Synthesis, characterization, and biological evaluation of organotin(IV) complexes derived from Schiff bases of 3-methoxybenzohydrazide

Abstract

New diorganotin(IV) complexes (R₂SnL, where R is Me, Et, Bu, and Ph) of Schiff base ligands N'-(2-hydroxybenzylidene)-3-methoxybenzohydrazide (H₂L¹), N'-(5-chloro-2-hydroxybenzylidene)-3-methoxybenzohydrazide (H₂L²), N'-(2-hydroxy-5-nitrobenzylidene)-3-methoxybenzohydrazide (H₂L³), and N'-(4-(diethylamino)-2-hydroxybenzylidene)-3-methoxybenzohydrazidefrom (H₂L⁴) derived from 3-methoxybenzohydrazide with salicylaldehyde and its derivatives were synthesized. The ligands and their metal complexes were structurally characterized by spectroscopic techniques (FT-IR, ¹H, ¹³C, and ¹¹⁹Sn NMR), elemental analysis, mass spectrometry, melting point, and molar conductance studies. The spectral data showed that ligands are coordinated to the tin atom in a tridentate manner with N and O donor sites of the azomethine-N, enolic-O, and aromatic hydroxyl-O to form a penta-coordinated geometry around central tin atom. The molar conductance data revealed that all compounds are non-electrolytes. In vitro antimicrobial activities of compounds were determined against various pathogens with reference to standard antibiotics which showed that compounds (12) (Ph₂SnL²) and (16) (Ph₂SnL³) are the most potent antimicrobial agents. Furthermore, the compounds were evaluated for antioxidant activity by using DPPH assay. The results obtained emphasized that the phenyl derivatives of complexes have enhanced antimicrobial and antioxidant activities as compared to other complexes. To check the drug-likeness, in silico studies of the synthesized compounds were carried out which described that all the compounds except (12) (Ph₂SnL²), (19) (Bu₂SnL⁴), and (20) (Ph₂SnL⁴) can be used as orally active drugs.

Graphical Abstract

Keywords:

• Schiff base
• antimicrobial
• antioxidant
• salicylaldehyde
• organotin

Acknowledgments

We are thankful to Dr. A.P.J. Abdul Kalam Central Instrumentation Laboratory and Department of Chemistry, GJUS&T, Hisar for providing assistance in performing the research work.

Disclosure statement

Authors declare no conflict of interest.

Additional information

Funding

The author Ms. Sushila Pachwania (SRF) with Sr. No. 2061510267, Ms. Bharti Taxak (file no. 09/752(0114)/2020-EMR-I), Mr. Ankit Boora (file no. 09/752(0119)/2020-EMR-I) is grateful to University Grants Commission, New Delhi and Abdul Kalam Central Instrumentation Laboratory and Department of Chemistry, GJUS&T, Hisar for financial support in the form of fellowship.