Monobenzo-18-crown

An alternative copolymerization is illustrated by the method of Blasius. In this preparation, a phenol-formaldehyde (novolac) type system is formed. Monobenzo-18-crown-6, for example, is treated with a phenol (or alkylated aromatic like xylene) and formaldehyde in the presence of acid. As expected for this type of reaction, a highly crosslinked resin results. The method is illustrated in Eq. (6.23). It should also be noted that the additional aromatic can be left out and a crown-formaldehyde copolymer can be prepared in analogy to (6.22). ... 

Although fullerenes have frequently been used as a building block in the preparation of supramolecular systems, recently a few examples have been reported in which hydrogen-bonding motifs dictate the ensemble arrangement. In one of the first examples, the formation of a self-assembled monolayer (SAM), was carried out by self-assembly of fullerenes, endowed with a monobenzo 18-crown-6 ether moiety on a gold surface (vide infra) ... 

Polystyrene with Monobenzo crown and Substitution reaction of Blasius et al. 

Silica gel Monobenzo crown Substitution reaction of Waddell, Leyden... 

Monovinyldibenzo-18-crown-6 may be prepared by utilizing a preformed two-armed, monobenzo precursor as illustrated in Eq. (6.26). Such precursors are discussed in Chap. 3. With the two-armed precursor in hand, crown formation can be accomplished using acetylcatechol just as illustrated in Eq. (6.25), above. 

Casnati, A., Sansone, F., Dozol, J.F. 2001. New calyx[4]arene-monobenzo- and dibenzo-crown-6 as cesium selective ionophores in the radioactive waste treatment Synthesis, complexation and extraction properties. J. Inch Phenom. Macro. Chem, 41 (1-4) 193-200. 

It has been established that alkali metal cations exactly fitting the size of the crown ether ring form a 1 1 complex whereas those that have larger cation radii form a 1 2 sandwich complex. This view was clearly substantiated by using bis(crown ethers). For instance, Kimura et al. [10] reported that the maleate diester of monobenzo-15-crown-5 ((Z)-form) extracts K+ from the aqueous phase... 

Polymeric crown ethers are prepared by condensation, polymerization, or substitution [37]. Above all, condensation polymers based on monobenzo- and dibenzocrown ethers are immobilized on the surface of a solid substrate, and are used in chromatographic applications. They are distinguished by chemical and thermal stability and exhibit a relatively high capacity. Modified and non-modified silicas are used preferentially as support materials. 

A listing of benzoaza-crown macrocycles follows. The tables are organized by monobenzo units (Tables 8.1-8.3), dibenzo units (Tables 8.4-8.10), polybenzo or naphtho units (Table 8.11), ring size (each table) and number of ring nitrogen atoms (each table). 

Bribre, K.M. Detellier, C. Metal interchange of crown ether-alkali metal cation complexes in solution. Li Nuclear magnetic resonance study of the exchange kinetics of lithium 15-crown-5 and lithium monobenzo-15-crown-5 in nitromethane. J. Phys. Chem. 1992. 96 (5), 2185-2189. 

Monobenzo- and dibenzocrown ethers are chlorosulfonated by reaction with a large excess of chlorosulfonic acid. Monobenzo-12-crown-4, -15-crown-5 and -18-crown-6-ethers, when treated dropwise with chlorosulfonic acid (10 equivalents) in chloroform solution at —10 to —5 C and the reaction mixture left at RT (five to six hours), gave the corresponding sulfonyl chlorides in 65-75% yield. For instance, monobenzo-12-crown-4-ether 498 afforded the chlorosulfonyl derivative 499. The orientation of sulfonation is, as expected, p to the electron-donating oxygen atom. 

---