Supramolecular structures of six adenine-carboxylic acid complexes

Studies concentrating on hydrogen bonding between the bases of DNA and small molecule proton acceptor/donators have led to an increased understanding of the role such complexes have in DNA binding. Here anhydrous and solvated multicomponent crystals of adenine have been prepared with benzoic acid, adipic acid, salicylic acid, 2,6-dihydroxybenzoic acid and 3,5-dihydroxybenzoic acid. The six crystalline forms reported are an anhydrous cocrystal, a methanolated cocrystal, an anhydrous proton-transfer complex, a hydrated proton-transfer complex, a methanolated proton-transfer complex and a doubly hydrated salt. All products were formed in solution and obtained by the slow evaporation technique. A comparison of hydrogen bonding motifs in the products is presented.