Syntheses and photochromic studies of dithienylethene-containing imidazolium derivatives and their reactivity towards nucleophiles

Abstract

A series of dithienylethene-containing imidazolium salts with various substituents on the 2-position of the imidazolium ring has been synthesized. The photochromic properties of these compounds have been studied, and the closed forms are found to be solvatochromic due to the donor-acceptor interaction with the solvent molecules. The closed form of the imidazolium salt shows a much higher affinity towards nucleophiles over the open form of the salt. A reaction pathway has been proposed to account for this reactivity difference based on the structure-property relationship, and the possible structure of the reaction product is discussed. An open-and-shut case: A series of photochromic dithienylethene-containing imidazolium salts has been synthesized. The reactivities of these imidazolium derivatives towards nucleophiles show significant differences between their open and closed forms (see scheme). © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.