Synthesis, structural and spectral characteristics of novel n,π-chelate complexes of Pd(II) and Pt(II) with N-allylthioureas and their influence on the growth of spheroids cells MCF-7 and GGT activity

Four mononuclear n,π-chelate complexes [M(HL1,2)Cl2] (M = Pd2+, Pt2+) have been obtained by the reactions of PdCl2 or K2[PtCl4] with N,N-diethyl-N’-(2-propenyl)thiourea (HL1) or N-cyclohexyl-N’-(2-propenyl)thiourea (HL2) in the presence of HCl. According to X-ray diffraction study, the molecules of HL1,2 are coordinated in a bidentate manner with the formation of six-membered chelate metallocycles in a twist-boat conformation. The diagonal arrangement of “soft-hard” donor atoms (S–M􀀀 Cl, C–M􀀀 Cl) in the coordination sphere leads to the Pearson’s effect of “molecular antisymbiosis in the trans effect” that causes the formation of complexes with an M:L ratio of 1:1. However, interaction in the ratio 1:2, 1:3 is also possible in the solution under the conditions of monodentate coordination of HL1 and HL2. All compounds were investigated by IR, UV–vis and NMR spectra. The 1H/13C NMR study showed that this method is reliable for establishing the formation of a π-coordinating bond. The similarity of the synthesized complexes structure with cisplatin implies the same mechanism of their antitumor action. Thus, it was investigated their effect on the growth and biochemical characteristics of human breast adenocarcinoma cells MCF-7 (grown in three-dimensional culture as spheroids) and the activity of the enzyme gamma-glutamyl transpeptidase (GGT). The results showed that all studied π-complexes are more active compared to cisplatin, and they exhibit pronounced anti-metastatic and pro-apoptotic activity, which one is caused by their inhibitory effect.

Svitlana I. Orysyk, Yurii L. Zborovskii, Viktor V. Orysyk, Liudmyla V. Garmanchuk, Polina V. Borovyk, Svitlana V. Shishkina, Olha Pavliuk, Vasyl I. Pekhnyo, Mykhailo V. Vovk. Synthesis, structural and spectral characteristics of novel n,π-chelate complexes of Pd(II) and Pt(II) with N-allylthioureas and their influence on the growth of spheroids cells MCF-7 and GGT activity. Polyhedron. 2023. Volume 231, 1 February, 116272 https://doi.org/10.1016/j.poly.2022.116272