Halogen Bonding: A New Platform for Achieving Multi-Stimuli-Responsive Persistent Phosphorescence

Angew Chem Int Ed Engl. 2022 Mar 21;61(13):e202200236. doi: 10.1002/anie.202200236. Epub 2022 Feb 16.

Abstract

Monotonous luminescence has always been a major factor limiting the application of organic room-temperature phosphorescence (RTP) materials. Enhancing and regulating the intermolecular interactions between the host and guest is an effective strategy to achieve excellent phosphorescence performance. In this study, intermolecular halogen bonding (CN⋅⋅⋅Br) was introduced into the host-guest RTP system. The interaction promoted intersystem crossing and stabilized the triplet excitons, thus helping to achieve strong phosphorescence emission. In addition, the weak intermolecular interaction of halogen bonding is sensitive to external stimuli such as heat, mechanical force, and X-rays. Therefore, the triplet excitons were easily quenched and colorimetric multi-stimuli responsive behaviors were realized, which greatly enriched the luminescence functionality of the RTP materials. This method provides a new platform for the future design of responsive RTP materials based on weak intermolecular interactions between the host and guest molecules.

Keywords: Halogen Bonding; Host-Guest Systems; Multi-Stimuli-Responsive Luminescence; Radioluminescence; Room-Temperature Phosphorescence; Weak Intermolecular Interactions.