Diorganotin(IV) complexes with furan-2-carbohydrazone derivatives: synthesis, characterization, crystal structure and antibacterial activity

Abstract

Four new diorganotin(IV) complexes, R₂SnL (L = L^a: R = Me 1, Ph 2; L = L^b: R = Me 3, and Ph 4), have been synthesized by reaction of hydrazone ONO donors, 5-bromo-2-hydroxybenzaldehyde furan-2-carbohydrazone (H₂L^a) and 2-hydroxynaphthaldehyde furan-2-carbohydrazone (H₂L^b) with diorganotin(IV) dichloride in the presence of a base. The compounds have been investigated by elemental analysis and IR, ¹H NMR, and ¹¹⁹Sn NMR spectroscopies. Spectroscopic studies show that the hydrazone is a tridentate dianionic ligand, coordinating via the imine nitrogen and phenolic and enolic oxygens. The structures of H₂L^b and 3 have also been confirmed by X-ray crystallography. The results show that the structure of 3 is a distorted square pyramid with imine nitrogen in apical position. The in vitro antibacterial activities of ligands and complexes have been evaluated against gram-positive (Bacillus cereus and Staphylococcus aureus) and gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. H₂L^a and H₂L^b show no activity but the diphenyltin(IV) complexes exhibit good activities towards two bacterial strains in comparison with standard bacterial drugs.

Keywords:

• Organotin(IV)
• Hydrazone
• Crystal structure
• Antibacterial activity

Acknowledgments

Support of this work by Shahid Chamran University, Ahvaz, Iran (Grant 1391) is gratefully acknowledged. DMM would like to thank generous support by CONACYT (F58692) and DGAPA-UNAM (IN227008). RRM thanks CONACYT for a postdoctoral scholarship (Agreement No. 290586-UNAM).