Hydrogen bonding and vapor pressure isotope effect of ethanethiol

1979 ◽  
Vol 57 (11) ◽  
pp. 1350-1353 ◽  
Author(s):  
Jerzy Szydlowski ◽  
Hans Wolff
Keyword(s):  
Hydrogen Bonding ◽  
Vapor Pressure ◽  
Isotope Effect ◽  
Inverse Effect ◽  
Apparent Decrease ◽  
Stretching Vibrations ◽  
Intermolecular Vibrations ◽  
Hydrogen Bonded

The vapor pressure ratios of ethanethiol and ethanethiol-d1 between 223 and 323 K can be represented by the relation[Formula: see text]The PD/PH vs. T curve increases initially and reaches a flat maximum at 293 K; at higher temperatures there is an apparent decrease. This behavior can be explained by the superposition of predominantly the normal effect of the intermolecular vibrations and the SH and SD torsion vibrations, and the inverse effect of the SH and SD stretching vibrations. Contrary to the value of 0.91 reported previously, PD/PH values of 1.002 to 1.008 confirm that for weakly hydrogen-bonded substances and their deuterium-bonded analogues a negligibly normal or a slightly inverse vapor pressure isotope effect should be observed.

Raman and infrared spectroscopic study of the vivianite-group phosphates vivianite, baricite and bobierrite

2002 ◽  
Vol 66 (6) ◽  
pp. 1063-1073 ◽  
Author(s):  
R. L. Frost ◽  
W. Martens ◽  
P. A. Williams ◽  
J. T. Kloprogge
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bonding ◽  
Water Molecules ◽  
Infrared Spectroscopic Study ◽  
Tetrahedral Symmetry ◽  
Phosphate Anions ◽  
Stretching Vibrations ◽  
Bending Modes ◽  
Ir Bands ◽  
Hydrogen Bonded

Abstract The molecular structure of the three vivianite-structure, compositionally related phosphate minerals vivianite, baricite and bobierrite of formula M32+(PO4)2.8H2O where M is Fe or Mg, has been assessed using a combination of Raman and infrared (IR) spectroscopy. The Raman spectra of the hydroxyl-stretching region are complex with overlapping broad bands. Hydroxyl stretching vibrations are identified at 3460, 3281, 3104 and 3012 cm−1 for vivianite. The high wavenumber band is attributed to the presence of FeOH groups. This complexity is reflected in the water HOH-bending modes where a strong IR band centred around 1660 cm−1 is found. Such a band reflects the strong hydrogen bonding of the water molecules to the phosphate anions in adjacent layers. Spectra show three distinct OH-bending bands fromstrongly hydrogen-bonded, weakly hydrogen bonded water and non-hydrogen bonded water. The Raman phosphate PO-stretching region shows strong similarity between the three minerals. In the IR spectra, complexity exists with multiple antisymmetric stretching vibrations observed, due to the reduced tetrahedral symmetry. This loss of degeneracy is also reflected in the bending modes. Strong IR bands around 800 cm−1 are attributed to water librational modes. The spectra of the three minerals display similarities due to their compositions and crystal structures, but sufficient subtle differences exist for the spectra to be useful in distinguishing the species.

Model Calculations on the Influence of Mechanical and Electrical Anharmonicity on Infrared Intensities: Relation to Hydrogen Bonding

1972 ◽  
Vol 50 (19) ◽  
pp. 3161-3166 ◽  
Author(s):  
Thérèse Di Paolo ◽  
C. Bourdéron ◽  
C. Sandorfy
Keyword(s):  
Hydrogen Bonding ◽  
Dipole Moment ◽  
Model Calculations ◽  
First Derivative ◽  
Infrared Intensities ◽  
Stretching Vibrations ◽  
Hydrogen Bonded Systems ◽  
Hydrogen Bonded

The influence of mechanical and electrical anharmonicity on the intensity of X—H stretching vibrations is investigated by means of model calculations in relation to hydrogen bonding. It is found that while both kinds of anharmonicities have a significant effect on the intensity, they cannot explain the characteristic increase in intensity of the fundamental and the equally characteristic decrease in the intensity of the first overtone. It is shown that not only the first but both these phenomena are due to the large value of the first derivative of the dipole moment in hydrogen bonded systems. This is linked to the possibility that the effect of electrical anharmonicity (d2μ/dQ2) might be cancelled by a high value of (dμ/dQ)c in the expression of the overtone intensity.

Hydrogen bonding and vapor pressure isotope effect of deuterioisomeric methanethiols

1981 ◽  
Vol 85 (8) ◽  
pp. 1047-1051 ◽  
Author(s):  
Hans Wolff ◽  
Jerzy Szydlowski ◽  
Ludmilla Dill-Staffenberger
Keyword(s):  
Hydrogen Bonding ◽  
Vapor Pressure ◽  
Isotope Effect

Theoretical study of hydrogen bonding interactions in substituted nitroxide radicals

2021 ◽  
Author(s):  
Thufail M. Ismail ◽  
Neetha Mohan ◽  
P. K. Sajith
Keyword(s):  
Hydrogen Bonding ◽  
Interaction Energy ◽  
Electrostatic Potential ◽  
Molecular Electrostatic Potential ◽  
Theoretical Study ◽  
Nitroxide Radicals ◽  
Hydrogen Bonding Interactions ◽  
Bonded Complexes ◽  
Hydrogen Bonded

Interaction energy (Eint) of hydrogen bonded complexes of nitroxide radicals can be assessed in terms of the deepest minimum of molecular electrostatic potential (Vmin).

Understanding water structure from Raman spectra of isotopic substitution H2O/D2O up to 573 K

2017 ◽  
Vol 19 (32) ◽  
pp. 21540-21547 ◽  
Author(s):  
Qingcheng Hu ◽  
Haiwen Zhao ◽  
Shunli Ouyang
Keyword(s):  
Hydrogen Bonding ◽  
Raman Spectra ◽  
Water Structure ◽  
Free Water ◽  
Isotopic Substitution ◽  
Structure Model ◽  
Single Donor ◽  
Hydrogen Bonded

The OH/OD stretch band features on Raman spectra of isotopic substitution H2O/D2O at temperatures up to 573 K are correlated with a multi-structure model that water has five dominant hydrogen bonding configurations: tetrahedral, deformed tetrahedral, single donor, single hydrogen bonded water and free water.

Concomitant polymorphs of 1,3-bis(3-fluorophenyl)urea

2016 ◽  
Vol 72 (9) ◽  
pp. 692-696 ◽  
Author(s):  
Christina A. Capacci-Daniel ◽  
Jeffery A. Bertke ◽  
Shoaleh Dehghan ◽  
Rupa Hiremath-Darji ◽  
Jennifer A. Swift
Keyword(s):  
Hydrogen Bonding ◽  
Crystal Engineering ◽  
Structural Motif ◽  
Parallel Orientation ◽  
One Dimensional ◽  
Monoclinic Form ◽  
Engineering Studies ◽  
Hydrogen Bonded

Hydrogen bonding between urea functionalities is a common structural motif employed in crystal-engineering studies. Crystallization of 1,3-bis(3-fluorophenyl)urea, C13H10F2N2O, from many solvents yielded concomitant mixtures of at least two polymorphs. In the monoclinic form, one-dimensional chains of hydrogen-bonded urea molecules align in an antiparallel orientation, as is typical of many diphenylureas. In the orthorhombic form, one-dimensional chains of hydrogen-bonded urea molecules have a parallel orientation rarely observed in symmetrically substituted diphenylureas.

HYDROGEN BONDING IN DIASTEREOISOMERIC α-β AMINOALCOHOLS: A REINVESTIGATION OF THE EPHEDRINES BY N.M.R

1960 ◽  
Vol 38 (1) ◽  
pp. 125-130 ◽  
Author(s):  
James B. Hyne
Keyword(s):  
Hydrogen Bonding ◽  
Polar Solvents ◽  
Relative Stabilities ◽  
Hydrogen Bonded

The results of an n.m.r. study of the diastereoisomeric ephedrine and ψ-ephedrine molecules in non-polar solvents are interpreted and discussed in terms of the relative stabilities of the intramolecularly hydrogen-bonded conformers.

Sign in / Sign up

Export Citation Format

Share Document