Trupta Kaulgud

Persistence of the {…HOCO…HCN} heterosynthon in the co-crystals formed between anthranilic acid and three bipyridine-containing molecules

Abstract Co-crystals formed between anthranilic acid and each of 4,4′-bipyridine (1), 1,2-trans-1,2-bis(4-pyridyl)ethene (2) and 1,2-bis(4-pyridyl)ethane (3) have been formed from solutions containing 2:1 stoichiometric quantities of the reagents. Each structure features a centrosymmetric three-molecule aggregate mediated by O—H…N(pyridyl) hydrogen bonds indicating the robustness of the seven-membered {…HOCO…HCN} heterosynthon. The structures of (1)–(3) are isomorphous whereby the three-molecule aggregates are connected into flattened helical chains by amino-N—H…O(carbonyl) hydrogen bonds; the chains are consolidated into the three-dimensional structure by π…π interactions. The magnitude of the O—H…N hydrogen bonds in (1)–(3) are correlated with the basicity of the pyridine residue.

4-Amino-N-(4,6-dimethyl­pyrimidin-2-yl)benzene­sulfonamide–benzoic acid (1/1)

The constituents of the title co-crystal, C12H14N4O2S·C7H6O2, are connected by an eight-membered hetero-synthon {⋯NCNH⋯OCOH}, whereby the carboxylic acid forms donor and acceptor hydrogen bonds with a pyrimidine N atom and the adjacent amine, respectively. The dimeric aggregates thus formed are arranged in rows with their terminal NH2 groups forming N—H⋯O hydrogen bonds with neighbouring aggregates to form a two-dimensional array in the ac plane with an overall T-shaped topology. Layers interdigitate along the b axis being connected by C—H⋯O, C—H⋯π and π–π [centroid–centroid distance = 3.6316 (19) Å] interactions.

2 : 1 Co-crystals of p-nitrophenylacetic acid with three isomeric n-pyridinealdazines, n = 2, 3 and 4, featuring the {… HOCO … N(py)} heterosynthon

Abstract Crystal and molecular structures of 2 : 1 co-crystals formed between p-nitrophenylacetic acid and three isomeric n-pyridinealdazines, n = 2(1), 3(2) and 4(3), are described in which the carboxylic acid is always in a general position and the respective n-pyridinealdazine is located about a centre of inversion. A common feature of the supramolecular aggregation is the formation of three-molecule aggregates sustained by the {… HOCO … N(py)} heterosynthon, further vindicating this as a most reliable synthon for co-crystal design. Molecules are assembled into three-dimensional architectures by C–H … O interactions coupled with C–H … π (1) or π … π (2 and 3) contacts.

4-Aza-1-azoniabicyclo­[2.2.2]octa­ne–2-amino­benzoate–2-amino­benzoic acid (1/1/1)

A 4-aza-1-azoniabicyclo[2.2.2]octane cation, a 2-aminobenzoate anion and a neutral 2-aminobenzoic acid molecule comprise the asymmetric unit of the title compound, C6H13N2 +·C7H6NO2 −·C7H7NO2. An intramolecular N—H⋯O hydrogen bond occurs in the anion and in the neutral 2-aminobenzoic acid molecule. The cation provides a charge-assisted N—H⋯O hydrogen bond to the anion, and the 2-aminobenzoic acid molecule forms an O—H⋯N hydrogen bond to the unprotonated amino N atom in the cation. In this way, a three-component aggregate is formed. These are connected into a three-dimensional network by amino–carboxylate N—H⋯O hydrogen bonds. N—H⋯N hydrogen bonds are also observed.

1:1 Co-crystals of sulfadimidine with three bipyridine- type molecules: Persistence of N H N hydrogen bonded supramolecular chains.

Abstract The crystal and molecular structures of 1:1 cocrystals formed between sulfadimidine and each of three bipyridine-type molecules, namely 4,4′-bipyridine (1), 4- [(E)-2-(pyridin-4-yl)ethenyl]pyridine (2) and 4-[2-(pyridin- 4-yl)ethyl]pyridine (3), are described; 1 and 2 were characterised as acetone hemi-solvates. A common feature of the sulfadimidine molecules is the adoption of a shape approximating the letter L. Conformational variability of sulfadimidine as well as in the bipyridine-type molecules is highlighted. The common feature of the crystal packing is the formation of non-linear supramolecular chains sustained by amino- and amide-H…N(pyridyl) hydrogen bonds

tert-But­yl(2-hy­droxy­eth­yl)aza­nium 4-[(1,3-thia­zol-2-yl­aza­nid­yl)sulfon­yl]aniline

Two pairs of independent cations and anions comprise the asymmetric unit of the title salt, C6H16NO+·C9H8N3O2S2 −. The cations are virtually superimposable and each exhibits a gauche disposition of the hydroxy O and ammonium N atoms [the O—C—C—N torsion angles are 55.5 (3) and 57.5 (3)°]. Significant differences are seen in the molecular structures of the anions as seen in the S—N—C—S [1.1 (3) and 32.9 (3)°] and C—S—N—C [−69.7 (2) and 91.4 (2)°] torsion angles. Despite the variations in conformation, intramolecular hypervalent S⋯O interactions persist in each anion [3.078 (2) and 2.8730 (19) Å]. In the crystal, supramolecular double layers are formed in the bc plane, being sustained by O—H⋯N, N—H⋯O and N—H⋯N hydrogen bonding. These are connected along the a axis via C—H⋯O interactions.

Benzoic acid-2,9-dimethyl-phenanthroline (1/1).

The constituents of the title 1:1 co-crystal, C7H6O2·C14H12N2, are connected into dimeric aggregates by a bifurcated O—H⋯N hydrogen bond; the hydroxyl-H atom is hydrogen bonded to the two N atoms of the 2,9-dimethylphenanthroline. The hydrogen-bonded residues are almost orthogonal to each other [dihedral angle = 78.56 (7) °]. In the crystal packing, the aggregates are assembled into layers in the bc plane by π⋯π interactions [ring centroid⋯ring centroid distance = 3.5577 (16) Å] involving the pyridyl rings, and C–H⋯π contacts involving the phenanthroline-H atom and the phenyl ring of the acid.

Benzoic acid-2-{(E)-[(E)-2-(2-pyridyl-methyl-idene)hydrazin-1-yl-idene]meth-yl}pyridine (2/1).

The asymmetric unit of the title cocrystal, C12H10N4·2C7H6O2, comprises a single molecule of benzoic acid and one half-molecule of 2-pyridinealdazine situated about a centre of inversion. The carboxyl group is coplanar with the benzene ring to which it is connected [O—C—C—C = −172.47 (12)°] and similarly, the 2-pyridinealdazine molecule is planar (r.m.s. deviation of the 16 non-H atoms = 0.017 Å). In the crystal, molecules are connected into a non-planar three-molecule aggregate [dihedral angle between the benzene and pyridyl ring connected by the hydrogen bond = 61.30 (7)°] with a twisted Z-shape. Layers of 2-pyridinealdazine molecules in the ab plane are sandwiched by benzoic acid molecules being connected by O—H⋯N and C—H⋯O interactions, the latter involving the carbonyl O atom so that each benzoic acid molecule links three different 2-pyridinealdazine molecules. Interdigitated layers stack along the c axis.

2-Phenyl­acetic acid–(E,E)-4,4’-(hydra­zinediylidene)dipyridine (2/1)

The asymmetric unit of the title co-crystal, C12H10N4·2C8H8O2, comprises a single molecule of 2-phenylacetic acid and half a molecule of 4-pyridinealdazine as this is situated about a centre of inversion. Molecules are connected into a three component aggregate via O—H⋯N hydrogen bonds. As the carboxylic acid group is almost normal to the plane through the benzene ring to which it is attached [C—C—C—C = 93.7 (3) °], and the 4-pyridinealdazine molecule is planar (r.m.s. deviation of the 16 non-H atoms = 0.010 Å), the overall shape of the aggregate is that of an extended chair. In the crystal packing, layers of three component aggregates stack along the c axis.

2-Phenyl­acetic acid–3-{(E)-2-[(E)-pyridin-3-yl­methyl­idene]hydrazin-1-ylidenemeth­yl}pyridine (2/1)

The asymmetric unit of the title 1:2 adduct, C12H10N4·2C8H8O2, comprises a single molecule of 2-phenylacetic acid and half a molecule of 3-pyridinealdazine; the latter is completed by crystallographic inversion symmetry. In the crystal, molecules are connected into a three-component aggregate via O—H⋯N hydrogen bonds. As the carboxyl group lies above the plane through the benzene ring to which it is attached [C—C—C—C = 62.24 (17)°] and the 4-pyridinealdazine molecule is almost planar (r.m.s. deviation of the 16 non-H atoms = 0.027 Å), the overall shape of the aggregate is that of a flattened extended chair. Layers of these aggregates are connected by C—H⋯O and C—H⋯π interactions and stack parallel to (220).