Document Type : Original Article
Authors
1
Ass. Prof. of Inorganic Chemistry, Chemistry Dept., Faculty of Science, Mansoura University, Egypt
2
Chemistry Department, Faculty of Science, Al-Azhar University, Cairo, Egypt
3
Chemistry Department, Faculty of Science, Mansoura University, Mansoura 35566, Egypt.
Abstract
The reaction of two thiosemicarbazides, H4DDET (2,2'-((9S,10S,11R,12R)-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarbonyl)bis(N-ethylhydrazine-1-carbothioamide) and H4DDPT (2,2'-((9S,10S,11R,12R)-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarbonyl)bis(N-phenylhydrazine-1-carbothioamide) with vanadyl sulphate monohydrate salt resulted into two novel binuclear complexes. The structures of the ligands and metal complexes were elucidated by elemental analyses, spectral (FTIR, UV-vis., mass, ESR and XRD) and magnetic susceptibility as well as molar conductivity measurements. On the basis of the data obtained, the complexes afforded the molecular formulae; [(VO)2(H2DDET)(H2O)2(SO4)].5H2O and [(VO)2(H4DDPT)(H2O)2(SO4)2].5H2O, respectively. IR data revealed that H4DDET acts as a binegative NOS tridentate coordinating one metal ion in the enol-thiol form one side via C-O, ν(C=N*) and H4DDPT as neutral N2O2S2 through O atom of C=O, N atom of N2H and S of C=S groups. The UV-vis. spectral data and magnetic moment values suggested an octahedral for both complexes. Also, ESR spectra of strongly coupled pairs showed a single broad line with non-homogeneous broadening. The data agree well with the subnormal magnetic moment values (µeff 1.00 and 1.18 B.M, respectively confirming a binuclear structure and the g value indicates an appreciable covalency which originates from the fact that thiolato sulphur binding in this complex incorporates greater covalency in the metal-ligand bonding through delocalized dπ –Pπ in plane π-bonding. Thermal gravimetric analysis (TGA) and differential thermal gravimetric analysis(DrTGA) study were carried out to examine the thermal stability and the nature of solvent molecules and the associated kinetic parameters of the degradation steps were evaluated. XRD study of [(VO)2(H2DDET)(H2O)2(SO4)].5H2O indicated that the complex crystallized in cubic C36H81AsCl4N24NiO24S4 structure with lattice constant a= 12.3438 Å, b= 12.5011 Å, c= 24.4502 Å; α= 100.095º β= 90.307 º γ= 95.425 º and P -1 space group. Molecular modelling by DFT was done to determine the active sites of thiosemicarbazide moiety that appeared at carbonyl oxygen atoms, N of NH or S of C=S groups. Additionally, parameters like geometry, Mullikan population, Mullikan charge and HOMO-LUMO gap were evaluated. The title compounds were screened for antioxidant activity such as SOD-like activity and scavenging of hydroxyl radicals. Finally, the antibacterial activity was tested and the data revealed higher inhibition power on chelation.
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