Synthesis, spectral characterization, structural studies, molecular docking and antimicrobial evaluation of new dioxidouranium(vi) complexes incorporating tetradentate N2O2 Schiff base ligands

Abstract

Two new uranyl(VI) Schiff base complexes [UO₂(L¹)(DMSO)] (1), where L¹ = N,N′-di(5-bromosalicylidene)-1,2-cyclohexyldiaminate ligand and [UO₂(L²)(MeOH)] (2), where L² = N,N′-di(5-bromosalicylidene)-o-phenylenediaminate ligand, were synthesized and characterized by elemental analysis, ¹H NMR, FTIR, UV-vis, fluorescence spectroscopy and molar conductivity measurements. The structure of the H₂L¹ free ligand and both complexes (1) and (2) were also determined by single crystal X-ray diffraction. According to the results obtained, the title complexes have a distorted pentagonal bipyramidal geometry where positions around the U(VI) centre are occupied by the ONNO donors of the deprotonated dibasic Schiff base ligands (L¹ for 1 and L² for (2)), two oxido groups and the oxygen of coordinated solvent. The antimicrobial activity of ligands and complexes was also screened against Gram positive bacteria Staphylococcus aureus PTCC 1112, Micrococcus luteus PTCC 1110, Bacillus cereus PTCC 1015, Enterococcus faecalis; Gram negative bacteria Pseudomonas aeruginosa PTCC 1214, Escherichia coli PTCC1330, Pseudomonas sp., Klebsiella pneumoniae; and fungus strain (Candida albicans). The molecular docking of GlcN-6-P synthase with the synthesized compounds was also performed. According to the results, complex 2 displayed minimum binding energy and can be considered as a good antimicrobial agent.