Polymers Formed by Dynamic Combinatorial Chemistry

Jean-Luc Wietor, Nicole E. Botterhuis, and Rint P. Sijbesma 

The second key element of DCC-reversibility-is a feature that is intrinsic to many polymers, specifically those that are formed by step polymerizations. Although the conditions under which bond formation takes place for the most common functional groups (esters, amides) are quite harsh, a large variety of bonding forming reactions that are reversible under mild conditions have been studied recently and have become known under the name of dynamic covalent chemistry. Reversibility is an even more prominent feature of supramolecular polymers - polymers in which the monomeric units are held together by noncova-lent bonds. 

Finally, the third key element of DCC-molecular recognition via multiple interactions-is a fundamental feature of polymers. Due to their size and architectural fiexibility, polymers are able to combine a large number of molecular recognition sites in virtually any spatial arrangement-the abundance of nucleic acids and 

Dynamic Combinatorial Chemistry. Edited by Joost N. H. Reek and Sijbren Otto 2010 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim ISBN 978-3-527-32122-3 

Exchangeabie Covaient Bonds-A Familiar Feature in Polymer Chemistry 

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Polymers Formed by Dynamic Combinatorial Chemistry Table 6.1 Corttinued. 

T 0 conclude this part on dynamic combinatorial chemistry, we will mention the use of a polymer bound N-methyl ammonium ion as a template. The library is generated from the pseudopeptide building block mPro, which gives a dynamic library of hydrazones (Fig. 23). Depending on the conditions, the following will be formed at equilibrium in the absence of a template, 85% of the cyclic dimer and 7% of the cyclic trimer in the presence of the template BTA, 47% of the dimer and 50% of the trimer and in the presence of the immobilized template. 40% of pure trimer can be isolated by washing the resin. 

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