Microwave-assisted synthesis, characterization, antimicrobial, and pesticidal activity of bismuth and antimony complexes with coumarin-based ligands

Abstract

Reactions of 3-acetylcoumarin with thiosemicarbazide and semicarbazide hydrochloride resulted in the formation of 3-acetylcoumarinthiosemicarbazone (C₁₂H₁₁N₃O₂S or L¹H) and 3-acetylcoumarinsemicarbazone (C₁₂H₁₁N₃O₃ or L²H), respectively. Bi(III) and Sb(III) complexes have been synthesized by mixing metal salts in 1 : 1 and 1 : 2 molar ratios with these ligands using microwave as well as conventional heating for comparison. The authenticity of these ligands and their complexes has been established with elemental analysis, melting points, molecular weights, IR, ¹H-NMR, UV, mass spectral, and X-ray powder diffraction studies. The ligands coordinated to metal as monobasic bidentate manner and tetra- and pentacoordinated geometry have been proposed around the metals. Both ligands and complexes have been screened for antimicrobial activities. The pesticidal activities of ligands and complexes against the Corcyra cephalonica have also been tested.

Keywords:

• Bismuth(III) and antimony(III) complexes
• Antimicrobial and pesticidal activity
• Thiosemicarbazone
• Semicarbazone
• Spectral studies

Acknowledgment

The authors are grateful to U.G.C., New Delhi, for financial assistance through grant no. 34(324)/SR-I.