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Hydrogen bond acidity
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Ebook "Development of novel hydrogen-bond donor catalysts" describes novel, effective hydrogen-bond (HB) donor catalysts based on a known bifunctional tertiary amine-thiourea, a privileged structure, which has been proven to be one of the most widely used organocatalysts. These HB donor catalysts derived from quinazoline and benzothiadiazine were initially synthesized as novel HB donors with their HB-donating abilities being measured by analytical methods.
119p
coduathanh1122
27-03-2024
1
1
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Biorefinery with deep eutectic solvent (DES) is an emerging processing technology to overcome the shortcomings of conventional biomass pretreatments. This work evaluates the biorefinery of sugarcane bagasse (SCB) with DES formulated with choline chloride as hydrogen bond acceptor and three hydrogen bond donors: lactic acid, citric acid, and acetic acid.
8p
vihermione
30-12-2022
9
2
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In this work, we present the acidity of BAS and silanols in zeolites depending on their configurations in zeolite nanoparticles. The acidity was evaluated based on the deprotonation energy (DPE) calculated by the density functional method and compared to experimental spectra.
8p
vironald
15-12-2022
9
2
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The paper presents a new kind of stationary phase for gas chromatography based on deep eutectic solvents (DES) in the form of a mixture of L-proline (protonated with hydrochloric acid) as a hydrogen bond acceptor (HBA) and xylitol as a hydrogen bond donor (HBD) in a molar ratio of HBA:HBD 5:1.
8p
vironald
15-12-2022
4
2
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The intermolecular interactions between halocyclopropenone derivatives (HC3OX; X = I, Br, Cl, and F) and hypohalous acids (HOY; Y = I, Br, Cl, and F) were studied via the MP2 method utilizing the aug-cc-pVTZ and aug-cc-pVTZ(-PP) basis sets. The three types of complexes were hydrogen bonds, halogen bonds, and complexes containing both hydrogen and halogen bonds. The results obtained indicated that interactions in the Type 1 complexes were stronger than those in Types 2 and 3. The H–O bonds revealed red shifts with complex formation in Types 1 and 2.
14p
tudichquannguyet
29-11-2021
12
1
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Phthalocyanines (Pcs) are established sensitive materials for chemical gas sensors due to their superb sensing characteristics and the achievable manifold in their analyte interaction properties. Their sorption properties are determined by the metal ion center and substituents attached to the periphery of the ring system. Similarly, vic-dioximes can be modified in their sorption properties and employed as sensitive materials.
12p
tudichquannguyet
29-11-2021
8
2
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We report the synthesis and liquid crystalline properties of a new type of tribranched compound built up from triazine as the central core and electron-rich triazine rings as peripheral groups. An equimolar mixture of the star-shaped compound based on the 1,3,5-triazine core with 4-dodecyloxybenzoic acid produced an organic salt exhibiting a columnar mesophase with a dendritic growing texture at low temperatures. The liquid crystalline properties of the triazine-based compound and organic salt were investigated by differential scanning calorimetry and polarizing optical microscopy.
9p
tudichquannguyet
29-11-2021
3
1
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In this study, we reported the synthesis of a new tribranched macromolecule liquid crystal with triazine in the centre. The central triazine core is bonded via sequences of Sonigashira coupling to 3 triazine unites through acetylenic bridges. The triazines at the periphery are substituted with 2 chiral citronellyloxy side groups. The salt of the resulting star-shaped macromolecule, which was oily at room temperature, with 4-dodecyloxybenzoic acid at 1:1 ratio exhibited a Smectic C (SmC) mesophase.
21p
tudichquannguyet
29-11-2021
5
1
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Lecture Principles of Biology - Chapter 3: What’s so great about water? After completing this section, you will understand the knowledge about polar nature of water molecules, what properties of water are important for life, acids and bases, some useful definitions,...
57p
bachtudu
30-09-2021
14
1
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This chapter presents the following content: Polar covalent bonds in water molecules result in hydrogen bonding, four emergent properties of water contribute to Earth's suitability for life, acidic and basic conditions affect living organisms.
39p
tradaviahe14
27-01-2021
19
2
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This chapter presents the following content: structure of the double bond, the sigma bond, the pi bond, orbital energies, how weak is the pi bond? Bond strengths in alkenes, alkenyl hydrogens are relatively acidic, degree of unsaturation, heteroatoms and degree of unsaturation,...
29p
larachdumlanat122
26-11-2020
11
2
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Pentyl 2-(1H-indole-2-carboxamido)benzoate (5) is obtained in good yield as stable crystals by reaction of pentyl 2-amino benzoate (6) with indole-2-carbonyl chloride acid (7) in the presence of pyridine. The crystal structure of 5 confirms the presence of intramolecular hydrogen bonding (N-H…O) which produces a six-membered ring, and the molecules are linked together by intermolecular hydrogen forces (N-H…O).
6p
tocectocec
25-05-2020
7
0
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Design of multivalent ligand is significant in restraining the interaction involved in the binding of influenza virus to its host cell. This molecular dynamics (MD) simulation study aims to study the mode of binding of dimeric NeuNAc analogues coupled by different nano-spacers into the multimeric binding sites of neuraminidase and haemagglutinin of influenza A H5N1 virus. In total, 80 NeuNAc analogue dimers were modeled and docked against the binding sites of neuraminidase and haemagglutinin.
30p
nguaconbaynhay1
04-12-2019
12
2
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Trichloroisocyanuric acid synthesis process was studied by using DFT method. The obtained results demonstrate that the keto-enol isomerization of the cyanuric acid is a base-catalyzed reaction. It is possible that in the presence of NaOH the process of moving hydrogen in the cyanuric acid molecule and the reaction of neutralizing cyanuric acid can execute consecutively. And in this case NaOH plays the role as a donor of hydroxyl group catalyzing the movement of hydrogen and as neutralizing agent in an exothermal process.
6p
uocvong04
24-09-2015
57
2
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The complexes of acidic quinine solution with acidic solutions of sulfate-salts of Fe, Zn and Ce have been synthesized. Bonds of Fe-O, Zn-O and Ce-O were formed via the hydroxyl oxygen atom with a preservation of hydrogen bond and have been proved by the infrared spectroscopy.
5p
uocvong04
24-09-2015
50
4
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The different roles of ubiquinone-10 (UQ10) at the primary and secondary quinone (QAand QB) binding sites ofRho-dobacter sphaeroidesR26 reaction centres are governed by the protein microenvironment. The 4C¼O carbonyl group of QAis unusually strongly hydrogen-bonded, in contrast to QB. This asymmetric binding seems to determine their dif-ferent functions. The asymmetric hydrogen-bonding at QA can be caused intrinsically by distortion of the methoxy groups or extrinsically by binding to specific amino-acid side groups. ...
7p
tumor12
20-04-2013
31
1
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Cn12 isolated from the venom of the scorpionCentruroides noxiushas 67 amino-acid residues, closely packed with four disulfide bridges.Its primary structure and disulfide bridges were determined.Cn12 is not lethal to mammals and arthropodsin vivoat doses up to 100lgper animal.Its3D structure was determined by proton NMR using 850 dis-tance constraints, 36 /angles derived from 36 coupling constants obtained by two different methods, and 22 hydrogen bonds.
13p
dell39
03-04-2013
45
2
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NA helicases are ubiquitous molecular motor proteins which harness the chemical free energy of ATPhydrolysis to catalyze the unwinding of energetically stable duplex DNA, and thus play important roles in nearly all aspects of nucleic acid metabolism, including replication, repair, recombina-tion, and transcription. They break the hydrogen bonds between the duplex helix and move unidirectionally along the bound strand. All helicases are also translocases and DNA-dependentATPases.Most contain conserved helicase motifs that act as an engine to power DNA unwinding. ...
14p
dell39
03-04-2013
35
4
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Alternate DNA structures that deviate from B-form double-stranded DNA such as G-quadruplex (G4) DNA can be formed by sequences that are widely distributed throughout the human genome. G-quadruplex secondary structures, formed by the stacking of planar quartets composed of four guanines that interact by Hoogsteen hydrogen bonding, can affect cellular DNA replication and transcription, and influence genomic stability.
19p
viettel02
19-02-2013
28
2
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Tham khảo sách 'harper’s illustrated biochemistry twenty-eighth edition_1', y tế - sức khoẻ, y học thường thức phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả
469p
hyperion75
18-01-2013
50
7
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