S. I. Orysyk¹, G. G. Repich¹, O. O. Andrushchenko², V. V. Nikulina², V. V. Orysyk³, Yu. L. Zborovskii³,
L. V. Garmanchuk², V. I. Pekhnyo¹, O. V. Skachkova⁴, M. V. Vovk³

¹V. I. Vernadskii Institute of General and Inorganic Chemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: orysyk@ionc.kiev.ua;
²Educational and Scientific Centre “Institute of Biology” of Taras Shevchenko National University, Kyiv;
³Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kyiv;
⁴National Cancer Institute, Kyiv

Pd(II) and Ni(II) complex compounds: [Pd(AMMT)₂]Cl₂ (1), [Pd(AMMT)₄]Cl₂ (2) and [Ni(AMMT)₂(H₂O)₂](NO₃)₂ (3) with 4-amino-3-mercapto-5-methyl-1,2,4-triazole (AMMT) have been synthesized. The spectral characteristics of 1, 2 were studied by ¹H (¹³C) NMR and UV-Vis spectroscopy. X-ray diffraction studies established that all complexes contain the AMMT molecule, which are coordinated to the central metal ion in the thione tautomeric form. At the ratio M : L = 1 : 2 ligand is coordinated in bidentate chelate manner by the nitrogen of amino- and sulfur of mercapto group (compounds 1, 3). But the molar ratio M : L = 1 : 4 leads to monodentate coordination of AMMT molecules only by sulfur of mercaptogroup (complex 2). Vacant coordination sites of the metal ion are occupied by water molecules (complex 3). The screening of complexes 1−3 and starting compounds [АММТ, K₂PdCl₄ (4), Ni(NO₃)₂∙6H₂O (5)] by their mitochondrial dehydrogenase activity have been performed by us for the first time, resulting in established that the Pd(II) complexes (1, 2), Pd(II) salt (4) and AMMT normalize the activity of mitochondrial dehydrogenases of cancer HeLa cells, identified by MTT-test. In contrast, the Ni(II) complex (3) and Ni(II) salt (5) do not stimulate the activity of mitochondrial dehydrogenases. It has been found, that all investigated compounds do not affect on the cell cycle and the level of apoptotic cells as well as do not show a toxic effect. Thus, these results indicate that AMMT and Pd(II) complexes may be used as modifiers of mitochondrial respiration, which dysfunction is particularly evident in the tumor cells.