Synthesis, Structure, and Cytotoxicity of Pd(II) and Cu(II) Complexes with 1-Terpenyl-3-Thiosemicarbazides of Pinane and para-Menthane Series

PdL^1,2Cl₂·H₂O (I, II) and CuL¹Cl₂·H₂O (III) complexes (L¹ and L² are 1-terpenyl-3-thiosemicarbazides of pinane and para-menthane series, respectively) are obtained. Single crystals of complexes I and [PdL³Cl₂] (IV) (L³ is the product of hydrochlorination of ligand L²) have been grown. According to XRD data, crystal structures of I, IV consist of complex cations [PdLCl]⁺ and outer-sphere anions Cl⁻. The coordination polyhedron N₂SCl is a distorted square. L¹ and L³ are tridentate ligands. Free ligands L¹, L² and complexes I-III are studied using IR spectroscopy; conclusions on the structure of the Cu(II) complex are inferred from the analysis of obtained data. Cytotoxic properties of L¹, complexes I and III, as well as the carboplatin pharmaceutic are studied on the Hep2 (human larynx carcinoma) cell line. Complexes I and III are shown to be moderately cytotoxic: they are twice as less toxic with respect to Hep2 cells than carboplatin that is used in the experiment as the reference complex.