Showing papers by "Doyle Britton published in 2002"
TL;DR: Seven polymorphic forms of the crystals of Ortho-, meta- and para-tetrachlorodicyanobenzene form 1/1 complexes with hexamethylbenzene (HMB), and six of the complexes involve layers of two-dimensional arrays.
Abstract: Ortho-, meta- and para-tetrachlorodicyanobenzene (TBD, tetrachlorobenzenedicarbonitrile) form 1/1 complexes with hexamethylbenzene (HMB) Seven polymorphic forms of the crystals, one of o-TDB, two of m-TDB and four of p-TBD, have been found All of the complexes involve layers of two-dimensional arrays, and in six of the complexes the layers are homogeneous, alternate layers being entirely TDB or entirely HMB The layers can be described in terms of an hexagonal tiling and in five of the homogeneous layers the TDB are ordered so that one CN and two Cl come together at each corner of the tiles In the sixth the m-TDB is disordered, but a plausible arrangement can still be found with one CN and two Cl coming together in the same fashion
10 citations
TL;DR: In this paper, the 1:1 complex between di-cyano-durene (2,3,5,6-tetra-methyl-1,4-benzodicarbo-nitrile), C12H12N2·C6F4I2, there are two major types of intermolecular interaction.
Abstract: In the crystal structure of the 1:1 complex between dicyanodurene (2,3,5,6-tetramethyl-1,4-benzodicarbonitrile) and p-tetrafluorodiiodobenzene (2,3,5,6-tetrafluoro-1,4-diiodobenzene), C12H12N2·C6F4I2, there are two major types of intermolecular interaction. The planar molecules are stacked alternately in the common charge-transfer arrangement with molecules 3.53 (3) A apart. In addition, the molecules form linear chains, driven by CN⋯I interactions, with a distance of 3.061 (3) A. The dicyanodurene and tetrafluorodiiodobenzene molecules lie on centers of symmetry.
7 citations
TL;DR: This work has confirmed that cyanodimethylarsine and Sb are closely related, but not isomorphous, crystal structures containing XCN.
Abstract: Cyanodimethylarsine, [As(CH3)2(CN)], and cyanodimethylstibine, [Sb(CH3)2(CN)], have closely related, but not isomorphous, crystal structures containing XCN⋯XCN⋯ chains. The N⋯As distance of 3.185 (3) A is slightly shorter than the expected van der Waals distance of 3.5 A, while the N⋯Sb distance of 2.862 (9) A, compared with the expected value of 3.7 A, is much shorter. This is consistent with Sb being a stronger Lewis acid than As.
6 citations
TL;DR: In this paper, a weak intramolecular hydrogen bond between an aldehyde H atom and the O atom of the adjacent Aldehyde group, with a C⋯O distance of 2.852
Abstract: o-Benzenedicarbaldehyde (systematic name: benzene-1,2-dicarbaldehyde), C8H6O2, exhibits a weak intramolecular hydrogen bond between an aldehyde H atom and the O atom of the adjacent aldehyde group, with a C⋯O distance of 2.852 (2) A. m-Benzenedicarbaldehyde (systematic name: benzene-1,3-dicarbaldehyde), C8H6O2, occurs as two different isomorphs. In all three crystals, there are intermolecular C—H⋯O contacts involving both aldehyde and ring H atoms.
3 citations
TL;DR: The title compound, C7H3F2N, packs with slightly puckered molecular sheets [moltexules tilted by 8.1° with respect to the sheets] and two of the H atoms in the moltex are in contact with N atoms in adjacent molecules as mentioned in this paper.
Abstract: The title compound, C7H3F2N, packs with slightly puckered molecular sheets [molecules tilted by 8.1 (1)° with respect to the sheets]. Two of the H atoms in the molecule are in contact with N atoms in adjacent molecules, while the remaining H atom is in contact with two F atoms in adjacent molecules.
2 citations
TL;DR: In this article, the title compound, C8H4N2, is isomorphous with p-di-cyano-benzene and is end-for-end disordered.
Abstract: p-Dicyanobenzene and p-diisocyanobenzene are not isomorphous. The title compound, C8H4N2, is isomorphous with p-dicyanobenzene. The molecule lies on a center of symmetry and is end-for-end disordered. The bond lengths and angles lie within normal ranges, but the precise values are obscured by the disorder.
2 citations
TL;DR: In the low-temperature form of the bromo compound the layers have shifted relative to each other by approximately 0.7 A in y, and the disorder, which is still present after the transition, decreases as the temperature is lowered.
Abstract: At room temperature the two title compounds are isomorphous. Both have a disordered structure that includes a major component, one of the title compounds, and a minor component, the 6-halo isomer, occurring at the same site in the crystal. When the chloro compound is cooled to as low as 98 K, there is no change in the structure and no significant change in the degree of disorder. When the bromo compound is cooled, it undergoes a second-order phase transition at 282 K to a second polymorph, structurally very similar, but with two molecules in the asymmetric unit. In both isomorphs and both polymorphs the molecules occur in two-dimensional layers that are essentially the same. In the low-temperature form of the bromo compound the layers have shifted relative to each other by approximately 0.7 A in y. In the low-temperature form the disorder, which is still present after the transition, decreases as the temperature is lowered.
1 citations
TL;DR: C7H2Br2FN as discussed by the authors is a compound that packs in approximately planar sheets with molcellules held together in pairs by intermolecular Lewis acid-base interactions across a center of symmetry.
Abstract: The title compound, C7H2Br2FN, packs in approximately planar sheets with molecules held together in pairs by CN⋯Br intermolecular Lewis acid–base interactions across a center of symmetry. The CN⋯Br arrangement is approximately linear at the Br atom and bent at the N atom, with an N⋯Br distance of 3.11 A. The molecular pairs form sheets through C—H⋯N hydrogen bonds, with H⋯N distances of 2.55 A, and C—H⋯F hydrogen bonds with H⋯F distances of 2.68 A.
1 citations
TL;DR: The molecular structures of 4,7-dichlorobenzo[c]furazan 1-oxide, C(6)H( 2)Cl(2)N(2]O(2), (I), and 4, 7-dibromobenzos[c], (II), are normal, and the two polymorphs comprise a set of three two-dimensional polymorphic arrangements.
Abstract: The molecular structures of 4,7-dichlorobenzo[c]furazan 1-oxide, C6H2Cl2N2O2, (I), and 4,7-dibromobenzo[c]furazan 1-oxide, C6H2Br2N2O2, (II), are normal. Compound (I) occurs in two polymorphic forms. One polymorph contains one molecule in the asymmetric unit, organized into two-dimensional sheets involving intermolecular N⋯Cl and O⋯Cl interactions. The second polymorph has three molecules in the asymmetric unit, organized into two crystallographically different two-dimensional sheets with similar interactions. Compound (II) is isomorphous with the second polymorph of (I). The three two-dimensional sheets in the two polymorphs comprise a set of three two-dimensional polymorphic arrangements.
1 citations