Reactions of organometallic oxometal complexes with B(C6F5)3:: synthesis, structure, bonding and reactivity of [Mo(η5-C5H4Me)2-{OB(C6F5)3}]

Organometallic oxo complexes [M(C5H4R)(2)O] reacted with the strong Lewis acid B(C6F5)(3) at their oxo functionality to yield [M(C5H4R)(2) {OB(C6F5)(3)}] (M = Mo, R = Me 1; M = W, R = H 2). The structure of 1 has been determined by X-ray crystallography. Density functional theory (DFT) calculations on [Mo(C5H5)(2)O] and [Mo(C5H5)(2)(OBF3)] have been used to model the changes in geometry to the [Mo(C5H5)(2)O] fragment on coordination by B(C6F5)(3) and indicate that this process is charge rather than orbitally controlled. Compound 1 reacted with PhNCO to yield [Mo(C5H4Me)(2){OC(O)NPh}{B(C6F5)(3)}]; spectroscopic evidence and DFT calculations suggest that the Lewis acid is bound to the molybdenum oxygen atom.