Cydodextrin polymer

An example of a STM manipulation on a jS-cydodextrin necklace has been given above (see Fig. 10.13) [75]. In further studies the same group further clarified the intramolecular structure of the cydodextrin polymer necklace with STM [158]. Head-to-head ( tail-to-tail ) to head-to-tail arrangement of the cydodextrin molecules were observed in the ratio (8 2). 

Harada, A. Design and Construction of Supramolecular Architectures Consisting of Cydodextrins and Polymers. Vol. 133, pp. 141-192. 

Cellulose and amylose are comprised of the same glucose subunits as the cydodextrins. In the case of cellulose, the glucose units are attached through 1,4-p-linkages resulting in a linear polymer. In the case of amylose, the 1,4-a-linkages, as are found in the cydodextrins, are thought to confer hdicity to the polymeric chain. 

Cyclodextrins. As indicated previously, the native cydodextrins, which are thermally stable, have been used extensively in liquid chromatographic chiral separations, but their utility in gc applications was hampered because their highly crystallinity and insolubility in most organic solvents made them difficult to formulate into age stationary phase. However, some functionalized cyclodextrins form viscous oils suitable forge stationary-phase coatings and have been used either neat or diluted in a polysiloxane polymer as chiral stationary phases for gc (119). Some of the derivatized cyclodextrins which have been adapted to gc phases are 3-O-acetyl-2,6-di-O-pentyl, 3-0-butyryl-2,6-di-O-pentyl,... 

Derivatives with decreased solubility in water have also been made. By crosslinking cydodextrins with epichlorohydrin, an insoluble polymer is formed. The polymeric cyclodextrin is able to form complexes with soluble compounds and remove them from solution. 

Cydodextrins can catalyze certain chemical reactions. Styrenesulfonate polymerization was accelerated in the presence of cyclodextrin, and the polymers had a higher molecular weight.109 Platinum-catalyzed hydroxylation reactions were accelerated in the presence of cyclodextrin.110... 

Many reports on the formation of supramolecular polymer in solution have been mentioned in this chapter. In particular, the interest in cydodextrin-based supra-... 

In the next larger cydodextrin, j8-CyD, aliphatic inserts are less popular, although the crystal structures of [3]pseudorotaxanes with aliphatic mono- [25] and diacids [18, 26, 27], diols [28], and bis-imidazolyl hydrocarbons [29] have been reported. j8-CyD/monocarboxylic acid complexes pack in channel structures and create supramolecular polymers, whereas 8-CyD/diacid complexes break the channel structure, contrary to what could be anticipated based on the propensity of acids to dimerize. With the wide y-CyD and aromatic guests, such as Congo Red [14] and ( )-stilbene [15] dimerization of the guest inside y-CyD is observed to form [4] and [3]pseudorotaxanes. Irradiation of crystalline complexes of the latter yielded syn-tetraphenylcyclobutane as a single isomer. 

Cydodextrin, p-Cydodexitin Hy oxypro- StaUlizer, UV food-grade polymers... 

Busche, B. J., Tonelli, A. E., and Balik, C. M. 2010. Rroperties of polystyrene/ polyjdimethyl siloxane) blends partially compatibilized with star polymers containing a y-cydodextrin core and polystyrene arms. Polymer 51 6013-6020. 

Keywords Cydodextrins complexation, ternary cyclodextrin complexes, lipophilic drugs, water-soluble polymers... 

Wdl-defmed 7-arm and 21-arm PNIPAAm star polymers possessing p-cydodextrin (P-CD) cores can be synthesized via the combination of ATRP and dick reactions. A series of alkynyl terminally functionalized PNIPAAm (alkyne-PNIPAAm) linear precursors with varying DP were synthesized via ATRP of NIPAAm using propargyl 2-chloropropionate as the initiator. The subsequent click reaaions of alkyne-PNIPAAm with azido-p-CD led to the facile preparation of well-defined 7-arm and 21-arm star polymers. 

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