Vinyl Iodide Containing Polymers Directly Prepared via an Iodo-yne Polymerization

Facile photochemical synthesis of main-chain-type semifluorinated alternating copolymers catalyzed by conventional amines or halide salts

In this work, we report a much simpler and low-cost method to prepare main-chain-type semifluorinated alternating copolymers by the formation of a halogen bond (XB) complex between α,ω-diiodoperfluoroalkanes and amines/halide salts. It is interesting that the terminal iodine functional group of the polymer chains is easily lost in the amine-promoted system, while the loss can be significantly reduced by adding a small amount of water. Importantly, the system promoted by halide salts can ensure complete retention of the iodine functional group. Overall, the establishment of this method provides a new strategy for designing smart fluoropolymer materials in a green and environmentally friendly facile manner under irradiation with visible light at room temperature.

Simple Synthesis of Fluorinated Ene-Ynes via In Situ Generation of Allenes

Fluorination of small molecules is a key route toward modulating reactivity and bioactivity. The 1,3 ene-yne functionality is an important synthon towards complex products, as well as a common functionality in biologically active molecules. Here, we present a new synthetic route towards fluorinated ene-ynes from simple starting materials. We employ gas chromatography-mass spectrometry analysis to probe the sequential eliminations necessary for this transformation and observe an allene intermediate. The ene-yne products are sufficiently fluorous to enable purification via fluorous extraction. This methodology will allow facile access to functional, fluorous ene-ynes.

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

In the presence of alkynes (CH[triple bond, length as m-dash]C-R2), iodide chain-end polymers (Polymer-I) were successfully transformed to vinyl iodide chain-end polymers (polymer-CH[double bond, length as m-dash]CR2-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-CH[double bond, length as m-dash]CR2-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-CH[double bond, length as m-dash]CR2-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.

Recent advances in the preparation of semifluorinated polymers

Synthesis of semifluorinated polymers containing fluorous groups on the backbone or as side chains is an increasingly popular field of research.