Well‐Defined Poly(Ester Amide)‐Based Homo‐ and Block Copolymers by One‐Pot Organocatalytic Anionic Ring‐Opening Copolymerization of <i>N</i>‐Sulfonyl Aziridines and Cyclic Anhydrides

Xu, Jiaxi; Hadjichristidis, N.

doi:10.1002/ange.202015339

Cited by 12 publications

(4 citation statements)

References 30 publications

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“…Romain and Williams first reported a “switchable” dizinc catalyst that links the ring-opening copolymerization (ROCOP) or CO 2 /cyclohexene oxide (CHO) with the ring-opening polymerization (ROP) of ε-caprolactone to form block polymers . Subsequently, they demonstrated this switchable catalysis concept using anhydride/epoxide/lactone mixtures. , The same catalysis rules have been applied to numerous catalyst systems to prepare various block copolymers. − Recently, switchable polymerization was extended to the ROCOPs of N -sulfonyl aziridines/cyclic anhydrides, epoxides/carbonyl sulfide, and epoxide/thioanhydride, thus increasing the constitutional block diversity. − However, switchable polymerization requires huge reactivity differences among monomers. As such monomer reactivity ratios are relatively easy to achieve in three-component ( n = 3) systems; this method has mainly been applied to the production of di- or triblock copolymers (AB or ABA-type).…”

Section: Introductionmentioning

confidence: 99%

Sequential Polymerization from Complex Monomer Mixtures: Access to Multiblock Copolymers with Adjustable Sequence, Topology, and Gradient Strength

Xia

Gao

et al. 2022

Macromolecules

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Switchable polymerization shows considerable potential for simulating the molecular precision of natural biopolymers, such as nucleic acids or proteins, to synthesize highly sequence-controlled macromolecules but is mainly limited to three-and four-component systems. To expand the scope to systems with up to five components, we established a reactivity gradient among 12 monomers, including cyclic anhydrides, cyclic esters, and epoxides. Highly selective competitive anhydride/epoxide, selfswitchable cyclic anhydride/epoxide/cyclic ester, and competitive cyclic ester/trimethylene carbonate copolymerizations were achieved using a simple alkyl metal carboxylate catalyst. Anhydrides gave access to gradient copolymers with reactivity ratios of 2 < r 1 < 5, 0.7 > r 2 > 0.3 giving medium-gradient copolymers and r 1 > 400, r 2 < 0.03 giving block copolymers. Further, the anhydride reactivity was predicted using 13 C NMR chemical shifts. This comonomer library will allow more complex copolymer structures with adjustable sequence, topology, and gradient strength to be predicted and prepared.

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Section: Introductionmentioning

confidence: 99%

Sequential Polymerization from Complex Monomer Mixtures: Access to Multiblock Copolymers with Adjustable Sequence, Topology, and Gradient Strength

Xia

Gao

et al. 2022

Macromolecules

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“…For the ROAC of TAz and PA, in the report by Hadjichristidis et al, a sole t-BuP 1 catalyst was used with a sulfonamide initiator at room temperature. 36 In our study, when the sulfonamide initiator was replaced with the alcohol initiator BDM, the TAz/ PA ROAC maintained a high polymerization rate with 80.5% of TAz consumed in 23 h at room temperature (Table S1, run 6). The addition of 0.25 equiv of TEB, however, decreases the polymerization rate, resulting in the consumption of 85.7% of TAz in 51 h (Table S1, run 7).…”

Section: ■ Results and Discussionmentioning

confidence: 56%

“…By analyzing the relative peak intensities of “1” and “2” in the terpolymers, a clear shift in the initiation of polymerization from PA-TAz to PA-CHO upon the addition of TEB is evident. Furthermore, the intensities of signals “3” and “4” corresponding to the TAz unit in the chain end, progressively increased from runs 3 to 8 in Table , confirming a transition of the PA/CHO ω chain end to the PA/TAz ω chain end . Additionally, signals marked with brown-filled circles are presumably associated with the tapered region or the linking units between two blocks, as they are neither observed on poly(CHO- alt -PA) nor on poly(TAz- alt -PA).…”

Section: Resultsmentioning

confidence: 91%

“…Furthermore, the intensities of signals "3" and "4" corresponding to the TAz unit in the chain end, progressively increased from runs 3 to 8 in Table 1, confirming a transition of the PA/CHO ω chain end to the PA/ TAz ω chain end. 36 Additionally, signals marked with brownfilled circles are presumably associated with the tapered region or the linking units between two blocks, as they are neither observed on poly(CHO-alt-PA) nor on poly(TAz-alt-PA). Their relatively high peak intensity in the samples from runs 3, 5, and 6 in Table 1 corroborates their gradient and random-like structures determined via the monitoring of monomer conversion.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Toward Fully Controllable Monomers Sequence: Binary Organocatalyzed Polymerization from Epoxide/Aziridine/Cyclic Anhydride Monomer Mixture

Gao,

Xia,

Watanabe

et al. 2024

J. Am. Chem. Soc.

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The sequence of monomers within a polymer chain plays a pivotal role in determining the physicochemical properties of the polymer. In the copolymerization of two or more monomers, the arrangement of monomers within the resulting polymer is primarily dictated by the intrinsic reactivity of the monomers. Precisely controlling the monomer sequence in copolymerization, particularly through the manipulation of catalysts, is a subject of intense interest and poses significant challenges. In this study, we report the catalyst-controlled copolymerization of epoxides, N-tosyl aziridine (TAz), and cyclic anhydrides. To achieve this, a binary catalyst system comprising a Lewis acid, triethylborane, and Brønsted base, t-BuP 1 , was utilized. This system was utilized to regulate the selectivity between two catalytic reactions: ring-opening alternating copolymerization (ROAC) of epoxides/cyclic anhydrides and ROAC of TAz/cyclic anhydrides. Changing the catalyst ratio made it possible to continuously modulate the resulting poly(ester−amide ester) from ABAtype real block copolymers to gradient, random-like, reversed gradient, and reversed BAB-type block-like copolymers. A range of epoxides and anhydrides was investigated, demonstrating the versatility of this polymerization system. Additionally, density functional theory calculations were conducted to enhance our mechanistic understanding of the process. This synthetic method not only provides a versatile means for producing copolymers with comparable chemical compositions but also facilitates the exploration of the intricate relationship between monomer sequences and the resultant polymer properties, offering valuable insights for advancements in polymer science.

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Heterocycle/Heteroallene Ring‐Opening Copolymerization: Selective Catalysis Delivering Alternating Copolymers

Williams

Plajer

2021

Angewandte Chemie

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Heteroatom‐containing polymers have strong potential as sustainable replacements for petrochemicals, show controllable monomer–polymer equilibria and properties spanning plastics, elastomers, fibres, resins, foams, coatings, adhesives, and self‐assembled nanostructures. Their current and future applications span packaging, house‐hold goods, clothing, automotive components, electronics, optical materials, sensors, and medical products. An interesting route to these polymers is the catalysed ring‐opening copolymerisation (ROCOP) of heterocycles and heteroallenes. It is a living polymerization, occurs with high atom economy, and creates precise, new polymer structures inaccessible by traditional methods. In the last decade there has been a renaissance in research and increasing examples of commercial products made using ROCOP. It is better known in the production of polycarbonates and polyesters, but is also a powerful route to make N‐, S‐, and other heteroatom‐containing polymers, including polyamides, polycarbamates, and polythioesters. This Review presents an overview of the different catalysts, monomer combinations, and polymer classes that can be accessed by heterocycle/heteroallene ROCOP.

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Well‐Defined Poly(Ester Amide)‐Based Homo‐ and Block Copolymers by One‐Pot Organocatalytic Anionic Ring‐Opening Copolymerization of N‐Sulfonyl Aziridines and Cyclic Anhydrides

Cited by 12 publications

References 30 publications

Sequential Polymerization from Complex Monomer Mixtures: Access to Multiblock Copolymers with Adjustable Sequence, Topology, and Gradient Strength

Sequential Polymerization from Complex Monomer Mixtures: Access to Multiblock Copolymers with Adjustable Sequence, Topology, and Gradient Strength

Toward Fully Controllable Monomers Sequence: Binary Organocatalyzed Polymerization from Epoxide/Aziridine/Cyclic Anhydride Monomer Mixture

Heterocycle/Heteroallene Ring‐Opening Copolymerization: Selective Catalysis Delivering Alternating Copolymers

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