Achieving Multiple Room-Temperature Phosphorescence and Circularly Polarized Luminescence from Donor-Acceptor Decorated BINAPO Emitters

Abstract

Recently, circularly polarized luminescence (CPL) and room-temperature phosphorescence (RTP) materials have attracted significant attention across various fields. The stereogenic biaryl units are critical sources of CPL and RTP activity, including binaphthyl, binaphthalenediol, and binaphthalenediamine derivatives. However, the stereoselective transformation and chiroptical functionalization of 1,1′-binaphthyl-2,2′-diphemyl phosphine (BINAP) and its oxide (BINAPO) are largely unexplored. Herein, a series of axially chiral luminous molecules is prepared by modular covalent-linking of BINAP/BINAPO and arylamine donors (N-phenylcarbazole (CZ) or triphenylamine (TPA)) at 4,4′-positions to study their photoluminescence and chiroptical properties. Intriguingly, the molecules based on BINAPO emit intense fluorescence, and the persistent RTP of 301−578 ms is achieved when these compounds are doped in the polymer matrixes, which contributes to the formation of the optimized energy gap and intersystem crossing (ISC) by virtue of intramolecular charge transfer (ICT) states and heavier phosphorus atoms. Circular dichroism (CD) spectral studies reveal that all BINAP/ BINAPO derivatives exhibit decent optical activity in dichloromethane (DCM) and weak CPL due to the inferior electro-magnetic transition environment. On the contrary, the co-aggregates, consisting of chiral BINAPO derivatives with helical structures and commercial nematic liquid crystals (N-LCs, 5CB), show significantly enhanced CD and CPL signals with the improved FM value of 0.05−0.10.

Keywords

Circularly polarized luminescence / Room-temperature phosphorescence / Phosphine derivatives / Luminescent liquid crystals / Chiral amplification / Donor-acceptor systems / Fluorescence / Doping

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2025 SIOC, CAS, Shanghai, & WILEY-VCH GmbH