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The molecular structure of the title bis-pyridyl substituted diamide hydrate, C14H14N4O2·H2O, features a central C2N2O2 residue (r.m.s. deviation = 0.0205 Å) linked at each end to 3-pyridyl rings through methylene groups. The pyridyl rings lie to the same side of the plane, i.e. have a syn-periplanar relationship, and form dihedral angles of 59.71 (6) and 68.42 (6)° with the central plane. An almost orthogonal relationship between the pyridyl rings is indicated by the dihedral angle between them [87.86 (5)°]. Owing to an anti disposition between the carbonyl-O atoms in the core, two intramolecular amide-N—H...O(carbonyl) hydrogen bonds are formed, each closing an S(5) loop. Supramolecular tapes are formed in the crystal via amide-N—H...O(carbonyl) hydrogen bonds and ten-membered {...HNC2O}2 synthons. Two symmetry-related tapes are linked by a helical chain of hydrogen-bonded water molecules via water-O—H...N(pyridyl) hydrogen bonds. The resulting aggregate is parallel to the b-axis direction. Links between these, via methylene-C—H...O(water) and methylene-C—H...π(pyridyl) interactions, give rise to a layer parallel to (10\overline{1}); the layers stack without directional interactions between them. The analysis of the Hirshfeld surfaces point to the importance of the specified hydrogen-bonding interactions, and to the significant influence of the water molecule of crystallization upon the molecular packing. The analysis also indicates the contribution of methylene-C—H...O(carbonyl) and pyridyl-C—H...C(carbonyl) contacts to the stability of the inter-layer region. The calculated interaction energies are consistent with importance of significant electrostatic attractions in the crystal.

The asymmetric unit of the title 2:1 co-crystal, 2C8H8O2·C14H14N4O2, comprises an acid molecule in a general position and half a diamide molecule, the latter being located about a centre of inversion. In the acid, the carboxylic acid group is twisted out of the plane of the benzene ring to which it is attached [dihedral angle = 28.51 (8)°] and the carbonyl O atom and methyl group lie approximately to the same side of the molecule [hydroxy-O—C—C—C(H) torsion angle = −27.92 (17)°]. In the diamide, the central C4N2O2 core is almost planar (r.m.s. deviation = 0.031 Å), and the pyridyl rings are perpendicular, lying to either side of the central plane [central residue/pyridyl dihedral angle = 88.60 (5)°]. In the molecular packing, three-molecule aggregates are formed via hydroxy-O—H...N(pyridyl) hydrogen bonds. These are connected into a supramolecular layer parallel to (12\overline{2}) via amide-N—H...O(carbonyl) hydrogen bonds, as well as methylene-C—H...O(amide) interactions. Significant π–π interactions occur between benzene/benzene, pyridyl/benzene and pyridyl/pyridyl rings within and between layers to consolidate the three-dimensional packing.

The asymmetric unit of the title salt, C14H16N4O22+·2C9H5O6−, comprises half a dication, being located about a centre of inversion, and one anion, in a general position. The central C4N2O2 group of atoms in the dication are almost planar (r.m.s. deviation = 0.009 Å), and the carbonyl groups lie in an anti disposition to enable the formation of intramolecular amide-N—H...O(carbonyl) hydrogen bonds. To a first approximation, the pyridinium and amide N atoms lie to the same side of the molecule [Npy—C—C—Namide torsion angle = 34.8 (2)°], and the anti pyridinium rings are approximately perpendicular to the central part of the molecule [dihedral angle = 68.21 (8)°]. In the anion, one carboxylate group is almost coplanar with the ring to which it is connected [Cben—Cben—Cq—O torsion angle = 2.0 (3)°], whereas the other carboxylate and carboxylic acid groups are twisted out of the plane [torsion angles = 16.4 (3) and 15.3 (3)°, respectively]. In the crystal, anions assemble into layers parallel to (10-4) via hydroxy-O—H...O(carbonyl) and charge-assisted hydroxy-O—H...O(carboxylate) hydrogen bonds. The dications are linked into supramolecular tapes by amide-N—H...O(amide) hydrogen bonds, and thread through the voids in the anionic layers, being connected by charge-assisted pyridinium-N—O(carboxylate) hydrogen bonds, so that a three-dimensional architecture ensues. An analysis of the Hirshfeld surface points to the importance of O—H...O hydrogen bonding in the crystal structure.

The asymmetric unit of the title 2:1 co-crystal, 2C8H8O2·C14H14N4O2, comprises an acid molecule in a general position and half a diamide molecule, the latter being located about a centre of inversion. In the acid, the carboxylic acid group is twisted out of the plane of the benzene ring to which it is attached [dihedral angle = 28.51 (8)°] and the carbonyl O atom and methyl group lie approximately to the same side of the molecule [hydroxy-O-C-C-C(H) torsion angle = -27.92 (17)°]. In the diamide, the central C4N2O2 core is almost planar (r.m.s. deviation = 0.031 Å), and the pyridyl rings are perpendicular, lying to either side of the central plane [central residue/pyridyl dihedral angle = 88.60 (5)°]. In the molecular packing, three-molecule aggregates are formed via hydroxy-O-H···N(pyridyl) hydrogen bonds. These are connected into a supramolecular layer parallel to (122) via amide-N-H···O(carbonyl) hydrogen bonds, as well as methylene-C-H···O(amide) interactions. Significant π-π interactions occur between benzene/benzene, pyridyl/benzene and pyridyl/pyridyl rings within and between layers to consolidate the three-dimensional packing. [ABSTRACT FROM AUTHOR]

The asymmetric unit of the title salt, C14H16N4O22+.2C9H5O6-, comprises half a dication, being located about a centre of inversion, and one anion, in a general position. The central C4N2O2 group of atoms in the dication are almost planar (r.m.s. deviation = 0.009 Å), and the carbonyl groups lie in an anti disposition to enable the formation of intramolecular amide-N--H···O(carbonyl) hydrogen bonds. To a first approximation, the pyridinium and amide N atoms lie to the same side of the molecule [Npy--C--C--Namide torsion angle = 34.8 (2)°], and the anti pyridinium rings are approximately perpendicular to the central part of the molecule [dihedral angle = 68.21 (8)°]. In the anion, one carboxylate group is almost coplanar with the ring to which it is connected [Cben--Cben--Cq--O torsion angle = 2.0 (3)°], whereas the other carboxylate and carboxylic acid groups are twisted out of the plane [torsion angles = 16.4 (3) and 15.3 (3)°, respectively]. In the crystal, anions assemble into layers parallel to (104) via hydroxy-O--H···O(carbonyl) and charge-assisted hydroxy-O -- H···O(carboxylate) hydrogen bonds. The dications are linked into supramolecular tapes by amide-N--H···O(amide) hydrogen bonds, and thread through the voids in the anionic layers, being connected by charge-assisted pyridinium-N--O(carboxylate) hydrogen bonds, so that a three-dimensional architecture ensues. An analysis of the Hirshfeld surface points to the importance of O--H···O hydrogen bonding in the crystal structure. [ABSTRACT FROM AUTHOR]