Piperazine-1,4-diium pyridine-2,3-dicarboxyl­ate methanol monosolvate

The title solvated molecular salt, C(4)H(12)N(2) (2+)·C(7)H(3)NO(4) (2−)·CH(3)OH or (pipzH(2))(py-2,3-dc)·MeOH, was prepared by the reaction of pyridine-2,3-dicarb­oxy­lic acid (py-2,3-dcH(2)) and piperazine (pipz) in methanol (MeOH) as solvent. One of the two carboxylate groups of the acid fragment is nearly perpendicular to the pyridine ring and the other is almost in its plane [C—C—C—O torsion angles = −85.50 (11) and 88.07 (11)° and N—C—C—O torsion angles = −176.31 (8) and 5.41 (13)°]. In the crystal, the components are linked by O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds, generating a three-dimensional network.