scholarly journals Hydrogen-bond donor and acceptor cooperative catalysis strategy for cyclic dehydration of diols to access O-heterocycles

2021 ◽  
Vol 7 (22) ◽  
pp. eabg0396
Author(s):  
Huan Wang ◽  
Yanfei Zhao ◽  
Fengtao Zhang ◽  
Zhengang Ke ◽  
Buxing Han ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Free Acid ◽  
Hydrogen Bond Donor ◽  
Metal Free ◽  
Mild Conditions ◽  
Cooperative Catalysis ◽  
Donor And Acceptor ◽  
Green Strategy ◽  
High Yields ◽  
Better Than

Dehydrative cyclization of diols to O-heterocycles is attractive, but acid and/or metal-based catalysts are generally required. Here, we present a hydrogen-bond donor and acceptor cooperative catalysis strategy for the synthesis of O-heterocycles from diols in ionic liquids [ILs; e.g., 1-hydroxyethyl-3-methyl imidazolium trifluoromethanesulfonate ([HO-EtMIm][OTf])] under metal-free, acid-free, and mild conditions. [HO-EtMIm][OTf] is tolerant to a wide diol scope, shows performance even better than H2SO4, and affords a series of O-heterocycles including tetrahydrofurans, tetrahydropyrans, morpholines, dioxanes, and thioxane in high yields. Mechanism investigation indicates that the IL cation and anion serve as hydrogen-bond donor and acceptor, respectively, to activate the C─O and O─H bonds of alcohol via hydrogen bonds, which synergistically catalyze dehydrative cyclization of diols to O-heterocycles. Notably, the products could be spontaneously separated after reaction because of their immiscibility with the IL, and the IL could be recycled. This green strategy has great potential for application in industry.

scholarly journals When are two hydrogen bonds better than one? Accurate first-principles models explain the balance of hydrogen bond donors and acceptors found in proteins

2021 ◽  
Author(s):  
Vyshnavi Vennelakanti ◽  
Helena W. Qi ◽  
Rimsha Mehmood ◽  
Heather J. Kulik
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
High Resolution ◽  
Hydrogen Bonds ◽  
First Principles ◽  
Crystal Structure Analysis ◽  
Hydrogen Bond Donor ◽  
Donor And Acceptor ◽  
Stabilizing Effect ◽  
Better Than

Correlated wavefunction theory predicts and high-resolution crystal structure analysis confirms the important, stabilizing effect of simultaneous hydrogen bond donor and acceptor interactions in proteins.

Aliphatic Carboxylic Acid as Hydrogen-Bond Donor for Converting CO2 and Epoxide into Cyclic Carbonate under Mild Conditions

2021 ◽  
Author(s):  
Zheng Wang ◽  
Yajun Wang ◽  
Qianjie Xie ◽  
Zhiying Fan ◽  
Yehua Shen
Keyword(s):  
Hydrogen Bond ◽  
Carboxylic Acid ◽  
Value Added ◽  
Cyclic Carbonate ◽  
Hydrogen Bond Donor ◽  
Title Reaction ◽  
Aliphatic Carboxylic Acid ◽  
Mild Conditions ◽  
Atmospheric Carbon

The coupling of CO2 and epoxide is promising way to reduce atmospheric carbon by converting it into value-added cyclic carbonate. Pursuing efficient catalysts is highly attractive for the title reaction....

Hydrogen bond donor functionalized poly(ionic liquid)s for efficient synergistic conversion of CO2 to cyclic carbonates

2020 ◽  
Author(s):  
Haibin Gou ◽  
Xifei Ma ◽  
Qian Su ◽  
Lei Liu ◽  
Ting Ying ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Ionic Liquid ◽  
Value Added ◽  
Pivotal Role ◽  
Cyclic Carbonates ◽  
Hydrogen Bond Donor ◽  
Metal Free ◽  
Recyclable Catalysts ◽  
Poly Ionic Liquid ◽  
Value Added Products

The development of metal-free, high effective and recyclable catalysts plays a pivotal role in transforming CO2 into high value-added products such as cyclic carbonates. In this paper, we have introduced...

scholarly journals Machine learning models for hydrogen bond donor and acceptor strengths using large and diverse training data generated by first-principles interaction free energies

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Christoph A. Bauer ◽  
Gisbert Schneider ◽  
Andreas H. Göller
Keyword(s):  
Machine Learning ◽  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Training Data ◽  
Free Energies ◽  
Hydrogen Bond Donor ◽  
Chemical Application ◽  
Hydrogen Bond Acceptor ◽  
Donor And Acceptor ◽  
Target Values

Abstract We present machine learning (ML) models for hydrogen bond acceptor (HBA) and hydrogen bond donor (HBD) strengths. Quantum chemical (QC) free energies in solution for 1:1 hydrogen-bonded complex formation to the reference molecules 4-fluorophenol and acetone serve as our target values. Our acceptor and donor databases are the largest on record with 4426 and 1036 data points, respectively. After scanning over radial atomic descriptors and ML methods, our final trained HBA and HBD ML models achieve RMSEs of 3.8 kJ mol−1 (acceptors), and 2.3 kJ mol−1 (donors) on experimental test sets, respectively. This performance is comparable with previous models that are trained on experimental hydrogen bonding free energies, indicating that molecular QC data can serve as substitute for experiment. The potential ramifications thereof could lead to a full replacement of wetlab chemistry for HBA/HBD strength determination by QC. As a possible chemical application of our ML models, we highlight our predicted HBA and HBD strengths as possible descriptors in two case studies on trends in intramolecular hydrogen bonding.

The hydrogen bond donor and acceptor ability of thioformic acid

2011 ◽  
Vol 22 (5) ◽  
pp. 1015-1030 ◽  
Author(s):  
Damanjit Kaur ◽  
Ritika Sharma ◽  
Darpandeep Aulakh
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bond Donor ◽  
Donor And Acceptor

Synthesis and preliminary bioactivity evaluation of new pregnane brassinosteroid-like compounds

2005 ◽  
Vol 83 (8) ◽  
pp. 1084-1092 ◽  
Author(s):  
Daniel G Rivera ◽  
Francisco Coll
Keyword(s):  
Hydrogen Bond ◽  
Plant Growth ◽  
Hypocotyl Elongation ◽  
Hydrogen Bond Donor ◽  
Donor And Acceptor ◽  
Plant Growth Promoting ◽  
Plant Growth Promoting Activity ◽  
Growth Promoting ◽  
Cotyledon Expansion

Seven new pregnane compounds bearing some representative A- and B-ring brassinosteroid functions, as well as hydrogen bond donor and acceptor ones on the D ring, were efficiently synthesized. The obtained compounds did not show remarkable plant growth-promoting activity in the radish hypocotyl elongation and cotyledon expansion bioassays, however, introducing oxygen and amino functions on the D ring led to an enhancement of the bioactivity. The 16β-functionalized pregnane brassinosteroid-like compounds were slightly more active than the 16α-functionalized ones.Key words: steroids, brassinosteroids, pregnane analogues.

C–H⋯S interaction exhibits all the characteristics of conventional hydrogen bonds

2020 ◽  
Vol 22 (31) ◽  
pp. 17482-17493 ◽  
Author(s):  
Sanat Ghosh ◽  
Pragya Chopra ◽  
Sanjay Wategaonkar
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Hydrogen Bond Donor ◽  
Donor And Acceptor

This is a tale of a pair of a hydrogen bond donor and acceptor, namely the CH donor and sulphur acceptor, neither of which is a conventional hydrogen bond participant.

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