Calixarene and dendrimer

Calixarenes and dendrimers (see above) have been employed as a matrix for negative imaging through condensation [374]. 

Presence of intergrown guest structures like calixarenes and dendrimers. 

Similarly, a series of hydroxy-terminated poly(ether) dendrimers, 35, with a single carborane nucleus at their core, were observed to have water solubilities comparable to that of chloroacetic acid, or D,L-valine. Again this is in direct contrast to the starting carborane nucleus which is insoluble in aqueous solutions and permitted the use of 35 in neutron capture therapy. Similar effects have also been observed with dendrimers containing calixarenes [66] and porphyrins [67] as the central units. 

Supramolecnlar derivatives containing crown ether [228], calixarenes [264, 265] or dendrimers [267, 279] have been synthesized with the precursors shown in Table 4.10. Fullerene-flavonoid [268] or the fuUerene glycoconjugate [258] derived from 237 and 235, respectively, are expected to show biological activity. 

Such specific ligand systems as catenanes [968], calixarenes [969], fullerenes [970a,b], and cyclodextrines [971], and functionalized dendrimers [972a-d] are of great interest. Thus, on the basis of fullerenes C60 and C80 were obtained metal-cyclo-pentadienyl and metal-carbonylcyclopentadienyl compounds with rj1 - and r 5-coordination bonds [970b]. 

Besides these classical aromatics and polyaromatic hydrocarbons, other very important classes or arene molecules are porphyrins [60, 61], phthalocyanins [61, 62], porphycens [63], calixarenes [64], resorcarenes [64], cydophanes [47], dendrimers [65], elementa-arenes [66], organometallic arene (hexahapto) [67], benzyne (dihapto), and aryl- and benzyl (monohapto) complexes [68], inorganic pyridine and polypyridine complexes [69], fullerenes [70, 71], and... 

Several artificial receptors such as crown ethers, cyclodextrins, cyclophanes, and calixarenes find applications in molecular recognitions processes. Further, there have been several research publications that focus on computational design and analysis of recognition properties of artificial receptors such as cyclodextrins,15 dendrimers,610 crown ethers,1112 and calixarenes.13 5 Typically computational... 

Miscellaneous Reactions. Wittig technology has been used to prepare ylide-, phosphate-, phosphite- and phosphinate-terminated dendrimers, and calixarenes bearing pyridyl podands on their upper rim 7°... 

Other photoisomerizable molecules including azobenzene-capped /1-cyclodex-trins, dendrimers, aza-crown and calixarene compounds have been reported [14,160,161] and, though they are not used for studying biomolecules, they open up new perspectives in the field of supramolecular chemistry and help to understand basic concepts that have been validated in biochemistry. 

Often symmetry operations cannot be used in a simple way to classify chiral forms because, e.g., the molecule consists of a number of conformations. Therefore, independent of the symmetry considerations, a chemical approach to describe chiral molecules has been introduced by the use of structural elements such as chiral centers, chiral axis, and chiral planes. Examples for a chiral center are the asymmetric carbon atom, i.e., a carbon atom with four different substituents or the asymmetric nitrogen atom where a free electron pair can be one of the four different substituents. A chiral axis exists with a biphenyl (Figure 3.2) and chiral planes are found with cyclo-phane structures [17]. Chiral elements were introduced originally to classify the absolute configuration of molecules within the R, S nomenclature [16]. In cases where the molecules are chiral as a whole, so-called inherent dissymmetric molecules, special names have often been introduced atropiso-mers, i.e., molecules with hindered rotation about a helical molecules [18], calixarenes, cyclophanes [17], dendrimers [19], and others [20]. 

The incapsulation of light metals inside the nanopores or nanocavities of MOFs or inside the calixarene baskets, or inside the branches of the dendrimer will result in the hydrogen spill-over and further enhancement of the capacity ... 

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