Mechanistic insights into H3B·NMeH2 dehydrogenation by Co-based complexes: a DFT perspective

Abstract

For chemical hydrogen storage materials, amine borane adducts have attracted significant attention as they feature a high theoretical hydrogen capacity and are potential precursors for the synthesis of various inorganic materials. Density functional theory calculations were used to study the dehydrogenation mechanism of H₃B·NMeH₂ catalyzed by cobalt complexes, together with investigation into polyaminoborane formation. The computational results showed that Co-based complexes are efficient catalysts for amine borane dehydropolymerization with the aid of NMeH₂, which can be operated at low loadings, selectively giving (H₂BNMeH)_n polymer in scale. The role of NMeH₂ is highlighted in promoting the hydride transfer processes and bringing the precatalyst into the cycle of H₃B·NMeH₂ dehydrogenation. Polyaminoborane formation was also investigated, suggesting a nucleophilic head-to-tail polymerization mechanism.