A Strategy toward Cyclic Topologies Based on the Dynamic Behavior of a Bis(hindered amino)disulfide Linker

Abstract

A simple and efficient method to generate macrocyclic structures has been developed based on the dynamic behavior of the linker bis(2,2,6,6‐tetramethylpiperidin‐1‐yl)disulfide (BiTEMPS). The prime linear structure was transformed into a (macro)cycle using the following sequence: 1) thiol–ene reaction with a BiTEMPS derivative to afford the linear precursor, then 2) an entropy‐driven transformation induced by diluting and heating. The radicals generated from BiTEMPS upon heating are highly tolerant toward a variety of chemical species, including oxygen and olefins, but they exhibit high reactivity in exchange reactions, which can be applied to the topology transformation of various skeletons. The advantages of the present method, namely, its procedural simplicity and substrate versatility, are demonstrated by the gram‐scale synthesis of cyclic compounds with low and relatively high molecular weight.

Effect of bulky 2,6-bis(spirocyclohexyl)-substituted piperidine rings in bis(hindered amino)trisulfide on thermal healability of polymethacrylate networks

“…By virtue of the unique dynamic behavior, BITEMPS-S2 were utilized to impart the specific features such as self-healing and reprocessable cross-linked polymers, the fusion of different cross-linked polymers, the topological rearrangement from linear to cyclic polymers, and self-strengthening of cross-linked elastomers. [10][11][12][13][14][15][16] Afterward, we reported that the trisulfide analogue of BITEMPS-S2, bis(2,2,6,6-tetramethylpiperidin-1-yl)trisulfide (BITEMPS-S3), also behave as an DCB to produce air-stable thiyl and dithiyl radicals upon heating at mild temperature (as shown in Scheme 1b). 17 Additionally, poly(n-hexylmethacrylate) network containing BITEMPS-S3 units at cross-linking points afforded nearly quantitative damage healability only by simple hot pressing at 110 °C for 24 h, which were almost comparable to one containing BITEMPS-S2 units (100 °C for 24 h).…”

Based on transalkylation reaction the rearrangeable conventional sulfur network facile design for vulcanized diolefin elastomers

“…[11][12][13] Through the electron cloud density regulation of disulfide bonds and addition of catalysts, disulfide bonds can be weakened, which is further beneficial for the reversibility of disulfide bond crosslinks. [14][15][16][17][18][19] Besides disulfide bonds, the Diels-Alder reactions, [20][21][22] coordination bonds, [23][24][25] ionic bonds, 26,27 transesterification, [28][29][30][31] and imine bonds 32,33 can be used as dynamic bond network in the elastomers. The characteristic of previous investigations mainly focuses on replacing the conventional sulfur network with a novel reversible crosslinking network.…”

“…Based on such reversibility of disulfide bonds, disulfide bonds are used as crosslinks to realize crosslinking network rearrangements in elastomers 11–13 . Through the electron cloud density regulation of disulfide bonds and addition of catalysts, disulfide bonds can be weakened, which is further beneficial for the reversibility of disulfide bond crosslinks 14–19 . Besides disulfide bonds, the Diels–Alder reactions, 20–22 coordination bonds, 23–25 ionic bonds, 26,27 transesterification, 28–31 and imine bonds 32,33 can be used as dynamic bond network in the elastomers.…”

Acyclic Diene Metathesis (ADMET) Polymerization of 2,2,6,6‐Tetramethylpiperidine‐1‐sulfanyl (TEMPS) Dimers

“…By virtue of their unique dissociation features, BiTEMPS were initially utilized as cross-linking point within polymer networks to impart a thermally induced healing property. [15] Despite the elegant achievements based on the dynamic behavior of BiTEMPS derivatives, [16] such as the fusion of different crosslinked polymers, [17] the topological rearrangement from linear to cyclic polymers, [18,19] and synthesis of end-functionalized Macromol. Rapid Commun.…”

“…By virtue of their unique dissociation features, BiTEMPS were initially utilized as cross‐linking point within polymer networks to impart a thermally induced healing property. [ 15 ] Despite the elegant achievements based on the dynamic behavior of BiTEMPS derivatives, [ 16 ] such as the fusion of different cross‐linked polymers, [ 17 ] the topological rearrangement from linear to cyclic polymers, [ 18,19 ] and synthesis of end‐functionalized polymers, [ 20 ] to the best of our knowledge, the protocols utilized for the preparation of BiTEMPS containing polymers has been limited to conventional free‐radical or step‐growth polymerization approaches. Critically, due to the thermal lability of the BiTEMPS unit at temperatures above 80 °C, [ 14 ] previously reported polymerizations were essentially performed at ambient temperatures (Scheme 1B,C).…”