Enthalpies of interaction of nitrogen base solutes with organic solvents

1985 ◽  
Vol 63 (9) ◽  
pp. 2540-2544 ◽  
Author(s):  
W. Kirk Stephenson ◽  
Richard Fuchs
Keyword(s):  
Hydrogen Bond ◽  
Organic Solvents ◽  
Butyl Alcohol ◽  
Hydrogen Bond Donor ◽  
Butyl Ether ◽  
Hydrogen Bond Acceptor ◽  
Nitrogen Base ◽  
Benzene Toluene ◽  
Polar Interactions ◽  
S Model

Heats of solution of triethylamine, aniline, pyridine, and model compounds (3-ethylpentane, benzene) in 17 organic solvents (n-heptane, cyclohexane, carbon tetrachloride, 1,2-dichloroethane, α,α,α-trifluorotoluene, triethylamine, butyl ether, ethyl acetate, dimethylformamide, dimethyl sulfoxide, benzene, toluene, mesitylene, t-butyl alcohol, 1-octanol, methanol, 2,2,2-trifluoroethanol) have been combined with solute heats of vaporization to give enthalpies of transfer from vapor to solvent (ΔH(v → s)). Differences between solute and model values (ΔΔH(v → s) = ΔH(v → s) (solute) – ΔH(v → s) (model)) were used to evaluate nitrogen base solute–solvent polar interactions. Correlations of ΔΔH(v → s) with Taft–Kamlet solvatochromic parameters (π*, α, β) have been determined.Aniline was found to be a better hydrogen bond donor acid than hydrogen bond acceptor base. Nevertheless, alcohols donate H-bonds to aniline. Triethylamine and pyridine are stronger HBA bases than aniline. The π* (dipolarity–polarizability) parameter of aniline (as a solute) is calculated to be 1.10.

Enthalpies of interaction of aromatic solutes with organic solvents

1985 ◽  
Vol 63 (9) ◽  
pp. 2529-2534 ◽  
Author(s):  
W. Kirk Stephenson ◽  
Richard Fuchs
Keyword(s):  
Organic Solvents ◽  
Butyl Alcohol ◽  
Model Compounds ◽  
Butyl Ether ◽  
Enthalpies Of Transfer ◽  
Benzene Toluene ◽  
Polar Interactions ◽  
S Model ◽  
Heats Of Vaporization ◽  
Butyl Methyl Ether

Heats of solution of several aromatic solutes (benzene, toluene, mesitylene, nitrobenzene, α,α,α-trifluorotoluene, anisole) and model compounds (n-butyl methyl ether, cyclohexane) in 17 organic solvents (n-heptane, cyclohexane, carbon tetrachloride, 1,2-dichloroethane, α,α,α-trifluorotoluene, triethylamine, butyl ether, ethyl acetate, dimethylformamide, dimethyl sulfoxide, benzene, toluene, mesitylene, t-butyl alcohol, 1-octanol, methanol, 2,2,2-trifluoroethanol) have been combined with solute heats of vaporization to give enthalpies of transfer from vapor to solvent (ΔH(v → S)). Differences between solute and model values (ΔΔH(v → S) = ΔH(v → S) (aromatic solute)–ΔH(v → S) (model) were used to evaluate aromatic solute–solvent polar interactions. Correlations of ΔΔH(v → S) with solvent dipolarity–polarizability (Taft–Kamlet π* parameter) have been determined.

Enthalpies of interaction of ketones with organic solvents

1985 ◽  
Vol 63 (2) ◽  
pp. 336-341 ◽  
Author(s):  
W. Kirk Stephenson ◽  
Richard Fuchs
Keyword(s):  
Organic Solvents ◽  
Bond Formation ◽  
Butyl Alcohol ◽  
Enthalpies Of Solution ◽  
Butyl Ether ◽  
Hydrogen Bond Formation ◽  
Linear Relationships ◽  
Benzene Toluene ◽  
Polar Interactions ◽  
Alcohol Solvents

Enthalpies of solution (ΔHS) of a series of ketones (acetone, 2-butanone, 2-heptanone, 2-nonanone, 5-nonanone, 2,2,4,4-tetramethyl-3-pentanone, cyclohexanone) and alkane model compounds (n-heptane, n-nonane, 2,2,4,4-tetramethylpentane, cyclohexane) have been determined in 17 organic solvents (n-heptane, cyclohexane, CCl4, α,α,α,-trifluorotoluene, 1,2-dichloroethane, triethylamine, butyl ether, ethyl acetate, DMF, DMSO, benzene, toluene, mesitylene, 1-octanol, methanol, t-butyl alcohol, 2,2,2-trifluoroethanol), and combined with heats of vaporization to give enthalpies of transfer from vapor to solvent (ΔH(v → S)). These values have been used to evaluate ketone–solvent polar interactions (ΔΔH(v → S) = ΔH(v → S)(ketone) − ΔH(v → S)(alkane)). The linear relationships between ΔΔH(v → S) and solvent dipolarity-polarizability (Taft-Kamlet π* parameters) are derived. Based on the deviations from these correlations, ketone–CF3CH2OH enthalpies of hydrogen bond formation have been evaluated. The other alcohol solvents show no evidence of exothermic H-bond formation with ketones.

Enthalpies of interaction of hydroxylic solutes with organic solvents

1985 ◽  
Vol 63 (9) ◽  
pp. 2535-2539 ◽  
Author(s):  
W. Kirk Stephenson ◽  
Richard Fuchs
Keyword(s):  
Organic Solvents ◽  
Methyl Ether ◽  
Butyl Alcohol ◽  
Amyl Alcohol ◽  
Solvatochromic Parameters ◽  
Model Compounds ◽  
Butyl Ether ◽  
Donor Solvent ◽  
Benzene Toluene ◽  
Butyl Methyl Ether

Heats of solution of m-cresol, 1-butanol, 1-pentanol, t-amyl alcohol, and model compounds (toluene, ethyl ether, n-butyl methyl ether, t-butyl methyl ether) in 17 organic solvents (n-heptane, cyclohexane, carbon tetrachloride, 1,2-dichloroethane, α,α,α-trifluorotoluene, triethylamine, butyl ether, ethyl acetate, dimethylformamide, dimethyl sulfoxide, benzene, toluene, mesitylene, t-butyl alcohol, 1-octanol, methanol, 2,2,2-trifluoroethanol) have been combined with solute heats of vaporization to give solvation enthalpies (ΔH(v → S)). Dependencies of solute vs. model solvation enthalpy differences on solvent dipolarity–polarizability and hydrogen-bond-accepting basicity were determined via correlations with Taft–Kamlet solvatochromic parameters (π*, β, ξ).m-Cresol is a substantially stronger H-bond donor than 1-butanol, 1-pentanol, and t-amyl alcohol, and H-bonds to acceptor solvents including alcohols. Cresol acts as an H-bond acceptor with the strong H-bond donor solvent trifluoroethanol.

6,9-Dibromo-2a,10b-diphenyl-2a,5,10,10b-tetrahydro-2H,3H-2,3,4a,10a-tetraazabenzo[g]cyclopenta[cd]azulene-1,4-dione monohydrate

2006 ◽  
Vol 62 (5) ◽  
pp. o1754-o1755
Author(s):  
Neng-Fang She ◽  
Sheng-Li Hu ◽  
Hui-Zhen Guo ◽  
An-Xin Wu
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Water Molecule ◽  
Title Compound ◽  
Supramolecular Structure ◽  
Hydrogen Bond Donor ◽  
Hydrogen Bond Acceptor ◽  
Compound C ◽  
Bifurcated Hydrogen Bond

The title compound, C24H18Br2N4O2·H2O, forms a supramolecular structure via N—H...O, O—H...O and C—H...O hydrogen bonds. In the crystal structure, the water molecule serves as a bifurcated hydrogen-bond acceptor and as a hydrogen-bond donor.

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.

scholarly journals The Characteristics of PD-L1 Inhibitors, from Peptides to Small Molecules

Molecules ◽  
2019 ◽  
Vol 24 (10) ◽  
pp. 1940 ◽  
Author(s):  
Yanwen Zhong ◽  
Xuanyi Li ◽  
Hequan Yao ◽  
Kejiang Lin
Keyword(s):  
Hydrogen Bond ◽  
Small Molecules ◽  
Pharmacophore Model ◽  
Amino Acid Residues ◽  
Tumor Treatment ◽  
Hydrogen Bond Donor ◽  
Treatment Results ◽  
Hydrogen Bond Acceptor ◽  
Checkpoint Pathway ◽  
Pharmacophore Models

The programmed cell death ligand protein 1 (PD-L1) is a member of the B7 protein family and consists of 290 amino acid residues. The blockade of the PD-1/PD-L1 immune checkpoint pathway is effective in tumor treatment. Results: Two pharmacophore models were generated based on peptides and small molecules. Hypo 1A consists of one hydrogen bond donor, one hydrogen bond acceptor, two hydrophobic points and one aromatic ring point. Hypo 1B consists of one hydrogen bond donor, three hydrophobic points and one positive ionizable point. Conclusions: The pharmacophore model consisting of a hydrogen bond donor, hydrophobic points and a positive ionizable point may be helpful for designing small-molecule inhibitors targeting PD-L1.

Infrared spectroscopic characterization of hydrogen-bonded propylene oxide − ethanol and propylene oxide − 2-fluoroethanol complexes isolated in solid neon matrices

2013 ◽  
Vol 91 (12) ◽  
pp. 1292-1302 ◽  
Author(s):  
Osama Y. Ali ◽  
Elyse Jewer ◽  
Travis D. Fridgen
Keyword(s):  
Hydrogen Bond ◽  
Propylene Oxide ◽  
Spectroscopic Characterization ◽  
Hydrogen Bond Donor ◽  
Hydrogen Bond Acceptor ◽  
Reduced Frequency ◽  
Enthalpy Of Proton Transfer ◽  
The Difference ◽  
Bonded Complexes ◽  
Hydrogen Bonded

The infrared absorption spectra of hydrogen-bonded complexes of propylene oxide with either ethanol or 2-fluoroethanol have been recorded in neon matrices. Mixtures of propylene oxide and ethanol or propylene oxide and 2-fluoroethanol vapors were mixed with an excess of neon gas and deposited onto a KBr substrate at 4.2 K. The results indicate that hydrogen-bonded complexes were formed with propylene oxide as the hydrogen bond acceptor and either ethanol or 2-fluoroethanol as the hydrogen bond donors. The features assigned to the O−H stretch were red-shifted by 175 and 193 cm−1 for the ethanol- and 2-fluoroethanol-containing complexes, respectively. The difference in red shifts can be accounted for due to the greater acidity of 2-fluroethanol. Deuterium isotope experiments were conducted to help confirm the assignment of the O–H stretch for the complexes. As well, structures and infrared spectra were calculated using B3LYP/6-311++G(2d,2p) calculations and were used to compare with the experimental spectra. A “scaling equation” rather than a scaling factor was used and is shown to greatly increase the utility of the calculations when comparing with experimental spectra. An examination of the O–H stretching red shifts for many hydrogen-bound complexes reveals a relationship between the shift and the difference between the acidity of the hydrogen bond donor and the basicity of the hydrogen bond acceptor (the enthalpy of proton transfer). Both hydrogen-bonded complexes and proton-bound complexes appear to have a maximum in the reduced frequency value that corresponds to complexes where the hydrogen/proton are equally shared between the two bases.

SINGLE MOLECULE IMMOBILIZATION OF π-CONJUGATED MOLECULES ON Au USING DENDRIMER-BASED TEMPLATES

2005 ◽  
Vol 04 (04) ◽  
pp. 467-473 ◽  
Author(s):  
ABDELHAK BELAISSAOUI ◽  
HIDEO TOKUHISA ◽  
EMIKO KOYAMA ◽  
MASATOSHI KANESATO
Keyword(s):  
Hydrogen Bond ◽  
Ftir Spectroscopy ◽  
Single Molecule ◽  
Binding Constant ◽  
Hydrogen Bond Donor ◽  
Hydrogen Bond Interaction ◽  
Hydrogen Bond Acceptor ◽  
Conjugated Molecules ◽  
The Core ◽  
Conjugated Molecule

We demonstrate that immobilization of a π-conjugated molecule containing a bipyridine moiety as a hydrogen bond acceptor on Au using a dendrimer-based template with 3,4-dihydroxybenzene moiety at the core as a hydrogen bond donor. The hydrogen bond interaction was used for the linkage between the conjugated molecule and the template to improve the method to fabricate single-molecule arrays we reported before.1 Although the binding constant is small ( K = 120 ± 20 M -1) in CDCl 3, it was demonstrated that the dendrimer spacer serves as a template to isolate the π-conjugated molecule, and is removable simply with a CH 2 Cl 2 rinsing by surface FTIR spectroscopy.

scholarly journals Review on Carbon Dioxide Absorption by Choline Chloride/Urea Deep Eutectic Solvents

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Rima J. Isaifan ◽  
Abdukarem Amhamed
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Bond ◽  
Ionic Liquids ◽  
Choline Chloride ◽  
Deep Eutectic Solvents ◽  
Absorption Capacity ◽  
Carbon Dioxide Absorption ◽  
Hydrogen Bond Donor ◽  
Separation Processes ◽  
Hydrogen Bond Acceptor

In the recent past few years, deep eutectic solvents (DESs) were developed sharing similar characteristics to ionic liquids but with more advantageous features related to preparation cost, environmental impact, and efficiency for gas separation processes. Amongst many combinations of DES solvents that have been prepared, reline (choline chloride as the hydrogen bond acceptor mixed with urea as the hydrogen bond donor) was the first DES synthesized and is still the one with the lowest melting point. Choline chloride/urea DES has proven to be a promising solvent as an efficient medium for carbon dioxide capture when compared with amine alone or ionic liquids under the same conditions. This review sheds light on the preparation method, physical and chemical characteristics, and the CO2 absorption capacity of choline chloride/urea DES under different temperatures and pressures reported up to date.

Sub-Pharmacophore Generation of JNK3 Inhibitors

2013 ◽  
Vol 444-445 ◽  
pp. 1756-1760 ◽  
Author(s):  
Yan Ling Zhang ◽  
Yuan Ming Wang ◽  
Yan Jiang Qiao
Keyword(s):  
Hydrogen Bond ◽  
Pharmacophore Model ◽  
High Specificity ◽  
Data Bank ◽  
Chinese Herbs ◽  
Mitogen Activated Protein Kinase ◽  
Specific Class ◽  
Hydrogen Bond Donor ◽  
Hydrogen Bond Acceptor ◽  
Appraisal Index

The structure-based pharmacophore (SBP) model is consisted by the complementarity of the chemical features and space of the interaction between the ligand and receptor. The SBP models always have a high specificity which can only represent the specific class of the ligand. To simplify the models, sub-pharmacophore was then proposed in present study, and was expected to have and only have the most important or the common chemical features which play the major role in the interaction of ligand and receptor. Sub-pharmacophore should contain 4-6 features, the higher specificity with more features, and vice versa. The sub-pharmacophore was generated by the random combination of features from the structure-based models. With the MDL Drug Data Report database used as the testing database, a new metric CAI (comprehensive appraisal index), which integrated the metrics of E and A%, was defined and used to determine the best sub-pharmacophore model. C-Jun N-terminal kinase (JNKs) is one of the mitogen-activated protein kinase family, and widely involved in immune response and inflammatory response, and other pathological processes. JNK3 is mainly distributed in the brain and nervous system. In present study, twenty-five initial SBP models of JNK3 inhibitors were directly constructed from the Protein Data Bank (PDB) complexes by the LigandScout software. Then, 1018 sub-pharmacophore models were obtained from the 25 initial models. Finally, the best sub-pharmacophore was determined which was simplified from the initial model generated from the 3FI2 complex, and included four features: one hydrogen bond donor, one hydrogen bond acceptor, and two hydrophobic groups. The metrics of E, A% and CAI value of the best sub-pharmacophore model are 17.47, 31.15 and 5.44, respectively. The potential JNK3 inhibitors were then identified from Chinese herbs with the best sub-pharmacophore model, and 286 compounds were obtained.

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