摘要:
IntroductionCMethylcalix[4]resorcinarene1is a resorcinolbased macrocycle which commonly assumes a bowlshaped conformation in organic media.1The curved architecture of such calix[4]resorcinarenes, and the phenolic groups on the upper rim, render them ideal for both the inclusion of appropriately sized and shaped species2,3as well as interaction with metal ions4or hydrogenbonding species at the periphery.5A range of assemblies with defined interiors and interesting extended structures have been obtained usingCmethylcalix[4]resorcinarene. For example, in the presence of 4,4′bipyridyl, capsules based on two calix[4]resorcinarene molecules result,6as is the case in the presence of propan2ol.7These structures are both assembled through hydrogen bonding. Similarly, hydrogenbonding interactions with water molecules are instrumental in the assembly ofCmethylcalix[4]resorcinarene into a spherical hexamer.8However, its assembly in the presence of curved molecules for which there is complementary size and shape with the cavity has not been explored. Suitable guests include 18crown62and [2.2.2]cryptand (shown as its Na+complex3), and in this context we note that the similarly bowlshapedpsulfonatocalix[4]arene, and a resorcinarenebased cavitand, are capable of forming host–guest complexes with 18crown69–13and [2.2.2]cryptand14respectively. In the case of 18crown6 withpsulfonatocalix[4]arene a range of structural types have been observed, including dimeric capsules,9,10,11claylike bilayers12and helices.13Herein we establish that a 1∶2.5 assembly can be obtained from a mixture of the calix[4]resorcinarene and crown ether, and that a 1∶1 assembly forms from the monodeprotonated calix[4]resorcinarene and the cryptand as its sodium complex.
ISSN:1466-8033
DOI:10.1039/b100578m
出版商:RSC
年代:2001
数据来源: RSC