Large calixarenes

Since the research on the large calixarenes has been carried out in the laboratories of Gutsche and coworkers in the big state of Texas, these compounds have been colloquially designated as Texarenes . 

Mass spectra (see ref 1, pp. 83-84) continue to be useful in calixarene chemistry, primarily for the determination of the molecular weights of compounds such as the parent calixarenes with n > 8 and numerous other large calixarene-derived compounds e.g. a rigid cavity of nanosize dimensions ). Mass spectral deter-... 

For many years, it was thought that no calixarenes larger than n = 8 are formed in the one-step process. However, it is now known that calixarenes with sires well beyond this can be formed, extending to at least 20 aryl residues.Although several of the "large calixarenes n >8) can be obtained via base-induced condensation, an acid-catalyzed reaction provides a better source treatment of /7- crt-butylphenol with s-trioxane and /7-toluenesulfonic acid in CHCI3 solution produces an almost quantitative yield of a calixarene mixture that is richer in the large calixarenes than the product from base induction. 

Selective Functionalization The possibility to selectively append substituents at the endo rim is of prime interest for the synthesis of new hosts based on large calixarenes. In the selective modification of large calixarenes, the number of the possible partially substituted derivatives (16,28, and 46 for calix[7]-, -[8]-, and -[9] arenes, respectively) increases exponentially by increasing the number of phenol rings. Notwithstanding this inherent difficulty, the regioselective functionalizatiOTi at the endo rim of p-tert-butylcalix[7]arene C[7] has been obtained [21] through a... 

Coordination and Solid State Supramolecular Architectures Based on Large Calixarenes... 

In a systematic study, these large calixarene-DNA nanoparticles could be optimized. It was found, that longer alkyl tails lead to smaller nanoparticles with low polydispersity, promoted gene transfection and lowered cytotoxicity. On the other hand, the introduction of additional amine head groups only altered the stoichimetry of the calixarene-DNA complexes [75]. 

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