Synthesis, characterization, in vitro antioxidant and antimicrobial activities of diorganotin(IV) complexes derived from hydrazide Schiff base ligands

Abstract

We have synthesized new diorganotin(IV) complexes of the type R₂SnL (where R; methyl, ethyl, butyl and phenyl) of Schiff base ligands N'-(5-chloro-2-hydroxybenzylidene)thiophene-2-carbohydrazide (H₂L¹), N'-(4-(diethylamino)-2-hydroxybenzylidene)thiophene-2-carbohydrazide (H₂L²), N'-(3,5-dibromo-2-hydroxybenzylidene)thiophene-2-carbohydrazide (H₂L³) and N'-(2-hydroxy-5-methoxy-3-nitrobenzylidene)thiophene-2-carbohydrazide (H₂L⁴). Spectroscopic methods (FT-IR, UV–vis, ¹H, ¹³C and ¹¹⁹Sn NMR), elemental analysis, mass spectrometry, melting point and molar conductance measurements were used to elucidate the structures of compounds (1-20). The spectroscopic data indicated that the Schiff bases are tridentate (NOO) in nature and coordinated to the tin metal through enolic oxygen, azomethine nitrogen and aromatic hydroxyl oxygen donor atoms to display pentacoordinated geometry around the central tin metal. To examine the biological profile, the synthesized compounds were tested for in vitro antimicrobial activity against different bacterial and fungal strains by using serial dilution method which revealed that compounds Bu₂SnL³ (15) and Ph₂SnL3 (16) were most active antimicrobial agent. The compounds were further tested for antioxidant activity by using DPPH (1,1-diphenyl-2-picrylhydrazyl) assay. Complex Ph₂SnL³ (16) exhibited highest antioxidant potential with lowest IC₅₀ value (2.95 μM) among all the tested compounds.

Graphical Abstract

Keywords:

• Schiff base
• antimicrobial
• antioxidant
• pentacoordinated
• organotin

Acknowledgements

The author Ms. Sushila Pachwania (SRF) with Sr. No. 2061510267 acknowledges University Grant Commission, New Delhi, for financial support in the form of fellowship, Dr. A.P.J. Abdul Kalam Central Instrumentation Laboratory and Department of Chemistry, GJUS&T, Hisar for providing facilities for performing the research work.

Conflict of interest

Authors declare no conflict of interest.