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FTIR, 1H NMR, TGA, TEM AND BIOLOGICAL STUDIES ON THE NEW SYNTHESIZED NANO ZIRCONIUM(IV) CAPTOPRIL HYPERTENSION DRUG COMPLEX

KHULOUD A. ALIBRAHIM *

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Captopril (H2cap) is currently used to treat arterial hypertension and some types of congestive heart failure and to prevent kidney failure due to high blood pressure and diabetes. In an alkaline medium, a new zirconium(IV) complex was synthesized through the chemical reaction between H2cap drug ligand and Zr(SO4)2 • H2O hydrated salt in a ratio of 1:1 (metal:ligand). The structure interpretation of Zr(IV) complex has been confirmed using microanalytical analysis, molar conductance, infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) spectra, thermogravimetric (TGA) and differential thermogravimetric (DrTGA) analysis. Spectroscopic analysis of the synthesized Zr(IV) complex in solid state form showed that the coordination occurs through the oxygen of carboxylate COO and amido groups C=O, as well as sulphur atom of –SH group. The H2cap ligand acts as a tridentate chelate after the deprotonation of both hydrogen atoms from the ligand in an alkaline medium, with the presence of three water molecules inside the coordination sphere of the complex. These results are supported by elemental analysis as well as by molar conductance and TGA/DrTGA measurements. The experimental results revealed that the Zr(IV) complex has an approximate octahedral geometry around zirconium metal ion with formula [Zr(cap)(H2O)3] • 7 H2O. Nanoscale of the synthesized complex was studied by transmission electron microscopy (TEM). The antimicrobial efficiency of Zr(IV) complex was carried out against Escherichia coli, Bacillus subtilis and antifungal (Aspergillus niger and Aspergillus flavus).