Synthesis, characterization, single crystal structure, biological evaluation of ONO donor hydrazones and their diorganotin(IV) complexes

Abstract

We have synthesized a series of four ligands (H2L1 - H2L4) and their sixteen diorganotin(IV) complexes R''2SnL, [R'' = Me, Et, Bu, Ph]. The ligands were derived by condensation of 2-hydroxy-3-methylbenzohydrazide with different salicylaldehyde derivatives. The synthesized compounds were well characterized by various spectroscopic and physicochemical techniques like FT-IR, (1H, 13C, 119Sn) NMR, UV-Vis, SEM-EDAX, TGA, XRD, HRMS, molar conductance measurements and elemental analysis. The spectroscopic data suggested the tridentate nature (ONO) of hydrazones forming a pentacoordinated environment around the tin metal. Further, the X-ray crystallographic study of compound [Me2SnL4] (17) confirmed the anticipated results of tridentate (ONO) nature of ligands forming distorted trigonal bipyramidal geometry with the tin metal atom. The synthesized compounds were assessed for their in vitro antioxidant activity and compound [Ph2SnL1] (8) exhibited the best activity with IC50 value of 2.92 µM. In vitro antimicrobial potential of the synthesized compounds was evaluated against different microbial strains viz. S. aureus, B. subtilis, p. aeruginosa, E. coli, C. albicans, A. niger. The antimicrobial data inferred that the complexes exhibited better efficacy than their parent ligands and compound [Et2SnL4] (16) exhibited the highest activity having same MIC value of 0.0053 µmol/mL against S. aureus and A. niger. Furthermore, in silico ADME study of the compounds was also carried out and observation revealed that the compounds can be used as an orally active drugs.