One-Step Synthesis of [HM3(CO)11]-from M3(CO)12(M = Fe, Ru, Os) via Unusual Hydride Transfer from 1,3,5-Trimethyl-1,3,5-triazacyclohexane

Reactions of M3(CO)12 and (MeNCH2)3 (1,3,5-trimethyl-1,3,5-triazacyclohexane) in refluxing n-hexane generate the anionic hydrido clusters [(μ-H)M3(CO)11][MeN(MeNCH2)2CH] (1 and 2 for M = Fe and Ru, respectively) in good yields, while heating Os3(CO)12 and (MeNCH2)3 results in fragmentation of the triazacyclohexane ligand to yield the amidino complex (μ-H)Os3(CO)9(μ3,η2-CH(NMe)2) (4). The Os3 analogue [(μ-H)Os3(CO)11][MeN(MeNCH2)2CH] (3) is produced by treatment of Os3(CO)12 with (MeNCH2)3 in the presence of Me3NO at room temperature or by treatment of Os3(CO)11(NCMe) with (MeNCH2)3 at room temperature. A pathway involving β-hydride abstraction from a CH2 unit of the bound (MeNCH2)3 ligand is proposed. The molecular structures of 2 and 4 are determined by an X-ray diffraction study.