Crystal packing of a zinc(II)-azide complex with a N,N,S-tridentate thiosemicarbazone ligand: An experimental and computational study

Abstract

The aim of this study was to provide a crystallographic and electronic analysis of a zinc(II)-azide complex with a N,N,S-tridentate thiosemicarbazone ligand. The characterization was performed by single-crystal X-ray diffraction, elemental analysis and FT-IR spectroscopy. This compound showed a distorted square-planar structure and its crystal structure was in the triclinic space group P1¯ with Z = 2. Based on the Hirshfeld surface analysis, the van der Waals forces, N⋅⋅⋅H hydrogen bonds and C–H⋅⋅⋅π are the main intermolecular interactions that stabilize the crystal packing assembly. In addition, the Density Functional Theory (DFT) was used to predict the electronic properties. DFT calculations estimated interaction energy of −12.6 kcal mol−1 required to form the dimer structure. Nevertheless, based on a Natural Bond Orbital (NBO) analysis, two hydrogen bonds between nitrogen atoms of the azide group and the hydrogen atom of the amine one (N–H⋅⋅⋅N) are the main interactions responsible for the stabilization of the dimer structure studied. In addition, we were also able to characterize other important intermolecular interactions as the Sulfur⋅⋅⋅Sulfur and the C–H⋅⋅⋅N formed between the azide groups and the aromatic rings performed with the Quantum Theory of Atoms in Molecules (QTAIM).