Synthesis, structure and anticancer activity of three platinum(II) complexes with 2-phenylpyridine derivatives

Three luminescent Pt(II) complexes, [Pt(5-NO₂-ppy)(H-5-NO₂-ppy)(Cl)] (1), [Pt(2-(2′,4′-dF)-ppy)(H-2-(2′,4′-dF)-ppy)(Cl)] (2), [Pt(2-(3′,5′-dF)-ppy)(H-2-(3′,5′-dF)-ppy)(Cl)] (3) with 2-phenyl-5-nitropyridyl (5-NO₂-ppy), 2-(2,4-difluorophenyl)pyridine (2-(2′,4′-dF)-ppy) and 2-(3,5-difluorophenyl)pyridine(2-(3′,5′-dF)-ppy) were synthesized. FT-IR spectroscopy, multinuclear NMR spectroscopy and single-crystal X-ray crystallography were used to determine their structures. The UV–vis absorption and photoluminescence (PL) spectra of 1–3 were measured. 1–3 displayed rich photophysical properties with the maximum emission wavelengths in the range of 403 to 527 nm in the photoluminescence spectra, which demonstrated 1–3 have the potential to become the DNA luminescent probes in living cells. The anticancer activities of these complexes were tested in vitro by MTT assay against four tumor cell lines BGC823, MGC803 (human gastric cancer cell lines), HepG2 (human hepatocellular carcinoma), A549 (human non-small-cell lung cancer cell lines), HL-7702(human normal liver cell line). Moreover, 3 displayed highest cytotoxicity against human gastric cancer cell lines with the values of IC₅₀ in the range of 13.036–26.594 μM.