Supramolecular hosts cyclodextrins

The main supramolecular self-assembled species involved in analytical chemistry are micelles (direct and reversed), microemulsions (oil/water and water/oil), liposomes, and vesicles, Langmuir-Blodgett films composed of diphilic surfactant molecules or ions. They can form in aqueous, nonaqueous liquid media and on the surface. The other species involved in supramolecular analytical chemistry are molecules-receptors such as calixarenes, cyclodextrins, cyclophanes, cyclopeptides, crown ethers etc. Furthermore, new supramolecular host-guest systems arise due to analytical reaction or process. 

The supramolecular (host) system is viewed as a confined space in which the probes and/or quenchers are located. Assumptions have to be made regarding the availability of complexation sites in each system. For host-guest complexes, such as cyclodextrins, stoichiometries of complexation are assumed or determined experimentally [50,51]. In the case of self-assembled systems, such as micelles or vesicles, the most common assumption is that at low probe/mi-celle ratios the distribution of probes follows a Poisson distribution [30]. This means that the probability of encountering a molecule in a particular micelle is independent of how many molecules are already in that micelle. 

In this paper, a study of supramolecular host-guest interactions between small molecules is reported. Interactions between p-cyclodextrin (P-CD) receptors in highly ordered self-assembled monolayers (SAMs) on Au(lll) and ferrocene moieties immobilized on AFM tips were measured in dynamic force spectroscopy measurements [11]. 

Catalyst Per-6-amino-p-cyclodextrin (per-6-ABCD) — acts as a supramolecular host and a reusable solid base catalyst... 

Dioxirane-based site-selective oxidation of the terminal over the internal tertiary C-H bond of 3,7-dimethyloctyl esters was achieved in water with -cyclodextrin as the supramolecular host. In aqueous medium, -cyclodexU in selectively enhanced the C-H bond oxidation of ciunene in a mixture of cumene and ethyl benzene also. ... 

In principle, there are four basic strategies to compensate for the repulsive effects between the hydrophobic fullerene surface and water (a) encapsulation in the internal hydrophobic moiety of water-soluble hosts like cyclodextrins (Andersson et al., 1992 Murthy and Geckeler, 2001), calixarenes (Kunsagi-Mate et al., 2004) or cyclotriveratrylenes (Rio and Nierengarten, 2002) (b) supramolecular or covalent incorporation of fullerenes or derivatives into water-soluble polymers (Giacalone and Martin, 2006) or biomolecules like proteins (Pellarini et al., 2001 Yang et al., 2007) (c) suspension with the aid of appropriate surfactants and (d) direct exohe-dral functionalization in order to introduce hydrophilic moieties. 

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