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Chiroptical Properties of Twisted Acenes: Experimental and Computational Study
1Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, Israel.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|January 8, 2019
Summary
Twisted acenes exhibit significant chiroptical properties. Computational and experimental studies show that increasing the twist angle enhances rotational strength, making these molecules excellent for chiroptical applications.
Area of Science:
- Organic Chemistry
- Spectroscopy
- Materials Science
Background:
- Acenes are polycyclic aromatic hydrocarbons with potential chiroptical properties when twisted out of planarity.
- Previous research has not explored the impact of twisting on acene chiroptical properties computationally or experimentally.
Purpose of the Study:
- To computationally investigate the chiroptical properties of twisted acenes (anthracenes to pentacenes).
- To experimentally study the chiroptical response of enantiopure, helically locked acenes with varying torsional angles.
Main Methods:
- Computational modeling of acene chiroptical properties.
- Synthesis and circular dichroism spectroscopy of enantiopure twisted acenes.
Main Results:
- The lowest energy transition in acenes becomes dominant in circular dichroism spectra upon twisting.
- Rotational strength of acenes increases with increasing twist angle.
- Experimental data confirms the trend observed in calculations, showing a strong Cotton effect and anisotropy factor.
Conclusions:
- Twisting acenes significantly enhances their chiroptical properties.
- Enantiopure twisted acenes demonstrate strong chiroptical responses, indicating their potential as advanced chiroptical materials.
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