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Postgraduate and honours research projects - small molecule X-ray and powder diffractionInorganic molecular magnetic materials of the nanosized cluster and extended framework typesProf Keith Murray (School of Chemistry) Dr Stuart Batten (School of Chemistry) This project deals with the design, synthesis, crystal structures and detailed magnetic properties of molecular based magnetic materials of two general kinds. The first type deals with medium to large clusters of manganese, iron or vanadium that display single molecule magnetism (SMM), the first such reported example being the oxo-/carboxylato-bridged {Mn(III)/Mn(IV)}12-acetate. These materials display unique, quantum type behaviour in their DC magnetization loops and their AC susceptibility frequency-dependent behaviour. They are much studied in the context of nanomagnetic materials and offer scope in future data storage applications. Recently we discovered tetranuclear Mn(II)/Mn(III) SMMs that contained flexible triethanolamine chelating 'outer' ligands1. The present project aims to make new clusters SMMs of Mn, Fe or V, sometimes combined with lanthanide ions, using a variety of new bridging and terminal ligand groups. It will suit candidates that enjoy inorganic coordination chemistry synthesis, structural and physicochemical studies (we have access to EPR and Mossbauer methods with colleagues in Physics). The other area is the very topical one of d-block coordination polymers of the extended framework type, some displaying functions such as nanoporosity and, in a separate project, spin-crossover. Our work on metal dicyanamide frameworks2, [M(N(CN)2)2], gave rise to a worldwide study of such long-range magnetically ordered compounds and allowed comparisons to be made with the much studied CN- and C2O42- -bridged materials. The present project will concentrate on designing and synthesizing new or little studied types of bridged species, with emphasis on organopolynitriles3 and carbonate and related anions, some being free radical in character. The work is supported by a new ARC Discovery grant. It is possible that two scholarships will be available, and both projects will involve the use of X-ray crystallography for structure determination, both laboratory based and at the Australian Synchrotron.
1. L. M. Wittick, K. S. Murray, B. Moubaraki, S. R. Batten, L. Spiccia, K. J. Berry, Dalton Trans. 2004, 1003. For further information please contact:
Professor Keith Murray
Dr Stuart Batten Metallosupramolecules and coordination polymers with azamacrocycles and crownsDr Stuart Batten (School of Chemistry) The aim of this project is to produce new organic ligands based on the TACN, crown and cyclam macrocycles, and then use these ligands to construct new coordination polymers and metallosupramolecules, such as the one shown here (the structure of which was solved at the APS synchrotron in Chicago). These ligands contain an interior binding site (the macrocycle), and peripheral coordination sites. It is intended that the later sites will bind to metal atoms, producing either infinite (coordination polymers) or finite assemblies (metallosupramolecules), depending on choice of metal and coligand. These ligands therefore offer the potential for novel assemblies that may show interesting properties such as spin-crossover (molecular switching or sensing), microporosity (including gas storage), and catalytic applications. The crown based ligands have already been shown to display variable bridging lengths depending on the presence of alkali metals or other guests, and thus revolutionary new materials are envisaged which open and close their pores by e.g. soaking in salt water. This project will involve aspects of organic and inorganic synthesis, X-ray crystallography and other characterization techniques. The crystallography will be performed using both laboratory facilities and the Australian Synchrotron. Beamlines involved will include the single crystal and powder diffraction beamlines, however it is likely that other beamline techniques may also be used. For further information please contact:
Dr Stuart Batten |