Supramolecular hydrogen-bond motifs in chiral and racemic molecular salts: A comparison of (S)-2-methyl piperizinium hydrogen phosphite monohydrate, C₅H₁₄N₂·HPO₃·H₂O and (R,S)-2-methyl piperizinium hydrogen phosphite 2.23 hydrate, C₅H₁₄N₂·HPO₃·2.23H₂O

The crystal structures of C₅H₁₄N₂·HPO₃·H₂O (1) and C₅H₁₄N₂·HPO₃·2.23H₂O (2) are described and compared. Compound 1 contains homochiral (S)-2-methyl piperizinium cations, hydrogen phosphite ions and water molecules. The components are linked by N-H⋯O and O-H⋯O hydrogen bonds into a three-dimensional network. In compound 2, racemic (R,S)-2-methyl piperizinium cations combine with the same anions and water molecules to generate a far more complex, high symmetry "supramolecular" structure, which features distinctive R⁶₆(12) loops and helical C(2) chain hydrogen-bonding motifs involving the water molecules. Crystal data: 1 (C₅H₁₇N₂O₄P), Mr = 200.18, orthorhombic, P2₁2₁2₁ (No. 19), Z = 4, a = 8.564 (5) Å, b = 9.593 (6) Å, c = 11.607 (6) Å, V = 953.6 (9) ų, R(F) = 0.066, wR(F²) = 0.081. 2 (C₅H_19.47N₂O_5.24P), M_r = 222.49, trigonal, R3 (No. 148), Z = 18, a = 31.075 (2) Å, c = 6.1875 (4) Å, V = 5174.5 (6) ų, R(F) = 0.044, wR(F²) = 0.107.