Primary coloured electrochromism of aromatic diesters and phenylenediamines

Abstract

Thirteen aromatic oxygen and thioic S,S'-diesters were synthesized and investigated using electrochemical (cyclic voltammetry and controlled potential electrolysis) and UV-vis spectroscopic techniques over a range of temperatures. Ten of the compounds exhibited vibrant colour changes from a colourless state in their neutral forms to brightly coloured upon one-electron electrochemical reduction in acetonitrile. Several compounds were found to display either red, green or blue colours in their one-electron reduced states.1 The search for better stability electrochromes was extended to the phenylenediamines. Ten easily accessible 1,4-phenylenediamines were studied in detail using electrochemical techniques (voltammetry and controlled potential electrolysis) and UV-vis spectroscopy under ambient conditions. All compounds demonstrated vibrant colour changes upon a one-electron electrochemical oxidation in acetonitrile, with most displaying a primary colour (red, green, blue, or yellow) in their oxidized state.2 The phenylenediamines exhibited excellent stability under ambient temperature without the need for exclusion of atmospheric gases or moisture. The generation of these primary colours can potentially be useful in electronic devices that require colour changes such as display screens and electric windows.