Higher Nuclearity Rhenium Halide Clusters That Contain Re–Re Multiple Bonds

The discovery that the rhenium chloride cluster Re₃Cl₉ and its chloro-anion Re₃Cl₁₂]^3- contain a triangular cluster of Re atoms and Re–Re bond orders of two was first reported in 1963. This led very quickly to the report by F. A. Cotton of the first species with a metal–metal quadruple bond, namely, the Re₂Cl₈]^2- anion. While the field of dinuclear multiple bond chemistry has undergone explosive growth in the last 40 years, that involving the chemistry of higher nuclearity clusters with metal–metal multiple bonds is much more limited. One of the relatively few exceptions is encountered with the aforementioned rhenium halides that contain the triangular Re₃]⁹⁺ core. In the present review, the synthesis, structures and reactivity of these halide clusters and those of higher nuclearity that contain Re–Re multiple bonds are surveyed. This article provides a comprehensive review of the literature covering the 40 year period 1963–2003.