PREPARATION, CHARACTERISATION AND BIOLOGICAL ACTIVITIES OF SOME METAL COMPLEXES OF NEW N [4-BI(5-THION-1,3,4-OXADIAZOLE-2YL)METHANE)METYL] DIBUTYL AMINE AND THEORETICAL STUDY

Abstract

A new Mannih base N[4-bi(5-thion-1,3,4-oxadiazole-2yl)methane)metyl] dibutyl amine (L), have been prepared and characterized by (FTIR) spectroscopy. (L) have been used as a chelating ligand to prepare a number of metal complexes with Co(III), Cu(II), Pd(II), V(IV) and Pt(IV). The complexes were isolated and characterized by (FTIR), UV-Vis spectrophotometer and flame atomic absorption techniques in addition to magnetic susceptibility, and conductivity measurement. The study of the nature of the complexes formed in absolute ethanol following the mole ratio method, gave results which were agreed with those obtained from isolated solid state studies.The antibacterial activity for the ligand and their metal complexes were studied against two selected micro-organisms Bacillus subtilis and Pseudomonas aeruginosa, the antibiotic Ampicillin has been chosen to compare their activity with those of the new compounds. Theoretical treatment of the formation of complexes in the gas phase, this was done by using the HyperChem-6 program for the Molecular mechanics and semi- empirical calculations. The heat of formation (∆H˚f) and binding energy (∆Eb) at 298K for the free ligand and their metal complexes were calculated by (PM3, ZINDO/1 and AMBER) methods. Furthermore, the electrostatic potential of the free ligand was calculated to investigate the reactive sites of the molecules. PM3 was used to evaluate the vibrational spectra of the base(L) and compare the theoretically calculated wave numbers with the experimental values by using bis(5- thion-1,3,4-oxadiazole-2yl) methane as authonetic compound. The theoretically obtained frequencies agreed with those values experimentally found, in addition, the calculation helped to assign unambiguously the most diagnostic bands.