Donor–Acceptor Complexation and Dehydrogenation Chemistry of Aminoboranes

A series of formal donor–acceptor adducts of aminoborane (H₂BNH₂) and its N-substituted analogues (H₂BNRR′) were prepared: LB-H₂BNRR′₂-BH₃ (LB = DMAP, IPr, IPrCH₂ and PCy₃; R and R′ = H, Me or <i>t</i>Bu; IPr = [(HCNDipp)₂C:] and Dipp = 2,6-<i>i</i>Pr₂C₆H₃). To potentially access complexes of molecular boron nitride, LB-BN-LA (LA = Lewis acid), preliminary dehydrogenation chemistry involving the parent aminoborane adducts LB-H₂BNH₂-BH₃ was investigated using [Rh­(COD)­Cl]₂, CuBr, and NiBr₂ as dehydrogenation catalysts. In place of isolating the intended dehydrogenated BN donor–acceptor complexes, the formation of borazine was noted as a major product. Attempts to prepare the fluoroarylborane-capped aminoborane complexes, LB-H₂BNH₂-B­(C₆F₅)₃, are also described