Supramolecular homobimetallic bis-diorganotin(IV) complexes of ditopic oxygen nitrogen donor ligand: synthesis, spectroscopic characterization, crystal structure and biological screening

Abstract

Six new homobimetallic bis-diorganotin(IV) complexes: [Me2Sn]2L (1), [Et2Sn]2L (2), [n-Bu2Sn]2L (3), [Ph2Sn]2L (4), [Oct2Sn]2L (5) and [n-BuClSn]2L (6) (H 4 L=N1′, N6′-bis(2-hydroxybenzylidene)adipodihydrazide) have been synthesized and structurally characterized by means of elemental analysis, mass spectroscopy, FT-IR, NMR (1H, 13C{1H}, 119Sn) and single-crystal X-ray diffraction. Spectroscopic studies indicate coordination of the ligand to the diorganotin(IV) moieties via iminolic oxygen, nitrogen and phenolic oxygen atoms generating pentacoordinated tin centers. Single-crystal X-ray analysis of (1) revealed homobimetallic nature of complex with dimethyltin moieties oriented in trans-conformation. The ligand is non-planar with each Sn atom in a distorted square pyramidal coordination geometry. Packing diagrams suggest the essential role of C–H…N and C–H…O interactions in generating supramolecular assembly. The ligand and complexes were screened for in vitro antimicrobial activity and cytotoxicity. Compound (4) exhibits highest cytotoxicity.