Studies of molybdenum compounds. 4. Synthesis and structure of dibenzyl(2,2′-bipyridyl)dioxomolybdenum(VI)

Article abstract of DOI:10.1021/om50003a016

Dibenzyl(2,2′-bipyridyl)dioxomolybdenum(VI), synthesized by the reaction of benzylmagnesium chloride with dioxodibromo(2,2′-bipyridyl)molybdenum(VI), crystallizes in the orthorhombic space group P2₁2₁2₁ with a = 9.961 (3) ?, b = 12.862 (2) ?, and c = 16.156 (5) ? with Z = 4. Its structure was resolved by Patterson and Fourier methods. The three-dimensional X-ray data were measured with the θ-2θ scan technique with a scintillation detector. The structure was refined by full-matrix least-squares calculations to give R(F_o) = 0.067 and R_w(F_o) = 0.104 for 1582 unique observations above 2σ. The structure of the Mo(O)₂(bpy) moiety is coplanar as in other complexes of this type. However, the Mo-N bonds are shorter, the C-Mo-C bond angle of 155.5° is wider, and the Mo-C bonds of 2.25 (2) ? are longer than in the corresponding dimethyl or dineopentyl derivatives. Although indefinitely stable at room temperature in the solid state, the complex exhibits a tendency to decompose with Mo-C bond cleavage in solution under aerobic conditions. This is attributed to the occurrence of spontaneous Mo-C bond cleavage reactions induced by thermal motions of the coordinated bpy ligand.