Novel chelate complexes of Co(II), Ni(II), Cu(II), Pd(II) derived from anti- and syn-isomers of 2-(2-aminothiazole-4-yl)-2-hydroxyiminoacetic acid with pro-/antiproliferative actions on endothelial cells

摘要

Anti-and syn-isomers of 2-(2-aminothiazole-4-yl)-2-hydroxyiminoacetic acid (anti-A and syn-A respectively) were used as potential biologically active polydentate complexing agent for Co2+, Ni2+, Cu2+ and Pd2+ ions for the synthesis of novel complex compounds with directed angiogenesis-correcting action. It shown that the location of functional groups in ligand molecules, the electronic structure of metal as complexing agent and the synthesis conditions affect the localization of coordination bonds and the structure of formed complexes. The interaction of ethanol solutions of metal salts with anti-A and syn-A in an acidic medium at the component ratios M:L = 1:1 and 12 leads to the formation of complexes [Co(anti-A)(H2O)(3)SO4] (1); [Ni(anti-A)(H2O)(3)SO4] (2); [Cu(anti-A)(2)Cl-2] (3); [Pd(anti-A)(2)Cl-2] (4); [Cu(syn-A)(2)Cl-2] (5); [Pd(syn-A)Cl-2] (6) with different coordination of ligands. Coordination mode of ligands identified by IR, UV-Vis, XPS and H-1 (C-13) NMR spectra. The structures of salt of the anti-A and complexes 1, 2, 6 were determined by X-ray diffraction study. Anti-A is coordinated to metal ions in a chelate manner by the nitrogen atom of the hydroxylimino group and the oxygen atom of the deprotonated carboxyl group. In this case, the 2-aminothiazole fragment does not involve in complexation. Syn-A is coordinated to the central metal ion in neutral form through the nitrogen atoms of hydroxyimino group and thiazole ring. All synthesized complex compounds form stable solutions in neutral medium, which makes it possible to use them as potential biologically active substances.