Synthesis, characterization, and microbiocidal activity of α-methyl-(2-thiophenomethylene) aryloxyacetic acid hydrazides and their metal complexes

Abstract

Complexes of α-methyl-(2-thiophenomethylene) aryloxyacetic acid hydrazides with Cu(II) and Zn(II) metal salts were synthesized and characterized by elemental analysis, molecular weight determination, molar conductance, and magnetic moment and spectroscopic techniques. In these complexes, the ligands form a conjugate O-N-S tridenate system, thus coordinating with metal through oxygen of the carbonyl group, nitrogen of azomethine, and sulphur of thiophenemoiety. Octahedral geometry is proposed for all the complexes. Antifungal activity of the ligands and their Cu(II) and Zn(II) complexes was determined against plant pathogenic fungi viz. Alternaria alternata, Rhizoctonia solani, Colletotrichum capsicum, and Glomeralla cingulata at 28°C. Antibacterial activity of ligands and their metal complexes was determined on gram positive Bacillus subtilis and gram negative Escherichia coli bacteria at 37°C by the serial dilution method. In some cases an increase in biocidal activity of the ligands on coordination with metal ions was observed in terms of minimum inhibitory concentration (MIC) values.