Synthesis of vinyl iodide chain-end polymers via organocatalyzed chain-end transformation.

In the presence of alkynes (CHC–R2), iodide chain-end polymers (Polymer–I) were successfully transformed to vinyl iodide chain-end polymers (polymer–CHCR2–I) in a single step via organocatalysis. This reaction is completely metal-free and easy to carry out without using special reagents or special conditions. The polymers encompassing polyacrylates and polymethacrylate, and additional functionalities (e.g., OH and CF3) were also incorporated into the R2 moiety. The obtained Polymer–CHCR2–I further served as a useful precursor for copper-catalyzed cross-coupling reactions with various thiols (R3–SH) to yield vinyl sulfide chain-end polymers (polymer–CHCR2–SR3) with various R3 moieties. Interestingly, under selected conditions, this organocatalysis also offered block-like copolymers containing a conjugated oligo-alkyne segment and a non-conjugated polyacrylate segment. Exploiting the unique structure, the block-like copolymer was used as an efficient dispersant of carbon nanotubes.