Conventional and microwave synthesis, spectral, thermal and antimicrobial studies of some transition metal complexes containing 2-amino-5-methylthiazole moiety

Abstract EN

Schiff base metal complexes of Cr (III), Co (II), Ni (II) and Cu (II) derived from 5-chlorosalicylidene-2-amino-5-methylthiazole (HL1) and 2-hydroxy-1-naphthylidene-2-amino-5-methylthiazole (HL2) have been synthesized by conventional as well as microwave methods.

These compounds have been characterized by elemental analysis, FT-IR, FAB-mass, molar conductance, electronic spectra, 1H-NMR, ESR, magnetic susceptibility, thermal, electrical conductivity and XRD analyses.

The complexes exhibit coordination number 4 or 6.

The complexes are coloured and stable in air.

Analytical data reveal that all the complexes exhibit 1 : 2 (metal : ligand) ratio.

IR data show that the ligand coordinates with the metal ions in a bidentate manner through the phenolic oxygen and azomethine nitrogen.

FAB-mass and thermal data show degradation pattern of the complexes.

The thermal behaviour of metal complexes shows that the hydrated complexes lose water molecules of hydration in the first step ; followed by decomposition of ligand molecules in the subsequent steps.

XRD patterns indicate crystalline nature for the complexes.

The Schiff bases and metal complexes show good activity against the Gram-positive bacteria ; Staphylococcus aureus and Gram-negative bacteria ; Escherichia coli and fungi Aspergillus niger and Candida albicans.

The antimicrobial results also indicate that the metal complexes are better antimicrobial agents as compared to the Schiff bases.