scholarly journals Adduct under Field—A Qualitative Approach to Account for Solvent Effect on Hydrogen Bonding

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 436 ◽  
Author(s):  
Ilya G. Shenderovich ◽  
Gleb S. Denisov
Keyword(s):  
Experimental Data ◽  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Solvent Effects ◽  
Qualitative Approach ◽  
Aprotic Solvents ◽  
Mobile Proton ◽  
Acid Base ◽  
Fluctuation Rate ◽  
Temperature Dependences

The location of a mobile proton in acid-base complexes in aprotic solvents can be predicted using a simplified Adduct under Field (AuF) approach, where solute–solvent effects on the geometry of hydrogen bond are simulated using a fictitious external electric field. The parameters of the field have been estimated using experimental data on acid-base complexes in CDF3/CDClF2. With some limitations, they can be applied to the chemically similar CHCl3 and CH2Cl2. The obtained data indicate that the solute–solvent effects are critically important regardless of the type of complexes. The temperature dependences of the strength and fluctuation rate of the field explain the behavior of experimentally measured parameters.

Study of Hydrogen Bonding in Carboxylic Acids by the MNDO/M Method

1994 ◽  
Vol 59 (6) ◽  
pp. 1251-1260 ◽  
Author(s):  
Michal Bureš ◽  
Jaroslav Bezus
Keyword(s):  
Experimental Data ◽  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Carboxylic Acids ◽  
Promising Method ◽  
Semiempirical Methods ◽  
Am1 Method ◽  
Bond Lengths ◽  
Pm3 Method

The semiempirical methods MNDO/M, AM1 and PM3 were applied to the study of hydrogen bonds in carboxylic acids. The calculated hydrogen bond lengths and enthalpies of dimerization were compared with experimental data. The AM1 method fails to properly describe systems with strong hydrogen bonds. The PM3 method predicts the hydrogen bond lengths correctly but underestimates systematically the enthalpies of dimerization. MNDO/M appears to be a promising method for the treatment of association of carboxylic acids.

Anharmonicity, solvent effects, and hydrogen bonding: NH stretching vibrations

1970 ◽  
Vol 48 (14) ◽  
pp. 2197-2203 ◽  
Author(s):  
A. Foldes ◽  
C. Sandorfy
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Solvent Effects ◽  
Bond Formation ◽  
Hydrogen Bond Formation ◽  
Stretching Vibration ◽  
Solvent Shifts ◽  
Stretching Vibrations ◽  
Secondary Amides ◽  
Influence Of Solvent

The influence of solvent effects and hydrogen bond formation on the anharmonicity of the NH stretching vibration of simple secondary amides, lactams, anilides, indole, pyrrole, and imidazole have been studied; and the frequencies of the first and second overtones, their half widths and solvent shifts measured. The validity of Buckingham's theory is established in the case of inert solvents; whereas the second order perturbation treatments are shown to be inapplicable to the case of hydrogen bonding solvents. All NH stretching modes seem to exhibit the same anharmonic behavior which is very different from that of OH vibrations.

scholarly journals Proton Transfer Equilibria and Critical Behavior of H-Bonding

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
L. Sobczyk ◽  
B. Czarnik-Matusewicz ◽  
M. Rospenk ◽  
M. Obrzud
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Proton Transfer ◽  
Dipole Moments ◽  
Electronic Polarizability ◽  
Bond Properties ◽  
Acid Base ◽  
Definition Of ◽  
Magnetic Resonances ◽  
Very High

The aim of the present paper is an analysis of the hydrogen bond properties for the acid-base systems depending on the ability to the proton transfer in the formulation of the Brönsted approach. After definition of the proton transfer equilibrium expressed by using the equation log KPT=ξΔpKN, various examples of different physical properties, such as dipole moments, IR spectra, and nuclear magnetic resonances, are presented which correlate with the ΔpKN value. In such a way, a critical state of hydrogen bonding can be defined that corresponds to the potential of the proton motion for either single minimum or double minimum with low barrier. A particular attention in this paper found electronic spectra which have not been analysed so far and the quantitative analysis of the vibrational polarizability which can reach very high values of the order of electronic polarizability.

Structures of three salts of phthalic acid; variation in crystal packing and geometry of the hydrogen phthalate ion

2004 ◽  
Vol 60 (5) ◽  
pp. 502-511 ◽  
Author(s):  
Annette Langkilde ◽  
Dennis Madsen ◽  
Sine Larsen
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Phthalic Acid ◽  
Crystal Packing ◽  
Molecular Geometry ◽  
Hydrogen Phthalate ◽  
Acid Base ◽  
Hydrogen Bond Pattern ◽  
Structural Database

The hydrogen-bond patterns in hydrogen phthalates (HP) have been elucidated by the determination of the crystal structures of hydrogen phthalate salts of [Mg(H2O)4-(CH3OH)2]2+, 2-(2′-pyridylamine)pyridinium and diethylammonium. The stoichiometry of the latter salt corresponds to a hydrogen phthalate salt; however, it contains the phthalic acid in its three possible acid–base forms. The hydrogen phthalate ions in the three salts display the two common hydrogen-bonding motifs. One has a very short intramolecular O—H—O hydrogen bond (Intra-H), as seen in the magnesium salt [O...O 2.397 (2) Å]. In the other two salts the hydrogen phthalate ions are connected by hydrogen bonds into infinite chains (Chain-H) with O...O distances of 2.460 (1) Å in the diethylamine salt and 2.610 (1) Å in the 2,2′-dipyridylamine salt. This difference in hydrogen-bond pattern was further elucidated by a search in the Cambridge Structural Database for other hydrogen phthalate salts. Intra-H possesses the shortest O...O distances and an almost planar hydrogen phthalate ion, whereas the hydrogen phthalate ions show significantly more variation in the Chain-H salts. The two hydrogen-bonding motifs are reflected in the molecular geometry of the hydrogen phthalate ion.

Insight into the deprotonation at the half-equivalence point of (thio)amido-benzimidazoles in the presence of anions

2017 ◽  
Vol 15 (35) ◽  
pp. 7263-7266 ◽  
Author(s):  
S. Koeller ◽  
M.-H. Lescure ◽  
C. Davies ◽  
J.-P. Desvergne ◽  
S. Massip ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bond Donor ◽  
Equivalence Point ◽  
Acid Base ◽  
Crystallographic Structures ◽  
Insight Into

Three crystallographic structures highlight the acid–base half-equivalence point of hydrogen-bond donor (thio)amido-benzimidazoles induced by fluoride or benzoate salts with concomitant hydrogen-bonding and deprotonation as a merged synergic process.

Proton N.M.R. of the muramyl dipeptide adjuvant in dimethyl sulfoxide

1982 ◽  
Vol 35 (3) ◽  
pp. 489 ◽  
Author(s):  
BE Chapman ◽  
M Batley ◽  
JW Redmond
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Chemical Shift ◽  
Dimethyl Sulfoxide ◽  
Chemical Shifts ◽  
Muramyl Dipeptide ◽  
Side Chain ◽  
Active Principle ◽  
Temperature Dependences ◽  
Amide Protons

The active principle of complete Freund's adjuvant, N-acetylmuramyl-L-alanyl-D-isoglutamine, was studied in the α-anomeric form in dimethyl sulfoxide solutions by 1H n.m.r, at 200 MHz. All resonances except those of the nonanomeric sugar protons were assigned. Temperature dependences of the chemical shifts of the amide protons indicated that the alanyl NH is involved in hydrogen bonding. The isoglutamine β-CH2 protons showed large chemical-shift nonequivalence, an effect consistent with a hydrogen bond to the side chain carboxyl of this residue.

Resonance and solvent effects on absorption spectra of 2-nitroaniline derivatives

1976 ◽  
Vol 29 (7) ◽  
pp. 1469 ◽  
Author(s):  
T Yokoyama
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Spectral Data ◽  
Absorption Spectra ◽  
Long Range ◽  
Solvent Effects ◽  
Intramolecular Hydrogen Bonding ◽  
Intramolecular Hydrogen

Spectral data for N-methyl-2-nitroaniline correlate well with those for N,N-dimethyl-2-nitroaniline in non-hydrogen-bonding, hydrogen-bond-accepting and amphiprotic alcoholic solvents. This same pattern has been reported for N-methyl-2-nitro-p-toluidine. These results indicate that these N-methyl compounds have no hydrogen bonds with any of the solvents studied and intramolecular hydrogen bonding predominates. In the N.M.R. spectra of such amines, long-range coupling between the H5 (ring) and N-H protons is not necessarily evidence for intramolecular hydrogen bonding.� +M substituents at the 4-position increase the twist of the dimethylamino and 2-nitro groups and enhance the C1 → C2 transition, an effect which follows the order of +M abilities of the 4-substituents.

Solid-State Photoreversible Polymerization of n-Alkyl-Linked Bis-Thymines using Non-Covalent Polymer-Templating

2010 ◽  
Vol 63 (4) ◽  
pp. 631 ◽  
Author(s):  
Priscilla Johnston ◽  
Milton T.W. Hearn ◽  
Kei Saito
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Solid State ◽  
Nucleic Acid ◽  
Green Chemistry ◽  
Vinyl Pyrrolidone ◽  
Acid Base ◽  
Polymer Templating ◽  
Nucleic Acid Base ◽  
Poly Vinyl Pyrrolidone

Procedures derived from bioinspired mechanisms are increasingly being used to create novel materials based on the principles of green chemistry. Thymine, a nucleic acid base in DNA, has the propensity to both hydrogen bond and photodimerize. Photodimerization of thymine occurs when irradiated at wavelengths of >270 nm and can be reversed by irradiation at wavelengths of <250 nm. In this investigation, n-alkyl-linked bis-thymines have been supramolecularly aligned with poly(vinyl pyrrolidone) templates by non-covalent hydrogen bonding, and photopolymerized in the solid state. Photo-depolymerization of the products was performed to complete the reversible polymerization.

Solvation and redox properties of [Co(en)3]3+-[Co(en)3]2+ system

1980 ◽  
Vol 45 (2) ◽  
pp. 335-338 ◽  
Author(s):  
Adéla Kotočová ◽  
Ulrich Mayer
Keyword(s):  
Hydrogen Bond ◽  
Lewis Acid ◽  
Specific Interaction ◽  
Redox Properties ◽  
Solvation Effect ◽  
Interacting Particles ◽  
Acid Base ◽  
Polar Solvents ◽  
Oxidation Reduction ◽  
Solvent Molecules

The solvation effect of a number of nonaqueous polar solvents was studied on the oxidation-reduction properties of the [Co(en)3]3+-[Co(en)3]2+ system. Interactions of these ions with the solvent molecules are discussed in terms of their coordination, which is accompanied by a specific interaction of the Lewis acid-base type, namely formation of a hydrogen bond between the interacting particles. This is the main controlling factor of the redox properties of the studied system.

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