Dehydropolymerization of Amine-Boranes using Bis(imino)pyridine Rhodium Pre-Catalysis: σ-Amine-Borane Complexes, Nanoparticles, and Low Residual-Metal BN-Polymers that can be Chemically Repurposed.

The sigma amine-borane complexes [Rh(L1)(η :η -H B⋅NRH )][OTf] (L1=2,6-bis-[1-(2,6-diisopropylphenylimino)ethyl]pyridine, R=Me, Et, Pr) are described, alongside [Rh(L1)(NMeH )][OTf]. Using R=Me as a pre-catalyst (1 mol %) the dehydropolymerization of H B ⋅ NMeH gives [H BNMeH] selectively. Added NMeH , or the direct use of [Rh(L1)(NMeH )][OTf], is required for initiation of catalysis, which is suggested to operate through the formation of a neutral hydride complex, Rh(L1)H.