4-Aminopyridinium 2-chloro-4-nitrobenzoate monohydrate

In the title hydrated molecular salt, C5H7N2+·C7H3ClNO4−·H2O, the ions and water molecules assemble into ribbons of R65(22) rings along the c axis via O(water)—H...O−, N+—H...O(water) and N—H...O− hydrogen bonds. N—H...O− hydrogen bonds connect adjacent ribbons along the c-axis direction via R44(12) rings, forming hydrogen-bonded layers. The CO2 and NO2 groups make dihedral angles of 81.8 (2) and 1.4 (2)°, respectively, with the ring in the anion

Crystal structure of 5-[2-(2,4,6-tribromophenyl)diazenyl]tropolone

The title compound {systematic name: 2-hydroxy-5-[2-(2,4,6-tribromophenyl)diazen-1-yl]cyclohepta-2,4,6-trien-1-one}, C13H7Br3N2O2, is essentially planar, with an r.m.s. deviation of 0.054 Å. The molecular structure is fixed in the azo tautomer by intramolecular C—H...N interactions, with O—H...O hydrogen bonds creating linked dimers. Charge-transfer interactions are observed, with the segregated stacks linked by Br...Br interactions