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Postgraduate and honours research projects - X-ray absorption spectroscopyProjects in the Spiccia laboratorySolar water splitting for renewable hydrogen productionProf L Spiccia and Dr Annette Koo (School of Chemistry) Dr Rosalie Hocking (Monash Centre for Synchrotron Science) With global oil supplies becoming increasingly inaccessible and atmospheric carbon levels rising at an alarming rate, development of a sustainable alternative transport fuel is essential. Hydrogen (H2) is a favorable alternative due to its dynamic application potential and its low atmospheric impact. Ideally, hydrogen would be produced from the splitting of water. This is currently energy intensive (typically achieved by electrolysis) and limited by cost. The photolysis of water is the most promising renewable source of hydrogen, but water photo-oxidizing catalyst are lacking. We have developed an efficient water oxidation catalyst, based on a manganese cubane cluster, which combines features of photosynthetic enzymes with the light harvesting power of dye-sensitized solar cells. Paired with a proton reducing catalytic cathode, we have produced a photoelectrochemical cell that produces pure H2 and O2 from water and sunlight. In this project, Synchrotron techniques including X-ray Absorption Spectroscopy will be used in an effort to establish the active species and the mechanism by which water oxidation catalysis is achieved so that catalyst design and device performance can be optimized. This project is in collaboration with Professor Dismukes (Princeton University) and Dr Swiegers (CSIRO). Bioconjugates for application in neuroscience - Alzheimer's disease
Prof L Spiccia (School of Chemistry) As the Australian population ages, Alzheimer's disease is set to reach epidemic proportions. By 2040, 500,000 Australians will have this disease, a disorder characterized by the progressive loss of memory and other faculties. Already, dementia costs $6.6 billion per year in Australia. This project aims to develop new biomarkers for Alzheimer's disease. This will confer a number of benefits, allowing patients to be diagnosed and staged, and allowing pre-symptomatic identification of patients and monitoring of treatment effects. The characteristic pathologic feature of Alzheimer's disease is the neuritic plaque comprising Aβ amyloid and neurofibrillary tangles made of paired helical fragment (PHF)-tau aggregates. The current view is that the amyloid precursor protein (APP) contains an Aβ region which, if metabolized incorrectly by enzymes, generates a β-amyloid peptide (Aβ) that can aggregate into fibrils. The Aβ peptide contains a histidine rich region which can bind strongly to metal ions, such as copper(II) and zinc(II), and this process may promote aggregation. In this project, we aim to develop Cu-64 radio-labeled imaging agents which can cross the blood brain barrier and bind β-amyloid peptide (Aβ). Synchrotron techniques including X-ray Absorption Spectroscopy will be used extensively to study the binding of our non-radiolabelled agents to the β-amyloid peptides in vitro prior to their application in vivo. For further information please contact:
Professor L Spiccia Projects in the Jones laboratoryIn the past 5 years remarkable progress has been made in the chemistry of low oxidation state and low coordination number p-block compounds. It is now possible to prepare and investigate the fascinating reactivity of compounds that were thought incapable of existence until a few years ago. This area is rapidly expanding in the US and Europe but is under-studied in Australia. Heterocyclic gallium(I) donors: analogues of N-heterocyclic carbenesN-heterocyclic carbenes (NHCs) (i.e. :C{N(R)C(H)}2) have emerged as one of the most important ligand classes used in coordination chemistry in the last decade. Their metal complexes have found wide application in many areas of catalysis, a field which partly led to the award of the 2005 Nobel prize in chemistry. We have recently developed routes to two gallium(I) analogues of NHCs, 1 and 2, which have a lone pair at gallium and, counterintuitively, can act as Lewis bases through a metal centre that is normally classed as a Lewis acid. Many gallium-metal complexes of these ligands have been prepared in the past 3 years (e.g. see picture) which are now finding application in organic synthetic methodologies (cf. NHC complexes). You will prepare examples of such complexes and investigate the degree of Ga-M π-bonding they exhibit utilising Metal L-edge X-ray Absorption Spectroscopy available on the soft x-ray beam-line at the Australian Synchrotron. As part of an integrated approach to this work you will also have the opportunity to apply Density Functional Theory (DFT) to the analysis of this bonding for comparison with experimental results. see for eg. (i) P.L. Arnold, S.T. Liddle, J. McMaster, C. Jones and D.P. Mills, J. Am. Chem. Soc., 2007, 129, 5360; (ii) C. Jones, P.C. Junk, J.A. Platts and A. Stasch, J. Am. Chem. Soc., 2006, 128, 2206, (iii) R.J. Baker and C. Jones, Coord. Chem. Revs., 2005, 249, 1857. The chemistry of methyl phosphaalkyne (PCMe)Compounds containing P-C triple bonds (phosphaalkynes) were thought incapable of existence until 1991. Since that time the chemistry of sterically stabilised examples (e.g. PCBut) has led to over 500 reports in the literature. In the last year we have shown that steric stabilisation is not a prerequisite for the stability of these compounds and have reported the first chemistry of methyl phosphaalkyne (PCMe), the P-analogue of propyne. The coordination and oligomerisation of this new ligand has led to a variety of organophosphorus and phospha-organometallic cage complexes and polymers which display unusual optical, electronic and charge storage properties. You will use synchrotron based spectroscopy (e.g.P K-edge XAS), available at the NSRRC in Taiwan and Fe K-edge XAS available at the Australian synchrotron. see (i) C. Jones, C. Schulten and A. Stasch, Dalton Trans., 2007, 1929; (ii) C. Jones, C. Schulten and A. Stasch, Dalton Trans., 2006, 3733 Stabilisation and application of novel low oxidation state metal heterocyclesThrough our work on the stabilisation of novel gallium(I) heterocycles we have found that the bulky guanidinate ligands developed to access these compounds can be applied to the preparation of previously inaccessible heterocycles containing low oxidation state metal centres from across the periodic table (e.g. see picture). We have subsequently discovered that these highly reactive compounds have enormous potential to be applied to, for example, small molecule activation, catalysis and enzyme mimicry. You will probe oxidation state of these novel complexes using a combination of X-ray Absorption Spectroscopy (XAS) and X-ray Photoelectron Spectroscopy (XPS) available at the Australian Synchrotron. The results of this study will allow us tailor and enhance the catalytic and other properties of the second generation of these complexes. see (i), S.P. Green, C. Jones and A. Stasch, Science, 2007, 318, 1754, (ii) S.P. Green, C. Jones, P.C. Junk, K.-A. Lippert, and A. Stasch, Chem. Commun., 2006, 3978; (iii) S.P. Green, C. Jones and A. Stasch, Inorg. Chem., 2007, 46, 11. For further information please contact:
Professor Cameron Jones Applications of Synchrotron Science in Geomechanics Research at Monash UniversityCation Exchange Dynamics in BentonitesDr Will Gates, Associate Professor Abdelmalek Bouazza (Department of Civil Engineering, Faculty of Engineering) Bentonites are widely used as inexpensive, yet highly efficient hydraulic barriers for containment of waste leachates, industrial process wastes and mineral ore liquor storage. The form of bentonite, i.e., the type of exchange cation dominating the exchange complex, strongly influences hydraulic performance, and cation exchange can cause changes to hydraulic conductivity with a detrimental effect on the performance of waste barrier systems . The purpose of this research is to improve the chemical resistivity of sodium bentonites against the detrimental effects of highly saline and metaliferous industrial liquors, leachates and wastewaters, thereby minimizing environmental contamination of ground and surface water. Synchrotron based spectroscopies and spectromicroscopies will be applied to develop modifications that enhance the chemical resistance, yet maintain the engineering performance of sodium bentonite barrier systems. For further information please contact:
Dr Will Gates
Associate Professor Abdelmalek Bouazza Bio-mineralization Enhancement of Engineered SoilsAssociate Professor Abdelmalek Bouazza, Dr Will Gates, Dr Ranjith Pathegama Gamage (Department of Civil Engineering, Faculty of Engineering) Naturally occurring pore filling reactions in soils and sediments, mediated by bacteria, have strong potential in design of engineered load bearing structures and environmental barriers. Examples of natural bio-precipitation reactions include calcrete in desert soils, or of silcrete in desert rocks and soils. This research aims to promote bio-mineral reactions to improve the load-bearing capacity, as well as lowering the hydraulic conductivity soils, sediments and rocks. A variety of spectroscopic and microscopic tools, including synchrotron based tools, as well as traditional geomechanics and geotechnical engineering tools, will be employed to address bio-mineralisation reactions. For further information please contact:
Associate Professor Abdelmalek Bouazza
Dr Will Gates
Dr Ranjith Pathegama Gamage Honours project: catalytic oxidations of minerals (bioleaching)Dr Rosalie Hocking (Monash Centre for Synchrotron Science) The extraction of metal sulfide minerals industrially involves three fundamental processes. First, metal sulfides are separated from each other and the unwanted minerals in the ore (gangue); secondly, each sulfide concentrate is oxidatively leached to extract the metal; and finally the leachate is electro-refined. Out of these three stages of mineral processing, the leaching process attracts the most attention because it has both environmental and economic implications. Sulfide minerals are insoluble in water or acid solution unless they are first oxidised. While the oxidation of sulfide minerals will occur in air the process can be very slow, and commercial mining operations are increasingly considering the exploitation of bacteria to catalyse the oxidation of the metal sulfides to metal sulfates and sulfuric acid. While stoichiometrically simple, many problems exist in the implementation of these processes, particularly the ability to control the rate of these reactions; in some cases, the leaching process slows or stops, whilst in others the reaction may continue where it is not wanted. Slowing of the leaching process is not understood well but it is thought that the chemistry on the surface of the mineral may play an important role in both catalyzing the reaction and in the formation of species to which the bacteria cannot penetrate. Projects focus on examination of ways to both improve the leaching process and to understand the catalytic mechanisms at work. Spectroscopic approaches including X-ray Absorption Spectroscopy will be utilized to follow the reactions in situ. These observations will be combined with computational approaches to both interpret the spectrum and model the reactions. Links to the mechanistic chemistry of similar systems including the Fe-S redox chemistry of the environment, and Fe-S clusters important in metalloenzymes will be examined. For further information contact:
Dr Rosalie Hocking |