Structure and aromaticity of , Bi5M (M=Li, Na, K) and Bi5M+ (M=Be, Mg, Ca) clusters

Abstract: The equilibrium geometries, electronic structures, harmonic vibrational frequencies, and nucleus independent chemical shifts (NICS) of , Bi5M (M=Li, Na, K), and Bi5M+ (M=Be, Mg, Ca) clusters are calculated by the density functional theory (DFT) method. Our calculation show that the ground states of , Bi5M, and Bi5M+ species are predicted to be the D 5h , C 5v , and C 5v structures, respectively. In addition, the unit preserves its structural and electronic integrity in forming the Bi5M and Bi5M+ complexes. Molecular orbital analysis and NICS show that the planar (D 5h ) anion satisfies the Hükcel rule of 4n +2 π electrons and magnetic criteria for aromaticity with six delocalized π electrons and negative NICS values. The dissected NICS suggests that the aromaticity of (D 5h ) arise primarily from the contributions of Bi–Bi σ bonds and Bi–Bi π bonds, while the aromaticity of Bi5M and Bi5M+ mainly owe to the Bi–Bi σ bonds. [Copyright &y& Elsevier]