A COCRYSTAL OF CAFFEINE AND DIPICOLINIC ACID: SYNTHESIS, CHARACTERIZATION, X-RAY CRYSTALLOGRAPHY, AND SOLUTION STUDIES

作者：Moghimi A^*; Khavasi H R; Dashtestani F; Kordestani D; Behboodi E; Maddah B

来源：Journal of Structural Chemistry, 2013, 54(5): 990-995.

DOI：10.1134/S0022476613050247

• crystal chemistry
• single crystal X-ray diffraction
• proton transfer
• hydrogen bonding
• caffeine
• dipicolinic acid.

A reaction between caffeine (caff) and dipicolinic acid = 2,6-pyridine dicarboxylic acid (pydc.H-2) in water results in the formation of a cocrystal compound (pydc.H-2.H2O)(caff) 1. The characterization of the resulting crystallohydrate is performed using H-1, C-13 NMR and IR spectroscopy and X-ray crystallography. X-ray crystal structure analysis reveals the presence of both starting materials and water in the lattice. It also indicates intensive intermolecular H bonding interactions between carboxylic acid, caffeine, and water as well as pi-pi stacking between the pydc.H-2 and caff rings as constituents of the cocrystal. The hydrogen bonding and non-covalent interactions play roles in the formation of the cocrystal. The crystal system is triclinic with the space group P-1 and two formula units per unit cell. The unit cell parameters are a = 6.906(2) , b = 8.451(3) , c = 14.68 (4) with alpha = 81.51(3)A degrees, beta = 78.47(3)A degrees, and gamma = 78.14(3)A degrees. The final R value is 0.0660 for 7943 measured reflections.

• 出版日期2013-9