ChemRxiv
These are preliminary reports that have not been peer-reviewed. They should not be regarded as conclusive, guide clinical practice/health-related behavior, or be reported in news media as established information. For more information, please see our FAQs.
1/1
2 files

Azobispyrazole Family as Photoswitches Combining (Near-)Quantitative Bidirectional Isomerization and Widely Tunable Thermal Half-Lives from Hours to Years

preprint
revised on 03.03.2021, 04:17 and posted on 03.03.2021, 07:48 by Yixin He, Zhichun Shangguan, Zhao-Yang Zhang, Mingchen Xie, Chunyang Yu, Tao LI
Azobenzenes are classical molecular photoswitches that have received widespread application. In recent endeavors of molecular design, replacing one or both phenyl rings by heteroaromatic ones is emerging as a strategy to expand the molecular diversity and to access improved photoswitch properties. However, the currently available heteroaryl azo switches generally show limitations on E Z photoisomerization yields and/or Z-isomer stability. Here we report a family of azobispyrazoles as new photoswitches, which combine (near-)quantitative bidirectional photoconversions and widely tunable Z-isomer thermal half-lives (t1/2) from hours to years. A visible-light-activated photoswitch is also obtained. Systematic experimental and theoretical investigations reveal the different geometric and electronic structures of azobispyrazoles from those of phenylazopyrazoles, overcoming the conflict existing in the latter between effective photoconversion and Z-isomer stability. Our work shows the great potential of azobispyrazoles in developing photoresponsive systems and can inspire the rational design of new photoswitches making use of bis-heteroaryl azo architecture.

History

Email Address of Submitting Author

zy_zhang@sjtu.edu.cn

Institution

Shanghai Jiao Tong University

Country

China

ORCID For Submitting Author

0000-0003-0991-9489

Declaration of Conflict of Interest

The authors declare no competing financial interest.

Exports

ChemRxiv

Exports