Copper(II) Monomer Bearing Phenolate-Based Ligand: Theoretical and Experimental Visions

Using protonated forms of tridentate phenol amine ligand 2-((benzyl(pyridine-2-ylmethyl)amino)methyl)phenol (HL) mononuclear copper(II) complex was synthesized. This ligand yielded mononuclear complex of composition [Cu(HL)Cl2] (1) which has been characterized by X-ray crystallography, UV–vis, and EPR measurements. Complex 1 shows axial spectra typical of d9 (dx2-y2 as ground state) configuration. Using DFT/B3LYP/LANL2DZ and 6-311++G(d,p) level of theory, structural optimization, electronic and vibrational characteristics of the ligand and complex were examined. The experimental and theoretical parameters are quite well aligned. The assignments of the vibrational frequencies were performed by potential energy distribution analysis by using VEDA program. Molecular electrostatic potential and frontier molecular orbitals analysis have been carried out to understand the molecule reactivity. A TD-DFT computation is also started to replicate the UV–vis absorption spectrum and to determine various essential electronic parameters such as the HOMO–LUMO gap energy and electronic transitions.</p

Dinuclear Phenoxo-Bridged Nickel(II) and Copper(II) Complexes of Phenolate-Based Tripodal Ligand: Theoretical and Experimental Insights

Three dinuclear complexes of composition [NiII2(L)2][ClO4]2 and [CuII2(L)2(OClO3)2].3H2O have been synthesized using a new tripodal ligand [(2-pyridyl)methyl](2-benzyl)-aminomethyl}-phenol (HL)], in its deprotonated form, providing a N2O donor set. Crystallographic analyses reveal that [CuII2(L)2(OClO3)2].3H2O has a diphenoxo-bridged structure. In [CuII2(L)2(OClO3)2].3H2O, each metal center is MIIN2O3-coordinated with a square-pyramidal environment for each copper(II) center. In this work, the molecular structure, harmonic vibrational frequencies and UV-Vis of [NiII2(L)2]2+ and [CuII2(L)2]2+ has been explored. With the help of density functional theory (DFT)/B3LYP techniques and LANL2DZ as a basis set, the ground-state molecule shape and vibrational frequencies were computed. The basic vibrations were allocated using the VEDA program to compute the potential energy distribution (PED) of the vibrational modes. The band gap energies of the title complexes ([NiII2(L)2]2+ and [CuII2(L)2]2+) are 3.21 eV and 1.59 eV, respectively, according to HOMO-LUMO energies. The maximal absorption wavelength and band gap energy of the title complexes were calculated theoretically using the UV absorption spectra. MEP analysis identifies electrophilic and nucleophilic sites. Hirshfeld surface analysis was used to characterize the 3D intermolecular interactions in ([NiII2(L)2]2+ and [CuII2(L)2]2+) of the crystal surface, whereas fingerprint plots were used to explain the 2D interactions. The biological activity of the complexes was investigated using molecular docking.</p