Calixarene probe

Sabbatini, N. Guardigli, M. Manet, I. Ziessel, R. Luminescent probes [involving calixarenes], Calixarenes 2001 Ed. Asfari, Z. Kluwer Academic Publishers, 2001. 

If a highly polarizable group is introduced into a receptor molecule, substrate binding should cause substantial perturbations, so that the recognition event would be converted into a non-linear optical signal. Such recognition-dependent nonlinear optical probes may be derived for instance from polyenes such as those shown in Figure 20, from inclusion complexes [8.94a] or from donor-acceptor calixarenes [8.94b]. 

HPNPP (101) was also used to probe the catalytic ability of zinc- and copper-containing calix[4]arenes that carried two or three [12]ane-N3 macrocycles on their upper rim. Cooperativity was found between the catalytically active metal complexes during phosphodiester transesterification provided that they were adjacent to each other, i.e. on proximal positions of the calixarene rim, whereas those on opposite... 

Although fluorescent calixarenes would be an appropriate section herein, especially as regards nuclear applications, the reader is referred to the recent and exhaustive review Calixarene-derived Fluorescent Probes. 85... 

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-... 

Reinhoudt et al. have coupled 3-CD with a probe-modified calix[4]arene to detect neutral analytes in aqueous solutions [160,161], The fluorescence capabilities of the multireceptor chemosensor arise from dansyl (26) and 2-naphthylamine (27) fluorophores attached to the rim of the calixarene. Like... 

Both lower rim and upper rim substitutions have been used to modify the coordination strength of the calixarenes and the properties of the resulting edifices. We shall only give a few examples here, with an emphasis on the efforts aimed at designing efficient luminescent probes and extraction agents. 

Fig. 4.53. Substituted calixarenes for lanthanide-containing luminescent probes.

The calix[4]arene-based diphosphine (119) (R = Me, Pb, Ph R = Pb) on reaction with [Rh(/r-Cl)(COD)]2 and then TlPFg forms the dinuclear species (120). These were tested as catalysts for hex-l-ene hydroformylation (see Carbonylation Processes by Homogeneous Catalysis) and that with R = Ph was best, but the performance was not better than extant systems and no special role for the calixarene moieties could be discerned. Several papers have used DFT calculations as part of QM/MM studies (see Molecular Orbital Theory) to probe the course of the hydroformylation process (see Carbonylation Processes... 

The chemical behavior of clays is also mimicked by the title complexes in two respects the presence of cation-exhange capabilities and the reduced water content in the ammonium salt [20]. Currently, other similarities between clays and the water-soluble calixarenes are being probed. In particular, the size- and polarity-selective cavity of the calix[4]arene sulfonates is finding utility in the separation of organic substances, cations, anions, and neutral molecules, from aqueous feed streams. 

Effect of Calixarenes on the Fluorescence of Probe Pyrene within Micellar [C,mim][CI]... 

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