Supramolecular hydrogen-bonding patterns in a 1:1 co-crystal of the N(7)—H tautomeric form ofN6-benzoyladenine with 4-hydroxybenzoic acid

Abstract

The asymmetric unit of the title co-crystal, C12H9N5O·C7H6O3, contains one molecule ofN6-benzoyladenine (BA) and one molecule of 4-hydroxybenzoic acid (HBA). TheN6-benzoyladenine (BA) has an N(7)—H tautomeric form with nonprotonated N-1 and N-3 atoms. This tautomeric form is stabilized by a typical intramolecular N—H...O hydrogen bond between the carbonyl (C=O) group and the N(7)—H hydrogen on the Hoogsteen face of the purine ring, forming a graph-setS(7) ring motif. The primary robustR22(8) ring motif is formed in the Watson–Crick faceviaN—H...O and O—H...N hydrogen bonds (involving N1, N6—H and the carboxyl group of HBA). Weak interactions, such as, C—H...π and π–π are also observed in this crystal structure.