A new mononuclear copper (II) complex with an O,N,O'-tridentate Schiff base ligand: Synthesis, structural, Hirshfeld surface, electrochemical and theoretical studies

The complex formation between a newly synthesized Schiff base (SBK) ligand and copper((II) was confirmed experimentally and with molecular modeling. The structural characterization of SBCuCl.Et3N was performed using FT- IR, XRD, Hirshfeld surface and electrochemical analyses. The HS analysis indicated the presence of O center dot center dot center dot H and CH center dot center dot center dot HC hydrogen bonds and weak CH center dot center dot center dot pi interactions in the crystal package. The fingerprint plots revealed the predominance of H & sdot;& sdot;& sdot;H (69.9 %) and H & sdot;& sdot;& sdot;O/O & sdot;& sdot;& sdot;H (12.8 %) interactions in the crystal structure of the complex. In the quantum chemical part, calculations carried out at DFT/6-311++g(d, p) level, the performances of three exchange functionals CAM-B3LYP, M06-2X, and CAM-B3LYPD3BJ were tested in the prediction of covalent and non-covalent bond lengths in the metallic complex unit. Subsequently, further interesting insights on SBCuCl.Et3N were obtained through several calculations including examination of the quantum theory of atoms in molecules (QTAIM), natural atomic orbitals (NAO), natural bond orbitals (NBO), density of states (DOS) and natural bond orbitals (NBO) analyses. The Reduced Electron Density Gradient (RDG) method was used to investigate and depict non-covalent interactions in two and three dimensions.