Three polymorphic forms of the co-crystal 4,4'-bipyridine/pimelic acid and their structural, thermal, and spectroscopic characterization.
Three crystal forms of the co-crystal 4,4'-bipy/pimelic acid (bipy: bipyridine), [NH(4)C(5)-C(5)H(4)N][HOOC(CH(2))(5)COOH], have been prepared and their relationship investigated by single-crystal X-ray diffraction, variable-temperature X-ray powder diffraction, differential scanning calorimetry and solid-state NMR spectroscopy. Both X-ray and NMR spectroscopic results indicate that no proton transfer takes place, that is, the three crystal forms are true co-crystals of neutral molecules. Forms I and II both convert into Form III at high temperature, Forms II and III being the thermodynamically stable forms at room and high temperature, respectively.
Braga
Dario
D
Dipartimento di Chimica "G. Ciamician", Università degli studi di Bologna, Via Selmi 2, 40126 Bologna, Italy.
Palladino
Giuseppe
G
Polito
Marco
M
Rubini
Katia
K
Grepioni
Fabrizia
F
Chierotti
Michele R
MR
Gobetto
Roberto
R