A cavitand-based supramolecular artificial light-harvesting system with sequential energy transfer for photocatalysis

Bionic Artificial Leaves Based on AIE-Active Supramolecular Hydrogel for Efficient Photocatalysis

A novel hydrogel-based biomimetic artificial leaf is fabricated by integrating host-guest interactions with covalent bonding. Specifically, a water-soluble tetraphenylethylene-embedded pillar[5]arene (m-TPEWP5), which exhibits aggregation-induced emission (AIE) property, is synthesized as the host molecule. An amphiphilic guest G is introduced to form a stable complex (HGSM) via non-covalent interactions. Subsequent copolymerization of HGSM with gelatin methacryloyl (GelMA) yields a hydrogel network (HGGelMA), which not only exhibits AIE characteristics but also enables encapsulation of the acceptor eosin Y (ESY), thereby resulting in the construction of an artificial light-harvesting system HGGelMA⊃ESY that serves as a biomimetic leaf. To emulate natural photosynthesis more closely and optimize the utilization of the collected energy, two organic reactions are performed within this artificial leaf: dehalogenation of bromoacetophenone derivatives and coupling of benzylamine. These reactions demonstrate remarkable catalytic activity and recycling ability during the photocatalytic process.

Supramolecular artificial light-harvesting systems incorporating aggregation-induced emissive components: from fabrication to efficient energy conversion

The harvesting and utilization of light energy have increasingly captivated researchers. The construction of artificial light harvesting systems (ALHSs) through supramolecular assemblies has emerged as a prominent approach. Following the discovery of the aggregation-induced emission (AIE) phenomenon, AIE luminogens (AIEgens) have been extensively employed to develop ALHSs, in which these molecules are assembled into nanoparticles or nanoaggregates to enhance energy transfer efficiency. In this review, we summarize recent research advances in supramolecular ALHSs based on AIEgens, including some representative examples reported by our research group and others. In particular, different design strategies for ALHSs formed by self-assembly of host-guest complexes and other building blocks such as macrocyclic and amphiphilic molecules have been discussed over the past three years. For host-guest complexes with AIE activity, we analyze the design principles of AIE-active hosts or guests, and how their self-assembly influences the efficiency of ALHSs. For AIE-active macrocycles or amphiphiles that do not form host-guest complexes, we discuss how they can independently self-assemble into ALHSs. Finally, future research directions for the utilization of AIEgens in the development of ALHSs are discussed.

Enhanced emission in a supramolecular artificial light-harvesting system for a photocatalytic thiol-ene reaction

A novel supramolecular artificial light-harvesting system (LHS) was constructed through the host-guest assembly of water-soluble phosphate-pillar[5]arene (WPP5), AIE-enhanced donor (BND), and Eosin Y (ESY) acceptor. This LHS could significantly promote the photocatalytic thiol-ene click reaction of thiophenol and styrene derivatives.

Artificial light harvesting systems based on novel AIEgen-branched rotaxane dendrimers for photocatalyzed functionalization of C-H bonds

Aiming at the construction of novel luminescent materials for practical use, a new type of AIEgen-branched rotaxane dendrimer with up to 42 TPE units precisely distributed with dendrimer skeletons was successfully synthesized. Attributed to such high-density topological arrangements of AIEgens, these novel rotaxane-branched dendrimers revealed interesting generation-dependent AIE behaviors. Moreover, taking advantage of the efficient Förster resonance energy transfer (FRET) process, novel artificial light-harvesting systems (LHSs) were successfully constructed by the employment of ESY as energy acceptors, which revealed significantly enhanced photocatalytic performances in the functionalization of C-H bonds along with an increase in dendrimer generation, thus indicating an impressive generation effect.

Solvent-mediated subcomponent self-assembly of covalent metallacycles for hierarchical porous materials synthesis

We report a solvent-mediated subcomponent self-assembly strategy for synthesizing tetranuclear and triangular covalent metallacycles. The results demonstrate that the polarity of solvent significantly influences the structural outcome of metallacycles, and the square-shaped metallacycles can serve as building blocks for the construction of hierarchical porous materials such as metallacycle-based hydrogen-bonded organic frameworks (mHOFs) and metal-organic frameworks (mMOFs).

The Versatile Applications of Calix[4]resorcinarene-Based Cavitands

The advancement of synthetic host-guest chemistry has played a pivotal role in exploring and quantifying weak non-covalent interactions, unraveling the intricacies of molecular recognition in both chemical and biological systems. Macrocycles, particularly calix[4]resorcinarene-based cavitands, have demonstrated significant utility in receptor design, facilitating the creation of intricately organized architectures. Within the realm of macrocycles, these cavitands stand out as privileged scaffolds owing to their synthetic adaptability, excellent topological structures, and unique recognition properties. So far, extensive investigations have been conducted on various applications of calix[4]resorcinarene-based cavitands. In this review, we will elaborate on their diverse functions, including catalysis, separation and purification, polymeric materials, sensing, battery materials, as well as drug delivery. This review aims to provide a holistic understanding of the multifaceted roles of calix[4]resorcinarene-based cavitands across various applications, shedding light on their contributions to advancing the field of supramolecular chemistry.

Supramolecular light-harvesting systems utilizing tetraphenylethylene chromophores as antennas

Efficient utilization of light energy is crucial for various technological applications ranging from solar energy conversion to optoelectronic devices. Supramolecular light-harvesting systems (LHS) have emerged as promising platforms for enhancing light absorption and energy transfer process. In this Feature Article, we highlight the utilization of tetraphenylethylene (TPE) chromophores as antennas in supramolecular assemblies for light harvesting applications. TPE, as an archetypal aggregation-induced emission (AIE) chromophore, offers unique advantages such as high photostability and efficient light-harvesting capabilities upon self-assembly. We discuss the design principles and synthetic strategies employed to construct supramolecular assemblies incorporating TPE chromophores, elucidating their roles as efficient light-harvesting antennas. Furthermore, we delve into the mechanisms governing energy transfer processes within these assemblies, such as Förster resonance energy transfer (FRET). The potential applications of these TPE-based supramolecular systems in various fields, including photocatalysis, reactive oxygen species generation, optoelectronic devices and sensing, are explored. Finally, we provide insights into future directions and challenges in the development of next-generation supramolecular LHSs utilizing TPE chromophores.

Laponite-activated AIE supramolecular assembly with modulating multicolor luminescence for logic digital encryption and perfluorinated pollutant detection

Recently, the non-covalently activated supramolecular scaffold method has become a prominent research area in the field of intelligent materials. Here, the inorganic clay (LP) promoted the AIE properties of 4,4',4″,4‴-(ethene-1,1,2,2-tetrayltetrakis(benzene-4,1-diyl))tetrakis(1-ethylpyridin-1-ium) (P-TPE), showing an astonishing 42-fold enhancement of the emission intensity of the yellow-green luminescence and a 34-fold increase of the quantum yield via organic-inorganic supramolecular strategy as well as the efficient light-harvesting properties (energy transfer efficiency up to 33 %) after doping with the dye receptor Rhodamine B. Furthermore, the full-color spectral regulation, including white light, was achieved by adjusting the ratio of the donor to the acceptor component and co-assembling with the carbon dots (CD). Interestingly, this TPE-based non-covalently activated full-color supramolecular light-harvesting system (LHS) could be achieved not only in aqueous media but also in the hydrogel and the solid state. More importantly, this panchromatic tunable supramolecular LHS exhibited the multi-mode and quadruple digital logic encryption property as well as the specific detection ability towards the perfluorobutyric acid and the perfluorobutanesulfonic acid, which are harmful to human health in drinking water. This result develops a simple, convenient and effective approach for the intelligent anti-counterfeiting and the pollutant sensing.

Multi-step FRET systems based on discrete supramolecular assemblies

Fluorescence resonance energy transfer (FRET) from the excited state of the donor to the ground state of the acceptor is one of the most important fluorescence mechanisms and has wide applications in light-harvesting systems, light-mediated therapy, bioimaging, optoelectronic devices, and information security fields. The phenomenon of sequential energy transfer in natural photosynthetic systems provides great inspiration for scientists to make full use of light energy. In recent years, discrete supramolecular assemblies (DSAs) have been successively constructed to incorporate donor and multiple acceptors, and to achieve multi-step FRET between them. This perspective describes recent advances in the fabrication and application of DSAs with multi-step FRET. These DSAs are categorized based on the non-covalent scaffolds, such as amphiphilic nanoparticles, host-guest assemblies, metal-coordination scaffolds, and biomolecular scaffolds. This perspective will also outline opportunities and future challenges in this research area.

Carbazole-based artificial light-harvesting system for photocatalytic cross-coupling dehydrogenation reaction

A carbazole-based artificial light-harvesting system (LHS) was successfully fabricated based on the supramolecular assembly of AIE-enhanced donor (CTD), water-soluble phosphate-pillar[5]arene (WPP5), and eosin Y (ESY) acceptor. The formed WPP5-CTD possessed remarkable AIE emission, featuring an ideal energy donor for light harvesting. After encapsulation of ESY, the energy of WPP5-CTD was efficiently transferred to ESY in WPP5-CTD-ESY, and the antenna effect was 38.5, which was much higher than that of recently reported LHSs. Notably, WPP5-CTD-ESY was successfully utilized as a photocatalyst to realize the cross-coupling dehydrogenation reaction of diphenylphosphine oxide and benzothiazole derivatives, suggesting great potential for aqueous photocatalytic applications of this LHS.