Crystal structure of 2-amino-3-methylpyridinium ortho-phthalate

A new crystal of 2-amino-3-methylpytidinium ortho-phthalate has been prepared and characterized by X-ray crystallography. The salt crystallizes in the monoclinic space group P2(1)/c with a = 11.015(2) Angstrom, b = 11.057(2) Angstrom, c = 15.767(2) Angstrom, alpha = 90.00degrees beta = 96.220(10)degrees, gamma = 90.00degrees, V = 1909.0(5) Angstrom(3), Z = 4. In the cell unit, the phthalate anion is linked with two pyridinium cations by NHO hydrogen bond on both sites of annular and exocyclic nitrogen atoms. The two pyridinium cations are arranged in a face-to-face pattern with a dihedral angle of 7.3degrees and a shortest aspectant distance of 3.4(1) Angstrom between them, indicating the existence of pi-pi interaction. The C(5) atom is an electron donating center. The exocyclic N atom is an electron receiving center, which is consistent with features of imino resonance evidenced by bond lengths and angles. In the cell unit, two entities of pyridinium cation are aligned with each other in a face-to-face manner of electron receiving to donating center.