Pentacoordinate zinc complexes of imidazole nitrogen donors as structural models for the active site in enzymes: preparation and crystal structures of (.mu.-2,2'-biimidazole)tetrakis(2,2'-biimidazole)dizinc(II) tetraperchlorate trihydrate and bis(2,2'-biimidazole)(formato)zinc(II) perchlorate

Abstract

291ChemInform Abstract The reaction of Zn perchlorate with the biimidazole ligand in water gives (I), crystallizing in the space group P212121 with Z=4. (II) is obtained from a hot solution (dioxane/water 1:1) containing Zn perchlorate, the ligand and formic acid, and crystallizes in the space group P21/c with Z=4. In both complexes Zn prefers a stoichiometric composition that enables five-coordination of the metal.Molecular units in (I) and (II) are linked by three-dimensional hydrogen bond networks. The metal environments of the complexes are relevant for the discussion of the active sites in zinc enzymes such as carboxypeptidase A; the importance of trigonal-bipyramidal five-coordinate intermediates for the catalytic action of Zn in enzymes is discussed (no yields given).

Syntheses, crystal structures and luminescent properties of two new 1D d10 coordination polymers constructed from 2,2′-bibenzimidazole and 1,4-benzenedicarboxylate

“…The broad absorption bands of 3328 and 3074 cm À1 for 1 and the 3448, 3134 and 3103 cm À1 for 2 in the IR spectra can be assigned to the n(N-H) stretching vibrations [17,21]. The coordination fashion of the H 2 BDC moiety to the metal atom in 1 and 2 is proved by the shifts of the stretching vibrations n as and n s of the carboxyl group.…”

Synthesis, crystal structure and nuclease activity of a new Mn(II) complex involving 2-(2-1H-imidazolyl)-1H-imdazolium ligand

“…The presence of an imidazole moiety in biological molecules has encouraged the studies of H 2 biim-containing transition metal complexes [24,25]. However, a few studies about the interaction between the transition metal complexes of 2,2′-biimidazole (Biim) and DNA have been reported, and most of the studies are limited in the structure characterization [26,27].…”

“…The presence of an imidazole moiety in biological molecules has encouraged the studies of H 2 biim-containing transition metal complexes [24,25]. However, a few studies about the interaction between the transition metal complexes of 2,2′-biimidazole (Biim) and DNA have been reported, and most of the studies are limited in the structure characterization [26,27].By these reasons, we aimed to discover a new DNA cleavage reagent containing Biim ligand. In this paper, a new Mn(II) complex of Mn(H 3 biim) 2 (NCS) 2 Cl 2 (H 3 biim_2-(2-1H-imidazolyl)-1H-imidazolium) was synthesized and characterized by elemental analyses and X-ray single crystal diffraction.…”

Synthesis, Crystal Structure, and DNA‐Binding Properties of a New Cd(II) Complex Involving 2‐(2‐1H‐Imidazolyl)‐1H‐Imdazolium Ligand

“…18,19 However, few studies about the interaction between the transition metal complexes of 2,2'-biimidazole (Biim) and DNA have been reported, and most of the studies are limited in the structure characterization. 20,21 By these reasons, we aimed to discover a new DNA binding and cleavage reagent containing Biim ligand. In this paper, the interaction of a novel Cd(II) complex involving 2-(2-1H-imidazolyl)-1H-imdazolium ligand with DNA has been investigated using electronic absorption spectroscopy, fluorescence spectroscopy, viscosity measurement and voltammetry.…”