Synthesis, crystal structure and anti-cancer activity of the complex chlorido-(η 2 -ethyl-ene)(quinolin-8-olato-κ 2 N , O )platinum(II) by experimental and theoretical methods.

The complex [Pt(C 9 H 6 NO)Cl(C 2 H 4 )], (I), was synthesized and structurally characterized by ESI mass spectrometry, IR, NMR spectroscopy, DFT calculations and X-ray diffraction. The results showed that the deprotonated 8-hy-droxy-quinoline (C 9 H 6 NO) coordinates with the Pt II atom via the N and O atoms while the ethyl-ene coordinates in the η 2 manner and in the trans position compared to the coordinating N atom. The crystal packing is characterized by C-H⋯O, C-H⋯π, Cl⋯π and Pt⋯π inter-actions. Complex (I) showed high selective activity against Lu-1 and Hep-G2 cell lines with IC 50 values of 0.8 and 0.4 µ M , respectively, 54 and 33-fold more active than cisplatin. In particular, complex (I) is about 10 times less toxic to normal cells (HEK-293) than cancer cells Lu-1 and Hep-G2. Furthermore, the reaction of complex (I) with guanine at the N7 position was proposed and investigated using the DFT method. The results indicated that replacement of the ethyl-ene ligand with guanine is thermodynamically more favorable than the Cl ligand and that the reaction occurs via two consecutive steps, namely the replacement of ethyl-ene with H 2 O and the water with the guanine mol-ecule.