REACTIONS OF ORGANOMETALLIC OXOMETAL COMPLEXES WITH B(C6F5)(3) - SYNTHESIS, STRUCTURE, BONDING AND REACTIVITY OF [MO(ETA(5)-C5H4ME)(2)-(OB(C6F5)(3))]

Organometallic oxo complexes [M(C5H4R)(2)O] reacted with the strong Le wis 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 h as been determined by X-ray crystallography. Density functional theory (DFT) calculations on [Mo(C5H5)(2)O] and [Mo(C5H5)(2)(OBF3)] have bee n 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 charg e rather than orbitally controlled. Compound 1 reacted with PhNCO to y ield [Mo(C5H4Me)(2){OC(O)NPh}{B(C6F5)(3)}]; spectroscopic evidence and DFT calculations suggest that the Lewis acid is bound to the molybden um oxygen atom.