Synthesis, characterization and cytotoxic activity of tioconazole coordination compounds with nickel(II), palladium(II) and platinum(II)

Abstract

Coordination compounds of nickel(II), palladium(II) and platinum(II) with tioconazole (tcnz) were synthesized and characterized by infrared, UV-Vis-NIR, elemental analysis, molar conductivity, magnetic susceptibility, mass spectrometry, NMR spectroscopy and X- ray diffraction. Tioconazole presented a monodentate coordination mode, through the nitrogen atom of the imidazolic ring. The NiII compounds stabilized an octahedral geometry. In [Ni(tcnz)2(NO3)2].H2O the coordinated nitrate presented a bidentate coordination mode, while for the [Ni(tcnz)2(OAc)2].3H2O compound, the acetate behaves as a bridging ligand. When different molar ratios were used on the reaction synthesis, three or six ligands were coordinate to the nickel(II) atom, [Ni(tcnz)3Br2(H2O)], [Ni(tcnz)6]Cl2 and [Ni(tcnz)6]Br2. The palladium(II) and platinum(II) compounds, [Pd(tcnz)2Cl2], [Pt(tcnz)2Cl2].2H2O and [Pd(tcnz)2(OAc)2], stabilized a trans-square planar geometry. The compounds [Ni(tcnz)6]X2 give place to 3D supramolecular arrangements through hydrogen bonding (X∙∙∙H, X = Cl and Br) and p∙∙∙p stacking interactions, between the six membered rings of neighbouring molecules. The in vitro cytotoxic activity of the synthesized compounds was studied in four different human carcinoma cell lines: HCT-15 (colon), HeLa (cervix-uterine), MCF-7 (breast) and PC-3 (prostate).