Microwave-assisted synthesis and antibacterial and pesticidal activity studies of aluminum(III) and gallium(III) complexes with a bioactive Schiff base

Abstract

Abstract Biologically potent complexes of aluminum(III) and gallium(III) derived from semicarbazone of 3-acetylcoumarin have been synthesized under microwave irradiation and investigated using a combination of microanalytical analysis, melting point, ultraviolet spectra, infrared spectra, 1H nuclear magnetic resonance (NMR) spectra, and 13C NMR spectra. Aluminum and gallium isopropoxides interact with the ligand, resulting in the formation of colored products. Based on conductance and spectral evidences, a five-coordinated structure for aluminum(III) and gallium(III) complexes has been assigned for 1:1 ratio and a six-coordinated structure for 1:2 and 1:3 ratios. The ligand is coordinated to the aluminum(III) and gallium(III) via the azomethine nitrogen atom and the enolic oxygen atom. The free ligand and its metal complexes have been tested in vitro against a number of pathogenic microorganisms in order to assess their antimicrobial and pesticidal properties. Both the ligand and its complexes were found to possess appreciable bactericidal and pesticidal properties.