Binuclear oxovanadium(IV), cerium(III) and dioxouranium(VI) nano complexes of a bis(bidentate) ligand: Synthesis, spectroscopic, thermal, DFT calculations and biological studies

A new series of binuclear oxovanadium(IV), cerium(III) and dioxouranium(VI) complexes of a bis(bidentate) ligand (4,6-diacetylresorcinol; H2L) have been synthesized. The metal complexes were characterized by using different techniques such as elemental and thermal analyses, IR, H-1 NMR, electronic, ESR, mass spectra and powder XRD, TEM and magnetic susceptibility and conductivity measurements. The ligand acts as a bis(monobasic bidentate) or bis(neutral bidentate) chelating agent forming binuclear complexes, formulated as: [(VO)(2)(L)(2)], [(VO)(2)(H2L)(SO4)(2)(H2O)(2)], ICe2(L)(NO3)(3)(H2O)(5)(EtOH)(2)]NO3, [Ce-2(L)(NO3)(4)(H2O)(3)(EtOH)(3)], [(UO2](2)(L)(OAc)(2)(MeOH)(4)]center dot nH(2)O; n = 2 or zero. Kinetic parameters (Delta E, A, Delta H, Delta S and Delta G) of the thermal decomposition stages have been calculated by Coats-Redfern equations. The geometry of the ligand and its oxovanadium(IV) complexes has been optimized using density functional theory (DFT). Total energy, energy of HOMO and LUMO, dipole moment and structure activity relationship were performed and confirmed practical antitumor results. The antimicrobial activity of the ligand and its metal complexes was investigated against the microorganisms S. aureus, B. subtilis, S. typhimurium, E. coli, C. albicans and A. fumigatus. The antitumor activity of the ligand and its oxovanadium(IV) complexes was investigated against human Hepatocelluar carcinoma cell lines. The ligand showed low antimicrobial and antitumor activities, which were improved upon complexation. (C) 2019 Elsevier B.V. All rights reserved.