Rapid Access to an Oxido-Alkylidene Complex of Mo(VI)

The first well-defined Mo oxido-alkylidene complex, [(tBu3PN)2Mo­(O)­(CHSiMe3)] (4), and its borane adduct, [(tBu3PN)2Mo­(O–B­(C6F5)3)­(CHSiMe3)] (5), have been prepared through alkylation of the bis­(phosphinimide) Mo oxido-dichlorido complex [(tBu3PN)2MoOCl2] (3). The reaction between 2 equiv of tBu3PN–SiMe3 (2) and [(DME)­MoO2Cl2] (1) generates 3 through selective elimination of (Me3Si)2O. All complexes have been studied in solution by multinuclear NMR spectroscopy and in the solid state by X-ray crystallography. Preliminary ROMP catalysis results are also presented.