Ionic hydrogen bond donor organocatalyst for fast living ring-opening polymerization

2016 ◽  
Vol 7 (2) ◽  
pp. 339-349 ◽  
Author(s):  
Xu Zhi ◽  
Jingjing Liu ◽  
Zhenjiang Li ◽  
Huiying Wang ◽  
Xin Wang ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Ring Opening ◽  
Positive Charge ◽  
Ring Opening Polymerization ◽  
Hydrogen Bond Donor

A positive charge enhanced H-bond donor combined with H-bond acceptor as a bifunctional organocatalyst enables fast living ring-opening polymerization of lactide.

Tripodal hydrogen bond donor binding with sulfonic acid enables ring-opening polymerization

2016 ◽  
Vol 7 (7) ◽  
pp. 1368-1374 ◽  
Author(s):  
Xiaopei Li ◽  
Qiguo Zhang ◽  
Zhenjiang Li ◽  
Songquan Xu ◽  
Chengxu Zhao ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Ring Opening ◽  
Sulfonic Acid ◽  
Ring Opening Polymerization ◽  
Cyclic Ester ◽  
Cyclic Carbonates ◽  
Hydrogen Bond Donor ◽  
Acidic Catalysis

The first Brønsted acidic catalysis platform workable in all of the three major types of cyclic ester monomers including lactides, cyclic carbonates, and lactones, is described in this paper.

Aminoethylimidazole ionic liquid grafted MIL-101-NH2 heterogeneous catalyst for conversion of CO2 and epoxide without solvent and cocatalyst

2021 ◽  
Author(s):  
Chenglong Bao ◽  
Yichen Jiang ◽  
Liyan Zhao ◽  
Dazhi Li ◽  
Ping Xu ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Ionic Liquid ◽  
Lewis Acid ◽  
Ring Opening ◽  
Synergistic Effects ◽  
Acid Sites ◽  
Epoxide Ring ◽  
Hydrogen Bond Donor ◽  
Lewis Acid Sites ◽  
Epoxide Ring Opening

Besides the activation of CO2 by Lewis basic groups, the synergistic effects of Lewis acid sites (or hydrogen bond donor) together with halogen nucleophilic anions to activate epoxide ring opening...

scholarly journals Cooperative Hydrogen-Bond Pairing in Organocatalytic Ring-Opening Polymerization

2014 ◽  
Vol 47 (21) ◽  
pp. 7463-7468 ◽  
Author(s):  
Oleg I. Kazakov ◽  
Partha P. Datta ◽  
Meghedi Isajani ◽  
Elizabeth T. Kiesewetter ◽  
Matthew K. Kiesewetter
Keyword(s):  
Hydrogen Bond ◽  
Ring Opening ◽  
Ring Opening Polymerization

A squaramide and tertiary amine: an excellent hydrogen-bonding pair organocatalyst for living polymerization

2015 ◽  
Vol 6 (20) ◽  
pp. 3754-3757 ◽  
Author(s):  
Jingjing Liu ◽  
Cheng Chen ◽  
Zhenjiang Li ◽  
Wenzhuo Wu ◽  
Xu Zhi ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Ambient Temperature ◽  
Tertiary Amine ◽  
Ring Opening ◽  
Living Polymerization ◽  
Ring Opening Polymerization

A hydrogen-bond motif based on a squaramide and sparteine efficiently promoted the ring-opening polymerization of l-lactide at ambient temperature.

Three is company: dual intramolecular hydrogen-bond enabled carboxylic acid active in ring-opening polymerization

2016 ◽  
Vol 7 (5) ◽  
pp. 1111-1120 ◽  
Author(s):  
Jiaxi Xu ◽  
Jingjing Liu ◽  
Zhenjiang Li ◽  
Xiaopei Li ◽  
Cheng Chen ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Carboxylic Acid ◽  
Intramolecular Hydrogen Bond ◽  
Ring Opening ◽  
Active Catalyst ◽  
Ring Opening Polymerization ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Brönsted Acid ◽  
Intramolecular Hydrogen

Dual intramolecular H-bonding made weak Brønsted acid an active catalyst in cationic ring-opening polymerizations.

A Hydrogen Bond Between Linear Tetrapyrrole and Conserved Aspartate Causes the Far-Red Shifted Absorption of Phytochrome Photoreceptors

2020 ◽  
Author(s):  
Egle Maximowitsch ◽  
Tatiana Domratcheva
Keyword(s):  
Hydrogen Bond ◽  
Light Adaptation ◽  
Positive Charge ◽  
Pyrrole Ring ◽  
Md Simulations ◽  
Spectral Shift ◽  
Specific Domain ◽  
Study Guides ◽  
Rational Engineering ◽  
Tuning Mechanism

Photoswitching of phytochrome photoreceptors between red-absorbing (Pr) and far-red absorbing (Pfr) states triggers light adaptation of plants, bacteria and other organisms. Using quantum chemistry, we elucidate the color-tuning mechanism of phytochromes and identify the origin of the Pfr-state red-shifted spectrum. Spectral variations are explained by resonance interactions of the protonated linear tetrapyrrole chromophore. In particular, hydrogen bonding of pyrrole ring D with the strictly conserved aspartate shifts the positive charge towards ring D thereby inducing the red spectral shift. Our MD simulations demonstrate that formation of the ring D–aspartate hydrogen bond depends on interactions between the chromophore binding domain (CBD) and phytochrome specific domain (PHY). Our study guides rational engineering of fluorescent phytochromes with a far-red shifted spectrum.

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