Gur Dayal Nigam

2-Aminopyrimidine-fumaric acid cocrystal

In crystals of the title compound, 2-aminopyrimidin-1-ium hemifumarate hemifumaric acid, C 4 H 6 N 3 + -0.5C 4 H 2 O 4 2- .0.5C 4 H 4 O 4 , the asymmetric unit contains one 2-aminopyrimidine cation, C 4 H 6 N 3 + , protonated at a pyrimidine ring-N atom, one half-molecule of fumaric acid, C 4 H 4 O 4 , and one half of a fumarate ion, C 4 H 2 O 4 2- . These are linked by N-H...O, O-H...O and relatively strong C-H...O bonds, resulting in eight- and nine-membered hydrogen-bonded rings and an extended supramolecular structure.

2-Aminopyrimidine–terephthalic acid (1:1) complex

Mutual recognition of 2-aminopyrimidine, C 4 H 5 N 3 , and terephthalic acid, C 8 H 6 O 4 , is possible through the formation of cyclic eight-membered hydrogen-bonded rings in the co-crystal. Each molecule can participate in two such hydrogen-bonded ring patterns, and these result in infinite hydrogen-bonded zigzag chains.

2-Aminopyrimidine and p-phenylenediacetic acid (1:1) co-crystal

In the title co-crystal, each 2-aminopyrimidine molecule, C 4 H 5 N 3 , participates in two eight-membered hydrogen-bonded rings with carboxylic acid groups from two different phenylenediacetic acid molecules, C 10 H 10 O 4 . This results in infinite hydrogen-bonded chains. In the supramolecular structure, the chains are held together by weak C-H...O contacts.

N-(3-Hydroxyphenyl)-p-toluenesulfonamide

In the title compound, C 13 H 13 NO 3 S, the dihedral angle between the toluene and phenol moieties is 69.48 (5)°. The molecules form columns linked by N-H...O and O-H...O hydrogen bonds.

1,4-Methano-11a-methyl-4,4a,11,11a-tetrahydro-1H-benzo[b]fluoren-11-one.

The title compound, C(19)H(16)O, crystallizes with two molecules of opposite chirality in the asymmetric unit. In both molecules, the naphthalene and cyclopentanone moieties are individually planar. The two cyclopentane rings adopt envelope conformations, while the cyclohexane ring adopts a boat conformation.

2-Acetylamino-6-methylpyridine N-oxide monohydrate

In the title molecule, C 8 H 10 N 2 O 2 .H 2 O, the acetylamino group forms a dihedral angle of 6.05 (6)° with the pyridine ring. The N-H…O, O-H…O and C-H…O hydrogen bonds, along with π-π stacking interactions, are involved in the formation of a supramolecular assembly, with the water molecule acting as a bridging ligand.

5-Nitroisophthalic acid hydrate

In the title compound, C 8 H 5 NO 6 .H 2 O, the carboxylic acid groups are coplanar with the phenyl ring, whereas the nitro group is twisted from it by 26.1 (3)°. In the crystal, the molecules are linked by O.H...O hydrogen bonds through the water molecules and by weak CH...O hydrogen bonds involving the nitro groups, to form infinite zigzag sheets.

Diethyl 5-Oxo-1-phenyl-3-(2-thienyl)pyrrolidine-2,2-dicarboxylate, C20H21NO5S

The possibility of the 180° rotation of the thiophene ring is observed. The phenyl ring is almost perpendicular to the pyrrolidine ring. The structure is stabilized by van der Waals interactions.

Methyl (SR)-10-chloro-1,2,3,4,5,6-hexahydro-6-hydroxy-8-methoxy-1-methyl-1,9-phenanthroline-6-carboxylate.

In the title compound, C(16)H(19)ClN(2)O(4), the pyridine ring is nearly planar, the piperidine ring is non-planar and the cyclohexane ring adopts a screw-boat conformation. The carboxylate group makes a dihedral angle of 80.9 (2) degrees with the least-squares plane through the cyclohexane ring.

Trimethyl (5SR,6SR)-1,3-dichloro-8-diethylamino-5,6-dihydro-5-hydroxyisoquinoline-5,6,7-tricarboxylate

The title compound, C 19 H 22 C 12 N 2 O 7 , has four independent molecules in the asymmetric unit with no pseudosymmetry. In each of the four molecules the fused cyclohexadiene ring adopts a skew-boat conformation, with two of the three methoxycarbonyl groups in the axial orientation and the third methoxycarbonyl and the diethylamino groups attached equatorially. The hydroxyl groups are involved in O-H…O intermolecular hydrogen bonds with carbonyl-O atoms to form infinite chains in the [210] direction.