Visible light‐induced thiol‐ene reaction: A new strategy to prepare Α,ω‐dithiol and Α,ω‐divinyl telechelic polythiolether oligomers

Abstract

A new strategy is developed to prepare both a,xdithiol and a,x-divinyl linear telechelic polythiolether oligomers by visible light induced thiol-ene chemistry in the presence of a fac-Ir(ppy) 3 photoredox catalyst. Polythiolether oligomers of well-defined end groups and controlled molecular weights have been successfully synthesized at varying monomer molar ratios of 1,4-benzenedimethanethiol (BDMT) to diethylene glycol divinyl ether (DEGVE).

Oxidation‐Responsive Materials: Biological Rationale, State of the Art, Multiple Responsiveness, and Open Issues

“…Compatibility with Thiol Click Chemistries : “Click” reactions are typically quantitative processes occurring under mild conditions and with a reactivity often orthogonal to those of most other functional groups; these versatile processes are extensively used in polysulfide synthesis. For example, thiol‐ene reactions are used in the preparation of (protected) initiators for episulfide polymerization, as the propagation (and cross‐linking) steps (see also the recent review by Araujo), as end‐capping reactions, for post‐polymerization curing, or as side‐chain modifiers . Michael‐type addition has also been widely used as a propagation reaction (for poly(ester sulfide)s), for end‐capping/chain extension, and cross‐linking purposes …”

Thiol‐Ene Cationic and Radical Reactions: Cyclization, Step‐Growth, and Concurrent Polymerizations for Thioacetal and Thioether Units

“…Recently, Tew and Sarapas reported the synthesis of functional poly(thioether)s, by radical step‐growth polymerizations between a functional dithiol and divinyl ether, and their application as lithium polymer electrolytes . In addition, various thiols and vinyl ethers have been subjected to radical step‐growth polymerizations for other applications . In contrast to the radical polymerizations for poly(thioether)s, the groups of Ruckenstein and Hashimoto independently reported the synthesis of poly(acetal)s by cationic step‐growth polymerization between a diol and divinyl ether in the presence of acidic catalysts such as PTSA, and then applied the acetal linkages as degradable units .…”

“…[43,44] In addition, various thiols and vinyl ethers have been subjected to radical step-growth polymerizations for other applications. [45][46][47][48] In contrast to the radical polymerizations for poly(thioether)s,t he groups of Ruckenstein and Hashimoto independently reported the synthesis of poly(acetal)s by cationic step-growth polymerization between ad iol and divinyl ether in the presence of acidic catalysts such as PTSA, and then applied the acetal linkages as degradable units. [49][50][51][52][53] However,t here have been neither reports on cationic stepgrowth polymerization between ad ithiol and divinyl ether nor on concurrent radical and cationic step-growth polymerizations,e xcept for ac ombination of radical thiol-ene stepgrowth radical polymerization and chain-growth cationic photopolymerization of vinyl ether for preparing crosslinked materials.…”

Polythioethers with Controlled α,ω‐End Groups Prepared by Visible Light Induced Thiol–Ene Click Polymerization of Dithiol and Divinyl Ether with 4‐(N,N‐diphenylamino)benzaldehyde as Organocatalyst

“…The results showed that both the M n and end‐group of the product can be controlled by adjusting the reaction time and the molar ratio of the monomers. [ 35 ] However, transition metal polypyridine complexes are very expensive and toxic.…”

“…The reaction conditions between BDMT and DEGVE are mild and the reaction process is well‐controlled. [ 5,35 ]…”