Cryptands calixarenes

Amphiphilic macrocyclic host molecules have been investigated for many years. Among others, it is known that amphiphilic crown ethers, " cryptands, calixarenes, cyclodextrins, and curcubitnrils can form bilayer vesicles in aqueous solution. However, the host-guest chemistry of such host vesicles remained largely unexplored for many years. Darcy and Ravoo prepared bilayer vesicles composed entirely of amphiphilic cyclodextrin host molecules. These vesicles have a membrane that displays a high density of embedded host molecules that bind hydrophobic guest molecules such as f-butylbenzyl and adamantane derivatives. The characteristic size-selective inclusion behavior of the cyclodextrins is maintained, even when the host molecules are embedded in a hydrophobic... 

S-donor macrocycles are typically sulfur-substituted crown ethers. The mixed donor macrocycles include those with N/S, S/0, N/O, and N/S/O combinations. Calixarenes and resorcinarenes are most often 0-donors, but may contain various functional groups and thus be classified here as mixed donor macrocycles. The macrocycles most widely used in IC and liquid membrane separations have been the crown ethers, nitrogen-substituted crown ethers, cyclen, cyclam, cryptands, calixarenes, resorcinarenes, and CDs. 

Applications of ferrocenes are numerous,in particular with the use of ferrocenyl phosphines, including chiral ones (see for insance the aminophosphine below), as ligands for catalysis. l,l -bis(diphenylphosphino)ferrocene (dppf, below) is the best known ferrocenyl-based ligand in the catalysis of most classic reactions, and its chemistry and uses are prolific. The redox property of ferrocene has been used to attach it to macrocycles (below), cryptands, calixarenes and other endo-receptors for sensing, a chemistry beautifully developed by Paul Beer at Oxford,... 

A new type of calixarene-capped calixpyrrole (9) has been generated (32 %) in one-step from p-fe/t-butylcalix[4]arene tetramethylketone as the template <96TL7881>. A cylindrical calix[4]-fois-cryptand, in which the central calix[4]arene possesses two 1,3-altemating diaza-tetraoxa macrocycles on each face, has been synthesized <96TL8747>. A series of substituted l,4-(2,6-pyridino)-bridged calix[6]arenes has prepared and studied <96LA1367>. 

In addition to macrocyclic hosts discussed above, many other molecules capable of selective complexation have been synthesized. They belong to so-called macrocyclic chemistry [30] encompassing crown ethers discussed in this Chapter, cryptands 61-63 [21], spherands 70 [31], cyclic polyamines 71 [32], calixarenes 18 [5], and other cyclophane cages such as 72 [33] to name but a few. Hemicarcerand 5 [2b] discussed in Chapter 1 and Section 7.3 also belongs to this domain. Typical macrocyclic host molecules are presented in Chapter 7. 

Various approaches have been taken to the synthesis of effective luminescent materials, using a variety of large encapsulating antenna-containing ligands, including podands, calixarenes, macrocycles, and macrobicycles (cryptands). These have been divided into acyclic (sub-section A) and cyclic (sub-section B). Representative ligands and complexes will be presented and discussed. 

Compare and contrast the properties of the following classes of host molecule. Include in your answer information on selectivity, solubility and binding kinetics (a) naturally occurring ionophores (b) podands (c) corands (e) lariat ethers (f) cryptands (g) calixarenes and (h) spherands. You may find it helpful to present the information in the form of a comparative table. 

Dinitroazobenzene was used as the fluorescent residue in a chiral receptor molecule that incorporated both a crown ether and calixarene, the structure of which is shown in Figure 15. Formally, this comprises a ditopic cryptand but such a simple nomenclature is clearly inadequate <2004CH1174>. 

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. ... 

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