Abstract
A highly soluble thymineโbased compound (1โoctyl thymine), having an array of hydrogen bonding sites with an ADA sequence (A and D: proton acceptor and donor sites, respectively), was used to mediate the stereospecific radical polymerization of an acrylamide monomer [Nโ(6โacetamidopyridinโ2โyl)acrylamide] possessing the complementary DAD sequence. The thymine derivative interacted with the monomer via the selective 1:1 and strong triple hydrogenโbonding interaction (Kโ=โ1.1โรโ10^3^ in CHCl~3~ at 20โยฐC) and mediated the syndiospecific radical polymerization of the monomer to give syndiotactic rich polymers up to rโ=โ84% in CH~2~Cl~2~ at โ78โยฐC. A combination with the RAFT polymerization enabled simultaneous control of the molecular weight ($\overline {M} _{{\rm w}} /\overline {M} _{{\rm n}} $โโโ1.5) and tacticity (rโ=โ73% and 76% at 60 and 20โยฐC, respectively) of the resulting polymers. Furthermore, the stereoblock polymerization was achieved upon the addition of the thymineโbased mediator during the RAFT polymerization to give the atacticโsyndiotactic stereoblock polymers with controlled molecular weights. magnified image