Crystal structure and Hirshfeld surface analysis of 2,4-di­amino-6-phenyl-1,3,5-triazin-1-ium 4-methyl­benzene­sulfonate

In the title mol­ecular salt, C(9)H(10)N(5) (+)·C(7)H(7)O(3)S(−), the asymmetric unit consists of a 2,4-di­amino-6-phenyl-1,3,5-triazin-1-ium cation and a 4-methyl­benzene­sulfonate anion. The cation is protonated at the N atom lying between the amine and phenyl substituents. The protonated N and amino-group N atoms are involved in hydrogen bonding with the sulfonate O atoms through a pair of inter­molecular N—H⋯O hydrogen bonds, giving rise to a hydrogen-bonded cyclic motif with R (2) (2)(8) graph-set notation. The inversion-related mol­ecules are further linked by four N—H⋯O inter­molecular inter­actions to produce a complementary DDAA (D = donor, A = acceptor) hydrogen-bonded array, forming R (2) (2)(8), R (4) (2)(8) and R (2) (2)(8) ring motifs. The centrosymmetrically paired cations form R (2) (2)(8) ring motifs through base-pairing via N—H⋯N hydrogen bonds. In addition, another R (3) (3)(10) motif is formed between centrosymetrically paired cations and a sulfonate anion via N—H⋯O hydrogen bonds. The crystal structure also features weak S=O⋯π and π–π inter­actions. Hirshfeld surface and fingerprint plots were employed in order to further study the inter­molecular inter­actions.