Facile synthesis of dual-responsive thioether-bridging graft copolymers by combination of controlled polymerization and thio-bromo click reaction

Facile synthesis of monocyclic, dumbbell-shaped and jellyfish-like copolymers using a telechelic multisite hexablock copolymer

“…In this study, c-PSM comprising thiolactone, hydroxyl and bromine groups was subjected to tandem amine-thio-bromo click reactions to form the dumbbell-shaped copolymer F1 (Scheme 1), followed by ROP to generate F2. F1 was initially synthesized by an intracyclic interblock thio-bromo click reaction [64][65][66][67] between the P(St-co-MTL) and P(St-co-BEMI) blocks of c-PSM (run 3 of Table 1). At a low concentration (c p = 1.0 mg mL −1 ), the MTL unit of c-PSM was subjected to aminolysis using a large excess of n-propylamine, and the resultant thiol moiety was in situ reacted with the bromine group to form a thioether linker.…”

“…The reactive groups can act as initiating and coupling moieties, in which the thiolactone unit is the precursor of the thiol group. A thio-bromo click reaction has been efficiently used for polymerization 64,65 and post-polymerization modification, 66,67 and it may hold great promise in the facile construction of single-ring folding polymers via intracyclic cross-linking. To this aim, a couplable chain transfer agent 3-(2-formyl-3-methylphenoxy)propyl 4-(benzodithioyl)-4-cyanopentanoate (FBCP) was adopted for the one-pot sequential reversible addition–fragmentation chain transfer (RAFT) copolymerization of excess styrene with 2-maleimidyl-4-thiobutyrolactone (MTL), N -(2-hydroxyethyl)maleimide (HEMI), and N -(2-(2-bromoisobutyroxy))ethyl maleimide (BEMI) to generate a linear (l) telechelic multisite hexablock copolymer P(St- co -MTL)- b -PSt- b -P(St- co -HEMI)- b -PSt′- b -P(St- co -BEMI)- b -PSt′′ (denoted as l-PSM, Scheme 1).…”

Playing construction with the monomer toy box for the synthesis of multi‐stimuli responsive copolymers by reversible deactivation radical polymerization protocols

“…Here, HEMA acts as a bifuncional unit for ROP (through the OH residue) and RAFT (with the conjugated double bond) and hyperbranched polymers that are responsive to temperature and reduction were thus obtained without the need for a specially designed RAFT agent. Tang et al 99 designed a polyfunctional initiator to obtain a PNIPAAm with a ω‐end dithiobenzoate, a α‐end alkyl bromide and a hydroxyl handle for subsequent ROP (Scheme 5). The ω‐thiol group revealed by aminolysis undergoes thiol‐bromo click with the α‐end, yielding a multisegmented PNIPAAm ready for ROP of CL at each segment.…”

“…PNIPAAm‐ g ‐PCL by successive RAFT process, thio‐bromo click reaction and ROP. Reproduced with permission 99 . Copyright Elsevier 2018.…”

Preparation and Characterization of Thermal and pH Dual Sensitive Hydrogel Based on 1,3‐Dipole Cycloaddition Reaction

“…They drew the criteria of a click reaction to be “modular and wide in scope, highly efficient, generate inoffensive or no byproducts, be stereospecific, use readily available starting materials, use benign or no solvent, and require simple purification techniques” [3]. Till date, several click reactions have been explored, such as Diels–Alder reaction [4, 5], tetrazine–norbornene chemistry [6], thiol–ene click reaction [7, 8], thio–bromo click reaction [9], thiol–yne click reaction [10], oxime “click” reaction [11], and thiol–epoxy click reaction [12]. Among these, copper‐catalyzed azide–alkyne cycloaddition (CuAAC) is one of the most powerful, widely employed techniques in organic synthesis, biochemistry, materials science, and surfaces and interfaces [13‐16].…”