scholarly journals Intramolecular hydrogen tunneling in 2-chloromalonaldehyde trapped in solid para-hydrogen

2020 ◽  
Vol 22 (11) ◽  
pp. 6115-6121
Author(s):  
Alejandro Gutiérrez-Quintanilla ◽  
Michèle Chevalier ◽  
Rasa Platakyte ◽  
Justinas Ceponkus ◽  
Claudine Crépin
Keyword(s):  
Para Hydrogen ◽  
Hydrogen Tunneling ◽  
Tunneling Process ◽  
Vibrational Levels ◽  
Intramolecular Hydrogen ◽  
Insight Into

Trapping 2-chloromalonaldehyde in solid para-hydrogen is used for a powerful insight into the H-tunneling process at various vibrational levels.

Through-Space Transmission of 19F-13C Coupling Via an Intermediate Bond. An Experimental and Theoretical Study

1987 ◽  
Vol 40 (12) ◽  
pp. 1923 ◽  
Author(s):  
ID Rae ◽  
ID Rae ◽  
A Staffa ◽  
A Staffa ◽  
AC Diz ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Lone Pair ◽  
Electron Excitation ◽  
Carbonyl Groups ◽  
Polarization Propagator ◽  
Close Proximity ◽  
Fermi Contact ◽  
Intramolecular Hydrogen ◽  
Intermediate Bond ◽  
Insight Into

In order to obtain a deeper insight into the title effect, several compounds with an F atom very close to a C-H of a nearby functional group were synthesized and the relevant couplings measured. The most conspicuous case was that of 8-fluoro-2-hydroxynaphthalene-1-carbaldehyde where a close proximity between the F and H atoms is the result of fluorine-oxygen repulsion and the formation of an intramolecular hydrogen bond between the hydroxyl and carbonyl groups. The experimental four-bond J(F,CHO) coupling is 26.2 Hz. A compound very similar to this one, but without the OH group, was chosen on which to perform a polarization propagator analysis of the through-space (TS) coupling pathways, at the RPA-INDO level. The expression for the TS coupling in terms of the projected polarization propagator and perturbators was numerically analysed. It is found that this coupling is completely dominated by a TS component of the Fermi contact (FC) term, the main features of which are: ( i ) It decays exponentially with the F-H distance; (ii) Its main contribution comes from an electron excitation involving the F lone-pair, the C-H bond of the CHO moiety and its corresponding antibonding orbital;(iii) The π-type lone-pair does not contribute to the TS coupling pathway of the FC term.

The spectroscopy of jet-cooled porphyrins: an insight into the vibronic structure of the Q band

2010 ◽  
Vol 14 (04) ◽  
pp. 314-323 ◽  
Author(s):  
Joseph M. Beames ◽  
Timothy D. Vaden ◽  
Andrew J. Hudson
Keyword(s):  
Laser Desorption ◽  
Electronic Transitions ◽  
Quantum Mechanical ◽  
Supersonic Expansion ◽  
Two Photon ◽  
Vibrational Levels ◽  
Inert Carrier ◽  
Mechanical Interpretation ◽  
Photon Ionization ◽  
Insight Into

We will present resonant two-photon ionization spectra for meso-tetraphenylporphyrin, H 2 TPP , measured under isolated conditions. The polycrystalline compound was vaporized, in vacuo, using both thermal and laser desorption, and seeded into a supersonic expansion of an inert-carrier gas. The molecules remain largely intact in the gaseous phase. However, the two techniques for vaporizing H 2 TPP give different internal temperatures for the isolated substrate, with greater vibrational cooling achieved using laser desorption. A comparison of the peak positions and intensities in the resonant two-photon ionization spectra of thermal- and laser-desorbed molecules provides an insight into the vibrational structure of the Q band. In particular, the greater contribution made by electronic transitions originating from higher vibrational levels in the ground state of H 2 TPP is emphasized. We conclude that vibronic coupling in the ground electronic state plays an important role in a quantum-mechanical interpretation of the Q band.

Internal Rotation and Spin Conversion of CH3OH in Solid para-Hydrogen

Science ◽  
2006 ◽  
Vol 311 (5759) ◽  
pp. 365-368 ◽  
Author(s):  
Yuan-Pern Lee ◽  
Yu-Jong Wu ◽  
R. M. Lees ◽  
Li-Hong Xu ◽  
Jon T. Hougen
Keyword(s):  
Internal Rotation ◽  
Nuclear Spin ◽  
Spin Symmetry ◽  
Spectral Lines ◽  
High Resolution Spectrum ◽  
Para Hydrogen ◽  
Spin Conversion ◽  
Host Matrix ◽  
Matrix Isolation Spectroscopy ◽  
Insight Into

The quantum solid para-hydrogen (p-H2) has recently proven useful in matrix isolation spectroscopy. Spectral lines of compounds embedded in this host are unusually narrow, and several species have been reported to rotate in p-H2. We found that a p-H2 matrix inhibits rotation of isolated methanol (CH3OH) but still allows internal rotation about the C–O bond, with splittings of the E/A torsional doublet in internal rotation–coupled vibrational modes that are qualitatively consistent with those for CH3OH in the gaseous phase. This simplified high-resolution spectrum further revealed the slow conversion of nuclear spin symmetry from species E to species A in the host matrix, offering potential insight into nuclear spin conversion in astrophysical sources.

An insight into the extraction of transition metal ions by picolinamides associated with intramolecular hydrogen bonding and rotational isomerization

RSC Advances ◽  
2014 ◽  
Vol 4 (56) ◽  
pp. 29702-29714 ◽  
Author(s):  
Yan Li ◽  
Yiming Jia ◽  
Zhenwen Wang ◽  
Xianghui Li ◽  
Wen Feng ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Transition Metal ◽  
Metal Ions ◽  
Intramolecular Hydrogen Bonding ◽  
Transition Metal Ions ◽  
Intramolecular Hydrogen ◽  
Insight Into

Disruption of intramolecular H-bonding via N-substitution leads to rotational isomerization and much improvement in extraction of Hg2+.

The Change in the Nature of the Chemical Bond through Hydrogen Tunneling Process in BN‐Ethylamine

2019 ◽  
Vol 4 (47) ◽  
pp. 13867-13875 ◽  
Author(s):  
Alejandro Lopez‐Castillo ◽  
Nelson H. Morgon
Keyword(s):  
Chemical Bond ◽  
Hydrogen Tunneling ◽  
Tunneling Process

scholarly journals Using coligands to gain mechanistic insight into iridium complexes hyperpolarized with para-hydrogen

2019 ◽  
Vol 10 (20) ◽  
pp. 5235-5245 ◽  
Author(s):  
Ben. J. Tickner ◽  
Richard O. John ◽  
Soumya S. Roy ◽  
Sam J. Hart ◽  
Adrian C. Whitwood ◽  
...  
Keyword(s):  
Ligand Exchange ◽  
Iridium Complexes ◽  
Para Hydrogen ◽  
Mechanistic Insight ◽  
Exchange Processes ◽  
Insight Into

Hyperpolarised iridium carboxyimine complexes yield diagnostic signals whilst undergoing ligand exchange processes rationalised by NMR and DFT.

Intramolecular hydrogen tunneling in malonaldehyde

1978 ◽  
Vol 100 (17) ◽  
pp. 5265-5267 ◽  
Author(s):  
Eugene M. Fluder ◽  
Jose R. De la Vega
Keyword(s):  
Hydrogen Tunneling ◽  
Intramolecular Hydrogen
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