Reactions between Co(II) and bis(diphenylphosphino)methane in the presence of NaBH4 or NaBH3CN

Reactions between Co(II) and bis(diphenylphosphino)methane (dppm) in the presence of NaBH 4 or NaBH 3 CN are described. The main products are the Co(I) complex, CoCl(dppm) 3 , and Co(III) complexes of the type [CoHX(dppm) 2 ]Y (where X = Cl, Y = Cl or BPh 4 ; X = Y = Br; X = Y = I; X = BH 3 CN, Y = BH 3 CN, ClO 4 , or BPh 4 ). The former has been shown by X-ray crystallography to contain a Co atom tetrahedrally coordinated by a Cl and three P atoms from three monodentate dppm ligands. Possible mechanisms for the formation of Co(III) are discussed.