确定六个在三碳桥的中心碳上具有一个或两个取代基的二苯并-14-冠-4衍生物的分子结构。该系列化合物包括三种冠醚醇,一种冠醚反式二醇和两种甲氧基冠醚化合物。这六个冠醚的晶体结构表明,由于氢键和空间相互作用,羟基取代基至少部分指向冠醚腔,并且在羟基之间形成了不寻常的分子内和分子间氢键网络质子和冠醚环的醚氧。另一方面,醚基或具有碳作为第一个原子的取代基远离聚醚环。符号的结构-(甲氧基)(甲基)二苯并-14-冠-4与符号-(羟基)(甲基)二苯并-14-冠-4在取代基取向和由其平面度引起的非常明显的变形方面都显着不同。前者为四冠醚氧。从13 C NMR测量中得出对溶液中对称-(甲氧基)(甲基)二苯并基14-冠4的异常构象的支持。冠醚醇是氢键结合的“构成元素”,它们参与强的,特定的和定向的分子间相互作用。
Synthesis of geminal-substituted, sterically congested, proton-ionizable dibenzo-14-crown-4, dibenzo-16-crown-5, dibenzo-19-crown-6 and dibenzo-22-crown-7 lariat ethers
作者:Dongmei Zhang、Xiaodong Liu、Sharon L. Williams、Chunkyung Park、Richard A. Bartsch
DOI:10.3998/ark.5550190.0011.704
日期:——
-16-crown-5, -19-crown-6 and -22-crown-7 lariatethers with different lipophilic geminal alkyl groups and different proton-ionizable groups are synthesized. For each lariatether platform, butyl, heptyl and decyl groups were incorporated as the geminal lipophilicgroups. Carboxylic acid, N-(trifluoromethane)sulfonylcarboxamide and sodium 3-propanesulfonate groups are incorporated on the platforms as proton-ionizable
Selective sorption and column concentration of alkali-metal cations by carboxylic acid resins with dibenzo-14-crown-4 subunits and their acyclic polyether analogs
作者:Takashi. Hayashita、Joung Hae. Lee、Matthew G. Hankins、Jong Chan. Lee、Jong Seung. Kim、John M. Knobeloch、Richard A. Bartsch
DOI:10.1021/ac00031a021
日期:1992.4.1
Alkall-metal cation sorption from aqueous and aqueous methanolic solutions and column concentration of alkall-metal cations from dilute aqueous solutions by carboxylic acid resins containing dibenzo-14-crown-4 units and their acyclic polyether analogues have been investigated. The crown ether carboxylic acid resins exhibit enhanced sorption selectivity over the acyclic polyether resins. Good sorption selectivity over the acyclic polyether resins. Good sorption selectivity for LI+ and Na+ was obtained with a cyclic polyether resin in which the carboxylic acid group is positioned over the crown either ring. For column concentration of alkali-metal cations from dilute aqueous solutions, gradient elution of the sorbed metal ions from the resin with the carboxylic acid group positioned over the crown either cavity gave selective column concentration of Li+ and Na+.