Backbone-Photodegradable Polymers by Incorporating Acylsilane Monomers via Ring-Opening Metathesis Polymerization

Abstract

Materials capable of degradation upon exposure to light hold promise in a diverse range of applications including biomedical devices and smart coatings. Despite the rapid access to macromolecules with diverse compositions and architectures enabled by ring-opening metathesis polymerization (ROMP), a general strategy to introduce facile photodegradability into these polymers is lacking. Here, we report copolymers synthesized via ROMP that can be degraded by cleaving the backbone in both solution and solid states under irradiation with a 52 W, 390 nm Kessil LED to generate heterotelechelic low-molecular-weight fragments. To the best of our knowledge, this work represents the first instance of the incorporation of acylsilanes into a polymer backbone. Mechanistic investigation of the degradation process supports the intermediacy of an α-siloxy carbene, formed via a 1,2-photo Brook rearrangement, which undergoes insertion into water followed by cleavage of the resulting hemiacetal.

Sigmatropic Rearrangements of Polymer Backbones: Vinyl Polymers from Polyesters in One Step

“…45 Lastly, formally sigmatropic 1,2-Brook rearrangements were recently utilized to do skeletal editing of polymer chains. 46,47 Though scarce, these precedents provide a sound framework for further advances. To initiate a systematic investigation of PBM via sigmatropic rearrangements, we set out to demonstrate the power of the Ireland−Claisen rearrangement 48,49 (ICR) to transform polyesters into vinyl polymers (Figure 1B).…”

“…More than a century since the first report of sigmatropic rearrangements in 1912, only 11 studies have explored them in the context of polymers. − Five of these studies are theoretical: Roald Hoffmann and co-workers investigated intriguing hypothetical classes of polymers they called “sigmatropic shiftamers,” because they predicted sigmatropic shiftseither Cope rearrangements or [1, n ]-hydride shiftswould render the polymer fluxional along its entire backbone. − The other six studies were experimental and utilized (orthoester-)­Claisen rearrangements for peripheral modification of polyaramids and polyimides − or the surface of graphene oxide, or diaza-Cope rearrangement to mediate step-growth polymerization of diamines and dialdehydes . Lastly, formally sigmatropic 1,2-Brook rearrangements were recently utilized to do skeletal editing of polymer chains. , Though scarce, these precedents provide a sound framework for further advances. To initiate a systematic investigation of PBM via sigmatropic rearrangements, we set out to demonstrate the power of the Ireland–Claisen rearrangement , (ICR) to transform polyesters into vinyl polymers (Figure B).…”

Ruthenium-catalyzed diazoacetate/cyclooctene metathesis copolymerization

“…[6][7][8][9][10][11] For example, the copolymerization of cyclooctene (COE) or norbornene with different polar comonomers can generate different functionalized copolymers. [12][13][14][15][16][17][18][19][20][21][22] Specifically, the ROMP of COE with chaintransfer agents produces telechelic polymers (Scheme 1a); [13][14][15][16] the ROMP of COE with cyclic monomers generates different types of copolymers (Scheme 1b); [17][18][19][20] and the ROMP of COE with unsaturated diene monomers affords alternating copolymers (Scheme 1c). 21,22 The above-mentioned polar functional comonomers are usually olefin type reagents bearing CvC bonds.…”

Controllable synthesis and structural design of novel all-organic polymers toward high energy storage dielectrics

“…ROMP is a relatively new research field in the preparation of polymer materials, which has all the characteristics of olefin metathesis reactions. Due to its high reactivity, it has become a widely used synthetic method for the preparation of polymer materials with controllable structures ( Lu L. et al, 2020 ; Varlas et al, 2020 ; Huang et al, 2021 ; Blosch et al, 2022a ; Feist et al, 2022 ; Quach et al, 2022 ; Yu et al, 2022 ). In the past few decades, most of the research on ROMP has focused on its reaction mechanism, catalysts, and the exploration of new monomers.…”