Multi-Stimuli-Responsive Circularly Polarized Luminescence with Handedness Inversion and Near-Infrared...

Preparing multi-color and multi-stimuli-responsive circularly polarized luminescence (CPL) materials and understanding the evolution of chirality through the visualized mode is still a challenge. Here, an encapsulation engineering approach of chiral metal-organic frameworks (MOFs) is proposed to confine guest emitters to realize multi-color and multi-stimuli-responsive CPL. Based on triplet-triplet energy transfer (TTET), white CPL and near-infrared circularly polarized room temperature phosphorescence (NIR-CPRTP) can be obtained by introducing the pyrene derivatives. With the introduction of the guest containing vinylpyrene group, the light- and thermal-responsive CPL with the signal inversion can be realized through the reversible [2+2] cycloaddition reaction between the ligand and guest triggered by visible light/ultraviolet light or heating. Furthermore, the excitation-dependent CPL is successfully achieved with the incorporation of excited state intramolecular proton transfer (ESIPT) molecules into nanopores. Importantly, the chirality magnification can be greatly enhanced through the chiral spatial confinement, the accurate host-guest single crystal structures of FLT@DCF-12 and FLT@LCF-12 provide the visualized mode to understand the mechanism of chirality transfer, amplification and responsiveness. White LED and multiple information display and encryption are further demonstrated. This breakthrough provides a new perspective to guest-encapsulated chiral MOFs and contributes to the construction of stimuli-responsive CPL-active materials.