Square Planar Ru(iPr2PCH2CH2NH)2 and its Role in Fast and Selective Catalytic Amine-Borane Dehydropolymerization to Form High Molecular Weight Polyaminoboranes.

Addition of tBuOK to orange RuCl 2( iPr 2PCH 2CH 2NH 2) 2 forms the pink, square planar, Ru(II) complex Ru( iPr 2PCH 2CH 2NH) 2. This is an active catalyst (ToF 250 s -1) for the dehydropolymerization of H 3B·NMeH 2 to give high molecular weight polyaminoborane, [H 2BNMeH] n (M n = 138 700 g mol -1) at low loadings (0.03 mol%). An induction period observed is due to the initial formation of a hydroxy-hydride species, Ru( iPr 2PCH 2CH 2NH 2) 2(OH)(H), prior to fast turnover.