Induction and inhibition of preferential enrichment by controlling the mode of the polymorphic transition with seed crystals.
Both induction and inhibition of "preferential enrichment", an unusual symmetry-breaking enantiomeric-resolution phenomenon observed upon simple recrystallization of a certain kind of racemic crystals from organic solvents, have been successfully achieved by controlling the mode of the polymorphic transition during crystallization with appropriate seed crystals. Such control of the polymorphic transition can be interpreted in terms of a novel phenomenon consisting of 1) the adsorption of prenucleation aggregates, 2) the heterogeneous nucleation and crystal growth of a metastable crystalline form, and 3) the subsequent polymorphic transition into the more stable form; these three processes occur on the same surface of a seed crystal. We refer to this phenomenon as an "epitaxial transition", which has been confirmed by means of in situ attenuated total reflection (ATR) FTIR spectroscopy in solution and the solid state, differential scanning calorimetry (DSC) measurements of the deposited crystals, and X-ray crystallographic analysis of the single crystals or the direct-space approach employing the Monte Carlo method with the Rietveld refinement for the structure solution from the powder X-ray diffraction data.
Tamura
Rui
R
Graduate School of Human and Environmental Studies, Kyoto University, Kyoto 606-8501, Japan. tamura-r@mbox.kudpc.kyoto-u.ac.jp
Mizuta
Masayuki
M
Yabunaka
Shinsuke
S
Fujimoto
Daisuke
D
Ariga
Tomomi
T
Okuhara
Shinichiro
S
Ikuma
Naohiko
N
Takahashi
Hiroki
H
Tsue
Hirohito
H