Volume 62, Issue 8 e202218023
Research Article

Helical β-isoindigo-Based Chromophores with B−O−B Bridge: Facile Synthesis and Tunable Near-Infrared Circularly Polarized Luminescence

Yongqiang Xu

Yongqiang Xu

College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, and Key Laboratory of Organosilicon Material Technology of Zhejiang Province, Hangzhou Normal University, Hangzhou, 311121 China

These authors contributed equally to this work.

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Dr. Zhigang Ni

Dr. Zhigang Ni

College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, and Key Laboratory of Organosilicon Material Technology of Zhejiang Province, Hangzhou Normal University, Hangzhou, 311121 China

These authors contributed equally to this work.

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Yao Xiao

Yao Xiao

College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, and Key Laboratory of Organosilicon Material Technology of Zhejiang Province, Hangzhou Normal University, Hangzhou, 311121 China

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Ziwei Chen

Ziwei Chen

College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, and Key Laboratory of Organosilicon Material Technology of Zhejiang Province, Hangzhou Normal University, Hangzhou, 311121 China

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Dr. Sisi Wang

Dr. Sisi Wang

College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, and Key Laboratory of Organosilicon Material Technology of Zhejiang Province, Hangzhou Normal University, Hangzhou, 311121 China

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Lizhi Gai

Lizhi Gai

College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, and Key Laboratory of Organosilicon Material Technology of Zhejiang Province, Hangzhou Normal University, Hangzhou, 311121 China

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Prof. Dr. You-Xuan Zheng

Prof. Dr. You-Xuan Zheng

State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023 China

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Prof. Dr. Zhen Shen

Prof. Dr. Zhen Shen

State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023 China

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Prof. Dr. Hua Lu

Corresponding Author

Prof. Dr. Hua Lu

College of Material, Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, and Key Laboratory of Organosilicon Material Technology of Zhejiang Province, Hangzhou Normal University, Hangzhou, 311121 China

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Prof. Dr. Zijian Guo

Prof. Dr. Zijian Guo

State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023 China

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Dedicated to Professor Shigeru Yamago on the occasion of his 60th birthday
First published: 30 December 2022
Citations: 13

Graphical Abstract

A study of a series of helical β-isoindigo-based B−O−B-bridged chromophores has shown that the bridge leads to distorted conformations. This results in the chromophores having excellent spectroscopic and chiroptical properties, such as tunable circularly polarized luminescence (CPL), with a high luminescence dissymmetry factor (glum) of 1.3×10−3 and a CPL brightness (BCPL) of 11.5 M−1 cm−1 in the near-infrared region observed for one of the compounds.

Abstract

It is essential to create organic compounds that exhibit circularly polarized luminescence (CPL) in the near-infrared (NIR) range. Helicene-type emitters possess appealing chiroptical features, however, such NIR molecules are scarce due to a paucity of synthetic strategies. Herein, we developed a series of helical β-isoindigo-based B−O−B bridged aza-BODIPY analogs that were synthesized conveniently. The reaction of diimino-β-isoindigo with a heteroaromatic amine produced a restricted ligand cavity, which triggered off the generation of a B−O−B bridge. The B−O−B bridge led to distorted conformations that satisfy the helical requirements, resulting in excellent spectroscopic and chiroptical properties. Tunable CPL with the highest luminescence dissymmetry factor (glum) of 1.3×10−3 and a CPL brightness (BCPL=11.5 M−1 cm−1) in the NIR region was achieved. This synthetic approach is expected to offer a new opportunity to chiral chemistry and increase flexibility for chiroptical tuning.

Conflict of interest

The authors declare no conflict of interest.

Data Availability Statement

The data that support the findings of this study are available in the supplementary material of this article.

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