Structural Study of Salicylic Acid Salts of a Series of Azacycles and Azacrown Ethers

Interaction of salicylic acid (saH) with the azacycles pipendine (pipe) and meso-5 7,7,12 12 14-hexamethyl-1,4,8,11-tetraazacyclotetradecane (teta) and with the aza-crown ethers aza-12-crown-4 (A12C4), benzoaza-15-crown-5 (BA15C5), aza-18-crown-6 (A18C6), and diaza-18-crown-6 (DA18C6) afforded the proton-transfer complexes (organic salts) of compositions [pipeH][sa], [tetaH(2)][sa](2), [A12C4H][sa], [BA15C5H][sa], [A18C6H][sa] 2H(2)O, and [DA18C6H(2)][sa](2) 3H(2)O whose structures were determined by a single crystal X-ray method These products were also obtained by the same synthetic conditions starting from acetylsalicylic acid (aspirin) as a result of hydrolysis The charge-assisted N-H center dot center dot center dot O hydrogen-bond provides the main driving force for direct binding of sa with cyclic azoma cations The crystal packing is also supported by weak C-H center dot center dot center dot O hydrogen bonding and edge-to-face pi center dot center dot center dot pi intermolecular interactions