Synthesis, characterization and <i>in vitro</i> cytotoxicity of platinum(II) complexes of selenones [Pt(selenone)<sub>2</sub>Cl<sub>2</sub>]

<p>Platinum(II) complexes with various selenones (L) having the general formula [PtL<sub>2</sub>Cl<sub>2</sub>] were prepared and characterized by elemental analysis and, IR and NMR (<sup>1</sup>H, <sup>13</sup>C, and <sup>77</sup>Se) spectroscopies. A decrease in the IR frequency of the >C=Se mode and an upfield shift in <sup>13</sup>C NMR for the >C=Se resonance of selenones are consistent with their selenium coordination to platinum(II). The NMR data show that the complexes are stable in solution and do not undergo equilibration at 297 K. The geometrical structures of the complexes were predicted theoretically (with DFT method) using Gaussian09 program. DFT calculations predicted that the <i>trans</i> configurations were up to 1.7 kcal/mol more stable than the <i>cis</i> forms in gas phase, while in solution form the <i>cis</i> isomers were predicted to be more stable. The UV–vis spectra of the two complexes, <b>6</b> and <b>7</b> were also recorded at room temperature for 24 h and it was observed that the complexes were stable and did not undergo decomposition. The <i>in vitro</i> antitumor properties of the complexes as well as of cisplatin were evaluated on two human cancer cell lines, HeLa (cervical cancer cells) and MCF7 (breast cancer cells) using MTT assay. The results indicated that the prepared complexes exerted significant inhibition on the selected cancer cells.</p>