scholarly journals Biomimetic hydrogen-bonding cascade for chemical activation: telling a nucleophile from a base

2021 ◽  
Author(s):  
Hyunchang Park ◽  
Dongwhan Lee
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Reaction Pathway ◽  
Chemical Activation ◽  
Reaction Site ◽  
Acid Base ◽  
Electrophilic Reaction

Biomimetic cascade hydrogen bonds promote covalent capture of a nucleophile by polarizing the electrophilic reaction site, while suppressing non-productive acid–base chemistry as the competing reaction pathway.

scholarly journals Hydrogen Bonds: Raman Spectroscopic Study

2021 ◽  
Vol 22 (10) ◽  
pp. 5380
Author(s):  
Boris A. Kolesov
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Spectroscopic Study ◽  
Raman Spectra ◽  
Temperature Region ◽  
Vibrational Frequency ◽  
Chemical Compounds ◽  
Raman Spectroscopic ◽  
Raman Spectroscopic Study ◽  
Proton Dynamics

The work outlines general ideas on how the frequency and the intensity of proton vibrations of X–H×××Y hydrogen bonding are formed as the bond evolves from weak to maximally strong bonding. For this purpose, the Raman spectra of different chemical compounds with moderate, strong, and extremely strong hydrogen bonds were obtained in the temperature region of 5 K–300 K. The dependence of the proton vibrational frequency is schematically presented as a function of the rigidity of O-H×××O bonding. The problems of proton dynamics on tautomeric O–H···O bonds are considered. A brief description of the N–H···O and C–H···Y hydrogen bonds is given.

scholarly journals Self-Assembled Bimetallic Aluminum-Salen Catalyst for the Cyclic Carbonates Synthesis

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4097
Author(s):  
Wooyong Seong ◽  
Hyungwoo Hahm ◽  
Seyong Kim ◽  
Jongwoo Park ◽  
Khalil A. Abboud ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Self Assembly ◽  
Reaction Pathway ◽  
Kinetic Studies ◽  
Cyclic Carbonate ◽  
Reaction Conditions ◽  
Formation Reaction ◽  
X Ray ◽  
Carbonate Formation ◽  
Salen Aluminum

Bimetallic bis-urea functionalized salen-aluminum catalysts have been developed for cyclic carbonate synthesis from epoxides and CO2. The urea moiety provides a bimetallic scaffold through hydrogen bonding, which expedites the cyclic carbonate formation reaction under mild reaction conditions. The turnover frequency (TOF) of the bis-urea salen Al catalyst is three times higher than that of a μ-oxo-bridged catalyst, and 13 times higher than that of a monomeric salen aluminum catalyst. The bimetallic reaction pathway is suggested based on urea additive studies and kinetic studies. Additionally, the X-ray crystal structure of a bis-urea salen Ni complex supports the self-assembly of the bis-urea salen metal complex through hydrogen bonding.

Ethanol conversion over Ga2O3-ZrO2 solid solution: empirical evidences of the reaction pathway, the surface acid–base property, and role of isolated gallium ion

2021 ◽  
Author(s):  
Takashi Yamamoto ◽  
Akihito Kurimoto ◽  
Riona Sato ◽  
Shoki Katada ◽  
Hirotaka Mine ◽  
...  
Keyword(s):  
Solid Solution ◽  
Reaction Pathway ◽  
Ethanol Conversion ◽  
Acid Base ◽  
Base Property ◽  
Temperature Range ◽  
Acid Base Property

Ethanol conversion by Ga2O3-ZrO2 solid solution was examined in the temperature range 573–773 K, and acetone/isobutene formation was confirmed under cofeeding of H2O vapor. The reaction pathway was empirically investigated...

scholarly journals Hydrogen bonding to the cysteine ligand of superoxide reductase: acid–base control of the reaction intermediates

2013 ◽  
Vol 18 (7) ◽  
pp. 815-830 ◽  
Author(s):  
Emilie Tremey ◽  
Florence Bonnot ◽  
Yohann Moreau ◽  
Catherine Berthomieu ◽  
Alain Desbois ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Superoxide Reductase ◽  
Reaction Intermediates ◽  
Acid Base

2-Hydroxy-3-methoxybenzaldehyde (pyridinium-4-ylcarbonyl)hydrazone chloride hemihydrate

2006 ◽  
Vol 62 (5) ◽  
pp. o2043-o2044 ◽  
Author(s):  
Shao-Wen Chen ◽  
Han-Dong Yin ◽  
Da-Qi Wang ◽  
Xia Kong ◽  
Xiao-Fang Chen
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Compound C

The crystal structure of the title compound, C14H14ClN3O3 +·Cl−·0.5H2O, exhibits O—H...O, C—H...O, C—H...Cl, N—H...Cl and O—H...Cl hydrogen bonds. The chloride anions participate in extensive hydrogen bonding with the aminium cations and link molecules through multiple N—H+...Cl− interactions.

ChemInform Abstract: Receptors for Oxo Acids: Effects of Intra-Ion-Pair Hydrogen Bonding on Acid-Base Equilibria.

ChemInform ◽  
2010 ◽  
Vol 25 (12) ◽  
pp. no-no
Author(s):  
K. MANABE ◽  
K. OKAMURA ◽  
T. DATE ◽  
K. KOGA
Keyword(s):  
Hydrogen Bonding ◽  
Ion Pair ◽  
Acid Base

Five pseudopolymorphs of 6-amino-2-thiouracil: absence of N—H...S hydrogen bonds

2012 ◽  
Vol 69 (1) ◽  
pp. 93-100 ◽  
Author(s):  
Wilhelm Maximilian Hützler ◽  
Michael Bolte
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Cambridge Structural Database ◽  
Hydrogen Bonding Pattern ◽  
Crystallization Experiments ◽  
Structural Database ◽  
Thiouracil Derivatives

In order to study the preferred hydrogen-bonding pattern of 6-amino-2-thiouracil, C4H5N3OS, (I), crystallization experiments yielded five different pseudopolymorphs of (I), namely the dimethylformamide disolvate, C4H5N3OS·2C3H7NO, (Ia), the dimethylacetamide monosolvate, C4H5N3OS·C4H9NO, (Ib), the dimethylacetamide sesquisolvate, C4H5N3OS·1.5C4H9NO, (Ic), and two different 1-methylpyrrolidin-2-one sesquisolvates, C4H5N3OS·1.5C5H9NO, (Id) and (Ie). All structures containR21(6) N—H...O hydrogen-bond motifs. In the latter four structures, additionalR22(8) N—H...O hydrogen-bond motifs are present stabilizing homodimers of (I). No type of hydrogen bond other than N—H...O is observed. According to a search of the Cambridge Structural Database, most 2-thiouracil derivatives form homodimers stabilized by anR22(8) hydrogen-bonding pattern, with (i) only N—H...O, (ii) only N—H...S or (iii) alternating pairs of N—H...O and N—H...S hydrogen bonds.

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