Photochromic dihetarylethenes 4.~* The molecular and crystal structures of 1,2-bis(2-ethyl-5-ethylsulfonylthien-3-yl)perfluorocyclopentene and 1,2-bis[5-(benzoxazol-2-yl)-2-methylthien-3-yl]perfluorocyclopentene

摘要

The structures of two hetarylethene photochromes, viz., 1,2-bis(2-ethyl-5-ethylsulfonylthien-3-yl)perfluorocyclopentene and 1,2-bis[5-(benzoxazol-2-yl)-2-methylthien-3-yl]perfluorocyclopentene, were established by X-ray diffraction analysis. The conformational parameters of thetitle compounds are considered. The cyclopentene ring in the former compound is planar and this ring in the latter compound adopts an evelope conformation. There are no overall conjugated systems in the molecules under study. In both strutuctures, the dihetaryl fragments are rotated with respect to the perfluorocyclopentene fragments by ～55deg. The thiophene and benzoxazole rings in 1,2-bis[5-(benzoxazol-2-yl)-2-methylthien-3-yl]perfluorocyclopentene are coplanar.