Recent advances in AIEgen‐based crystalline porous materials for chemical sensing

Abstract

Aggregation‐induced emission‐based luminogens (AIEgens) have aroused enormous interest due to their unique high fluorescence in a condensed state. To further explore their potential applications, such as chemical monitoring, immobilization of AIE molecules has been widely studied with a variety of supports. Crystalline porous materials, such as metal‐organic frameworks, covalent organic frameworks, hydrogen‐bonded organic framework, and organic cages, demonstrate well‐controlled structures, large surface areas, and promising stabilities, thus providing a perfect platform for AIE agents loading. Outstanding chemical sensing performances are achieved based on these AIE‐active crystalline porous materials, such as high sensitivity, short response time, selective identification, and high recyclability, which provide a new alternative to readily detect various hazardous molecules. Furthermore, precise structures of AIEgen‐based crystalline porous materials offer an easy way to investigate detection mechanisms. This mini‐review will provide a brief overview of AIEgen‐based crystalline porous materials for detection and then address how to improve sensing performances remarkably.

In Situ Generation of Heterocyclic Polymers by Triple‐Bond Based Polymerizations

“…Most traditional fluorescent polymers suffer from the aggregation-caused quenching effect (ACQ), which greatly limits their application since aggregation formation is a natural process. [50][51][52][53] An opposite effect called aggregationinduced emission (AIE) was firstly reported by our group in 2003, [54] receiving great interest world-wide. The emission of AIE-luminogen is weak in its dissolved state but becomes considerably stronger upon aggregation formation.…”

“…However, traditional fluoresent heterocyclic polymers often suffer from the issue of fluorescence quenching upon the aggregation of polymer chains induced by analytes. [53] AIE-active heterocyclic polymers possess higher fluorescence in aggregate states than that in dilute solutions, which makes them free from the problem of analyte-induced self-quenching. Therefore, AIE-active heterocyclic polymer are desirable candidates as fluorescence chemosensors towards metal ions, explosives, etc.…”

Smart Tetraphenylethene‐Based Luminescent Metal–Organic Frameworks with Amide‐Assisted Thermofluorochromics and Piezofluorochromics

“…[31] Therefore, AIEgens with twisted molecular geometry and molecular rotors shall be superb candidates to design novel luminescent MOFs with smart responsiveness. [22,23,[32][33][34][35][36] Herein, we report an amide-responsive luminescent AIE MOF (ZnETTB) built with elongated AIE ligand, and demonstrate that the incorporation of amide in framework could afford the MOF with excellent thermofluorochromic behavior and largely improved piezofluorochromic sensitivity. In specific, elongation of TPE-derived ligand from 4,4′,4″,4‴-…”

“…[ 31 ] Therefore, AIEgens with twisted molecular geometry and molecular rotors shall be superb candidates to design novel luminescent MOFs with smart responsiveness. [ 22,23,32–36 ]…”

“…[11][12][13][14][15] Transplanting dynamic motifs such as organic ligands with moving moieties (e.g., rotary, vibrational, or elastic elements) into chemically rigid frameworks to derive artificial molecular machinery has been a transformative approach for designing novel smart materials. [16][17][18][19][20][21][22][23][24][25] As compared to conventional luminescent MOFs, the presence of these molecular machinery elements provides attentional and unprecedented responsiveness. Aggregation-induced emission (AIE) fluorogens (AIEgens) are a novel class of organic fluorophores, whose emission is largely associated with their twisted molecular geometry and degree of intramolecular motions.…”