Synthesis and evaluation of 9-substituted anthracenes with potential in reversible polymer systems

A large series of functional 9-substituted anthracenes was synthesized and evaluated for the ability to undergo [4+4]-cycloadditions, forming dimers upon irradiation with UVA, and for their dimers to dissociate thermally. This scission of the dimers was shown to proceed in a clean and efficient way at temperatures between 90 degrees C and 200 degrees C. It was shown that the dissociation temperature is significantly influenced by the substituent. The Arrhenius parameters of the scission reactions were determined by fluorescence spectroscopy and correlated to the type of substituent. The absorption and emission maxima of the prepared monomeric anthracenes red-shift with increasing electron-donating power of the 9-substituent. Those results will be applied in a forthcoming study addressing tailor-made reversible polymer systems. (C) 2016 Elsevier Ltd. All rights reserved.