Resonance-Enhanced Emission Effects toward Dual-State Emissive Bright Red and Near-Infrared Emitters

Xue Liu; Fei Zhao; Bang Chen; Yifu Huang; Liyan Xu; Enmin Li; Lilin Tan; Hefeng Zhang

doi:10.1002/chem.202300381

Resonance-Enhanced Emission Effects toward Dual-State Emissive Bright Red and Near-Infrared Emitters

Chemistry. 2023 Jun 19;29(34):e202300381. doi: 10.1002/chem.202300381. Epub 2023 May 2.

Authors

Xue Liu¹, Fei Zhao¹, Bang Chen¹, Yifu Huang^{1

2}, Liyan Xu^{3

4

5}, Enmin Li⁴, Lilin Tan², Hefeng Zhang^{1

2}

Affiliations

¹ Department of Chemistry, Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province, College of Chemistry and Chemical Engeering, Shantou University, Shantou, 515063 (China).
² Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering, Shantou, 515063, China.
³ Guangdong Esophageal Cancer Research Institute, Shantou Sub-center, Cancer Research Center, Shantou University Medical College, Shantou, 515041, China.
⁴ Guangdong Provincial Key Laboratory of, Infectious Diseases and Molecular Immunopathology, Institute of Oncologic Pathology, Shantou University Medical College, Shantou, 515041, China.
⁵ The Key Laboratory of Molecular Biology for, High Cancer Incidence Coastal Chaoshan Area, Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou, 515041, China.

PMID: 37005708
DOI: 10.1002/chem.202300381

Abstract

Resonance-enhanced emission (REE) effect was discovered and lead to a novel dye family of hydrostyryl pyridinium derivatives in our recent work. Herein, the REE effect was employed to design a red and near-infrared dual-state emissive fluorophore family of SW-OH-NO₂ derivatives which were easily synthesized by coupling an electron-withdrawing group (W) onto nitro(hydroxyl)styryl (S-OH-NO₂ ) through a C=C double bond as π-bridge. The deprotonation of a phenolic hydroxyl group promoted by a nitro group and the electron-withdrawing group (W) on the other side of the π-bridge triggered resonance, resulting in significantly red-shifted emission. All the resultant SW-OH-NO₂ compounds showed excellent dual-state emission behavior. Remarkably, hydrostyryl quinolinium (SQ-OH-NO₂ ) is one of the smallest NIR emitter molecular skeleton (λ_em =725 nm, MW<400) and showed dual-state emission characteristics and obvious viscosity-depended fluorescent behaviors. In addition to constructing electron donor-acceptor structures and prolonging π-bridges, the REE effect promises a reliable strategy toward novel fluorophores with small size, long emissive wavelength, and dual-emission characteristics, and importantly, feasible industrial manufactures and applications due to their easy and low-cost synthesis strategy.

Keywords: dual-state emission; easy synthesis; low molecular weight; near infrared fluorescence; resonance.

Abstract

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