Metal(II) complexes with monodentate S and N ligands as structural models for zinc-sulfur DNA-binding proteins

摘要

The reaction of several metal salts with various amounts of the monodentate ligands N-(2-thiophenyl)-2,5-dimethylpyrrole (H-tpdp) and N-methylimidazole in the presence of a base provided a series of novel complexes. They are of the general formulas [M~(II)(tpdp)_4]~(2-), [M~(II)(tpdp)_2(N-MeIm)_2] (M = Zn, Co, Cd) and [M~(II)(tpdp)_3(N-MeIm)]~- (M = Zn, Co). The products were characterized by X-ray structure analyses as well as by elemental analyses and infrared spectroscopy, and for cobalt complexes by additional UV-Vis spectroscopy. Crystallographic parameters: [Et_3NH]_2[Zn(tpdp)_4] centre dot MeCN (1), [Et_3NH]_2[Co(tpdp)_4] centre dot MeCH (2), [Zn(tpdp)_2(N-MeIm)_2] (6) and [Co(tpdp)_2(N-MeIm)_2] (7) are monoclinic, space group P2_1/c, with Z = 4; [Cd(tpdp)_2(N-MeIm)_2] (8) is monoclinic, space group P2_1, with Z = 4; [Ph_4P]_2[Cd(tpdp)_4] (3), [Me_4N][Zn(tpdp)_3(N-MeIm)] (4), and [Me_4N][Co(tpdp)_3(N-MeIm)] (5) are triclinic, space group P1-bar, with Z = 2. All compounds have tetragonally compressed metal cores. The complexes are significant as models for many zinc-containing DNA-binding proteins.