N-(4-Chloro­phen­yl)-3-nitro­pyridin-2-amine

In the title compound, C11H8ClN3O2, the presence of intra­molecular N—H⋯O and C—H⋯N inter­actions help to establish an almost planar mol­ecule [dihedral angle between the pyridine and benzene rings = 9.89 (8)° and r.m.s. deviation for all 17 non-H atoms = 0.120 Å]. Supra­molecular tapes feature in the crystal packing whereby dimeric aggregates sustained by pairs of C—H⋯O inter­actions are connected by π–π inter­actions occurring between translationally related pyridine rings and between translationally related benzene rings along the b axis [centroid–centroid distance = length of b axis = 3.8032 (4) Å]

N-(4-Methyl­phen­yl)-3-nitro­pyridin-2-amine1

Two independent mol­ecules comprise the asymmetric unit of the title compound, C12H11N3O2. These differ in terms of the relative orientations of the benzene rings as seen in the respective dihedral angles formed between the pyridine and benzene rings [17.42 (16) and 34.64 (16)°]. Both mol­ecules are twisted about the amine–tolyl N—C bonds [respective torsion angles = 22.3 (5) and 35.9 (5)°] but only about the amine–pyridine N—C bond in the first independent mol­ecule [respective torsion angles = −11.7 (5) and 0.8 (5)°]. Intra­molecular N—H⋯O hydrogen bonds preclude the amine H atoms from forming significant inter­molecular inter­actions. The crystal packing features inter­molecular C—H⋯O and C—H⋯π and π–π [centroid–centroid distance: pyridine–benzene = 3.6442 (19) Å and pyridine–pyridine = 3.722 (2) Å] contacts

N-(4-Chloro­phen­yl)quinolin-2-amine

There is a twist in the title mol­ecule, C15H11ClN2, as seen in the dihedral angle of 18.85 (9)° between the quinoline and benzene rings. A short C—H⋯N contact arises from this conformation and the amine H and quinoline N atoms are directed towards opposite sides of the mol­ecule. In the crystal, supra­molecular layers in the ab plane are mediated by C—H⋯π inter­actions

2-(2-Meth­oxy­phen­oxy)pyrazine

A significant twist is observed in the title molecule, C11H10N2O2, as seen in the dihedral angle between the pyrazine and benzene rings of 72.79 (8)°. The meth­oxy group is almost coplanar with the benzene ring to which it is attached [C—O—C—C torsion angle = 175.83 (15)°]. Centrosymmetric dimers are formed in the crystal structure which are held together by weak π–π inter­actions between pyrazine rings [centroid–centroid distance = 3.8534 (10) Å]

Three ammonium salts of sulfathiazole: crystallography and anti-microbial assay

The crystal and molecular structures of three ammonium salts derived from sulfathiazole are described. In each case, the anion is in the azanide form, features an intramolecular S←O interaction, and adopts a U-shape. The structures of two cations, [R(HOCH2CH2)NH2]+, namely for R = Me (1) and iPr (2), are unprecedented in the crystallographic literature. Extensive hydrogen bonding is observed in all crystal structures and leads to a two-dimensional array for 1, and three-dimensional architectures for each of 2 and 3 (R = CH2CH2OH). The salts exhibited anti-microbial activity against a range of Gram-positive and Gram-negative bacteria, and proved bactericidal toward Vibrio parahaemolyticus, but had no advantage over sulfathiazole itself

Synthesis, characterisation, and crystallographic studies of sulfathiazole salts and related species / Siti Aina Mardia Akhmad Aznan

Co-crystallisation of equimolar quantities of sulfathiazole (STL) with each of 1,4-diazabicyclo[2.2.2]octane (DABCO) and piperazine (PIP) resulted in facile formation of salts [DABCOH][STL_H] (1) and [PIPH][STL_H] (2), respectively. Crystallographic studies show the formation of aniline-N–H...O(sulfonyl) hydrogen bonds between anions to form supramolecular undulating and zigzag layers, respectively, with the cations being connected to these by charge-assisted N–H...N(thioazole) interactions. The salts formations were confirmed by 1H NMR, IR, Raman spectroscopies, CHN elemental analysis, Single Crystal X-ray Diffraction (SCXRD), Powder X-ray Diffraction (PXRD) and Differential Scanning Calorimetry (DSC) as well as melting point. Solid state grinding competition experiments were monitored by PXRD. In a sequence of experiments where STL was co-ground with a molar equivalent of PIP and n equivalents of DABCO (with n increasing from 0.1 to 1.0 in 0.1 increments), formation of salt 1 was observed. In related experiments where salt 2 was ground with an equimolar amount of DABCO, substitution of PIPH+ by DABCOH+ was evident, i.e., postsynthetic metathesis had occurred to about 70% for dry grinding. Quantitative yields were obtained in the case of liquid-assisted grinding (LAG) with a few drops of ethanol after 1.4 equivalents of DABCO were added. These observations are primarily correlated with differences in aniline-N–H...O(sulfonyl) hydrogen bonding that sustain the layers

Crystal structures of 1,4-diazabicyclo[2.2.2]octan-1-ium 4-nitrobenzoate dihydrate and 1,4-diazabicyclo[2.2.2]octane-1,4-diium bis(4-nitrobenzoate): the influence of solvent upon the stoichiometry of the formed salt

The 1:1 co-crystallization of 1,4-diazabicyclo[2.2.2]octane (DABCO) with 4-nitrobenzoic acid in ethanol–water (3/1) gave the salt dihydrate C6H13N2+·C7H4NO4−·2H2O, (1), whereas from methanol, the salt C6H14N22+·2C7H4NO4−, (2), was isolated. In (1), the cation and anion are linked by a strong N—H...O hydrogen bond, and the carboxylate anion is close to planar [dihedral angle between terminal residues = 6.83 (9)°]. In (2), a three-ion aggregate is assembled by two N—H...O hydrogen bonds, and the carboxylate anions are again close to planar [dihedral angles between terminal residues = 1.7 (3) and 5.9 (3)°]. Through the intervention of solvent water molecules, which self-assemble into helical supramolecular chains along the b axis, the three-dimensional architecture in (1) is stabilized by water–DABCO O—H...N and water–carboxylate O—H...O hydrogen bonds, with additional stability afforded by C—H...O interactions. The global crystal structure comprises alternating layers of water molecules and ion pairs stacked along the c axis. In the crystal of (2), the three-ion aggregates are assembled into a three-dimensional architecture by a large number of methylene–carboxylate/nitro C—H...O interactions as well as π–π contacts between inversion-related benzene rings [inter-centroid distances = 3.5644 (16) and 3.6527 (16) Å]. The cations and anions assemble into alternating layers along the c axis

Crystal structure of a new monoclinic polymorph of N-(4-methylphenyl)-3-nitropyridin-2-amine

The title compound, C12H11N3O2, is a second monoclinic polymorph (P21, with Z′ = 4) of the previously reported monoclinic (P21/c, with Z′ = 2) form [Akhmad Aznan et al. (2010). Acta Cryst. E66, o2400]. Four independent molecules comprise the asymmetric unit, which have the common features of a syn disposition of the pyridine N atom and the toluene ring, and an intramolecular amine–nitro N—H...O hydrogen bond. The differences between molecules relate to the dihedral angles between the rings which range from 2.92 (19) to 26.24 (19)°. The geometry-optimized structure [B3LYP level of theory and 6–311 g+(d,p) basis set] has the same features except that the entire molecule is planar. In the crystal, the three-dimensional architecture is consolidated by a combination of C—H...O, C—H...π, nitro-N—O...π and π–π interactions [inter-centroid distances = 3.649 (2)–3.916 (2) Å]

4-Nitrobenzoic acid–N-(pyrimidin-2-yl)aniline (1/1)

Four independent molecules comprise the asymmetric unit of the title co-crystal, C10H9N3·C7H5NO4, two for each component. Small conformational differences are noted for the benzoic acid derivatives, notably in the twists of the carboxylic acid residue out of the plane of the benzene ring to which it is connected [torsion angles = 167.62 (17) and 174.54 (17)°]. In the aniline derivative, the major difference is observed in the dihedral angles formed between the CN3 and phenyl least-squares planes [1.51 (5) and 6.25 (6)°]. Pairs of molecules associate via O—H...N and N—H...O hydrogen bonds leading to eight-membered {...HOCO...HNCN} hetero-synthons. The two-molecule aggregates are consolidated in the crystal structure by C—H...O(nitro) and π–π interactions [shortest centroid–centroid distance between benzene rings = 3.6242 (10) Å]