The allomorphism of a photochromic diarylethene精选.pdfVIP

TETRAHEDRON LETTERS Pergamon Tetrahedron Letters 44 (2003) 1011–1014 The allomorphism of a photochromic diarylethene Shou-Zhi Pu,a Fu-Shi Zhang,a,* Fan Sun,a Ru-Ji Wang,a Xin-Hong Zhoua and Shek-Kiu Chanb aDepartment of Chemistry, Tsinghua University, Beijing 100084, China bFaculty of Science and Technology, University of Macau, Macau 3001, China Received 14 October 2002; revised 21 November 2002; accepted 29 November 2002 Abstract—The photochromic diarylethene, 1,2-bis(2-methyl-5-(2,2-dicyanovinyl)-thien-3-yl)perfluorocyclopentene (1a), was syn- thesized by a novel method. Two kinds of single crystals of the compound were obtained depending on the different recrystallization conditions and their structures were determined by X-ray crystallographic analysis. Allomorphism of the photochromic diarylethene was discovered. The compound underwent a photochromic reaction both in solution and in the single crystalline phase of the anti -parallel conformer. © 2003 Elsevier Science Ltd. All rights reserved. Much attention has been devoted to photochromic any crystalline phase is determined by the crystalliza- compounds because of their potential applicability to tion conditions, such as the recrystallization solvent, optical memories and photonic switching devices.1 concentration, temperature, the velocity