From proton transferred to cyclometalated platinum(IV) complex: Crystal structure and biological activity

A new proton transfer complex of [6,6'-dmbipy.H](2)[PtCl6] (1) was prepared from the reaction of H2PtCl6 center dot 6H(2)O with 6,6'-dimethyl-2,2'-bipyridine (6,6'-dmbipy) in CH3CN at room temperature. The cyclometalated complex of mer-IPt(6,6'-dmbipy-x2N,C)Cl-3(DMF-xO)] (2) was prepared from the recrystallization of complex 1, in a mixture of DMF/DMSO/H2O (6:2:1) at 60 degrees C, in which the first C-H bond activation in a bipyridine ring with Pt(IV) ion was observed. In vitro cytotoxicity against four cultures: NIH-3T3, Caco-2, HT-29 and T47D were studied using MIT assays. Interestingly, compound 2 is more potent in killing a colon cancer cell line than cisplatin, since it exhibits extensively less toxicity on normal cells. Both complexes were characterized by elemental analysis, FT-IR, 1H NMR, UV Vis spectra and X-ray crystallography. (C) 2015 Elsevier B.V. All rights reserved.