Yoswathananont Nungruethai, Sada Kazuki, Miyata Mikiji, Akita Shigendo, Nakano Kazunori
Department of Material and Life Science, Graduate School of Engineering, Osaka University and Handai FRC, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
Org Biomol Chem. 2003 Jan 7;1(1):210-4. doi: 10.1039/b210544f.
Competitive recrystallizations of cholic acid (CA) from 1:1 binary mixtures of seven mono-substituted benzenes are demonstrated. The order of preference for guests to be incorporated into the cholic acid crystals are as follows: benzene, toluene > n-amylbenzene, n-hexylbenzene > ethylbenzene, n-propylbenzene, n-butylbenzene. These seven compounds afford bilayer type inclusion crystals that are classified into four types based on the host frameworks and host-guest stoichiometries. The order of selective enclathration corresponds to the four types as follows: 1:1 alpha G > 2:1 alpha G > 1:1 beta T or 2:1 alpha T. The preference for the alpha G type was also confirmed by investigating the host frameworks of the crystals obtained from binary mixtures. The dependence of the selectivity on the different types of CA crystals can be understood in terms of the fit of the guest molecule in the host cavity.
