RESUMO
In the title compound (systematic name: 6-benzylamino-7H-purin-3-ium p-toluenesulfonate), C(12)H(12)N(5)(+)·C(7)H(7)O(3)S(-), the adenine moiety exists as the N(3)-protonated N(7)-H tautomer. The dihedral angle between the adenine ring system and the phenyl ring is 82.76 (11)°. Two of the sulfonate O atoms form C-H···O and N-H···O hydrogen bonds with the H atoms on the N and C atoms in the 3- and 8-positions, respectively, of the adenine moiety, leading to a zigzag chain. Two antiparallel zigzag chains are linked by the remaining sulfonate O atom through Hoogsteen-site H atoms (i.e. those on the N atoms in the 6- and 7-positions) of the adenine moiety, leading to a double chain. An annulus formed by a pair of inversion-related anions and cations has been identified. An intramolecular toluenesulfonate-phenyl C-H···π interaction is also present.