Synthesis, structural characterization, formation constants and in vitro cytotoxicity of phenanthroline and imidazolidine-2-thione copper(II) complexes

The synthesis, crystal structures, physicochemical properties and complex formation constants of [Cu(phen)2(L)](ClO4)2 complexes, where phen is 1,10-ortho-phenanthroline and L is a series of substituted imidazolidine-2-thione, have been studied. Single crystal X-ray diffraction revealed a distorted trigonal–bipyramidal geometry for all the molecules. The complex formation constants were determined in nonaqueous media by spectrophotometric measurements. Testing copper(II) complexes in mouse neuroblastoma N2a cells persistently infected with the 22L strain of the scrapie prion protein (22L-N2a) resulted in high cytotoxicity but no antiprion activity at nontoxic doses.

Graphical abstractThe synthesis, structures and complex formation constants of C1 = [Cu(phen)2(2-imidazolidinethione)](ClO4)2, C2 = [Cu(phen)2(1-methyl-2-imidazolidinethione)](ClO4)2, C3 = [Cu(phen)2(1,3-dimethyl-2-imidazolidinethione)](ClO4)2, C4 = [Cu(phen)2(1-ethyl-2-imidazolidinethione)](ClO4)2 and C5 = [Cu(phen)2(1,3-diethyl-2-imidazolidinethione)](ClO4)2 complexes have been studied. Testing complexes in mouse neuroblastoma infected with strain of scrapie prion protein (22L–N2a) resulted in high cytotoxicity. Correlation between cytotoxicity and formation constants has been evaluated. phen=1,10-ortho-phenantroline, C0 = Cu(phen)2(ClO4)2.Figure optionsDownload full-size imageDownload as PowerPoint slide