2013. 54, 5 UDC 548.737 A COCRYSTAL OF CAFFEINE AND DIPICOLINIC ACID: SYNTHESIS, CHARACTERIZATION, X-RAY CRYSTALLOGRAPHY, AND SOLUTION STUDIES A. Moghimi 1, H.R. Khavasi2, F. Dashtestani1, D. Kordestani3 , E. Behboodi 1, B. Maddah4 1Department of Chemistry, Islamic Azad University, Tehran North Branch, Tehran, Iran E-mail: f.dashtestani@gmail.com 2Department of Chemistry, Shahid Beheshti University, G. C., Tehran, Iran 3Department of Chemistry, Razi University, Kermanshah, Iran 4Department of Chemistry, Imam Hossein University, Tehran, Iran Received June, 21, 2012 A reaction between caffeine (caff) and dipicolinic acid = 2,6-pyridine dicarboxylic acid (pydc.H2) in water results in the formation of a cocrystal compound (pydc.H2.H2O)(caff) 1. <...> The characterization of the resulting crystallohydrate is performed using 1H, 13C 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 — stacking between the pydc.H2 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. <...> Keywords: crystal chemistry, single crystal X-ray diffraction, proton transfer, hydrogen bonding, caffeine, dipicolinic acid. <...> Smith and co-workers have prepared a series of cocrystal compounds from the reaction of 2-aminopyrimidine, 3-amino-1,2,4-triazole, and 5-nitroquinoline with heterocyclic carboxylic acids, such as 2,6-dihydroxybenzoic acid, 4-aminobenzoic acid, phenoxyacetic acid, salicylic acid [ 3 ], indole-3-acetic acid, thiophen-2-carboxylic acid [ 4 ], and indole-2-acetic acid [ 5 ]. <...> The design of cocrystal compounds from pharmaceutical agents has already been of interest in the field of solid-state science [ 6 ]. <...> The role of cocrystals in pharmaceutical science has been reviewed by Zaworotko et al. [ 7 ]. <...> In this contribution, the series of cocrystals of caffeine with adipic acid and hydroxyl naphthoic acids have been reported [ 8—10 ]. <...> In connection with such compounds, we became interested in making a cocrystal compound containing caffeine and dipicolinic acid. <...> Our goal was to investigate the influence of caffeine on the structural properties of the resulting <...>