Activation of C-H bonds mediated by Mo Mo moieties in heterobimetallic Zn/O/Mo clusters

摘要

Heterobimetallic drive and cooperativity lead to a striking scenario for C-H bond activation and heteroaggregation involving Mo-III dimers. Reaction of (RO)(3)Mo Mo(OR)(3) with molar excess of ZnMe2 at -78 degrees C affords the novel mixed Zn, Mo oxo clusters [Mo-2(MeZn)(6)(mu(2)-Me)(mu(3)-CH2)(2)(OR)(7)] 1 (R = neopentyl) and 2 (R = cyclohexyl) preserving the Mo Mo triple bond, while the same reaction performed at ambient temperature gives rise to the related cluster [Mo-2(MeZn)(6)(mu(2)-CH2)(mu(3)-CH2)(2)(OR)(6)] 3. These complexes represent the first examples of heterobimetallic Mo Mo complexes with bridging methyl and methylene groups and agostic C-H -> Mo interactions, as well as penta-coordinate carbon. The complexes 1-3 were characterized by elemental analyses, multinuclear NMR and single-crystal X-ray diffraction analysis.