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Direct Imaging of Laser-driven Ultrafast Molecular Rotation
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A Rotation-Inversion Dual-Motion Molecular Switch: Race for NMR Signaling
Zi-Jian Chen1, Hsiu-Feng Lu2, Ito Chao2
1Department of Chemistry, National Taiwan University, Taipei, Taiwan 10617.
The Journal of Organic Chemistry
|March 24, 2022
Summary
Molecular motion detection is achieved by observing NMR signals. The study reveals how thermal helical inversion and dimethylamino group rotation influence these signals in a dual-motion system.
Area of Science:
- Photochemistry
- Molecular Dynamics
- Nuclear Magnetic Resonance (NMR) Spectroscopy
Background:
- Stiff-stilbene derivatives exhibit complex molecular motions.
- Dimethylamino (DMA) group rotation and thermal helical inversion (THI) are key dynamic processes.
- NMR spectroscopy is sensitive to molecular motion.
Purpose of the Study:
- To investigate the interplay between THI and DMA rotation in molecule 1.
- To demonstrate how NMR signals can detect different motion kinetics.
- To explore the concept of switchable motion detection in a dual-motion system.
Main Methods:
- Synthesis and characterization of molecule 1.
- Variable temperature Nuclear Magnetic Resonance (NMR) spectroscopy.
- Photochemical isomerization studies (E to Z).
Main Results:
- The DMA NMR signals in (E)-1 are dependent on THI kinetics.
- The DMA NMR signals in (Z)-1 are dependent on DMA rotation kinetics.
- The faster motion mode dictates the observed NMR signal dependence.
- Photochemical switching between (E)-1 and (Z)-1 alters the motion detection mechanism.
Conclusions:
- NMR signals can selectively detect different molecular motion modes in a dual-motion system.
- The phenomenon of switchable motion detection is demonstrated.
- Understanding molecular dynamics through NMR is crucial for designing responsive molecular systems.
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