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The title compound, C20H22O2, crystallizes with two independent molecules in the asymmetric unit. In each molecule, all the non-H atoms lie in a common plane (r.m.s. deviations of 0.098 and 0.079 Å). There is a [pi]-[pi] stacking interaction in the crystal structure. The central aromatic rings of the two molecules, which are stacked head-to-tail one above the other, are separated by centroid-to-centroid distances of 3.872 (13) and 3.999 (10) Å. Key indicators: single-crystal X-ray study; T = 173 K; mean σ(C–C) = 0.003 A° ; R factor = 0.044; wR factor = 0.101; data-to-parameter ratio = 14.6.
The title compound, C14H20O3, is a synthetic analogue with a long aliphatic side chain of the important food additive and flavoring agent, vanillin. There are two independent molecules in the asymmetric unit, each having an essentially planar conformation (r.m.s. deviations of 0.023 and 0.051Å for all non-H atoms of the two molecules in the asymmetric unit). Key indicators: single-crystal X-ray study; T = 173 K; mean σ(C–C) = 0.002 A°; R factor = 0.049; wR factor = 0.144; data-to-parameter ratio = 15.9.
The title compound, C22H28N2O6, crystallizes with four half-molecules in the asymmetric unit: each molecule is located about a crystallographic inversion centre. The central methylene groups of two molecules are disordered over two sets of equally occupied sites. The crystal packing is characterized by sheets of molecules parallel to (114).
4-(4-Nitrophenoxy)biphenyl
(2009)
The two phenyl rings of the biphenyl unit of the title compound, C18H13NO3, are almost coplanar [dihedral angle 6.70 (9)°]. The nitrophenyl ring, on the other hand, is significantly twisted out of the plane of the these two rings, making dihedral angles of 68.83 (4)° with the middle ring and 62.86 (4)° with the end ring. The nitro group is twisted by 12.1 (2)° out of the plane of the phenyl ring to which it is attached. Key indicators: single-crystal X-ray study; T = 173 K; mean σ(C–C) = 0.002 A° ; R factor = 0.040; wR factor = 0.118; data-to-parameter ratio = 12.8.
Large crystals of the methyl ester of the N-a-benzyloxycarbonyl protected Ala-Phe dipeptide (Z-AF-OMe) were obtained after the very slow evaporation of a solution of the corresponding carboxylic acid (Z-AF-OH) in methanol containing an excess of HCl. The structure was confirmed by single crystal X-ray diffraction data. It crystallizes in the orthorhombic space group P212121 with unit cell dimensions a = 5.0655(6) Å, b = 8.4614(8) Å, c = 46.856(5) Å, V = 2008.3(4) Å3, Z = 4. In the crystal, the molecules form hydrogen bonded chains running along the a axis of the unit cell. Other secondary interactions are also discussed.
In the title compound, C27H37N2 +·Cl−·2CH2Cl2, the cation and the anion are each located on a crystallographic mirror plane. Both of the dichloromethane solvent molecules show a disorder across a mirror plane over two equally occupied positions. Additionally, one isopropyl group is also disordered. In the crystal, the cations are connected to the chloride ions via C—H[cdots, three dots, centered]Cl hydrogen bonds.
The title solvated salt, C29H41N2+·Br-·2CH2Cl2 was obtained from the reaction of the Arduengo-type carbene 1,3-bis(2,6-diisopropylphenyl)-1,3-dihydro-4,5-dimethyl-2H-imidazol-2-ylidene with Si2Br6 in dichloromethane. The complete cation is generated by a crystallographic mirror plane and the dihedral angle between the five-membered ring and the benzene ring is 89.8 (6)°; the dihedral angle between the benzene rings is 40.7 (2)°. The anion also lies on the mirror plane and both dichloromethane molecules are disordered across the mirror plane over two equally occupied orientations. In the crystal, the cations are linked to the anions via C-H...Br hydrogen bonds.
In the title compound, C27H37N2 +·Br−·2CH2Cl2, both the cation and the anion are located on a crystallographic mirror plane. Both of the dichloromethane solvent molecules show a disorder across a mirror plane over two equally occupied positions. In the crystal, the cations are connnected to the bromide ions via C—H[cdots, three dots, centered]Br hydrogen bonds.
4-Nitrophenyl 1-naphthoate
(2010)
In the title compound, C17H11NO4, the dihedral angle between the two benzene rings is 8.66 (3)°. The nitro group is twisted by 4.51 (9)° out of the plane of the aromatic ring to which it is attached. The presence of intermolecular C—H ... O contacts in the crystal structure leads to the formation of chains along the c axis.
The title compound, C14H11NO4, crystallizes with two molecules in the asymmetric unit. The major conformational difference between these two molecules is the dihedral angle between the aromatic rings, namely 36.99 (5) and 55.04 (5)°. The nitro groups are coplanar with the phenyl rings to which they are attached, the O—N—C—C torsion angles being -1.9 (3) and 1.0 (3)° in the two molecules.