July 1998 issue
cif-access (inorganic compounds)
cif-access (metal-organic compounds)
The repeating unit in this polymeric structure involves both thiourea ligands and one 2-fluorobenzoate ligand. The Pb atom is coordinated by four O atoms from three 2-fluorobenzoate ligands and four S atoms from four thiourea ligands. The Pb⋯Pb separation is 3.74 Å. The many hydrogen bonds include three-centered hydrogen bonds involving C-F bonded F atoms.
cif-access (organic compounds)
The structure of the cholic acid–methanol–water inclusion complex is similar to that of cholic acid with methanol [Jones & Nassimbeni (1990). Acta Cryst. B46, 399-405]. The methanol guest is hydrogen bonded to the water molecule, which in turn participates in hydrogen bonds with three of the cholic acid O atoms.
Cedranediol, (1R,2R,5S,7R,8R,9S)-2,6,6,8-tetramethyltricyclo-[5.3.1.01,5]undecane-8,9-diol, has been synthesized and characterized by X-ray diffraction analysis. It is a new chiral auxiliary for asymmetric homologation.
The title compound, synthesized from the [2+2] cycloaddition of dichloroketene with 1-(benzoyloxy)methyl-3-methyl-2-butene, is shown to have the benzoyloxymethyl group at the 4 position. The cyclobutanone ring is puckered with a 28.6(2)° fold angle.
The N-H group of the title molecule forms an intramolecular N-H⋯N hydrogen bond [N⋯N 2.836 (3) Å] and is shielded from possible intermolecular acceptors by the SiMe3 groups.
The azapurine base has a slight butterfly shape with a 4.0 (3)o interplanar angle between the five-membered triazolo and six-membered pyrimidine rings. The β-D-xylopyranosyl ring has a 4C1 conformation.
The pyrrolidine ring has a twist conformation with a pseudo-twofold axis passing through the N atom. The crystal packing is stabilized by an intermolecular hydrogen bond.
Ta4O(Te2)4TeI4 contains Ta4O clusters in the form of distorted oxygen-centred tetrahedra. Neighbouring pairs of Ta4O clusters are linked by a μ4 Te atom to form a one-dimensional chain structure.
Hexakis(tetratelluriotantalum) tetraiodide hexaiodotantalate has a [TaTe4]n chain structure with TaI6− complex anions and I− anions between the chains. The [TaTe4]n chain contains rectangular antiprismatic TaTe8 polyhedra, each Ta atom being coordinated by four Te2 groups.
The single crystal of CO2 at 1.00 (5) GPa pressure exhibits Pa-3 symmetry with a = 5.4942 (2) Å and a C-O bond length of 1.168 (1) Å (corrected for thermal motion effects). The study demonstrates that an earlier claim of a new dry ice II phase at this pressure is unfounded.