scholarly journals Fermi resonance as a means to determine the hydrogen-bonding status of two infrared probes

2017 ◽  
Vol 19 (24) ◽  
pp. 16144-16150 ◽  
Author(s):  
Jeffrey M. Rodgers ◽  
Rachel M. Abaskharon ◽  
Bei Ding ◽  
Jianxin Chen ◽  
Wenkai Zhang ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Functional Group ◽  
Fermi Resonance ◽  
Coupling Constant ◽  
Resonance Coupling ◽  
Infrared Probes

This study shows that the Fermi resonance coupling constant (W) is indicative of the hydrogen-bonding status of a CO or CN functional group.

scholarly journals The Role of Fermi Resonance in Formation of Valence Band of Water Raman Scattering

2008 ◽  
Vol 2008 ◽  
pp. 1-4 ◽  
Author(s):  
Sergey A. Burikov ◽  
Tatiana A. Dolenko ◽  
Victor V. Fadeev
Keyword(s):  
Genetic Algorithms ◽  
Raman Scattering ◽  
Valence Band ◽  
Simultaneous Measurement ◽  
Fermi Resonance ◽  
Coupling Constant ◽  
Resonance Contribution ◽  
Resonance Coupling ◽  
Valence Bands

The role of Fermi resonance in formation of valence band of water Raman scattering was investigated. Simultaneous measurement of characteristics of bending and valence bands of water in solutions, KBr, and KCl and using genetic algorithms in conjunction with variation methods allowed increasing accuracy of estimation of Fermi resonance coupling constant and of Fermi resonance contribution into formation of water Raman valence band.

scholarly journals Conformational analysis and intramolecular interactions in monosubstituted phenylboranes and phenylboronic acids

2013 ◽  
Vol 9 ◽  
pp. 1127-1134 ◽  
Author(s):  
Josué M Silla ◽  
Rodrigo A Cormanich ◽  
Roberto Rittner ◽  
Matheus P Freitas
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Conformational Analysis ◽  
Conformational Equilibrium ◽  
Intramolecular Hydrogen Bonding ◽  
Intramolecular Interactions ◽  
Coupling Constant ◽  
Intramolecular Hydrogen ◽  
Phenylboronic Acids ◽  
Electron Donation

A 1 TS J F,H(O) coupling pathway, dictated by a hydrogen bond, in some 2-fluorobenzoic acids has been observed, while such an interaction does not occur in 2-fluorophenol. Thus, this work reports the conformational analysis of 2-fluorophenylboronic acid (1), in order to evaluate a possible intramolecular OH∙∙∙F hydrogen bond in comparison to an nF→pB interaction, which mimics the quantum nF→σ*OH hydrogen bond that would be expected in 2-fluorophenol. 2-Fluorophenylborane (3), which does not experience hydrogen bonding, was used to verify whether nF→pB interaction governs the conformational equilibrium in 1 due to a predominant OH∙∙∙F hydrogen bond or to other effects. A series of 2-X-phenylboranes (X = Cl, Br, NH2, PH2, OH and SH) were further computationally analyzed to search for electron donors to boron, capable of influencing the conformational equilibrium. Overall, the intramolecular OH∙∙∙F hydrogen bond in 1 is quite stabilizing and dictates the 1 h J F,H(O) coupling constant. Moreover, electron donation to the empty p orbital of boron (for noncoplanar BH2 moiety relative to the phenyl ring) is also significantly stabilizing for the NH2 and PH2 derivatives, but not enough to make the corresponding conformers appreciably populated, because of steric effects and the loss of πCC→pB resonance. Thus, the results found earlier for 2-fluorophenol about the lack of intramolecular hydrogen bonding are now corroborated.

Alkylammonium hexachlorostannates(IV), (RnNH4−n)2SnCl6: crystal structure, infrared spectrum, and hydrogen bonding

1983 ◽  
Vol 61 (7) ◽  
pp. 1620-1646 ◽  
Author(s):  
Osvald Knop ◽  
T. Stanley Cameron ◽  
Margaret Ann James ◽  
Michael Falk
Keyword(s):  
Hydrogen Bonding ◽  
Room Temperature ◽  
Fermi Resonance ◽  
Molecular Volume ◽  
Site Symmetry ◽  
Dilution Technique ◽  
Orientational Disorder ◽  
Anomalous Temperature ◽  
Ammonium Compounds ◽  
Anion Packing

In an effort to advance our understanding of the principles governing the structures of and the hydrogen bonding in alkylammonium hexachlorostannates(IV), (RnNH4−n)2SnCl6, we have determined the room-temperature crystal structures of (Me2NH2)2SnCl6 and (Me3NH)2SnCl6 (variants of the antifluorite structure); (EtNH3)2SnCl6 and (n-PrNH3)2SnCl6 (anti-Cdl2 type, with orientational disorder in the Et compound); and (n-Pr3NH)2SnCl6. We have also studied the infrared spectra in the regions of the NH and ND stretching fundamentals, between 10 and 293 K, of these five compounds and of (MeNH3)2SnCl6, (Me3NH)2SnBr6, (Et2NH2)2SnCl6, (n-Bu3NH)2SnCl6 and, in less detail, the mixed-anion salt (n-Pr2NH2)3(SnCl6)Cl. The spectra are often complicated by Ferim resonance involving absorptions diagnostically critical for the strength and type of [Formula: see text] bonding and for the site symmetry at the N atom. In this respect they are less useful than the corresponding spectra of the unsubstituted ammonium compounds reported previously. Several of the spectra provide striking examples of temperature-tuned Fermi resonance of NH and ND vibrations. The [Formula: see text] bonds are invariably trifurcated, bifurcated, or at least highly bent; these characteristics give rise to anomalous temperature dependence of the frequencies of the NH and ND stretching fundamentals. Temperature-induced transitions were detected in (Me2NH2)2SnCl6 (Ttr ~ 100 K), Et NH3)2SnCl6 (Ttr ~ 125 K), and (Et2NH2)2SnCl6 (Ttr ~ 330 K). The specific results for the ten compounds studied arc discussed in detail. The discussion also includes the limits of usefulness of the isotopisc dilution technique; symmetry aspects of the cation–anion packing in alkylammonium hexahalometallates(IV); symmetries of the arrangements of the SnCl6 octahedra; the geometry of hydrogen bonding in (RnNH4−n)2SnCl6; and the possibility of detection of the presence of hydrogen bonding from molecular volume trends.

scholarly journals Facet-specific interaction between methanol and TiO2 probed by sum-frequency vibrational spectroscopy

2018 ◽  
Vol 115 (17) ◽  
pp. E3888-E3894 ◽  
Author(s):  
Deheng Yang ◽  
Yadong Li ◽  
Xinyi Liu ◽  
Yue Cao ◽  
Yi Gao ◽  
...  
Keyword(s):  
Vibrational Spectroscopy ◽  
Molecular Form ◽  
Specific Interaction ◽  
Fermi Resonance ◽  
Free Energies ◽  
Sum Frequency ◽  
Resonance Coupling ◽  
Bending Modes ◽  
Titanium Dioxides

The facet-specific interaction between molecules and crystalline catalysts, such as titanium dioxides (TiO2), has attracted much attention due to possible facet-dependent reactivity. Using surface-sensitive sum-frequency vibrational spectroscopy, we have studied how methanol interacts with different common facets of crystalline TiO2, including rutile(110), (001), (100), and anatase(101), under ambient temperature and pressure. We found that methanol adsorbs predominantly in the molecular form on all of the four surfaces, while spontaneous dissociation into methoxy occurs preferentially when these surfaces become defective. Extraction of Fermi resonance coupling between stretch and bending modes of the methyl group in analyzing adsorbed methanol spectra allows determination of the methanol adsorption isotherm. The isotherms obtained for the four surfaces are nearly the same, yielding two adsorbed Gibbs free energies associated with two different adsorption configurations singled out by ab initio calculations. They are (i) ∼−20 kJ/mol for methanol with its oxygen attached to a low-coordinated surface titanium, and (ii) ∼−5 kJ/mol for methanol hydrogen-bonded to a surface oxygen and a neighboring methanol molecule. Despite similar adsorption energetics, the Fermi resonance coupling strength for adsorbed methanol appears to depend sensitively on the surface facet and coverage.

Temperature and Solvent Dependence of 13C—H Spin-Spin Coupling Constant JCH in Ethyl Formate

1968 ◽  
Vol 23 (12) ◽  
pp. 2094-2097 ◽  
Author(s):  
Erkki Rahkamaa ◽  
Jukka Jokisaari
Keyword(s):  
Hydrogen Bonding ◽  
Ethyl Formate ◽  
Spin Coupling ◽  
Intermolecular Hydrogen Bonding ◽  
Formyl Group ◽  
Coupling Constant ◽  
Spin Coupling Constant ◽  
Solvent Dependence ◽  
Pmr Spectra ◽  
Spin Spin Coupling

PMR spectra of pure ethyl formate and its solutions in carbon tetrachloride, carbon disulfide and acetone indicate that both the directly bonded 13C—H coupling constant and the chemical shift of the formyl group vary with temperature, solvent and concentration. Some aspects of the temperature and solvent dependence of JCH and δ can be related to the intermolecular hydrogen bonding involving the formyl proton. The possibility of the existence of other factors must however not be forgotten.

The influence of CH…π interaction on hydrogen bonding ability of –CONH2 functional group of benzamide

2016 ◽  
Vol 27 (4) ◽  
pp. 1199-1209 ◽  
Author(s):  
Zabihollah Momeni ◽  
Ali Ebrahimi
Keyword(s):  
Hydrogen Bonding ◽  
Functional Group

scholarly journals Crystal structure of 5,5′-bis(dimethylamino)-N,N′-(3-methyl-3-azapentane-1,5-diyl)di(naphthalene-1-sulfonamide)

2015 ◽  
Vol 71 (12) ◽  
pp. o959-o960 ◽  
Author(s):  
Toyketa V. Horne ◽  
Syed A. Haque ◽  
Adrianne Barton ◽  
Md. Alamgir Hossain
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Dihedral Angle ◽  
Tertiary Amine ◽  
Title Compound ◽  
Functional Group ◽  
Compound C ◽  
Hydrogen Bonding Interactions ◽  
Acceptor Atom ◽  
Dansyl Derivatives

In the title compound, C29H37N5O4S2, two arms substituted with dansyl derivatives are connected to a central tertiary amine, where the dihedral angle between the planes of two dansyl units is 56.39 (4)°. Each arm contains a sulfonamide functional group and both N—H groups in the compound are pointed to the same side. The central part of the molecule is disordered over three sets of sites with a refined occupancy ratio of 0.547 (4):0.328 (4):0.125 (3). No intramolecular π–π or hydrogen-bonding interactions are observed. In the crystal, molecules are linkedviapairs of N—H...O interactions involving the same acceptor atom, forming inversion dimers. In addition, C—H...O interactions exist between molecules, providing further stabilization of dimers.

Hydrogen bond induced enhancement of Fermi resonances in N–H⋯N hydrogen bonded complexes of anilines

2018 ◽  
Vol 20 (33) ◽  
pp. 21557-21566 ◽  
Author(s):  
Saurabh Mishra ◽  
Jer-Lai Kuo ◽  
G. Naresh Patwari
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Fermi Resonance ◽  
Alkyl Amines ◽  
Fermi Resonances ◽  
Bonded Complexes ◽  
Hydrogen Bonded

Enhancement of Fermi resonance intensities due to the formation of N–H⋯N hydrogen bonding of anilines with alkyl amines is analyzed using a two-state deperturbation model.

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