Syntheses and Photochromic Studies of Dithienylethene-Containing Imidazolium Derivatives and Their Reactivity towards Nucleophiles

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 imidazo hum 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