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Publications and source records attributed to Doyle Britton.
The structures of o-chlorobenzonitrile, C7H4ClN, (I), and o-bromobenzonitrile, C7H4BrN, (II), have similar packing arrangements, even though Z' = 4 in (I) and Z' = 1 in (II). Both structures involve X...N interactions, as well as weak C-H...X and C-H...N hydrogen bonds. The four crystallographically independent molecules in (I) are related by pseudosymmetry.
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The title compound, C8H5NO, has an intramolecular O...CN contact involving an O...C distance of 2.797 (2) angstroms and a C-C-N bond angle of 174.5 (2) degrees, both indicative of a weak nucleophilic attack of the aldehyde O atom on the electrophilic C atom in the nitrile group. Calculations at the B3LYP density functional level using the 6-31G* basis set support this interpretation; natural bond-order analysis indicates an n(O1) --> pi(CN)* delocalization energy of 6.3 kJ mol(-1). Similar results were obtained from density functional calculations on three related molecules. The 2-formylbenzonitrile molecules pack in sheets as a consequence of C-H...N and C-H...O hydrogen bonds.
The structures of dimethyldithiocyanatotin(IV), [Sn(CH3)2(NCS)2], and diethyldithiocyanatotin(IV), [Sn(C2H5)2(NCS)2], have been determined. The dimethyl derivative has 2mm crystallographic symmetry and the diethyl derivative has twofold crystallographic symmetry. The experimental differences in the distances and angles around the Sn atom between the two structures agree reasonably well with the differences expected from the reaction path mapped previously [Britton & Dunitz (1981). J. Am. Chem. Soc. 103, 2971-2979].
3,5-Dichloro-4-hydroxybenzonitrile and its solvates with benzene and xylene assemble in chain-like arrangements held together by OH...NC interactions. Two polymorphs each of the corresponding dibromo and diiodo compounds form similar chains which are then bound together by X...X interactions to form approximately planar sheets. These sheets are essentially identical in all four of the bromo and iodo compounds and have approximate p2gg two-dimensional symmetry. These four compounds form an extreme example of two-dimensional isostructuality. The polymorphs differ in the stacking arrangements. One of the Br polymorphs is isostructural with one of the I polymorphs.
2,3,5,6-Tetrachlorobenzene-1,4-dicarbonitrile forms alternate pi-stacked 1:1 complexes with pyrene, C(8)Cl(4)N(2).C(16)H(10), and phenanthrene, C(8)Cl(4)N(2).C(14)H(10). These complexes are pseudo-isomorphs. Phenanthrene, disordered about a centre of symmetry, takes the position of the pyrene, which sits exactly on this centre of inversion. The tetrachlorobenzenedicarbonitrile molecules in each complex also sit on centres of inversion and are in similar positions within the unit cells in the two structures, except that the orientation of the nitrile groups differs between the two.
The title compound, C13H9NO, crystallizes with four molecules in the asymmetric unit. Each of the four crystallographically independent molecules forms a chain parallel to the a axis with symmetry-equivalent molecules. These chains are held together by similar O-H...NC hydrogen bonds, with approximately linear O-H...N angles and significantly bent H...N-C angles. The four different molecules are related by strong elements of pseudosymmetry. To better describe the pseudosymmetry, the structure has been reported in the non-standard space group C-1.
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p-Decylphenyl isocyanide, p-C(10)H(21)-C(6)H(4)-NC or C(17)H(25)N, and p-decylbenzonitrile, p-C(10)H(21)-C(6)H(4)-CN or C(17)H(25)N, are isomorphous. The molecules lie in mirror planes, with the C(6) rings perpendicular to the mirror. The packing of both molecules includes an aliphatic region, with close to ideal packing of the C(10)H(21) chains, and an aromatic region, with phenyl ring-CN interactions. In addition, the CN ends of the molecules are also involved in a CN.NC dipolar interaction.
Diiododurene (1,4-diodo-2,3,5,6-tetramethylbenzene), C(10)H(12)I(2), packs with four molecules in the asymmetric unit. All four of these moleules violate Kitaigorodsky's suggestion that molecules with centers of symmetry will lie on crystallographic centers of symmetry. There is 5.6% disorder at one of the sites. Most of the I atoms are in contact with other I atoms, but only six of the I.I contacts are shorter than 4.2 A. Of these six contacts, one set of three contacts forms a triangular set in which all of the I.I distances are less than 3.9 A.
The title (1H-pyrrol-2-yl)pyridines, C(9)H(8)N(2), substituted at the ortho, meta, and para positions of the pyridine ring all have hydrogen-bonded arrangements with geometrically similar, nearly linear, N(pyrrole)-H...N(pyridine) hydrogen bonds of average length. The graph sets for the ortho, meta, and three para polymorphs are R(2)(2)(10), C(6), C(7), C(7), and R(4)(4)(28), respectively.
o-Benzenedicarbaldehyde (systematic name: benzene-1,2-dicarbaldehyde), C(8)H(6)O(2), 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), C(8)H(6)O(2), occurs as two different isomorphs. In all three crystals, there are intermolecular C-H.O contacts involving both aldehyde and ring H atoms.
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.
Cyanodimethylarsine, [As(CH(3))(2)(CN)], and cyanodimethylstibine, [Sb(CH(3))(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.
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-dibromobenzo[c]furazan 1-oxide, C(6)H(2)Br(2)N(2)O(2), (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.
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.
A new synthetic procedure developed recently in our laboratories has made possible the synthesis of variety of new complexes of CuCN with diamines. Synthesis was effected by adding the ligand to a solution of CuCN in aqueous sodium thiosulfate. This procedure also provides an alternative pathway to a novel diamine complex reported by us previously, (CuCN)(3)(HMTA)(2) (1) (where HMTA = hexamethylenetetramine). The other diamine ligands used were 1,4-diazabicyclo[2.2.2]octane (dabco), 1,4-dimethylpiperazine (dmpip), piperazine (pip), 1,4-butanediamine (butda), N,N,N',N'-tetramethylethylenediamine (tetmen), and N-phenylpiperazine (phpip). Complex2, Cu(2)(CN)(3)(dabco-H), crystallizes in the hexagonal space group P6(3) with unit cell dimensions a = 8.174(3) Å, c = 8.083(4) Å, and Z = 2. Complex 3, (CuCN)(2)(dmpip), crystallizes in the monoclinic space group C2/m with unit cell dimensions a = 8.812(3) Å, b = 9.631(2) Å, c = 7.266(3) Å, beta = 113.40(3) degrees, and Z = 2. Complex 4, (CuCN)(2)(pip), crystallizes in the monoclinic space group C2/c with unit cell dimensions a = 9.439(3) Å, b = 10.561(2) Å, c = 8.870(3) Å, beta = 98.32(3) degrees, and Z = 4. Complex 5, Cu(2)(CN)(3)(pip-H), crystallizes in the monoclinic space group C2/c with unit cell dimensions a = 20.573(9) Å, b = 8.354(2) Å, c = 15.989(6) Å, beta = 133.70(3) degrees, and Z = 8. Complex 6, (CuCN)(2)(butda), crystallizes in the monoclinic space group P2(1)/c with unit cell dimensions a = 10.456(2) Å, b = 5.550(1) Å, c = 8.669(3) Å, beta = 106.80(2) degrees, and Z = 2. Complex 7, (CuCN)(2)(tetmen), crystallizes in the orthorhombic space group Cmc2(1) with unit cell dimensions a = 11.889(4) Å, b = 33.380(8) Å, c = 9.012(3) Å, and Z = 12. Complex 8, (CuCN)(phpip), crystallizes in the monoclinic space group P2(1)/cwith unit cell dimensions a = 17.8819(3) Å, b = 6.9190(1) Å, c = 8.6972(1) Å, beta = 96.720(1) degrees, and Z = 4.
The syntheses and crystal structures of the first cyanide, sulfur mixed ligand copper(I) complexes are reported. The first complex of the family was discovered when (CuCN)(3)(C(6)H(12)N(4))(2) (1) (C(6)H(12)N(4) = hexamethylenetetramine) was treated with aqueous thiourea. The sulfur ligands include thiourea (tu), 1,3-dimethyl-2-thiourea (dmtu), 1,3-diethyl-2-thiourea (detu), 1,1,3,3-tetramethyl-2-thiourea (tmtu), and 2-imidazolidinethione (N,N'-ethylenethiourea, etu). Synthesis was effected by adding the ligand to a solution of CuCN in aqueous sodium thiosulfate. Complex 2, (CuCN)(2)(tu)(3)(H(2)O), crystallizes in the triclinic space group P&onemacr;with unit cell dimensions a = 7.696(5) Å, b = 9.346(2) Å, c = 10.772(2) Å, alpha = 106.53(2) degrees, beta = 91.11(4) degrees, gamma = 98.42(3) degrees, and Z = 2. Complex 3, (CuCN)(3)(dmtu)(2), crystallizes in the monoclinic space group Cc with unit cell dimensions a = 10.082(3) Å, b = 14.984(5) Å, c = 11.413(3) Å, beta = 104.50(2) degrees, and Z = 4. Complex 4, (CuCN)(2)(detu)(H(2)O), crystallizes in the monoclinic space group P2(1)/n with unit cell dimensions a = 7.969(5) Å, b = 11.559(4) Å, c = 13.736(5) Å, beta = 100.48(4) degrees, and Z = 4. Complex 5, (CuCN)(tmtu) (polymorph a), crystallizes in the orthorhombic space group P2(1)2(1)2(1) with unit cell dimensions a = 8.653(1) Å, b = 9.426(1) Å, c = 11.620(3) Å, and Z = 4. Complex 6, (CuCN)(tmtu) (polymorph b), which has the same connectivity as 5, crystallizes in the triclinic space group P&onemacr; with unit cell dimensions a = 9.660(4) Å, b = 14.202(4) Å, c = 16.03(1) Å, alpha = 101.68(5) degrees, beta = 107.08(6) degrees, gamma = 70.07(2) degrees, and Z = 8. The difference between the polymorphs is that 5 has a zig-zag chain with a repeat unit of two while 6 has a 4-fold helix. Complex 7, (CuCN)(2)(etu), crystallizes in the monoclinic space group P2(1)( )()with unit cell dimensions a = 3.994(2) Å, b = 13.886(3) Å, c = 7.556(1) Å, beta = 97.07(2) degrees, and Z = 2.