Tetrakis(thione)platinum(II) complexes: synthesis, spectroscopic characterization, crystal structures, and <i>in vitro</i> cytotoxicity

<div><p>A new series of platinum(II) complexes based on thione ligands with general formula [Pt(thione)₄]X₂ (X⁻ = Cl⁻, NO₃⁻) has been synthesized and characterized using CHNS elemental analysis, infrared, ¹H and ¹³C solution-state NMR as well as ¹³C and ¹⁵N solid-state NMR spectroscopy, and X-ray crystallography. The spectroscopic methods confirm the coordination of Pt(II) with thiocarbonyl groups via sulfur of the thione ligands. The X-ray structures showed a distorted square planar geometry for <b>1</b>, [Pt(MeImt)₄]Cl₂ (MeImt = N-Methylimidazolidine-2-thione) while the hydrogen bonding interactions in <b>7</b>, [Pt(<i>i</i>PrImt)₄](NO₃)₂·0.6(H₂O) induce a bent see-saw distortion relative to the ideal square planar geometry. The <i>in vitro</i> cytotoxicity studies showed that <b>2</b>, [Pt(EtImt)₄]Cl₂ is generally the most effective, a two-fold better cytotoxic agent than cisplatin and carboplatin against MCF7 (human breast cancer).</p></div