Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

¹H NMR of Labile Protons: Temporal Resolution01:10

¹H NMR of Labile Protons: Temporal Resolution

1.4K
Protons bonded to heteroatoms such as nitrogen and oxygen exhibit a range of chemical shift values. This is due to the varying degree of hydrogen bonding between the proton and the heteroatom in other molecules. The extent of hydrogen bonding affects the electron density around the proton, thereby giving different chemical shift values for the protons in the proton NMR spectrum.
The –OH proton in alcohols typically appears in the range of δ 2 to 5 ppm but can vary depending on the...
1.4K
Proton (¹H) NMR: Chemical Shift01:07

Proton (¹H) NMR: Chemical Shift

3.8K
Organic molecules primarily contain carbon and hydrogen atoms. While all the hydrogen isotopes are NMR-active, protium or hydrogen-1 is the most abundant. It has a significant energy separation between its nuclear spin states due to its large gyromagnetic ratio. As per Boltzmann's distribution, an increase in the energy separation implies a greater excess population of nuclei available for excitation, resulting in a strong NMR absorption signal.
Absorption signals of all the protium nuclei...
3.8K
¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)01:20

¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)

1.3K
When proton-coupled carbon-13 spectra are simplified by a broadband proton decoupling technique, structural information about the coupled protons is lost. Distortionless enhancement by polarization transfer (DEPT) is a technique that provides information on the number of hydrogens attached to each carbon in a molecule. While the DEPT experiment utilizes complex pulse sequences, the pulse delay and flip angle are specifically manipulated. The resulting signals have different phases depending on...
1.3K
¹H NMR: Complex Splitting01:13

¹H NMR: Complex Splitting

1.7K
A proton M that is coupled to a proton X results in doublet signals for M. However, NMR-active nuclei can be simultaneously coupled to more than one nonequivalent nucleus. When M is coupled to a second proton A, such as in styrene oxide, each peak in the doublet is split into another doublet.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
1.7K
¹H NMR of Conformationally Flexible Molecules: Temporal Resolution00:52

¹H NMR of Conformationally Flexible Molecules: Temporal Resolution

992
At room temperature, the chair conformer of cyclohexane undergoes rapid ring flipping between two equivalent chair conformers at a rate of approximately 105 times per second. These two chair conformers are in equilibrium. The rapid ring flipping results in the interconversion of the axial proton to an equatorial proton and an equatorial to the axial proton. Such interconversions are too rapid and cannot be detected on the NMR timescale. Hence, the NMR spectrometer cannot distinguish between the...
992
Interpreting ¹H NMR Signal Splitting: The (n + 1) Rule01:10

Interpreting ¹H NMR Signal Splitting: The (n + 1) Rule

2.9K
In the AX proton spin system, proton A can sense the two spin states of a coupled proton X, resulting in a doublet NMR signal with two peaks of equal (1:1) intensity. When proton A is coupled to two equivalent protons (AX2 spin system), the spin states of each X can be aligned with or against the external field, creating three possible scenarios. This results in a 1:2:1  triplet signal, where the central peak corresponds to the chemical shift of A and is twice as large or intense as the...
2.9K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Unravelling the amplified spontaneous emission mechanism in three-dimensional metal halide perovskites.

Nanoscale·2026
Same author

Exploring potential reactivity by optical polarization dependent coherent vibrational spectroscopy.

The Journal of chemical physics·2025
Same author

Femtosecond spectroscopy with paired single photons: Emulating a double-slit experiment in the time-frequency domain.

Science advances·2025
Same author

Understanding contrasting S<sub>2</sub> → S<sub>1</sub> internal conversion rates in boron-dipyrromethene derivatives <i>via</i> multi-configuration time-dependent hartree method.

Physical chemistry chemical physics : PCCP·2025
Same author

Desymmetrization on electron-withdrawing groups in single benzene fluorophores for fine tuning of photophysical properties and applications.

RSC advances·2025
Same author

Stimuli-Responsive DNA Hydrogel Design Strategies for Biomedical Applications.

Biosensors·2025

Related Experiment Video

Updated: Apr 30, 2026

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy
10:03

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy

Published on: June 27, 2014

18.6K

Quantum-Indeterminate Proton Positions in Ultrafast Excited-State Intramolecular Proton Transfer.

Minhyuk Lee1, Changmin Lee2, JunWoo Kim1

  • 1Department of Chemistry, Chungbuk National University, Cheongju 28644, Republic of Korea.

The Journal of Physical Chemistry Letters
|April 29, 2026
PubMed
Summary

Coherent vibrational spectroscopy reveals that only one of two proton transfers in BP(OH)2 shows quantum vibrational signatures, challenging semiclassical models of excited-state intramolecular proton transfer (ESIPT). This highlights quantum effects in ultrafast chemical reactions.

More Related Videos

Isotopic Effect in Double Proton Transfer Process of Porphycene Investigated by Enhanced QM/MM Method
05:51

Isotopic Effect in Double Proton Transfer Process of Porphycene Investigated by Enhanced QM/MM Method

Published on: July 19, 2019

5.8K
Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
08:22

Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization

Published on: August 6, 2018

6.5K

Related Experiment Videos

Last Updated: Apr 30, 2026

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy
10:03

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy

Published on: June 27, 2014

18.6K
Isotopic Effect in Double Proton Transfer Process of Porphycene Investigated by Enhanced QM/MM Method
05:51

Isotopic Effect in Double Proton Transfer Process of Porphycene Investigated by Enhanced QM/MM Method

Published on: July 19, 2019

5.8K
Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
08:22

Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization

Published on: August 6, 2018

6.5K

Area of Science:

  • Physical Chemistry
  • Quantum Mechanics
  • Spectroscopy

Background:

  • Nuclear motion in condensed-phase chemistry is often treated semiclassically due to experimental challenges in observing quantum behavior.
  • Excited-state intramolecular proton transfer (ESIPT) offers a window into quantum regimes before perturbations.
  • The molecule [2,2'-bipyridyl]-3,3'-diol (BP(OH)2) facilitates double proton transfer, making it a model system.

Purpose of the Study:

  • To investigate the ultrafast dynamics of double proton transfer in BP(OH)2.
  • To probe quantum mechanical aspects of nuclear motion during ESIPT.
  • To utilize coherent vibrational spectroscopy for observing proton-transfer-induced vibrations.

Main Methods:

  • Coherent vibrational spectroscopy was employed to study the ESIPT dynamics of BP(OH)2.
  • The study focused on observing vibrational coherences resulting from proton transfer events.
  • Analysis aimed to differentiate between semiclassical and quantum mechanical descriptions of the nuclear motion.

Main Results:

  • Only one of the two proton transfer events in BP(OH)2 exhibited a proton-transfer-induced coherent vibration.
  • The second proton transfer event showed no evidence of a coherent vibrational response linked to proton transfer.
  • These findings deviate from predictions based on a simple semiclassical model of sequential proton transfer.

Conclusions:

  • The observed asymmetry in vibrational response challenges straightforward semiclassical explanations for sequential proton transfer.
  • Coherent vibrational spectroscopy is a powerful tool for uncovering subtle quantum phenomena in ultrafast chemical reactions.
  • The study underscores the importance of quantum mechanics in understanding complex proton transfer dynamics.