Greener synthesis and biological application of organosilicon(IV) complexes derived from semicarbazone and thiosemicarbazone of 3-acetyl-2H-chromen-2-one by microwave irradiation

A new series of silicon(IV) complexes have been synthesized by adopting classical thermal- and microwave-irradiated techniques. The complexes are prepared by the reaction of dimethyldichlorosilane and triphenylchlorosilane with the sodium salts of 1-(1-(2-oxo-2H-chromen-3-yl)ethylidene)thiosemicarbazide and 1-(1-(2-oxo-2H-chromen-3-yl)ethylidene)semicabazide in 1:1 and/or 1:2 molar ratios. Characterization of the ligands as well as of the silicon complexes has been carried out on the basis of elemental analysis, melting point determinations, molecular weight determinations, infrared, 1H NMR, 13C NMR, 29Si NMR, and electronic and mass spectral studies. Spectral studies confirm ligands to be monofunctional bidentate and trigonal bipyramidal and octahedral environments around silicon ions. The newly synthesized ligands and their complexes have been screened for antimicrobial, minimum inhibitory concentration, and pesticidal activities. The results obtained from bioassays indicate that this class of compounds can be utilized for the design of new substances with pesticidal activity and promising antimicrobial activity.