Carbon-donated hydrogen bonding: Electrostatics, frequency shifts, directionality, and bifurcation

2008 ◽  
Vol 108 (15) ◽  
pp. 2914-2923 ◽  
Author(s):  
Katherine Compaan ◽  
Robert Vergenz ◽  
Paul Von Rague Schleyer ◽  
Isis Arreguin
Keyword(s):  
Hydrogen Bonding ◽  
Frequency Shifts

Infrared frequency shifts of phenol due to hydrogen bonding with substituted aromatics

1967 ◽  
Vol 32 (9) ◽  
pp. 2803-2806 ◽  
Author(s):  
Eiji Osawa ◽  
Tokinobu Kato ◽  
Zenichi Yoshida
Keyword(s):  
Hydrogen Bonding ◽  
Frequency Shifts

An Infra-Red Study of the Association of Diazoaminobenzene

1960 ◽  
Vol 13 (2) ◽  
pp. 230
Author(s):  
LK Dyall
Keyword(s):  
Hydrogen Bonding ◽  
Equilibrium Constant ◽  
Linear Relation ◽  
Intramolecular Hydrogen Bonding ◽  
Dimer Formation ◽  
Frequency Shifts ◽  
Infra Red ◽  
Intramolecular Hydrogen

The infra-red spectrum of diazoaminobenzene reveals that dimeric association occurs through hydrogen bonding. In tetrachloroethylene solution, the equilibrium constant for dimer formation is found to be 1.2�0.2 1 mol-1. The effects of various solvents on the free N-H stretching frequency have been examined, and the frequency shifts are linearly related to those reported by Bellamy and Hallam (1959) for pyrrole. A linear relation of this type is also found for %nitroaniline, and confirms that there is no significant intramolecular hydrogen bonding in this compound.

Vibrational Frequency Shifts of the Carbonyl Stretching Mode Induced by Solvents: Acetone

1989 ◽  
Vol 43 (6) ◽  
pp. 1053-1055 ◽  
Author(s):  
R. A. Nyquist ◽  
T. M. Kirchner ◽  
H. A. Fouchea
Keyword(s):  
Hydrogen Bonding ◽  
Vibrational Frequency ◽  
Molecular Geometry ◽  
Intermolecular Hydrogen Bonding ◽  
Acceptor Number ◽  
Frequency Shifts ◽  
Solvent Interaction ◽  
Precise Measure ◽  
Solvent Systems ◽  
Solute Solvent Interaction

Variation in the correlations obtained between electron acceptor number (AN) values for each solvent versus the vC=O frequencies for acetone and tetramethylurea in solution with these solvents suggests that the AN values are not a precise measure of solute/solvent interaction for all solute/solvent systems. Factors such as intermolecular hydrogen bonding between solute and solvent and the differences between molecular geometry of the solutes and solvents most likely account for differences in the solute/solvent interaction for different solutes in the same solvents.

A SPECTROSCOPIC STUDY OF HYDROGEN BONDING IN PERFORMIC AND PERACETIC ACIDS

1952 ◽  
Vol 30 (11) ◽  
pp. 821-830 ◽  
Author(s):  
Paul A. Giguère ◽  
A. Weingartshofer Olmos
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Spectroscopic Study ◽  
Infrared Spectra ◽  
Peracetic Acid ◽  
The Other ◽  
Frequency Shifts ◽  
Vapor State ◽  
Nonpolar Solvents ◽  
Intramolecular Hydrogen

The infrared spectra of concentrated performic and peracetic acids were measured in the rock-salt region. The most significant features are theO—H stretching frequency at 3310–3350 cm−1 and the OH bending frequency at 1450 cm−1 which, for both peracids, remain essentially the same in the vapor state as in the liquid or in solution in nonpolar solvents. This is attributed to intramolecular hydrogen bonds resulting in particularly stable five-membered rings,[Formula: see text]Steric conditions in the percarboxylic group are favourable to such ring formation or chelation. From the observed frequency shifts the energy of these hydrogen bonds is estimated to be about 7 kcal. per mole. No evidence for unchelated molecules was found even in very dilute solutions of peracetic acid in nonpolar solvent nor in the vapour at low pressure and moderate temperature. Tentative assignments of the other frequencies in the spectra of the peracids are made by comparison with those of formic and acetic acids.The danger involved in handling these peracids in concentrated form is emphasized.

scholarly journals THEORETICAL VS. EXPERIMENTAL IR FREQUENCY SHIFTS UPON Π- HYDROGEN BONDING: COMPLEXES OF SUBSTITUTED PHENOLS WITH HEXAMETHYLBENZENE

2017 ◽  
Vol 38 (1) ◽  
pp. 33
Author(s):  
Valia Nikolova ◽  
Boris Galabov
Keyword(s):  
Hydrogen Bonding ◽  
Density Functional ◽  
Theoretical Method ◽  
Substituted Phenols ◽  
Experimental Ir ◽  
Functional Theory ◽  
Frequency Shifts ◽  
Hydrogen Bond Formation ◽  
Experimental Parameters

The quality of theoretical prediction of O-H stretching frequency shifts upon π-hydrogen bonding is analyzed for series of ten complexes between monosubstituted phenols and hexamethylbenzene. Computed O-H frequencies from density functional theory computations at B3LYP/6-311++G(2df,2p) were compared with literature spectroscopic data. The results reveal that the applied theoretical method predicts with an excellent accuracy the O-H frequency shifts [Δυ(OH)] upon π-hydrogen bond formation. Comparisons with analogous theoretical and experimental data for benzene complexes with substituted phenols reveal the magnitude of the methyl groups’ hyperconjugative effects on interaction energies and frequency shifts. The induced by phenol substituents variations in bonding energies and Δυ(OH) are ra-tionalized using theoretically evaluated and experimental parameters.

Hydrogen bonding between phenols and cyanides

1966 ◽  
Vol 291 (1427) ◽  
pp. 460-468 ◽  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Carbon Tetrachloride ◽  
Equilibrium Constants ◽  
Lone Pair ◽  
Frequency Shifts ◽  
Tertiary Butyl ◽  
Group Frequency ◽  
Steric Factors ◽  
Lone Pair Electrons

The association between phenols and cyanides, dissolved in carbon tetrachloride, has been measured. The shifts of the bonded OH group frequency have been determined for a range of cyanides, and correlated with the Taft inductive factors of the groups concerned. Equilibrium constants for the formation of the complexes have been determined and correlated with the frequency shifts. The influence of steric factors has been studied, and it has been found that tertiary butyl groups in the ortho positions of phenol restrict the formation of the hydrogen bond. In most cases, the C≡N group frequency is displaced to higher frequency when bonded to a phenol. This effect is unusual, and suggests that the bonding occurs through the lone pair electrons on the nitrogen atom. Some data on the widths of the association bands have been given.

The dependence of thymine and thymidine Raman spectra on solvent

2004 ◽  
Vol 82 (6) ◽  
pp. 1092-1101 ◽  
Author(s):  
L Beyere ◽  
P Arboleda ◽  
V Monga ◽  
G R Loppnow
Keyword(s):  
Raman Spectroscopy ◽  
Hydrogen Bonding ◽  
Raman Spectra ◽  
Vibrational Modes ◽  
Frequency Shifts ◽  
Hydrogen Bonding Interactions ◽  
Lone Pairs ◽  
Vibrational Bands ◽  
Donor Numbers ◽  
Solvent Molecules

Recent work has focused on developing Raman spectroscopy as a noninvasive probe of DNA interactions with solvents, intercalants, proteins, and other ligands. Here, we report the Raman spectra of thymine in eight solvents and thymidine in nine solvents obtained with visible excitation. Raman spectra under acidic, neutral, and basic conditions were also obtained of both thymine and thymidine. Changes in both the frequencies and intensities of several of the vibrational bands in the 800–1800 cm–1 region are observed. No evidence of deprotonation in the different solvents is observed for either thymine or thymidine. Correlations of the observed frequency shifts of specific vibrational modes with characteristic properties of the solvent for both thymine and thymidine show a significant correlation with acceptor and donor numbers, measures of the hydrogen-bonding ability of the solvent, in both thymine and thymidine. These results are interpreted in terms of hydrogen-bonding interactions between the N-H protons of the thymine base and lone pairs of electrons on the solvent molecules and between the solvent hydrogens and lone pairs on C=O sites. The solvent-dependent intensity in vibrational bands of thymine between 1500 and 1800 cm–1 indicates a strong interaction between thymine and solvent at the C=O and N-H sites that leads to separation of the C=O stretches from the C=C stretch. The intensity variations with solvent were much smaller for thymidine than for thymine, perhaps as a result of replacing the N1 proton by the sugar. These results suggest that Raman spectroscopy is uniquely sensitive to specific interactions of thymine and thymidine with their environment.Key words: Raman spectroscopy, thymine, thymidine, solvent effects, hydrogen bonding.

Sign in / Sign up

Export Citation Format

Share Document