Copper coordination compounds with (5 Z ,5 Z ')-2,2'-(alkane-α,ω-diyldiselenyl)-bis-5-(2-pyridylmethylene)-3,5-dihydro-4 H -imidazol-4-ones. Comparison with sulfur analogue.

A series of new organic ligands (5 Z ,5 Z ')-2,2'-(alkane-α,ω-diyldiselenyl)-bis-5-(2-pyridylmethylene)-3,5-dihydro-4 H -imidazol-4-ones (L) consisting of two 5-(2-pyridylmethylene)-3,5-dihydro-4 H -imidazol-4-one units linked with polymethylene chains of various lengths ( n = 2-10, where n is the number of CH 2 units) have been synthesized. The reactions of these ligands with CuCl 2 ·2H 2 O and CuClO 4 ·6H 2 O gave Cu 2+ or Cu 1+ containing mono- and binuclear complexes with Cu 2 LCl x ( x = 2-4) or CuL(ClO 4 ) y ( y = 1, 2) composition. It was shown that the agents reducing Cu 2+ to Cu 1+ in the course of complex formation can be both a ligand and an organic solvent in which the reaction is carried out. This fundamentally distinguishes the selenium-containing ligands L from their previously described sulfur analogs, which by themselves are not capable of reducing Cu 2+ during complexation under the same conditions. A higher cytotoxicity and reasonable selectivity to cancer cell lines for synthesized complexes of selenium-containing ligands was shown; unlike sulfur analogs, ligands L themselves demonstrate a high cytotoxicity, comparable in some cases to the toxicity of copper-containing complexes.