Syntheses, structures and anti-tumor activity of four new organotin(IV) carboxylates based on 2-thienylselenoacetic acid

With the 2-thienylselenoacetic acid ligand, four new organotin complexes, [Me3Sn(O2CCH2SeC4H3S-o)](n) (1), [(Ph3Sn)(6)(O2CCH2SeC4H3S-o)(6)] (2), [(Me2Sn)(4)(mu(3)-O)(2)(O2CCH2SeC4H3S-o)(4)] (3), and [(PhSn)(6)(mu(3)-O)(6)(O2CCH2SeC4H3S-o)(6)] (4), have been synthesized and characterized by X-ray crystallography, elemental analysis, FT-IR and NMR (H-1, C-13, and Sn-119) spectroscopy. The structure analysis indicates that complex 1 adopts a 1D infinite zig-zag chain structure, while complex 2 shows a centrosymmetric hexanuclear 24-membered macrocycle. In contrast, complex 3 and complex 4 display ladder and drum structures, respectively. Examination of the non-covalent intermolecular contacts in complex 3 reveals the existence of the C-H center dot center dot center dot O and C-H center dot center dot center dot pi interactions, which play an important function in the supramolecular construction. These compounds are rare examples of selenium carboxylic acid-based organotin derivatives. Furthermore, the anti-tumor activity of complexes 1-3 has also been studied. Importantly, the anti-proliferative properties and possible mechanism of complex 2 are preliminarily investigated. The results demonstrate that complex 2 could induce apoptotic cell death via accumulation of ROS and collapse of the mitochondrial membrane permeabilization (MMP).