A New Type of Unsaturated triangulo Transition‐Metal Cluster and Homogeneous Catalyst

The three ReRe bonds of nearly identical length in 1 indicate that the four π electrons are delocalized in the Re three-membered ring of this cluster, which contains 44 valence electrons. Complex 1 closes the gap between clusters with 48 and 46 valence electrons and those with 42. In addition, the complex has proved to be a homogeneous hydrogenation catalyst.