Water of Hydration in 2:1 Hydrogen-Bonded Complexes between 1,5,7-Triazabicyclo[4.4.0]dec-5-ene and Dicarboxylic Acids

Crystalline (2:1) complexes between a basic bicyclic guanidine derivative and four dicarboxylic acids have been prepared and characterized by single-crystal X-ray diffraction methods. Classical R22(8) hydrogen-bonded ring motifs involving charge-assisted +N–H···O– interactions occur in three of these crystals. The high affinity toward water molecules is manifested by cocrystallization of water in three structures of which two display distinct hydrophilic channels with extensive hydrogen bonding in intricate hydrogen-bonded water tapes.