Hydrogen-bonded supramolecular motifs in pyrimethaminium 4-methylbenzoate, pyrimethaminium 3-hydroxypicolinate and pyrimethaminium 2,4-dichlorobenzoate.

In 2,4-diamino-5-(4-chlorophenyl)-6-ethylpyrimidin-1-ium (pyrimethaminium, PMNH) 4-methylbenzoate, C(12)H(14)ClN(4)(+) x C(8)H(7)O(2)(-), (I), pyrimethaminium 3-hydroxypicolinate, C(12)H(14)ClN(4)(+) x C(6)H(4)NO(3)(-), (II), and pyrimethaminium 2,4-dichlorobenzoate, C(12)H(14)ClN(4)(+) x C(7)H(3)Cl(2)O(2)(-), (III), the PMNH cations interact with the carboxylate groups of the corresponding anion via nearly parallel N-H...O hydrogen bonds, forming R(2)(2)(8) ring motifs. A description of the observed arrays of quadruple hydrogen bonds in (I) and (II) in terms of hydrogen donors and acceptors (the DA model), their graph-set motifs and the resulting supramolecular ladder is given. In (III), supramolecular chains along the b axis and helical chains along the a axis are formed via N-H...O hydrogen bonds involving the 2-amino and 4-amino groups of the PMNH cation, respectively. Weak Cl...Cl interactions are also found in (III).