Activation of C–H bonds mediated by MoMo moieties in heterobimetallic Zn/O/Moclusters

Abstract

Heterobimetallic drive and cooperativity lead to a striking scenario for C–H bond activation and heteroaggregation involving Mo^III dimers. Reaction of (RO)₃MoMo(OR)₃ with molar excess of ZnMe₂ at–78 °C affords the novel mixed Zn, Mo oxo clusters [Mo₂(MeZn)₆(μ₂-Me)(μ₃-CH₂)₂(OR)₇] 1 (R = neopentyl) and 2 (R = cyclohexyl) preserving the MoMo triple bond, while the same reaction performed at ambient temperature gives rise to the related cluster [Mo₂(MeZn)₆(μ₂-CH₂)(μ₃-CH₂)₂(OR)₆] 3. These complexes represent the first examples of heterobimetallic MoMo 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.