Cobalt‐Mediated Switchable Catalysis for the One‐Pot Synthesis of Cyclic Polymers

Zhao, Yajun; Zhu, Shenghuo; Liao, Can; Wang, Yong; Lam, Jacky W. Y.; Zhou, Xingping; Wang, Xianhong; Xie, Xiaolin; Tang, Ben Zhong

doi:10.1002/ange.202106285

Cited by 7 publications

(2 citation statements)

References 70 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, the double logarithmic plot of intrinsic viscosity versus MW reveals that at the same molecular weight, poly(CHO- alt -SA) heated for 24 h has a lower intrinsic viscosity compared to the polymer made at 1 h confirming a cyclic structure of the polymer (see Supporting Information, Figure S33). This is the rare example of cyclic polyesters made from ROCOP of epoxides and cyclic anhydrides that could be synthesized in major quantity. , A mechanism for the cyclization is proposed in Figure . There is a zwitterionic interaction between the alkoxide chain end and cationic pyridinium moiety keeping them in close proximity.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Ring-Opening Co- and Terpolymerization of Epoxides, Cyclic Anhydrides, and l-Lactide Using Constrained Aluminum Inden Complexes

et al. 2022

View full text Add to dashboard Cite

Seven constrained aluminum inden complexes having different substituents and diamine backbones were developed for the ring-opening copolymerization (ROCOP) of epoxides and bulky cyclic anhydrides giving alternating polyesters with T g ranging from 49 to 226 °C. Among several catalyst/cocatalyst screenings, the aluminum inden complex having a rigid phenylene backbone coupled with 4-dimethylaminopyridine showed the best performance giving linear polyesters. In the case of cyclohexene oxide (CHO) and succinic anhydride (SA), the linear poly(CHO-alt-SA) could be transformed to cyclic polymer when the polymerization was left under prolonged reaction time to induce intramolecular transesterification. The kinetic studies of the ROCOP revealed a zeroth-order dependence on cyclic anhydride and a first-order dependence on epoxide and the catalyst. The catalysts can be extended efficiently to the one-pot CHO/PA/l-lactide terpolymerization giving uncommon tapered copolymers of poly(CHO-alt-PA) and PLA via switchable polymerization.

show abstract

Section: Resultsmentioning

confidence: 99%

“…This is the rare example of cyclic polyesters made from ROCOP of epoxides and cyclic anhydrides that could be synthesized in major quantity. 24,73 A mechanism for the cyclization is proposed in Figure 8. There is a zwitterionic interaction between the alkoxide chain end and cationic pyridinium moiety keeping them in close proximity.…”

Section: ■ Introductionmentioning

confidence: 99%

Ring-Opening Co- and Terpolymerization of Epoxides, Cyclic Anhydrides, and l-Lactide Using Constrained Aluminum Inden Complexes

et al. 2022

View full text Add to dashboard Cite

show abstract

Switchable Polymerization Organocatalysis: From Monomer Mixtures to Block Copolymers

Tang

Wang

et al. 2022

Angewandte Chemie

Self Cite

View full text Add to dashboard Cite

One‐pot production of sequence‐controlled block copolymer from mixed monomers is a crucial but rarely reached goal. Using a switchable Lewis‐pair organocatalyst, we have accomplished sequence‐selective polymerization from a mixture of O‐carboxyanhydride (OCA) and epoxide. Polymerization of the OCA monomer occurs first and exclusively because of its exceedingly high polymerizability. When OCA is fully consumed, alternating copolymerization of epoxide and CO2 liberated in OCA polymerization is triggered from the termini of the first block. The two polymerizations thus occur in tandem, both in chemoselective fashion, so that a sequence‐controlled block polymer with up to 99 % CO2 conversion is furnished in this one‐pot protocol. Calculations and experimental results demonstrate a chemoselective and cooperative mechanism, where the high polymerizability of the OCA monomers guarantees exquisite sequence selectivity and the cooperative decarboxylation partly arose from the stabilization effect by triethylborane, which facilitates the smooth transformation of the chain end from carbonate to alkoxide.

show abstract

Controlled Synthesis of Cyclic‐Helical Polymers with Circularly Polarized Luminescence

Gao

et al. 2022

Angewandte Chemie

View full text Add to dashboard Cite

Cyclic polymers attract attention because of their endless structure and unique properties, which differ from the linear analogs. However, the synthesis of cyclic polymers is difficult and prohibits their functions and applications. In this study, we reported chiral cyclic Pd II -catalysts that initiate a living ring-expansion polymerization of isocyanides, yielding a single-handed cyclic-helical poly(phenyl isocyanide), with predictable molecular weight (M n ) and low dispersity (M w /M n ), in good yield. Using this method, cyclic bottlebrush polymers were prepared via the grafting-onto strategy. The cyclic topology was confirmed using various spectroscopic data and atomic force microscope observation. Moreover, the cyclic polymer brushes, comprising of a one-handed helical backbone, showed interesting photoluminescence and circularly-polarized luminescence.

show abstract

Cobalt‐Mediated Switchable Catalysis for the One‐Pot Synthesis of Cyclic Polymers

Cited by 7 publications

References 70 publications

Ring-Opening Co- and Terpolymerization of Epoxides, Cyclic Anhydrides, and l-Lactide Using Constrained Aluminum Inden Complexes

Ring-Opening Co- and Terpolymerization of Epoxides, Cyclic Anhydrides, and l-Lactide Using Constrained Aluminum Inden Complexes

Switchable Polymerization Organocatalysis: From Monomer Mixtures to Block Copolymers

Controlled Synthesis of Cyclic‐Helical Polymers with Circularly Polarized Luminescence

Contact Info

Product

Resources

About