Halogen Bonds Involved in Copper(I) Complexes: A Study Based on the Electronic Charge Density

Abstract

This communication describes the crystal structures of CuI complexes and their topological analysis with an emphasis on the Laplacian of the electron density to investigate the characteristics of halogen bonding. To gain insight into the halogen bonds (XBs), we survey wavefunction and DFT methods. The different XBs, that is, Cl···Cl–, I···I–, Br···N3–, and I···SCN–, in the crystal packing of these compounds are categorized as a combination of a region of charge depletion and a region of charge concentration in the valence‐shell charge concentration or hole–lump interactions. The full quantum potential based lump–hole concept is more useful than the σ‐hole concept, in which the electrostatic portion of the potential is merely considered. Such a view of halogen bonding can rationalize the geometry around the XBs. The noncovalent interaction reduced density gradient (NCI‐RDG) approach was applied to the real‐space visualization and quantitative investigation of the XBs as well.