LAUSR

Abstract In this article, the geometrical and electronic structures of a series of borepin and beryllepin transition-metal sandwich complexes M(C6H6R)2 (R = BH, Be; M = Cr, Mo, W) have been systematically investigated at the B3LYP and BP86 levels of theory. Comparing to Cr(C6H6)2, the optimized structures possess the relatively larger binding energies, similar HOMO-LUMO and fundamental gaps. The topology parameters and energy decomposition analyses show the M-C6H6R bonding interactions are mostly covalent bonds. The detailed molecular orbital and Adaptive Natural Density Partitioning analyses indicate that the spd-π interaction plays an important role in stabilizing M(C6H6R)2. Nucleus independent chemical shift (NICS) analysis indicates the aromaticity of the C6H7B/C6H6Be ligands is strengthened by the metal atoms in the sandwich complexes M(C6H6R)2. Based on the negative free energy changes of the reactions of the C6H7B/C6H6Be ligands with M(C6H6)2, the concerned borepin and beryllepin sandwich complexes probably are synthesized in gas phases.