Calix aryl esters

Thus, it has been shown that calix[4]aryl esters exhibit remarkably high selectivity toward Na [11-14]. This is attributable to the inner size of the ionophoric cavity composed of four 0CH2C=0 groups, which is comparable to the ion size of Na, and to the cone conformation that is firmly constructed on the rigid ca-lix[4]arene platform (Scheme 2). 

In another work, ionophoric 6/i-calix[4]aryl esters in which the lower edges confront each other were syn-... 

Widening the opposite side of a calixarene upon complexation of small cations to the oxygen atoms of a calixarene lower riin leads to the positive heterotropic allosteric effectin the inclusion o/[60]fullerene in a cage molecule 14 (Fig. 4) derived from two calix[3]aryl esters by complexation of their pyridine groups with Pd(II). " ... 

A number of other types of calixarene esters are known, including the aryl-sulfonates (often used to establish the calix[4]arenes in the cone conforma-tion ), phosphates (often used as intermediates in the replacement of the OH groups with and phosphonates. ... 

Tanaka M, Kobayashi T, Yamashoji Y, et al. (1991) Polymer membrane sodium-selective electrodes based on calix[4]aryl decyl ester. Analytical Sciences 7 817-818. 

B di-tert-butylated calix[4]aryl decyl ester [5]. C p-t-octyl calix[4]aryl decyl ester [6,21],... 

Recently, Shinkai et al [20] studied PVC membrane electrodes based on the calix[4]arene derivative and reported that the p-t rt-octyl-calix[4]aryl tetraethyl ester-FPNPE system electrode allowed high Na" selectivity. The Na selectivity coefficient being 3.1 [20], though its value was not evaluated by a fixed interference method (FIM). Its excellent Na selectivity compared with those of our similar derivative, p-rerr-octylcalix[4]aryl tetradecyl ester [6,21], is probably derived from the introduction of shorter alkyl groups such as the ethyl ester and tert-oct group into the upper rim moiety to produce lipophilicity, as already mentioned. 

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