scholarly journals “Exhaustive” Baeyer-Villiger Oxidation of Poly(Methyl Vinyl Ketone) and Its Copolymers

2021 ◽  
Author(s):  
Pengfei Ma ◽  
Christopher M. Plummer ◽  
Luo Wenjun ◽  
Jiyan Pang ◽  
Yongming Chen ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Small Molecule ◽  
Chain Scission ◽  
Side Reactions ◽  
One Pot ◽  
Methyl Vinyl ◽  
Modification Procedure ◽  
Post Modification ◽  
User Friendly ◽  
Villiger Oxidation

The development of “exhaustive” (nearly quantitative) post-modification reactions relies heavily on the efficiency of their corresponding small-molecule protocols. However, the direct translation of existing small-molecule protocols into post-polymerization modifications were often troublesome due to undesired side reactions. For example, the development of an “exhaustive” BaeyerVilliger (BV) post-modification using existing small-molecule BV protocols suffered from a lack of reactivity or significant chain scission. Herein, we demonstrate that a careful re-optimization of a small-molecule transformation on a polymer substrate allowed us to overcome such challenges, thereby enabling an “exhaustive” BV post-polymerization modification. Furthermore, a one-pot copolymerization/“exhaustive” BV post-modification procedure was developed to produce copolymers of vinyl acetate (VAc) and more activated monomers (MAMs) in a convenient and scalable manner. This user-friendly methodology provides a general access to synthetically challenging poly(VAc-co-MAM)s including both statistical and narrow-dispersed block copolymers and could greatly facilitate the exploration of applications with such materials.

scholarly journals “Exhaustive” Baeyer-Villiger Oxidation of Poly(Methyl Vinyl Ketone) and Its Copolymers

2021 ◽  
Author(s):  
Pengfei Ma ◽  
Christopher M. Plummer ◽  
Luo Wenjun ◽  
Jiyan Pang ◽  
Yongming Chen ◽  
...  
Keyword(s):  
Vinyl Acetate ◽  
Chain Scission ◽  
Vinyl Ketone ◽  
Methyl Vinyl Ketone ◽  
One Pot ◽  
Methyl Vinyl ◽  
Modification Procedure ◽  
Post Modification ◽  
User Friendly ◽  
Villiger Oxidation

Poly(vinyl acetate) and its copolymers represent an important class of commodity polymers. However, the preparation of copolymers of vinyl acetate (VAc) and more activated monomers (MAMs) <i>via</i> copolymerization is greatly restricted due to their disparate reactivities. Issues relating to reactivity ratios remain a fundamental challenge in copolymerization. Herein, we describe a post-polymerization modification approach using poly(methyl vinyl ketone-<i>co</i>-MAM)s as substrates to access synthetically challenging poly(VAc-<i>co</i>-MAM)s. Although the direct translations of existing small-molecule Baeyer-Villiger (BV) protocols into a post-polymerization modification method failed, a mechanism-guided multi-parameter optimization on polymer substrates disclosed a set of unique “exhaustive” BV protocols which enabled a nearly quantitative functionalization without obvious chain scission or cross-linking. Furthermore, a one-pot copolymerization/“exhaustive” BV post-modification procedure was developed to produce such copolymers in a convenient and scalable manner. This user-friendly methodology is able to access diverse poly(VAc-<i>co</i>-MAM)s including both statistical and narrow-dispersed block copolymers and could greatly facilitate the exploration of applications with such materials.

scholarly journals “Exhaustive” Baeyer-Villiger Oxidation of Poly(Methyl Vinyl Ketone) and Its Copolymers

2021 ◽  
Author(s):  
Pengfei Ma ◽  
Christopher M. Plummer ◽  
Luo Wenjun ◽  
Jiyan Pang ◽  
Yongming Chen ◽  
...  
Keyword(s):  
Vinyl Acetate ◽  
Chain Scission ◽  
Vinyl Ketone ◽  
Methyl Vinyl Ketone ◽  
One Pot ◽  
Methyl Vinyl ◽  
Modification Procedure ◽  
Post Modification ◽  
User Friendly ◽  
Villiger Oxidation

Poly(vinyl acetate) and its copolymers represent an important class of commodity polymers. However, the preparation of copolymers of vinyl acetate (VAc) and more activated monomers (MAMs) <i>via</i> copolymerization is greatly restricted due to their disparate reactivities. Issues relating to reactivity ratios remain a fundamental challenge in copolymerization. Herein, we describe a post-polymerization modification approach using poly(methyl vinyl ketone-<i>co</i>-MAM)s as substrates to access synthetically challenging poly(VAc-<i>co</i>-MAM)s. Although the direct translations of existing small-molecule Baeyer-Villiger (BV) protocols into a post-polymerization modification method failed, a mechanism-guided multi-parameter optimization on polymer substrates disclosed a set of unique “exhaustive” BV protocols which enabled a nearly quantitative functionalization without obvious chain scission or cross-linking. Furthermore, a one-pot copolymerization/“exhaustive” BV post-modification procedure was developed to produce such copolymers in a convenient and scalable manner. This user-friendly methodology is able to access diverse poly(VAc-<i>co</i>-MAM)s including both statistical and narrow-dispersed block copolymers and could greatly facilitate the exploration of applications with such materials.

scholarly journals Precise Synthesis and Thin Film Self-Assembly of PLLA-b-PS Bottlebrush Block Copolymers

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1412
Author(s):  
Eunkyung Ji ◽  
Cian Cummins ◽  
Guillaume Fleury
Keyword(s):  
Thin Film ◽  
Block Copolymers ◽  
Self Assembly ◽  
Ring Opening ◽  
Periodic Structures ◽  
One Pot ◽  
Ordered Structures ◽  
Carbonyl Chloride ◽  
Thin Film Patterning ◽  
Nanoporous Templates

The ability of bottlebrush block copolymers (BBCPs) to self-assemble into ordered large periodic structures could greatly expand the scope of photonic and membrane technologies. In this paper, we describe a two-step synthesis of poly(l-lactide)-b-polystyrene (PLLA-b-PS) BBCPs and their rapid thin-film self-assembly. PLLA chains were grown from exo-5-norbornene-2-methanol via ring-opening polymerization (ROP) of l-lactide to produce norbornene-terminated PLLA. Norbonene-terminated PS was prepared using anionic polymerization followed by a termination reaction with exo-5-norbornene-2-carbonyl chloride. PLLA-b-PS BBCPs were prepared from these two norbornenyl macromonomers by a one-pot sequential ring opening metathesis polymerization (ROMP). PLLA-b-PS BBCPs thin-films exhibited cylindrical and lamellar morphologies depending on the relative block volume fractions, with domain sizes of 46–58 nm and periodicities of 70–102 nm. Additionally, nanoporous templates were produced by the selective etching of PLLA blocks from ordered structures. The findings described in this work provide further insight into the controlled synthesis of BBCPs leading to various possible morphologies for applications requiring large periodicities. Moreover, the rapid thin film patterning strategy demonstrated (>5 min) highlights the advantages of using PLLA-b-PS BBCP materials beyond their linear BCP analogues in terms of both dimensions achievable and reduced processing time.

scholarly journals Broccoli Fluorets: Split Aptamers as a User-Friendly Fluorescent Toolkit for Dynamic RNA Nanotechnology

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3178 ◽  
Author(s):  
Morgan Chandler ◽  
Tatiana Lyalina ◽  
Justin Halman ◽  
Lauren Rackley ◽  
Lauren Lee ◽  
...  
Keyword(s):  
Real Time ◽  
Logic Gates ◽  
Rna Aptamers ◽  
One Pot ◽  
Rna Nanotechnology ◽  
Close Proximity ◽  
Direct Tracking ◽  
Displacement Approach ◽  
User Friendly ◽  
In Cells

RNA aptamers selected to bind fluorophores and activate their fluorescence offer a simple and modular way to visualize native RNAs in cells. Split aptamers which are inactive until the halves are brought within close proximity can become useful for visualizing the dynamic actions of RNA assemblies and their interactions in real time with low background noise and eliminated necessity for covalently attached dyes. Here, we design and test several sets of F30 Broccoli aptamer splits, that we call fluorets, to compare their relative fluorescence and physicochemical stabilities. We show that the splits can be simply assembled either through one-pot thermal annealing or co-transcriptionally, thus allowing for direct tracking of transcription reactions via the fluorescent response. We suggest a set of rules that enable for the construction of responsive biomaterials that readily change their fluorescent behavior when various stimuli such as the presence of divalent ions, exposure to various nucleases, or changes in temperature are applied. We also show that the strand displacement approach can be used to program the controllable fluorescent responses in isothermal conditions. Overall, this work lays a foundation for the future development of dynamic systems for molecular computing which can be used to monitor real-time processes in cells and construct biocompatible logic gates.

ChemInform Abstract: One-Pot Synthesis of α-Methyl Vinyl Sulfones from Ethyl Phenyl Sulfones.

ChemInform ◽  
2010 ◽  
Vol 31 (22) ◽  
pp. no-no
Author(s):  
Jae Wook Lee ◽  
Chi-Wan Lee ◽  
Jin Hang Jung ◽  
Dong Young Oh
Keyword(s):  
One Pot ◽  
Methyl Vinyl ◽  
One Pot Synthesis

Amphiphilic Diblock Copolymers of Poly(glycidol) with Biodegradable Polyester/Polycarbonate. Organocatalytic One-Pot ROP and Self-Assembling Property

2021 ◽  
Author(s):  
Tingyu He ◽  
Atsushi Narumi ◽  
Yanqiu Wang ◽  
Liang Xu ◽  
Shin-ichiro Sato ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Diblock Copolymers ◽  
Amphiphilic Block Copolymers ◽  
Synthetic Method ◽  
Biodegradable Polyester ◽  
One Pot ◽  
Self Assembling ◽  
Amphiphilic Diblock Copolymers

A synthetic method for a series of poly(glycidol) (PG)-based amphiphilic block copolymers is presented with an emphasis on the catalyst switch method from an organic superbase (t-Bu-P4) to another with...

Replacing sulfonate by carboxylate: application of pyridyliminocarboxylato copper(II) complexes in rac-lactide polymerization and Chan–Evans–Lam coupling

2019 ◽  
Vol 97 (3) ◽  
pp. 178-190 ◽  
Author(s):  
Valérie Hardouin Duparc ◽  
Clémentine Dimeck ◽  
Frank Schaper
Keyword(s):  
Molecular Sieves ◽  
Weight Control ◽  
Phenylboronic Acid ◽  
Side Reactions ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
One Pot ◽  
X Ray ◽  
Induction Periods ◽  
Lactide Polymerization

Copper(II) complexes carrying pyridylmethyleneaminobenzoate or –propanoate ligands, LCuX, were prepared in one-pot reactions from pyridinecarboxaldehyde, aminobenzoic acid or β-alanine, and CuX2 (X = Cl, NO3, OAc, or OTf). All complexes were characterized by single-crystal X-ray diffraction studies and formed either dimers, tetramers, or coordination polymers. Attempted preparation of the respective alkoxide complexes, LCu(OR), was unsuccessful, but use of LCuX/NaOMe mixtures in rac-lactide polymerization indicated under some conditions coordination–insertion polymerization via a copper alkoxide as the mechanism. The complexes performed poorly in rac-lactide polymerization, showing low activities (12 h to completion at 140 °C), low to moderate heterotacticity (Pr = 0.6–0.8), and poor polymer molecular weight control (intramolecular transesterification). They were competent catalysts for Chan–Evans–Lam couplings with phenylboronic acid, without any indication of side reactions such as deboration or aryl homocoupling. The complexes were active in undried methanol, without addition of base, ligand, or molecular sieves. Aniline, n-octylamine, and cyclohexylamine were coupled quantitatively under identical reaction conditions. There is only little influence of the anion on activities (less than a factor of 2) but a strong influence on induction periods. The complexes were not active in CEL coupling with alcohols, phenols, or alkylboronic acids.

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