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Polymorphism in β-cyclodextrin–benzoic acid inclusion complex: a kinetically controlled crystal growth according to the Ostwald’s rule

“…2). The preferred orientation of BA with the COOH group directing toward the b-CD O-6 side observed in the crystal forms I and II is consistent with the results obtained in solution by NMR spectroscopy 10 and potentiometric titration 11 as well as in the gas phase by FAB mass spectrometry 12 and theoretical calculations. 13 The two BAs are maintained in positions by hydrogen bonding with two bridging water sites W-17 (1.0) and W-2 (0.…”

“…The crystallographic result gives better insight into the b-CD-BA inclusion complex than do the others previously reported. [10][11][12][13][14] For example, the results obtained in solution by NMR, 10 by potentiometric titration; 11 in the gas phase by FAB mass spectrometry, 12 by theoretical calculations 13 have shown that the host-guest stoichiometry is 1:1, the BA aromatic ring is parallel to the CD molecular axis and the COOH group points toward the narrower rim of the cone. In the solid state, thermal analyses and X-ray powder diffraction have revealed significant interactions between b-CD and BA in both physical and kneaded mixtures with a 1:1 host-guest molar ratio.…”

Cyclodextrin Rotaxanes and Polyrotaxanes

“…The water solubility of these inclusion compounds enables detection of complex formation in solution by spectroscopic methods, such as NMR, UV, fluorescence, or circular dichroism spectroscopy, as well as by thermodynamic methods, e.g., microcalorimetry 60 or density, , or by solubility measurements. Likewise, mass spectrometry was used . The kinetics of complex formation are generally ultrafast, as no steric barrier has to be overcome .…”

“…Likewise, mass spectrometry was used. 63 The kinetics of complex formation are generally ultrafast, as no steric barrier has to be overcome. 64 The fast orientational dynamics within CD inclusion compounds were measured by time-resolved polarization spectroscopy.…”