Organotin(IV) complexes derived from 1,4-naphthalenedicarboxylic acid: synthesis, structure, in vitro cytostatic activity

Seven organotin(IV) complexes, [(R3Sn)2L]n (R = Me 1, R = n-Bu 2), [(Ph3Sn)2L] (3), [(R2Sn)2L(μ3-O)]n (R = Me 4, R = n-Bu 5), [R2SnL(1,10-phen)]n (R = Me 6), [(R2SnCl)2L(1,10-phen)2] (R = n-Bu 7) derived from 1,4-naphthalenedicarboxylic acid (H2L) have been synthesized and characterized by elemental analysis, FT-IR, PXRD, NMR and X-ray crystallography. The single crystal diffraction reveals that complexes 1 and 2 represent 2D network structures, which both contain tetranuclear 26-membered macrocycles. Complexes 3 and 7 display dinuclear tin monomers, which can form 1D infinite chain by C-H···O and C-H···π interactions. Meanwhile, complexes 4 and 5 display 2D network containing tetraorganodistannoxane unit, while complex 6 adopts a 1D infinite chain structure, which further constructs 2D supramolecular architecture through C-H···O intermolecular interactions. What's more, in vitro cytostatic activity of the complexes 1-3 against cervical carcinoma cell lines (HeLa), hepatocellular carcinoma cell lines (HepG-2) and human normal breast cell lines (HBL-100) have been investigated, and the results show that organotin derivatives with n-butyl and phenyl group (2 and 3) exhibit significantly higher anticancer activity than complex 1 with methyl group. Meanwhile, organotin(IV) complexes (1-3) display lower cytotoxicity than corresponding organotin(IV) precursors [trimethyltin chloride, bis(tri-n-butyltin) oxide and triphenyltin chloride] in HBL-100 cells. Furthermore, cytostatic assessments of complex 3 against HepG-2 cells reveal that the effect of cytostatic and apoptotic may through ROS-mediated pathway.