Cyclic Polymers Obtained by the CuAAC Click Reaction

Cyclic Polymers Obtained by the CuAAC Click Reaction 

Cyclic polymers represent a special class of macromolecules among the various possible polymeric architectures. Because of the absence of chain ends in cyclic polymers, different chain dynamics can strongly influence physical properties compared with linear analogs of the same mass [95]. Recently, therefore, large cyclic polymers have emerged from the realm of scientific curiosities to that of potentially useful macromolecular architectures for a variety of functional applications [96-99]. By virtue of the lUPAC definition [1], cyclic polymers can be considered as macrocycles. Polymers with (small or large) cyclic repeating units within the macromolecular backbone, cyclopolymers, have been known for some time [100-104], and they must not be assimilated to cyclic polymers. 

Sequential click strategies were utihzed by Zhang, Cheng, and coworkers to precisely construct new surfactants based on polyhedral oligomeric silsesquiox-ane (POSS), tethering cychc polymers [109]. The general synthetic approach involves different types of click chemistries sequentially performed strain-promoted azide-alkyne cycloaddition (SPAAC), CuAAC for POSS—polymer conjugation, and thiol-ene reactions for POSS surface functionalization. 

(1988) Angew. Chem. Int Ed. Engl, 27, 1009-1020. lUPAC http //goldbook.iupac.org/ M03662.html (accessed on June 2015). Pedersen, C.J. (1967) /. Am. Chem. Soc., 89, 7017-7036. 

Vogtle, F., and Burrell, A.K. (1992) Macrocycles, Springer-Verlag. Lehn, J.-M. (1995) Supramolecular Chemistry. Concepts and Perspectives, Wiley-VCH Verlag GmbH. 

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