Cluster rhenium(III) complexes with adamantanecarboxylic acids: Synthesis and properties

Abstract
Versatile procedures for the synthesis of possible structural types of dirhenium(III) halocarboxylates with adamantanecarboxylic acids were developed. A comprehensive study of the synthesis and interconversions of isomeric dirhenium(III) trans-and cis-tetrahalodi-μ-carboxylates led us to a discovery of a versatile route of prepation of trans derivatives in virtually stoichiometric yields in both the solid and liquid phases. It was found that successive replacement of halide ligands in the nearest environment of the binuclear Re 2 6+ ion by carboxylate ligands is accompanied by gradual hypsochromic shifting of the longest-wavelength absorption band and by a monotonic decline in its intensity, which allows this band to be assigned to the δ-δ* electronic transition.