UCL Chemistry

The ability of some organometallic compounds to form agostic bonds has been first recognises by M.L.H. Green and M. Brookhard in 1983. In this perspective contribution, a more personal look of how this area has developed over the last decades is reported.

This paper describes the use of combinatorial aerosol-assisted chemical vapour deposition (cAACVD) to deposit gallium-doped indium oxide thin films. The oxide films, Ga_xIn_2-xO₃, were deposited within composition graduated films from the aerosol-assisted CVD of GaMe₃, InMe₃ and HOCH₂CH₂OMe. Amorphous Ga₂O₃ was deposited closest to the inlet from the bubbler containing GaMe₃/HOCH₂CH₂OMe whereas crystalline In₂O₃ was grown on the substrate closest to the inlet from the bubbler containing InMe₃/HOCH₂CH₂OMe. A range of gallium-indium-oxide compositions, Ga_xIn_2-xO₃, were deposited on the substrate in the region between the two inlets. This allowed for a systematic investigation on the effect of doping on gallium and indium oxide and a direct relationship between composition and conductivity of the films was observed. This new technique combines the advantages of AACVD (volatility/thermal stability restrictions are removed) with those of cAPCVD/cLPCVD (rapid deposition/analysis of a compositional gradient). By utilizing a liquid-gas aerosol, as is employed in combinatorial AACVD, the restrictions of volatility and thermal stability are lifted and so new precursors and materials can be investigated.

Computer simulations reveal in the most exquisite detail how salt crystals dissolve in water.

Salt dissolution has a resonance with scientists and non-scientists alike being a piece of “chemistry” exploited daily to inhibit the freezing or accelerate the boiling of water. Despite this key role and increased contemporary drivers from e.g. nanotechnology and the desalination industry, the mechanism of salt dissolution has however remained elusive.

Highlight of a paper by Professor Angelos Michaelides and Dr Ben Slater

Computer simulations provide a molecule’s eye view of the melting of ice nanoparticles, predicting melting at very low temperatures.

Drs Schiffmann, Cora and Slater, in collaboration with partners at the University of Liverpool and Cambridge, report in Nature how structures of the emerging class of nanoporous cage materials can predicted using computer simulation techniques.

The paper details the groups most recent developments of the nitro-Mannich reaction. In this paper the observation that the three-component coupling reaction between imines, nitro alkenes, and diakylzincs was heterogeneous in diethyl ether led to the formation of either of two diastereoisomers by judicious choice of solvent. The reaction forms 2 carbon-carbon bonds and controls 3 contiguous stereocentres in one reaction vessel.

In a paper published in Proceedings of the National Academy of Sciences Xinzheng Li, Brent Walker, and Angelos Michaelides solve a 50 year puzzle about the quantum nature of hydrogen bonds.

The researchers have applied state of the art electronic structure techniques, based on hybrid exchange-functionals in DFT and periodic boundary conditions, to unravel the reaction mechanism responsible for the initial stages of the aerobic oxidation of hydrocarbons catalyzed by Mn-doped aluminophosphates.

Work from a perspective article on the theory of cerium  on gold from Angelos Michaelides' group (done in collaboration with Stephen Jenkins from the University of Cambridge and Changjun Zhang) has featured on the cover of Physical Chemistry Chemical Physics (PCCP).