Comp Chem Research Developments

July 24, 2002
 

Bonding in hexacoordinate silyl-palladium complexes

Christopher J. Cramer, Edward C. Sherer, Christopher R. Kinsinger, Bethany L. Kormos, and Jason D. Thompson, Department of Chemistry and Supercomputing Institute, University of Minnesota.

In early 2002, Chen et al. reported the synthesis of a trinuclear palladium compound with a central palladium atom assigned as possibly having an oxidation state of VI (Science 2002, 295, 308). However, analysis of high quality density functional calculations indicates that the central palladium atom adopts a much more common oxidation state of II, and what is unusual is its interaction with two Si-Si sigma bonds acting as donors (as illustrated by the highest occupied molecular orbital shown below, where the Si-Si sigma bonds between the silicon atoms are the roughly horizontal blue tubes above and below the central palladium).

This surprising malleability of Si-Si sigma bonding may prove useful in the design of future catalysts. This work is described in Angew. Chem., Int. Ed. Engl. 2002, 41, 1953 and was also the subject of an article in Chemical & Engineering News.