Stacked Reticular Frame Boosted Circularly Polarized Luminescence of Chiral Covalent Organic Frameworks

Cong Du; Xuefeng Zhu; Chenchen Yang; Minghua Liu

doi:10.1002/anie.202113979

Stacked Reticular Frame Boosted Circularly Polarized Luminescence of Chiral Covalent Organic Frameworks

Angew Chem Int Ed Engl. 2022 Jul 11;61(28):e202113979. doi: 10.1002/anie.202113979. Epub 2021 Nov 9.

Authors

Cong Du¹, Xuefeng Zhu¹, Chenchen Yang^{1

2}, Minghua Liu^{1

2}

Affiliations

¹ Beijing National Laboratory for Molecular Science (BNLMS), Key Laboratory of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, ZhongGuanCun North First Street 2, Beijing, 100190, China.
² University of Chinese Academy of Sciences, Beijing, 100049, China.

PMID: 34693602
DOI: 10.1002/anie.202113979

Abstract

Chiral covalent organic frameworks (COFs) with circularly polarized luminescence (CPL) are intriguing as advanced chiroptical materials but have not been reported to date. We constructed chiroptical COF materials with CPL activity through the convenient Knoevenagel condensation of formyl-functionalized axially chiral linkers and C3-symmetric 1,3,5-benzenetriacetonitrile. Remarkably, the as-prepared chiral COFs showed high absorption and luminescent dissymmetric factors up to 0.02 (g_abs ) and 0.04 (g_lum ), respectively. In contrast, the branched chiral polymers from the same starting monomers were CPL silent. Structural and spectral characterization revealed that the reticular frame was indispensable for CPL generation via confined chirality transfer. Moreover, reticular stacking boosted the CPL performance significantly due to the interlayer restriction of frame. This work demonstrates the first example of a CPL-active COF and provides insight into CPL generation through covalent reticular chemistry, which will play a constructive role in the future design of high-performance CPL materials.

Keywords: chiral polymers; chiral reticular materials; circularly polarized luminescence; covalent organic frameworks; stacking-induced emission enhancement.

Abstract

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