Abstract
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.
Users
Please
log in to take part in the discussion (add own reviews or comments).