Crystal structures of 2-methyl­pyridinium hydrogen 2,3-bis­(4-methyl­benzo­yloxy)succinate and bis-[4-methyl­pyridinium hydrogen 2,3-bis­(4-methyl­benzo­yloxy)succinate] penta­hydrate

The title salt (I), C(6)H(8)N(+)·C(20)H(17)O(8) (−), comprises a 2-methyl­pyridinium cation and a 2,3-bis­(4-methyl­benzo­yloxy)succinate mono-anion while the salt (II), 2C(6)H(8)N(+)·2C(20)H(17)O(8) (−)·5H(2)O, consists of a pair of 4-methyl­pyridinium cations and 2,3-bis­(4-methyl­benzo­yloxy)succinate mono-anions and five water mol­ecules of solvation in the asymmetric unit. In (I), the dihedral angle between the aromatic rings of the anion is 40.41 (15)°, comparing with 43.0 (3) and 85.7 (2)° in the conformationally dissimilar anion mol­ecules in (II). The pyridine ring of the cation in (I) is inclined at 23.64 (16) and 42.69 (17)° to the two benzene moieties of the anion. In (II), these comparative values are 4.7 (3), 43.5 (3)° and 43.5 (3), 73.1 (3)° for the two associated cation and anion pairs. The crystal packing of (I) is stabilized by inter-ionic N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds as well as weak C—H⋯π inter­actions, linking the ions into infinite chains along [100]. In the crystal packing of (II), the anions and cations are also linked by N—H⋯O and O—H⋯O hydrogen bonds involving also the water mol­ecules, giving a two-dimensional network across (001). The crystal structure is also stabilized by weak C—H⋯O and C—H⋯π inter­actions.