Density functional studies of [(alkoxy-carbonyl)methyl]cobalt tricarbonyl triphenylphosphine complexes:: an α-ester η3-coordination

Spectroscopic and structural data of 15 complexes with the general formula of RO(O)CCH2CO(CO)(3)PPh3 indicate a novel coordination mode of the alpha-ester group to the central cobalt atom, which was found to be crucial in the formation of configurational chirality of the ester carbon atom. Stereoselective self-assembly, elongated ester carbonyl bond lengths, reduced carbonyl stretching frequencies, and C-13/P-31 NMR coupling constants show an activated alpha-ester group compared to the uncoordinated ester or to that in a more distal position. Density functional calculations were carried out to describe the nature of this new bonding, termed earlier as 'autosolvation'. (C) 2002 Elsevier Science B.V. All rights reserved.