Hysteretic Tricolor Electrochromic Systems Based on the Dynamic Redox Properties of Unsymmetrically Substituted Dihydrophenanthrenes and Biphenyl-2,2'-Diyl Dications: Efficient Precursor Synthesis by a Flow Microreactor Method

• Published in: Materials Vol. 4; no. 11; pp. 1906 - 1926
• Main Authors: Ishigaki, Yusuke, Suzuki, Takanori, Nishida, Jun-Ichi, Nagaki, Aiichiro, Takabayashi, Naofumi, Kawai, Hidetoshi, Fujiwara, Kenshu, Yoshida, Jun-Ichi
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.11.2011; MDPI
• Subjects: cationic dye; dynamic redox system; electrochromism; flow microreactor; hysteresis; organic dye; Oxidation; reaction integration; Japan; electrochromism; dynamic redox system; reaction integration; flow microreactor; organic dye; cationic dye; hysteresis
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma4111906

A series of biphenyl-2,2'-diylbis(diarylmethanol)s 3, which have two kinds of aryl groups at the bay region, were efficiently obtained by integrated flow microreactor synthesis. The diols 3NO/NX are the precursors of unsymmetric biphenylic dications 2NO/NX , which are transformed into the corresponding dihydrophenanthrenes 1NO/NX via 2NO/NX upon reduction, when they exhibit two-stage color changes. On the other hand, the steady-state concentration of the intermediate 2NO/NX is negligible during the oxidation of 1NO/NX to 2NO/NX , which reflects unique tricolor electrochromicity with a hysteretic pattern of color change [color 1→color 2→color 3→color 1].