Computational evaluation of the adsorption and dissociation of aminoboranes on B28-xNx (x=0-5) nanocages

In this study, a theoretical investigation based on Density Functional Theory (DFT) was conducted to evaluate the adsorption and dehydrogenation behavior of ammonia borane (H₃NBH₃, AB), aminoborane (H₂NBH₂, AM), and iminoborane (HNBH, IM) on boron–nitrogen 0D nanostructures (B 28-x N x , x = 0–5). Benchmark calculations identified ωB97XD/6-311G(d,p) as the most suitable level of theory for describing the structural properties and dipole moments of the studied molecules, with the closest agreement to experimental reference data. The calculated adsorption energies, together with the electronic characterization of the optimized complexes, indicate that B₂₄N₄ and B₂₆N₂ promote the strongest interactions with AB and AM. Notably, the AB–B₂₄N₄ system under global negative charge conditions (Q = −1|e|) undergoes spontaneous partial dehydrogenation, yielding a dissociated state in which one proton-like and one hydride-like hydrogen atom become chemisorbed on the fullerene surface. This process is accompanied by an adsorption energy of −3.47 eV, spin-dependent HOMO–LUMO gaps of 5.11 eV (↑) and 5.96 eV (↓), and a work function of 2.77 eV indicating a pronounced electronic response under global negative charge conditions. The associated redistribution of charge density and bonding pattern is consistent with the formation of strong adsorption sites, whereas the remaining aminoborane fragment is only weakly retained after dehydrogenation. H₂NBH₂ also exhibits dissociative interaction on B₂₄N₄ and B₂₆N₂ through hydride transfer and stable B–B bond formation. By contrast, HNBH remains weakly physisorbed on B₂₈ and B₂₇N, while chemisorption becomes more favorable with increasing nitrogen content in the fullerene. These findings position B₂₄N₄ and B₂₆N₂ as the most reactive nanocages in the series and support the potential of B–N fullerene-like nanostructures as metal-free platforms for aminoborane activation and dehydrogenation.