Hexaarylbutadiene: A Versatile Scaffold with Tunable Redox Properties towards Organic Near‐Infrared Electrochromic Material. Issue 7 (10th March 2020)

• Record Type: Journal Article
• Authors: Ishigaki, Yusuke; Harimoto, Takashi; Sugimoto, Keisuke; Wu, Luyan; Zeng, Wenhui; Ye, Deju; Suzuki, Takanori
• Is Part Of: Chemistry, an Asian journal. Volume 15:Issue 7(2020)
• Page Start: 1147
• Page End: 1155
• Publication Date: 2020-03-10
• Subjects: redox chemistry -- cations -- cyclic voltammetry -- absorption; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/asia.201901816
• Languages: English
• ISSNs: 1861-4728

Abstract

Abstract: When the 1, 1, 4, 4‐tetraanilinobutadiene skeleton is attached with two halogenated aryl units at the 2, 3‐positions, they undergo facile two‐electron oxidation to give stable dicationic dyes which exhibit a near‐infrared (NIR) absorption whereas the neutral dienes show only pale color. Therefore, a distinct electrochromic response with an absorption change in the NIR region is achieved, which is attracting considerable recent attention from the viewpoint of bioimaging. Herein, we demonstrate that the redox potentials of the 1, 1, 4, 4‐tetraanilinobutadiene can be precisely controlled by the donating properties of the amino group on the aniline unit as well as the number of halogen atoms on the aryl units at 2, 3‐positions on the butadiene. In contrast, the NIR absorption bands mainly depend on the number of halogen atoms irrespective to the donating properties of aniline unit. Thus, the hexaarylbutadiene skeleton is proven to be a versatile scaffold to develop less‐explored organic NIR electrochromic materials, whose redox and spectroscopic properties can be finely tuned by modifying/attaching the proper substituents. Abstract : Vivid colors : A series of 1, 1, 2, 3, 4, 4‐hexaaryl‐1, 3‐butadienes have been designed as electrochromic material with vivid color change. Under the proper molecular design, these diene‐type electron donors undergo two‐electron oxidation to produce stable dicationic dyes with near‐infrared (NIR) absorption extending to 1000 nm. Redox potentials can be controlled by the donating abilities of the aryl groups while maintaining the NIR absorptions in the oxidized state.