Synthesis, characterization and antibacterial properties of some transition metal complexes of (1H-pyrrol-2-yl)-isonicotinoylhydrazone

Abstract

A new ligand, (1H-pyrrol-2-yl)isonicotinoylhydrazone (Pyr-inh) and its metal complexes have been synthesised and characterized by elemental analyses, IR, ¹H and ¹³C-NMR, UV-Vis spectra, molar conductance, and thermogravimetry-differential thermal  analysis (TG-DTA). From the results obtained, the structure of the complexes are of general formula [M(Pyr-inh)₂Cl₂].xH₂O for M = Co(II), and Zn(II) and [M(Pyr-inh)₂(H₂O)₂]Cl₂ for Cu(II). The thermal behaviour of these complexes showed the loss of lattice water in the first step followed by decomposition of the ligand in subsequent steps. The ligand and its transition metal complexes were studied for their in vitro antibacterial activity against ten pathogenic bacterial strains. The data obtained revealed that the ligand was active against Morganella morganii and Escherichia coli, the Co(II) complex active against Klebsiella oxytoca, the Cu(II) complex showed significant activity against five out of the ten bacterial strains and the Zn(II) complex was active against all the pathogenic bacterial strains investigated.

KEY WORDS: (1H-pyrrol-2-yl)isonicotinoylhydrazone, Metal complexes, Schiff base, Synthesis, Thermal analysis, Antibacterial activity

Bull. Chem. Soc. Ethiop. 2013, 27(3), 395-404.

DOI: http://dx.doi.org/10.4314/bcse.v27i3.8