Comprehensive Investigation of Organotin(IV) Complexes Derived From a Novel Schiff Base: Synthesis, Characterization, Antioxidant, ADME Profiling, and In Vitro Biological Evaluation

Abstract

Six organotin(IV) complexes (1–6) were synthesized, following the general formulas as R2Sn(L)Cl and R3Sn(L), have been reported. In these complexes, L represents a Schiff base prepared by the reaction of phenylhydrazine with 5‐bromo‐2‐hydroxybenzaldehyde, and R = Me, n‐Bu, Ph. Various analytical techniques were employed to characterize and determine the structure of the newly synthesized compounds. The techniques, including the elemental analysis, molar conductivity measurements, UV–visible, FT‐IR, NMR spectroscopy, and mass spectrometry. Spectroscopic analysis suggested that the ligand (4‐bromo‐2‐[(2‐phenylhydrazinylidene)meth‐yl]phenol) (HL) coordinates with the tin (Sn) metal through its phenolic oxygen (O) and azomethine nitrogen (N) atoms. Molar conductivity measurements indicated that all the synthesized compounds are nonelectrolytes. The percent CHN analysis data also corroborates the spectroscopic results. UV–Vis spectra revealed the mode of transitions of electrons due to the π–π* transitions, n–π* transitions, and transitions involving charge transfer from the ligand to the metal, which occurred in recently developed ligand and organotin (IV) complexes. The emergence of additional bands in the FT‐IR spectra of complexes (1–6), attributed to ν(Sn–O) and ν(Sn–N), which were absent in the precursor, offers further proof for the synthesis of these complexes. NMR spectral studies give information about the nature and number of all protons having the same or different chemical environment in the structure of all the compounds being reported in this study. The potential to be used as bioactive compounds in the future was assessed by performing the biological activities (antimicrobial and antioxidant) of these synthesized compounds and the DPPH free radical method for the antioxidant potential of these compounds. Based on these assessments, it can be concluded that the ligand's efficiency improves upon complexation, primarily due to the type and quantity of alkyl groups attached to the [Sn] metal atom. ADME and studies were conducted to forecast the biological effectiveness of the ligand and its metal complexes. Among these, the ligand and complexes 1 and 4 are prioritized for docking with Aspergillus flavus, Bacillus subtilis, and Escherichia coli. The complexes 1 and 4 were found biologically more effective towards different microbes. The Antioxidant activity of the test complexes follows this trend: Methyltin(IV) complexes exhibit the lowest activity, whereas butyltin(IV) and phenyl(IV) complexes exhibit higher levels of activity, with phenyltin(IV) showing the most significant activity.