Related Experiment Video
Updated: Apr 26, 2026
10:52
Line Shape Analysis of Dynamic NMR Spectra for Characterizing Coordination Sphere Rearrangements at a Chiral Rhenium Polyhydride Complex
Published on: July 27, 2022
2.8K
Spectroscopic tracking of Schiff base compounds' hydrogen bonding reorganization associated with solid-to-solid phase
Satomi Hara1, Hirohiko Houjou, Isao Yoshikawa
1Institute of Industrial Science, The University of Tokyo , 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan.
The Journal of Physical Chemistry. A
|July 30, 2014
Summary
This study reveals that spectral changes in 2,6-dihydroxynaphthalene derivatives are driven by intermolecular proton transfer and hydrogen bonding, not intramolecular transfer. These interactions influence crystal polymorphs and phase transitions.
Area of Science:
- Materials Science
- Spectroscopy
- Organic Chemistry
Background:
- 2,6-dihydroxynaphthalene derivatives are known for their interesting optical properties.
- Understanding molecular interactions in solid-state is crucial for materials design.
Purpose of the Study:
- To investigate the spectroscopic properties of 2,6-dihydroxynaphthalene-1-methylidene alkylamines.
- To elucidate the mechanism behind observed spectral changes in crystalline samples.
- To correlate spectral changes with intermolecular interactions and phase transitions.
Main Methods:
- Transmission ultraviolet-visible absorption microspectroscopy was employed.
- Solid thin-films of crystalline samples were analyzed.
- Spectral changes were monitored during heating and in response to varying alkyl chain lengths.
Main Results:
- Distinct spectral profiles were observed, dependent on polymorphs and alkyl chain length (C9-C12).
- Spectral changes were attributed to intermolecular proton transfer, not intramolecular.
- Heating induced dramatic spectral shifts preceding solid-to-solid phase transitions.
Conclusions:
- Intermolecular proton transfer and hydrogen bonding significantly influence the optical properties of these compounds.
- Changes in hydrogen bonding networks are key drivers of spectral alterations and phase transitions.
- The findings provide insights into solid-state molecular interactions and their impact on material properties.
More Related Videos
Related Concept Videos
01:23IR Spectrum Peak Broadening: Hydrogen Bonding
1.9K
The vibrational frequency of a bond is directly proportional to its bond strength. As a result, stronger bonds vibrate at higher frequencies, while weaker bonds vibrate at lower frequencies. The stretching vibration of the strong O–H bond in alcohols and phenols (very dilute solution or gas phase) appears as a sharp peak at 3600–3650 cm−1.
However, the extent of hydrogen bonding influences the observed stretching frequency and band broadening. Intermolecular or intramolecular...
However, the extent of hydrogen bonding influences the observed stretching frequency and band broadening. Intermolecular or intramolecular...
1.9K
01:192D NMR: Heteronuclear Single-Quantum Correlation Spectroscopy (HSQC)
1.3K
Heteronuclear single-quantum correlation spectroscopy (HSQC) is a 2D NMR technique that reveals one-bond correlations between hydrogen and a heteronucleus. The HSQC experiment is similar to the heteronuclear correlation experiment (HETCOR) but is more sensitive. In the HSQC spectrum, the proton chemical shift is plotted on the horizontal F2 axis, while the 13C chemical shift is plotted on the vertical F1 axis. The corresponding proton and 13C spectra are also shown. The HSQC contour plot does...
1.3K
01:16UV–Vis Spectroscopy: Molecular Electronic Transitions
3.0K
In Ultraviolet–Visible (UV–Vis) spectroscopy, the absorption of electromagnetic radiation is used to probe the electronic structure of molecules. This technique provides insights into molecular electronic transitions, particularly the movement of electrons between different molecular orbitals. Radiation is absorbed if the energy of the electromagnetic radiation passing through the molecule is precisely equal to the energy difference between the excited and ground states. During this...
3.0K
02:39Phase Transitions: Melting and Freezing
11.6K
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
11.6K
00:52¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
991
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...
991
01:02¹H NMR: Interpreting Distorted and Overlapping Signals
1.3K
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
1.3K