Cyclodextrin calixarene

Development of ditopic receptors 58 for both an anion and a cation is a logical extension [19b]. It should be stressed that the recognition by cyclodextrins, calixarenes, hemicarcerands, and many other systems does not involve specific recognition sites, whereas tetrahedral recognition by 53 and 54, the adenine 56 selective binding, and multiple recognition like the one shown in formula 59 [20] require the presence of specific sites in receptor capable of directional interactions. 

The ESIPT of 2-(2 -hydroxyphenyl)-4-methyloxazole (HPMO) (27) has been explored by Douhal and co-workers [166] for its probe characteristics in a variety of organized media which include cyclodextrin, calixarene, micelle, and HSA. The incorporation of HPMO into hydrophobic cavities in an aqueous medium involves the rupture of its intermolecular hydrogen bond to water and formation of an intramolecular hydrogen bond in the sequestered molecule. Upon excitation (280-330 nm) of this entity, a fast intramolecular proton-transfer reaction of the excited state produces a phototautomer (28), the fluorescence of which (Xm = 450 170 nm) shows a largely Stokes-shifted band. Because of the existence of a twisting motion around the C2—C bond of this phototautomer, the absorption and emission properties of the probe depend on the size of the host cav-... 

Instead of cyclodextrin, calixarene has also been used as the monolayerforming component in sensor preparation. In the example shown in Fig. 4.41, a self-assembled monolayer of calixarene was immobilized on an electrode of a quartz crystal microbalance. The quartz crystal microbalance is a masssensing device capable of nanogram-level precision (see Chap. 5). When the monolayer-covered microbalance was exposed to guest gas, the guest bonding... 

Abstract New applications of ID and 2D solid state (SS) NMR spectroscopy in structural studies of inclusion complexes (ICs) formed by organic host lattices (cyclodextrins, calixarenes, cyclophosphazenes, and fullerenes) are described. Each section of the review gives short characteristics of host molecules and recent applications of SS NMR. Less common systems, which are interesting as models for SS NMR studies, (bis[6-0,6-0 -(l,2 3,4-diiso-propylidene-a-D-galactopyranosyl) thiophosphoryl] disulfide (DGTD) and 1,2-dichloro-ethane/tris(5-acetyl-3-thienyl) methane (TATM)), are also discussed. 

Phosphorus-containing chiral cyclodextrins, calixarenes, and cyclophanes 06COC2307. 

The search for artificial host mimics possessing specific weak interaction and complexation properties to ions and neutral molecules has inspired scientists to work with great effort during the past several years and much success can be reported. Different subareas of research related to this matter have developed (crown chemistry, cyclodextrins, calixarenes etc.). They are partly a subject of former volumes of this series (cf. Top. Curr. Chem. 98, 101,121,123,125,128,132, and 136). 

It was demonstrated that the induced-fit concept of the interaction between an enzyme and a substrate was introduced from biological processes to supramolecular systems for explaining the molecular-binding behavior of artificial receptors, including crown ethers, cyclodextrins. calixarenes, porphyrins, etc. The induced-fit mechanism was utilized to explore the binding behavior of ions and molecules, and was adopted to accurately describe... 

Hofmann-type clathrates Werner clathrates clathrate hydrates inclusion compounds of urea, thiourea, and selenourea cyclodextrins calixarenes gossypol hexa-hosts hydroquinone phenol and Dianin s compounds graphite intercalates natural and pillared clays and others. Such studies contributed to the birth of supramolecular chemistry, with relevance to a new understanding of the world of materials that was emphasized with a Nobel Prize. 

The use of SAMs as a facile way to attach other functionalities to the electrode surface has been exploited in the development of chemical sensors (44, 45). Functionalities presented at the electrode easily modulate the selectivity of the electrode surface for an analyte of interest. Cyclodextrins, calixarenes, and other molecules with size and shape specificity... 

Thus, macrocyclic amphiphiles are reviewed by Huang et al. with respect to cyclodextrins, calixarenes, cucurbiturils and pillararenes [1]. Similarly, Ma and Zhao present biomedical applications of supramolecular systems based on host-guest interactions, with a focus on cyclodextrins, calixarenes and cucurbiturils [2]. Sansone et al. published a review on calixarenes as multivalent ligands for biomolecular recognition [3]. 

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