83) Rietveld refinement of the cocrystal 2,4-dihydroxybenzoic acid–N-(propan-2-ylidene)nicotinohydrazide (1/1) (original) (raw)
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Journal of Molecular Structure, 2018
Four novel cocrystals of the anti-tuberculosis drug Isoniazid (INH), including two polymorphs, with the aromatic carboxylic acids p-nitrobenzoic (PNBA), p-cyanobenzoic (PCNBA) and p-aminobenzoic (PABA) were rationally designed and synthesized by solvent evaporation. Aiming to explore the possible supramolecular synthons of this API, these cocrystals were fully characterized by X-ray diffraction (SCXRD, PXRD), spectroscopic (FT-IR) and thermal (TGA, DSC, HSM) techniques. The cocrystal formation was found to be mainly driven by the synthons formed by the pyridine and hydrazide moieties. In both INH−PABA polymorphs, the COOH acid groups are H-bonded to pyridine and hydrazide groups giving rise to the acid•••pyridine and acid•••hydrazide heterosynthons. In INH−PNBA and INH−PCNBA cocrystals these acid groups are only related to the pyridine moiety. In addition to the structural study, supramolecular and Hirshfeld surface analysis were also performed based on the structural data. The cocrystals were identified from the FT-IR spectra and their thermal behaviors were studied by a combination of DSC, TGA and HSM techniques.
Acetazolamide (ACZ) has been combined via liquid-assisted grinding in water with a library of cocrystal formers derived from benzoic and nicotinic acid, which provided novel cocrystals with 2-hydroxybenzamide, 2aminobenzamide, picolinamide, and 2,3-dihydroxybenzoic acid. The cocrystalline phases were identified first by XRPD analysis and then structurally characterized by IR spectroscopy and single-crystal X-ray diffraction analysis. These cocrystals and the previously reported cocrystalline phases obtained from 4-hydroxybenzoic acid and nicotinamide constitute a series of six cocrystals of varied stoichiometric ratios (3:1, 2:1, 1:1, and 1:2), which allowed for a profound analysis of the structural and chemical factors that govern their formation. The structural analysis has shown that the ACZ molecules participate in the dominant hydrogen-bonding patterns within the crystal structures: three cocrystal structures exhibit extended supramolecular aggregates of ACZ having channels, pores, or semispherical voids, in which the cocrystal formers are included as guest molecules, and can, therefore, be described as inclusion or clathrate complexes. One cocrystal can be considered as a pillared or intercalation compound, and the remaining two cocrystals are true two-component 2D or 3D networks. In addition, a variety of alternative preparative methods (liquidassisted grinding, neat grinding, reaction crystallization, solution-mediated phase transformation, and solution crystallization) have been employed, showing that four of the six cocrystals required the presence of water for successful cocrystal formation.
Crystal structure of a 1:1 cocrystal of nicotinamide with 2-chloro-5-nitrobenzoic acid
Acta Crystallographica Section E Crystallographic Communications, 2019
In the title 1:1 cocrystal, C7H4ClNO4·C6H6N2O, nicotinamide (NIC) and 2-chloro-5-nitrobenzoic acid (CNBA) cocrystallize with one molecule each of NIC and CNBA in the asymmetric unit. In this structure, CNBA and NIC form hydrogen bonds through O—H...N, N—H...O and C—H...O interactions along with N—H...O dimer hydrogen bonds of NIC. Further additional weak π–π interactions stabilize the molecular assembly of this cocrystal.
Acta Crystallographica Section E Crystallographic Communications, 2016
The title 2:1 co-crystal, 2C7H5NO4·C14H14N4O2, in which the complete diamide molecule is generated by crystallographic inversion symmetry, features a three-molecule aggregate sustained by hydroxyl-O—H...N(pyridyl) hydrogen bonds. Thep-nitrobenzoic acid molecule is non-planar, exhibiting twists of both the carboxylic acid and nitro groups, which form dihedral angles of 10.16 (9) and 4.24 (4)°, respectively, with the benzene ring. The diamide molecule has a conformation approximating to a Z shape, with the pyridyl rings lying to either side of the central, almost planar diamide residue (r.m.s. deviation of the eight atoms being 0.025 Å), and forming dihedral angles of 77.22 (6)° with it. In the crystal, three-molecule aggregates are linked into a linear supramolecular ladder sustained by amide-N—H...O(nitro) hydrogen bonds and orientated along [10-4]. The ladders are connected into a double layerviapyridyl- and benzene-C—H...O(amide) interactions, which, in turn, are connected into a ...
Journal of Chemical Crystallography, 2011
The eight-membered {ÁÁÁHOC=O} 2 synthon featured in the crystal structure of 2-amino-4-nitrobenzoic acid (1) is replaced by carboxylic acidÁÁÁN-pyridine hydrogen bonds in its cocrystals with 2,2 0-bipyridine (2/1; 2) and bis(pyridin-2-yl)ketone (1/1; 3) indicating the robust nature of the latter synthon. Disruption of the three-dimensional architecture based on O-HÁÁÁO and N-HÁÁÁO(nitro) hydrogen bonds in (1) is evident in the cocrystals which form supramolecular tubes (2) and chains (3) based on O-HÁÁÁN and N-HÁÁÁO hydrogen bonding. Compound (1) crystallizes in the monoclinic space group P2 1 /n with a = 3.6291(1) Å , b = 7.7339(3) Å , c = 26.561(1) Å , b = 91.385(2)°, and Z = 4. Compound (2) crystallizes in the monoclinic space group C2/c with a = 27.562(3) Å , b = 6.8300(6) Å , c = 12.923(1) Å , b = 110.593(5)°, and Z = 4. Compound (3) crystallizes in the monoclinic space group P2 1 /c with a = 3.795(3) Å , b = 12.024(8) Å , c = 35.65(2) Å , b = 92.131(6)°, and Z = 4 (determined from synchrotron data).
Solid state nuclear magnetic resonance, 2014
We present the structure of a new equimolar 1:1 cocrystal formed by 3,5-dimethyl-1H-pyrazole (dmpz) and 4,5-dimethyl-1H-imidazole (dmim), determined by means of powder X-ray diffraction data combined with solid-state NMR that provided insight into topological details of hydrogen bonding connectivities and weak interactions such as CH···π contacts. The use of various 1D/2D (13)C, (15)N and (1)H high-resolution solid-state NMR techniques provided structural insight on local length scales revealing internuclear proximities and relative orientations between the dmim and dmpz molecular building blocks of the studied cocrystal. Molecular modeling and DFT calculations were also employed to generate meaningful structures. DFT refinement was able to decrease the figure of merit R(F(2)) from ~11% (PXRD only) to 5.4%. An attempt was made to rationalize the role of NH···N and CH···π contacts in stabilizing the reported cocrystal. For this purpose four imidazole derivatives with distinct placeme...
Zeitschrift für Kristallographie - Crystalline Materials, 2018
Crystallography reveals two polymorphs for the salt [4-(4-acetylphenyl)piperazin-1-ium][2-amino-4-nitrobenzoate], a monoclinic form (2; modelled as P21/n with Z′=4) formed directly from the reaction mixture, and a triclinic form (1; Z′=1) isolated from recrystallisation. Relatively minor differences are noted in the conformations of the anions and of the cations, mainly relating to the twist of, respectively, the carboxylate groups and piperazin-1-ium rings with respect to the phenyl rings they are connected to. The key feature of the packing of both forms is the formation of charge-assisted ammonium-N–H···O (carboxylate) hydrogen bonds which lead to cyclic 12-membered {···HNH ···OCO}2 synthons in the case of 1 but, supramolecular chains in 2. The three-dimensional architecture in the crystal of 1 is further stabilised by amine-N–H···O (nitro) and amine-N–H···O (acetyl) hydrogen bonds, leading to double-layers in the bc-plane, which are linked along the a-axis by methylene-C–H···O (...
Supramolecular Structure of Cocrystallized J-Amino Butyric Acid and Oxalic Acid
2011
Pharmaceutical cocrystals are crystalline molecular complexes that contain therapeutically active molecules. In many cases properties important to the bioavailability or processing of pharmaceutical solids have been demonstrated to be improved upon via cocrystallization. The structural elements (strong hydrogen bond donor, strong hydrogen bond acceptor, and nonpolar region) of J-amino butyric acid, GABA, are typical of small drug molecules, and GABA is a major neurotransmitter inhibitor of the central nervous system. GABA and oxalic acid, OX, were cocrystallized as part of a study on formation of cocrystals of pharmaceutically interesting molecules via hydrogen bonding. The crystal structure of the resulting transparent colorless 2GABA:OX cocrystal was studied by single crystal X-ray analysis (monoclinic; P2 1 /c; a = 7.4153(9), b = 10.2052(13), c = 9.7584(12) A, E = 108.396(3) R , V
CrystEngComm, 2014
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