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

Yusuke Ishigaki; Takanori Suzuki; Jun-Ichi Nishida; Aiichiro Nagaki; Naofumi Takabayashi; Hidetoshi Kawai; Kenshu Fujiwara; Jun-Ichi Yoshida

doi:10.3390/ma4111906

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

Materials (Basel). 2011 Oct 26;4(11):1906-1926. doi: 10.3390/ma4111906.

Authors

Yusuke Ishigaki¹, Takanori Suzuki², Jun-Ichi Nishida³, Aiichiro Nagaki⁴, Naofumi Takabayashi⁵, Hidetoshi Kawai⁶, Kenshu Fujiwara⁷, Jun-Ichi Yoshida⁸

Affiliations

¹ Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan. y_ishigaki@mail.sci.hokudai.ac.jp.
² Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan. tak@sci.hokudai.ac.jp.
³ Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan. jnishida@echem.titech.ac.jp.
⁴ Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8530, Japan. anagaki@sbchem.kyoto-u.ac.jp.
⁵ Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8530, Japan. tak@mail.sci.hokudai.ac.jp.
⁶ Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan. kawaih@rs.tus.ac.jp.
⁷ Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan. fjwkn@sci.hokudai.ac.jp.
⁸ Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8530, Japan. yoshida@sbchem.kyoto-u.ac.jp.

Abstract

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/NX²⁺, 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/NX²⁺, which reflects unique tricolor electrochromicity with a hysteretic pattern of color change [color 1→color 2→color 3→color 1].

Keywords: cationic dye; dynamic redox system; electrochromism; flow microreactor; hysteresis; organic dye; reaction integration.