Synthesis, X-ray crystal structure, thermal behavior and evaluation as an in vitro cytotoxic agent of a tin(IV) complex containing dipicolinic acid

Abstract

Coordination compound (dmapH)2[Sn(pydc)3]·2H2O (where pydc is pyridine-2,6-dicarboxylate and dmapH is 4-dimethylaminopyridine) was prepared from the reaction between the proton-transfer compound, [dmapH]2[pydc2−] and SnCl4·5H2O metal salt. The structure was fully characterized by single-crystal X-ray diffraction and distorted tricapped triangular prism geometry was realized for it. The thermal behavior of the complex was investigated by TGA-DTA analyses. Then, inhibitory effect of both the complex and its ligand was tested, using oxaliplatin as a standard, under MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) method, against U251 (a human glioblastoma), H1299 (a human non-small cell lung carcinoma), βTC (a mouse beta pancreatic), A431 (an epidermoid carcinoma) and HFF (a human foreskin fibroblast) cell lines. Potent and selective anti-proliferative effect of the complex (IC50 = 1 μM, MAE = 65.32%) and also intense decrease of mitochondrial membrane potential (MMP) was exhibited on A431 cells. Evaluation of reactive oxygen species (ROS) in cited cells confirmed that apoptotic pathway may be a possible mode for the death of cells. In order to evaluate the cellular internalization potential of the complex, A431 cells were incubated with it at IC50 concentration. The recorded fluorescent images confirmed successful penetration of the complex.