SYNTHESISAND ANTIMICROBIAL STUDIES OF SCHIFF BASE DERIVED FROM2-THENOYLTRIFLUOROACETONE AND 4-AMINOANTIPYRINEAND ITSCo(II), Fe(III), Ni(II) AND Cu(II) COMPLEXES

Abstract

A new ligand, 3-[2-(1, 5-dimethyl-3-oxo-2-phenyl-2, 3-dihydro-1H-pyrazol-4-yl) hydrazinylidene]-2-thenoyltrifluoroacetone (HPDP) was prepared by diazotization of 4-aminoantipyrine and coupling of the obtained diazonium salt with 2-thenoyltrifluoroacetone. It’s Co(II), Fe(III), Cu(II), Ni(II) complexes were synthesized by refluxing the ligand(HPDP) with the metal chlorides in absolute ethanol for 6 hrs. Obtained compounds were characterized by means of melting point, conductivity, elemental analysis UV-Visible, FT-IR, 1H and 1 3C NMR.The molar conductivity values indicated that,[Fe(PDP)(H2O)Cl2], [Co(PDP)Cl2(OH2)], [Cu(HPDP)Cl2], [Ni(PDP)Cl2(OH2)] complexes were electrolytes when compared with CuSO4 and KCl salts respectively. The chloride analysis determination revealed the presence of chloride ions inside the coordination sphere of all the complexes. The Uv-Vis, IR, 1H and 13CNMR data of the complexes suggest square-planar geometry around Co (II), Cu (II), Ni (II) and octahedral geometry around Fe (III) ions. The ligand is tridentate and the complexes crystalized as M (HPDP). The ligand coordinated through the carbonyl oxygens and nitrogen atom of the azomethine –C=N group. The antimicrobial screening of the ligand and complexes with B.subtilis, E.coli, and P.mirabilis,S. aureus, S. intermediusS. typhi and S. pneumoniae showed more activities for the complexes than the ligand in comparison with standard drugs (Ampicillin and Ciprofloxacin), this implies that the synthesized compounds have potency for possible use as antbacterial agents against resistant strains.