Calix arenes, receptor molecules based

Receptor Molecules Based on Calix[5]- and Calix[6]arenes... 

Z Brzozka, B Lammennk, D N Remhoudt, E Ghidim, and R Ungaro, Transduction of selective recogmtion by preorgamzed lonophores, K+ selectivity of the different l,3-diethoxycalix[4]arene crown ether conformers, J Chem Soc Perkin Trans 2 (1993) 1037-1040 J A J Brumnk, J R Haak, J G Bomer, D N Remhoudt, M A McKervey, and S J Hams, Chemically modified field-effect transistors, a sodium ion selective sensor based on calix[4]arene receptor molecules, Chm Acta, 254 (1991) 75-80... 

Calix[ ]arenes are a family of macrocycles prepared by condensation reactions between n /v/ra-substituted phenols and n formaldehyde molecules under either base or acid catalysis. Different sizes of the macrocycles can be obtained (n = 4-20) (Stewart and Gutsche, 1999) depending on the exact experimental conditions, which were mastered in the 1960 s (Gutsche, 1998), but the most common receptors are those with n =4,6,8 (macrocycles with an odd number of phenol units are more difficult to synthesize). We use here the simplified nomenclature in which the number of phenolic units is indicated between square brackets and para substituents are listed first.4 Calixarenes, which can be easily derivatized both on the para positions of the phenolic units and on the hydroxyl groups, have been primarily developed for catalytic processes and as biomimics, but it was soon realized that they can also easily encapsulate metal ions and the first complexes with d-transition metal ions were isolated in the mid-1980 s (Olmstead et al., 1985). Jack Harrowfield characterized the first lanthanide complex with a calixarene in 1987, a bimetallic europium complex with p-terf-butylcalix[8]arene (Furphy etal., 1987). 

Until now, only a restricted number of photopolymerizable calix[4]arene-based receptor molecules are known. Calix[4]arene 42 showed to be selective for Na ions in the presence of different interfering ions [29]. More recently, we also synthesized... 

Metal-based nanoparticles decorated with calix[4]arene receptors to sense polycyclic aromatic hydrocarbons (PAHs) have been developed by Sanchez-Cortes [ 145]. Each combination of host and PAH (pyrene, triphenylene, benzo[c] phenanthrene, coronene) gave a different signature in their surface-enhanced Raman scattering spectra, thus offering valuable information on the interaction between the calix[4]arene receptors and the PAH molecules. 

In this article we will illustrate our new strategy with a few examples of receptor molecules composed of calix[4]arenes in combination with several other building blocks that exhibit unique complexation properties. Moreover we have found new routes for the selective introduction of functional groups both in calix[4]arenes and resorcinarenes. One of these methods comprises the key step in the synthesis of calix[4]arene-based carcerands in which guest molecules are permanently encapsulated in an asymmetric environment. Finally, the first example of a holand, a molecule with a large rigid cavity of nanosize dimensions, will be described. 

Following up on their previous work [73] with covalently-linked double calix[5] arenes, Fukazawa and coworkers [74] reported the fullerene complexation of other related double calix[5]arene receptors in a series of studies published in 2001-2010. A fullerene (Fig. 33.34) receptor which they produced was based on a silver-cation assisted self-assembled pair of upper-rim mono-2,2 -bispyridyl-functionalized tetra-p-methylcalix[5]arenes 49. The cavity thus produced formed quaternary complexes C6o 49 Ag 49 and C7o 49 Ag 49 with the respective fullerenes in 1,1,2,2-tetrachloroethane ( TCE ) and which were established by using ESI MS. The relative intensities of the mass signals also suggested a preference for Ceo over C70. Later, these authors prepared a double calix[5]arene derivative 50 which was based upon linking two molecules of 49 covalently via their bipyridines. As measured by UV-Vis titration, treatment of Cgo with the complex of 50 with [Cu... 

Abstract Calix[n]arenes represent a well-known family of macrocyclic molecules with a broad range of potential applications in many branches of supramolecular chemistry. Because of their preorganisation, calix[n] arenes are frequently used as building blocks and molecular scaffolds in the construction of more elaborate systems, such as artificial enzyme biomimetics and receptors. This review is focused on the recent development of calixarene-based anion receptors. 

Another family of calixarene-based ditopic receptors are the l,3-calix[4]arene-Z w(crown ethers), where the calixarene is locked into the 1,3-alternate conformation, and substrate binding normally occurs at the crown ether loops. These may form mononuclear or dinuclear complexes with alkali inetal cations, or may bind neutral guest molecules. The unsymmetrical 1.3-alternate calix[4]ar-ene-l,3-crown-6 2,4-(l,2-phenylene)-crown-6 forms a 1 1 complex with Cs. The crystal structure shows that the cation is bound only within the adapted phenylene-crown-6 loop, and a molecule of acetonitrile is bound within the unmodified crown-ether loop. ... 

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