Star-shaped thienoviologens for electrochromism and detection of picric acid in aqueous medium

Abstract

Two star-shaped thienoviologens with good redox and emission properties are reported. The results indicate that the increasing number of thiophene rings can strongly weaken the electron-accepting ability and make its first reduction wave shifted to more negative position, accompanying the decrease of the fluorescence quantum yield. The star-shaped thienoviologens were used as electroactive materials to fabricate electrochromic devices, which showed three-colour changes modulated by the different voltages. The star-shaped thienoviologens were used to detect the picric acid (PA) in aqueous medium with good sensitivity and selectivity (Ksv,5a = 1.94 × 105 L/mol; Ksv,5b = 5.38 × 104 L/mol) due to their special molecular architecture and cathodic conjugated scaffold.