Tetrahedron p. 423 - 446 (1998)
Update date:2022-08-04
Topics:
Otsuka, Hideyuki
Suzuki, Yoshio
Ikeda, Atsushi
Araki, Koji
Shinkai, Seiji
The reaction of 1.3.5-tri-O-alkylated calix[6]arenes with 1,3,5- tris(bromomethyl)benzene yielded capped calix[6]arenes (2 with ten-butyl groups on the upper tim and 3 without tert-butyl groups) in unexpectedly high yields (80 - 91%). Combined studies of 2 and 3 by MM3 computation, X-ray analysis, and 1H NMR spectroscopy established that these calix[6]arenes feature a unique structure consisting of alternately-arranged three flattened mesitylene-linked phenyl units and three stand-up anisole units. Particularly, compound 2 possesses a closed ionophoric cavity: the upper hemisphere is closed by three ten-butyl groups of anisole units and the lower hemisphere is closed by a mesitylene cap and three anisole methoxy groups. The 1H NMR spectrum was scarcely changed at wide temperature range (30 ~ 130 °C), indicating that the structure is extremely rigidified. Both solvent extraction and spectroscopic studies established that this cavity shows the high selectivity toward Cs+ among alkali metal cations, the high affinity with Ag+, and the moderate affinity with RNH3+. Very surprisingly, the association-dissociation processes for 2 and cesium picrate was so slow that the rate could be followed by a conventional spectroscopic method. The thermodynamic parameters determined by kinetic studies disclosed that the major driving-force for Cs+ inclusion is the entropy term based on the desolvation.
View MoreXi'an Unique Electronic and Chemical Co., Ltd.
Contact:+86-029-88238008
Address:1703# B BUILDING WEST ELECTRONIC ZONE, XI'AN, CHINA
Wuxi Forest Biological Co.,Ltd
Contact:+86-510-81602300
Address:Room 317,Building D, No.159 middle Chengjiang Road,Jiangyin Wuxi city.
Taizhou Shengxing Chempharm Co.,Ltd
Contact:+86-576-88516600
Address:Yantou Chemical Zone Jiaojiang Taizhou Zhejiang China
Contact:+86 21 34123252
Address:14, 4580 Dushi, Shanghai, China
website:http://www.u-chemo.com
Contact:+86-21-61558312
Address:Dong Fang Road,
Doi:10.1002/ardp.19662990207
(1966)Doi:10.1002/ejoc.200300454
(2004)Doi:10.1016/S0040-4039(00)71329-3
(1976)Doi:10.1002/anie.201814373
(2019)Doi:10.1248/cpb.35.980
(1987)Doi:10.1021/ol027104u
(2002)