Supra­molecular inter­actions in 2,6-di­amino-4-chloro­pyrimidin-1-ium 5-chloro­salicylate and bis­(2,6-di­amino-4-chloro­pyrimidin-1-ium) naphthalene-1,5-di­sulfonate

The crystals of two new salts, 2,6-di­amino-4-chloro­pyrimidin-1-ium 5-chloro­salicylate, C(4)H(6)ClN(4) (+)·C(7)H(4)ClO(3) (−), (I), and bis­(2,6-di­amino-4-chloro­pyrimidin-1-ium) naphthalene-1,5-di-sulfonate, 2C(4)H(6)ClN(4) (+)·C(10)H(6)O(6)S(2) (2−), (II), have been synthesized and characterized by single-crystal X-ray diffraction. In both compounds, the N atom of the pyrimidine group in between the amino substituents is protonated and the pyrimidinium cation forms a pair of N—H⋯O hydrogen bonds with the carboxyl­ate/sulfonate ion, leading to a robust R (2) (2)(8) motif (supra­molecular heterosynthon). In compound (I), a self-complementary base pairing involving the other pyrimidinium ring nitro­gen atom and one of the amino groups via a pair of N—H⋯N hydrogen bonds [R (2) (2)(8) homosynthon] is also present. In compound (II), the crystallographic inversion centre coincides with the inversion centre of the naphthalene-1,5-di­sulfonate ion and all the sulfonate O atoms are hydrogen-bond acceptors, generating fused-ring motifs and a quadruple DDAA array. A halogen-bond (Cl⋯Cl) inter­action is present in (I) with a distance and angle of 3.3505 (12) Å and 151.37 (10)°, respectively. In addition, a C—Cl⋯π inter­action and a π–π inter­action in (I) and a π–π inter­action in (II) further stabilize these crystal structures.