Synthesis,structure, and in vitro cytotoxicity of organoplatinum(II) complexes containing aryl olefins and quinolines

Ten new organoplatinum(II) complexes, PtCl(Saf)(8-OQ)] (1), Pt(Saf-1H)(8-OQ)] (2), PtCl(Meug)(8-OQ)] (3), Pt(Meug-1H)(8-OQ)] (4), PtCl(Meteug)(8-OQ)] (5), PtCl(Meteug)(Q)] (6), Pt(Meteug)(Q-COO)] (7), Pt(Eteug-1H)(Q)] (8), Pt(Eteug-1H)(8-OQ)] (9), and Pt(Eteug-1H)(Q-COO)] (10) (where Saf = safrole, Meug = methyleugenol, Meteug = methyl eugenoxyacetate, Eteug = ethyl eugenoxyacetate, Q = quinoline, 8-OQ = 8-hydroxyquinolinate, and Q-COO = quinolin-2-carboxylate), were synthesized and characterized by spectroscopic methods. The position of N and O donors of quinoline ligands in comparison with the ethylenic double bond and the aromatic C5 of the aryl olefins in platinum(II) coordination sphere of 1–10 was determined using their NOESY spectra and confirmed by single-crystal X-ray diffraction of 10. Complexes 1, 2, 3, 4, and 9 exhibit impressive activities on four human cancer cell lines KB, Hep-G2, Lu, and MCF7 with IC₅₀ = 1.4–9.6 μM. Complexes 1, 2, 4, and 9 gave better antitumor activity than cisplatin against examined cell lines.