Bis-diorganotin(IV) complexes with binucleating hydrazones derived from a methylene-bis-aromatic aldehyde as linker: Synthesis, spectral and structural characterization, antibacterial activity and DNA cleavage studies

Abstract

Two bis-hydrazone, H4La and H4Lb, have been synthesized from reaction of 5,5′-methylene-bis-salicylaldehyde with benzhydrazide and furan-2-carbohydrazide, respectively. New organotin(IV) complexes, (R2Sn)2L [L = La: R = Me (1), Ph (2); L = Lb: R = Me (3), Ph (4)] have been synthesized by reaction of dihydrazone ligands with R2SnCl2 (R = Me or Ph). The synthesized compounds have been investigated by elemental analysis and IR, 1H NMR, and 119Sn NMR spectroscopy. The structures of 1 and 2 have been also confirmed by X-ray crystallography. The results show that the dihydrazone acts as a tetrabasic ligand in the enolic form and is coordinated to two SnR2 moieties via ONO donor domains by the imine nitrogen and phenolic and enolic oxygen atoms. All complexes are binuclear and the coordination number of both tin is five. The in vitro antibacterial activity of ligands and complexes has been evaluated against Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria and compared with standard drugs. The synthesized compounds also have been investigated for the chromosomal and plasmid DNA cleavage activity. The complexes significantly inhibited bacterial growth, while none of compounds showed DNA cleavage activity.