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ABSTRACT: Mononuclear complex of composition [ZnII(L)].2H2O (1) (H2L = 2-((Z)-(2-(2-(2-((Z)-3,5-di-tert-butyl-2-hydroxybenzylideneamino)phenoxy)ethoxy)phenylimino)methyl)-4,6-di-tert‑butylphenol) has been synthesized and characterized. In the complex 1, the ZnII at the center is coordinated by two imine nitrogen atoms, two phenolate oxygen atoms and one ether oxygen atom from the ligand, resulting in a distorted square-pyramidal ZnN2O3 coordination geometry. Complex 1 is photoluminescence active with stokes shift of 115 nm. Geometrical parameters were computed using the Density Functional Theory (DFT) method, specifically B3LYP, with the 6–311G++(d,p) basis sets. The charge distribution within the molecule was visualized through Molecular Electrostatic Potential (MEP) surface analysis. The energy levels of the Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO) were determined that revealing substantial charge transfer within the molecule. Hirshfeld surface analysis was conducted in both three-dimensional (3D) and two-dimensional (2D) perspectives to investigate the electron distribution on the molecular surface. The Electron Localization Function (ELF) Figure was utilized to investigate the degree of relative electron localization within the molecule. Moreover, a Fukui functional analysis was employed to identify potential sites for chemical attack by different substituents. The process involved in the creation of the molecular electrostatic potential (MEP), followed by the generation of a three-dimensional color-coded visualization to emphasize reactive areas. In the realm of biological investigation, four separate receptors such as 5HL1, 8BSK, 6UJM and 6UL9 were utilized for molecular docking analyses. These analyses aimed to evaluate interactions between ligands and proteins, as well as to uncover potential resemblances among drugs.

This work describes the reaction of the potentially tetradentate Schiff-base ligand N-(2-pyridylmethy)-3-methoxysalicylaldimine (HL) with UO2(O2CMe)2·2H2O and UO2(NO3)2· 6H2O in MeOH in the absence or presence of an external base, respectively. The product from these reactions is the mononuclear complex [UO2(L)2] (1). Its structure has been determined by single-crystal, X-ray crystallography. The anionic ligand adopts two different coordination modes (1.1011, 1.1010; Harris notation) in the complex. The new compound was fully characterized by solid-state (IR, Raman and Photoluminescence spectroscopies) and solution (UV-Vis and 1H NMR spectra, conductivity measurements) techniques.

In the present work, a combined experimental and theoretical study of the N-(4,6-Dimethyl-pyrimidin-2-yl)-4-[(2-hydroxy-benzylidene)amino]benzenesulfonamide ligand (H2L) and its mononuclear and magnetically diluted binuclear Cu(II) complexes has been performed using IR, TG/DTA, magnetic, EPR, and conductivity measurements. Calculated g-tensor values showed best agreement with experimental values from EPR when carried out using the MPW1PW91 functional. Coordination of H2L to a Cu(II) center, regardless of the binding site and Cu:L stoichiometry, leads to a significant decrease in the antibacterial activity compared to the free ligand as well as reference drugs in the case of Staphylococcus aureus. Structural-activity relationship suggests that ELUMO, ΔE, dipole moment, polarizability and electrophilicity index were the most significant descriptors for the correlation with the antibacterial activity., (Copyright © 2013 Elsevier B.V. All rights reserved.)