Brochure
Dr Mark A. Fox
E-mail: [email protected]
Boron-Nitrogen-Carbon Chemistry
Boron, when paired with nitrogen, forms many compounds that have molecular structures like those of familiar carbon (organic) compounds. However, by itself or when paired with metals, carbon or hydrogen, boron forms intricate robust polyhedral structures including metal borides and boron carbide which are very hard thermally stable materials. Therefore we are investigating BCN compounds, both ring (organic) and polyhedral types, to gain insight into the fundamental science and in the hope that interesting new molecules and useful new materials may result. Derivatives of borazine B3N3H6 can be prepared directly from commercially available boron hydrides and organonitrogen compounds. Such substances can be used as precursors from which to prepare BCN analogues of diamond and graphite, the long familiar forms of carbon and boron nitride.[1] Syntheses and thermolyses of air- and moisture-sensitive gases, liquids and solids are generally carried out with vacuum lines and glove boxes in this area.
Icosahedral Borane and Carborane Chemistry
We are opening up the derivative chemistry of icosahedral boranes (B12H122-) and carboranes (C2B10H12). Potential applications of these derivatives are
a) High temperature polymers and ceramics [2]
b) Tumour-targeting agents in boron neutron capture therapy (BNCT)
c) X-ray constrast agents
d) Liquid crystals
e) Crystal engineering.
We are currently developing new routes to carboranes with C2B9 cages.[3] These are well known precursors to a vast array of metallacarboranes (see Dr A.K. Hughes’ research for example) with potential applications in
a) Catalysis
b) Metal extraction agents.
Syntheses of these air-stable derivatives are often carried out with vacuum lines. These derivatives are usually characterized by solution-state multinuclear NMR spectroscopy (including the very useful 2D 11B-11B{1H} COSY and 1H{11B selective} techniques).
Ab initio/NMR computations
Fully optimized geometries (at the MP2/6-31G* level) can be regarded as excellent representations of molecular structures found experimentally in the gas phase and in solution for boranes, carboranes and heteroboranes. These geometries are also in very good agreement with geometries determined by X-ray and neutron diffraction where intermolecular forces are not significant. If NMR shifts (usually 11B) computed at the DFT-GIAO level from one MP2-optimized geometry for a compound show a very good correlation with its experimental solution-state NMR data then the optimized geometry is considered the best representation of its molecular structure in solution. This excellent structural determination method is essential to our research.[4]
References
1. R. Brydson, H. Daniels, M. A. Fox,R. Greatrex and C. Workman, Chem. Commun., 2002, 718-719.
2. M.A. Fox and K. Wade, J. Mater. Chem., 2002, 12, 1301-1306.
3. M.A. Fox, A.E. Goeta, A.K. Hughes and A.L. Johnson, J. Chem. Soc., Dalton Trans., 2002, 2132-2141.
4. A. S. Batsanov, M. A. Fox, A. E. Goeta, J. A. K. Howard, A. K. Hughes and J. M. Malget, J. Chem. Soc., Dalton Trans., 2002, 2624-2631.