Integrating schiff base ligands with diorganotin(IV) metal: Crystallographic insights and biological potency against malaria and oxidative stress

Abstract

Amidst the ongoing search for potent antimalarial agents, this research focuses on synthesizing and analyzing diorganotin(IV) complexes (3–10) with Schiff base ligands (1–2) derived from 2-amino-4‑tert-butylphenol and salicylaldehyde derivatives, revealing compelling medicinal applications. Comprehensive structural characterization of these compounds was conducted using a suite of analytical techniques, including FT-IR, NMR (1H, 13C and 119Sn), SEM-EDAX, TGA and mass spectrometry. These analyses unequivocally confirmed that the ligands coordinate to the diorganotin(IV) ion via oxygen and nitrogen donor sites in an iminol configuration, indicating a pentacoordinated stereochemistry. Furthermore, to confirm the complexes structural characteristics, SC-XRD was performed on the complex 7 [Me₂SnL2] which indicated that the compound crystallizes in a monoclinic system with distorted square pyramidal stereochemistry. Biological evaluations states that the complexes have superior biological activities compared to their respective ligands with the order of activity being: Ph2SnL1–2>Bu2SnL1−2>Et2SnL1−2>Me2SnL1−2. Complexes (6, 10) showed significant antimalarial and antioxidant efficacy, with IC50 values of 0.99 ± 0.18 - 1.69 ± 0.15 µM and 2.36 ± 0.05 - 3.16 ± 0.02 µM, respectively, comparable to standard therapeutic agents. ADMET lab 2.0 evaluation confirmed their adherence to Lipinski's Rule of Five and strong pharmacokinetic properties, including oral bioavailability, permeability and clearance, similar to standard drugs.