Synthesis, Crystal Structures, In Vitro Cytostatic Activity and DFT Studies of Four Organotin(IV) Complexes Derived From Schiff-Base Carboxylic Acid

Four triorganotin(IV) complexes, [(Ph3Sn)2L] (1), [(Et3Sn)2L]n (2), [(Me3Sn)2L] n (3), [(Me3Sn)3L(mu 2-OH)] n (4) [H2L = 5-[(9-anthracenylmethylene)amino]-isophthalic acid], have been synthesized and characterized by elemental analysis, FT-IR, NMR spectroscopy and X-ray crystallography. DFT calculations were performed to calculate HOMO-LUMO energy gap and Mulliken charges of selected compounds. Single crystal diffraction reveals that complex 1 displays a dinuclear tin monomer. Complex 2 exhibits a 2D network structure with a tetranuclear 24-membered macrocycle. Similarly, complex 3 presents a 2D network structure containing two macrocycles, a dinuclear 16-membered macrocycle and a tetranuclear 32-membered macrocycle. Complex 4 presents a one-dimensional wireless chain that can form a 2D network structure through pi - pi interactions. The cytotoxic activities of the complexes 1-4 were investigated against HeLa, Hct-116, and A549 cancer cell lines and a normal cell line (LO2). Meanwhile, the anticancer mechanism of complex 1 was studied, and the results showed that complex 1 can increase intracellular reactive oxygen species, decline mitochondrial membrane potential (MMP), which may lead to apoptosis.