Structure of oxobis(phenolato)[tris(3,5-dimethyl-1-pyrazolyl)-hydroborato]molybdenum (V).

C27H32BMoN6O3, Mr = 595.34, monoclinic, P2(1)/n, a = 16.376 (6), b = 10.438 (5), c = 17.016 (8) A, beta = 107.25 (3) degrees, V = 2777.8 A3, Z = 4, Dm = 1.37, Dx = 1.43 g cm-3, Mo K alpha,lambda = 0.71073 A, mu = 5.02 cm-1, F(000) = 1228, T = 296 K, R = 0.038, wR = 0.045 for 2457 reflections. This molecule is the first structurally characterized mononuclear molybdenum complex containing a terminal aryl oxide ligand. The central molybdenum atom adopts a distorted octahedral coordination geometry with one face of the octahedron occupied by the tridentate pyrazolylborate ligand and the opposite face by the oxo and the two phenolato ligands. The structure is compared with that of the analogous benzenethiolate complex.