ABSTRACT
The evolution of structural and electronic properties, and dynamical fluxionality of B2Gen−/0 (n = 3–12) clusters are investigated using DFT calculations combined with CALYPSO global searching algorithm. The B atoms in B2Gen−/0 incline to bond with each other and more Ge atoms. The theoretical calculations show that B2Ge3−/0 have planar 2D structures, while the geometries of B2Ge4-7−/0 are all exohedral 3D structures dominated by bipyramid-shaped or bowl-shaped based configurations and those of B2Ge8-12−/0 majorly hold prism-shaped based geometries. B2Ge10− and B2Ge10 are confirmed as the threshold sizes of transiting from B2-exohedral to B2-endohedral geometries for anions and neutrals, respectively. Natural population analysis indicates that the electron transfers from Gen skeletons to B atoms. Interestingly, the low-lying isomers of B2Ge4−, B2Ge6−, B2Ge7−/0, B2Ge8−/0, B2Ge9−, and B2Ge12− clusters exhibit dynamical fluxionality. The ΔEI, Δ2E, and ΔEI values versus number of Ge atoms suggest that B2Gen− anions are more stable than B2Gen neutrals, except that B2Ge10 has higher stability than B2Ge10−. Molecular orbitals analysis of B2Ge10 indicates that it has σ + π double delocalised bonding patterns and electronic closed-shell configuration with a HOMO–LUMO gap of 2.17 eV. The nucleus-independent chemical shift (NICS) calculations indicate that B2Ge10−/0 clusters have aromaticity.
GRAPHICAL ABSTRACT
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