Electrochemical and electrochromic properties of arylene diimide dyes with N-phenylphenothiazine units. (March 2022)

• Record Type: Journal Article
• Authors: Huang, Yan-Ru; Hsiao, Sheng-Huei
• Is Part Of: Dyes and pigments. Volume 199(2022)
• Publication Date: 2022-03
• Subjects: Phenothiazine -- Aromatic diimides -- Electrochemistry -- Electrochromism; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2021.110056
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: Five arylene diimides containing N -phenylphenothiazine or N -phenyl-3, 7-di- tert -butylphenothiazine units as N -substituents, coded as PTZ-PMDI, PTZ-NTDI, tBuPTZ-PMDI, tBuPTZ-NTDI and tBuPTZ-PTDI, were synthesized from condensation of N -(4-aminophenyl)phenothiazine and N -(4-aminophenyl)-3, 7-di- tert -butylphenothiazine with pyromellitic dianhydride (PMDA ), naphthalene-1, 4, 5, 8-tetracarboxylic dianhydride (NTDA ) and perylene-3, 4, 9, 10-tetracarboxylic dianhydride (PTDA ), respectively. Incorporation of tert -butyl substituents on the PTZ active sites reduces the oxidation potential and increases the redox stability and solubility of the PTZ-diimides. PTZ-PMDI and PTZ-NTDI without tert -butyl substituents on the PTZ units are insoluble in suitable organic solvents, therefore the characterization of their electrochemical and electrochromic properties is unavailable. All the tBuPTZ-diimide compounds were electrochemically active and underwent reversible oxidation and quasi-reversible reduction as evidenced by cyclic voltammetry studies. These diimide compounds changed colors when they were reduced and oxidized, demonstrating their multi-electrochromic properties. The tBuPTZ-diimides gave a colored state of pink and red upon electro-oxidation, together with a low onset bias of 0.6 V and good switching stabilities. The electrochromic devices using these diimides as electroactive compounds were constructed and their electrochromic performance was studied. Graphical abstract: Image 1 Highlights: Redox-active arylene diimide dyes with N -phenylphenothiazine have been synthesized. The diimide dyes showed ambipolar redox and electrochromic properties. The diimides exhibited high optical contrast, coloration efficiency, and cycling stability.