Polymers, with threaded rings

While the PDIs of the REMP macrocycles are higher than those typically reported for the ring-closure approach, the molecular weights obtained are by far the highest reported to date for a cyclic polymer synthesis. The catalyst design optimization has yielded improved polymerization catalysts, and promises to broaden the versatility of this route. For example, by using a dendronized monomer, Grubbs and coworkers have demonstrated the synthesis of dendronized cycHc polymers and confirmed their cyclic structure with AFM [59], and have also synthesized cycHc polymers with threaded rotaxanes [60]. 

Crosslinking of a-CD with epichlorohydrin in aqueous solution under well controlled conditions furnished hyperbranched water-soluble a-CD polymers [96,97]. On the other hand, template directed crosslinking of a-CD, threaded on PEG, gave rise to linear CD polymers with two to three bridges between every two neighboring rings, or so-called molecular tubes, as shown in Fig. 2 [98-101],... 

Even Staudinger (89) assigned cyclic structures to poly-indene and polystyrene. He visualized that these polymers would be stretched out into double threads with closed ends in which the two halves of the ring would lie parallel. He called this his "bifilar" hypothesis. 

Potential use of complexes of y - CD with organic compounds, including polymers, was also reviewed by Szejtli [6, 12, 13], y - CD are able to incorporate metal ions as ligands to prepare magnetic nano - particles [7,14], Harada and Ka-machi [8,15] first found that poly (ethylene oxide) (PEO) thread a- CD rings to form polymer - cyclodextrin complex. Since their finding of inclusion complex formation of polymer chains with a- CD, a large number of studies on inclusion complexes of... 

The overwhelming interest on the developments of CD inclusion polymers arose since the discovery of a-CD inclusion complexes with PEO of different molecular weights [16] and the subsequent synthesis of the polyrotaxanes composed of multiple a-CD rings threaded and entrapped on a polymer chain (Fig. 2) [17,18], So far, a large number of reports have been published on the CD-based polypseudorotaxanes and polyrotaxanes [12,18 19] and their applications in biomaterials [50-58],... 

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