An overview on AIEgen‐decorated porphyrins: Current status and applications

Abstract

One of the major obstacles of porphyrins is the aggregation-caused quenching (ACQ) of photoluminescence due to the strong intermolecular π-π interaction of the planar porphyrin core in the solid state. However, ACQ leads to the nonradiative deactivation of the photoexcited states which results in short-lived charge-separated states and thus low photoluminescence and singlet quantum yields. This phenomenon would limit the utilization of porphyrins in near-infrared fluorescent bioimaging, photodynamic therapy, photocatalytic hydrogen evolution, electrochemiluminescence, and chiroptical applications. Hence, to address the ACQ property of porphyrins and enhance the performance of the above applications, a limited number of AIEgen-decorated porphyrins have been designed, synthesized, and tested for their applications. It has been found that the introduction of AIEgens, such as tetraphenylethylene, diphenylacrylonitrile, (3,6-bis-(1-methyl-4-vinylpyridinium)-carbazole diiodide, and iridium motif into the porphyrin core, transformed the porphyrins from ACQ to aggregation-induced emission (AIE) in their solid state due to the reduced strong intermolecular π-π stacking of porphyrins. Consequently, such porphyrins containing AIE features are employed as potential candidates in the above-mentioned applications. In this review, we summarize the AIEgen-decorated porphyrins which have been published to date, and also discuss the benefits of converting porphyrins from ACQ to AIE for enhanced performance within each application. As far as we know, there is no review that summarizes the structures and applications of AIEgen-decorated porphyrins to date. Therefore, we presume that this review would be helpful to design more efficient AIEgen-decorated porphyrins for a wide range of applications in the future.

Design of AIEgen‐based porphyrin for efficient heterogeneous photocatalytic hydrogen evolution

“…Noteworthily, the absorption profile of TPE‐ZnPF is highly red‐shifted and broadened in THF/water (H 2 O) mixture solution compared to that in THF solution, implying the formation of J ‐type aggregates in THF/H 2 O. [ 15 ] In the case of Ph‐ZnPF, the absorption profile is slightly red‐shifted and broadened in THF/H 2 O in comparison to that in THF. Obviously, TPE‐ZnPF aggregates cover a much broader absorption spectrum from 290 to 920 nm than Ph‐ZnPF aggregates.…”

“…[1] However, most porphyrins exhibit aggregation-caused quenching (ACQ) of photoluminescence in the solid state due to the strong π-π stacking of planar porphyrin moieties. [14,15] This tendency activates the nonradiative decay channels which further shorten the electron lifetimes (τ PL ) of photoexcited states and subsequently low photoluminescence quantum yields (Φ PL ) and therefore inferior PHE performance of porphyrin-based photosensitizers.…”

Transformation of Styrene into Biodegradable Polymer through In Situ Epoxidation-Copolymerization Using Tandem Polymeric Catalysts

“…Meanwhile, Al porphyrin was widely studied in the ROCOP of epoxide/cyclic anhydride. The porphyrin complexes featured with large π-conjugated systems , could promote the intramolecular multiple interactions between Mn and Al centers for better catalytic performance. − Collectively, a series of tandem polymeric Mn–Al porphyrin catalysts were designed, as shown in Figure a. Oxidant was also an important part of the ISECOP system.…”

Overcoming Aggregation-Caused Quenching by an Improved Porphyrin Hybrid and Its Application in Enhanced Electrochemiluminescence Biosensing

“…21−23 The poor stability of water-soluble porphyrins and the aggregation-caused quenching (ACQ) effect result in low ECL emission efficiency, which limits their application as emitters in the field of ECL. 24 ACQ is a phenomenon prevalent in conventional fluorescent polymers. Fluorescent substances exhibit high fluorescence at low concentrations and partial or complete bursting at high concentrations or in the aggregated state, which is defined as the ACQ effect.…”

“…On the other hand, the excellent properties of porphyrins in photovoltaics have extended the application of some porphyrin-based materials in photocatalysis, energy transfer, and sensing . In addition, the broad potential, rigid structure, and abundant coordination chemistry have also made them of widespread interest as ECL luminophores. , However, among the few studies reported on the application of porphyrins in ECL systems, most of them are only soluble in organic solvents. − The poor stability of water-soluble porphyrins and the aggregation-caused quenching (ACQ) effect result in low ECL emission efficiency, which limits their application as emitters in the field of ECL . ACQ is a phenomenon prevalent in conventional fluorescent polymers.…”