3-Methyl­anilinium picrate

In 3-methyl­anilinium picrate (3-MAP), C₇H₁₀N⁺·C₆H₂N₃O₇^-, one of the nitro groups in the picrate ion is rotationally disordered with site occupancy factors of 0.80 and 0.20. The expected proton transfer took place between picric acid and 3-methyl­aniline, and the amine group is hydrogen bonded to two of the phenolate O atoms. The ortho-nitro groups deviate greatly from the benzene plane of the picrate ion, facilitating hydrogen-bond formation. While the cations are stacked as columns along the [001] direction, the anions are stacked in an offset fashion.

1-(4-Methyl­piperdinemeth­yl)-2-(4-bromo­phen­yl)-6-meth­yl-8-trifluoromethyl­imidazo[1,2-a][1,8]naph­thyridinium picrate

The title mol­ecular complex, C₂₅H₂₅BrF₃N₄⁺·C₆H₂N₃O₇⁻, crystallizes with two pairs of cations and anions in the asymmetric unit. While the orientations of the two cations are nearly parallel to one another, this is not so for the anions. The imidazonaphthyridine moiety is planar and the methyl­piperidine group is approximately perpendicular to it and adopts an ideal chair conformation. The planes of the bromo­phen­yl rings deviate from the planes of the imidazonaphthyridine moieties by 30.2 (2) and 22.6 (3)° in the two cations, making a marked difference in the overall conformation of the cations. The N—H...N hydrogen bond forms an intra­molecular ring pattern S(7) in both cations. The anions and cations are connected through N—H...O, C—H...O and C—H...F hydrogen bonds.

Ethyl­aminium picrate

In the title salt, C₂H₈N⁺·C₆H₂N₃O₇⁻, there is complete transfer of the OH proton from picric acid to the amine. The picrate anions lie almost parallel to the monoclinic (101) plane and are connected by O...O short contacts. The ethyl­aminium and picrate ions are linked through N—H...O and C—H...O hydrogen bonds along the crystallographic b axis. In the picrate anion, tilting of the para-nitro group is a consequence of C—H...O hydrogen bonding between the ions.

3-(Dimethyl­ammonio)propanaminium dipicrate

In the title complex, C₅H₁₆N₂²⁺·2C₆H₂N₃O₇⁻, the two picrate anions lie almost parallel to each other and have possible π–π inter­actions between them. One of the anions is involved in limited N—H...O bonds, whereas the other engages in extensive N—H...O and C—H...O hydrogen bonds. Tilting of one of the ortho nitro groups in the picrate anion is influenced by the N—H...O hydrogen bond. The dimethyl­aminopropyl­ammonium and picrate ions are linked through N—H...O and C—H...O hydrogen bonds, forming chains along the crystallographic b axis. The anions form near-helical columns along the b axis owing to the presence of a 2₁ screw and are separated by nearly linear cationic chains.

1-Dimethyl­ammoniomethyl-6,8-dimethyl-2-phenyl-1,2-dihydro­imidazo[1,2-a][1,8]naphthyridine picrate monohydrate

In the title salt, C₂₁H₂₃N₄⁺·C₆H₂N₃O₇⁻·H₂O, the dimethyl­ammonio­methyl side chain is oriented nearly perpendicular to the imidazonaphthyridine moiety, which is nearly planar. In the crystal structure, inter­molecular N—H...O and O—H...O hydrogen bonds link two cations, two anions and two water mol­ecules into clusters, which further inter­act via weak C—H...O hydrogen bonds.

Triethylaminium picrate

The title salt, C₆H₁₆N⁺·C₆H₂N₃O₇⁻, crystallizes with two pairs of cations and anions in the asymmetric unit. Anions A and B are stacked alternately in the (020) plane to form anionic columns having an ABABAB… sequence, with possible π–π inter­actions between them. The cationic columns surround these columns in an almost hexa­gonal fashion, with each column of the same type of cation, A or B. The anions and cations are connected through lone N—H...O and by other C—H...O hydrogen bonds. N—H...O and C—H...O hydrogen bonds involving A-and B- type ions form a cyclic pattern with a graph-set descriptor R₂²(10).

Cyclo­hexyl­ammonium picrate

In the crystal structure of the title salt, C₆H₁₄N⁺·C₆H₂N₃O₇^-, picrate anions lie parallel to one another with a relative orientation of nearly 120°. The protonated N atom of the cation makes one linear and two bifurcated hydrogen bonds with three neighbouring picrate ions. The centrosymmetrically related anions and cations form hydrogen-bonded graph-set motifs of R₄²(8) and R₄⁴(12) alternately along the [010] direction.

Piperidinium picrate

In the title compound, C₅H₁₂N⁺·C₆H₂N₃O₇⁻, the protonated N atom of the cation makes one linear and two bifucated hydrogen bonds with two neighbouring picrate anions. Centrosymmetrically related anions and cations form a hydrogen-bonded network with a graph-set motif R₄⁴(12). The picrate ions are parallel to one another and governed by π–π inter­actions; they form columns along the b axis.