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The title compound. C15H14N2O4, (I), has a gauche–gauche (O/C/C/C—O/C/C/C or GG) conformation and is a positional isomer of propane-1,3-diyl bis(pyridine-3-carboxylate), (II). The molecule of (I) lies on a twofold rotation axis, which passes through the central C atom of the aliphatic chain, giving one half-molecule per asymmetric unit. There is excellent agreement of the geometric parameters of (I) and (II). The most obvious differences between them are the O/C/C/C—O/C/C/C torsion angles [56.6 (2)° in (I) and 174.0 (3)/70.2 (3)° in (II) for GG and TG conformations, respectively] and the dihedral angle between the planes of the aromatic rings [80.3 (10)° in (I) and 76.5 (3)° in (II)]. The crystal structure is stabilized by weak C—H ... N and C—H ... O hydrogen bonding.
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, C6H5NO2·C6H6O2, crystallizes with one pyridinium-2-carboxylate zwitterion and one molecule of benzene-1,2-diol in the asymmetric unit. The crystal structure is characterized by alternating molecules forming zigzag chains running along the a axis: the molecules are connected by O—H ... O and N—H ... (O,O) hydrogen bonds.
Crystals of the title compound, C12H8N2·C7H8O2, were obtained during cocrystallization experiments of a compound with two hydrogen-bond donors (2-hydroxybenzyl alcohol) with another compound containing two hydrogen-bond acceptors (phenanthroline). Unexpectedly, the two molecules do not form dimers with two O—H ... N hydrogen bonds connecting the two molecules. However, one of the hydroxy groups forms a bifurcated hydrogen bond to both phenanthroline N atoms, whereas the other hydroxy group forms an O—H ... O hydrogen bond to a symmetry-equivalent 2-hydroxybenzyl alcohol molecule. In addition, the crystal packing is stabilized by Pi – Pi interactions between the two phenanthroline ring systems, with a centroid–centroid distance of 3.570 Å.
In the crystal of the title compound [systematic name: 2-(3,5-diamino-6-chloropyrazin-2-ylcarbonyl)guanidinium chloride methanol disolvate], C6H9ClN7O+·Cl-·2CH3OH , the components are connected by N—H ... N, N—H ... Cl, N—H ... O, O—H ... Cl and O—H ... O hydrogen bonds into a three-dimensional network. The dihedral angle between the aromatic ring and the guanidine residue is 6.0 (2)°.
In contrast to the previous structure determinations of the title structure, (NH4)2[MoS4], the present determination at 173 K localized the positions of the H atoms. The title structure belongs to the beta-K2SO4 family and all the ions are located on crystallographic mirror planes. The ions are held together by N—H ... S hydrogen bonds (some of which are bifurcated), forming a three-dimensional network. One of the N atoms has nine contacts to the S atoms shorter than 4 Å, and the other has ten.
The title compound (also know as azorellanone), C20H32O2, is built up from three fused carbocycles, one five-membered ring and two six-membered rings. The five membered-ring has an envelope conformation, whereas the six-membered rings have a distorted half-chair and a twist–boat conformation. In the crystal, molecules are linked by O—H ... O interactions into zigzag chains with graph-set notation C(8) along [010]. The absolute configuration was assigned on the basis of earlier chemical studies.
The dihydropyrimidine ring of the title compound, C13H15ClN2S, adopts an envelope conformation with five almost coplanar atoms (r.m.s. deviation = 0.054 Å) and the C atom bearing the two methyl substituents deviating from this plane by 0.441 (2) Å. The best plane through the five almost coplanar atoms forms a dihedral angle of 89.56 (5)° with the benzene ring. The crystal packing is characterized by centrosymmetric dimers connected by pairs of N—H ... S hydrogen bonds.