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

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 specific...
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR01:15

¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR

The axial and equatorial protons in cyclohexane can be distinguished by performing a variable-temperature NMR experiment. In this process, except for one proton, the remaining eleven protons are replaced by deuterium. The deuterium substitution avoids the possible peak splitting caused by the spin-spin coupling between the adjacent protons. The remaining proton flips between the axial and equatorial positions.
Proton (¹H) NMR: Chemical Shift01:07

Proton (¹H) NMR: Chemical Shift

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 in a...
Inductive Effects on Chemical Shift: Overview01:27

Inductive Effects on Chemical Shift: Overview

The protons in unsubstituted alkanes are strongly shielded with chemical shifts below 1.8 ppm. Methine, methylene, and methyl protons appear at approximately 1.7, 1.2 and 0.7 ppm, while the proton signal from methane appears at 0.23 ppm. An electronegative substituent, such as chlorine, withdraws the electron density from the protons, increasing their chemical shift. Progressive substitution of the hydrogens in methane by chlorine shifts the proton signals increasingly downfield, to 3.05 ppm in...
Solvating Effects02:12

Solvating Effects

An understanding of the solvating effect helps rationalize the relation between solvation and acidity of the compound. In addition, this also explains the relative stability of conjugate bases for compounds with different pKa values. This lesson details, in-depth, the principle of solvating effects. The strength of an acid and the stability of its corresponding conjugate base are determined using pKa values. This observed relationship is a consequence of solvation, which is the interaction...
Comparing Intermolecular Forces: Melting Point, Boiling Point, and Miscibility02:34

Comparing Intermolecular Forces: Melting Point, Boiling Point, and Miscibility

Intermolecular forces are attractive forces that exist between molecules. They dictate several bulk properties, such as melting points, boiling points, and solubilities (miscibilities) of substances. Molar mass, molecular shape, and polarity affect the strength of different intermolecular forces, which influence the magnitude of physical properties across a family of molecules.
Temporary attractive forces like dispersion are present in all molecules, whether they are polar or nonpolar. They...

You might also read

Related Articles

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

Sort by
Same author

Unraveling the antioxidant and prooxidant mechanisms of methyl pro-lithospermate: a DFT and thermodynamic analysis in polar media.

Journal of molecular modeling·2026
Same author

[Be(NH<sub>3</sub>)<sub>16</sub>]<sup>[2]</sup> <sup>+</sup> Microsolvation: Structure, Energetics, and Temperature Effects.

Chemphyschem : a European journal of chemical physics and physical chemistry·2025
Same author

Discovery of novel Plasmodium falciparum PfDHFR-TS inhibitors from ConMedNP natural compounds: a multi-computational approach.

Molecular diversity·2025
Same author

Microhydration of phenylboronic acid and its hydration free energy.

Journal of molecular modeling·2025
Same author

Structures and Solvation Energies Effects Versus Temperature. An MP2 Investigations in the Framework of Cluster Model.

Journal of computational chemistry·2025
Same author

Intermolecular interactions in water and ethanol solution of ethyl acetate: Raman, DFT, MEP, FMO, AIM, NCI-RDG, ELF, and LOL analyses.

Journal of molecular modeling·2024

Related Experiment Video

Updated: May 11, 2026

Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry
12:11

Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry

Published on: April 8, 2020

Structures of protonated methanol clusters and temperature effects.

Jean Jules Fifen1, Mama Nsangou, Zoubeida Dhaouadi

  • 1Department of Physics, Faculty of Science, University of Ngaoundere, P.O. Box 454, Ngaoundere, Cameroon. julesfifen@gmail.com

The Journal of Chemical Physics
|May 17, 2013
PubMed
Summary

Determining proton solvation energies and pKa values requires understanding methanol cluster structures. Temperature and solvent effects influence cluster stability, with temperature dominating small clusters and solvent effects dominating larger ones.

More Related Videos

Spatial Separation of Molecular Conformers and Clusters
10:37

Spatial Separation of Molecular Conformers and Clusters

Published on: January 9, 2014

High-Temperature and High-Pressure In situ Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy
08:55

High-Temperature and High-Pressure In situ Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy

Published on: October 9, 2020

Related Experiment Videos

Last Updated: May 11, 2026

Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry
12:11

Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry

Published on: April 8, 2020

Spatial Separation of Molecular Conformers and Clusters
10:37

Spatial Separation of Molecular Conformers and Clusters

Published on: January 9, 2014

High-Temperature and High-Pressure In situ Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy
08:55

High-Temperature and High-Pressure In situ Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy

Published on: October 9, 2020

Area of Science:

  • Computational chemistry
  • Physical chemistry
  • Chemical thermodynamics

Background:

  • Accurate pKa and proton solvation energy evaluation is crucial for understanding chemical properties, particularly drug behavior.
  • Protonated methanol clusters ((H+)(MeOH)n) and neutral methanol clusters ((MeOH)n) play a key role in determining these properties in methanol.
  • Understanding the favored structures of these clusters in gas and solution phases at varying temperatures is essential.

Purpose of the Study:

  • To determine the most favored structures of protonated methanol clusters in the gas phase and in methanol solution.
  • To investigate the influence of temperature on the relative populations of different cluster isomers.
  • To elucidate the interplay between temperature and solvent effects on cluster stability.

Main Methods:

  • Geometry optimizations and frequency calculations using M062X/6-31++G(d,p) and B3LYP/6-31++G(d,p) levels of theory.
  • Inclusion of thermal effects using a custom FORTRAN code to analyze temperature-dependent populations.
  • Simulation of cluster behavior across a temperature range of 0 to 400 K.

Main Results:

  • In the gas phase, linear protonated methanol clusters are favored by entropy at high temperatures, while compact structures are favored by energy at low temperatures.
  • In methanol solution, linear structures dominate for n ≤ 6 at high temperatures, with cyclic structures becoming dominant for larger clusters.
  • Compact structures generally dominate at lower temperatures, but their relative order differs between gas and solution phases.

Conclusions:

  • Temperature effects are more significant than solvent effects for small protonated methanol clusters (n ≤ 6).
  • Solvent effects become more dominant than temperature effects for larger protonated methanol cluster sizes (n > 6).
  • The study provides insights into the structural preferences of protonated methanol clusters, crucial for accurate pKa and solvation energy calculations.