The emergence of aggregation-induced emission luminogens (AIEgens) has significantly stimulated the development of luminescent supramolecular materials because their strong emissions in the aggregated state have resolved the notorious obstacle of the aggregation-caused quenching (ACQ) effect, thereby enabling AIEgen-based supramolecular materials to have a promising prospect in the fields of luminescent materials, sensors, bioimaging, drug delivery, and theranostics. Moreover, in contrast to conventional fluorescent molecules, the configuration of AIEgens is highly twisted in space. Investigating AIEgens and the corresponding supramolecular materials provides fundamental insights into the self-assembly of nonplanar molecules, drastically expands the building blocks of supramolecular materials, and pushes forward the frontiers of supramolecular chemistry. In this review, we will summarize the basic concepts, seminal studies, recent trends, and perspectives in the construction and applications of AIEgen-based supramolecular materials with the hope to inspire more interest and additional ideas from researchers and further advance the development of supramolecular chemistry.

Supramolecular materials based on AIE luminogens (AIEgens): construction and applications

The research in circularly polarized luminescence has attracted wide interest in recent years. Efforts on one side are directed toward the development of chiral materials with both high luminescence efficiency and dissymmetry factors, and on the other side, are focused on the exploitations of these materials in optoelectronic applications. This review summarizes the recent frontiers (mostly within five years) in the research in circularly polarized luminescence, including the development of chiral emissive materials based on organic small molecules, compounds with aggregation-induced emissions, supramolecular assemblies, liquid crystals and liquids, polymers, metal-ligand coordination complexes and assemblies, metal clusters, inorganic nanomaterials, and photon upconversion systems. In addition, recent applications of related materials in organic light-emitting devices, circularly polarized light detectors, and organic lasers and displays are also discussed.

Frontiers in circularly polarized luminescence: molecular design, self-assembly, nanomaterials, and applications

Light-harvesting is one of the key steps in photosynthesis, but developing artificial light-harvesting systems (LHSs) with high energy transfer efficiencies has been a challenging task. Here we report fluorescent hexagonal Pt(II) metallacycles as a new platform to fabricate artificial LHSs. The metallacycles (4 and 5) are easily accessible by coordination-driven self-assembly of a triphenylamine-based ditopic ligand 1 with di-platinum acceptors 2 and 3, respectively. They possess good fluorescence properties both in solution and in the solid state. Notably, the metallacycles show aggregation-induced emission enhancement (AIEE) characteristics in a DMSO–H2O solvent system. In the presence of the fluorescent dye Eosin Y (ESY), the emission intensities of the metallacycles decrease but the emission intensity of ESY increases. The absorption spectrum of ESY and the emission spectra of the metallacycles show a considerable overlap, suggesting the possibility of energy transfer from the metallacycles to ESY, wi...

Self-Assembled Fluorescent Pt(II) Metallacycles as Artificial Light-Harvesting Systems.

Light-harvesting systems are an important way for capturing, transferring and utilizing light energy. It remains a key challenge to develop highly efficient artificial light-harvesting systems. Herein, we report a supramolecular co-assembly based on lower-rim dodecyl-modified sulfonatocalix[4]arene (SC4AD) and naphthyl-1,8-diphenyl pyridinium derivative (NPS) as a light-harvesting platform. NPS as a donor shows significant aggregation induced emission enhancement (AIEE) after assembling with SC4AD. Upon introduction of Nile blue (NiB) as an acceptor into the NPS-SC4AD co-assembly, the light-harvesting system becomes near-infrared (NIR) emissive (675 nm). Importantly, the NIR emitting NPS-SC4AD-NiB system exhibits an ultrahigh antenna effect (33.1) at a high donor/acceptor ratio (250:1). By co-staining PC-3 cells with a Golgi staining reagent, NBD C6 -ceramide, NIR imaging in the Golgi apparatus has been demonstrated using these NIR emissive nanoparticles.

An Efficient Near-Infrared Emissive Artificial Supramolecular Light-Harvesting System for Imaging in the Golgi Apparatus.

Cucurbit[n]urils (Q[n]s or CB[n]s), as a classical of artificial organic macrocyclic hosts, were found to have excellent advantages in the fabricating of tunable and smart organic luminescent materials in aqueous media and the solid state with high emitting efficiency under the rigid pumpkin-shaped structure-derived macrocyclic-confinement effect in recent years. This review aims to give a systematically up-to-date overview of the Q[n]-based supramolecular organic luminescent emissions from the confined spaces triggered host-guest complexes, including the assembly fashions and the mechanisms of the macrocycle-based luminescent complexes, as well as their applications. Finally, challenges and outlook are provided. Since this class of Q[n]-based supramolecular organic luminescent emissions, which have essentially derived from the cavity-dependent confinement effect and the resulting assembly fashions, emerged only a few years ago, we hope this review will provide valuable information for the further development of macrocycle-based light-emitting materials and other related research fields.

Assembly and Applications of Macrocyclic-Confinement-Derived Supramolecular Organic Luminescent Emissions from Cucurbiturils.

Here we report one-pot synthesis of tetraphenylethene-based tetracationic dicyclophane (1) and its self-assembly behaviors with aggregation-induced emission (AIE) and light-harvesting function. Confirmed by X-ray crystal structure and high resolution transmission electron microscopy, this tetracationic dicyclophane can self-assemble into a 3D supramolecular framework to form crystalline nanospheres (2) finally, which exhibits a strong emission (ΦF = 97.7%) via AIE effect in aqueous solution. Interestingly, AIE-active 2 as a single-molecule-based fluorescent supramolecular platform can encapsulate an organic dye (e.g., Nile red) to form light-harvesting nanospheres (3) further with a large red-shift (Δλ = ∼70 nm), highly efficient energy-transfer ability (ΦET = 77.5%), and high antenna effect (14.3).

Aggregation-Induced Emission and Light-Harvesting Function of Tetraphenylethene-Based Tetracationic Dicyclophane

Chiral framework materials have been developed for many applications including chiral recognition, chiral separation, asymmetric catalysis, and chiroptical materials. Herein, we report that an achiral cucurbit[8]uril-based supramolecular organic framework (SOF-1) with the dynamic rotational conformation of tetraphenylethene units can exhibit adaptive chirality to produce M-SOF-1 or P-SOF-1 with mirror-image circular dichroism (CD) with gabs ≈±10-4 and circularly polarized luminescence (CPL) with glum ≈±10-4 induced by L-/D-phenylalanine in water, respectively. The chirality induction in CD (gabs ≈-10-4 ) and CPL (glum ≈-10-4 ) of P-SOF-1 from achiral SOF-1 can be presented by using a small amount of adenosine-5'-triphosphate disodium (ATP) or adenosine-5'-diphosphate disodium (ADP) (only 0.4 equiv) in water. Furthermore, the adaptive chirality of SOF-1 can be used to determine dipeptide sequences (e.g., Phe-Ala and Ala-Phe) and distinguish polypeptides/proteins (e.g., somatostatin and human insulin) with characteristic CD spectra. Therefore, achiral SOF-1 as an ideal chiroptical platform with adaptive chirality may be applied to determine the enantiopurity of amino acids (e.g., L-/D-phenylalanine), develop aqueous CPL materials, and distinguish biological chiral macromolecules (e.g., peptides/proteins) via chirality induction in water.

Adaptive Chirality of an Achiral Cucurbit[8]uril-Based Supramolecular Organic Framework for Chirality Induction in Water.

Supramolecular Organic Frameworks with Controllable Shape and Aggregation‐Induced Emission for Tunable Luminescent Materials through Aqueous Host–Guest Complexation

Aggregation-induced emission and self-assembly of functional tetraphenylethene-based tetracationic dicyclophanes for selective detection of ATP in water

Chunyan Qin

Papers

Aggregation-Induced Emission and Light-Harvesting Function of Tetraphenylethene-Based Tetracationic Dicyclophane

Adaptive Chirality of an Achiral Cucurbit[8]uril-Based Supramolecular Organic Framework for Chirality Induction in Water.

Supramolecular Organic Frameworks with Controllable Shape and Aggregation‐Induced Emission for Tunable Luminescent Materials through Aqueous Host–Guest Complexation

Aggregation-induced emission and self-assembly of functional tetraphenylethene-based tetracationic dicyclophanes for selective detection of ATP in water