Tetrathienyl Corannulene Compounds with Highly Sensitive Photochromism |
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Authors: | Dr Mihoko Yamada Tomoya Sawazaki Mae Fujita Fumio Asanoma Yoshiko Nishikawa Prof Tsuyoshi Kawai |
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Institution: | Division of Materials Science, Nara Institute of Science and Technology, NAIST, Ikoma, Nara, 630-0192 Japan |
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Abstract: | We have designed and synthesized photochromic tetrathienyl corannulene compounds, 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 ), by fusing two units of photochromic terarylene with a curved aromatic corannulene with a promising antenna effect. Compound 1 exhibited highly sensitive photoreactivity, with a large molar absorption coefficient of 8.2×104 M−1 cm−1 and practically photon-quantitative photocyclization. On the other hand, a terarylene derivative with a planar aromatic phenanthrene, 9,10-bis(2,4-dimethyl-5-phenylthiophen-3-yl)phenanthrene ( 4 ) showed no photoreactivity. The reason for such a difference was attributed to the predominance of the photoreactive atropisomers amplified by energy migration, and the shortened distance between reactive carbons induced by the curved structure. |
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Keywords: | atropisomerism corannulenes energy migration photochromism strained molecules |
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