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2-Amino-5-bromopyridinium 3-carboxyprop-2-enoate
Madhukar Hemamalini,Hoong-Kun Fun
Acta Crystallographica Section E , 2010, DOI: 10.1107/s1600536810030059
Abstract: In the title salt, C5H6BrN2+·C4H3O4 , the 2-amino-5-bromopyridinium cation and hydrogen maleate anion are planar, with maximum deviations from their mean planes of 0.016 (1) and 0.039 (1) , respectively. An intramolecular O—H...O hydrogen bond generates an S(7) ring motif in the anion. In the crystal, the protonated N atom and the 2-amino group of the cation are hydrogen-bonded to the carboxylate O atoms of the anion via a pair of N—H...O hydrogen bonds, forming an R22(8) ring motif. The motifs are linked into a two-dimensional network parallel to (011) by N—H...O and C—H...O hydrogen bonds.
2-Amino-4-methylpyridinium (E)-3-carboxyprop-2-enoate  [cached]
Madhukar Hemamalini,Hoong-Kun Fun
Acta Crystallographica Section E , 2010, DOI: 10.1107/s1600536810026292
Abstract: In the title salt, C6H9N2+·C4H3O4 , the dihedral angle between the pyridine ring and the plane formed by the hydrogen fumarate anion is 85.67 (6)°. Excluding the amino and methyl groups, the atoms of the cation are coplanar, with a maximum deviation of 0.005 (1) . In the crystal structure, the protonated N atom and the 2-amino group of the cation are hydrogen bonded to the carboxylate O atoms of the anion via a pair of N—H...O hydrogen bonds, forming an R22(8) ring motif. These motifs are further connected through N—H...O and C—H...O hydrogen bonds, leading to a supramolecular chain along the c axis. These chains are further cross-linked via a pair of O—H...O hydrogen bonds involving centrosymmetrically related hydrogen fumarate anions, forming a two-dimensional network parallel to (101). These planes are further interconnected by O—H...O interactions into a three-dimensional network.
2-Amino-5-chloropyridinium (Z)-3-carboxyprop-2-enoate 0.25-hydrate  [cached]
Madhukar Hemamalini,Hoong-Kun Fun
Acta Crystallographica Section E , 2010, DOI: 10.1107/s1600536810033507
Abstract: In the title hydrated salt, C5H6ClN2+·C4H3O4 ·0.25H2O, the water O atom lies on a twofold axis with half occupancy. The 2-amino-5-chloropyridinium cation is almost planar, with a maximum deviation of 0.015 (3) . In the hydrogen malate anion, an intramolecular O—H...O hydrogen bond generates an S(7) ring and results in a folded conformation. In the crystal, the protonated N atom and the 2-amino group of the cation are hydrogen bonded to the carboxylate O atoms of the anion via a pair of N—H...O hydrogen bonds, forming an R22(8) ring motif. The ion pairs are further connected via O—H...O, N—H...O and C—H...O hydrogen bonds, forming layers parallel to the ab plane which stack down the c axis.
1-(2-Hydroxyethyl)-4-[3-(2-trifluoromethyl-9H-thioxanthen-9-ylidene)propyl]piperazine-1,4-diium dichloride: the dihydrochloride salt of flupentixol
M. S. Siddegowda,Ray J. Butcher,Mehmet Akkurt,H. S. Yathirajan
Acta Crystallographica Section E , 2011, DOI: 10.1107/s1600536811028182
Abstract: In the title compound, C23H27F3N2OS+·2Cl , the piperazinediium ring adopts a chair conformation. The dihedral angle between the two outer aromatic rings of the 9H-thioxanthene unit is 40.35 (18)°. The F atoms in the trifluoromethyl group are disordered over two sets of sites with occupancies of 0.803 (6) and 0.197 (6). In the crystal, molecules are connected by N—H...Cl, O—H...Cl C—H...O and C—H...Cl hydrogen bonds, forming chains propagating along [001]. There are also C—H...π interactions present in the crystal structure.
4-Chloroanilinium 3-carboxyprop-2-enoate  [cached]
R. Anitha,S. Athimoolam,S. Asath Bahadur,M. Gunasekaran
Acta Crystallographica Section E , 2012, DOI: 10.1107/s1600536812008458
Abstract: In the title compound, C6H7ClN+·C4H3O4 , the cations and anions lie on mirror planes and hence only half of the molecules are present in the asymmeric unit. The 4-chloroanilinium cation and hydrogen maleate anion in the asymmetric unit are each planar and are oriented at an angle of 15.6 (1)° to one another and perpendicular to the b axis. A characterestic intramolecular O—H...O hydrogen bond, forming an S(7) motif, is observed in the maleate anion. In the crystal, the cations and anions are linked by N—H...O hydrogen bonds, forming layers in the ab plane. The aromatic rings of the cations are sandwiched between hydrogen-bonded chains and rings formed through the amine group of the cation and maleate anions, leading to alternate hydrophobic (z = 0 or 1) and hydrophilic layers (z = 1/2) along the c axis.
Diaqua[N,N′-bis(3-carboxyprop-2-enoyl)pyridine-2,6-dicarbohydrazidato(2–)]cadmium(II) N,N-dimethylformamide disolvate
Quanfu Cao,Dacheng Li
Acta Crystallographica Section E , 2009, DOI: 10.1107/s1600536809011003
Abstract: In the title complex, [Cd(C15H11N5O8)(H2O)2]·2C3H7NO, the CdII ion is located on a twofold rotation axis and is seven-coordinated in a distorted pentagonal-bipyramidal manner. The asymmetric unit comprises one metal ion, one doubly deprotonated N,N′-bis(3-carboxyprop-2-enoyl)pyridine-2,6-dicarbohydrazide ligand, two coordinating water molecules and two dimethylformamide solvent molecules. In the crystal, a two-dimensional network is formed through N—H...O and O—H...O hydrogen bonds.
Three-dimensional network in piperazine-1,4-diium–picrate–piperazine (1/2/1)  [cached]
Zhong-Long Wang,Li-Hui Jia
Acta Crystallographica Section E , 2008, DOI: 10.1107/s1600536808005710
Abstract: In the title compound, C4H12N22+·2C6H2N3O7 ·C4H10N2, the piperazine-1,4-diium cations and piperazine molecules lie on crystallographic inversion centres. In the crystal structure, intermolecular N—H...O and N—H...N hydrogen bonds link the components to form two-dimensional layers parallel to the (001) plane. These layers are, in turn, connected by weak intermolecular C—H...O hydrogen bonds and π–π stacking interactions [centroid–centroid distance between parallel aryl rings = 3.764 (2) , interplanar spacing = 3.500 (2) and ring offset = 1.387 (2) ], forming a three-dimensional framework.
Piperazine-1,4-diium bis(2-carboxy-1H-pyrazole-4-carboxylate) tetrahydrate  [cached]
Xin-Hui Zhou
Acta Crystallographica Section E , 2010, DOI: 10.1107/s160053681003655x
Abstract: The asymmetric unit of the title compound, C4H12N22+·2C5H3N2O4 ·4H2O, comprises one-half of a piperazine-1,4-diium cation, which lies on an inversion centre, a 2-carboxy-1H-pyrazole-4-carboxylate anion and two water molecules. An extensive network of intermolecular O—H...O, N—H...O, N—H...N and C—H...O hydrogen bonds between the cations, anions and water molecules leads to a three-dimensional supramolecular framework.
Bis[(2S,4S)-4-(2-hydroxyethyl)-2-methylpiperazine-1,4-diium] di-μ-chlorido-bis[trichloridocadmium(II)]  [cached]
Tao Rong
Acta Crystallographica Section E , 2011, DOI: 10.1107/s1600536811006945
Abstract: The asymmetric unit of the title compound, (C7H18N2O)2[Cd2Cl8], comprises one 4-(2-hydroxyethyl)-2-methylpiperazine-1,4-diium dication and a half [Cd2Cl8]4 anion. The two Cd atoms are each coordinated by two bridging Cl atoms and three terminal Cl atoms and the [Cd2Cl8]4 anion is located on an inversion centre. The crystal structure consists of N—H...Cl hydrogen-bonded sheets, which are further linked by C—H...Cl contacts, yielding a three-dimensional network.
(2S,4′R,5′R)-(E)-tert-Butyl 2-acetyl-2-(2-oxo-5-phenyl-1,3-dioxolan-4-ylmethyl)-5-phenylpent-4-enoate
David J. Fox,Daniel Sejer Pedersen,Stuart Warren
Acta Crystallographica Section E , 2008, DOI: 10.1107/s1600536808002651
Abstract: The title compound, C27H30O6, was prepared by monodihydroxylation of the bis-olefin (E,E)-tert-butyl 2-acetyl-2-cinnamyl-5-phenylpent-4-enoate using standard Sharpless asymmetric dihydroxylation conditions, followed by treatment with 1,1′-carbonyl diimidazole. In the crystal structure, the phenyl rings form an intramolecular edge-to-face C—H...π contact with an interplanar angle of 56.4° and a H...centroid distance of 3.03 .
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