Ion−π interactions for constructing organic luminescent materials

Abstract

Organic luminescent materials are one of the research hotspots worldwide. The luminescent efficiency of these materials can be tuned by introducing noncovalent interactions. Ion−π interactions, mainly including anion−π interactions and cation−π interactions, are relatively new but powerful noncovalent interactions with extensive applications in supramolecular chemistry. The use of ion−π interactions to fabricate highly luminescent materials is initiated since they were introduced to develop aggregation-induced emission luminogens in 2017. Then, this research field is undergoing through challenging but very prospective developments. In this minireview, we start with a brief introduction of ion−π interactions and then make a summary of the reports on organic fluorescence based on ion−π interactions and room temperature phosphorescence induced by ion−π interactions. The applications of organic luminescent materials based on ion−π interactions in bioimaging, imaging-guided anticancer and antibacterial treatment are also discussed. The challenges and prospects of using anion−π and cation−π interactions for constructing organic luminogens are presented in the final part. It is expected that this minireview will provide some guidelines for fabricating novel organic luminescent materials and further extend the application potential of ion−π interactions.

Solvatochromic Near-Infrared Aggregation-Induced Emission-Active Acrylonitriles by Acceptor Modulation for Low-Power Stimulated Emission Depletion Nanoscopy

“…Aggregation-induced emission (AIE)-based fluorophores demonstrate promise in this regard. Since Tang and co-workers proposed the AIE concept in 2001, AIE luminogens (AIEgens) have recently gained considerable attention in diverse biological applications because of their strong emissions in the aggregate state, significant Stokes shifts, and excellent photostability. − Interesting results have been obtained by using distinct AIEgens for super-resolution imaging, including STED imaging. − For instance, Fu and co-workers reported two photostable red AIEgens (PIZ-CN and PID-CN, respectively) with tunable organelle specificity for the STED imaging of dynamic lysosomal fusion and mitochondrial fission with a high resolution of 65.6 nm using a 660 nm STED beam at 1.82 MW/cm 2 . Although some impressive progress has been made, critical requirements for high-power STED beams to ensure excellent imaging resolution still exist.…”

Oxidization enhances type I ROS generation of AIE-active zwitterionic photosensitizers for photodynamic killing of drug-resistant bacteria

“…Photodynamic therapy (PDT), that uses external light-activated photosensitizers (PSs) to produce highly oxidizing reactive oxygen species (ROS) to induce cell or microbe death, has recently attracted considerable attention in disease therapeutics owing to its non-invasiveness, limited therapeutic resistance, excellent spatiotemporal selectivity and minimal side effects. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] According to the mechanism and type of ROS generation, there are mainly two types of PSs (type I and type II). [16][17][18][19] To date, most of the reported PSs have come into effect mainly via the highly oxygen-dependent type II pathway, whereas type I PSs with low-oxygen-dependency have rarely been developed because of the lack of a universal structural design strategy, which limits the therapeutic performance of PDT to some extent.…”

Ultralong excimer phosphorescence by the self‐assembly and confinement of terpyridine derivatives in polymeric matrices

“…Unlike inorganic phosphors containing rare, toxic, and expensive elements, [14] organic room temperature phosphorescence (RTP) materials possess inherent merits of outstanding performance with color-tunable properties, eco-friendliness, and mild preparation conditions. [15][16][17][18][19][20] To date, several effective strategies have been successfully developed to access ultralong RTP mainly based on the promotion of intersystem crossing (ISC) and the suppression of the nonradiative decay of triplet excitons, such as crystal engineering, [21][22][23] Haggregation, [24,25] polymerization, [26][27][28][29] host-guest systems, [30][31][32][33] heavy-atom designs, [34,35] formation of aggregates, [1,[36][37][38][39] construction of frameworks, [40,41] and doping in polymeric matrices. [42][43][44] These effective preparation methods have significantly advanced the development of ultralong organic RTP materials and provided them with more opportunities for practical applications.…”