Ab initio Hartree-Fock molecular orbital calculations were applied to the crystalline imidazole and its derivatives in order to examine systematically the effect of possible N–H·· ·N type hydrogen bonding on the nuclear quadrupole interaction parameters in these materials. The nitrogen quadrupole coupling constant (QCC) and the asymmetry parameter ( ) of the electric field gradient (EFG) were f...

Resonance Raman spectroscopy is employed to characterize heme site structural changes arising from conformational heterogeneity in deoxyMb and ligated derivatives, i.e., the ferrous CO (MbCO) and ferric cyanide (MbCN) complexes. The spectra for the reversed forms of these derivatives have been extracted from the spectra of reconstituted samples. Dramatic changes in the low-frequency spectra are...

IR spectroscopic investigations were conducted with poly-L-histidine (PLH) films, hydrous imidazole and pyrazole solutions and anhydrous ./V-methylimidazole with respect to protonation. Continuous absorption arises with increasing protonation and is maximally intensive with PLH, imidazole and 7V-methylimidazole when 50% protonated. The absorption indicates the formation of N H ® # , , N bonds. ...

Metal-mediated base pairs represent a powerful tool for the site-specific functionalization of nucleic acids with metal ions. The development of applications of the metal-modified nucleic acids will depend on the availability of structural information on these double helices. We present here the NMR solution structure of a self-complementary DNA oligonucleotide with three consecutive imidazole ...

Two highly efficient protocols for the regioselective synthesis of 2-substituted 4-alkenyl- and 4-aryl-1,2,3-triazoles by the palladium-catalyzed C-H functionalization of 1,2,3-triazole N-oxides are reported. A possible pathway of direct alkenylation with 1-octene and vinyl acetate is discussed.

Photopolymers are interesting materials for use in recording information in holography. We study the holographic behavior and stability of volume holograms recorded in poly(vinyl alcohol)--acrylamide photopolymers with and without a cross linker. Using a first-harmonic diffusion model, we analyze the residual monomer that remains when volume diffraction gratings are recorded in photopolymer mat...

The centrosymmetric mol-ecule of the title complex, [Cd(4)Cl(8)(C(3)H(4)N(2))(6)(C(3)H(7)NO)(2)], contains four Cd(II) atoms, six imidazole, two dimethyl-formamide and eight chloride ligands. The structure shows a novel chloride-bridged tetra-nuclear cadmium quasi-cubane cluster. The coordination geometry of all Cd(II) atoms is distorted octa-hedral, with the two metal atoms in the asymmetric u...

The crystal structure of the title compound, C(15)H(11)FN(6)S, forms a three-dimensional network stabilized by π-π inter-actions between the imidazole core and the tetra-zole ring of the tetra-zolopyridine-unit; the centroid-centroid distance is 3.627 (1) Å. The crystal structure also displays bifurcated N-H⋯(N,N) hydrogen bonding and C-H⋯F inter-actions. The former involve the NH H atom of the...

The title compound, [Fe(C(5)H(3)N(2)O(4))(2)(H(2)O)(2)], is a triclinic modification of a monoclinic form recently reported by Du et al. [Acta Cryst. (2011) ▶, E67, m997]. The Fe(II) ion lies at an inversion center and is coordinated by two N and two O atoms from two 5-carb-oxy-1H-imidazole-4-carboxyl-ate ligands in trans positions, together with two water mol-ecules, completing a slightly dist...

In the title coordination polymer, {[Zn(C(9)H(7)NO(4))(C(10)H(14)N(4))]·2H(2)O}(n), the Zn(II) ion displays a distorted tetra-hedral geometry with two imidazole N atoms from two 1,1'-(butane-1,4-di-yl)bis-(imidazole) (bbi) ligands and two carboxyl-ate O atoms from two 2,6-dimethyl-pyridine-3,5-dicarboxyl-ate (dpdc) ligands. The bbi and dpdc ligands bridge the Zn(II) ions, forming layers paralle...