Tetrathienyl Corannulene Compounds with Highly Sensitive Photochromism
Mihoko Yamada1, Tomoya Sawazaki1, Mae Fujita1
1Division of Materials Science, Nara Institute of Science and Technology, NAIST, Ikoma, Nara, 630-0192, Japan.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|June 16, 2022
Summary
We synthesized novel photochromic tetrathienyl corannulene compounds. The curved corannulene structure enhances photoreactivity and energy migration, unlike planar analogs.
Area of Science:
- Organic Chemistry
- Materials Science
- Photochemistry
Background:
- Photochromic materials change color upon light exposure.
- Corannulene, a curved polycyclic aromatic hydrocarbon, offers unique structural properties.
- Terarylene units are known for their photochromic behavior.
Purpose of the Study:
- To design and synthesize novel photochromic tetrathienyl corannulene compounds.
- To investigate the influence of corannulene's curved structure on photochromic properties.
- To compare the photoreactivity of curved corannulene derivatives with planar analogs.
Main Methods:
- Synthesis of 1,2,7,8-tetrakis(2-methyl-5-phenylthiophen-3-yl)corannulene (1) and 1,2,7,8-tetrakis(2,4-dimethyl-5-phenylthiophen-3-yl)corannulene (2).
- Characterization of synthesized compounds using spectroscopic techniques.
- Photoreactivity studies comparing compound 1 with a planar phenanthrene derivative (4).
Main Results:
- Compound 1 demonstrated highly sensitive photoreactivity with a large molar absorption coefficient (8.2×10⁴ M⁻¹cm⁻¹).
- Compound 1 exhibited nearly photon-quantitative photocyclization.
- The planar phenanthrene derivative (4) showed no photoreactivity.
- Enhanced photoreactivity in compound 1 is attributed to atropisomer predominance and shortened reactive distances due to the curved corannulene structure, amplified by energy migration.
Conclusions:
- The curved structure of corannulene significantly enhances the photochromic properties of tetrathienyl compounds.
- Energy migration and structural features of curved systems play a crucial role in photoreactivity.
- These findings open avenues for developing advanced photochromic materials based on curved aromatic scaffolds.
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