Showing papers in "Acta Crystallographica Section E-structure Reports Online in 2009"
TL;DR: Crystals of the title compound, C6H5C2H4NH3)2[PbBr4]n, were grown at room temperature from a solution in N,N-dimethylformamide (DMF) using nitromethane as the poor solvent.
Abstract: Crystals of the title compound, {(C6H5C2H4NH3)2[PbBr4]}n, were grown at room temperature from a solution in N,N-dimethylformamide (DMF) using nitromethane as the poor solvent. This perovskite-type organic–inorganic hybrid compound consists of well ordered sheets of corner-sharing disordered PbBr6 octahedra separated by bilayers of phenethylammonium cations. The octahedra are rotated and tilted due to N—H⋯Br hydrogen bonds with the ammonium groups, generating a superstructure in the unit cell similar to that of the tetrachloridoplumbate (C6H5C2H4NH3)2[PbCl4].
39 citations
TL;DR: In the crystal structure of the title compound, C13H11NO3S, the conformation of the N—H bond in the C—SO2—NH—C(O)—C segment is anti to the C=O bond.
Abstract: In the crystal structure of the title compound, C13H11NO3S, the conformation of the N—H bond in the C—SO2—NH—C(O)—C segment is anti to the C=O bond. The molecule is twisted at theN atom with a dihedral angle of 86.5(1)° between the sulfonyl benzene ring and the —SO2—NH—C=O segment. Furthermore, the dihedral angle between the two benzene rings is 80.3(1)°. The crystal structure features inversion-related dimers linked by pairs of N—H⋯O(S) hydrogen bonds.
28 citations
TL;DR: The NiII complex [Ni(C7H4ClO2) 2(C6H6N2O)2(H2O 2 ) is centrosymmetric with the Ni atom located on an inversion center as mentioned in this paper, and it contains two 2-chloro-benzoate (CB) and two nicotinamide (NA) ligands and two water molecules.
Abstract: The title NiII complex, [Ni(C7H4ClO2)2(C6H6N2O)2(H2O)2], is centrosymmetric with the Ni atom located on an inversion centre. The molecule contains two 2-chlorobenzoate (CB) and two nicotinamide (NA) ligands and two water molecules, all ligands being monodentate. The four O atoms in the equatorial plane around the Ni atom form a slightly distorted square-planar arrangement, while the slightly distorted octahedral coordination is completed by the two N atoms of the NA ligands in the axial positions. The dihedral angle between the carboxyl group and the adjacent benzene ring is 29.48 (16)°, while the pyridine and benzene rings are oriented at a dihedral angle of 83.16 (5)°. In the crystal structure, O—H⋯O and N—H⋯O hydrogen bonds link the molecules into infinite chains. π–π Contacts between the benzene and pyridine rings [centroid–centroid distance = 3.952 (1) A] may further stabilize the crystal structure. There is also a C—H⋯π interaction.
28 citations
TL;DR: The NiII complex as mentioned in this paper is centrosymmetric and contains two 2-bromo-benzoate (BB) ligands, two nicotinamide ligands and two water molecules, all of them being monodentate.
Abstract: The title NiII complex, [Ni(C7H4BrO2)2(C6H6N2O)2(H2O)2], is centrosymmetric. It contains two 2-bromobenzoate (BB) ligands, two nicotinamide (NA) ligands and two water molecules, all of them being monodentate. The four O atoms in the equatorial plane around the Ni atom form a slightly distorted square-planar arrangement, while the slightly distorted octahedral coordination is completed by the two N atoms of the NA ligands in the axial positions. The dihedral angle between the carboxylate group and the adjacent benzene ring is 30.81 (17)°, while the pyridine and benzene rings are oriented at a dihedral angle of 84.66 (6)°. In the crystal structure, O—H⋯O and N—H⋯O hydrogen bonds link the molecules into a supramolecular structure. A weak C—H⋯π interaction is also found.
28 citations
TL;DR: The Schiff base of C15H14N2O4·H2O is almost planar and adopts a trans configuration with respect to the C=N double bond as mentioned in this paper.
Abstract: The Schiff base molecule of the title compound, C15H14N2O4·H2O, adopts a trans configuration with respect to the C=N double bond; the Schiff base itself is almost planar (r.m.s. deviation for all non-H atoms = 0.040 A). The amido N atom is the hydrogen-bond donor to the water molecule, which is the hydrogen-bond donor to the hydroxy groups of two neighboring molecules. One of the hydroxyl groups acts as an intramolecular and the other as an intermolecular hydrogen-bond donor.
25 citations
TL;DR: In the title compound, C14H12ClN3OS, the short exocyclic N—C bond lengths indicate resonance in the thiourea part of the molecule, which results in the formation of a six-membered ring.
Abstract: In the title compound, C14H12ClN3OS, the short exocyclic N—C bond lengths indicate resonance in the thiourea part of the molecule. The title compound is stabilized by an intramolecular N—H⋯N hydrogen bond, which results in the formation of a six-membered ring. In addition, it shows a synperiplanar conformation between the thiocarbonyl group and the pyridine group. Intermolecular N—H⋯S and C—H⋯O interactions are also present.
25 citations
TL;DR: The title compound is a monomeric complex with the MnII atom lying on an inversion center that contains two 4-chlorobenzoate and two diethylnicotinamide ligands and two water molecules, all of which are monodentate.
Abstract: The title compound, [Mn(C7H4ClO2)2(C10H14N2O)2(H2O)2], is a monomeric complex with the MnII atom lying on an inversion center. It contains two 4-chlorobenzoate and two diethylnicotinamide ligands and two water molecules, all of which are monodentate. The four O atoms in the equatorial plane around the Mn atom form a slightly distorted square-planar arrangement, while the distorted octahedral geometry is completed by two N atoms in the axial positions. In the crystal structure, O—H⋯O hydrogen bonds link the molecules into an infinite chain.
23 citations
TL;DR: The complete compound ZnI2(C12H12N2) is generated by crystallograpic twofold symmetry, with the ZnII atom lying on the rotation axis as discussed by the authors.
Abstract: The complete molecule of the title compound, [ZnI2(C12H12N2)], is generated by crystallograpic twofold symmetry, with the ZnII atom lying on the rotation axis. The ZnII atom is coordinated by the N,N-bidentate 6,6′-dimethyl-2,2′-bipyridine ligand and two iodide ions, resulting in a distorted ZnN2I2 tetrahedral geometry for the metal. In the crystal, there are weak π–π contacts between the pyridine rings [centroid–centroid distance = 3.978 (3) A].
19 citations
TL;DR: In the title complex, [Ni(C23H28N2O4)]·H2O, the NiII ion is coordinated by the N2O2 unit of the tetradentate Schiff base ligand in a slightly distorted planar geometry in which the dihedral angle between the two benzene rings is 31.43 (5)°.
Abstract: In the title complex, [Ni(C23H28N2O4)]·H2O, the NiII ion is coordinated by the N2O2 unit of the tetradentate Schiff base ligand in a slightly distorted planar geometry. The asymmetric unit of the title compound comprises one complex molecule and a water molecule of crystallization. The H atoms of the water molecule make bifurcated intermolecular hydrogen bonds with the O atoms of the phenolate and ethoxy groups with R12(5) and R12(6) ring motifs, which may, in part, influence the molecular configuration. The dihedral angle between the two benzene rings is 31.43 (5)°. The crystal structure is further stabilized by intermolecular C—H⋯O and C—H⋯π interactions, which link neighbouring molecules into one-dimensional extended chains along the a axis. An interesting feature of the crystal structure is the short intermolecular C⋯C [3.3044 (14) A] contact which is shorter than the sum of the van der Waals radii.
19 citations
TL;DR: In the title ZnII complex, [Zn(C8H8NO2)2(C6H6N2O)2]·H2O, the Zn atom is coordinated by two 4-methylaminobenzoate (MAB) and two isonicotinamide (INA) ligands in a distorted trigonal-bipyramidal geometry.
Abstract: In the title ZnII complex, [Zn(C8H8NO2)2(C6H6N2O)2]·H2O, the Zn atom is coordinated by two 4-methylaminobenzoate (MAB) and two isonicotinamide (INA) ligands in a distorted trigonal-bipyramidal geometry; one of the MAB ions acts as a bidentate ligand while the other MAB and the two INA are monodentate ligands. The dihedral angles between the carboxyl groups and the adjacent benzene rings are 8.52 (22) and 5.10 (14)°. In the crystal, intermolecular O—H⋯O and N—H⋯O hydrogen bonding links the molecules into a supramolecular structure. Weak intermolecular C—H⋯O interactions are also present.
19 citations
TL;DR: Crystals of the title compound (DBTTF), C14H8S4, feature a triclinic polymorph different from two known monoclinicmorphs, and there are two independent centrosymmetric half-molecules in the asymmetric unit.
Abstract: Crystals of the title compound (DBTTF), C14H8S4, feature a triclinic polymorph different from two known monoclinic polymorphs. In this form, there are two independent centrosymmetric half-molecules in the asymmetric unit. Although the molecular orientations are relatively similar to one of monoclinic polymorphs, the packing motif is different.
TL;DR: The crystal structure of tetrasodium diiron tris(phosphate), Na4Fe2+Fe3+(PO4)3, which has been synthesized hydrothermally at 773 K and 0.1 GPa and is identical to that of γ-NASICON.
Abstract: This paper reports the crystal structure of tetrasodium diiron tris(phosphate), Na4Fe2+Fe3+(PO4)3, which has been synthesized hydrothermally at 773 K and 0.1 GPa. The crystal structure has been refined in the space group R\overline{3}c and is identical to that of γ-NASICON. The heteropolyhedral framework is based on a regular alternation, in three dimensions, of corner-sharing PO4 tetrahedra and FeO6 octahedra, constituting so-called `lantern units' stacked along the c axis. The Na+ cations are distributed over two crystallographic sites: the six-coordinated Na1 site which lies between two `lantern units', and the eight-coordinated Na2 site which lies at the same z value as the P site.
TL;DR: The reaction of Zn(NO3)2 with pyridine-2,6-dicarboxylic acid and acridine in aqueous solution leads to the formation of the title compound, (C13H10N), where the ZnII atom is coordinated by four O atoms and two N atoms from the tridentate chelating rings of ( pydc)2− and (pydcH)− anions.
Abstract: The reaction of Zn(NO3)2 with pyridine-2,6-dicarboxylic acid (pydcH2) and acridine (acr) in aqueous solution leads to the formation of the title compound, (C13H10N)[Zn(C7H3NO4)(C7H4NO4)]·5H2O or (acrH)[Zn(pydcH)(pydc)]·5H2O. In the title compound, the ZnII atom is coordinated by four O atoms and two N atoms from the tridentate chelating rings of (pydc)2− and (pydcH)− anions. The geometry of the resulting ZnN2O4 coordination can be described as distorted octahedral. To balance the charges, one protonated acridine (acrH)+ cation is present. In the crystal structure, extensive O—H⋯O and N—H⋯O hydrogen bonds involving acrH+, the complex anion and uncoordinated water molecules form a three-dimensional network.
TL;DR: In the cystal structure of the title compound, (2-hydroxyethyl)trimethylammonium dihydrogen phosphate, C5H14NO+·H2PO4 −, two anions create dimeric structures via two O—H⋯O hydrogen bonds.
Abstract: In the cystal structure of the title compound, (2-hydroxyethyl)trimethylammonium dihydrogen phosphate, C5H14NO+·H2PO4−, two anions create dimeric structures via two O—H⋯O hydrogen bonds. The hydrogen-bonded dimers are connected by another O—H⋯O hydrogen bond with the hydroxyl groups of the cations, constructing a columner structure along the a axis. A number of C—H⋯O interactions are also present.
TL;DR: In the title compound [systematic name 5-deoxy-5-fluoro-N-(pentyloxycarbonyl)cytidine], C15H22FN3O6, the pentyl chain is disordered over two positions with refined occupancies of 0.53”(5) and 0.47 (5).
Abstract: In the title compound [systematic name 5-deoxy-5-fluoro-N-(pentyloxycarbonyl)cytidine], C15H22FN3O6, the pentyl chain is disordered over two positions with refined occupancies of 0.53 (5) and 0.47 (5). The furan ring assumes an envelope conformation. In the crystal, intermolecular N—H⋯O hydrogen bonds link the molecules into chains propagating along the b axis. The crystal packing exhibits electrostatic interactions between the 5-fluoropyrimidin-2(1H)-one fragments of neighbouring molecules as indicated by short O⋯C [2.875 (3) and 2.961 (3) A] and F⋯C [2.886 (3) A] contacts.
TL;DR: In the tetranuclear centrosymmetric title compound, [Pb4(NO3)8(C11H10N2)4], irregular PbN2O5 and Pbn2O4 coordination polyhedra occur.
Abstract: In the tetranuclear centrosymmetric title compound, [Pb4(NO3)8(C11H10N2)4], irregular PbN2O5 and PbN2O4 coordination polyhedra occur. The heptacoordinated lead(II) ion is bonded to two bidentate and one monodentate nitrate ion and one bidentate 6-methyl-2,2′-bipyridine (mbpy) ligand. The six-coordinate lead(II) ion is bonded to one bidentate and two monodentate nitrate anions and one mbpy ligand. In the crystal, bridging nitrate anions lead to infinite chains propagating in [111]. A number of C—H⋯O hydrogen bonds may stabilize the structure.
TL;DR: In the title compound, C16H16N2O3, the benzohydrazide group is not planar and the molecule exists in a trans configuration with respect to the methylidene unit, where the dihedral angle between the two substituted benzene rings is 26.9 (2)°.
Abstract: In the title compound, C16H16N2O3, the benzohydrazide group is not planar and the molecule exists in a trans configuration with respect to the methylidene unit The dihedral angle between the two substituted benzene rings is 269 (2)° In the crystal structure, the molecular packing is stabilized by intramolecular O—H⋯N and intermolecular N—H⋯O hydrogen bonds The intermolecular hydrogen bonding forms chains parallel to the b axis
TL;DR: The CoII complex as discussed by the authors contains two 4-dimethyl-amino-benzoate (DMAB) anions, one isonicotinamide (INA) ligand and two coordinated water mol-ecules.
Abstract: The title CoII complex, [Co(C9H10NO2)2(C6H6N2O)(H2O)2], contains two 4-dimethylaminobenzoate (DMAB) anions, one isonicotinamide (INA) ligand and two coordinated water molecules. One of the DMAB anions acts as a bidentate ligand, while the other is monodentate. The four O atoms in the equatorial plane around the Co atom form a highly distorted square-planar arrangement, while the distorted octahedral coordination geometry is completed by the N atom of the INA ligand and the O atom of the second water molecule in the axial positions. An intramolecular O—H⋯O hydrogen bond between the monodentate-coordinated carboxyl group and a coordinated water molecule results in a six-membered ring with an envelope conformation. The dihedral angles between the carboxyl groups and the adjacent benzene rings are 4.29 (10)° for the monodentate ligand and 2.31 (13)° for the bidentate ligand, while the two benzene rings are oriented at a dihedral angle of 65.02 (5)°. The dihedral angles between the pyridine and benzene rings are 11.21 (5)° for the monodentate ligand and 74.60 (5)° for the bidentate ligand. In the crystal structure, intermolecular O—H⋯O, O—H⋯N and N—H⋯O hydrogen bonds link the molecules into a supramolecular structure.
TL;DR: The title compound, C16H17NO, is a Schiff base which adopts the phenol–imine tautomeric form in the solid state and is stabilized by an intramolecular O—H⋯N hydrogen bond which generates a six membered ring.
Abstract: The title compound, C16H17NO, is a Schiff base which adopts the phenol–imine tautomeric form in the solid state. The molecule is almost planar, with a dihedral angle of 4.61 (4)° between the aromatic rings. The molecular structure is stabilized by an intramolecular O—H⋯N hydrogen bond which generates a six membered ring.
TL;DR: The MnII complex as discussed by the authors contains two 4-(dimethylamino)benzoate (DMAB) anions, one isonicotinamide (INA) ligand and two coordinated water mol-ecules.
Abstract: The title MnII complex, [Mn(C9H10NO2)2(C6H6N2O)(H2O)2], contains two 4-(dimethylamino)benzoate (DMAB) anions, one isonicotinamide (INA) ligand and two coordinated water molecules. One of the DMAB anions acts as a bidentate ligand, while the other is monodentate. The four O atoms in the equatorial plane around the Mn atom form a highly distorted square-planar arrangement, while the distorted octahedral coordination geometry is completed by the N atom of the INA ligand and the O atom of the second water molecule in the axial positions. In the crystal structure, strong intermolecular O—H⋯O, O—H⋯N and N—H⋯O hydrogen bonds link the molecules into a two-dimensional network parallel to (010). Two weak C—H⋯π interactions are also found.
TL;DR: The asymmetric unit of the title Cd(II) complex contains two 4-formyl-benzoate (FB), two isonicotinamide (INA) ligands, one coordinated and one uncoordinated water mol-ecule; the FB ions act as bidentate ligands.
Abstract: The asymmetric unit of the title CdII complex, [Cd(C8H5O3)2(C6H6N2O)2(H2O)]·H2O, contains two 4-formylbenzoate (FB), two isonicotinamide (INA) ligands, one coordinated and one uncoordinated water molecule; the FB ions act as bidentate ligands The coordination number of the Cd(II) atom is seven within a CdO5N2 donor set Intramolecular O—H⋯O hydrogen bonds link the uncoordinated water molecules to the carboxyl groups The dihedral angle between the carboxylate groups and the adjacent benzene rings are 1753 (13) and 1655 (14)° In the crystal structure, intermolecular O—H⋯O, N—H⋯O, N—H⋯N and C—H⋯O hydrogen bonds link the molecules into a supramolecular structure The amide group of one of the INA ligands is disordered over two orientations, with an occupancy ratio of 0759 (3):0241 (3)
TL;DR: In the title complex, [Ni(C21H24N2O4)]·1.78H2O, the NiII ion has a slightly distorted planar geometry, coordinated by the two N and two O atoms of the tetradentate Schiff base ligand, with a mean deviation of 0.272 Å from the NiN2 O2 plane.
Abstract: In the title complex, [Ni(C21H24N2O4)]·1.78H2O, the NiII ion has a slightly distorted planar geometry, coordinated by the two N and two O atoms of the tetradentate Schiff base ligand, with a mean deviation of 0.272 A from the NiN2O2 plane. The N and O donor atoms are mutually cis. The dihedral angle between two benzene rings of the ligand is 38.86 (8)°. There are also three solvent water molecules, two of which lie across different crystallographic twofold rotation axes; one of these is partially occupied with a refined occupancy factor of 0.570 (7). The water molecules are linked together as tetramers in R22(8) ring motifs, which also connect two neighbouring molecules of the complex through a network of O—H⋯O hydrogen bonds. The crystal structure is further stabilized by intermolecular C—H⋯O and C—H⋯π interactions, which link neighbouring molecules into extended chains along the b axis. Other interesting features of the crystal structure are the short intermolecular C⋯C [3.204 (3)–3.365 (3) A] and the C⋯O [3.199 (2)–3.205 (2) A] contacts which are shorter than the sum of the van der Waals radii of these atoms.
TL;DR: In the monomeric title complex, the MnII atom is located on a crystallographic centre of inversion, the asymmetric unit contains one 2-chlorobenzoate ligand, one diethylnicotinamide (DENA) ligand and one coordinated water molecule, all ligands being monodentate.
Abstract: In the monomeric title complex, [Mn(C7H4ClO2)2(C10H14N2O)2(H2O)2], the MnII atom is located on a crystallographic centre of inversion. The asymmetric unit contains one 2-chlorobenzoate (CB) ligand, one diethylnicotinamide (DENA) ligand and one coordinated water molecule, all ligands being monodentate. The four O atoms in the equatorial plane around the Mn atom form a slightly distorted square-planar arrangement, while the slightly distorted octahedral coordination is completed by the two pyridine N atoms of the DENA ligands in the axial positions. The dihedral angle between the carboxyl group and the adjacent benzene ring is 77.9 (11)°, while the pyridine and benzene rings are oriented at a dihedral angle of 45.94 (5)°. In the crystal structure, intermolecular O—H⋯O hydrogen bonds link the molecules into infinite chains.
TL;DR: In the molecule of the title compound, [HgBr2(C14H12N2)], the HgII atom is four-coordinated in a distorted tetrahedral configuration by two N atoms from a 2,9-dimethyl-1,10-phenanthroline ligand and by two Br atoms.
Abstract: In the molecule of the title compound, [HgBr2(C14H12N2)], the HgII atom is four-coordinated in a distorted tetrahedral configuration by two N atoms from a 2,9-dimethyl-1,10-phenanthroline ligand and by two Br atoms. In the crystal structure, weak intermolecular C—H⋯Br hydrogen bonds link the molecules into chains along the b axis. There are π–π contacts between the phenanthroline rings [centroid–centroid distances = 3.806 (4), 3.819 (4), 3.739 (3), 3.690 (3), 3.619 (4) and 3.674 (3) A].
TL;DR: Crystals of the title compound, C57H85N9O9·CH4O, the methanol solvate of a nine peptide polypeptide, cyclo-(Pro-Pro- Phe-Phe-Leu-Ile-I Le-Lei-Val), were obtained after separation of the cyclic peptide from flax oil.
Abstract: Crystals of the title compound, C57H85N9O9·CH4O, the methanol solvate of a nine peptide polypeptide, cyclo-(Pro-Pro-Phe-Phe-Leu-Ile-Ile-Leu-Val), were obtained after separation of the cyclic peptide from flax oil. The cyclolinopeptide A (CLP-A) molecules are linked in chains along the a axis by N—H⋯O hydrogen bonds. Each methanol O atom is hydrogen bonded to one O atom and two N—H groups in the same CLP-A molecule. There are a total of eight hydrogen bonds in each CLP-A–MeOH unit.
TL;DR: The molecule of the title heteroaryl chalcone, C16H16O4S, which consists of substituted thiophene and benzene rings bridged by the prop-2-en-1-one group, is slightly twisted.
Abstract: The molecule of the title heteroaryl chalcone, C16H16O4S, which consists of substituted thiophene and benzene rings bridged by the prop-2-en-1-one group, is slightly twisted. The dihedral angle between the thiophene and 3,4,5-trimethoxyphenyl rings is 12.18 (4)°. The three methoxy groups have two different conformations; two methoxy groups are coplanar [C—O—C—C torsion angles = −1.38 (12) and 0.47 (12)°] whereas the third is (-)-synclinal with the benzene ring. In the crystal structure, adjacent molecules are linked in a face-to-side manner into chains along the c axis by weak C—H⋯O(enone) interactions. These chains are stacked along the b axis by weak C—H⋯O(methoxy) interactions.
TL;DR: The molecule adopts the enol–imine tautomeric form with an intramolecular hydrogen-bonding interaction between the Schiff base N atom and the hydroxy group, and in the crystal, intermolecular N—H⋯O and O—H–O hydrogen bonds link the molecules into a three-dimensional network.
Abstract: All the non-H atoms of the title compound, C10H10N4O3, are almost coplanar, the maximum deviation from planarity being 0.065 (3) A. The dihedral angle between the aromatic rings is 1.66 (6)°. The molecule adopts the enol–imine tautomeric form with an intramolecular hydrogen-bonding interaction between the Schiff base N atom and the hydroxy group. In the crystal, intermolecular N—H⋯O and O—H⋯O hydrogen bonds link the molecules into a three-dimensional network.
TL;DR: The asymmetric unit in the title compound, C5H5NO, comprises two independent but virtually identical molecules of 2-pyridone, and represents a monoclinic polymorph of the previously reported orthorhombic form.
Abstract: The asymmetric unit in the title compound, C5H5NO, comprises two independent but virtually identical molecules of 2-pyridone, and represents a monoclinic polymorph of the previously reported orthorhombic (P212121) form [Penfold (1953). Acta Cryst. 6, 591–600; Ohms et al. (1984). Z. Kristallogr. 169, 185–200; Yang & Craven (1998). Acta Cryst. B54, 912–920]. The independent molecules are linked into supramolecular dimers via eight-membered {⋯HNC(O)}2 amide synthons in contrast to the helical supramolecular chains, mediated by {⋯HNC(O)} links, found in the orthorhombic form.
TL;DR: The Ir centre in the title complex, [Ir(C11H6F2N)2(C6H4NO2)], is six-coordinated in a slightly distorted octahedral IrC2N3O fashion.
Abstract: The Ir centre in the title complex, [Ir(C11H6F2N)2(C6H4NO2)], is six-coordinated in a slightly distorted octahedral IrC2N3O fashion.
TL;DR: The title organic salt was synthesized from cytosine base and maleic acid, giving rise to a nearly planar two-dimensional network parallel to (101), and an intramolecular O—H⋯O hydrogen bond occurs in the hydrogen maleate anion.
Abstract: The title organic salt, C4H6N3O+·C4H3O4−·C4H5N3O, was synthesized from cytosine base and maleic acid. An intramolecular O—H⋯O hydrogen bond occurs in the hydrogen maleate anion. The crystal packing is stabilized by intermolecular N—H⋯O, N—H⋯N and C—H⋯O hydrogen bonds, giving rise to a nearly planar two-dimensional network parallel to (101).