Four triorganotin(IV) esters based on 3,5-bifluorobenzenetelluronic acid: Syntheses, structures, in vitro cytostatic activity and BSA-binding assessment

Abstract

Four novel 3,5-bifluorobenzenetelluronic triorganotin(IV) esters, namely (3,5-F2C6H3TeOH)2(μ-O)2(OSnR3)4 (R = Me: 1, R = Ph: 2) and (3,5-F2C6H3TeOH)(OSnR3)4 (R = Me: 3, R = Ph: 4) have been synthesized and characterized by the reaction of deprotonated 3,5-bifluorobenzenetelluronic acid ligand and corresponding R3SnCl (R = Me, Ph). All the complexes have been characterized by means of elemental analysis, FT-IR, NMR (1H, 13C, 119Sn) spectroscopy, and X-ray crystallography. Structural analyses of these complexes reveal that complexes 1 and 2 exhibit centrosymmetric dimeric structure with an almost planar four-membered Te2(μ2-O)2 core in the center, while 3 and 4 form monomeric structure with a single Te center. The Te atoms adopt octahedral geometry in all the complexes. Complexes 1–4 could form 2D or 3D supramolecular structures through intermolecular C-H···F or C-H···O interactions. Preliminary in vitro cytostatic studies show that complexes 1–4 exhibit effective cytostatic activity against human cervix adenocarcinoma cell lines (HeLa) and human hepatocellular carcinoma cell lines (HepG-2). For further assessing apoptosis properties of complex 2, the levels of apoptosis were examined. The BSA-binding properties were investigated by means of fluorescence titration. The results indicate that complexes 1–4 could quench the intrinsic fluorescence of BSA.