Dehydrogenation, Methyl Elimination and Insertion Reactions of the Agostic Methyl‐Bridged Complex [Mo2Cp2(μ‐κ1:η2‐CH3)(μ‐PtBu2)(μ‐CO)]

Abstract: The high unsaturation of the title complex enabled it to react with a wide variety of molecules under mild conditions, whereby the agostic methyl ligand underwent unusual or unprecedented processes. Methane elimination occurred in the reactions with PPh2H and SiPh2H2, this being followed in the latter case by Si−H bond oxidative addition to give the hydride silylene derivative [Mo2Cp2H(μ‐PtBu2)(μ‐SiPh2)(CO)]. Dehydrogenation, however, was the dominant process in the room temperature reaction with [Fe2(CO)9], to give the unsaturated methylidyne cluster [Mo2FeCp2(μ3‐CH)(μ‐PtBu2)(CO)5] (Mo−Mo=2.6770(8) Å). In contrast, PMe elimination took place in the reaction with P4, to give the unsaturated triphosphorus complex [Mo2Cp2(μ‐η3:η3‐P3)(μ‐PtBu2)] (Mo−Mo=2.6221(3) Å). Yet a most remarkable reaction occurred with BH3⋅THF, involving insertion of two BH3 units and dehydrogenation to yield [Mo2Cp2(μ‐B2H4Me)(μ‐PtBu2)(CO)], with the novel methyldiboranyl ligand acting as a 5‐electron donor due to the presence of two 3‐centre, 2‐electron B‐H‐Mo interactions, according to spectroscopic data and DFT calculations (Mo−Mo ca. 2.65 Å). [ABSTRACT FROM AUTHOR]