Copper(i) complexes of functionalized sulfur-containing ligands: structural and theoretical insights into chalcogen bonding

Abstract

Herein, we report on the synthesis of new copper(I) complexes with sulfur-containing ligands. Structural analysis unequivocally shows that S⋯S chalcogen bonding (ChB), CH⋯S hydrogen bonding, and CH⋯π contacts are the major intermolecular interactions. The influence of sulfur interactions on the supramolecular assemblies has been investigated by geometrical analysis and theoretical calculations. Topological analysis has also been conducted, with respect to the electron density, Laplacian of electron density, and electron localization function (ELF), in order to inspect the physical characteristics of the ChB interactions. The non-covalent sulfur interactions in crystalline structures have been evaluated by wave function and DFT methods to acquire insight into the ChB interactions. So, the S⋯X (X = S, O, N, Cl) interactions in the crystal packing can be categorized as lump–hole interactions; a region of charge depletion (hole) of sulfur interacts with a region of charge concentration (lump) of another involved atom in the valence shell charge concentration (VSCC) which forms a chalcogen bond. The presence of electron deficiency on the sulfur atoms leading to the S⋯X chalcogen bonds has also been visualized on electrostatic potential maps. Indeed, the lump–hole concept has shown that the existence of the hole in the VSCC of the sulfur atom is responsible for the generation and geometry of chalcogen bonded complexes.