Multiple bonds between transition metals and ‘bare’ main group elements. A reactive manganese–tellurium–manganese framework: synthesis structure, and alkylidene addition

Abstract

A bent manganese–tellurium–manganese framework exhibiting multiple bond character has been constructed by treatment of the solvent-stabilized organomanganese complex (η⁵-C₅Me₅)Mn(CO)₂thf (1; thf = tetrahydrofuran) with aluminium telluride in the presence of aqueous hydrochloric acid; the dinuclear product (µ-Te)[(η⁵-C₅Me₅)Mn(CO)₂]₂(2) isolated in 46% yield has been shown by X-ray crystallography to contain a central ‘bare’ tellurium bridging atom which is attached to two independent (η-C₅Me₅)Mn(CO)₂ moieties via very short Te–Mn bonds [245.9(2)pm]; this compound reacts readily with diazoalkanes to give µ-alkylidene complexes of composition (µ, η²-TeCR₂)[(η⁵C₅Me₅)Mn(CO)₂]₂[(3a) R = H, (3b) R = Me].