scholarly journals Water-Assisted and Protein-Initiated Ring-Opening Polymerization of Proline N-Carboxyanhydride

2021 ◽  
Author(s):  
Yali Hu ◽  
Zi-You Tian ◽  
wei xiong ◽  
HUA LU
Keyword(s):  
Ring Opening ◽  
Density Functional ◽  
Biological Activities ◽  
Functional Materials ◽  
Monomer Conversion ◽  
Ring Opening Polymerization ◽  
Type I ◽  
Stringent Requirement ◽  
Native Proteins ◽  
Grafting From

<p>The production of poly-<sub>L</sub>-proline (PLP) via the ring-opening polymerization (ROP) of <sub>L</sub>-proline <i>N</i>-carboxyanhydride (ProNCA) is challenging due to a combination of factors, including the stringent requirement of moisture-free conditions, slow monomer conversion, poor control of the molar mass, and premature precipitation of the product in the form of polyproline type I helix. Here, we report water-assisted ROP of ProNCA, which affords well-defined PLP in polyproline II helix in 2-5 minutes. Density functional theory reveals an as-yet-unreported role of water in facilitating proton shift that significantly lowered the energy barrier of the chain propagation. Protein-mediated ROP of ProNCA conveniently affords various protein-PLP conjugates via a grafting-from approach. PLP conjugation not only preserves the biological activities of the native proteins, but also enhances the stability of proteins against extreme conditions. This work provides a simple means and new mechanistic insight to solve a longstanding problem in PLP synthesis and will offer valuable guidance for the development of water-resistant ROP of other NCAs. The facile access of PLP can greatly boost the application potentials of PLP-based functional materials.<b></b></p>

scholarly journals Water-Assisted and Protein-Initiated Ring-Opening Polymerization of Proline N-Carboxyanhydride

2021 ◽  
Author(s):  
Yali Hu ◽  
Zi-You Tian ◽  
wei xiong ◽  
HUA LU
Keyword(s):  
Ring Opening ◽  
Density Functional ◽  
Biological Activities ◽  
Functional Materials ◽  
Monomer Conversion ◽  
Ring Opening Polymerization ◽  
Type I ◽  
Stringent Requirement ◽  
Native Proteins ◽  
Grafting From

<p>The production of poly-<sub>L</sub>-proline (PLP) via the ring-opening polymerization (ROP) of <sub>L</sub>-proline <i>N</i>-carboxyanhydride (ProNCA) is challenging due to a combination of factors, including the stringent requirement of moisture-free conditions, slow monomer conversion, poor control of the molar mass, and premature precipitation of the product in the form of polyproline type I helix. Here, we report water-assisted ROP of ProNCA, which affords well-defined PLP in polyproline II helix in 2-5 minutes. Density functional theory reveals an as-yet-unreported role of water in facilitating proton shift that significantly lowered the energy barrier of the chain propagation. Protein-mediated ROP of ProNCA conveniently affords various protein-PLP conjugates via a grafting-from approach. PLP conjugation not only preserves the biological activities of the native proteins, but also enhances the stability of proteins against extreme conditions. This work provides a simple means and new mechanistic insight to solve a longstanding problem in PLP synthesis and will offer valuable guidance for the development of water-resistant ROP of other NCAs. The facile access of PLP can greatly boost the application potentials of PLP-based functional materials.<b></b></p>

A Recommender System for Inverse Design of Polycarbonates and Polyesters

2020 ◽  
Author(s):  
Nathaniel Park ◽  
Dmitry Yu. Zubarev ◽  
James L. Hedrick ◽  
Vivien Kiyek ◽  
Christiaan Corbet ◽  
...  
Keyword(s):  
Ring Opening ◽  
High Performance ◽  
Recommendation System ◽  
Polymeric Materials ◽  
Monomer Conversion ◽  
Design Strategy ◽  
Ring Opening Polymerization ◽  
Inverse Design ◽  
False Negatives ◽  
Accelerate Development

The convergence of artificial intelligence and machine learning with material science holds significant promise to rapidly accelerate development timelines of new high-performance polymeric materials. Within this context, we report an inverse design strategy for polycarbonate and polyester discovery based on a recommendation system that proposes polymerization experiments that are likely to produce materials with targeted properties. Following recommendations of the system driven by the historical ring-opening polymerization results, we carried out experiments targeting specific ranges of monomer conversion and dispersity of the polymers obtained from cyclic lactones and carbonates. The results of the experiments were in close agreement with the recommendation targets with few false negatives or positives obtained for each class.<br>

A Density Functional Theory Study on the Ring-Opening Polymerization of D-Lactide Catalyzed by a Bifunctional-Thiourea Catalyst

2009 ◽  
Vol 62 (2) ◽  
pp. 157 ◽  
Author(s):  
Rong-Xiu Zhu ◽  
Ruo-Xi Wang ◽  
Dong-Ju Zhang ◽  
Cheng-Bu Liu
Keyword(s):  
Density Functional Theory ◽  
Ring Opening ◽  
Density Functional ◽  
Population Analysis ◽  
Density Functional Theory Calculations ◽  
Ring Opening Polymerization ◽  
Acyl Transfer ◽  
Frontier Molecular Orbital ◽  
Functional Theory ◽  
Elimination Pathway

The thiourea-catalyzed methanolysis of d-lactide, a model system for the initiation and propagation of the organocatalyzed ring-opening polymerization (ROP) of lactide, has been studied by performing density functional theory calculations. Both the catalyzed and uncatalyzed reactions are explored along two possible pathways: one involves the stepwise addition–elimination pathway and the other is related to the concerted pathway. It is found that the reaction without the presence of the catalyst is difficult because the barrier involved is as high as 176 kJ mol–1. With the aid of a thiourea catalyst, the barrier is reduced to 88 kJ mol–1 with a preference for the stepwise addition–elimination mechanism over the concerted one. The role of the catalyst has been rationalized by analyzing the frontier molecular orbital interactions between the catalyst and substrates and by performing natural population analysis. Finally, another mechanism involving acyl transfer is discussed for the thiourea-catalyzed ROP.

scholarly journals A chiral thiourea and a phosphazene for fast and stereoselective organocatalytic ring-opening-polymerization of racemic lactide

2021 ◽  
Author(s):  
Samir Mohamed ZAKY ◽  
Anne-Laure Wirotius ◽  
Olivier Coulembier ◽  
Gilles Guichard ◽  
Daniel Taton
Keyword(s):  
Ring Opening ◽  
Functional Materials ◽  
Ring Opening Polymerization

Control of stereoregularity is inherent to precision polymerization chemistry for the development of functional materials. A prototypal example of this strategy is the ring-opening polymerization (ROP) of racemic lactide (rac-LA),...

scholarly journals DFT Modeling of Organocatalytic Ring-Opening Polymerization of Cyclic Esters: A Crucial Role of Proton Exchange and Hydrogen Bonding

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2078 ◽  
Author(s):  
Ilya Nifant’ev ◽  
Pavel Ivchenko
Keyword(s):  
Ring Opening ◽  
Density Functional ◽  
Comparative Modeling ◽  
Ring Opening Polymerization ◽  
Proton Exchange ◽  
Dft Methods ◽  
Experimental Proof ◽  
Cyclic Esters ◽  
Dft Modeling

Organocatalysis is highly efficient in the ring-opening polymerization (ROP) of cyclic esters. A variety of initiators broaden the areas of organocatalysis in polymerization of different monomers, such as lactones, cyclic carbonates, lactides or gycolides, ethylene phosphates and phosphonates, and others. The mechanisms of organocatalytic ROP are at least as diverse as the mechanisms of coordination ROP; the study of these mechanisms is critical in ensuring the polymer compositions and architectures. The use of density functional theory (DFT) methods for comparative modeling and visualization of organocatalytic ROP pathways, in line with experimental proof of the structures of the reaction intermediates, make it possible to establish these mechanisms. In the present review, which continues and complements our recent manuscript that focused on DFT modeling of coordination ROP, we summarized the results of DFT modeling of organocatalytic ROP of cyclic esters and some related organocatalytic processes, such as polyester transesterification.

scholarly journals Mechanistic Insight into the Ring-Opening Polymerization of ɛ-Caprolactone and L-Lactide Using Ketiminate-Ligated Aluminum Catalysts

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1530 ◽  
Author(s):  
Lin ◽  
Jheng
Keyword(s):  
Thermal Effects ◽  
Ring Opening ◽  
Density Functional ◽  
Bond Cleavage ◽  
Ring Opening Polymerization ◽  
Catalyst Design ◽  
Reaction Conditions ◽  
Functional Theory ◽  
Cleavage Step ◽  
Insight Into

The reactivity and the reaction conditions of the ring-opening polymerization of ɛ-caprolactone (ɛ-CL) and L-lactide (LA) initiated by aluminum ketiminate complexes have been shown differently. Herein, we account for the observation by studying the mechanisms on the basis of density functional theory (DFT) calculations. The calculations show that the ring-opening polymerization of ɛ-CL and LA are rate-determined by the benzoxide insertion and the C–O bond cleavage step, respectively. Theoretical computations suggest that the reaction temperature of L–LA polymerization should be higher than that of ɛ-CL one, in agreement with the experimental data. To provide a reasonable interpretation of the experimental results and to give an insight into the catalyst design, the influence of the electronic, steric, and thermal effects on the polymerization behaviors will be also discussed in this study.

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