1H NMR study of interactions between cisplatin and N-allyl-2-thiohydantoin type ligand

Abstract

cis-Diamminedichloridoplatinum(II) or cisplatin, cis-[PtCl2(NH3)2], is the one of most widely used anticancer drug. Its effectiveness against various cancer types is well established. Despite its remarkable pharmacological activity, the drug presents considerably disadvantages such as non-selectivity and high toxicity. Sulfur-containing molecules have a high affinity for platinum and could form stable bonds. On other side, thiohydantoin derivatives have potential biological and medicinal activity such as antiviral, antifungal and anticonvulsant activity. The metal complexes of thiohydantoins are biologically active molecules. Coordination of these compounds with well-known anticancer metal-based drugs could be important strategy in the development of new anticancer agents. Since N-allyl-2-thiohydantoin type ligand, 5-[2-(methylthio)ethyl]-3-(2-propen-1-yl)-2-thioxo-4-imidazolidinone, has several nucleophilic groups and could act as effective polydentate ligand towards metal ions, the mechanism of its interactions with cis- [PtCl2(NH3)2] was investigated by 1H NMR spectroscopy under second-order conditions with an initial molar ratio of complex to thiohydantoin concentration of 1:1. The results have shown high affinity of investigated N-allyl-2-thiohydantoin type ligand for cisplatin. According to hard-soft acid-base principle, platinum(II) has a remarkable affinity for sulphur- and nitrogen-bonding nucleophiles.