The role of ligand redox non-innocence in ring-opening polymerization reactions catalysed by bis(imino)pyridine iron alkoxide complexes

2017 ◽  
Vol 46 (38) ◽  
pp. 12971-12980 ◽  
Author(s):  
K. R. Delle Chiaie ◽  
A. B. Biernesser ◽  
M. A. Ortuño ◽  
B. Dereli ◽  
D. A. Iovan ◽  
...  
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Oxidation States ◽  
Polymerization Catalysts ◽  
Iron Based

The reactivity of iron-based ring opening polymerization catalysts is compared when the catalyst is in three different oxidation states.

A switchable dimeric yttrium complex and its three catalytic states in ring opening polymerization

2021 ◽  
Author(s):  
Shijie Deng ◽  
Paula L. Diaconescu
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Oxidation States ◽  
Cyclic Esters

A dimeric yttrium phenoxide complex can be oxidized in a stepwise fashion to access three oxidation states. The three states show different activity in the ring opening polymerization of cyclic esters and epoxides.

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.

Ring Opening Polymerization of ε-Caprolactone Catalyzed with Magnesium Lactate

2009 ◽  
Vol 610-613 ◽  
pp. 1208-1210 ◽  
Author(s):  
Lian Liu ◽  
Zhi Yong Wei ◽  
Pei Wang ◽  
Min Qi
Keyword(s):  
Nmr Spectroscopy ◽  
Reaction Temperature ◽  
13C Nmr ◽  
Ring Opening ◽  
Synthesis Method ◽  
13C Nmr Spectroscopy ◽  
Ring Opening Polymerization ◽  
Moderate Activity ◽  
Lactide Copolymers

The aim of this paper is to present a synthesis method of poly(ε-caprolactone) by the ring opening polymerization of ε-caprolactone catalyzed with nontoxic magnesium lactate. The results indicated that Mg(Lac)2 is a catalyst with moderate activity for the polymerization of ε-caprolactone. Effects of the catalyst and reaction temperatures on the microstructure of the ε-caprolactone and L-lactide copolymers were investigated by means of 13C-NMR spectroscopy. An increase in the reaction temperature enhances the role of transesterification and the extent of randomness.

The Role of Nitrogen Donors in Zinc Catalysts for Lactide Ring-Opening Polymerization

2016 ◽  
Vol 55 (18) ◽  
pp. 9445-9453 ◽  
Author(s):  
Tannaz Ebrahimi ◽  
Emiliya Mamleeva ◽  
Insun Yu ◽  
Savvas G. Hatzikiriakos ◽  
Parisa Mehrkhodavandi
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Nitrogen Donors

Synthesis and Structures of Tridentate Ketoiminate Zinc Complexes That Act As l-Lactide Ring-Opening Polymerization Catalysts

2012 ◽  
Vol 31 (11) ◽  
pp. 4133-4141 ◽  
Author(s):  
Courtney C. Roberts ◽  
Brandon R. Barnett ◽  
David B. Green ◽  
Joseph M. Fritsch
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Zinc Complexes ◽  
Polymerization Catalysts

The Role of Alkoxide Initiator, Spin State, and Oxidation State in Ring-Opening Polymerization of ε-Caprolactone Catalyzed by Iron Bis(imino)pyridine Complexes

2018 ◽  
Vol 57 (4) ◽  
pp. 2064-2071 ◽  
Author(s):  
Manuel A. Ortuño ◽  
Büsra Dereli ◽  
Kayla R. Delle Chiaie ◽  
Ashley B. Biernesser ◽  
Miao Qi ◽  
...  
Keyword(s):  
Oxidation State ◽  
Spin State ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Pyridine Complexes

Ring-opening polymerization of ethylene carbonate using ionic liquids as catalysts

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiancheng Zhou ◽  
Ling Cheng ◽  
Dongfang Wu
Keyword(s):  
Ionic Liquids ◽  
Ring Opening ◽  
Ethylene Carbonate ◽  
Molar Fraction ◽  
Reaction System ◽  
Monomer Conversion ◽  
Catalytic Performance ◽  
Ring Opening Polymerization ◽  
Polymerization Catalysts ◽  
Chain Cleavage

AbstractThe ring-opening polymerization of ethylene carbonate was examined using ionic liquids, 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF4) and 1-butyl-3-methylimidazolium chlorozincate ([bmim]Cl-(ZnCl2)x), as polymerization catalysts. It was shown that the polymerization was accompanied with decarboxylation and chain cleavage reaction. As the reaction time increased, the monomer conversion increased and the content of ethylene carbonate units in the resultant polymer decreased, while the polymer molecular weight increased at first, reached a maximum and then decreased. It was also found that not only the polymerizing activity of the [bmim]Cl-(ZnCl2)x but also its performance for suppressing the decarboxylation and chain cleavage increased with the molar fraction of ZnCl2. It was deduced that the catalytic performance of ionic liquids mainly depended on their inorganic anions and that the larger the amount of these anions in the reaction system, the better the catalytic performance. The polymerizing activity of ionic liquids was much higher than conventional catalysts often used for the polymerization of ethylene carbonate.

scholarly journals Towards a selective synthetic route for cobalt amino acid complexes and their application in ring opening polymerization of rac-lactide

RSC Advances ◽  
2021 ◽  
Vol 11 (27) ◽  
pp. 16326-16338
Author(s):  
Andrés Castro Ruiz ◽  
Krishna K. Damodaran ◽  
Sigridur G. Suman
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Oxidation States ◽  
Synthetic Route ◽  
Coordination Properties ◽  
Amino Acid Complexes ◽  
Ligand Coordination

Catalysts based on Co, amino acids, and 2,2-bipyridine present an attractive and economic alternative in ring opening polymerization, and possess advantageous ligand coordination properties combined with a variety of accessible oxidation states and coordination geometries.

Sm based initiators for the ring-opening polymerization of L-lactide

e-Polymers ◽  
2001 ◽  
Vol 1 (1) ◽  
Author(s):  
Seema Agarwal ◽  
Marc Karl ◽  
Kurt Dehnicke ◽  
Andreas Greiner
Keyword(s):  
Carbon Atom ◽  
Optical Activity ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Optically Active ◽  
Polymerization Catalysts ◽  
Time Intervals ◽  
Chiral Carbon

AbstractRing-opening polymerizations of L-lactide were carried out in the presence of Sm(II) (SmI2/Sm) and the Sm(III) complex [Sm(m-Cl){N(SiMe3)2}2(THF)]2 (Me: CH3, THF: tetrahydrofuran). The polymerizations were performed using different mole ratios of monomer to initiator and for different time intervals. The complexes were found to be active polymerization catalysts and led to the synthesis of semicrystalline, optically active poly(L-lactide) retaining about 95.5% of the optical activity. This shows that - with the initiator systems used - polymerization proceeds with the retention of configuration at the chiral carbon atom.

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