Exploration of the influence of 5-iodo-2'-deoxyuridine incorporation on the structure of d[CACG(IDU)G]

The first antiviral nucleoside 5-iodo-2'-deoxyuridine (IDU) against herpes simplex virus type 1 and type 2 is a thymidine analogue, i.e. the C5 methyl group is replaced by an I atom. The structure of the self-complementary hexamer d[CACG(IDU)G] was determined by single-crystal X-ray diffraction techniques. The orthorhombic crystals belong to space group P2(1)2(1)2(1), with unit-cell parameters a = 18.16, b = 30.03, c = 41.99 Angstrom. Refinement in the resolution range 20 - 1.3 Angstrom converged with a final R1 = 0.167, including 43 water molecules and two cobalt hexammine complexes. The incorporation of a large I atom has only minor consequences for the overall structure as is noticed in the IDU . A base pairs, which are of the common Watson - Crick type. To contribute to the still puzzling mechanism of this historically important agent, details of base stacking, helical parameters, hydration etc. have been studied. A general scheme of cobalt hexammine-binding modes in Z-DNA is provided, revealing similar binding modes for the reported structure

Exploration of triple-helical fragments : crystallization and preliminary X-ray diffraction of d(TGGCCTTAAGG)

The nonamer d(GCGAATTCG) and decamer d(GGCCAATTGG), containing one and two overhanging guanines, respectively, form G (.) GC triplets in their crystal packing. In order to introduce a third subsequent T (.) AT triplet, the decamer was further extended by one overhanging thymine residue. Two different crystal morphologies of the sequence d(TGGCCTTAAGG) were obtained by hanging-drop vapour diffusion and diffracted to 2.5 and 2.3 angstrom resolution, respectively. However, both crystals belong to the orthorhombic space group P2(1)2(1)2(1), with similar unit-cell parameters. Therefore, the two data sets could be merged to a resolution of 2.4 angstrom with unit-cell parameters a = 26.97, b = 41.12, c = 52.72 angstrom

Poly[µ2-L-alanine-µ3-nitrato-sodium(I)]

The title compound, [Na(NO3)(C3H7NO2)](n), was obtained unintentionally as the product of an attempted reaction of sodium molybdate in aqueous solution and the amino acid L-alanine ( ala), in order to obtain a gamma-type octamolybdate, Na-4[Mo8O26(ala)(2)].18H(2)O, coordinated by L-alanine. The coordination geometry around the Na atom can be considered as trigonal-bipyramidal, with three bidentate nitrate anions coordinating through their O atoms and two L-alanine molecules each coordinating through one carboxylate O atom

Dichlorido-[2-(2,6-diethylphenyl)iminomethylquinoline-N,N’]palladium(II) acetonitrile monosolvate

The title complex, [PdCl2(C20H20N2)] CH3CN, was synthesized by the reaction of 2-[(2,6-diethylphenyl)iminomethyl]quinoline with dichlorido(cycloocta-1,5-diene)palladium(II) in dry CH2Cl2. The PdII ion is coordinated by two N atoms of the bidentate quinoline ligand and by two chloride anions, generating a distorted square-planar coordination geometry around the metal centre. There is a detectable trans influence for the chloride ligands. The crystal packing is characterized by – stacking between the quinoline rings. The use of acetonitrile as the crystallization solvent was essential for obtaining good-quality crystals.Web of Scienc

Structures of 2,5-diaryl- and 2,3,5,6-tetra[3,2-b]thiophene synthesized by the palladium-catalyzed Suzuki-Miyaura cross-coupling reaction

The crystal structures of 2,5-di(ethoxyphenyl)-3,6-dibromothieno[3,2-b]thiophene (I) and 2,5-di(ethoxyphenyl)-3,6-diphenylthieno[3,2-b]thiophene (II) have been studied in order to evaluate the planarity of these molecules. The aromatic systems introduced to the thieno[3,2-b]thiophene core structure show a degree of rotation from 30.94° to 66.56°. The crystal packing of (I) are characterized by π×××π stacking, while in (II), C-H×××p and C-H×××O interactions are observed

Redetermination of {5-[(7-chloro­quinolinium-4-yl)amino]-2-hy­droxy­benz­yl}diethyl­ammonium dichloride dihydrate

The structure of the title compound (common name: amodiaquinium dichloride dihydrate), C20H24ClN3O2 +·2Cl−·2H2O, was previously determined from powder diffraction data [Llinàs et al. (2006 ▶). Acta Cryst. E62, o4196-o4199]. It has now been refined from diffractometer data to a significantly higher precision. The dihedral angle between the quinoline and benzene rings is 54.57 (6)°. The central amino N atom inter­acts more strongly with the quinoline ring than with the benzene ring, as indicated by the shorter C—N bond length [1.341 (2) Å compared to 1.431 (2) Å]. In the crystal, mol­ecules are packed into a three-dimensional network/supra­molecular structure through hydrogen bonds between the amodiaquinium cations, chloride anions and water mol­ecules

Tris(1-ethyl-3-methyl­imidazolium) hexa­bromidoeuropate(III)

The crystal structure of the title compound, (C6H11N2)3[EuBr6], consists of 1-ethyl-3-methyl­imidazolium cations and centrosymmetric octa­hedral hexa­bromido­europate anions. The [EuBr6]3− anions are located at the corners and face-centres of the monoclinic unit cell. Characteristic hydrogen-bonding inter­actions can be observed between the bromide anions and the acidic H atoms of the imidazolium cations