Supra­molecular architecture in a co-crystal of the N(7)—H tautomeric form of N6-benzoyl­adenine with adipic acid (1/0.5)

The asymmetric unit of the title co-crystal, C12H9N5O·0.5C6H10O4, consists of one mol­ecule of N6-benzoyl­adenine (BA) and one half-mol­ecule of adipic acid (AA), the other half being generated by inversion symmetry. The dihedral angle between the adenine and phenyl ring planes is 26.71 (7)°. The N6-benzoyl­adenine mol­ecule crystallizes in the N(7)—H tautomeric form with three non-protonated N atoms. This tautomeric form is stabilized by intra­molecular N—H⋯O hydrogen bonding between the carbonyl (C=O) group and the N(7)—H hydrogen atom on the Hoogsteen face of the purine ring, forming an S(7) ring motif. The two carboxyl groups of adipic acid inter­act with the Watson–Crick face of the BA mol­ecules through O—H⋯N and N—H⋯O hydrogen bonds, generating an R22(8) ring motif. The latter units are linked by N—H⋯N hydrogen bonds, forming layers parallel to (10-5). A weak C—H⋯O hydrogen bond is also present, linking adipic acid mol­ecules in neighbouring layers, enclosing R22(10) ring motifs and forming a three-dimensional structure. C=O⋯π and C—H⋯π inter­actions are also present in the structure.