One/Two‐Photon‐Excited ESIPT‐Attributed Coordination Polymers with Wide Temperature Range and Color‐Tunable Long Persistent Luminescence

Abstract

The multiple metastable excited states provided by excited‐state intramolecular proton transfer (ESIPT) molecules are beneficial to bring temperature‐dependent and color‐tunable long persistent luminescence (LPL). Meanwhile, ESIPT molecules are intrinsically suitable to be modulated as D‐π‐A structure to obtain both one/two‐photon excitation and LPL emission simultaneously. Herein, we report the rational design of a dynamic CdII coordination polymer (LIFM‐106) from ESIPT ligand to achieve the above goals. By comparing LIFM‐106 with the counterparts, we established a temperature‐regulated competitive relationship between singlet excimer and triplet LPL emission. The optimization of ligand aggregation mode effectively boost the competitiveness of the latter. In result, LIFM‐106 shows outstanding one/two‐photon excited LPL performance with wide temperature range (100–380 K) and tunable color (green to red). The multichannel radiation process was further elucidated by transient absorption and theoretical calculations, benefiting for the application in anti‐counterfeiting systems.

Excited-State Intramolecular Proton Transfer (ESIPT) Based Metal–Organic Supramolecular Optical Materials: Energy Transfer Mechanism and Luminescence Regulation Strategy

“…In addition, the phenyl carbazole group can be used as an intermolecular contact platform to further stabilize the framework structure by providing a variety of supramolecular interactions and inhibit nonradiative energy dissipation. LIFM-106 not only increases the limit temperature of high-power one-photon excited LPL emission to 380 K but also realizes low-power two-photon excited LPL emission at room temperature (Figure c,d) …”

“…(d) The rational ligand modification and J-aggregation in LIFM-106 enhances the competitiveness of monomer LPL to counterbalance the excimer emission, which greatly increases the limit temperature of LPL. (c,d) Reproduced with permission from ref . Copyright 2023 Wiley-VCH.…”

“…To date, according to the types of ESIPT sites, most studied ESIPT ligands to construct metal–organic supramolecular materials can be divided into derivatives of azoles, quinolines, pyrimidines, salicylates, etc. And the general metal ions can include the d 10 -type ions (Zn 2+ , Cd 2+ , In 3+ ), ,,− ,,,,− alkali-earth ions (Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ ), ,,,− Zr 4+ ions, , rare earth ions (Ln 3+ ), ,, etc. Basically, the strategy for the construction of ESIPT metal–organic supramolecular materials must consider the following three principles.…”