Wearing Surface Testing: Yukon River Bridge

INE/AUTC 12.2

(E)-1-(4-Nitrophenyl)-2-(4-{[(E)-2-(4-nitrophenyl)hydrazinylidene]met hyl}benzylidene)hydrazine dihydrate

The 30 non-H atoms in title dihydrazine compound, C(20)H(16)N(6)O(4)center dot 2H(2)O, are close to coplanar, the r.m.s. deviation for these atoms being 0.096 angstrom. The conformation about each of the C=N bonds is E, and the molecule has non-crystallographic 2/m symmetry. The presence of O-H center dot center dot center dot O and N-H center dot center dot center dot O hydrogen bonding leads to a three-dimensional network in the crystal structure. A highly disordered solvent molecule is present within a molecular cavity defined by the organic and water molecules. Its contribution to the electron density was removed from the observed data in the final cycles of refinement and the formula, molecular weight and density are given without taking into account the contribution of the solvent molecule

Bis(mu-diphenylarsine-kappa As-2:As)bis[tetracarbonyltungsten(0)]

The title compound, [W-2(C12H10As)(2)(CO)(8)], features a diamond-shaped W2As2 core with a W-W distance of 3.0948 (7) angstrom. The coordination geometry for each W atom is based on a pentagonal bipyramid within a As2C4W donor set, with carbonyl ligands defining the axial positions; the As atoms exist within distorted tetrahedral C2W2 donor sets

A doubly interpenetrated layer structure: 4-Acetamidobenzaldehyde 4-Nitrophenylhydrazone

The title molecule, 4-acetamidobenzaldehyde 4-nitrophenylhydrazone, is essentially planar with the maximum deviations from the least-squares plane through the 22 non-hydrogen atoms being 0.176(1)angstrom (nitro-O) and -0.152(1) angstrom(amide-O). The dihedral angle between the benzene rings is 6.93(7)degrees. The conformation about the C=N bond is E. The presence of amide-H center dot center dot center dot O-nitro and hydrazine-H center dot center dot center dot O-amide hydrogen bonding leads to the formation of zigzag 2-D arrays with a pseudo three-connected brick-wall network when viewed normal to the plane of the layer. The layers are sustained by 38-membered {center dot center dot center dot OCNC5N2C4NO center dot center dot center dot HNCO center dot center dot center dot HN2C5NH center dot center dot center dot ONC4NH} synthons and the rather large voids defined by these are occupied by a centrosymmetrically related layer to result in the formation of a doubly interpenetrated network. These stack along the b direction being connected by C-H center dot center dot center dot O interactions. The compound crystallizes in the monoclinic space group P2(1)/c with a = 10.8152(3) angstrom, b = 10.9469(2) angstrom, c = 12.9198(4) angstrom, beta = 113.679(1)degrees, and Z = 4

N-(4-Bromophenyl)-2-(2-thienyl)acetamide

The thienyl ring in the title compound, C(12)H(10)BrNOS, is disordered over two diagonally opposite positions, the major component having a site-occupancy factor of 0.660 (5). The molecule is twisted as evidenced by the dihedral angles of 70.0 (4) and 70.5 (6)degrees formed between the benzene ring and the two orientations of the disordered thiophene ring. Linear supramolecular chains along the a axis are found in the crystal structure through the agency of N-H center dot center dot center dot O hydrogen bonding

7-Chloro-4-[(E)-N `-(4-fluorobenzylidene)hydrazinyl]quinoline monohydrate

The molecule of the title hydrate, C(16)H(11)ClFN(3)center dot H(2)O, is slightly twisted, as indicated by the dihedral angle of 9.55 (10)degrees formed between the quinoline ring system and the benzene ring. The conformation about the C=N double bond is E, and the amine-H atom is oriented towards the quinoline residue. In the crystal structure, the water molecule accepts an N-H center dot center dot center dot O and makes two O-H center dot center dot center dot N quinoline hydrogen bonds, generating a two-dimensional array in the ab plane, which is further stabilized by C-H center dot center dot center dot O interactions. The most significant contacts between layers are of the type C-H center dot center dot center dot F

N-(4-Bromophenyl)pyrazine-2-carboxamide

The molecule of the title compound, C11H8BrN3O, is close to planar (r.m.s. deviation of all 16 non-H atoms = 0.103 angstrom), a conformation stabilized by an intramolecular N-H center dot center dot center dot N hydrogen bond, which generates an S(5) ring. In the crystal structure, supramolecular chains mediated by C-H center dot center dot center dot O contacts (along a) are linked into a double layer via N center dot center dot center dot Br halogen bonds [3.207 (5) angstrom] and C-Br center dot center dot center dot pi interactions [Br center dot center dot center dot ring centroid(pyrazine) = 3.446 (3) angstrom]. The layers stack along the b axis via weak pi-pi interactions [ring centroid(pyrazine)center dot center dot center dot ring centroid(benzene) distance = 3.803 (4) angstrom]

Triclinic form of bis{di-mu-hydroxidobis[fac-aquatribromidotin(IV)]} heptahydrate

The asymmetric unit of the title hydrate, 2[Sn(H2O)(2)(OH)(2)Br-6]center dot 7H(2)O, comprises two [Br-3(H2O) Sn(mu-OH)(2)SnBr3(OH2)] units, but three independent molecules as two of these are disposed about inversion centres, and seven water molecules. In common with the monoclinic polymorph [Howie et al. (2005). Inorg. Chim. Acta, 358, 3283-3286], each of the dinuclear species features a central Sn2O2 core, distorted octahedral Sn atom geometries defined by a Br3O3 donor set, and an anti-disposition of the coordinated water molecules. In the crystal, O-h-H center dot center dot center dot O-w, O-a-H center dot center dot center dot O-w, O-w-H center dot center dot center dot O-w, and O-w-H center dot center dot center dot Br (h = hydroxyl, a = aqua, w = water) hydrogen-bonding interactions generate a three-dimensional network

N-(4-Chlorophenyl)-1,1,1-trifluoro-N-(trifluoromethylsulfonyl)methanesul fonamide

The title molecule, also called 4-chloro-N,N-bis(trifluoromethanesulfonyl)aniline, C8H4ClF6NO4S2, has non-crystallographic twofold symmetry with the pseudo-axis aligned along the Cl-C center dot center dot center dot C-N backbone of the molecule: the SO2CF3 residues lie to either side of the benzene ring. In the crystal, the presence of C-H center dot center dot center dot O contacts lead to the formation of a sequence of 12-membered {center dot center dot center dot HC2NSO}(2) synthons within a supramolecular chain aligned along [101]

2-Chloro-6,6-dimethyl-5,6-dihydroindazolo[2,3-c]quinazoline

Two independent but virtually identical molecules comprise the asymmetric unit of the title compound, C16H14ClN3. The molecules have a slightly curved shape owing to puckering in the six-membered C4N2 ring; the respective dihedral angles formed between the benzene rings are 12.64 (7) and 11.72 (7)degrees. In the crystal, layers sustained by a combination of N-H center dot center dot center dot N hydrogen bonding as well as C-H center dot center dot center dot N and C-H center dot center dot center dot pi contacts are formed; these stack along [011] and are connected by further C-H center dot center dot center dot pi contacts