Interplay of Steric Hindrance and Hydrogen Bonding To Restrict Mono-O-substitutedp-tert-Butylcalix[6]arenes in Cone Conformation

1998 ◽  
Vol 63 (4) ◽  
pp. 1079-1085 ◽  
Author(s):  
J. Oriol Magrans ◽  
Ana M. Rincón ◽  
Félix Cuevas ◽  
Javier López-Prados ◽  
Pedro M. Nieto ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Steric Hindrance ◽  
Cone Conformation

scholarly journals Effects of alkanolamine solvents on the aggregation states of reactive dyes in concentrated solutions and the properties of the solutions

RSC Advances ◽  
2021 ◽  
Vol 11 (18) ◽  
pp. 10929-10934
Author(s):  
Chuangui Cao ◽  
Zhihui Zhao ◽  
Yong Qi ◽  
Hui Peng ◽  
Kuanjun Fang ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Steric Hindrance ◽  
Reactive Dyes ◽  
Concentrated Solutions ◽  
Weak Hydrogen Bonding ◽  
Dye Aggregation

The solvent, DEA, reduces the dye aggregation that may be caused by the weak hydrogen bonding and relatively smaller steric hindrance effect.

scholarly journals Kinetics of Free Radical Polymerization of N-Substituted Amides and Their Structural Implications

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Anca Aldea ◽  
Ana-Maria Albu ◽  
Alina Nicolescu ◽  
Victorita Tecuceanu
Keyword(s):  
Hydrogen Bonding ◽  
Free Radical ◽  
Nitrogen Atom ◽  
Steric Hindrance ◽  
Solvent Polarity ◽  
Hydrogen Bonding Interaction ◽  
H Nmr ◽  
Bonding Interaction ◽  
Kinetics Of ◽  
C Nmr

Two N-substituted amides (N-acryloyl morpholine and N-methyl-N-vinylacetamide) were polymerized in different solvents using radical initiator. The tacticity of obtained polymers was determined by 400 MHz1H-NMR and13C-NMR. At a given temperature, the syndiotacticity increased with increasing the solvent polarity. This solvent effect may be related to the hydrogen bonding interaction among solvent, monomer, and/or growing species. A peculiar aspect regards the steric hindrance at the nitrogen atom.

Aromatic amides. VII. Steric hindrance to hydrogen bonding in ortho-substituted acetanilides

1972 ◽  
Vol 25 (3) ◽  
pp. 639 ◽  
Author(s):  
BD Andrews ◽  
AJ Poynton ◽  
ID Rae
Keyword(s):  
Hydrogen Bonding ◽  
Magnetic Resonance ◽  
Steric Hindrance ◽  
Proton Magnetic Resonance ◽  
Intramolecular Hydrogen Bonding ◽  
Intramolecular Hydrogen ◽  
Magnetic Resonance Spectra

A series of 2-substituted 3,5-dimethylanilines and their N-acetyl derivatives have been synthesized, and their proton magnetic resonance spectra recorded. Intramolecular hydrogen bonding between the amide N-H and the 2-substituent is disturbed by steric hindrance of the 2-substituent only in the case of the 2-nitro, 2-acetyl, and 2-methoxycarbonyl substituents.

scholarly journals 5,11,17,23-Tetra-tert-butyl-25,27-bis[2-(4-nitrophenoxy)ethoxy]calix[4]arene-26,28-diol acetonitrile tetrasolvate

2009 ◽  
Vol 65 (6) ◽  
pp. o1336-o1337
Author(s):  
Jiu-Mao Yuan ◽  
Yong-Hong Gao ◽  
Jian-Ping Ma ◽  
Dian-Shun Guo
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Dihedral Angles ◽  
Asymmetric Unit ◽  
Cone Conformation ◽  
Compound C ◽  
Butyl Group ◽  
Benzene Rings ◽  
The Mean ◽  
Solvent Molecules

In the crystal structure of the title compound, C60H70N2O10·4CH3CN, the calix[4]arene molecule adopts an open-cone conformation with two intramolecular O—H...O hydrogen bonds. The four benzene rings of the calix[4]arene are twisted to the mean plane defined by four methylene C atoms bridging the benzene rings, with dihedral angles ranging from 57.74 (10) to 65.99 (12)°. Two pendant nitrophenyl rings are nearly perpendicular to each other, the dihedral angle being 70.9 (3)°. The asymmetric unit of the crystal structure contains four acetonitrile solvent molecules, one of which lies in the calix cavity and makes C—H...π interactions and another links with the calix[4]areneviaC—H...O hydrogen bonding. Onetert-butyl group is disordered over two sets of sites, with a 0.736 (13):0.264 (13) occupancy ratio.

A Comparison of the Enamino Carbonyl Conjugation Efficiency for Hydrogen Bonding Formation in Pyridone and Dihydropyridone Systems

2000 ◽  
Vol 55 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Teresa Borowiak ◽  
Irena Wolska ◽  
Artur Korzański ◽  
Wolfgang Milius ◽  
Wolfgang Schnick ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Steric Hindrance ◽  
Crystal Packing ◽  
Intermolecular Hydrogen Bond ◽  
Asymmetric Unit ◽  
Intermolecular Hydrogen Bonds

The crystal structures of two compounds containing enaminone heterodiene systems and forming intermolecular hydrogen bonds N-H·O are reported: 1) 3-ethoxycarbonyl-2-methyl-4-pyridone (hereafter ETPY) and 2) 3-ethoxycarbonyl-2-phenyl-6-methoxycarbonyl-5,6-di-hydro-4-pyridone (hereafter EPPY). The crystal packing is controlled by intermolecular hydro­ gen bonds N-H·O = C connecting the heteroconjugated enaminone groups in infinite chains. In ETPY crystals the intermolecular hydrogen bond involves the heterodienic pathway with the highest π-delocalization that is effective for a very short N·O distance of 2.701(9) Å (average from two molecules in the asymmetric unit). Probably due to the steric hindrance, the hydrogen bond in EPPY is formed following the heterodienic pathway that involves the ester C = O group, although π-delocalization along this pathway is less than that along the pyridone-part pathway resulting in a longer N·O distance of 2.886(3) Å

Stereoselective Aminoiodination of Activated Alkynes with Organoiodine(III) Reagents and Amines via Multiple-Site Functionalization: Access to Iodinated Enamines and N-Aryl Indoles

2019 ◽  
Author(s):  
sagar arepally ◽  
Narenderreddy Katta ◽  
Ajoy Chamuah ◽  
Sharada Duddu. S
Keyword(s):  
Hydrogen Bonding ◽  
Steric Hindrance ◽  
Single Step ◽  
Multiple Site ◽  
Aryl Group ◽  
Mild Conditions ◽  
Reaction Proceeds ◽  
Activated Alkynes ◽  
Acidic Conditions ◽  
High Stereoselectivity

<p>A stereoselective aminoiodination of activated alkynes with PhI(OAc)<sub>2</sub> and amines <i>via</i> multiple-site functionalization to afford (<i>Z</i>)diethyl 2-(diphenylamino)-3-iodomaleate derivatives with superior yields has been described. The key feature of this reaction is the incorporation of iodide and aryl group concurrently in the same molecule in a stereoselective manner by employing PhI(OAc)<sub>2</sub> as electrophilic reagent as well as iodide and aryl group source. The high stereoselectivity of the reaction can be explained based on the structure of the possible intermediates, the conformations of which controlled by the hydrogen bonding, steric hindrance and electrostatic attractions. This reaction proceeds under mild conditions, providing various dialkyl 2-(diphenylamino)-3-iodomaleates by a single operation starting from activated alkynes. The robustness of our strategy is revealed by making of bis (dialkyl 2-(diphenylamino)-3-iodomaleate) derivatives involving formation of four new C-N bonds and two C-I bonds with a single step. The synthesized inactive 3° enamines (dialkyl 2-(diphenylamino)-3-iodomaleates) could be further transformed into highly substituted indoles via Pd catalyzed C-H and C-I activation under non-acidic conditions. </p><br>

Effect of steric hindrance on hydrogen-bonding interaction between polyesters and natural polyphenol catechin

2004 ◽  
Vol 91 (6) ◽  
pp. 3565-3573 ◽  
Author(s):  
Bo Zhu ◽  
Jianchun Li ◽  
Yong He ◽  
Hideki Yamane ◽  
Yoshiharu Kimura ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Steric Hindrance ◽  
Hydrogen Bonding Interaction ◽  
Bonding Interaction ◽  
Natural Polyphenol

scholarly journals Competition Between Steric Hindrance and Hydrogen Bonding in the Formation of Supramolecular Bottle Brush Polymers

2013 ◽  
Vol 46 (19) ◽  
pp. 7911-7919 ◽  
Author(s):  
Sylvain Catrouillet ◽  
Cécile Fonteneau ◽  
Laurent Bouteiller ◽  
Nicolas Delorme ◽  
Erwan Nicol ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Steric Hindrance ◽  
Bottle Brush ◽  
Brush Polymers
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