Engineering Supramolecular [2]Daisy Chains for Structural Hierarchy-Dependent Emission and Photoreactivity.

Organic photofunctional materials exhibit properties that are highly dependent on their structural hierarchy. The variability in intermolecular interactions and molecular packing in both monomeric and aggregated states complicates the controllability and predictability of their photophysical and photochemical properties. To address this challenge, we developed three luminescent supramolecular [2]daisy chains as simplified models.

Visible Light-Responsive Crystalline B←N Host Adducts with Solvent-Induced Allosteric Effect for Guest Release.

Photo-responsive organic crystals, capable of converting light energy into chemical energy to initiate conformational transitions, present an emerging strategy for developing lightweight and versatile smart materials. However, visible light-triggered tailored guests capture and release behaviors in all-organic solids are rarely reported. Here, we introduce a photoreactive crystalline boron-nitrogen (B←N) host adduct with the ability to undergo [2+2] photocycloaddition upon 447 nm light exposure.

Tandem Solid-Solution Phase Post-Synthetic Modification of Porous Molecular Crystals for In-Situ Generation of Fluorophores.

Conventional synthetic methods of organic luminescent molecules often involve labor-intensive solution-phase organic synthesis, which violate the principles of atom-economic transformation. Post-synthetic modification (PSM) offers a promising alternative, allowing direct transformation from one fluorophore to another. Although PSM is commonly implemented in extended frameworks, its application in porous molecular crystals remains challenging.

A crown ether embedded responsive π-gelator for transition from a one-component gel to a two-component gel.

A novel fluorescent π-gelator, incorporating a crown ether with host-guest recognition capability and a photoactive cyanostilbene unit, was designed. This unique structure enables the successful transition from a one-component gel to a two-component gel and exhibits gel-sol transition behaviors under heat, ions, and light stimuli.

Molecular and Aggregate Synergistic Engineering of Aggregation-Induced Emission Luminogens to Manipulate Optical/Electronic Properties for Efficient and Diversified Functions.

The optical/electronic properties of organic luminescent materials can be regulated by molecular structure modification, which not only requires sophisticated and time-consuming synthesis but also is unable to accurately afford the optical properties of materials in the aggregate state. Herein, a facile strategy of molecular and aggregate synergistic engineering is proposed to manipulate the optical/electronic properties of a luminogen, ACIK, in the solid state for efficient and diversified functions. ACIK is facilely synthesized and exhibits three polymorphic states (ACIK-Y, ACIK-R, and ACIK-N) with a large emission difference of 102 nm from yellow to near-infrared (NIR).

Hierarchical Supramolecular Self-Assembly: Fabrication and Visualization of Multiblock Microstructures.

Due to the fast dynamics and re-equilibration of supramolecular self-assembly, bottom-up molecular strategies to fabricate well-defined and controllable multiblock structures are rare. Herein, we propose a new concept for fabrication of fluorescent multiblock microcolumns containing 1 to 7 blocks via hierarchical supramolecular self-assembly based on cucurbit[8]uril (CB[8]), NaBr and an AIEgen guest. Through the complexation between CB[8] and different numbers of AIEgen guests (2, 1, 0), the competitive displacement caused by the binding of the sodium cation to the CB[8] portal, and the reversible assembly of positively charged guests in salt solutions, one-pot hierarchical supramolecular self-assembly is realized.

Solvent-Triggered Fast and Visible Switching between Cage- and Channel-Type Hydrogen-Bonded Organic Frameworks.

The inherent weak bonding nature of hydrogen-bonded organic frameworks (HOFs) performs like a double-edged sword in that it endows HOFs with superiority in processability and dynamicity but deactivates its on-demand controllability in the crystalline phase. Herein, based on the synergy of dynamic H-bonding interactions and the tailored low solubility in common organic solvents, reversible and fast topological transitions between cage- and channel-type HOFs were achieved upon immersing in the solution state. The aggregation-induced-emission character of the tecton facilitates the visualization of the elusive initial transition process with high sensitivity.

Advances in nanosensors for cardiovascular disease detection.

Cardiovascular diseases (CVDs) are a leading cause of morbidity and mortality around the world. The physiological or pathological processes of CVDs can be well indicated by timely and accurate diagnosis of relevant biomarkers and function parameters. Nanosensors integrating the advantages of nanomaterials and sensing platforms have shown good potential for rapid diagnosis of CVDs, especially for early prediction.

Multiple yet switchable hydrogen-bonded organic frameworks with white-light emission.

The development of new strategies to construct on-demand porous lattice frameworks from simple motifs is desirable. However, mitigating complexity while combing multiplicity and reversibility in the porous architectures is a challenging task. Herein, based on the synergy of dynamic intermolecular interactions and flexible molecular conformation of a simple cyano-modified tetraphenylethylene tecton, eleven kinetic-stable hydrogen-bonded organic frameworks (HOFs) with various shapes and two thermo-stable non-porous structures with rare perpendicular conformation are obtained.

Intra- and Intermolecular Synergistic Engineering of Aggregation-Induced Emission Luminogens to Boost Three-Photon Absorption for Through-Skull Brain Imaging.

Three-photon fluorescence microscopic (3PFM) bioimaging is a promising imaging technique for visualizing the brain in its native environment thanks to its advantages of high spatial resolution and large imaging depth. However, developing fluorophores with strong three-photon absorption (3PA) and bright emission that meets the requirements for efficient three-photon fluorescence microscopic (3PFM) bioimaging is still challenging. Herein, four bright fluorophores with aggregation-induced emission features are facilely synthesized, and their powders exhibit high quantum yields of up to 56.

An unexpected non-conjugated AIEgen with a discrete dimer for pure intermolecular through-space charge transfer emission.

Manipulation of the charge transfer in donor-acceptor-type molecules is essential for the design of controllable aggregate luminescent materials. Apart from the traditional through-bond charge transfer (TBCT) systems which suffer from complicated structural design, poor tunability and low quantum efficiency, through-space charge transfer (TSCT) has been proved as an alternative yet facile strategy in tuning photophysical processes. In this work, by simply changing nucleophilic reaction bases, a traditional conjugated acrylonitrile AP1 and an unexpected non-conjugated AP2 with a carboxamide-functionalized oxirane linker could be obtained.

An Air-Stable Organic Radical from a Controllable Photoinduced Domino Reaction of a Hexa-aryl Substituted Anthracene.

Air-stable organic radicals and radical ions have attracted great attention for their far-reaching application ranging from bioimaging to organic electronics. However, because of the highly reactive nature of organic radicals, the design and synthesis of air-stable organic radicals still remains a challenge. Herein, an air-stable organic radical from a controllable photoinduced domino reaction of a hexa-aryl substituted anthracene is described.

Biologically Excretable Aggregation-Induced Emission Dots for Visualizing Through the Marmosets Intravitally: Horizons in Future Clinical Nanomedicine.

Superb reliability and biocompatibility equip aggregation-induced emission (AIE) dots with tremendous potential for fluorescence bioimaging. However, there is still a chronic lack of design instructions of excretable and bright AIE emitters. Here, a kind of PEGylated AIE (OTPA-BBT) dots with strong absorption and extremely high second near-infrared region (NIR-II) PLQY of 13.

Cyclization-Promoted Ultralong Low-Temperature Phosphorescence via Boosting Intersystem Crossing.

Ultralong organic phosphorescence holds great promise as an important approach for optical materials and devices. Most of phosphorescent organic molecules with long lifetimes are substituted with heavy atoms or carbonyl groups to enhance the intersystem crossing (ISC), which requires complicated design and synthesis. Here, we report a cyclization-promoted phosphorescence phenomenon by boosting ISC.

Robust Supramolecular Nano-Tunnels Built from Molecular Bricks*.

Herein we report a linear ionic molecule that assembles into a supramolecular nano-tunnel structure through synergy of trident-type ionic interactions and π-π stacking interactions. The nano-tunnel crystal exhibits anisotropic guest adsorption behavior. The material shows good thermal stability and undergoes multi-stage single-crystal-to-single-crystal phase transformations to a nonporous structure on heating.

Evoking Photothermy by Capturing Intramolecular Bond Stretching Vibration-Induced Dark-State Energy.

Development of highly effective approaches to desirable photothermal conversion agents is particularly valuable. Herein, we report a concept, namely, bond stretching vibration-induced photothermy, that serves as a mechanism to construct advanced photothermal conversion agents. As a proof-of-concept, two compounds (DCP-TPA and DCP-PTPA) with donor-acceptor (D-A) structures were synthesized.

New Wine in Old Bottles: Prolonging Room-Temperature Phosphorescence of Crown Ethers by Supramolecular Interactions.

Supramolecular macrocyclic hosts have long been used in smart materials. However, their triplet emission and regulation at crystal level is rarely studied. Herein, ultralong and universal room-temperature phosphorescence (RTP) is reported for traditional crown ethers.

"Seeing" and Controlling Photoisomerization by ()-/()-Isomers with Aggregation-Induced Emission Characteristics.

Efficient photoisomerization of chromophores is important in living systems, and structural constraints of protein pocket on chromophores are the probable reason for moving their dynamic reaction equilibrium forward. On the other hand, photochemical reaction to switch a molecule from one isomer to the other with different geometry and property in a high yield will continue to play a vital role in the synthetic chemistry and material science. Because of the important role of efficient photoisomerization, a biomimetic approach for "seeing" and controlling the photoisomerization is developed by using the technology of aggregation-induced emission (AIE) with supramolecular chemistry.

[2]Pseudorotaxane-Based Supramolecular Optical Indicator for the Visual Detection of Cellular Cyanide Excretion.

Cyanide is extremely hazardous to living organisms and the environment. Owing to its wide range of applications and high toxicity, the development of functional materials for cyanide detection and sensing is highly desirable. Host-guest complexation between bis(p-phenylene)-34-crown-10 H and N-methylacridinium salt G remarkably decreases the detection limit for cyanide anions compared with that of the guest itself.

Endo- and Exo-Functionalized Tetraphenylethylene ML Nanospheres: Fluorescence Emission inside a Confined Space.

The intrinsic relationship between the properties of green fluorescent protein (GFP) and its encapsulated small molecular light machine has spurred many biomimicking studies, aiming at revealing the detailed mechanism and further promoting its wide applications in different disciplines. However, how to build a similar confined microenvironment to mimic the cavity of a β-barrel and the fluorescence turn-on process is a fundamental challenge for both chemists and biologists. Herein, two distinct exo- and endo-functionalized tetraphenylethylene (TPE)-based ML nanospheres with precise distribution of anchored TPE moieties and unique photophysical properties were constructed by means of a coordination-driven self-assembly strategy.

Visualizing the Initial Step of Self-Assembly and the Phase Transition by Stereogenic Amphiphiles with Aggregation-Induced Emission.

Many highly ordered structures with smart functions are generated by self-assembly with stimuli responsiveness. Despite that electron microscopes enable us to directly observe the end products, it is hard to visualize the initial step and the kinetic stimuli-responsive behavior of self-assembly. Here, we report the design and synthesis of stereogenic amphiphiles, namely, ( Z)-TPE-OEG and ( E)-TPE-OEG, with aggregation-induced emission (AIE) characteristics from the hydrophobic tetraphenylethene core and thermoresponsive behavior from the hydrophilic oligoethylene glycol monomethyl ether chain.

Aggregation-Induced Emission Luminogen with Near-Infrared-II Excitation and Near-Infrared-I Emission for Ultradeep Intravital Two-Photon Microscopy.

Currently, a serious problem obstructing the large-scale clinical applications of fluorescence technique is the shallow penetration depth. Two-photon fluorescence microscopic imaging with excitation in the longer-wavelength near-infrared (NIR) region (>1100 nm) and emission in the NIR-I region (650-950 nm) is a good choice to realize deep-tissue and high-resolution imaging. Here, we report ultradeep two-photon fluorescence bioimaging with 1300 nm NIR-II excitation and NIR-I emission (peak ∼810 nm) based on a NIR aggregation-induced emission luminogen (AIEgen).

Multiple yet Controllable Photoswitching in a Single AIEgen System.

Seeking new methods to obtain elaborate artificial on-demand photoswitching with multiple functionalities remains challenging. Most of the systems reported so far possess only one specific function and their nonemissive nature in the aggregated state inevitably limit their applications. Herein, a tailored cyanostilbene-based molecule with aggregation-induced emission characteristic was synthesized and was found to exhibit efficient, multiple and controllable photoresponsive behaviors under different conditions.

Taco complex-templated highly regio- and stereo-selective photodimerization of a coumarin-containing crown ether.

Preorientation of the terminal coumarins of a crown ether with the assistance of taco-type host-guest complex formation promotes regio- and stereo-selectivity of coumarin photodimerization to give only the syn head-to-tail coumarin isomer.