The sequence� of monomer units along a polymer chain is the most essential structural factor in biopolymers to express unique functions. We have achieved �repetitive and periodic� sequences (e.g., ABABAB and ABAABA) in vinyl polymers by radical polymerizations with designed �template monomers�.1)  This work is to propose a new concept of sequence control: the �bipedal walking template� for discretionary or aperiodic sequences via repetitive 'single monomer addition' in radical polymerization. The walking templates were designed to carry a pair of cleavable bonds that meet the following criteria. 1) orthogonal  : independently cleavable by different stimulus without affecting each other; 2) cleaving  : quantitatively cleavable by �scissors� molecules via substitution (like SN2); and 3) renewing  : reproducing the same cleavable bonds. The combination of N-hydroxysuccinimide ester and pyridyl disulfide met the criteria and were thereby employed to attach a pair of initiator and monomer units onto a template framework to demonstrate the validity of this concept by a repetitive cyclopolymerization, as illustrated in the scheme.1) Hibi, Y.; Ouchi, M.; Sawamoto, M. Angew. Chem. Int. Ed. 2011  , 50(32), 7434-7437.

Sequence-controlling radical polymerization with template molecules

246th National Meeting (2013)

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