Synthesis and theoretical calculation of trinuclear copper Schiff-base complex: Intermolecular interactions induced racemic pair

Abstract

Supramolecular materials resulting from crystalline structure programmed by heterochiral assemblies are currently attracting increasing attention. Herein, we reported a self-assembly based on racemic trinuclear-copper Schiff base complex [Cu3Cl-salpn2Cl2(H2O)] (1). Structural analysis shows that the vanish of the molecular symmetry is closely related to the asymmetric intermolecular interactions on both sides of the wings of butterfly shaped compound, that is, strong π···π interactions on one side and weak CH···π interactions on the other side. To gain insight into the observation, the gas-phase structural optimization and single-point energy calculation for 1 were performed at the DFT level, which result revealed that in the absence of intermolecular interactions the optimized structure exhibited an ideal symmetric structure, suggesting the asymmetric intermolecular interactions was the main factor for the formation of the heterochiral enantiomers. In addition, the magnetic behaviors of the reported trinuclear-copper complex were also investigated.