Aggregation-Induced Emission Luminogens for Direct Exfoliation of 2D Layered Materials in Ethanol

© 2020 Wiley-VCH GmbH Aggregation-induced emission (AIE) luminogens are an important type of advanced functional materials with fantastic optical properties and have found potential applications in organic electronics, biochemistry, and molecular imaging. Herein, this article presents a novel application of AIE luminogens (AIEgens) for efficient exfoliation of layered transition metal dichalcogenides (TMDs, such as MoS2 and WSe2). From the 1H NMR spectroscopic analysis, the designed AIEgens can insert into the space between layers of MoS2 in ethanol solution and the dynamic molecular rotation against the weak interactions affords large-scale few-layer MoS2 nanosheets (7–8 layers) with enhanced smoothness. The 3D AIEgens play a significant role in preserving the crystal lattice of MoS2 even at high pressure (>15 GPa). More importantly, the new approach can also be used for exfoliation of WSe2 to achieve large-scale few-layer nanosheets. The present work thus provides a facile and high yielding synthetic method for accessing on a large scale 2D layered materials with enhanced properties for high-technology applications

A substitution-dependent light-up fluorescence probe for selectively detecting Fe3+ ions and its cell imaging application

Deliberate design of specific and sensitive molecular probes with distinctive physical/chemical properties for analyte sensing is of great significance. Herein, by taking advantage of the position-dependent substituent effects, an aggregation-induced emission featured iron (III) probe from ortho-substituted pyridinyl-functionalized tetraphenylethylene (TPE-o-Py) is synthesized. It displays high sensitivity and selectivity toward iron (III) detection. The recognition arises from the position isomer of ortho-substitution, and the fact that TPE-o-Py has a low acid dissociation constant (pKa) that is close to that of hydrolyzed Fe3+. Importantly, TPE-o-Py as a light-up fluorescence probe could be employed for Fe3+sensing in living cells with a pronounced red-shift in fluorescence emission

Specific two-photon imaging of live cellular and deep-tissue lipid droplets by lipophilic AIEgens at ultra-low concentration

Lipid droplets are highly associated with obesity, diabetes, inflammatory disorders and cancer. A reliable two-photon dye for specific lipid droplets imaging in live cells and live tissues at ultra-low concentration has rarely been reported. In this work, four new aggregation-induced emission luminogens (AIEgens) based on the naphthalene core were designed and synthesized for specific two-photon lipid droplets staining. The new molecules, namely NAP AIEgens, exhibit large Stokes shift (>110 nm), high solid-state fluorescence quantum yield (up to 30%), good two-photon absorption cross section (45–100 GM at 860 nm), high biocompatibility and good photostability. They could specifically stain lipid droplets at ultra-low concentration (50 nM) in a short time of 15 min. Such ultra-low concentration is the lowest value for lipid droplets staining in live cells reported so far. In vitro and ex vivo two-photon imaging of lipid droplets in live cells and live mice liver tissues were successfully demonstrated. In addition, selective visualization of lipid droplets in live mice liver tissues could be achieved at a depth of about 70 μm. These excellent properties render them as promising candidates for investigating lipid droplets-associated physiological and pathological processes in live biological samples

Regio- and stereoselective polymerization of diynes with inorganic comonomer: a facile strategy to conjugated poly(p-arylene dihalodiene)s with processability and postfunctionalizability

Copyright © 2018 American Chemical Society. Development of new methodologies for synthesizing polymers with novel structures and unique properties is a fundamentally important area in polymer science. Herein, a novel synthetic strategy to conjugated poly(p-arylene dihalodiene)s (PADs) with high regio- and stereoselectivity was developed. In the presence of PdBr 2 and CuBr 2 , the polymerizations of terminal alkynes proceeded smoothly in air without heating to generate PADs in high yields (up to 95.3%) with high molecular weights (M w up to 915 900). Low-cost inorganic CuBr 2 played dual roles as cocatalyst and comonomer. The PADs possessed good solubility and film-formi ng ability. Their thin films exhibited high refractive indices (1.7149-1.7245) and would be fabricated into well-resolved fluorescent photopatterns by photolithography. Thanks to the vinyl bromine functionality, the PADs could undergo efficient postmodification to afford polymers with more sophisticated structures and applications.

SI files for "Regio- and stereoselective polymerization of diynes with inorganic comonomer: A facile strategy to conjugated poly(p-arylene dihalodiene)s with processability and postfunctionalizability"

These are the SI files for "Regio- and stereoselective polymerization of diynes with inorganic comonomer: A facile strategy to conjugated poly(p-arylene dihalodiene)s with processability and postfunctionalizability".Abstract for associated article:Development of new methodologies for synthesizing polymers with novel structures and unique properties is a fundamentally important area in polymer science. Herein, a novel synthetic strategy to conjugated poly(p-arylene dihalodiene)s (PADs) with high regio- and stereoselectivity was developed. In the presence of PdBr 2 and CuBr 2 , the polymerizations of terminal alkynes proceeded smoothly in air without heating to generate PADs in high yields (up to 95.3%) with high molecular weights (M w up to 915 900). Low-cost inorganic CuBr 2 played dual roles as cocatalyst and comonomer. The PADs possessed good solubility and film-formi ng ability. Their thin films exhibited high refractive indices (1.7149-1.7245) and would be fabricated into well-resolved fluorescent photopatterns by photolithography. Thanks to the vinyl bromine functionality, the PADs could undergo efficient postmodification to afford polymers with more sophisticated structures and applications.</div

Clusterization-triggered emission: Uncommon luminescence from common materials

π-Conjugated chromophores have been investigated for many years and successful theoretical models have been developed to explain their photophysical properties. However, materials have appeared sporadically that do not fit within these existing models. Some of these materials possess entirely nonconjugated structures based on saturated C–C, C–O or C–N bonds, but their aggregates or solid-state forms show bright visible emission. This phenomenon is termed as clusterization-triggered emission (CTE) and the materials possessing the property are labeled clusteroluminogens. In this review, we provide a brief summary of the recent development of clusteroluminogens. The materials are classified into three categories: polymers (natural and synthetic polymers), small molecules (with and without aromatic rings) and metal clusters. Possible luminescence mechanisms underpinning the different categories of clusteroluminogens are analyzed individually. Finally, we put forward a comprehensive theory of the through-space conjugation (TSC) for these chromophores. Based on the CTE effect and TSC theory, various applications have been envisioned, for example in the areas of process monitoring, structural visualization, sensors, and probes. It is anticipated that this new research direction will bring many breakthroughs, not only in the theoretical areas, but also in these advanced applications of light-emitting materials