetic pathway used to prepare 3,4-methylenedioxypropiophenone could be ascertained through analysis of the synthesized methylone. The secondary aim was the structural elucidation and origin determination of the organic impurities detected in methylone and the intermediate compounds. The organic impurities present in the reaction products were identified using GC-MS and NMR spectroscopy. Six organic impurities were detected in 1,3-benzodioxole and identified as the 1,3-benzodioxole dimer, 1,3-benzodioxole trimer, [1,3] dioxolo[4,5-b]oxanthrene, 4,4'-, 4,5'-, and 5,5'-methylenebis-1,3-benzodioxole. Six organic impurities were detected in 3,4-methylenedioxypropiophenone and identified as (2-hydroxyphenyl) propanoate, [2-(chloromethoxy) phenyl] propanoate, (2-propanoyloxyphenyl)propanoate, 5-[1-(1,3-benzodioxol-5-yl)prop-1-enyl]-1,3-benzodioxole, (5E)- and (5Z)-7-(1,3-benzodioxol-5-yl)-5-ethylidene-6-methyl-cyclopenta[f][1,3]benzodioxole). Exploratory synthetic experiments were also conducted to unambiguously identify the organic impurities detected in 3,4-methylenedioxypropiophenone. Two organic impurities were detected in 5-bromo-3,4-methylenedioxypropiophenone and identified as [2-(chloromethoxy)phenyl] propanoate and 3,4-methylenedioxypropiophenone. Five organic impurities were detected in methylone and identified as 3,4-methylenedioxypropiophenone, 1-(1,3-benzodioxol-5-yl)-N-methyl-propan-1-imine, 1-(1,3-benzodioxol-5-yl)-2-methylimino-propan-1-one, 1-(1,3-benzodioxol-5-yl)-N1,N2-dimethyl-propane-1,2-diimine and butylated hydroxytoluene. The origin of these organic impurities was also ascertained, providing valuable insight into the chemical profiles of methylone and the intermediate compounds. However, neither the catechol precursor nor the 1,3-benzodioxole intermediate could be identified based on the ...
Zhang, J., Sun, B., McDonagh, A.M., Zhao, Y., Kretschmer, K., Guo, X. & Wang, G. 2017, 'A multi-functional gel co-polymer bridging liquid electrolyte and solid cathode nanoparticles: An efficient route to Li–O2 batteries with improved performance', Energy Storage Materials, vol. 7, pp. 1-7.
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© 2016Lithium-oxygen (Li–O2) batteries have the highest theoretical energy density amongst all rechargeable batteries and have attracted significant attention. However, large over-potentials originating from sluggish reaction kinetics often lead to low round-trip energy efficiency and short cycle life. We report here a novel multi-functional gel co-polymer that efficiently enhances the discharge and charge performances in Li–O2 batteries by intimately connecting the liquid electrolyte and solid cathode nanoparticles. On one hand, the co-polymer material, poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate-co-methyl methacrylate) (P(TMA-MMA)), functions as a binder during the fabrication of the cathode and forms a gel polymer membrane to retain liquid electrolyte and to increase ionic conductivity. On the other hand, the TMA units, containing N–O radical groups that catalyse Li2O2 formation and decomposition during charge and discharge cycles, are distributed throughout the polymer membrane. This allows more effective formation and decomposition of Li2O2 than surface bound catalytic units. The combination of gelable MMA and catalytic TMA moieties enhances the interface between liquid electrolyte and solid cathode by functioning as a medium both to transport Li+ (enhancing discharge process) and to carry electrons (reducing charge over-potential). Consequently, the optimized P(TMA-MMA) co-polymers provide exceptional electrochemical performance in Li–O2 batteries.
Tam, R., Heather, E., Shimmon, R., Lam, B. & McDonagh, A.M. 2017, 'Synthesis and organic impurity profiling of 4-methoxymethamphetamine hydrochloride and its precursors.', Forensic Sci Int, vol. 272, pp. 184-189.
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4-Methoxymethamphetamine (PMMA) was synthesised from star anise and from 4-methoxytoluene and the organic impurity profiles examined. These two starting materials are unrestricted chemicals in many jurisdictions and contain the requisite functional groups and are thus well suited for clandestine manufacturers. trans-Anethole was extracted from star anise and oxidised to 4-methoxyphenyl-2-propanone (PMP2P). 4-Methoxytoluene was oxidised to anisaldehyde, converted to 4-methoxyphenyl-2-nitropropene, and then reduced to PMP2P. The PMP2P obtained by both methods was then converted to PMMA via the Leuckart reaction. 4-Methoxymethamphetamine hydrochloride (PMMAHCl) was synthesised from PMMA using hydrogen chloride gas. Both of the examined synthetic methods were found to be feasible routes into PMMAHCl. The products of each step were analysed by gas chromatography-mass spectrometry (GC-MS) and proton nuclear magnetic resonance spectroscopy ((1)H NMR). Impurities were examined in an attempt to identify route specific compounds, which may provide valuable information about the synthetic pathway and precursors.
Scott, J.A., Totonjian, D., Martin, A.A., Tran, T.T., Fang, J., Toth, M., McDonagh, A.M., Aharonovich, I. & Lobo, C.J. 2016, 'Versatile method for template-free synthesis of single crystalline metal and metal alloy nanowires.', Nanoscale, vol. 8, no. 5, pp. 2804-2810.
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Metal and metal alloy nanowires have applications ranging from spintronics to drug delivery, but high quality, high density single crystalline materials have been surprisingly difficult to fabricate. Here we report a versatile, template-free, self-assembly method for fabrication of single crystalline metal and metal alloy nanowires (Co, Ni, NiCo, CoFe, and NiFe) by reduction of metal nitride precursors formed in situ by reaction of metal salts with a nitrogen source. Thiol reduction of the metal nitrides to the metallic phase at 550-600 °C results in nanowire growth. In this process, sulfur acts as a uniaxial structure-directing agent, passivating the surface of the growing nanowires and preventing radial growth. The versatility of the method is demonstrated by achieving nanowire growth from gas-phase, solution-phase or a combination of gas- and solution-phase precursors. The fabrication method is suited to large-area CVD on a wide range of solid substrates.
Sornalingam, K., McDonagh, A. & Zhou, J.L. 2016, 'Photodegradation of estrogenic endocrine disrupting steroidal hormones in aqueous systems: Progress and future challenges.', Sci Total Environ, vol. 550, pp. 209-224.
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This article reviews different photodegradation technologies used for the removal of four endocrine disrupting chemicals (EDCs): estrone (E1), 17-estradiol (E2), estriol (E3) and 17-ethinylestradiol (EE2). The degradation efficiency is greater under UV than visible light; and increases with light intensity up to when mass transfer becomes the rate limiting step. Substantial rates are observed in the environmentally relevant range of pH7-8, though higher rates are obtained for pH above the pKa (~10.4) of the EDCs. The effects of dissolved organic matter (DOM) on EDC photodegradation are complex with both positive and negative impacts being reported. TiO2 remains the best catalyst due to its superior activity, chemical and photo stability, cheap commercial availability, capacity to function at ambient conditions and low toxicity. The optimum TiO2 loading is 0.05-1gl(-1), while higher loadings have negative impact on EDC removal. The suspended catalysts prove to be more efficient in photocatalysis compared to the immobilised catalysts, while the latter are considered more suitable for commercial scale applications. Photodegradation mostly follows 1st or pseudo 1st order kinetics. Photodegradation typically eradicates or moderates estrogenic activity, though some intermediates are found to exhibit higher estrogenicity than the parent EDCs; the persistence of estrogenic activity is mainly attributed to the presence of the phenolic moiety in intermediates.
Shahid, M., Tijing, L.D., El Saliby, I., McDonagh, A., Kim, J.B., Kim, J.H. & Shon, H.K. 2016, 'Adsorption behavior of Pb(II) onto potassium polytitanate nanofibres', Journal of Nanoscience and Nanotechnology, vol. 16, no. 2, pp. 1916-1919.
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Copyright © 2016 American Scientific Publishers All rights reserved.Potassium polytitanate nanofibres prepared by a hydrothermal method were investigated for their possible application in removing toxic metals from aqueous solution. Particular attention was paid to employing the titanate as a novel effective adsorbent for the removal of Pb(II). Batch adsorption experiments demonstrated that the adsorption was influenced by various conditions such as solution pH, adsorbent dosage and initial Pb(II) concentration. The results showed that the adsorption rate was faster in the first 5 min and equilibrium was achieved after 180 min. The maximum amount of adsorption was detected at pH 5. Potassium titanate showed much higher adsorption capacity compared to P25. The kinetic studies indicated that the adsorption of Pb(II) onto titanate best fit the pseudo-second-order kinetic model. FTIR spectra revealed that the hydroxyl groups in titanate were responsible for Pb(II) adsorption. The principal mechanism of the adsorption of Pb(II) in the present study is attributed to both ion exchange and oxygen bonding. The adsorption-desorption results demonstrated that the titanate could be readily regenerated after adsorption. Therefore, the present titanate exhibits great potential for the removal of Pb(II) from wastewater.
Angeloski, A., Baker, A.T., Bhadbhade, M. & McDonagh, A.M. 2016, 'Bis(2S,S-di(isopropyl)dithiocarbamato)nickel(II): Anagostic C–HNi interactions and physical properties', Journal of Molecular Structure, vol. 1113, pp. 127-132.
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Abstract The molecular structure of bis(2S,S-di(isopropyl)dithiocarbamato)nickel(II) has been examined by single crystal X-ray diffraction. The data reveal a C–HNi anagostic interaction arising from the interaction of two non-equivalent molecules within the crystal. Thermal analysis data show that the complex decomposes at 330 °C. The structure of the resultant NiS material was examined using scanning electron microscopy and energy dispersive X-ray spectroscopy which revealed NiS nanowires.
Moezzi, A., Cortie, M. & McDonagh, A. 2016, 'Transformation of zinc hydroxide chloride monohydrate to crystalline zinc oxide', DALTON TRANSACTIONS, vol. 45, no. 17, pp. 7385-7390.
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King, S.R., Shimmon, S., Gentle, A.R., Westerhausen, M.T., Dowd, A. & McDonagh, A.M. 2016, 'Remarkable thermal stability of gold nanoparticles functionalised with ruthenium phthalocyanine complexes.', Nanotechnology, vol. 27, no. 21, p. 215702.
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A gold nanoparticle (AuNP) ruthenium phthalocyanine (RuPc) nanocomposite has been synthesised that exhibits high thermal stability. Electrical resistance measurements revealed that the nanocomposite is stable up to 320 °C. Examination of the nanocomposite and the RuPc stabiliser complex using thermogravimetric analysis and differential scanning calorimetry show that the remarkable thermal stability is due to the RuPc molecules, which provide an effective barrier to sintering of the AuNPs.
Shahid, M., El Saliby, I., McDonagh, A., Chekli, L., Tijing, L., Kim, J.H. & Shon, H. 2016, 'Adsorption and Photocatalytic Degradation of Methylene Blue Using Potassium Polytitanate and Solar Simulator', Journal of Nanoscience and Nanotechnology, vol. 16, pp. 4342-4349.
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Solar photocatalytic degradation of organic water pollutants can be used to degrade toxic organic pollutants in water. In this study, potassium titanate nanofibres were synthesized by an aqueous peroxide route at high pH and examined as photocatalysts for photodegradation of methylene blue (MB) using a solar simulator. Initially, MB was adsorbed on the surface of potassium polytitanates to achieve adsorption equilibrium before the photocatalysts were illuminated using solar simulator. The results showed that potassium polytitanate nanofibres were effective adsorbents of MB and also facilitated its photocatalytic degradation. Sulphate ion evolution during photocatalysis confirmed that some mineralisation occurred and hence photo-oxidative degradation of MB took place. The optimum operational conditions for the photocatalytic degradation of MB were found at 0.05 g/L of photocatalyst load, 10 mg/L MB and pH 7. The stability and regeneration of the photocatalyst specimen was also studied for 3 degradation cycles using adsorption/photocatalysis model. Morphological structure analysis of potassium titanate showed nanocrystallines structure of longitudinally-oriented isolated fibre with a length up to several micrometres with diameters ranging from 10 to 20 nanometres.
Angeloski, A., Hook, J., Bhadbhade, M., Baker, A.T. & McDonagh, A.M. 2016, 'Intramolecular HS interactions in metal di-(isopropyl)dithiocarbamate complexes', CrystEngComm, vol. 18, no. 37, pp. 7070-7077.
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Networks of C–HS interactions have been discovered within the molecular structure of sodium di-(isopropyl)dithiocarbamate pentahydrate with the formula Na(C7H14NS2)5H2O, revealed by single crystal X-ray diffraction. These interactions have also been investigated by ab initio and Hirshfeld surface analyses which show that the electron density is not symmetrical about the molecule. NMR spectroscopy in solution and solid the state showed temperature dependent restricted rotation of the isopropyl groups, which is attributed to the intramolecular C–HS interactions. The ubiquitous nature of C–HS intramolecular interactions in this class of compound is evident in the structures of other di-(isopropyl)dithiocarbamate complexes deposited in the CSD. In general, the restricted rotation in di-(isopropyl)dithiocarbamate complexes can be directly attributed to intramolecular C–HS interactions, which subsequently influence the geometry in association with steric repulsion factors.
Shahid, M., Saliby, I.E., Tijing, L.D., McDonagh, A., Park, S.M., Lee, K.Y., Shon, H.K. & Kim, J. 2015, 'Synthesis and Characterisation of Silica-Modified Titania for Photocatalytic Decolouration of Crystal Violet', Journal of Nanoscience and Nanotechnology, vol. 15, no. 7, pp. 5326-5329.
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In the past few years, silica-modified titania has drawn increasing attention due to their special properties making them ideal candidates for a wide range of applications. In this study, we report a novel method for the synthesis of silica-modified titania by a sol–gel method using sodium silicate solution (1 M). The hydrolysis and condensation reactions of titanium dioxide (TiO2, Degussa Aeroxide® P25) in sodium silicate solution proceeded with citric acid (3 M) as a catalyst. The orbital shaking method was followed for the removal of sodium salt formed during the sol–gel process. Solvent exchange was carried out using methanol and hexane. Finally, chemical modification of the gel was conducted using trimethylchlorosilane followed by ambient pressure drying. The obtained silica-modified titania was characterised for nanostructural analysis using scanning electron microscopy and transmission electron microscopy. The nitrogen adsorption–desorption measurements were employed to investigate the BET surface area, pore structure and pore volume of specimens. Thermal gravimetric analysis showed exothermic peaks at temperature range of 90–190 °C representing the oxidation of organic groups from –Si–R network. The silica-modified titania showed high photocatalytic activity and an easy recovery using crystal violet as model water pollutant.
Katz, A., McDonagh, A., Tijing, L. & Shon, H.K. 2015, 'Fouling and inactivation of titanium dioxide-based photocatalytic systems', Critical Reviews in Environmental Science and Technology, vol. 45, no. 17, pp. 1880-1915.
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Titanium dioxide is an effective photocatalyst for the breakdown of many environmental contaminants. The complex mixtures that can occur in water matrices can significantly affect the breakdown of the contaminants in water by titanium dioxide (TiO<inf>2</inf>). The authors discuss a wide variety of foulants and inhibitors of photocatalytic TiO<inf>2</inf> systems and review different methods that can be effective for their fouling prevention. Approaches to regenerate a fouled or contaminated TiO<inf>2</inf> catalysts are explored and the effect of substrates on immobilized titanium dioxide is also reviewed.
Heather, E., Shimmon, R. & McDonagh, A.M. 2015, 'Organic impurity profiling of 3,4-methylenedioxymethamphetamine (MDMA) synthesised from catechol', FORENSIC SCIENCE INTERNATIONAL, vol. 248, pp. 140-147.
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Shahid, M., McDonagh, A., Kim, J.H. & Shon, H.K. 2015, 'Magnetised titanium dioxide (TiO2) for water purification: preparation, characterisation and application', Desalination and Water Treatment, vol. 54, no. 4-5, pp. 979-1002.
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&copy; 2014 Balaban Desalination Publications. All rights reserved. The study of titanium dioxide (TiO2) as a photocatalyst for water purification has attracted significant attention over the past four decades. However, the separation of photocatalyst from water suspension may be difficult, costly and jeopardise the use of this water treatment technology. Recently, the development and production of magnetised TiO2 have been achieved to offer a solution for the photocatalyst separation problem. This paper discusses the preparation techniques, characterisation and the applications of magnetised TiO2. Many researchers have studied magnetised TiO2 photocatalysts but the lack of articles discussing the water purification processes is still slowing any advance in this field. Here, the progress of the scientific research on preparation techniques to coat magnetic particles by materials such as organic polymers, silica, magnesia, and alumina are reviewed to compare and discuss recent findings. The doping of photoactive TiO2 photocatalyst into the magnetic-coated particles is also emphasised. In addition, the characterisation of magnetised TiO2 in terms of physicochemical properties and operating conditions produced by each technique are critically reviewed. Moreover, examples of applications of TiO2 and magnetised TiO2 photocatalyst in water purification are summarised. In general, the effectiveness of organic removal by magnetised TiO2 is still lower compared to single phase TiO2. The future prospect of this field is deliberated to develop a novel, economic and efficient magnetised TiO2 photocatalyst, which has high organic removal properties.
King, S.R., Massicot, J. & McDonagh, A.M. 2015, 'A straightforward route to tetrachloroauric acid from gold metal and molecular chlorine for nanoparticle synthesis', Metals, vol. 5, no. 3, pp. 1454-1461.
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&copy; 2015 by the authors; licensee MDPI, Basel, Switzerland.Aqueous solutions of tetrachloroauric acid of high purity and stability were synthesised using the known reaction of gold metal with chlorine gas. The straightforward procedure developed here allows the resulting solution to be used directly for gold nanoparticle synthesis. The procedure involves bubbling chlorine gas through pure water containing a pellet of gold. The reaction is quantitative and progressed at a satisfactory rate at 50 &deg;C. The gold(III) chloride solutions produced by this method show no evidence of returning to metallic gold over at least twelve months. This procedure also provides a straightforward method to determine the concentration of the resulting solution using the initial mass of gold and volume of water.
El Saliby, I., McDonagh, A.M. & Shon, H. 2014, 'Co-doped mesoporous titania photocatalysts prepared from a peroxo-titanium complex solution', Materials Research Bulletin, vol. 49, pp. 7-13.
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Shahid, M., El Saliby, I., McDonagh, A.M., Kim, J.H. & Shon, H. 2014, 'Photodesorption of specific organic compounds from titanium dioxide particles in aqueous media', Desalination and Water Treatment, vol. 52, no. 4-6, pp. 867-872.
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This study investigates the photodesorption of organic compounds (beef extract, peptone, humic acid, tannic acid, sodium lignin sulphonate, sodium lauryl sulphate, arabic gum powder and arabic acid) from TiO2 (1g/L in water, pH 7). After a period to reach adsorption equilibrium, photodesorption experiments were conducted in a recirculated reactor at a constant flow rate of 150mL/min with a UV light intensity of 24W. Photodesorption was observed only for sodium lauryl sulphate (50%), sodium lignin sulphonate (43.47%), beef extract (20.35%) and tannic acid (10.5%) indicating that photodesorption is specific to some organic compounds but not to all. Using liquid chromatography-organic carbon detection, untreated beef extract and sodium lignin sulphonate were found to contain significant amounts of humic substances (1,000g/mol), which decreased in concentration after dark phase adsorption, while a significant increase in low molecular weight (<350g/mol) concentrations was observed after photodesorption. UV-treated sodium lauryl sulphate photodesorbed to give both higher molecular weight (HMW) and lower molecular weight (LMW) organics. Thus, the HMW fractions of organic compounds decomposed into smaller compounds after UV irradiation, which subsequently desorbed from TiO2 surface. However, untreated tannic acid contained a larger proportion of LMW acids, which shows a high adsorption affinity to TiO2 during adsorption and poorly desorbs upon irradiation.
Shon, H., Shahid, M. & McDonagh, A.M. 2014, 'Magnetised titanium dioxide (TiO2) for water purification: preparation, characterisation, and application', Desalination and Water Treatment, vol. 266.
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Coutts, M.J., Zareie, H.M., Cortie, M.B. & McDonagh, A.M. 2014, 'Charging of gold/metal oxide/gold nanocapacitors in a scanning electron microscope', NANOTECHNOLOGY, vol. 25, no. 15.
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Moezzi, A., Cortie, M., Dowd, A. & McDonagh, A. 2014, 'On the formation of nanocrystalline active zinc oxide from zinc hydroxide carbonate', JOURNAL OF NANOPARTICLE RESEARCH, vol. 16, no. 4.
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Shahid, M., El Saliby, I., McDonagh, A., Tijing, L.D., Kim, J. & Shon, H.K. 2014, 'Synthesis and characterisation of potassium polytitanate for photocatalytic degradation of crystal violet', Journal of Environmental Sciences, vol. 26, no. 11, pp. 2348-2354.
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Canning, J., Huyang, G., Ma, M., Beavis, A., Bishop, D., Cook, K., McDonagh, A., Shi, D., Peng, G.-.D. & Crossley, M.J. 2014, 'Percolation diffusion into self-assembled mesoporous silica microfibres', Nanomaterials, vol. 4, no. 1, pp. 157-174.
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Percolation diffusion into long (11.5 cm) self-assembled, ordered mesoporous microfibres is studied using optical transmission and laser ablation inductive coupled mass spectrometry (LA-ICP-MS). Optical transmission based diffusion studies reveal rapid penetration (< 5 s, D > 80 um2.s-1) of Rhodamine B with very little percolation of larger molecules such as zinc tetraphenylporphyrin (ZnTPP) observed under similar loading conditions. The failure of ZnTPP to enter the microfibre was confirmed, in higher resolution, using LA-ICP-MS. In the latter case, LA-ICP-MS was used to determine the diffusion of zinc acetate dihydrate, D ~ 3 x 10-4 nm2.s-1. The large differences between the molecules are accounted for by proposing ordered solvent and structure assisted accelerated diffusion of the Rhodamine B based on its hydrophilicity relative to the zinc compounds. The broader implications and applications for filtration, molecular sieves and a range of devices and uses are described.
Cortie, M.B., Coutts, M.J., Ton-That, C., Dowd, A.R., Keast, V. & McDonagh, A.M. 2013, 'On The Coalescence Of Nanoparticulate Gold Sinter Ink', Journal Of Physical Chemistry C, vol. 117, no. 21, pp. 11377-11384.
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We examine the mechanism by which thiol-protected gold nanoparticle inks can sinter at surprisingly low temperatures. At room temperature the sample is comprised of randomly close-packed gold nanoparticles of about 2.3 nm diameter with a ligand shell of
Moezzi, A., Cortie, M.B. & McDonagh, A.M. 2013, 'Formation Of Zinc Hydroxide Nitrate By H+-catalyzed Dissolution-precipitation', European Journal Of Inorganic Chemistry, vol. 8, no. 8, pp. 1326-1335.
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The formation of zinc hydroxide nitrate, Zn5(OH)8(NO3)22H2O, by reaction between zinc oxide and aqueous zinc nitrate solution was examined. Scanning electron microscopy, X-ray diffraction and thermogravimetric analysis were used to analyze the conversion of nanoscale ZnO particles into much larger crystals of the hydroxide nitrate. The rate of the reaction displayed sigmoidal behavior with the maximum conversion rate at ca. 75 min. The reaction stoichiometry involves a 1:1 ZnO/Zn(NO3)2 molar ratio. The data indicate that an amorphous zinc-containing intermediate phase is formed during the transition, and that the zinc hydroxide nitrate crystals nucleate and grow from this phase. The crystals of zinc hydroxide nitrate are several &micro;m in size, but are formed from zinc oxide crystals of only a few hundred nanometers in size, indicating that mass transfer in the aqueous phase plays an important role. We propose that H+-catalyzed dissolution/precipitation is the key process in the mechanism of the reaction. The zinc hydroxide nitrate is stable to about 110 &deg;C, but decomposes above that temperature to a series of less hydrated phases, with associated loss of mass, until zinc oxide is formed at about 190 &deg;C. The solubility product, Ksp, of Zn5(OH)8(NO3)22H2O in water was measured by two independent techniques and found to be in the range of 7.48.5??1011
Moezzi, A., McDonagh, A.M., Dowd, A.R. & Cortie, M.B. 2013, 'Zinc Hydroxyacetate And Its Transformation To Nanocrystalline Zinc Oxide', Inorganic Chemistry, vol. 52, no. 1, pp. 95-102.
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The synthesis of nanocrystalline ZnO by thermal decomposition of zinc hydroxyacetate, Zn-5(OH)(8)(CH3CO2)(2)center dot nH(2)O, was investigated. The decomposition process was examined using X-ray diffraction, thermogravimetric analysis, mass spectrometry
Moezzi, A., Cortie, M.B., Shimmon, R. & McDonagh, A.M. 2013, 'On the Reactivity of Zinc Hydroxide Acetate Dihydrate in Ethanol', European Journal Of Inorganic Chemistry, vol. 2013, no. 29, pp. 5133-5137.
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Zinc hydroxide acetate dihydrate, Zn-5(OH)(8)(CH3CO2)(2)2H(2)O, reacts in ethanol at room temperature to yield a mixture of zinc oxide and anhydrous zinc acetate. The process is driven by dehydration of the starting salt. Dehydration of Zn-5(OH)(8)(CH3CO
Moezzi, A., Cortie, M.B. & McDonagh, A.M. 2013, 'Zinc hydroxide sulphate and its transformation to crystalline zinc oxide', Dalton Transactions, vol. 42, no. 40, pp. 14432-14437.
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The thermal transformation of zinc hydroxide sulphate hydrate to zinc oxide has been examined using synchrotron X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and surface area measurements. By collecting X-ray diffraction da
Huyang, G., Canning, J., Petermann, I., Bishop, D.P., McDonagh, A.M. & Crossley, M.J. 2013, 'Room Temperature Sol-Gel Fabrication and Functionalization for Sensor Applications', Photonic Sensors, vol. 3, no. 2, pp. 168-177.
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The structure and physical properties of a thin titania sol-gel layer prepared on silicon and silica surfaces were examined. Spectroscopic (FTIR, UV-VIS spectroscopy), refractive index (ellipsometry) and microscopic (light microscopy and SEM/EDS) tools were used to examine both chemical uniformity and physical uniformity of the sol-gel glass layers. The conditions for the fabrication of uniform layers were established, and room temperature dopant incorporation was examined. The absorption bands of porphyrin-containing titania sol-gel layers were characterized. By addition of a metal salt to the titania layer, it was possible to metallate the free-base porphyrin within and change the UV-VIS absorbance of the porphyrin, the basis of metal detection using porphyrins. The metalloporphyrins were detected by localized laser ablation inductive coupled mass spectroscopy (LA-ICP-MS), indicating fairly uniform distribution of metals across the titania surface.
Chadwick, S.R., Maynard, P.J., Kirkbride, K.P., Lennard, C.J., McDonagh, A.M., Spindler, X. & Roux, C.P. 2012, 'Styryl dye coated metal oxide powders for the detection of latent fingermarks on non-porous surfaces', Forensic Science International, vol. 219, no. 1-3, pp. 208-214.
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Conventional fingermark powders rely on contrast induced by absorption/reflection (e.g. black powder) or luminescence in the visible region (e.g. Blitz Green&Acirc;&reg;). In most cases, these powders provide sufficient contrast; however, in some circumstances surface characteristics can interfere with the visualisation of powdered fingermarks. Visualisation in the near infra-red (NIR) region, however, has been shown to eliminate interferences commonly encountered in the visible region. In this study, a mixture of rhodamine 6G and the NIR laser dye styryl 11 (STaR 11) was coated onto an aluminium oxide nanopowder and then mixed with silver magnetic powder to develop and visualise fingermarks in the NIR. When compared to Blitz Green&Acirc;&reg;, it was determined that the STaR 11 magnetic powder was better suited for marks deposited on textured surfaces and for older marks, whereas Blitz Green&Acirc;&reg; performed better on smooth glossy surfaces. The ability of the STaR 11 mixed dye formulation to be visualised in both the visible and NIR regions also provides a significant advantage over conventional luminescent fingermark powders.
Rawling, T., McDonagh, A.M., Tattam, B. & Murray, M. 2012, 'Synthesis Of Unsymmetrical Biaryl Ureas From N-Carbamoylimidazoles: Kinetics And Application', Tetrahedron, vol. 68, no. 30, pp. 6065-6070.
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N-Carbamoylimidazoles dissociate in solution to yield imidazole and an isocyanate that may be reacted with another aryl amine to form an unsymmetrical biaryl urea. This paper investigates the reaction kinetics and the influence of electron withdrawing/do
Stokes, N.L., Cortie, M.B., Davis, T. & McDonagh, A.M. 2012, 'Plasmon Resonances In V-Shaped Gold Nanostructures', Plasmonics, vol. 7, no. 2, pp. 235-243.
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Using numerical simulations, we examine the change in plasmon resonance behavior in gold nanorod structures that have a V shape. The reduction in symmetry compared to linear rods causes two different longitudinal-type resonances to appear in a single str
Edgar, J.A., McDonagh, A.M. & Cortie, M.B. 2012, 'Formation Of Gold Nanorods By A Stochastic 'Popcorn' Mechanism', ACS Nano, vol. 6, no. 2, pp. 1116-1125.
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Gold nanorods have significant technological potential and are of broad interest to the nanotechnology community. The discovery of the seeded, wet-chemical synthetic process to produce them may be regarded as a landmark in the control of metal nanopartic
Moezzi, A., McDonagh, A.M. & Cortie, M.B. 2012, 'Zinc Oxide Particles: Synthesis, Properties And Applications', Chemical Engineering Journal, vol. 185, pp. 1-22.
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Zinc oxide powder has traditionally been used as a white pigment and as an additive to rubber. While it has largely been displaced as a pigment in paints, its usage in rubber remains very important. However, the myriad of other practical uses of ZnO are
El Saliby, I., Shahid, M., McDonagh, A.M., Shon, H. & Kim, J. 2012, 'Photodesorption of organic matter from titanium dioxide particles in aqueous media', Journal of Industrial and Engineering Chemistry, vol. 18, pp. 1774-1780.
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Photo-induced desorption of organic compounds from TiO2 particles in aqueous media during photocatalysis has promising applications in water treatment. Photodesorption is a relatively fast phenomenon that facilitates the regeneration of photocatalysts with low energy consumption while concentrating the waste products in an energy and water efficient process. We propose that this transport phenomenon involves a significantly reduced affinity between the photocatalyst and pollutants upon UV illumination, and leads to the rapid detachment/decomposition of adsorbed pollutants. In this study, we report the effect of experimental conditions (pH, photocatalyst loading, organic loading, UV light irradiation and flow rate) on this phenomenon in a recirculating photocatalysis continuous reactor. Initially, organic compounds were allowed to adsorb on the surface of the photocatalyst (Degussa P25) until adsorption equilibrium was achieved. The photodesorption phenomenon was observed shortly after UVlight illumination of TiO2 but before the bulk photocatalytic oxidation takes place. The pH of the solution was found to affect both the adsorption and the desorption percentages revealing the role of particle charge on this phenomenon. Additionally, a 1 g/L loading of photocatalyst showed an optimum photodesorption rate using a single strength synthetic wastewater at pH 7.
Gallagher, R., Shimmon, R. & McDonagh, A.M. 2012, 'Synthesis And Impurity Profiling Of MDMA Prepared From Commonly Available Starting Materials', Forensic Science International, vol. 223, no. 1-3, pp. 306-313.
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This work examines the synthesis of 3,4-methylenedioxy-N-methylamphetamine (MDMA) from common starting materials that may be utilised by clandestine laboratory operators. Piperonal was prepared from two common starting materials, piperine (from pepper) a
Ma, R., Shimmon, R., McDonagh, A., Maynard, P., Lennard, C. & Roux, C. 2012, 'Fingermark detection on non-porous and semi-porous surfaces using YVO4:Er,Yb luminescent upconverting particles', FORENSIC SCIENCE INTERNATIONAL, vol. 217, no. 1-3, pp. E23-E26.
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Ma, R., Bullock, E.A., Maynard, P.J., Reedy, B.J., Shimmon, R., Lennard, C.J., Roux, C.P. & McDonagh, A.M. 2011, 'Fingermark Detection On Non-Porous And Semi-Porous Surfaces Using Nayf(4):Er,Yb Up-Converter Particles', Forensic Science International, vol. 207, no. 1-Mar, pp. 145-149.
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This article describes the first use of an anti-Stokes material, or up-converter, for the development of latent fingermarks on a range of non-porous surfaces. Anti-Stokes materials can absorb long-wavelength light and emit light at a shorter wavelength. This property is unusual in both natural and artificial materials and so fingermark detection techniques based on anti-Stokes luminescence are potentially sensitive and selective. Latent fingermarks on luminescent and non-luminescent substrates, including Australian polymer banknotes (a well-known `difficult surface), were developed with sodium yttrium tetrafluoride doped with erbium and ytterbium (NaYF4:Er,Yb) by dry powder, wet powder, and cyanoacrylate staining techniques. This study illustrates the potential of up-converter phosphors for the detection of latent fingermarks.
Bossers, L., Roux, C.P., Bell, M. & McDonagh, A.M. 2011, 'Methods for the enhancement of fingermarks in blood', Forensic Science International, vol. 210, no. 1-3, pp. 1-11.
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Fingermarks formed in or by blood often require specific development techniques. This review examines techniques and materials that may be used to enhance and record fingermarks deposited in blood or fingermarks generated by blood-contaminated papillary ridges. A large number of techniques are presented here and are discussed from a chemical as well as practical perspective. It is concluded that an optimized sequence of techniques targeting both latent (non-bloody) and bloody fingermarks must be applied to detect and enhance the maximum number of marks, and therefore optimize the information content from exhibits that may bear marks in blood.
Spindler, X., Hofstetter, O., McDonagh, A.M., Roux, C.P. & Lennard, C.J. 2011, 'Enhancement of latent fingermarks on non-porous surfaces using anti-l-amino acid antibodies conjugated to gold nanoparticles', Chemical Communications, vol. 47, no. 19, pp. 5602-5604.
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Enantioselective anti-L-amino acid antibodies conjugated to gold nanoparticles are shown to facilitate the detection of latent fingermarks by interacting with amino acids present in friction ridge secretions. This antibody-based system is particularly effective for the enhancement of aged and dried fingermarks on non-porous surfaces, an area unexploited by current techniques.
Cortie, M.B. & McDonagh, A.M. 2011, 'Synthesis and optical properties of hybrid and alloy plasmonic nanoparticles', Chemical Reviews, vol. 111, no. 6, pp. 3713-3735.
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The plasmon resonances and other optical properties of elemental noble and alkali metal nanoparticles have generated enormous scienti?c interest. 1-11 There are numerous applications for plasmon-active nanoparticles, especially in areas such as biological microscopy, medicine, and sensors. 12-18 The various applications exploit some aspect of the plasmon resonance, which include particle-particle plasmon interactions, 19 the unusual coloring or dichroic e?ects in isolated particles, 20,21 light-induced plasmonic heating, 22 light scattering, 23 or twophoton phenomena. 24 Hybrid or multifunctional nanoparticles constructed from more than one component phase have also been attracting increasing interest due to their additional functionalities. 25-30 In this review, we consider speci?cally the optical properties of solid nanoparticles composed of more than one phase or compound. Alloyed nanoparticles (solid solutions or intermetallic compounds of the metallic elements) are also included because these intergrade with the two-phase hybrids
Cortie, M.B., Xiao, L.H., Erdei, L., Kealley, C.S., Dowd, A.R., Kimpton, J.A. & McDonagh, A.M. 2011, 'Thermal Stability of (KxNayH1-x-y)2Ti6O13 Nanofibers', European Journal Of Inorganic Chemistry, vol. 2011, no. 33, pp. 5087-5095.
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Potassium-rich titanate nanofibers were produced by digesting TiO2 in concentrated KOH solutions under hydrothermal conditions. The nanofibers were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and thermogravimetric analysis. A hexatitanate structure was assigned, in contrast to the trititanate structure usually resulting from NaOH treatment of TiO2. The potassium cations could be exchanged with others, such as sodium, hydrogen, and ammonium. The potassium-rich hexatitanate was found to be photocatalytic in its as-synthesized condition. The thermal stability of the fibers during calcination was followed in situ using X-ray diffraction and was found to be strongly dependent on the chemical composition. The potassium-rich titanate converted to anatase at only 480 &deg;C, whereas the hydrogen- and ammonium-rich materials had to be heated to over 600 &deg;C before conversion took place. Conversion was notably slowest in the ammonium-rich material. Surprisingly, the sodium-rich hexatitanate did not form anatase at temperatures up to 800 &deg;C and instead recrystallized.
Samoc, M., Corkery, T.C., McDonagh, A.M., Cifuentes, M.P. & Humphrey, M.G. 2011, 'Organometallic complexes for non-linear optics 49: Third-order non-linear optical spectral dependence studies of Arylalkynylruthenium Dendrimers', Australian Journal Of Chemistry, vol. 64, pp. 1269-1273.
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The cubic hyperpolarizabilities of the zero-generation dendrimers 13 and related first generation dendrimers have been assessed over the spectral range 5201600 nm using the Z-scan technique and ~150 fs pulses. The complexes exhibit self-defocusing behaviour and two-photon absorption at short wavelengths, and three-photon absorption at longer wavelengths.
Moezzi, A., Cortie, M.B. & McDonagh, A.M. 2011, 'Aqueous pathways for the formation of zinc oxide nanoparticles', Dalton Transactions, vol. 40, no. 18, pp. 4871-4878.
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We examine the effect of reactant concentrations, temperatures and feeding methods on the morphology of ZnO formed when reacting solutions of ZnSO4 and NaOH. The catalytic effect of hydroxide in excess relative to the stoichiometric ratio is considered. It is shown that, having fixed other reaction conditions, the end-products, particle structures and size strongly depend on the mole ratio of the precursors. The presence of zinc salt hydroxide species was confirmed at sub-stoichiometric ratios in slightly acidic conditions. At the stoichiometric ratio both zinc hydroxide and zinc oxide are formed, while only zinc oxide forms in an excess of hydroxide. The method of feeding the reactants into the reaction vessel also has a strong influence on the end-product properties, as does the reaction temperature. By control of these parameters the specific surface area could be varied from 10 to 33 m2 g-1, the particle shape could be varied from equiaxed, through to star-like and needle-like, and the particle size may be varied from 50 to over 300 nm.
Austin, C.E., Fryer, F.I., Lear, J., Bishop, D.P., Hare, D.J., Rawling, T., Kirkup, L., McDonagh, A.M. & Doble, P.A. 2011, 'Factors Affecting Internal Standard Selection For Quantitative Elemental Bio-Imaging Of Soft Tissues By LA-ICP-MS', Journal of Analytical Atomic Spectrometry, vol. 26, no. 7, pp. 1494-1501.
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Element response variations under different laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) operating conditions were investigated to identify important factors for selecting an internal standard (IS) for quantitative elemental bi
Austin, C.E., Hare, D.J., Rawling, T., McDonagh, A.M. & Doble, P.A. 2010, 'Quantification method for elemental bio-imaging by LA-ICP-MS using metal spiked PMMA films', Journal of Analytical Atomic Spectrometry, vol. 25, no. 5, pp. 722-725.
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A method for quantitative analysis of biological soft tissues by laser ablation-inductively coupled plasma-mass spectrometry has been developed. Polymer film standards were produced by spin coating spiked solutions of poly methyl methacrylate onto quartz substrates. Calibration curves throughout the range of 0--400"llg g-l yielded correlation coefficients better than 0.999 for 66Zn and 63CU. Spiked, homogenised soft tissue standards were quantified by LA-ICP-MS against the thin film standards. The results agreed with values calculated from solution nebulisation rCP-MS. A procedure for internal standardisation by employing ruthenium or yttrium in the underlying thin film was also assessed.
Coutts, M.J., Zareie, H.M., Cortie, M.B., Phillips, M., Wuhrer, R. & McDonagh, A.M. 2010, 'Exploiting Zinc Oxide Re-Emission To Fabricate Periodic Arrays', ACS Applied Materials & Interfaces, vol. 2, no. 6, pp. 1774-1779.
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The synthesis of hexagonal ring-shaped structures of zinc oxide using nanosphere lithography and metal/metal oxide sputtering is demonstrated. This synthesis exploits the surface re-emission of zinc oxide to deposit material in regions lying out of the l
Rawling, T., Austin, C.E., Zareie, H.M. & McDonagh, A.M. 2010, 'Thin Films Of A Dimeric Ruthenium Phthalocyanine Complex On Gold', Inorganic Chemistry Communications, vol. 13, no. 1, pp. 208-210.
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Thin films of a new dimeric ruthenium phthalocyanine complex bearing a thioester-functionalized axial ligand were formed on gold surfaces. Characterization of the thin films by laser ablation-inductively coupled-mass spectrometry and scanning tunneling m
Stokes, N.L., Edgar, J.A., McDonagh, A.M. & Cortie, M.B. 2010, 'Spectrally selective coatings of gold nanorods on architectural glass', Journal of nanoparticle Research, vol. 12, no. 8, pp. 2821-2830.
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Infrared-blocking coatins n window glass can be produced by dispersing gold nanorods into a polymer coating. The spectral selectivity of the coating is controlled by the shape and aspect ration of the nanoparticles, which are in turn determined by the conditions applied during their synthesis. Coatings of nanorods in polyvinyl alcohol were deposited onto glass and characterised in both laboratory and sun-lit conditions. Selective attenuation of the near-infrared was demonstrated with the test panels transmitting approximately one-third of the incident solar radiatyion and absorbing nearly two-thirds. The high absoprtive cross sections of the gold nanorods suggest that they can be applied in efficacious coatings at relatively low volume fractions.
Cortie, M.B., Stokes, N.L. & McDonagh, A.M. 2009, 'Plasmon resonance and electric field amplification of crossed gold nanorods', Photonics and Nanostructures: Fundamentals and Applications, vol. 7, no. 3, pp. 143-152.
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Here we explore the unusual plasmon resonances of crossed gold nanorod structures of varying geometries. Using numerical simulations, we show that the resonances of simple rods are hybridized and blue-shifted in the composite structures and that these structures are surrounded by spatially extended and high intensity electric fields. This attribute suggests several potential uses for these shapes, for example as a nano-antenna for the generation of two-photon fluorescence.
Rawling, T., Austin, C.E., Buchholz, F., Colbran, S.B. & McDonagh, A.M. 2009, 'Ruthenium Phthalocyanine-Bipyridyl Dyads as Sensitisers for Dye-Sensitised Solar Cells: Dye Coverage versus Molecular Efficiency', Inorganic Chemistry, vol. 48, no. 7, pp. 3215-3227.
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The application of ruthenium phthalocyanine complexes as sensitizing dyes in dye-sensitized solar cells (DSCs) is explored. Four monomeric complexes are reported which vary in peripheral substitution and axial ligand anchoring groups. Sensitizing dyes containing two ruthenium centers are also presented. These dyads, which contain ruthenium phthalocyanine and bipyridyl chromophores, were prepared using a protection/deprotection strategy that allows for convenient purification. DSCs fabricated using the phthalocyanine complexes and dyads were less efficient than those incorporating a standard DSC dye. However, on the basis of the number of molecules bound to the TiO2 electrode surfaces, several of the new complexes were more efficient at pholocurrent generation. The results highlight the importance of molecular size, and thus the dye coverage of the electrode surface in the design of new sensitizing dyes.
Maynard, P.J., Jenkins, J., Edey, C., Payne, G.L., Lennard, C.J., McDonagh, A.M. & Roux, C.P. 2009, 'Near infrared imaging for the improved detection of fingermarks on difficult surfaces', Australian Journal of Forensic Sciences, vol. 41, no. 1, pp. 43-62.
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The near infrared spectral region offers advantages over the visible region in the detection of latent fingermarks due to increased contrast and decreased background luminescence. In this work, a chemical imaging system was used to image latent fingermarks in the near-infrared (NIR) region. A variety of porous, non-porous and semi-porous surfaces were tested using standard chemical and physical enhancement techniques. NIR dyes were also used to enhance latent marks. Both absorption and luminescence properties of the treated marks were examined over the spectral range 650-1100 nm. Significant NIR absorption was found for ninhydrin, iodine/benzoflavone, physical developer, and powdering. NIR luminescence emission was found for DFO, ninhydrin with zinc salt post treatment, 1,2-indanedione and genipin. Significant NIR luminescence emission was found for cyanoacrylate fuming followed by staining with NIR dyes. In addition, metal oxide powders coated with NIR dyes were able to enhance fingermarks on a patterned and highly luminescent surface.
Rawling, T., Austin, C.E., Hare, D.J., Doble, P.A., Zareie, H.M. & McDonagh, A.M. 2009, 'Thin films of Ruthenium Phthalocyanine complexes', Nano Research, vol. 2, pp. 678-687.
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Four new ruthenium phthalocyanine complexes bearing axial ligands with thioacetate groups that facilitate thin film formation on gold surfaces are presented. Scanning tunnelling microscopy (STM) images and surface coverage data obtained by solution inductively coupled plasma mass spectrometry (ICP-MS) experiments show that peripheral and axial ligand substituents on the complexes have a significant effect on their surface coverage. A laser ablation ICP-MS technique that provides information about thin films across macro-sized areas is described here for the first time. Using the technique, the maximum surface coverage of a ruthenium phthalocyanine complex was found to occur within one minute of gold substrate immersion in the complexcontaining solution.
Coutts, M.J., Cortie, M.B., Ford, M. & McDonagh, A.M. 2009, 'Rapid and Controllable Sintering of Gold Nanoparticle Inks at Room Temperature Using a Chemical Agent', Journal of Physical Chemistry C, vol. 113, no. 4, pp. 1325-1328.
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We show that oxidation of protective thiol ligands and the exothermic reduction of surface area are important factors in the sintering of thiol-stabilized gold nanoparticle films. We also present a chemical treatment to achieve sintering of gold nanoparticles at room temperature. The process is facilitated by the remarkable enthalpy of reaction arising from the reduction of the surface area of the nanoparticles.
Rawling, T., Austin, C.E., Hare, D.J., Doble, P.A., Zareie, H.M. & McDonagh, A.M. 2009, 'Thin films of Ruthenium Phthalocyanine complexes', Nano Research, vol. 2, pp. 678-687.
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Four new ruthenium phthalocyanine complexes bearing axial ligands with thioacetate groups that facilitate thin film formation on gold surfaces are presented. Scanning tunnelling microscopy (STM) images and surface coverage data obtained by solution inductively coupled plasma mass spectrometry (ICP-MS) experiments show that peripheral and axial ligand substituents on the complexes have a significant effect on their surface coverage. A laser ablation ICP-MS technique that provides information about thin films across macro-sized areas is described here for the first time. Using the technique, the maximum surface coverage of a ruthenium phthalocyanine complex was found to occur within one minute of gold substrate immersion in the complexcontaining solution.
Rawling, T., McDonagh, A.M. & Colbran, S.B. 2008, 'Synthesis, Electrochemistry and Spectroscopic Properties of Ruthenium Phthalocyanine and Naphthalocyanine Complexes with Triphenylarsine Ligands', Inorganic Chimica Acta, vol. 361, pp. 49-55.
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The synthesis, electrochemistry and spectroscopic properties of [PcRu(AsPh3)2] (1) and [{(tBu)4Nc}Ru(AsPh3)2] (2), where Pc = phthalocyanine and Nc = naphthalocyanine are reported. These complexes are the first examples of metal phthalocyanine and naphthalocyanine complexes with axially-coordinated arsine ligands. The AsPh3 ligands readily dissociate in non-coordinating solvents with 2 showing more rapid dissociation. In cyclic voltammetry experiments, 1 displayed three macrocycle-centred redox processes; one reduction and two oxidation processes. One reduction and three oxidation processes were observed for 2. The reduction and first oxidation are assigned to macrocycle-centred processes. The UVVis spectra of both complexes recorded over time showed macrocycle-centred oxidation. The oxidation was hindered by removing dioxygen from the solvent or adding excess AsPh3.
Rawling, T., Buchholz, F. & McDonagh, A.M. 2008, 'Convenient synthesis and purification of [Bu4N](2)[Ru(4-carboxy-4-carboxylate-2,2 '-bipyridine)(2)(NCS)(2)]: a landmark DSC dye', Australian Journal Of Chemistry, vol. 61, no. 6, pp. 405-408.
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We present here a convenient synthesis of the landmark dye-sensitized solar cell dye [Bu4N](2)[Ru(4-carboxy-4-carboxylate-2,2'-bipyridine)(2)(NCS)(2)] (N719). Key to this synthetic procedure is the protection of the carboxyl functionalities with iso-buty
Choi, M., McDonagh, A.M., Maynard, P.J. & Roux, C.P. 2008, 'Metal-containing Nanoparticles and Nano-structured Particles in Fingermark Detection', Forensic Science International, vol. 179, no. 2-3, pp. 87-97.
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This article reviews the application of metal-containing nanoparticles and nano-structured particles to fingermark detection. This area of research is attracting significant interest as advances in nanoscience are being incorporated into the field of forensic fingermark detection. Although more research is needed before some of the techniques presented can be implemented in routine casework, nanotechnology is likely to play a major role in the future to deliver more selective and more sensitive ways to detect and enhance fingermarks.
Ford, M., Hoft, R.C., McDonagh, A.M. & Cortie, M.B. 2008, 'Rectification in Donor-Acceptor Molecular Junctions', Journal Of Physics: Condensed Matter, vol. 20, no. 37, pp. 1-8.
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We perform density functional theory (DFT) calculations on molecular junctions consisting of a single molecule between two Au(111) electrodes. The molecules consist of an alkane or aryl bridge connecting acceptor, donor or thiol endgroups in various combinations. The molecular geometries are optimized and wavefunctions and eigenstates of the junction calculated using the DFT method, and then the electron transport properties for the junction are calculated within the non-equilibrium Green's function (NEGF) formalism. The currentvoltage or i(V) characteristics for the various molecules are then compared. Rectification is observed for these molecules, particularly for the donorbridgeacceptor case where the bridge is an alkane, with rectification being in the same direction as the original findings of Aviram and Ratner (1974 Chem. Phys. Lett. 29 27783), at least for relatively large negative and positive applied bias. However, at smaller bias rectification is in the opposite direction and is attributed to the lowest unoccupied orbital associated with the acceptor group.
Stokes, N.L., McDonagh, A.M. & Cortie, M.B. 2008, 'Preparation of Nanoscale Gold Structures by Nanolithography', Gold Bulletin, vol. 40, no. 4, pp. 310-320.
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Gold is the material of first choice for the realisation of a large number of interesting nanoscale devices and structures due to its unique chemical and optical properties. However, conventional photolithographic processes cannot be used to manufacture such tiny structures in gold (or any other material) due to limitations imposed by the diffraction of light. New methods of lithography have been developed to overcome this limitation. In this article we review these new nanolithographic techniques, describe how they have been used to produce nanoscale precious metal artefacts, and briefly survey some of the existing and potential applications for these structures.
West, P.J., Zareie, H.M. & McDonagh, A.M. 2008, 'Synthesis and characterization of anthracene-2,6-dithioacetate: a rigid, conjugated molecule for the formation of monolayers on gold', Australian Journal Of Chemistry, vol. 61, no. 10, pp. 758-761.
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The synthesis and characterization of a new photoswitchable anthracene compound, anthracene-2,6-dithioacetate, is presented. The compound dimerizes in solution on irradiation with UV light, and thin films can be formed on gold surfaces from both the monomer and photodimer.
Choi, M., McBean, K.E., McDonagh, A.M., Maynard, P.J., Lennard, C.J. & Roux, C.P. 2008, 'An evaluation of nanostructured zinc oxide as a fluorescent powder for fingerprint detection', Journal of Materials Science, vol. 43, no. 2, pp. 732-737.
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Zinc oxide is evaluated as a fluorescent powder for the detection of fingermarks on non-porous surfaces. Pure and lithium-doped nanostructured zinc oxide powders were characterized using scanning electron microscopy, X-ray diffraction, and fluorescence spectroscopy. The zinc oxide powders were applied to fresh and aged fingermarks deposited on non-porous surfaces such as glass, polyethylene and aluminium foil. Zinc oxide was found to produce clear fluorescent impressions of the latent fingermarks when illuminated with long-wave UV light
Ford, M.J., Hoft, R.C., McDonagh, A.M. & Cortie, M.B. 2008, 'Rectification in donor-acceptor molecular junctions', JOURNAL OF PHYSICS-CONDENSED MATTER, vol. 20, no. 37.
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McDonagh, A.M., Zareie, H.M., Ford, M., Barton, C., Ginic-markovic, M. & Matisons, J. 2007, 'Ethynylbenzene monolayers on gold A metal-molecule binding motif derived from a hydrocarbon', Journal Of The American Chemical Society, vol. 129, no. 12, pp. 3533-3538.
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Exposure of a Au(111) surface to ethynylbenzene in solution leads to the formation of a bound monolayer. A chemisorption process occurs to give a stable layer consisting of oxygen-containing hydrocarbon species. Ethynylbenzene itself does not oxidize under the deposition conditions indicating that the gold surface facilitates the oxidation process. Calculations show that ethynylbenzene and its oxidation products phenylacetic acid and phenylxirane have positive bending energies to the gold surface. 1,4- Diethynylbenzene also bind to Au (111) and anchors gold nanoparticles deposited from solution to form dense, semiregular arrays.
Rawling, T., Xiao, H., Lee, S., Colbran, S.B. & McDonagh, A.M. 2007, 'Optical and redox properties of ruthenium phthalocyanine complexes tuned with axial ligand substituents', Inorganic Chemistry, vol. 46, no. 7, pp. 2805-2813.
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The optical and electrochemical properties of the ruthenium phthalocyanine complexes [{(t-Bu)(4)Pc}Ru(4-Rpy)(2)], where R = NO2, Me, NH2, and NMe2, are reported. The electron density at the macrocycle may be adjusted using the axial ligand substituents,
Armstrong, N.G., Hoft, R.C., McDonagh, A.M., Cortie, M.B. & Ford, M. 2007, 'Exploring The Performance Of Molecular Rectifiers Limitations And Factors Affecting Molecular Rectification', Nano Letters, vol. 7, no. 10, pp. 3018-3022.
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There has been significant work investigating the use of molecules as nanoscale rectifiers in so-called molecular electronics. However, less attention has been paid to optimizing the design parameters of molecular rectifiers or to their inherent limitati
Lucas, N.T., Zareie, H.M. & McDonagh, A.M. 2007, 'Self-organization of a Discotic Coordination Complex Bearing Orthogonal Discotic Ligands', ACS Nano, vol. 1, no. 4, pp. 348-354.
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Rawling, T. & McDonagh, A.M. 2007, 'Ruthenium Phthalocyanine And Naphthalocyanine Complexes: Synthesis, Properties And Applications', Coordination Chemistry Reviews, vol. 251, no. 9-10, pp. 1128-1157.
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This article reviews the synthesis of ruthenium phthalocyanine and naphthalocyanine complexes highlighting important advances, and examines their physical properties and applications. (c) 2006 Elsevier B.V. All rights reserved.
Choi, M., Smoother, T., Martin, A.A., McDonagh, A.M., Maynard, P.J., Lennard, C.J. & Roux, C.P. 2007, 'Fluorescent TiO2 powders prepared using a new perylene diimide dye: Applications in latent fingermark detection', Forensic Science International, vol. 173, no. 2, pp. 154-160.
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A new, highly fluorescent dye was synthesised using oleylamine combined with a perylene dianhydride compound. The new dye was characterised by H-1 NMR, UV-vis spectroscopy and fluorescence spectroscopy as well as quantum yield. The dye was absorbed onto
Maharaj, F., McDonagh, A.M. & Colbran, S.B. 2007, 'The Instructive Redox Behaviour Of 4-ferrocenylcatechol On Nanocrystalline Titanium Dioxide Electrodes', Applied Organometallic Chemistry, vol. 21, no. 2, pp. 73-75.
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An investigation into the redox behaviour of 4-ferrocenylcatechol bound to nanocrystalline TiO2 electrodes identified a limitation to the use of catechol as an electron-transfer facilitating anchoring group. 4-Ferrocenylcatechol was adsorbed to transparent nanocrystalline TiO2 electrodes. UV-visible spectra of the modified electrode were recorded in an acetonitrile-electrolyte solution. At an applied potential of + 0.45 mV (vs Ag/AgCl/Cl-) the ferrocenyl group oxidized to the ferrocenium cation and the catecholate group oxidized to the benzoquinone form. Subsequent application of a potential of 0 V reduced the ferrocenium to ferrocene but, owing to the irreversibility of the catechol oxidation in aprotic solvents, benzoquinone is not reduced to catecholate and subsequently desorbs and is lost due into solution. Electrochromic switching of the ferrocenyl electrochromophore on TiO2 with aprotic electrolyte is, therefore, irreversible. Copyright &copy; 2006 John Wiley & Sons, Ltd.
Harris, N., Ford, M., Cortie, M.B. & McDonagh, A.M. 2007, 'Laser-induced Assembly Of Gold Nanoparticles Into Colloidal Crystals', Nanotechnology, vol. 18, no. 36, pp. 1-4.
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Micron-sized colloidal crystals comprised of gold nanospheres have been synthesized directly from a gold nanoparticlepermethyl methacrylate colloid by application of a 514 nm laser at 500 mW. An array of colloidal crystals can be created by translation o
Hoft, R.C., Ford, M., McDonagh, A.M. & Cortie, M.B. 2007, 'Adsorption Of Amine Compounds On The Au(111) Surface: A Density Functional Study', Journal Of Physical Chemistry C, vol. 111, no. 37, pp. 13886-13891.
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A Density Functional Theory study of the adsorption energetics of various amine compounds on the gold(111) surface revealed that preferential binding occurs in under-coordinated sites. The largest binding energy is obtained when a gold adatom is placed i
Zareie, H.M., Barber, J. & McDonagh, A.M. 2006, 'Structural changes in self-assembled monolayers initiated by ultraviolet light', Journal Of Physical Chemistry B, vol. 110, no. 32, pp. 15951-15954.
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Self-assembled monolayers of 2-anthracenethiol and 2-naphthalenethiol on gold (111) were irradiated with low-power UV light. Scanning tunneling microscope images recorded in situ show unusual structural changes. In the case of 2-anthracenethiol, structur
Zareie, H.M., McDonagh, A.M., Edgar, J.A., Ford, M., Cortie, M.B. & Phillips, M. 2006, 'Controlled assembly of 1,4-phenylenedimethanethiol molecular nanostructures', Chemistry Of Materials, vol. 18, no. 9, pp. 2376-2380.
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We present here the first high-resolution scanning tunneling microscope images showing that 1,4phenylenedimethanethiol forms mono- and multilayers on gold(1 11) substrates under particular solution-deposition conditions. The high-resolution images show t
Choi, M., McDonagh, A.M., Maynard, P.J., Wuhrer, R., Lennard, C.J. & Roux, C.P. 2006, 'Preparation and evaluation of metal nanopowders for the detection of fingermarks on nonporous surfaces', Journal of Forensic identification, vol. 56, no. 5, pp. 756-768.
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gold and silver nanoparticles using oleylamine as a stabilizer have been formulated for developing latent fingermarks on nonporous surfaces. These nanopowders are compared with conventional powders such as black powder, black magnetic powder, aluminium powder and white powder. Gold nanopowder produced sharp and clear development of latent fingermarks without background staining. Scanning electron microscope images revealed that particles were concentrated inthe fingermark ridge areas, with only minor amounts located in the valley regions.
Colbran, S.B., Lee, S., Lonnon, D., Maharaj, F., McDonagh, A.M., Walker, K. & Young, R.C. 2006, 'Covalently Linked Ferrocenyl Quinones Proton-dependent Redox Behavior And Charge Redistribution', Organometallics, vol. 25, no. 9, pp. 2216-2224.
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The proton-dependent redox chemistry of dyads comprised of a ferrocenyl electron donor directly linked to a hydroquinonyl electron donor or to a quinone electron acceptor by a single covalent bond has been characterized. Ferrocenyl-1,4-hydroquinone (2), ferrocenyl-1,4-benzoquinone (3), 3-ferrocenyl-1,2-catechol (5), and the precursors ferrocenyl-1,4-dimethoxybenzene (1) and 3-ferrocenyl-1,2-dimethoxybenzene (4) were studied; also the unstable compound 3-ferrocenyl-1,2-benzoquinone (6) was observed in the spectroelectrochemistry of 5. Detailed cyclic voltammetry, coulommetry, and UV-vis-NIR spectroelectrochemistry experiments allied with EPR, NMR, and M&ouml;ssbauer spectroscopy were used to probe the pH-dependent redox chemistry and electron distribution within the compounds.
Cifuentes, M.P., Powell, C.E., Morrall, J.P., McDonagh, A.M., Lucas, N.T., Humphrey, M.G., Samoc, M., Houbrechts, S., Asselberghs, I., Clays, K., Persoons, A. & Isoshima, T. 2006, 'Electrochemical, Spectroelectrochemical, Molecular Quadratic and Cubic Nonlinear Optical Properties of Alkynylruthenium Dendrimers', Journal of the American Chemical Society, vol. 128, no. 33, pp. 10819-10832.
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A combination of cyclic voltammetry (CV), UV-vis-NIR spectroscopy and spectroelectrochemistry, hyper-Rayleigh scattering (HRS) [including depolarization studies], Z-scan and degenerate four-wave mixing (DFWM) [including studies employing an optically transparent thin-layer electrochemical (OTTLE) cell to effect electrochemical switching of nonlinearity], pump-probe, and electroabsorption (EA) measurements have been used to comprehensively investigate the electronic, linear optical, and nonlinear optical (NLO) properties of nanoscopic pi-delocalizable electron-rich alkynylruthenium dendrimers, their precursor dendrons, and their linear analogues. CV, UV-vis-NIR spectroscopy, and UV-vis-NIR spectroelectrochemistry reveal that the reversible metal-centered oxidation processes in these complexes are accompanied by strong linear optical changes, switching on low-energy absorption bands, the frequency of which is tunable by ligand replacement. HRS studies at 1064 nm employing nanosecond pulses reveal large nonlinearities for these formally octupolar dendrimers; depolarization measurements are consistent with lack of coplanarity upon pi-framework extension through the metal.
Lucas, N.T., McDonagh, A.M., Dance, I., Colbran, S.B. & Craig, D.C. 2006, 'cis-[PtBr2{PPh2(4-catechol))}(2)]: synthesis, crystal structure, and computational modelling of its binding to nanocrystalline TiO2', Dalton Transactions, vol. 5, no. 1, pp. 680-685.
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The complex cis-[PtBr2{PPh2(4-catechol)}2] 1 has been synthesized by cleavage of the four methyl groups from cis-[PtCl2{PPh2(4-veratrole)}2] using BBr3, followed by work-up in the presence of excess bromide. An X-ray crystal structure of 1(ethanol)2 confirms that the two catechol rings are adjacent to each other and approximately parallel, and therefore well structured to act as double bidentate ligands for adjacent metal atoms on the surface of a nanocrystal. The crystal packing of 1(ethanol)2 involves intermolecular hydrogen-bonding interactions and a parallel fourfold phenyl embrace between PPh2 moieties. Density functional calculations have demonstrated that conformational variability of the aryl rings in cis-[PtBr2{PPh2(4-catechol)}2] is energetically feasible, and two conformations of cis-[PtBr2{PPh2(4-catechol)}2] as a complex ligand for Ti atoms on the various surfaces of the anatase and rutile structures of TiO2 have been assessed for geometrical commensurability. Three structural models for adsorbates of cis-[PtBr2{PPh2(4-catechol)}2] on TiO2 are developed for anatase (110), anatase (101), and rutile (001).
Choi, M., McBean, K.E., Wuhrer, R., McDonagh, A.M., Maynard, P.J., Lennard, C.J. & Roux, C.P. 2006, 'Investigation into the binding of gold nanoparticles to fingermarks using scanning electron microscopy', Journal of Forensic identification, vol. 56, no. 1, pp. 24-32.
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For the first time, scanning electron microscopy has been used to investigate the binding of gold nanoparticles to fingermarks placed on nanoporous surfaces. The results show that gold nanoparticles, under standard MMDII conditions, bind preferentially to latent fingermark ridges on nonporous surfaces. Variation in surfactant concentration influences background development but does not affect the binding of gold nanoparticles to the ridges, while pH variation influences the binding to ridges but leaves valley regions unaffected.
Zareie, M.H., Barber, J. & McDonagh, A.M. 2006, 'Structural changes in self-assembled monolayers initiated by ultraviolet light.', The journal of physical chemistry. B, vol. 110, no. 32, pp. 15951-15954.
Self-assembled monolayers of 2-anthracenethiol and 2-naphthalenethiol on gold (111) were irradiated with low-power UV light. Scanning tunneling microscope images recorded in situ show unusual structural changes. In the case of 2-anthracenethiol, structures measuring 4-7 nm wide and 30-40 nm in length are formed. Images taken 10 min after irradiation ceased to show further surface reorganization. With 2-naphthalenethiol SAMs, smaller structures form upon irradiation, which subsequently revert to resemble the original structure after time.
Lucas, N.T., Hook, J.M., McDonagh, A.M. & Colbran, S.B. 2005, 'Titanium dioxide nanoparticles functionalized with Pd and W complexes of a catecholphosphane ligand', European Journal Of Inorganic Chemistry, vol. 3, pp. 496-503.
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Palladium and tungsten complexes containing the bifunctional ligand 4-diphenylphosphanylcatechol (L-1) have been synthesized. The catecholate functionality strongly binds to titanium dioxide nanoparticles, effectively anchoring the complexes to the TiO2
Ford, M., Hoft, R.C. & McDonagh, A.M. 2005, 'Theoretical study of ethynylbenzene adsorption on Au(111) and implications for a new class of self-assembled monolayer', Journal Of Physical Chemistry B, vol. 109, no. 43, pp. 20387-20392.
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Density functional calculations of the adsorption of ethynylbenzene on the Au(I 11) surface show that, after cleavage of the C-H bond, the terminal carbon makes a strong covalent bond to the surface. The bond energy is shown to be about 70 kcal(.)mol(-1)
McDonagh, A.M., Powell, C.E., Morrall, J.P., Cifuentes, M.P. & Humphrey, M.G. 2003, 'Convergent synthesis of alkynylbis(bidentate phosphine)ruthenium dendrimers', Organometallics, vol. 22, no. 7, pp. 1402-1413.
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The "first-generation" alkynylruthenium dendrimers 1,3,5-C6H3(4-CCC6H4CC-trans-[Ru(dppe)2]CC-3,5-C6H3{4-CCC6H4CC-trans-[Ru(4-CCC6H4R)(dppe)2]}2)3 [R = H (19), NO2 (20)], containing nine dialkynylruthenium centers, have been prepared by convergent synthesis. Reaction of 3 equiv of 1-iodo-4-trimethylsilylethynylbenzene with triethynylbenzene, under Sonogashira coupling conditions, followed by deprotection with tetra-n-butylammonium fluoride affords 1,3,5-C6H3(4-CCC6H4CCH)3 (2), which is reacted with cis-[RuCl2(L)2] (L = dppe, dppm) to afford the octopolar, triruthenium dendritic cores 1,3,5-C6H3{4-CCC6H4CC-trans-[RuCl(L)2]}3 [L = dppe (5), L = dppm (6)] via the vinylidene intermediates [1,3,5-C6H3{4-CCC6H4CH=C-trans-[RuCl(L)2]}3](PF6)3 [L = dppe (3), L = dppm (4)]. Reaction of 5 with terminal alkynes 4-HCCC6H4R (R = H, NO2, NEt2) affords a series of related dialkynylruthenium zero-generation dendrimers 1,3,5-C6H3{4-CCC6H4CC-trans-[Ru(4-CCC6H4R)(dppe)2]}3 [R = H (7), NO2 (8), NEt2 (9)]. Reaction of 3 equiv of trans-[Ru(4-CCC6H4CCH)(CCPh)(dppe)2] with 1,3,5-triiodobenzene under Sonogashira coupling conditions also affords 7, together with the homo-coupled trans,trans-[(dppe)2(PhCC)Ru(4,4'-CCC6H4CCCCC6H4CC)Ru(CCPh)(dppe)2]. The first-generation dendrimers 19 and 20 are prepared by coupling core 5 with the dendrons 1-(HCC)C6H3-3,5-{4-CCC6H4CC-trans-[Ru(4-CCC6H4R)(dppe)2]}2 [R = H (17), NO2 (18)].
McDonagh, A.M., Clays, K., Persoons, A., Asselberghs, I., Ward, M.D. & McCleverty, J.A. 2003, 'In situ reversible electrochemical switching of the molecular first hyperpolarizability', Chemical Physics Letters, vol. 368, no. 3-4, pp. 408-411.
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In situ reversible electrochemical switching of the molecular second-order nonlinear optical (NLO) polarizability, or first hyperpolarizability, has been implemented in a specially designed cell. The redox-switchable NLO chromophore is based on the octamethylferrocene/octamethylferrocenium redox system as electron-donor (D) group, in conjunction with nitrothiophene as the electron-acceptor (A) group and ethenyl as the ?-conjugation bridge. This D?A chromophore has been shown to exhibit reversible redox switching of its linear and nonlinear optical properties. The importance and potential of this electrochemical switching of the first hyperpolarizability is discussed in the context of current and future applications of second-order NLO effects.
Powell, C.E., Cifuentes, M.P., McDonagh, A.M., Hurst, S.K., Lucas, N.T., delfs, C., Stranger, R., Humphrey, M.G., Houbrechts, S., Asselberghs, I., Persoons, A. & Hockless, D. 2003, 'Organometallic complexes for nonlinear optics. Part 27. Syntheses and optical properties of Some Iron, Ruthenium and Osmium Alkynyl Complexes', Inorganica Chimica Acta, vol. 352, no. 6, pp. 9-18.
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The syntheses of the alkynyl complexes M(4-C6-point triple bond; length half of m-dashCC6H4NO2)(dppe)(?-C5H5) [M=Fe (1), Ru (2), Os (3)], Os(4-C6-point triple bond; length half of m-dashCC6H4NO2)(PPh3)2(?-C5H5) (4) and Ru(4-C6-point triple bond; length half of m-dashCC6H4NO2)(CO)2(?-C5H5) (5) are reported. Structural studies reveal a decrease in Ru---C(1) distance on proceeding from 5 to 2, consistent with greater back-donation of electron density to the alkynyl ligand from the more electron-rich metal center in 2. Electrochemical data show that the MII/III couple for the dicarbonyl complex 5 is at a significantly more positive potential than that of the related diphosphine complex 2, consistent with ligand variation modifying the electron richness and hence donor strength of the metal center. Time-dependent density functional calculations on model complexes M(4-C6-point triple bond; length half of m-dashCC6H4NO2)(PH3)2(?-C5H5) (M=Fe, Ru, Os) have been employed to assign the intense low-energy optical transition in these complexes as MLCT in character, the higher energy band being phenylphenyl* in nature. Molecular quadratic optical nonlinearities have been measured using the hyper-Rayleigh scattering procedure at 1064 nm. ? values vary as Fe?Ru?Os for metal variation and CO<phosphines for co-ligand variation, the latter consistent with the variation in donor strength of the metal center inferred from electrochemical and crystallographic data. The observed trend in ? on metal variation follows the trend in backbonding energies calculated by DFT.
Wheatley, M., McDonagh, A.M., Brungs, M., Chaplin, R. & Sizgek, R. 2003, 'A study of reverse bias in a dye sensitised photoelectrochemical device', SOLAR ENERGY MATERIALS and SOLAR CELLS, vol. 76, no. 2, pp. 175-181.
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A dye-sensitized nanocrystalline solar subjected to reverse bias of800 mV showed no measurable loss in performance. However, at 2000 mV, a dramatic and irreversible reduction in the cells performance is observed. Raman spectroscopy experiments suggested that no desorption ofthe photosensitising dye occurred. Spectroelectrochemical experiments revealed that an irreversible loss ofintensity in the metal to ligand charge transfer band at 540nm occurred. In practical terms, these results indicate that cells which are incorrectly connected to an array ofcells or a system failure where potentials greater than 1500mV are present, may be irreversibly damaged.
Maharaj, F., McDonagh, A.M., Scudder, M., Craig, D.C. & Dance, I. 2003, 'Crystal packing principles for ferrocenyl groups linked by polyyne chains: dimorphism of Fc-C4-Fc', CrystEngComm, vol. 5, no. 5, pp. 305-309.
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The crystal structure and packing of a new dimorph ( 2B) of 1,4-diferrocenyl-1,3-butadiyne (Fc-C4-Fc, 2) is described and analysed, and compared with the different crystal packing of dimorph 2A. This analysis is made in the context of the polymorphic crystal packing of ferrocene ( 1), and the crystal packing of 1,8-diferrocenyl-octatetrayne, Fc-C4-Fc. In 2B the packing is layered, allowing the Fc groups to be organised in approximately square arrays of well-developed edge-to-face (EF) motifs, very similar to the arrangement in the monoclinic and triclinic polymorphs of ferrocene. The C4 chains are sandwiched between the Fc layers in 2B. The same molecule in 2A is packed with some offset-face-to-face (OFF) motifs between Fc groups, and with a motif in which C4 chains occupy the grooves between cyclopentadienyl rings of Fc. In FcC8Fc the packing is dominated by the C8 chains, surrounded by six molecules, two of which present cyclopentadienyl faces to the C8 chain, and four present the groove in the ferrocenyl group, with no EF or OFF motifs. In this progression of structure types and intermolecular motifs for molecules Fc-Cn-Fc, the members with C4 occur at the transition between the ferrocenyl dominant intermolecular motifs and the Cn chain dominant features. Dimorph 2A is like the longer chain structure, while 2B is like ferrocene.
Hurst, S.K., Cifuentes, M.P., McDonagh, A.M., Humphrey, M.G., Samoc, M., Luther-Davies, B., Asselberghs, I. & Persoons, A. 2002, 'Organometallic complexes for nonlinear optics: Part 25. Quadratic and cubic hyperpolarizabilities of some dipolar and quadrupolar gold and ruthenium complexes', Journal of Organometallic Chemistry, vol. 642, no. NA, pp. 259-267.
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A range of dipolar and quadrupolar gold and ruthenium acetylides have been prepared and their electrochemical (Ru complexes) and nonlinear optical properties assessed; electronic communication between the metal centers diminishes as the ?-delocalizable bridge is lengthened and quadratic NLO merit increases on replacing triarylphosphine by trialkylphosphine. One diruthenium example has the largest two-photon absorption cross-section/molecular weight value observed thus far for an organometallic complex.
Hurst, S.K., Cifuentes, M.P., McDonagh, A.M., Humphrey, M.G., Samoc, M., Luther-Davies, B., Asselberghs, I. & Persoons, A. 2002, 'Organometallic complexes for nonlinear optics. Part 25. Quadratic and cubic hyperpolarizabilities of some dipolar and quadrupolar gold and ruthenium complexes', Journal of Organometallic Chemistry, vol. 642, no. 1-2, pp. 259-267.
The complexes [Au(4-CCC6H4NO2)(L)] [L=PCy3 (1), PMe3 (2)], [(L)Au(-4-CCRCC)Au(L)] [R=C6H4, L=PCy3 (4), PPh3 (5); R=C6H4-4-C6H4, L=PCy3 (7), PPh3 (8)], trans,trans-[RuCl(dppm)2(-4,4-CCC6H4C6H4CC)RuCl(dppm)2] (11), trans-[Ru(X)(Y)(dppe)2] [X=Cl, Y=4-CCC6H4I (12), 4-CCC6H4CCSiMe3 (13); X=CCPh, 4-CCC6H4CCH (14)] and {trans-[Ru(CCPh)(dppe)2]}2(-4,4-CCC6H4CCCCC6H4CC) (15) have been prepared and their electrochemical (Ru complexes) and nonlinear optical properties assessed. Electronic communication between the metal centers in 10, 11 and 15 diminishes as the -delocalizable bridge is lengthened. Quadratic nonlinear optical (NLO) merit increases on replacing triarylphosphine by trialkylphosphine, the relative values Au(4-CCC6H4NO2)(PPh3)<1<3 being observed. Cubic NLO values are small for the gold complexes and much larger for the ruthenium examples. Complex 15 has the largest 2/MWt (two-photon absorption cross-section/molecular weight) value observed thus far for an organometallic complex. &copy; 2002 Elsevier Science B.V. All rights reserved.
Malaun, M., Kowallick, R., McDonagh, A.M., Marcaccio, M., Paul, R.L., Asselberghs, I., Clays, K., Persoons, A., Bildstein, B., Fiorini, C., Nunzi, J.M., Ward, M.D. & McCleverty, J.A. 2002, 'Donor-acceptor complexes incorporating ferrocenes: Spectroelectrochemical characterisation, quadratic hyperpolarisabilities and the effects of oxidising and reducing agents', Journal of the Chemical Society. Dalton Transactions, no. 20, pp. 3025-3038.
The donor-acceptor complexes [Fe(C5H5){C5H4QNHM(NO)(TpMe,Me )X}] {TpMe,Me = tris(3,5-dimethylpyrazolyl)borate; Q = nothing, M = Mo, X = Cl, Br, I; M = W, X = Cl; Q = C6H4, M = Mo, X = Cl, Br, I; M = W, X = Cl; Q = CH=CHC6H4 or N=NC6H4, M = Mo, X = Cl), which contain 16-valence electron metal nitrosyl centres, [Fe(C5H5){C5H4QpyMo(NO)(TpMe,Me )Cl}] (py = 4-pyridyl; Q = CH=CH, CH=CHCO, N=CH and C6H4CH=CH), [Fe(C5Me4H){C5H4CH=CHpyMo(NO)(Tp Me,Me)Cl}] and [Fe(C5Me4H)(C5Me4QpyZ)] {Q = CH=CH or CH=N, Z = Mo(NO)(TpMe,Me)Cl or W(CO)5; Q=2,4-CH=CH(C4H2S)CH=CH, Z = W(CO)s or Me+I-}, some of which contain 17-valence electron molybdenum nitrosyl centres, and [Fe(C5Me4H){C5Me4CH=CH(C4 H2S)CH=CHpy}], have been characterised electrochemically, by their electronic spectra, and spectroelectrochemically: Hyper-Rayleigh scattering was used to determine the first hyperpolarisability, , the data showing that (a) is dependent on the metal in the acceptor fragment, (b) increased when Cl or Br was replaced by I and (c) increased when the number of methyl groups on the cyclopentadienyl rings increased. The -values for comparable complexes containing {Mo(NO)(TpMe,Me)Cl} and {W(CO)5} moieties were similar. Chemical oxidation of the ferrocenyl or chemical reduction of the molybdenum nitrosyl acceptor fragments in selected complexes caused a reduction of between 25% and 100% in the NLO response. X-Ray structural studies of [Fe(C5H5){C5H4NHMo(NO)(TpMe,Me )Cl}] (P1) and [Fe(C5Me4H){C5Me4CH=CHpyMo(NO)(Tp Me,Me)Cl}] (P1) are reported.
Malaun, M., Kowallick, R., McDonagh, A.M., Marcaccio, M., Paul, R.L., Asselberghs, I., Clays, K., Persoons, A., Bildstein, B., Fiorini, C., Nunzi, J., Ward, M.D. & McCleverty, J.A. 2001, 'Donor-acceptor complexes incorporating ferrocenes: spectroelectrochemical characterisation, quadratic hyperpolarisabilities and the effects of oxidising and reducing agents', Journal of the Chemical Society - Dalton Transactions, vol. 20, pp. 3025-3038.
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The donor-acceptor complexes [Fe(C5H5){C5H4QNHM(NO)(TpMe,Me)X}] {TpMe,Me= tris(3,5-dimethylpyrazolyl)borate; Q = nothing, M = Mo, X = Cl, Br, I; M = W, X = Cl; Q = C6H4, M = Mo, X = Cl, Br, I; M = W, X = Cl; Q = CHCHC6H4 or NNC6H4, M = Mo, X = Cl), which contain 16-valence electron metal nitrosyl centres, [Fe(C5H5){C5H4QpyMo(NO)(TpMe,Me)Cl}] (py = 4-pyridyl; Q = CHCH, CHCHCO, NCH and C6H4CHCH), [Fe(C5Me4H){C5H4CHCHpyMo(NO)(TpMe,Me)Cl}] and [Fe(C5Me4H)(C5Me4QpyZ)] {Q = CHCH or CHN, Z = Mo(NO)(TpMe,Me)Cl or W(CO)5; Q2,4-CHCH(C4H2S)CHCH, Z = W(CO)5 or Me+I}, some of which contain 17-valence electron molybdenum nitrosyl centres, and [Fe(C5Me4H){C5Me4CHCH(C4H2S)CHCHpy}], have been characterised electrochemically, by their electronic spectra, and spectroelectrochemically. Hyper-Rayleigh scattering was used to determine the first hyperpolarisability, , the data showing that (a) is dependent on the metal in the acceptor fragment, (b) increased when Cl or Br was replaced by I and (c) increased when the number of methyl groups on the cyclopentadienyl rings increased. The -values for comparable complexes containing {Mo(NO)(TpMe,Me)Cl} and {W(CO)5} moieties were similar. Chemical oxidation of the ferrocenyl or chemical reduction of the molybdenum nitrosyl acceptor fragments in selected complexes caused a reduction of between 25% and 100% in the NLO response. X-Ray structural studies of [Fe(C5H5){C5H4NHMo(NO)(TpMe,Me)Cl}] (P) and [Fe(C5Me4H){C5Me4CHCHpyMo(NO)(TpMe,Me)Cl}] (P) are reported.
McDonagh, A.M., Ward, M.D. & McCleverty, J.A. 2001, 'Redox and UV/VIS/NIR Spectroscopic Properties of Tris(pyrazolyl)borato-oxo-molybdenum(V) Complexes With Naptholate and Related Co-ligands', New Journal of Chemistry, vol. 25, pp. 1236-1244.
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McDonagh, A.M., Deeble, G.J., Hurst, S.K., Cifuentes, M. & Humphrey, M.G. 2001, 'Ruthenium Vinylidene and Acetylide Complexes. An Advanced Undergraduate Multi-technique Inorganic / Organometallic Chemistry Experiment', Journal Of Chemical Education, vol. 78, pp. 232-234.
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McDonagh, A.M., Bayly, S., Riley, D., Ward, M.S., McCleverty, J.A., Cowin, M., Morgan, C.A. & Varrazza, R. 2000, 'A Variable Optical Attenuator Operating In The Near-infrared Region Based On An Electrochromic Molybdenum Complex', Chemistry Of Materials, vol. 12, no. 9, pp. 2523-2524.
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McDonagh, A.M., Lucas, N.T., Cifuentes, M.P., Humphrey, M.G., Houbrechts, S. & Persoons, A. 2000, 'Organometallic Complexes For Nonlinear Optics Part 20. Syntheses And Molecular Quadratic Hyperpolarizabilities Of Alkynyl Complexes Derived From (E)-4,4'-HC=CC6H4N =NC6H4NO2', Journal Of Organometallic Chemistry, vol. 605, no. 2, pp. 193-201.
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The syntheses of the alkyne (E)-4,4?-HC6-point triple bond; length half of m-dashCC6H4N=NC6H4NO2 (1) and alkynyl complexes LnM{(E)-4,4?-C6-point triple bond; length half of m-dashCC6H4N=NC6H4NO2} [LnM=trans-[RuCl(dppm)2] (2), Ru(PPh3)2(?-C5H5) (3), Au(PPh3) (4)] are reported. A structural study of 2 reveals E stereochemistry about the azo-linkage. Electrochemical data for the ruthenium complexes reveal that the azo-linkage in complexes 2 and 3 perturbs the metal-centred oxidation potential compared to all other alkynyl complexes of similar composition. Quadratic optical nonlinearities by hyper-Rayleigh scattering (HRS) at 1064 nm are very large for 2 and 3, but resonance-enhanced. Comparison of HRS data for 4 with those of Au{(E)-4,4?-C6-point triple bond; length half of m-dashCC6H4X=CHC6H4NO2}(Image hImage ) (X=CH, N) reveals that complex 4 has a significantly larger quadratic nonlinearity than its ene- or imino-linked analogues.
McDonagh, A.M., Cifuentes, M.P., Humphrey, M.G., Houbrechts, S., Maes, J., Persoons, A., Samoc, M. & Luther-Davies, B. 2000, 'Organometallic Complexes For Nonlinear Optics Part 21. Syntheses And Quadratic Hyperpolarizabilities Of Alkynyl Complexes Containing Optically Active 1,2-bis(methylphenylphosphino)benzene Ligands', Journal Of Organometallic Chemistry, vol. 610, no. 1-Feb, pp. 71-79.
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The preparation of the chloro complex trans-[FeCl2{(R,R)-diph}2] (1) and the alkynyl complexes trans-[M(4- C=CC6H4R)Cl{(R,R)-diph}2] [M=Fe, R=NO2 (2); M=Ru, RH (4), NO2 (5), (E)-CH=CH-4-C6H4NO2 (6); M=Os, R=NO2 (7)], incorporating the optically active diphosphine 1,2-bis(methylphenylphosphino)benzene (diph), are described. Oxidation potentials, as determined by cyclic voltammetry, increase as 2B7B5. Molecular quadratic nonlinearities by hyper-Rayleigh scattering at 1064 nm increase upon introduction of an acceptor group (4B5), chain-lengthening of bridging group (5B6), and proceeding from 3d to 4d and 5d metal (25557). Two-level-corrected nonlinearities reproduce the first two trends, but metal variation follows the sequence 2B7B5. The experimental and two-level-corrected nonlinearities for 6 (2795x10-30 and 406x10-30 esu, respectively), are amongst the largest observed thus far for organometallic complexes. Crystals of complexes 2 and 7 exhibit second-harmonic generation (assessed using the Kurtz powder technique), with an efficiency for the former of twice that of urea.
delfs, C., Stranger, R., Humphrey, M.G. & McDonagh, A.M. 2000, 'Trends In back-bonding in the Series trans-[M(cC= CR)Cl(PH3)(4)] (M = Fe, Ru, Os R = H, Ph, C6H4NO2-4)', Journal Of Organometallic Chemistry, vol. 607, no. 1-2, pp. 208-212.
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The electronic structure of the complexes trans-[M(C=CR)Cl(PH3)4] (M=Fe, Ru, Os; R=H, Ph, C6H4NO2-4) has been investigated using approximate density functional theory in order to examine the M=C back-bonding interaction. For all three metal systems, the p back-bonding increases in the order R=H<Ph<C6H4-4-NO2, indicating that the p acceptor character of the acetylide ligand increases with the electron-withdrawing ability of the substituent. The inclusion of relativistic effects in the calculations results in a metal dependence of Fe~Ru<Os for the back-bonding, consistent with the observed trend in quadratic hyperpolarizabilities, beta
McDonagh, A.M., Cifuentes, M.P., Lucas, N.T., Humphrey, M.G., Houbrechts, S. & Persoons, A. 2000, 'Organometallic Complexes For Nonlinear Optics Part 19. Syntheses And Molecular Quadratic Hyperpolarizabilities Of Indoanilino-alkynyl-ruthenium Complexes', Journal Of Organometallic Chemistry, vol. 605, no. 2, pp. 184-192.
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The terminal alkyne 4-HC6-point triple bond; length half of m-dashCC6H4N=Image H (1) and ruthenium complex derivatives trans-[Ru(C6-point triple bond; length half of m-dashC-4-C6H4N= Image Full-size image H}Cl(dppm)2] (2) and [Ru{C6-point triple bond; length half of m-dashC-4-C6H4N=Image H}(PPh3)2(?-C5H5)] (3) have been synthesized. An X-ray structural study of 3 reveals the expected equivalent C---C bond lengths of the phenyl and alternating C---C and C=C bond lengths of the quinonal ring in the indoanilinoalkynyl ligand; there is a dihedral angle of 47.59&deg; between the phenyl and quinonal rings, probably a result of ortho-hydrogen repulsion. Metal-centred oxidation potentials of 2 and 3 are similar to those of `extended chain 4-nitroarylalkynyl complex analogues. Irreversible quinonal ring-centred reductions occur at significantly more negative potentials than the quasi-reversible reductions in their nitro-containing analogues. Quadratic optical nonlinearities by hyper-Rayleigh scattering at 1064 nm for 2 (41710-30 esu) and 3 (65810-30 esu) are both large, but resonance enhanced. Two-level-corrected nonlinearities for these complexes (12410-30, 15910-30 esu, respectively) are also large, despite the presence of electron-donating tert-butyl groups reducing the efficiency of the (formally) electron-accepting quinonal ring in these donor-bridge-acceptor complexes
McDonagh, A.M., Cifuentes, M.P., Lucas, N.T., Humphrey, M.G., Houbrechts, S. & Persoons, A. 2000, 'Organometallic complexes for nonlinear optics: Part 19. Syntheses and molecular quadratic hyperpolarizabilities of indoanilino-alkynyl-ruthenium complexes', Journal of Organometallic Chemistry, vol. 605, no. 2, pp. 193-201.
The terminal alkyne 4-HCCC6H4N=CCH=CtBuC(O)CtBu=CH (1) and ruthenium complex derivatives trans-[Ru(CC-4-C6H4N=CCH=CtBuC(O)C tBu=CH}Cl(dppm)2] (2) and [Ru{CC-4-C6H4N=CCH=CtBuC(O)C tBu=CH}(PPh3)2(-C5H 5)] (3) have been synthesized. An X-ray structural study of 3 reveals the expected equivalent C-C bond lengths of the phenyl and alternating C-C and C=C bond lengths of the quinonal ring in the indoanilino-alkynyl ligand; there is a dihedral angle of 47.59&deg; between the phenyl and quinonal rings, probably a result of ortho-hydrogen repulsion. Metal-centred oxidation potentials of 2 and 3 are similar to those of 'extended chain' 4-nitroaryl-alkynyl complex analogues. Irreversible quinonal ring-centred reductions occur at significantly more negative potentials than the quasi-reversible reductions in their nitro-containing analogues. Quadratic optical nonlinearities by hyper-Rayleigh scattering at 1064 nm for 2 (41710-30 esu) and 3 (65810-30 esu) are both large, but resonance enhanced. Two-level-corrected nonlinearities for these complexes (12410-30, 15910-30 esu, respectively) are also large, despite the presence of electron-donating tert-butyl groups reducing the efficiency of the (formally) electron-accepting quinonal ring in these donor-bridge-acceptor complexes. &copy; 2000 Elsevier Science S.A.
McDonagh, A.M., Lucas, N.T., Cifuentes, M.P., Humphrey, M.G., Houbrechts, S. & Persoons, A. 2000, 'Organometallic complexes for nonlinear optics: Part 20. Syntheses and molecular quadratic hyperpolarizabilities of alkynyl complexes derived from (E)-4,4-HCCC6H4N=NC6H4NO 2', Journal of Organometallic Chemistry, vol. 605, no. 2, pp. 184-192.
The syntheses of the alkyne (E)-4,4-HCCC6H4N=NC6H4NO 2 (1) and alkynyl complexes LnM{(E)-4,4-CCC6H4N=NC6H 4NO2} [LnM=trans-[RuCl(dppm)2] (2), Ru(PPh3)2(-C5H5) (3), Au(PPh3) (4)] are reported. A structural study of 2 reveals E stereochemistry about the azo-linkage. Electrochemical data for the ruthenium complexes reveal that the azo-linkage in complexes 2 and 3 perturbs the metal-centred oxidation potential compared to all other alkynyl complexes of similar composition. Quadratic optical nonlinearities by hyper-Rayleigh scattering (HRS) at 1064 nm are very large for 2 and 3, but resonance-enhanced. Comparison of HRS data for 4 with those of Au{(E)-4,4-CCC6H4X=CHC6H 4NO2}(PPh3) (X=CH, N) reveals that complex 4 has a significantly larger quadratic nonlinearity than its ene- or imino-linked analogues. &copy; 2000 Elsevier Science S.A.
McDonagh, A.M., Cifuentes, M.P., Humphrey, M.G., Houbrechts, S., Maes, J., Persoons, A., Samoc, M. & Luther-Davies, B. 2000, 'Organometallic complexes for nonlinear optics Part 21. Syntheses and quadratic hyperpolarizabilities of alkynyl complexes containing optically active 1,2-bis(methylphenylphosphino)benzene ligands', Journal of Organometallic Chemistry, vol. 610, no. 1-2, pp. 71-79.
The preparation of the chloro complex trans-[FeCl2{(R,R)-diph}2] (1) and the alkynyl complexes trans-[M(4-CCC6H4R)Cl{(R,R)-diph}2] [M = Fe, R = NO2 (2); M = Ru, R = H (4), NO2 (5), (E)-CH=CH-4-C6H4NO2 (6); M = Os, R = NO2 (7)], incorporating the optically active diphosphine 1,2-bis(methylphenylphosphino)benzene (diph), are described. Oxidation potentials, as determined by cyclic voltammetry, increase as 2 < 7 < 5. Molecular quadratic nonlinearities by hyper-Rayleigh scattering at 1064 nm increase upon introduction of an acceptor group (4 < 5), chain-lengthening of bridging group (5 < 6), and proceeding from 3d to 4d and 5d metal (2 5 7). Two-level-corrected nonlinearities reproduce the first two trends, but metal variation follows the sequence 2 < 7 < 5. The experimental and two-level-corrected nonlinearities for 6 (2795 10-30 and 406 10-30 esu, respectively), are amongst the largest observed thus far for organometallic complexes. Crystals of complexes 2 and 7 exhibit second-harmonic generation (assessed using the Kurtz powder technique), with an efficiency for the former of twice that of urea. &copy; 2000 Elsevier Science S.A. All rights reserved.
McDonagh, A.M., Humphrey, M.G., Samoc, M., Luther-Davies, B., Houbrechts, S., Wada, T. & Sasabe, H. 1999, 'Organometallic Complexes For Nonlinear Optics. 16. Second And Third Order Optical Nonlinearities Of Octopolar Alkynylruthenium Complexes', Journal Of The American Chemical Society, vol. 121, no. 6, pp. 1405-1406.
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McDonagh, A.M., Humphrey, M.G., Samoc, M. & Luther-Davies, B. 1999, 'Organometallic Complexes For Nonlinear Optics. 17. Synthesis, Third-order Optical Nonlinearities And Two-photon Absorption Cross Section Of An Alkynylruthenium Dendrimer', Organometallics, vol. 18, no. 25, pp. 5195-5197.
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A soluble, oxidatively and thermally very stable alkynylruthenium dendrimer 1,3,5-C6H3(4-CCC6H4CC-trans-[Ru(dppe)2]CC-3,5-C6H3-{4-CCC6H4CC-trans-[Ru(CCPh)(dppe)2]}2)3, containing a large two-dimensional -delocalized system, has been prepared using an experimentally straightforward convergent synthetic approach. The first third-order nonlinear optical (NLO) measurements of an organometallic dendrimer have been obtained using the Z-scan technique at a wavelength of 800 nm. Progression from 1,3,5-C6H3(4-CCC6H4CC-trans-[Ru(dppe)2]CCPh)3 to the dendrimer results in (i) no loss of optical transparency, (ii) an increase in the second hyperpolarizability, , which is proportionately greater than either the increase in the number of phenylethynyl groups or the extinction coefficient for the important MLCT band, and (iii) a dramatic enhancement of two-photon absorption.
Whittall, I., McDonagh, A.M., Humphrey, M.G. & Samoc, M. 1999, 'Organometallic Complexes In Nonlinear Optics Ii Third-order Nonlinearities And Optical Limiting Studies', Advances In Organometallic Chemistry, Vol 43, vol. 43, pp. 349-405.
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Houbrechts, S., Wada, T., Sasabe, H., Morrall, J.P., Whittall, I.R., McDonagh, A.M., Humphrey, M.G. & Persoons, A. 1999, 'Novel organometals for nonlinear optics: Octopolar alkynylmetal complexes', Molecular Crystals and Liquid crystals, vol. 22, pp. 165-168.
The quadratic hyperpolarizabilities as determined by hyper-Rayleigh scattering are reported for a series of silicon and metal (gold and ruthenium) alkynyl complexes with dipolar or octopolar symmetry.
McDonagh, A.M., Humphrey, M.G. & Hockless, D. 1998, 'Preparation Of Cis- And Trans-(oscl2(me2so)(4)), And X-ray Crystal Structures Of The All-s-bound Isomers', Australian Journal Of Chemistry, vol. 51, no. 9, pp. 807-811.
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Naulty, R., McDonagh, A.M., Whittall, I., Cifuentes, M.P., Humphrey, M.G., Houbrechts, S. & Maes, J. 1998, 'Organometallic Complexes For Nonlinear Optics. 15. Molecular Quadratic Hyperpolarizabilities Of Trans-bisbis(diphenylphosphino)methane)ruthenium Sigma-aryl- And Sigma-pyridyl-acetylides X-ray Crystal Structure Of Trans-(ru(2-c Cc5h3n-5-no2)cl(dppm)(', Journal Of Organometallic Chemistry, vol. 563, no. 1-Feb, pp. 137-146.
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Whittall, I., McDonagh, A.M., Humphrey, M.G., Samoc, M. & Persoons, A. 1998, 'Organometallic Complexes In Nonlinear Optics I Second-order Nonlinearities', Advances In Organometallic Chemistry, Vol 42, vol. 42, pp. 291-362.
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Naulty, R.H., McDonagh, A.M., Whittalla, I.R., Cifuentes, M.P., Humphrey, M.G., Houbrechts, S., Maes, J., Persoons, A., Heath, G.A. & Hockless, D.C.R. 1998, 'Organometallic complexes for nonlinear optics. 15. Molecular quadratic hyperpolarizabilities of trans -bis {bis(diphenylphosphino)methane}ruthenium -aryl- And -pyridyl-acetylides: X-ray crystal structure of trans-[Ru(2-C=CC5H3N-5-NO2)Cl(dppm) 2]', Journal of Organometallic Chemistry, vol. 563, no. 1-2, pp. 137-146.
The complexes trans-[Ru(2-CCC5H3N-5-R)Cl(dppm)2] [R = H (6), NO2 (7)] have been prepared and 7 has been structurally characterized; comparison with the structural study of trans-[Ru(4-CCC6H4NO2)Cl(dppm) 2] (3) reveals a decrease in Ru-C(1) distance and increase in Ru-Cl(1) distance, consistent with stronger -bonding by the nitropyridylalkynyl ligand in 7 compared to the nitrophenylalkynyl ligand in 3. Electrochemical data for 3, 6, 7, precursor dichloro complexes [RuCl2(dppm)2] [cis (1a), trans (1b)], and related alkynyl complexes trans-[Ru(4-CCC6H4R)Cl(dppm)2] [R = H (2), 4-C6H4NO2 (4), (E)-4-CH=CHC6H4NO2 (5)] have been determined by cyclic voltammetry. Introduction of nitro substituent in progressing from 2 to 3 or 6 to 7 leads to a substantial increase in EoRuII/III, most of which is lost on chain-lengthening the alkynyl ligand in progressing from 3 to 4 or 5. Replacement of phenyl by pyridyl in progressing from 2 to 6 or 3 to 7 results in a 0.1 V increase in EoRuII/III. The optical spectra of representative complexes have been examined. Introduction of a nitro substituent onto the phenylalkynyl ligand, in progressing from 2 to 3, results in a substantial (ca. 11000 cm-1) red-shift in the intense MLCT band of the RuII-CC-Ar-NO2 moiety. Complexes 3, 4 and 5 exhibit sizable solvatochromic shifts, suggestive of significant optical nonlinearities. Quadratic hyperpolarizabilities for 2-7 were determined by hyper-Rayleigh scattering (HRS) at 1064 nm; measurements are consistent with an increase in HRS upon incorporation of nitro substituent (progressing from 2 to 3 or 6 to 7), chain-lengthening the alkynyl ligand (progressing from 3 to 4 and then to 5) and replacing phenyl by pyridyl in progressing from 2 to 6, general trends that are maintained with the two-level-corrected data, and which parallel shifts in max to low energy. The observed and two-level-corrected HRS values for 7 are lower than expected; it is perhaps significant that max for 7 is close to ...
McDonagh, A.M., Humphrey, M.G. & Hockless, D. 1997, 'Selective Preparation Of Cis- Or Trans-dichlorobis(r,r)-1,2-phenylenebis(methylphenylphosphine-p))osmium(ii) From Dimethylsulfoxide Complex Precursors', Tetrahedron-asymmetry, vol. 8, no. 21, pp. 3579-3583.
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McDonagh, A.M., Cifuentes, M.P., Whittall, I., Humphrey, M.G., Samoc, M., Luther-Davies, B. & Hockless, D. 1996, 'Organometallic Complexes For Non-linear Optics .7. Cubic Optical Non-linearities Of Octahedral Trans-bisbis(diphenylphosphino)methane)ruthenium Acetylide Complexes; X-ray Crystal Structure Of Trans-(ru(c Cph)(4-c Cc6h4no2)(dppm)(2))', Journal Of Organometallic Chemistry, vol. 526, no. 1, pp. 99-103.
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McDonagh, A.M., Whittall, I., Humphrey, M.G., Hockless, D., Skelton, B. & White, A.S. 1996, 'Organometallic Complexes For Nonlinear Optics .6. Syntheses Of Rigid-rod Ruthenium Sigma-acetylide Complexes Bearing Strong Acceptor Ligands; X-ray Crystal Structures Of Trans-(ru(c Cc6h4no2-4)(2)(dppm)(2)) And Trans-(ru(c Cc6h4c6h4no2-4,4)(2)(dppm)(', Journal Of Organometallic Chemistry, vol. 523, no. 1, pp. 33-40.
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Hockless, D., Wild, S., McDonagh, A.M., Whittall, I. & Humphrey, M.G. 1996, 'Trans-dichlorobis((r,r)-1,2-phenylenebis-(methylphenylphosphine-p))ruthenium(ii)', Acta Crystallographica Section C-crystal Structure Communications, vol. 52, pp. 1639-1641.
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McDonagh, A.M., Whittall, I., Humphrey, M.G., Skelton, B. & White, A.S. 1996, 'Organometallic Complexes For Non-linear Optics .5. Syntheses And Computationally-derived Quadratic Non-linearities Of Trans-(ru(c Cc(6)h(4)r-4)cl(dppm)(2))(r eh, No2, C6h4no2-4, Ch chc6h4no2-4,(e)); X-ray Crystal Structure Of Trans-(ru(c Cc6h4c6h4no2', Journal Of Organometallic Chemistry, vol. 519, no. 1-Feb, pp. 229-235.
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McDonagh, A.M., Whittall, I.R., Humphrey, M.G., Skelton, B.W. & White, A.H. 1996, 'Organometallic complexes for non-linear optics V : Syntheses and computationally-derived quadratic non-linearities of trans-[Ru(CCC6H4R-4)Cl(dppm) 2] (R = H, NO2, C6H4NO2-4, CHCHC6H4N02-4,( E));', Journal of Organometallic Chemistry, vol. 519, no. 1-2, pp. 229-235.
A series of systematically-varied donor-acceptor octahedral ruthenium -acetylide complexes of general formula trans-[Ru(CCC6H4R-4)Cl(dppm)2] (R = H, NO2, C6H4NO2-4 CHCHC6H4NO2-4,(E)) has been synthesized. An X-ray structural study of trans- [Ru(CCC6H4C6H4NO 2-4,4')Cl(dppm)2] reveals non-planarity of the biphenylene moiety in the solid state. Semi-empirical calculations employing ZINDO were performed on the acetylide complexes and the dichloro species cis- and trans-[RuCl2(dppm)2] to evaluate molecular quadratic optical non-linearities, ; the results are consistent with (a) a significant increase in upon incorporation of a strong acceptor substituent, (b) a substantial increase in on chain lengthening, and (c) a 50% decrease in non-linearity upon rotation of phenylene-phenylene dihedral angle from coplanarity to orthogonality for the structurally-characterized complex. &copy; 1996 Elsevier Science S.A.