N-Substituted Dicyanomethylphenyl Radicals: Dynamic Covalent Properties and Formation of Stimuli-Responsive Cyclophanes by Self-Assembly

Toshiyuki Kobashi; Daisuke Sakamaki; Shu Seki

doi:10.1002/anie.201603409

N-Substituted Dicyanomethylphenyl Radicals: Dynamic Covalent Properties and Formation of Stimuli-Responsive Cyclophanes by Self-Assembly

Angew Chem Int Ed Engl. 2016 Jul 18;55(30):8634-8. doi: 10.1002/anie.201603409. Epub 2016 Jun 3.

Authors

Toshiyuki Kobashi¹, Daisuke Sakamaki², Shu Seki³

Affiliations

¹ Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan.
² Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan. sakamaki@moleng.kyoto-u.ac.jp.
³ Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan. seki@moleng.kyoto-u.ac.jp.

PMID: 27258940
DOI: 10.1002/anie.201603409

Abstract

Dynamic covalent bonds and their chemistry have been of particular interest both from a fundamental and materials science aspect. Demonstrated herein is that triphenylamine (TPA) and carbazole (Cz), substituted with a dicyanomethyl radical, are useful motifs for dynamic covalent chemistry as they have the appropriate bond strength between monomer units as well as high stability and synthetic simplicity. TPA and Cz units substituted by two dicyanomethyl radicals formed macrocyclic oligomers classified as novel types of azacyclophanes, and in particular, the TPA-based diradical gave a cyclic dimer in almost quantitative yield. The cyclic oligomers exhibited thermo- and mechanochromic behavior resulting from the generation of radical species by intermonomer C-C bond cleavage.

Keywords: cyclophanes; radicals; self-assembly; substituent effects; thermochromism.

Publication types

Research Support, Non-U.S. Gov't