Notes. Open-shell molybdenum carbonyl complexes and the binding of π-acid ligands to higher-oxidation-state molybdenum sites

Abstract

Molybdenum sites which have a mixed-ligand tertiary phosphine and dithiocarbamate environment bind carbon monoxide at three oxidation levels, Mo^II and open-shell Mo^III and Mo^IV. The complex [Mo^III(CO)(S₂CNEt₂)₂(Ph₂PCH₂CH₂PPh₂)]⁺ is stable in tetrahydrofuran at 0 °C and may be prepared by low-temperature controlled-potential electrolysis. The open-shell Mo^III–CO and Mo^IV–CO complexes are new; their significance to the binding of π-acid ligands to higher-oxidation-state molybdenum sites in the nitrogenase system is briefly discussed.