NIR Clusteroluminescence of Non‐conjugated Phenolic Resins Enabled by Through‐Space Interactions

• Published in: Angewandte Chemie International Edition Vol. 62; no. 30; pp. e202306762 - n/a
• Main Authors: Zhang, Ziteng, Zhang, Jianyu, Xiong, Zuping, Chu, Bo, Zhang, Chengjian, Sun, Jing Zhi, Zhang, Haoke, Zhang, Xing‐Hong, Tang, Ben Zhong
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 24.07.2023
• Edition: International ed. in English
• Subjects: Charge transfer; Chemical synthesis; Clusteroluminescence; Conformation; Electron density; Electron transitions; Emission; Emissions; Near infrared radiation; Near-Infrared Luminescence; Phenolic compounds; Phenolic Resin; Phenolic resins; Phenols; Polymers; Resins; Space charge; Theoretical analysis; Through-Space Interactions; Phenolic Resin; Near-Infrared Luminescence; Clusteroluminescence; Through-Space Interactions
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202306762

Clusteroluminescence (CL) and through‐space interactions (TSIs) of non‐conjugated molecules have drawn more attention due to their unique photophysical behaviors that are different from largely conjugated luminogens. However, achieving red and even near‐infrared (NIR) emission from such systems is still challenging due to the intrinsic drawbacks of non‐conjugated molecules and the lack of theories for structure–property relationships. In this work, six phenolic resins are designed and synthesized based on two molecule‐engineering strategies: increasing the number of TSIs units and introducing electron‐donating/‐withdrawing groups. All phenolic resins are verified as luminogens with CL property (CLgens), and the first example of CLgens with NIR emission (maximum emission wavelength ≥680 nm) and high absolute quantum yield (47 %) is reported. Experiments and theoretical analysis reveal that two TSIs types, through‐space locally excited state and through‐space charge transfer state, play essential roles in achieving CL from these non‐conjugated polymers, which could be manipulated via changing structural conformation and electron density or altering electron transition behaviors. This work not only provides an approach to manipulate TSIs and CL of non‐conjugated polymers but also endows commercially available phenolic resins with high practical value as luminescence materials. Nonconjugated luminescent materials derived from well‐developed engineering plastics of phenolic resins could fluoresce from deep blue to the NIR region. This remarkable luminescence is attributed to through‐space interactions (TSIs) and can be manipulated using two molecule‐engineering strategies: increasing the number of TSIs units and introducing D/A groups. The NIR emission endows phenolic resins with practical value as luminescence materials and is a breakthrough in clusteroluminescence from nonconjugated materials.