2-Amino-4-methyl­pyridinium 6-carb­oxy­pyridine-2-carboxyl­ate sesquihydrate

In the title compound, C6H9N2 +·C7H4NO4 −·1.5H2O, extensive O—H⋯O, O—H⋯N, N—H⋯O and C—H⋯O hydrogen bonds, as well as ion pairing, π–π stacking inter­actions [centroid–centroid distances = 3.4690 (8) and 3.6932 (8) Å between aromatic rings] occur in the crystal. There are hydrogen-bonding inter­actions between water mol­ecules, which result in cyclic tetra­meric water clusters. One of the water O molecules has half occupancy. In the anion molecules, the –CO2 and –CO2H groups make torsion angles of 1.73 (18) and −12.14 (18)° with respect to the ring

Acridinium (6-carboxypyridine-2-carboxylato)(pyridine-2,6-dicarboxylato)zincate(II) pentahydrate

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

2-Amino-1-methyl-4-oxo-4,5-dihydro-1H-imidazol-3-ium chloride

In the crystal structure of the title compound, C4H8N3O+·Cl−, N—H...Cl hydrogen bonds link the components into chains along [010]. In addition, weak C—H...Cl hydrogen bonds link the chains into a two-dimensional network perpendicular to (001)