Synthesis and crystal structure of hydrido(tetrahydroborato)tetrakis(trimethylphosphine)molybdenum(II)

Abstract

The interaction of trichlorotris(tetrahydrofuran)molybdenum(III), MoCl₃(C₄H₈O)₃, with trimethylphosphine in ether or tetrahydrofuran gives trichlorotris(trimethylphosphine)molybdenum(III). This has been shown to react with sodium borohydride to yield MoH(BH₄)(PMe₃)₄, whose structure has been determined by X-ray crystallography. The compound crystallizes in the orthorhombic space group Cmcm with a= 12.572(5), b= 12.405(5), c= 14.433(6)Å, and Z= 4 for D_c= 1.23 g cm^–3. The final R factor was 0.048 based on 1 078 independent observed reflections. In the crystal the molecules lies at the intersection of two mirror planes, with the hydride, the molybdenum atom, and the boron atom of the bidentate BH₄ group lying precisely on the intersection. Hydrogen-1 and ³¹P n.m.r. spectra for the complex are also briefly reported.