Phosphorus-31, cadmium-113 and mercury-199 N.M.R. studies on dithiolate complexes of cadmium and mercury and their phosphine adducts

Abstract

Phosphorus-31, cadmium-113 and mercury-199 n.m.r. spectra have been recorded for a series of O,O-dialkyldithiophosphate (dtp) and dialkyldithiocarbamate (dtc) complexes of cadmium and mercury in dichloromethane solution. Both types of ligand are labile on the n.m.r. time scale at room temperature, although the exchange of dtc ligands can be slowed at low temperatures.

.The complexes interact with tributylphosphine and tricyclohexylphosphine (pcy), but at room temperature the phosphines are also labile. At low temperatures, however, the phosphine exchange becomes slow on the n.m.r. time scale to allow identification of the adducts except for Cd(dtc)₂ adducts with PBu₃ which are still labile at -110°C.

All the data indicate that cadmium has a lower affinity for phosphine than mercury and that dtc ligands are more strongly bound to the metals than dtp ligands.