Studies of gold cluster compounds using high-resolution 31P solid-state nuclear magnetic resonance spectroscopy

High-resolution 31P n.m.r. spectra of a series of crystalline gold phosphine cluster compounds have been obtained using magic angle sample spinning. The spectra are interpreted on the basis of the known crystal structures, and are compared with corresponding spectra of the compounds in solution. With one exception, the clusters appear to be stereochemically rigid in the crystals at room temperature, although most are fluxional in solution, some even at low temperatures. In many cases separate resonances can be resolved in the solid-state spectra from the distinct phosphine environments of the cluster framework. A combination of solid-state and solution n.m.r. spectroscopy is likely to be extremely valuable in the characterisation of both the structure and dynamics of phosphine-containing cluster compounds.