Lower rim substitution

Yordanov, A. T. Roundhill, D. M. Electronic absorption spectroscopy for the investigation of the solution binding of gold, palladium, mercury and silver salts to the lower rim substituted calix[4]arenes 25,26,27,28-(2-N,N-dimethyl-dithiocarbamoylethoxy)calix[4]arene and 25,26,27,28-(2-methylthioethoxy)calix[4]arene. Inorg. Chim. Acta 1998, 270, 216-220. 

Beer, P. D., Gale, P. A., Chen, Z., Drew, M. G. B., New bis- and tris-ferrocenoyl and tris-benzoyl lower-rim substituted calix[5]arene esters Synthesis, electrochemistry and X-ray crystal structures. Supramol. Chem. 1996, 7, 241-255. 

Alkylation of the lower rim substitution with carbonyl-containing groups (101) has produced probably the most widely studied of the calixarene-based ionophores. These derivatives have been studied predominantly as ionophores for hard metal cations, and can form complexes of comparable stability to those of the cryptands in some cases. Such calixarenes have found applications as ionophores in ion selective electrodes. ... 

Lower rim substitution can also be used to link cahxarene molecules. An elegant example was produced by linking two calix[4]arenes with four ethylene bridges to produce what was termed as a calix[4]tube (102). The synthesis was templated by the potassium ion, and the product was found to bind this cation selectively. 

Finally, both upper and lower rim substitution have been used to produce a class of macrocycles referred to as calixarene-crown ethers, or calixcrowns. One simple example is shown here (103). These receptors combine characteristics of the crown ethers and calixarenes, and have been intensively studied for metal ion extraction, in particular, for the removal of cesium from nuclear waste. ... 

Figure 3.20 Expected conformer distribution for Lower rim substituted oxacalix[3]arenes...

The earliest examples of lower rim-substituted calixarenes investigated for their complexation properties are the ethyleneoxy compounds which... 

Fig. 2.16 Inherent chirality of calixarenes introduced by (a, b) lower rim substitution (c, d) spacial alignment (e) directional bridging...

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