In the title compound, 2C(5)H(6)BrN(2) (+)·C(4)H(2)O(4) (2-)·2H(2)O, the complete fumarate dianion is generated by crystallographic inversion symmetry. The cation is approximately planar, with a maximum deviation of 0.036 (1) Å. In the anion, the carboxyl-ate group is twisted slightly away from the attached plane; the dihedral angle between carboxyl-ate and (E)-but-2-ene planes is 6.11 (14)°. In the crystal, the carboxyl-ate O atoms form bifurcated (N-H⋯O and C-H⋯O) and N-H⋯O hydrogen bonds with the cations. The crystal packing is stabilized by R(2) (2)(8) ring motifs which are generated by pairs of N-H⋯O hydrogen bonds. The crystal structure is further consolidated by water mol-ecules via O(water)-H⋯O and N-H⋯O(water) hydrogen bonds. The components are linked by these inter-actions into three-dimensional network.
In the title compound, C(9)H(8)NO(+)·C(3)H(3)O(4) (-), the cation and anion are each essentially planar, with maximum deviations of 0.043 (1) and 0.060 (1) Å, respectively. The dihedral angle between these two planes is 2.20 (4)°. The conformation of the anion is stabilized by an intra-molecular O-H⋯O hydrogen bond, which forms an S(6) ring motif. The hy-droxy group of the oxine unit makes a hydrogen bond with the one of the O atoms of the carboxyl-ate group of the 2-carb-oxy-acetate anion. Two other carboxyl-ate O atoms form R(2) (2)(7) ring motifs via inter-molecular C-H⋯O and N-H⋯O hydrogen bonds. The crystal structure is consolidated by weak inter-molecular C-H⋯O inter-actions, which link the cations and anions into a three-dimensional network.
In the title compound, C(6)H(9)N(2) (+)·C(7)H(5)O(3) (-), the protonated 2-amino-5-methyl-pyridinium cation and the 2-hy-droxy-benzoate anion are both essentially planar, with maximum deviations of 0.026 (2) and 0.034 (1) Å, respectively. The anion is stabilized by an intra-molecular O-H⋯O hydrogen bond, which forms an S(6) ring motif. In the solid state, the anions are linked to the cations via pairs of inter-molecular N-H⋯O hydrogen bonds forming R(2) (2)(8) ring motifs. The crystal structure is further stabilized by N-H⋯O and C-H⋯O inter-actions which link the mol-ecules into chains along [010]. A π-π stacking inter-action [centroid-centroid-distance = 3.740 (2) Å] is also observed.
In the title cholestane derivative, C(28)H(48) [systematic name: (1S,2S,7R,10R,11R,14R,15R)-2,5,10,15-tetra-methyl-14-[(2R)-6-methyl-heptan-2-yl]tetra-cyclo-[8.7.0.0(2,7).0(11,15)]hepta-dec-4-ene], the cyclo-hexene ring adopts a half-chair conformation. The parent 5α-cholest-2-ene and the equivalent fragment of the title compound are almost superimposable (r.m.s. deviation = 0.033 Å).
The asymmetric unit of the title compound, C(5)H(6)BrN(2) (+)·C(8)H(5)O(4) (-), consists of two crystallographically independent 2-amino-5-bromo-pyridinium cations (A and B) and two 2-carb-oxy-benzoate anions (A and B). Each 2-amino-5-bromo-pyridinium cation is approximately planar, with a maximum deviation of 0.047 (1) Å in cation A and 0.027 (1) Å in cation B. The 2-amino-5-bromo-pyridinium unit in cation A is inclined at dihedral angles of 4.9 (3) and 2.2 (3)° with the phenyl rings of the A and B 2-carb-oxy-benzoate anions, respectively. The corresponding angles for cation B are 3.0 (3) and 5.6 (3)°. The mol-ecular structure is stabilized by an intra-molecular O-H⋯O hydrogen bond,which generates an S(7) ring motif. The cations and anions are linked via inter-molecular N-H⋯O and C-H⋯O hydrogen bonds, generating R(2) (2)(8) ring motifs. In the crystal packing, mol-ecules are linked into wave-like chains along [001] via adjacent ring motifs. Short inter-molecular distances between the phenyl and pyridine rings [3.613 (4) and 3.641 (4) Å] indicate the existence of π-π inter-actions. The crystal structure is a non-merohedral twin with a contribution of 0.271 (3) of the minor component.
The quinoxaline system in the title hydrate, C(15)H(13)N(3)·H(2)O, is roughly planar, the r.m.s. deviation for the 18 non-H atoms being 0.188 Å; this conformation features a short intra-molecular C-H⋯N(pyrazine) inter-action. In the crystal, the amine H atom forms an N-H⋯O hydrogen bond to the water mol-ecule, which in turn forms two O-H⋯N hydrogen bonds to the pyrazine N atoms of different organic mol-ecules. These inter-actions lead to supra-molecular arrays in the bc plane that are two mol-ecules thick; additional π-π inter-actions stabilize the layers [ring centroid-centroid distance = 3.5923 (7) Å]. The layers stack along the a-axis direction via C-H⋯π contacts.
In the crystal structure of the title compound, C(8)H(9)N(2) (+)·SCN(-)·C(8)H(8)N(2), the three components are linked by inter-molecular N-H⋯N and N-H⋯S hydrogen bonds into infinite chains along the c axis.
In the crystal structure of the title compound, C(4)H(7)N(4)O(+)·Cl(-)·2H(2)O, adjacent cations are connected to one another through N-H⋯O hydrogen bonds, forming infinite chains along the b axis. These chains are further hydrogen bonded to the chloride anions and water mol-ecules, resulting in a three-dimensional network. The pyrimidine rings of adjacent mol-ecules are arranged in an anti-parallel manner above each other with centroid-centroid distances of 3.435 (1) Å, indicative of π-π inter-actions.
In the title compound, C(11)H(10)N(2)O(2), the aromatic rings are almost orthogonal to each other [dihedral angle = 86.97 (8)°], with the benzene ring orientated to face one of the pyrazine N atoms. In the crystal, centrosymmetrically related pairs are connected via pairs of C-H⋯π inter-actions and the dimeric units thus formed pack into undulating layers that stack along the a axis.
The asymmetric unit of the title salt, C(5)H(6)ClN(2) (+)·C(7)H(5)O(6)S(-), contains two independent 2-amino-5-chloro-pyridinium cations and two independent 3-carb-oxy-4-hy-droxy-benzene-sulfonate anions. In both anions, the O atoms of the sulfonate group are disordered over two sets of positions, with occupancy ratios of 0.47 (5):0.53 (5) and 0.50 (8):0.50 (8). In each anion, an intra-molecular O-H⋯O hydrogen bond generating an S(6) motif is observed. In the crystal structure, the cations and anions are linked via N-H⋯O, O-H⋯O and C-H⋯O hydrogen bonds, forming a two-dimensional network parallel to (110). The structure is further stabilized by π-π inter-actions between cations and anions [centroid-centroid distance = 3.5454 (12) Å]. The crystal studied was a non-merohedral twin, with a ratio of the twin components of 0.715 (3):0.285 (3).
In the title salt, C(5)H(6)ClN(2) (+)·C(6)H(4)NO(3) (-)·0.85H(2)O, the pyridin-ium ring is planar, with a maximum deviation of 0.010 (2) Å. In the crystal structure, the cations, anions and water mol-ecules are linked via N-H⋯O, O-H⋯O and C-H⋯O hydrogen bonds, forming a three-dimensional network.
The asymmetric unit of the title compound, C(10)H(6)N(2)·0.5C(4)H(4)O(4), consists of one quinoline-2-carbonitrile mol-ecule and a half-mol-ecule of fumaric acid, which lies on an inversion center. The quinoline-2-carbonitrile mol-ecule is almost planar, with an r.m.s. deviation of 0.008 (1) Å. The acid and base are linked together via pairs of inter-molecular C-H⋯O and O-H⋯N hydrogen bonds, forming R(2) (2)(8) ring motifs. In the crystal, the carbonitrile mol-ecules are further linked by inter-molecular C-H⋯N hydrogen bonds, generating R(2) (2)(10) ring motifs, resulting in zigzag chains running along the c axis.
In the title salt, C(5)H(8)N(3) (+)·C(6)H(7)O(2) (-), the pyridine N atom of the 2,3-diamino-pyridine mol-ecule is protonated. The 2,3-diamino-pyridinium cation is essentially planar, with a maximum deviation of 0.068 (2) Å for one of the amino N atoms. The sorbate anion adopts an extended conformation. In the crystal structure, the protonated N atom and one of the two amino-group H atoms are hydrogen bonded to the sorbate anion through a pair of N-H⋯O hydrogen bonds, forming an R(2) (2)(8) ring motif. The ion pairs are further connected via inter-molecular N-H⋯O and C-H⋯O hydrogen bonds, forming two-dimensional networks parallel to (100).
In the title compound, C(10)H(6)N(2), the mol-ecule is almost planar, with an r.m.s. deviation of 0.014 Å. The dihedral angle between the aromatic rings is 1.28 (16)°. In the crystal, mol-ecules are stacked along the a axis by way of weak aromatic π-π stacking inter-actions between the benzene and pyridine rings of adjacent mol-ecules [centroid-centroid separation = 3.7943 (19) Å].
In the title salt, C(6)H(9)N(2) (+)·C(6)H(7)O(2) (-)·2H(2)O, the non-H atoms of the 2-amino-4-methyl-pyridinium cation are coplanar, with a maximum deviation of 0.010 (1) Å. In the crystal structure, the pyridinium N atom and the 2-amino group of the cation are hydrogen bonded to the carboxyl-ate O atoms of the anion via a pair of N-H⋯O hydrogen bonds, forming an R(2) (2)(8) ring motif. The sorbate anions and water mol-ecules are linked through O-H⋯O hydrogen bonds, forming R(10) (10)(28) and R(6) (4)(12) ring motifs. The motifs form part of a three-dimensional framework.
Two independent mol-ecules comprise the asymmetric unit of the title compound, C(12)H(11)N(3)O(2). 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 mol-ecules 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 mol-ecule [respective torsion angles = -11.7 (5) and 0.8 (5)°]. Intra-molecular N-H⋯O hydrogen bonds preclude the amine H atoms from forming significant inter-molecular inter-actions. The crystal packing features inter-molecular 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.
The asymmetric unit of the title salt, C(5)H(6)BrN(2) (+)·C(7)H(5)O(6)S(-), contains two independent 2-amino-5-bromo-pyridinium cations and two independent 3-carb-oxy-4-hy-droxy-benzene-sulfonate anions. The hy-droxy and carboxyl groups of the anions are involved in intra-molecular O-H⋯O hydrogen bonds, which generate S(6) ring motifs. In the crystal structure, the ions are linked by N-H⋯O and O-H⋯O hydrogen bonds into a two-dimensional network parallel to (110). Adjacent networks are linked via C-H⋯O hydrogen bonds.
In the title mol-ecule, C(12)H(10)N(2)O(4), the pyridine and benzene rings are almost orthogonal [dihedral angle = 86.69 (11)°], with the pyridine N atom directed towards the centre of the benzene ring. The -NO(2) [O-N-C-C = -26.1 (3)°] and -OMe [C-O-C-C = 166.5 (2)°] substituents are not coplanar with their respective aromatic rings. In the crystal, supra-molecular layers in the ab plane are formed via C-H⋯π inter-actions involving methyl H atoms and the pyridine and benzene rings. Short N-O⋯π contacts (where the π-system is derived from the pyridine ring) occur between layers in the c-axis direction.
In the title mol-ecule, C(14)H(9)N(3)O(3), the dihedral angle between the quinoxaline and benzene rings is 77.13 (9)°. The mol-ecule is twisted about the ether-benzene O-C bond, with a C-O-C-C torsion angle of -102.8 (2)°. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds, forming layers in the ab plane, with one nitro O atom accepting two such inter-actions. The layers stack along the c-axis direction via weak C-H⋯π inter-actions.
Two independent mol-ecules comprise the asymmetric unit in the title compound, C(11)H(11)N(3). These differ in terms of the relative orientations of the aromatic rings: the first is somewhat twisted, while the second is approximately planar [dihedral angles between the pyrimidine and phenyl rings = 39.00 (8) and 4.59 (11)°]. The mol-ecules also form distinct patterns in their hydrogen bonding. The first independent mol-ecule forms centrosymmetric dimers featuring an eight-membered {HNCN}(2) synthon. The second independent mol-ecule forms an N-H⋯N hydrogen bond with the other pyrimidine N atom of the first mol-ecule. Thereby, tetra-meric aggregates are formed. These associate via C-H⋯N and C-H⋯π inter-actions, consolidating the crystal packing.