Synthesis of Molybdenum(VI) Tritylimido Alkylidene Complexes

Mo(NCPh3)(CHCMe2Ph)(OTf)2(DME) (1) can be prepared in 46% yield through addition of 3 equiv of triflic acid to Mo(NCPh3)2(CH2CMe2Ph)2 in the presence of dimethoxyethane. Other tritylimido complexes that were prepared include Mo(NCPh3)(CHCMe2Ph)[OC(CF3)3]2 (2), Mo(NCPh3)(CHCMe2Ph)(OSiPh3)2 (3), Mo(NCPh3)(CHCMe2Ph)(η5-Me2Pyr)(η1-Me2Pyr) (4; Me2Pyr = 2,5-dimethylpyrrolide), Mo(NCPh3)(CH2CH2)(OTf)2(DME) (5), Mo(NCPh3)(OSiPh3)2Cl2(THF) (6), and [(Ph3SiO)2(NCPh3)Mo]2(μ-O)(μ-Cl)2 (7). Single crystal X-ray diffraction studies were carried out for 2, 4, 5, 6, and 7. These results demonstrate that tritylimido is a robust, sterically demanding alkylimido ligand that complements less sterically demanding t-butylimido and 1-adamantylimido ligands.