Inclusion Compounds of the Calixarenes

Asfari, Z., Bohmer, V., Harrowfleld, J. and Vicens, J. (eds.), Calix 2001, Kluwer, Dordrecht, 2002. 

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The calixarenes have a flexible or rigid cavity, resp., which can be shaped to some extent. Some inclusion compounds in the solid state have bren described, but the low solubility in water did not allow applications in respect to an enzyme mimick as yet. Host/guest interactions in solution according to studies of Gutsche et al. seem to occur in some cases, but are weak. Shinkai and coworkers seem recently to have overcome parts of these problems by incorporation of sulfonic add groups in this skeleton (72 and 73). 

For a time one managed by choosing new descriptions and used intricate contractions and modifications of the available terms Some examples being clathrate complex, clathrate hydrate, hydrocarbon clathrate, gas hydrate, interlamellar sorbent, molecular compoimd, addition compound, loose addition complex, cascade complex, lock-and-key complex, super molecular complex, molecular complex associate, tweezer molecule complex, soccer molecule complex, hexapus molecule complex, octopus molecule complex as well as complexes or inclusion compounds of spherands, sepulchrands, coronands, cyclidenes, cryptands, cryptophanes, calixarenes, cucurbit-uril, annelides etc. 

Study of the inclusion behaviors of the cavity of many commonly known macrocyclic receptors like calixarenes, cyclodextrins and cyclic oligopeptides draws considerable interest in supramolecular chemistry. However, the construction of inclusion compounds using self-assembly of... 

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 t-butyl-calix[9]arene co-crystaUizes with o-carborane, cyclohexane and water. It does not form inclusion complexes with either of these compounds. The conformation of the calixarene is basically similar to the rosette one but it is highly folded (Fig. 38.30a). In case of the t-butyl-calix[10]arene inclusion of one acetone and one toluene molecule inside the macrocyclic ring occurs and two other toluene molecules take part in additive complex formation (Fig. 38.30b). In this... 

Noteworthy also is the reaction between L42 and Cul in the presence of KI. The crystal structure determination reveals the formation of hitherto unknown exocyclic Cu g2- clusters, which are linked by L42 to generate a polymeric ID array of composition pC2(Cu4I6)L42]n 42". Within the crown ether cavities of L42, two potassium ions are trapped in an endocyclic manner. Also, upon inclusion of the K+ ions the crown ring shrinks leading to opening of opposite aromatic rings in the host calixarene unit, a rare behavior for this class of compound.162... 

Much interest has centred on the branch of cyclophanes known as calixarenes. They are polyphenol systems that can act as hosts in the formation of inclusion compounds, where a small guest molecule resides completely in a cavity within a single host they are cone-shaped cavitands . Several accounts have appeared of their history. The discovery by Baeyer of a formaldehyde/phenol resin led to Bakelite and to the work of A. Zincke and E. Ziegler, who gave to the first oligomer a tetrameric structure of a calix[4]arene. Later syntheses by Gutsche (1978) led to calixarenes with 4, 6 or 8 phenol residues.107-109... 

G. D. Andreetti, A. Pochini, R. Ungaro, Molecular Inclusion in Functionalized Macrocycles. 6. The Crystal and Molecular-Structures of the Calix[4]arene from Para-(l,l,3,3-Tetramethylbutyl)Phenol and Its 1-1 Complex with Toluene. J. Chem. Soc. Perkin Trans II 1983, 1773-1779 G. D. Andreetti, F. Ugazzoli, in Calixarenes A Versatile Class ofMacrocyclic Compounds, J. Vicens and V. Bohmer, eds. Kluwer, Dordrecht, 1991. 

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