Structural evolution and bonding properties of BSi n - / 0 (n = 4-12) clusters: Size-selected anion photoelectron spectroscopy and theoretical calculations.

Size-selected anion photoelectron spectroscopy and theoretical calculations were used to investigate the structural evolution and bonding properties of BSin -/0 (n = 4-12) clusters. The results showed that the B atom in BSi4-12 -/0 prefers to occupy the high coordination sites to form more B-Si bonds. The lowest-lying isomers of BSi4-7 -/0 primarily adopt bowl-shaped based geometries, while those of BSi8-12 -/0 are mainly dominated by prismatic based geometries. For anionic clusters, BSi11 - is the critical size of the endohedral structure, whereas BSin neutrals form the B-endohedral structure at n = 9. Interestingly, both anionic and neutral BSi11 have a D 3h symmetric tricapped tetragonal antiprism structure with the B atom at the center and exhibit 3D aromaticity. The BSi11 - anion possesses σ plus π doubly delocalized bonding characters. The natural population analysis charge distributions on the B atom are related with the structural evolution of BSin - and the B-Si interactions.