Cluster Complexes

The best definition of a cluster compound is one having a triangular or bigger closed polyhedron of metal atoms. Because of their inherent importance, compounds having electrons at positions 66 (chain compounds), 68, 70, and 72 (cubane-like or cage compounds) are not considered clusters but are still covered in this study. The chemistry of the transition metals is expanded by the virtually infinite diversity provided by metal cluster complexes. The study of this novel chemistry will be considerably aided by transition metal NMR. This boundary between complexes of single metal atoms and of tiny metal particles provides a potentially vast spectrum of new chemistry. Rhodium produces a number of distinct clusters generated from Rh4(CO)12 and Rh6(CO)16 that have served as the foundation for the majority of the current chemistry of rhodium clusters. Heaton and coworkers have by far made the most contribution to the study of tiny rhodium-containing clusters by 103Rh NMR. Their more than 30 publications providing 103Rh data have been published in the following journals: 26, 27, 136, 142-171. (see Tables A4a and A4b).