Photochromism of 1,2-Bis(2-alkyl-1-benzofuran-3-yl)perfluorocyclopentene Derivatives

✍ Scribed by Tadatsugu Yamaguchi; Masahiro Irie

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 180 KB
• Volume: 2006
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/ejoc.200600011

✦ Synopsis

Abstract

1,2‐Bis(2‐n‐alkyl‐1‐benzofuran‐3‐yl)perfluorocyclopentenederivatives have been synthesized and their photochromic performance has been studied in solution as well as in the single‐crystalline phase. All derivatives undergo photochromism in hexane solution. The introduction of long alkyl chains at the 2‐positions of the benzofuran rings of the bis(1‐benzofuran‐3‐yl)ethenes enhances the cyclization quantum yield. This is attributed to the increase in the population of the antiparallel conformers. The derivatives with methyl, propyl, butyl, pentyl, and hexyl substituents exhibit photochromism even in the single‐crystalline phase. An X‐ray crystallographic analysis reveals that the ethyl‐substituted derivative is packed in a parallel conformation, while the other derivatives are in an antiparallel conformation. This conformational difference controls the reactivity in the crystalline phase. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)