Oxidative P-P Bond Addition to Cobalt(-I): Formation of a Low-Spin Cobalt(III) Phosphanido Complex

摘要

The first homoleptic cobalt phosphanido complex [K(thf)(4)][Co{1,2-(PtBu2)(2)C2B10H12}(2)] (1) was prepared by an unprecedented oxidative P-P bond addition of an ortho-carborane-substituted 1,2-diphosphetane to cobalt(-I) in [K(thf)(0.2)][Co((4)-cod)(2))] (cod=1,5-cycloctadiene). Compound 1 is a rare distorted tetrahedral 3d(6) complex with a low-spin ground state configuration. Magnetic measurements revealed that the complex is diamagnetic between 2 to 270K in the solid state and at 298K in [D-8]THF solution. Based on DFT calculations, the unusual singlet ground state is caused by the strong sigma-donor and moderate -donor properties of the bis(phosphanido) ligand.