Supramolecular hydrogen-bonding patterns in two cocrystals of the N(7)-H tautomeric form of N6-benzoyladenine: N6-benzoyladenine-3-hydroxypyridinium-2-carboxylate (1/1) and N6-benzoyladenine-DL-tartaric acid (1/1).

Two novel cocrystals of the N(7)-H tautomeric form of N⁶-benzoyladenine (BA), namely N⁶-benzoyladenine-3-hydroxypyridinium-2-carboxylate (3HPA) (1/1), C₁₂H₉N₅O·C₆H₅NO₃, (I), and N⁶-benzoyladenine-DL-tartaric acid (TA) (1/1), C₁₂H₉N₅O·C₄H₆O₆, (II), are reported. In both cocrystals, the N⁶-benzoyladenine molecule exists as the N(7)-H tautomer, and this tautomeric form is stabilized by intramolecular N-H...O hydrogen bonding between the benzoyl C=O group and the N(7)-H hydrogen on the Hoogsteen site of the purine ring, forming an S(7) motif. The dihedral angle between the adenine and phenyl planes is 0.94 (8)° in (I) and 9.77 (8)° in (II). In (I), the Watson-Crick face of BA (N6-H and N1; purine numbering) interacts with the carboxylate and phenol groups of 3HPA through N-H...O and O-H...N hydrogen bonds, generating a ring-motif heterosynthon [graph set R₂²(6)]. However, in (II), the Hoogsteen face of BA (benzoyl O atom and N7; purine numbering) interacts with TA (hydroxy and carbonyl O atoms) through N-H...O and O-H...O hydrogen bonds, generating a different heterosynthon [graph set R₂²(4)]. Both crystal structures are further stabilized by π-π stacking interactions. [ABSTRACT FROM AUTHOR]