Absorption intensity changes and frequency shifts of fundamental and first overtone bands for OH stretching vibration of methanol upon methanol–pyridine complex formation in CCl4: analysis by NIR/IR spectroscopy and DFT calculations

2016 ◽  
Vol 18 (7) ◽  
pp. 5580-5586 ◽  
Author(s):  
Yoshisuke Futami ◽  
Yasushi Ozaki ◽  
Yukihiro Ozaki
Keyword(s):  
Hydrogen Bond ◽  
Ir Spectroscopy ◽  
Complex Formation ◽  
Dft Calculations ◽  
Frequency Shifts ◽  
Absorption Intensity ◽  
Pyridine Complex ◽  
Intensity Changes ◽  
Stretching Vibration

The first overtone of the OH stretching mode of the OH–N hydrogen bond of the methanol–pyridine complex was observed.

Basicity of fuchsones. Infrared study of the ν(OH) stretching vibration in phenol-fuchsone complexes

1981 ◽  
Vol 46 (8) ◽  
pp. 1818-1827
Author(s):  
Jiří Velek ◽  
Bohumír Koutek ◽  
Lubomír Musil ◽  
Soňa Vašíčková ◽  
Milan Souček
Keyword(s):  
Hydrogen Bond ◽  
Carbonyl Oxygen ◽  
Steric Factor ◽  
Hydrogen Bond Energy ◽  
Infrared Study ◽  
Frequency Shifts ◽  
Linear Free Energy ◽  
Stretching Vibration ◽  
Energy Relationships ◽  
Integrated Intensities

The hydrogen bond complexes involving phenol and carbonyl oxygen of 2- and 2,6-substituted fuchsones I and II have been studied by infrared spectroscopy in tetrachlorethylene solution. Basicities expressed as complexation enthalpies, frequency shifts and integrated intensities of the ν(OH) stretching vibrations are reported. A linear relationship was found between the frequency shift and the hydrogen bond energy. Statistical analysis of linear free energy relationships for fuchsones I and II proved the significancy of steric factor in transmission of electronic substituent effect.

Anion effect on alkali ion-crown complex formation in a moderately concentrated solutions: A sensitive probe of hidden interionic interactions operating in dissociating protic solvents

1990 ◽  
Vol 55 (5) ◽  
pp. 1149-1161
Author(s):  
Jiří Závada ◽  
Václav Pechanec ◽  
Oldřich Kocián
Keyword(s):  
Hydrogen Bond ◽  
Complex Formation ◽  
Charge Density ◽  
Macrocyclic Ligand ◽  
Simple Explanation ◽  
Anion Effect ◽  
Protic Solvents ◽  
The Individual ◽  
Alkali Salts ◽  
Alkali Ion

A powerful anion effect destabilizing alkali ion-crown complex formation has been found to operate in moderately concentrated protic (H2O, CH3OH, C2H5OH) solution, following the order HO- > AcO- > Cl- > Br- > NO3- > I- > NCS-. Evidence is provided that the observed effect does not originate from ion-pairing. A simple explanation is provided in terms of concordant hydrogen bond bridges of exalted stability between the gegenions, M+···OR-H···(OR-H)n···OR-H···A-. It is proposed that encapsulation of alkali ion by the macrocyclic ligand leads to a dissipation of the cation charge density destroying its ability to participate in the hydrogen bond bridge. An opposition against the alkali ion-crown complex formation arises accordingly in the solution in dependence on strength of the hydrogen bridge; for a given cation, the hydrogen bond strength increases with increasing anion charge density from NCS- to HO-(RO-). It is pointed out, at the same time, that the observed anion effect does not correlate with the known values of activity coefficients of the individual alkali salts which are almost insensitive to anion variation under the investigated conditions. As a resolution of the apparent paradoxon it is proposed that, in absence of the macrocyclic ligand, the stabilizing (concordant) bonding between the gegenions is nearly balanced by a destabilizing (discordant) hydrogen bonding between the ions of same charge (co-ions). Intrinsic differences among the individual salts are thus submerged in protic solvents and become apparent only when the concordant bonding is suppressed in the alkali ion-crown complex formation.

scholarly journals Cooperation/Competition between Halogen Bonds and Hydrogen Bonds in Complexes of 2,6-Diaminopyridines and X-CY3 (X = Cl, Br; Y = H, F)

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 766
Author(s):  
Barbara Bankiewicz ◽  
Marcin Palusiak
Keyword(s):  
Complex Formation ◽  
Hydrogen Bonds ◽  
Dft Calculations ◽  
Electrostatic Interactions ◽  
Dipole Moments ◽  
Main Role ◽  
Halogen Bonds ◽  
Topological Parameters ◽  
Leading Role ◽  
The Impact

The DFT calculations have been performed on a series of two-element complexes formed by substituted 2,6-diaminopyridine (R−PDA) and pyridine (R−Pyr) with X−CY3 molecules (where X = Cl, Br and Y = H, F). The primary aim of this study was to examine the intermolecular hydrogen and halogen bonds in the condition of their mutual coexistence. Symmetry/antisymmetry of the interrelation between three individual interactions is addressed. It appears that halogen bonds play the main role in the stabilization of the structures of the selected systems. However, the occurrence of one or two hydrogen bonds was associated with the favourable geometry of the complexes. Moreover, the impact of different substituent groups attached in the para position to the aromatic ring of the 2,6-diaminopyridine and pyridine on the character of the intermolecular hydrogen and halogen bonds was examined. The results indicate that the presence of electron-donating substituents strengthens the bonds. In turn, the presence of electron-withdrawing substituents reduces the strength of halogen bonds. Additionally, when hydrogen and halogen bonds lose their leading role in the complex formation, the nonspecific electrostatic interactions between dipole moments take their place. Analysis was based on geometric, energetic, and topological parameters of the studied systems.

The resonance Raman spectra and excitation profiles of some 4-sulfamylazobenzenes

1977 ◽  
Vol 55 (9) ◽  
pp. 1444-1453 ◽  
Author(s):  
Kamal Kumar ◽  
P. R. Carey
Keyword(s):  
Raman Spectrum ◽  
Raman Spectra ◽  
Resonance Raman ◽  
Valence Bond ◽  
Wavelength Dependence ◽  
Accurate Estimation ◽  
Intensity Changes ◽  
Stretching Vibration ◽  
Resonance Raman Spectra ◽  
Frequency Changes

The resonance Raman spectra of three pharmacologically important sulfonamides, 4-sulfamyl-4′-dimethylaminoazobenzene (1), 4-sulfamyl-4′-hydroxyazobenzene (2), and 4-sulfamyl-4′-aminoazobenzene (3), are compared with those of analogues lacking the sulfonamide group. The —SO2NH2 moiety does not directly contribute intense or moderately intense bands to the resonance Raman spectra of 1, 2, and 3. However, —SO2NH2 ionization is reflected by frequency changes in a band near 1140 cm−1 and intensity changes in the 1420 cm−1 region. The normal Raman spectrum of 2 confirms that the intensity changes reflect —SO2NH2 ionization rather than unrelated changes in vibronic coupling. The effect of —OH ionization on the resonance Raman spectrum of 2 emphasizes that caution must be exercised when relating spectral perturbations to changes in contributions from valence bond type structures. Resonance Raman excitation profiles for the 1138, 1387, and 1416 cm−1 bands of 2 show that these bands gain intensity by coupling with the electronic transitions in the 240 to 450 nm region and that, more than 1000 cm−1 to the red of λmax, the wavelength dependence can be closely reproduced by the FB type terms of Albrecht and Hutley. The excitation profile for each band shows evidence for structure in the 470 nm region, although lack of sufficient excitation wavelengths prevents accurate estimation of the spacing. Under conditions of rigorous resonance the intense Raman lines all occur in the 1400 cm−1 region, i.e. they are 'bunched' in the region known to contain the —N=N— stretching vibration.

Simultaneous membrane transport of two active pharmaceutical ingredients by charge assisted hydrogen bond complex formation

2014 ◽  
Vol 5 (9) ◽  
pp. 3449 ◽  
Author(s):  
Hui Wang ◽  
Gabriela Gurau ◽  
Julia Shamshina ◽  
O. Andreea Cojocaru ◽  
Judith Janikowski ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Complex Formation ◽  
Membrane Transport ◽  
Active Pharmaceutical Ingredients ◽  
Pharmaceutical Ingredients

Surface Acidity and Basicity of La2O3, LaOCl, and LaCl3 Characterized by IR Spectroscopy, TPD, and DFT Calculations.

ChemInform ◽  
2004 ◽  
Vol 35 (51) ◽  
Author(s):  
Olga V. Manoilova ◽  
Simon G. Podkolzin ◽  
Balarishna Tope ◽  
Johannes Lercher ◽  
Eric E. Stangland ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Dft Calculations ◽  
Surface Acidity ◽  
Acidity And Basicity

scholarly journals Ligand-induced decarbonylation in diphosphine-ligated palladium acetates [CH3CO2Pd((PR2)2CH2)]+ (R = Me and Ph)

2018 ◽  
Vol 54 (4) ◽  
pp. 346-349 ◽  
Author(s):  
Michael Lesslie ◽  
Yang Yang ◽  
Allan J. Canty ◽  
Elettra Piacentino ◽  
Francis Berthias ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Dft Calculations ◽  
Isotope Labelling

Isotope labelling, IR spectroscopy and DFT calculations reveal a novel ligand-induced decarbonylation reaction.

Dynamic Fourier Transform Polarized Raman Spectroscopy of Polyethylene Fibers under a Modulated Strain

2002 ◽  
Vol 56 (7) ◽  
pp. 809-812 ◽  
Author(s):  
P. R. Griffiths ◽  
D. B. Chase ◽  
R. M. Ikeda ◽  
J. W. Catron
Keyword(s):  
Raman Spectroscopy ◽  
Tensile Deformation ◽  
Infrared Transmission ◽  
Polymeric Fibers ◽  
Frequency Shifts ◽  
Infrared Measurements ◽  
Intensity Changes ◽  
Ft Raman Spectroscopy ◽  
Polarized Raman ◽  
Polyethylene Fibers

The response of materials under stress is a critical aspect of the in-use performance of fibers and films. Dynamic infrared measurements have been shown to be very informative and have provided information about both chain reorientation and conformational state change during deformation. However, the use of infrared transmission techniques necessarily confines the measurements to thin films. Polymeric fibers present a real challenge to this approach. Raman scattering is extremely well suited for fibers. There is no real constraint on sample size, shape, or thickness. Dynamic measurements on fibers under deformation have been extended using a Raman probe. Step-scan FT-Raman spectroscopy has allowed the decoupling of the sample strain frequencies from the Fourier frequencies, and the sensitivity is sufficient to observe the small changes associated with an elastic tensile deformation. For polyethylene fibers, the dynamic spectra exhibit both stress-induced frequency shifts and intensity changes due to chain reorientation. Vibrational modes that are coupled to chain backbone motions are found to exhibit the strongest stress-induced frequency shifts, while decoupled motions, such as C–H stretching modes, exhibit the effects of chain reorientation.

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