Light-Powered Atroposelective Ratcheting via Excited-State Donor-Acceptor Interactions
Chun-Wei Chiu1, Hsiu-Feng Lu2, Sudhakar Narra3
1Department of Chemistry, National Taiwan University, Taipei, Taiwan.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|July 8, 2026
Summary
This study introduces a light-powered system that selectively converts molecular isomers using a pentiptycene scaffold. This photochemical control enables the accumulation of specific atropisomers, paving the way for light-driven molecular machines.
Area of Science:
- Photochemistry
- Supramolecular Chemistry
- Molecular Machines
Background:
- Controlling molecular motion with light is crucial for developing advanced materials.
- Achieving selectivity in photochemical reactions, especially with rapidly equilibrating isomers, remains a challenge.
Purpose of the Study:
- To develop a light-powered system for atroposelective isomerization.
- To investigate the mechanism of photochemical control using a desymmetrized pentiptycene scaffold.
- To explore the potential for constructing light-driven rotary molecular motors (LRMMs).
Main Methods:
- Synthesis of a desymmetrized pentiptycene scaffold.
- Photochemical irradiation studies.
- Ultrafast transient spectroscopy.
- Theoretical calculations (e.g., DFT).
Main Results:
- Demonstrated a light-powered atroposelective ratcheting system based on the pentiptycene scaffold.
- Achieved selective Z → E photoisomerization, suppressing one atropisomer's consumption and leading to its accumulation.
- Identified electronic interactions in the excited state as the origin of photochemical atroposelectivity.
Conclusions:
- The pentiptycene framework enables precise photochemical control over molecular motion.
- This system serves as a potential precursor for light-driven rotary molecular motors.
- Conformer-dependent photochemistry is key to achieving selective molecular transformations.
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