SYNTHESIS AND CHARACTERIZATION OF METAL COMPLEXES OF SCHIFF BASE LIGANDS DERIVED FROM 4-AMINOANTIPYRINE WITH 4-AMINOBENZOIC ACID AND BENZOIN

Abstract

Two chelate-forming Schiff bases derived from 4-aminoantipyrine with 4-aminobenzoic acid and benzoin, namely (Z)-4-(4-amino-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-ylideneamino)benzoic acid (HL 1 ) and 4-((E)-4-((E)-((R)-2-hydroxy-1,2-diphenylethylidene)amino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-ylideneamino)benzoic acid (H 2 L 2 ) were prepared and complexed with copper(II), nickel(II), cobalt(II), manganese(II) and mercury(II)chlorides in ethanol. The M(HL 1 ) 2 Cl 2 and M(HL 2 ) 2 type complexes could be isolated. The ligands and theirs metal complexes were characterized using elemental analysis, infrared and electronic, 1 H and 13 C NMR spectroscopy, molar conductance and magnetic moment measurements. The measurements showed that the HL 1 ligand is coordinated in their complexes with N,N-bidendate mode, while HL 2 ionic ligand in NNO tridentate pattern through the azomethine nitrogen, amino-group and the depotonated hydroxyl group of benzoin. The stability constants of complexes were determined spectrophotometricaly. All the studies reveal a six coordinated octahedral structure of M(HL 2 ) 2 type complexes. In vitro tests for antibacterial and antifungal activities showed that most of the prepared compounds display a good activity towards S. aureus, E. coli, B. subtilis, P. aureginosa , A. niger, A. flavus, R. stolonifer and C. albicans .