A computational insight into a metal mediated pathway for the ring-opening polymerization (ROP) of lactides by an ionic {(NHC)2Ag}+X− (X = halide) type N-heterocyclic carbene (NHC) complex

2011 ◽  
Vol 40 (39) ◽  
pp. 10156 ◽  
Author(s):  
Raji Stephen ◽  
Raghavan B. Sunoj ◽  
Prasenjit Ghosh
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Insight Into

A New Insight Into the Mechanism of the Ring-Opening Polymerization of Trimethylene Carbonate Catalyzed by Methanesulfonic Acid

2012 ◽  
Vol 214 (1) ◽  
pp. 85-93 ◽  
Author(s):  
João M. Campos ◽  
Maria R. Ribeiro ◽  
Maria F. Ribeiro ◽  
Alain Deffieux ◽  
Frédéric Peruch
Keyword(s):  
Ring Opening ◽  
Methanesulfonic Acid ◽  
Ring Opening Polymerization ◽  
Trimethylene Carbonate ◽  
Insight Into

Multiblock silicones, 1 Vinyl functionalized polydimethylsiloxane a

e-Polymers ◽  
2003 ◽  
Vol 3 (1) ◽  
Author(s):  
Carine Ivanenko ◽  
Catherine Maitre ◽  
François Ganachaud ◽  
Patrick Hémery
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Multiblock Copolymers ◽  
Chain Reactions ◽  
Anionic Ring ◽  
Interface Propagation ◽  
Dispersed Media ◽  
Insight Into

Abstract The first part of this series is devoted to the preparation of vinyl functionalized multiblock silicones by the process of anionic ring opening polymerization in miniemulsion. The advantage of working in dispersed media is that different scales of reactivities are found between one-chain reactions, taking place at the interface (propagation, backbiting), and two-chain reactions, located in the bulk of the particles (polycondensation and intermolecular redistribution). First, homopolymerizations of octamethylcyclotetrasiloxane (D4) and tetramethyltetravinylcyclotetrasiloxane (D4 V) were carried out and compared, focusing specifically on the rates of polymerization, backbiting and polycondensation processes. Copolymerization of D4 with D4 V then gave insight into the extent of mixed cycles’ formation and particularly how to avoid these. On this basis, recipes were carefully selected so that homopolymerization and scarce co-polycondensation and redistribution progress at the expense of backbiting reactions and thus multiblock copolymers are formed, the microstructure of which was confirmed with 29Si NMR.

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.

scholarly journals Back Cover: Insight into the Thermal Ring-Opening Polymerization of Phospha[1]ferrocenophanes (Chem. Eur. J. 47/2016)

2016 ◽  
Vol 22 (47) ◽  
pp. 17048-17048 ◽  
Author(s):  
Elaheh Khozeimeh Sarbisheh ◽  
Jose Esteban Flores ◽  
Jianfeng Zhu ◽  
Jens Müller
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Back Cover ◽  
Insight Into

Theoretical insight into the redox-switchable activity of group 4 metal complexes for the ring-opening polymerization of ε-caprolactone

2020 ◽  
Vol 7 (4) ◽  
pp. 961-971 ◽  
Author(s):  
Xiaowei Xu ◽  
Gen Luo ◽  
Zhaomin Hou ◽  
Paula L. Diaconescu ◽  
Yi Luo
Keyword(s):  
Dft Calculations ◽  
Metal Complexes ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Lewis Acidity ◽  
Group 4 ◽  
Catalytic Metal ◽  
Group 4 Metal ◽  
Theoretical Insight ◽  
Insight Into

DFT calculations indicate that the Lewis acidity of the catalytic metal center M (Ti, Zr, Hf) explains the redox-switchable activity observed for the ring-opening polymerization of ε-caprolactone by ferrocene derived metal complexes.

Insight into the Thermal Ring-Opening Polymerization of Phospha[1]ferrocenophanes

2016 ◽  
Vol 22 (47) ◽  
pp. 16838-16849 ◽  
Author(s):  
Elaheh Khozeimeh Sarbisheh ◽  
Jose Esteban Flores ◽  
Jianfeng Zhu ◽  
Jens Müller
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Insight Into

scholarly journals Insight into the synthesis of N-methylated polypeptides

2020 ◽  
Vol 11 (43) ◽  
pp. 6919-6927
Author(s):  
Christian Muhl ◽  
Lydia Zengerling ◽  
Jonathan Groß ◽  
Paul Eckhardt ◽  
Till Opatz ◽  
...  
Keyword(s):  
Amino Acids ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Insight Into

The ring-opening polymerization of α-substituted N-methylated N-carboxy anhydrides is reported. The polymerization was tested using various amino acids and initiators, and was found to be limited by the steric demand of N-methylated compared to conventional amino acids.

An Insight into the Anionic Ring-Opening Polymerization with Tetrabutylammonium Azide for the Generation of Pure Cyclic Poly(glycidyl phenyl ether)

2018 ◽  
Vol 51 (7) ◽  
pp. 2447-2455 ◽  
Author(s):  
Jordan Ochs ◽  
Antonio Veloso ◽  
Daniel E. Martínez-Tong ◽  
Angel Alegria ◽  
Fabienne Barroso-Bujans
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Phenyl Ether ◽  
Anionic Ring ◽  
Insight Into

Theoretical insight into the opposite redox activity of iron complexes toward the ring opening polymerization of lactide and epoxide

2021 ◽  
Author(s):  
Xiaowei Xu ◽  
Han Lu ◽  
Gen Luo ◽  
Xiaohui Kang ◽  
Yi Luo
Keyword(s):  
Ring Opening ◽  
Iron Complexes ◽  
Ring Opening Polymerization ◽  
Redox Activity ◽  
Cyclohexene Oxide ◽  
Theoretical Insight ◽  
Insight Into

The origin of opposite reactivity in the ring-opening polymerization of lactide (LA) and cyclohexene oxide (CHO) catalyzed by redox-switchable bis(imino)pyridine iron complexes has been computationally elucidated.

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