Generation of aminoborane monomers RR′NBH2 from amine–boronium cations [RR′NH–BH2L]+: metal catalyst-free formation of polyaminoboranes at ambient temperature

Abstract

Protonation of MeRNH·BH₃ (R = Me or H) with HX (X = B(C₆F₅)₄, OTf, or Cl), followed by immediate, spontaneous H₂ elimination, yielded the amine–boronium cation salt [MeRNH·BH₂(OEt₂)][B(C₆F₅)₄] and related polar covalent analogs, MeRNH·BH₂X (X = OTf or Cl). These species can be deprotonated to conveniently generate reactive aminoborane monomers MeRNBH₂ which oligomerize or polymerize; in the case of MeNH₂·BH₃, the two step process gave poly(N-methylaminoborane), [MeNH–BH₂]_n.