Supramolecular ion channels from transmembrane cholic acid derivatives


Yoshiaki Kobuke,, Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192, Japan
Two 7,12-dimethylether derivative of cholic acids were linked at the 3,3'-positions to make a transmembrane unit 1. The similar unit 2 was prepared from cholic acids themselves. Two transmembrane units 1- and 2-types were connected to give 3 and 4, respectively. Rectification behavior was observed for the channel from 1-type in contrast to linear I-V characteristics for the channel from 2-type. Furthermore three 2-type units were connected. The conductance of this channel showed only one state, 4 pS. This was the smallest compared to 8.6 pS for 4 and 9.5 and 25.3 pS for 2. Considering that the conductance of resorcinarene channel having four dehydrocholic acids was 8.8 pS, the numbers of association units in these supramolecular channels were assiged. These results suggest that the 1-type channels form relatively loose internal structure, while 2-type channels are relatively rigid to make possible to assign the specific number of supramolecular channel units.

Membrane Active, Synthetic Organic Compounds
1:30 PM-5:05 PM, Sunday, 28 August 2005 Washington DC Convention Center -- Ballroom C, Oral

Division of Organic Chemistry

The 230th ACS National Meeting, in Washington, DC, Aug 28-Sept 1, 2005