Dehydrocoupling Reactions of Secondary and Primary Amine–Borane Adducts Catalyzed by Half-sandwich Carbonyl Complexes, [CpMn(CO)3], [(η6-C6H6)Cr(CO)3], and [CpV(CO)4]

Dehydrocoupling reactions of amine–borane adducts catalyzed by half-sandwich carbonyl complexes are described. Secondary amine–borane adducts released H2 with catalytic action of [CpMn(CO)3] (Cp: η5-C5H5), [(η6-C6H6)Cr(CO)3], and [CpV(CO)4] under photoirradiation to produce dimeric or monomeric aminoboranes. These results were parallel to the [M(CO)6]-catalyzed system (M = Cr, Mo, and W); however, the reactions were considerably slower. Dehydrocoupling of BH3·NH2Me afforded an aminoborane polymer, [BH2NHMe]n.