Multinuclear variable-temperature nuclear magnetic resonance study of rhodium carbonyl clusters containing encapsulated heteroatoms: ligand and metal polyhedral rearrangements
Abstract
Variable-temperature multinuclear n.m.r. studies (13C, 13C-{103Rh}, 13C-{31P}, and 31P) are reported for [Rh9E(CO)21]2–, [Rh10E(CO)22]3–(E = P or As), and [Rh12Sb(CO)27]3–. In all cases, complete fluxionality of both the carbonyl and metal polyhedra are observed at high temperatures, and at low temperatures it has been possible to obtain spectra for the Rh9 and Rh10 clusters, which are fully consistent with their solid-state structures, thus allowing a complete spectroscopic assignment; the Rh12 cluster is still fluxional in solution at –97 °C.