Synthesis, spectroscopic characterizations, single crystal XRD, supramolecular assembly inspection via hirshfeld surface analysis, and DFT study of a hydroxy functionalized schiff base Cu(II) complex

The current work describes the synthesis, characterization, and theoretical investigation of a copper complex with a hydroxy functionalized Schiff base ligand. The complex [Cu(DHBEE)2] was characterized by UV–Visible, FT-IR, and mass spectrometry. The crystalline nature of [Cu(DHBEE)2] was examined using X-ray diffraction (XRD), revealing that the Cu2+ ion occupies a center of inversion symmetry and adopts a square planar geometry. The supramolecular assembly was stabilized by non-covalent interactions, which were further probed by Hirshfeld surface analysis along with the computation of energy of interaction between the molecular pairs and energy frameworks. Void analysis was carried out to check whether large cavities were present in the crystal or not. Density functional theory utilizing the B3LYP/LANL2DZ/6–311 G (d) level of theory indicates that the calculated bond lengths and bond angles of [Cu(DHBEE)2] support X-ray data. The O4 and O4i atoms are the sites for electrophilic attack due to the obtained results from the MEP map, Mulliken atomic charge, and Fukui function. Furthermore, HOMO-LUMO analysis verifies the enhanced chemical reactivity of the complex as compared to the ligand. The value of the energy gap for complex and ligand displays that the order of charge transfer rises as follows: [Cu(DHBEE)2] > (DHBEE).