Ashoka G Samuelson
Articles written in Journal of Chemical Sciences
Volume 108 Issue 3 June 1996 pp 131-142 Modern Trends In Inorganic Chemistry
Metal-metal distances in polynuclear metal complexes are often controlled by factors other than favourable metal-metal (M-M) interactions. Recently metal cluster topology has been identified as a major factor in controlling Cu-Cu distances in tetrahedral copper clusters. The more obvious ligand control in M-M distances was shown to play a secondary role. In order to probe ways to tune metal-metal distances in clusters, a study of clusters with similar ligands around the metal has been taken up. Two broad classes were identified: Clusters in which there are two-electron two-centre bonds, and a second class where multicentre multielectron bridging is involved.
Clusters held together by two-electron two-centre bonds can be analysed fairly effectively using a test electrophile like the proton. This is illustrated by analysing structures available in the literature. The sensitivity of the method to detect M-M interactions will be illustrated with examples from gold clusters where relativistic interactions cause gold
Volume 108 Issue 3 June 1996 pp 278-278 Modern Trends In Inorganic Chemistry
Volume 128 Issue 9 September 2016 pp 1405-1415 Regular Article
Chiral ruthenium half-sandwich complexes were prepared using a chelating diamine made from proline with a phenyl, ethyl, or benzyl group, instead of hydrogen on one of the coordinating arms. Three of these complexes were obtained as single diastereoisomers and their configuration identified by X-ray crystallography. The complexes are recyclable catalysts for the reduction of ketones to chiral alcohols in water. A ruthenium hydride species is identified as the active species by NMR spectroscopy and isotopic labelling experiments.Maximum enantio-selectivity was attained when a phenyl group was directly attached to the primary amine on the diamine ligand derived from proline.