A tetranuclear carbonyl fluoro rhenium(I) cluster, [Re(CO)3F]4,4H2O

Abstract

The title compound has been prepared from Re(CO)5Br by a bromide-abstraction reaction with silver fluoride. It completes the series of known halide clusters of the type [Re(CO)3X]4 (where X = halide). The crystals are tetragonal, space group 14, with a 11.716(5), c 8.988(3) �, and Z 2. The structure was refined by full-matrix least-squares to an R value of 0.027 for 1380 observed reflections. The molecules are cubane-type clusters of Re(CO)3 groups at one set of corners interpenetrated with fluorine atoms at the other set. The clusters exhibit the molecular symmetry 43m. Each of the fluorine atoms is involved in μ3 type bridging with the rhenium atoms at an average bonding distance of 2.200(5) �. The clusters are held together by hydrogen bonding of fluoride to water molecules.