Intramolecular hydrogen bond and molecular conformation. Part 1.—Effect of pressure and temperature on the infrared spectra of 4-hydroxy-4-methylpentan-2-one (diacetone alcohol) in dilute solutions

1993 ◽  
Vol 89 (3) ◽  
pp. 489-493 ◽  
Author(s):  
Nozomu Kamiya ◽  
Takahiro Sekigawa ◽  
Shun-Ichi Ikawa
Keyword(s):  
Hydrogen Bond ◽  
Intramolecular Hydrogen Bond ◽  
Infrared Spectra ◽  
Molecular Conformation ◽  
Dilute Solutions ◽  
Effect Of Pressure ◽  
Diacetone Alcohol ◽  
Intramolecular Hydrogen

THE STUDY OF HYDROGEN BONDING AND RELATED PHENOMENA BY SPECTROSCOPIC METHODS: PART VIII. THE ULTRAVIOLET AND INFRARED SPECTRA OF SOME 2,4-DINITRODIPHENYLAMINES

1964 ◽  
Vol 42 (12) ◽  
pp. 2674-2683 ◽  
Author(s):  
A. Balasubramanian ◽  
J. B. Capindale ◽  
W. F. Forbes
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Spectral Data ◽  
Intramolecular Hydrogen Bond ◽  
Infrared Spectra ◽  
Positive Charge ◽  
Spectroscopic Methods ◽  
Amino Group ◽  
Strong Type ◽  
Intramolecular Hydrogen

The ultraviolet spectra of a number of 2,4-dinitrodiphenylamines suggest that these compounds are generally non-planar in a number of different solvents. The infrared and ultraviolet spectral data in different solvents also suggest that an intramolecular hydrogen bond is present in these molecules, at least in inert solvents. There is evidence that a p-nitro substituent is necessary to increase the positive charge on the amino group sufficiently to permit it to form this fairly strong type of hydrogen bond.

The Photolysis of Matrix Isolated cis-Thionylimide. 2. The Identification and Infrared Spectra of trans-HNSO and NSO

1975 ◽  
Vol 53 (15) ◽  
pp. 2331-2336 ◽  
Author(s):  
Peter O. Tchir ◽  
Richard D. Spratley
Keyword(s):  
Hydrogen Bond ◽  
Force Field ◽  
Intramolecular Hydrogen Bond ◽  
Infrared Spectra ◽  
Low Energy ◽  
Argon Matrix ◽  
Using Data ◽  
Argon Matrices ◽  
Intramolecular Hydrogen ◽  
Cis And Trans

It is shown that the low energy (λ > 3000 Å) photolysis of cis-HNSO in an argon matrix leads to formation of trans-HNSO. Four i.r. absorptions are observed and assigned for trans-HNSO and an approximate partial force field is calculated using data from isotopic substitutions. A comparison is made of the i.r. spectra of cis- and trans-HNSO using the intramolecular hydrogen bond of the cis form as a basis for explanation of the differences. Photolysis of cis-HNSO in argon matrices using vacuum u.v. light (1216 Å) has resulted in a single i.r. absorption at 1195 cm−1 which has been assigned to the radical, NSO.

scholarly journals C–H⋯F Hydrogen Bond and Integral Intensities of Vinyl C–H Vibtations in Push-Pull β-Dimethylaminotrifluoromethyl Ketone and Its Deuterated Analog

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Sergei Vdovenko ◽  
Igor Gerus ◽  
Elena Fedorenko ◽  
Valery Kukhar
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Dft Calculations ◽  
Intramolecular Hydrogen Bond ◽  
Infrared Spectra ◽  
Intermolecular Hydrogen Bond ◽  
Intermolecular Hydrogen Bonds ◽  
Accurate Analysis ◽  
Deuterated Analog ◽  
Intramolecular Hydrogen

The accurate analysis of infrared spectra (both wavenumbers and intensities) of (E)-4-(dimethylamino)-1,1,1-trifluorobut-3-en-2-one (DMTBN) and (E)-4-(hexadeutero-dimethylamino)-1,1,1-trifluorobut-3-en-2-one (d6-DMTBN) revealed that besides intramolecular hydrogen bond in the (EE) conformer, these enaminoketones form cyclic dimers between the (EZ) and (EE) conformers due to intermolecular hydrogen bonds, namely, O=C and . Evaluation of constant and enthalpy of formation of these H-bonds revealed that O=C bond has greater and more negative than bond (cf. 214.4 M−1, −21.7 kJ M−1dm3, and 16.4 M−1, −6.7 kJ M−1dm3, resp.). Consequently, stronger H-bond ⋯O=C is formed in the first place, whereas weaker H-bond is formed afterward. Moreover, formation of intermolecular hydrogen bond has influence on C–F vibrations, but analysis of this influence must take into account the fact that these vibrations in some cases are coupled with . True enthalpy of the equilibrium (EZ)⇌(EE) is positive (25.3 kJ M−1dm3), thus confirming results of DFT calculations, according to which the (EZ) conformer is more stable than the (EE) one.

Effect of the intramolecular hydrogen bond in the active metabolite analogs of leflunomide for blocking the Plasmodium falciparum dihydroorotate dehydrogenase enzyme: QTAIM, NBO, and docking study

2020 ◽  
Vol 16 ◽  
Author(s):  
Reihaneh Heidarian ◽  
Mansoureh Zahedi-Tabrizi
Keyword(s):  
Hydrogen Bond ◽  
Plasmodium Falciparum ◽  
Molecular Orbital ◽  
Intramolecular Hydrogen Bond ◽  
Active Metabolite ◽  
Chemical Hardness ◽  
Dihydroorotate Dehydrogenase ◽  
Molecular Orbital Analysis ◽  
Intramolecular Hydrogen ◽  
Orbital Analysis

: Leflunomide (LFM) and its active metabolite, teriflunomide (TFM), have drawn a lot of attention for their anticancer activities, treatment of rheumatoid arthritis and malaria due to their capability to inhibit dihydroorotate dehydrogenase (DHODH) and Plasmodium falciparum dihydroorotate dehydrogenase (PfDHODH) enzyme. In this investigation, the strength of intramolecular hydrogen bond (IHB) in five analogs of TFM (ATFM) has been analyzed employing density functional theory (DFT) using B3LYP/6-311++G (d, p) level and molecular orbital analysis in the gas phase and water solution. A detailed electronic structure study has been performed using the quantum theory of atoms in molecules (QTAIM) and the hydrogen bond energies (EHB) of stable conformer obtained in the range of 76-97 kJ/mol, as a medium hydrogen bond. The effect of substitution on the IHB nature has been studied by natural bond orbital analysis (NBO). 1H NMR calculations show an upward trend in the proton chemical shift of the enolic proton in the chelated ring (14.5 to 15.7ppm) by increasing the IHB strength. All the calculations confirmed the strongest IHB in 5-F-ATFM and the weakest IHB in 2-F-ATFM. Molecular orbital analysis, including the HOMO-LUMO gap and chemical hardness, was performed to compare the reactivity of inhibitors. Finally, molecular docking analysis was carried out to identify the potency of inhibition of these compounds against PfDHODH enzyme.

Far Infrared Group Frequencies. V. Oximes and Aldoximes

1973 ◽  
Vol 27 (1) ◽  
pp. 22-26 ◽  
Author(s):  
S. M. Craven ◽  
F. F. Bentley ◽  
D. F. Pensenstadler
Keyword(s):  
Hydrogen Bond ◽  
Infrared Spectra ◽  
Low Frequency ◽  
Far Infrared ◽  
Torsional Vibrations ◽  
Lattice Vibrations ◽  
Dilute Solutions ◽  
Solid Samples ◽  
Bending Modes ◽  
Bond Stretch

The low frequency infrared spectra from 450 to 75 cm−1 of seven oximes and five aldoximes have been recorded for pure samples and for dilute solutions in cyclohexane. An intense characteristic band is present in the solution spectra at 367 ± 10 cm−1. This characteristic band shifts to 275 ± 10 cm−1 in the spectra of the OD compounds. The 367 ± 10 cm−1 and 275 ± 10 cm−1 bands are assigned to OH and OD torsional vibrations. A comparison of the solution spectra with spectra of the solid samples indicated that the OH … N hydrogen bond stretch of oximes and aldoximes occurs in 300 to 200 cm−1 region. Strong bands also are present in 140 to 100 cm−1 region which are due to OH … N bending modes or perhaps lattice vibrations.

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