SYNTHESIS, CHARACTERIZATION AND ANTIMICROBIAL SCREENING OF SOME MIXED LIGAND COMPLEXES OF DIOXOURANIUM

Abstract

Abstract Complexes of Nicotinic hydrazide (NH) and isonicotinic acid hydrazide (INH) with uranylnitrate and uranylacetate were prepared; [UO2(NH)2(NO3)2]nH2O 1, [UO2(INH)2(NO3)2]nH2O 2, [UO2(NH)2(CH3COO)2]nH2O 3 and [UO2(INH)2(CH3COO)2] nH2O 4 and characterized. They recorded melting points ranging between 154 – 189 oC and shows non electrolytic character in solution indicating the ligands and complexes are neutral compounds. IR and uranium elemental analysis revealed mixed ligand complexes where the hydrazide ligands show bidentate coordination through the carbonyl oxygen and the hydrazinic nitrogen leading to the formation of a 5-membered chelate with uranium(VI) ion. All complexes adopt octahedral geometry with two nitrate and acetate ions respectively occupying the fifth and sixth coordination sites of the complexes via unidentate mode of coordination. Electronic spectral studies display spectra bands between 320 – 350 nm and 400 – 500 nm in the spectra of the complexes due to intraligand and charge transfer transitions respectively. Antimicrobial studies revealed that [UO2(NH)2(NO3)2] and [UO2(INH)2(NO3)2] exhibited a fair inhibition of the growth of S. aureus. All other compounds did not display antimicrobial action against all the organisms tested. The complex compounds are stable recommending the ligands can find application in uranium spectroanalysis and in pollution remediation.