Living polymerization of acrylamides catalysed by N-heterocyclic olefin-based Lewis pairs

2019 ◽  
Vol 10 (26) ◽  
pp. 3597-3603 ◽  
Author(s):  
Huaiyu Wang ◽  
Qianyi Wang ◽  
Jianghua He ◽  
Yuetao Zhang

Living/controlled polymerization of acrylamides achieved by a Lewis pair composed of an N-heterocyclic olefin as a Lewis base and triphenylaluminum as a Lewis acid.

2021 ◽  
Vol 12 (38) ◽  
pp. 5548-5555
Author(s):  
Yun Bai ◽  
Huaiyu Wang ◽  
Jianghua He ◽  
Yuetao Zhang

The frustrated Lewis pair composed of an organophosphorus(iii) superbase and a bulky organoaluminum Lewis acid promoted the living/controlled polymerization of naturally renewable butyrolactone-based vinylidenes.


2016 ◽  
Vol 52 (64) ◽  
pp. 9949-9952 ◽  
Author(s):  
Leif A. Körte ◽  
Sebastian Blomeyer ◽  
Shari Heidemeyer ◽  
Andreas Mix ◽  
Beate Neumann ◽  
...  

The doubly Lewis-acid functionalised aniline PhN[(CH2)3B(C6F5)2]2 features two competing boron functions in fast exchange for binding to the central Lewis base. In contrast to the mono acid-functionalised PhMeN[(CH2)3B(C6F5)2], it is an active frustrated Lewis pair.


2012 ◽  
Vol 84 (11) ◽  
pp. 2203-2217 ◽  
Author(s):  
Gerhard Erker

The chemistry of some reactive frustrated Lewis pairs (FLPs) is reported. This includes intramolecular P/B and N/B FLPs, some of which were used as catalysts for the hydrogenation of electron-rich olefin substrates. Some advanced intermolecular FLPs are reported, which includes systems derived from very bulky alkenyl boranes obtained from 1,1-carboboration reactions of 1-alkynes with tris(pentafluorophenyl)borane. Some such systems activate dihydrogen and transfer the resulting proton/hydride pair even to some electron-poor alkynes. Eventually, we report on the reaction of our intramolecular ethylene-bridged P/B FLP with nitric oxide (NO). N,B-addition of the P-Lewis base/B-Lewis acid combination is observed to form a new type of a persistent aminoxyl radical. Some of the chemistry of the new FLP-NO radicals is presented and discussed.


2015 ◽  
Vol 13 (12) ◽  
pp. 3633-3647 ◽  
Author(s):  
Adhikesavan Harikrishnan ◽  
Jayakumar Sanjeevi ◽  
Chinnasamy Ramaraj Ramanathan

Lewis acid (with or without a Lewis base) enhances the electrophilicity of aldehydes to react with aromatic π-nucleophiles and generate carbinols.


2021 ◽  
Author(s):  
Fang Ge ◽  
Sun Li ◽  
Zhe Wang ◽  
Wenzhong Zhang ◽  
Xiaowu Wang

Developing different synthetic approaches to realize controlled or living polymerization are aspirational to achieve polymers with defined molecular weight, narrow molecular weight distribution and unambiguous structures by polymer chemists. Herein,...


Author(s):  
R. Morris Bullock ◽  
Geoffrey M. Chambers

This perspective examines frustrated Lewis pairs (FLPs) in the context of heterolytic cleavage of H 2 by transition metal complexes, with an emphasis on molecular complexes bearing an intramolecular Lewis base. FLPs have traditionally been associated with main group compounds, yet many reactions of transition metal complexes support a broader classification of FLPs that includes certain types of transition metal complexes with reactivity resembling main group-based FLPs. This article surveys transition metal complexes that heterolytically cleave H 2 , which vary in the degree that the Lewis pairs within these systems interact. Many of the examples include complexes bearing a pendant amine functioning as the base with the metal functioning as the hydride acceptor. Consideration of transition metal compounds in the context of FLPs can inspire new innovations and improvements in transition metal catalysis. This article is part of the themed issue ‘Frustrated Lewis pair chemistry’.


2016 ◽  
Vol 6 (3) ◽  
pp. 882-889 ◽  
Author(s):  
Kai C. Szeto ◽  
Wissam Sahyoun ◽  
Nicolas Merle ◽  
Jessica Llop Castelbou ◽  
Nicolas Popoff ◽  
...  

Supported Lewis acid/base systems based have been prepared and characterized.


2014 ◽  
Vol 13 (01) ◽  
pp. 1350076 ◽  
Author(s):  
Bing Liu ◽  
Daxi Wang ◽  
Zhongxue Wang ◽  
Zhen Zhao ◽  
Yu Chen ◽  
...  

The geometries, vibrational frequencies, electronic properties and reactivity of potassium supported on SBA-15 have been theoretically investigated by the density functional theory (DFT) method. The structural model of the potassium supported on SBA-15 was constructed based on our previous work [Wang ZX, Wang DX, Zhao Z, Chen Y, Lan J, A DFT study of the structural units in SBA-15 mesoporous molecular sieve, Comput. Theor. Chem.963, 403, 2011]. This paper is the extension of our previous work. The most favored location of potassium atom was obtained by the calculation of substitution energy. The calculated vibrational frequencies of K /SBA-15 are in good agreement with the experimental results. By analyzing the properties of electronic structure, we found that the O atom of Si - O (2)- K group acts as the Lewis base center and the K atom acts as the Lewis acid center. The reactivity of K /SBA-15 was investigated by calculating the activation of oxygen molecule. The oxygen molecule can be activated by K /SBA-15 with an energy barrier of 103.2 kJ/mol. In the final state, the activated oxygen atoms become new Lewis acid centers, which are predicted to act as the active sites in the catalytic reactions. This study provides a deep insight into the properties of supported potassium catalysts and offers fundamental information for further research.


2006 ◽  
Vol 691 (3) ◽  
pp. 538
Author(s):  
Samuel W. Coghlan ◽  
Richard L. Giles ◽  
Judith A.K. Howard ◽  
Leonard G.F. Patrick ◽  
Michael R. Probert ◽  
...  

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