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Fluorescence sensing is crucial to studying biological processes and diagnosing diseases, especially in the second near‐infrared (NIR‐II) window with reduced background signals. However, it's still a great challenge to construct "off‐on" sensors when the sensing wavelength extends into the NIR‐II region to obtain higher imaging contrast, mainly due to the difficult synthesis of spectral overlapped quencher. Here, we present a new fluorescence quenching strategy, which utilizes steric hindrance quencher (SHQ) to tune the molecular packing state of fluorophores and suppress the emission signal. Density functional theory (DFT) calculations further reveal that large SHQs can competitively pack with fluorophores and prevent their self‐aggregation. Based on this quenching mechanism, a novel activatable "off‐on" sensing method is achieved via bio‐analyte responsive invalidation of SHQ, namely the Steric Hindrance Invalidation geNerated Emission (SHINE) strategy. As a proof of concept, the ClO−‐sensitive SHQ lead to the bright NIR‐II signal release in epileptic mouse hippocampus under the skull and high photon scattering brain tissue, providing the real‐time visualization of ClO− generation process in living epileptic mice. [ABSTRACT FROM AUTHOR]

The given text provides information about the synthesis and characterization of various compounds. The compounds were prepared using a general procedure and purified by flash chromatography. The yield, physical properties, and spectroscopic data of each compound are provided. The compounds synthesized include N-Cyclohexyl-N-methyl-4-((3-oxo-3,4-dihydro-2H-benzo[b][1,4]oxazin-7-yl)oxy)butanamide, 6-Methyl-2H-benzo[b][1,4]oxazin-3(4H)-one, 6-Ethyl-2H-benzo[b][1,4]oxazin-3(4H)-one, 6-Propyl-2H-benzo[b][1,4]oxazin-3(4H)-one, 6-Methoxy-2H-benzo[b][1,4]oxazin-3(4H)-one, 1-Oxa-4-azaspiro[4.5]deca-6,9-diene-3,8-dione, 7-Fluoro-2H-benzo[b][1,4]oxazin-3(4H)-one, and 6-Fluoro-2H-benzo[b][1,4]oxazin-3(4H)-one. [Extracted from the article]

High refractive index polymers (HRIPs) have drawn attention for their optoelectronic applications and HRIPs with excellent transparency and facile preparation are highly demanded. Herein, sulfur-containing all organic HRIPs with refractive indices up to 1.8433 at 589 nm and excellent optical transparency even in one hundred micrometre scale in the visual and RI region as well as high weight-average molecular weights (up to 44500) are prepared by our developed organobase catalyzed polymerization of bromoalkynes and dithiophenols in yields up to 92%. Notably, the fabricated optical transmission waveguides using the resultant HRIP with the highest refractive index display a reduced propagation loss compared with that generated by the commercial material of SU-8. In addition, the tetraphenylethylene containing polymer not only exhibits a reduced propagation loss, but also is used to examine the uniformity and continuity of optical waveguides with naked eyes because of its aggregation-induced emission feature. The easy preparation of high efractive index transparent polymers is highly desirable owing to their interesting optoelectronic applications. Here, the authors apply an organobase catalyzed polymerization of bromoalkynes and dithiophenols to produce sulfur-containing all organic high refractive index polymers with excellent optical transparency. [ABSTRACT FROM AUTHOR]

In this work, we synthesized mesoporous silica nanoparticles (MSNs) and periodic mesoporous organosilica nanoparticles containing bridging groups of ethylene (E-PMO) and phenylene (P-PMO) and compared their adsorption properties using D-limonene (Lim), myrcene (Myr), and cymene (Cym) as model guest molecules. For the selected nanoparticles of ~100 nm in diameter, the loading capacity to the volatile fragrances was in the order of P-PMO < E-PMO < MSN, consistent with the trend of increasing total pore volume. For example, P-PMO, E-PMO, and MSN had a Lim uptake of 42.2 wt%, 47.3 wt%, and 62.7 wt%, respectively, which was close to their theoretical adsorption capacity. Under isothermal thermogravimetric analysis conditions (30 °C, a N2 flow of 1 mL min−1), the lowest fragrance release of ~56% over 24 h was observed for P-PMO, followed by E-PMO (74–80%), and MSN (~89%). The release kinetics of the fragrant molecules from MSN and PMO materials can be well described by first-order and Weibull models, respectively. Moreover, the incorporation of Lim-loaded P-PMO NPs in an aqueous solution of regenerated silk fibroin provided a composite coating material suitable for perishable fruit preservation. The active layer deposited on fruit peels using dip coating showed good preservation efficacy, enabling the shelf-life of mangoes in a highly humid and hot atmosphere (30–35 °C, 75–85% RH) to be extended to 6 days. [ABSTRACT FROM AUTHOR]

It is significant and challenging to use CO2 to produce polymeric materials, especially with olefins. Here, a novel strategy named "scrambling polymerizations" is designed and performed for the copolymerization of a CO2‐and‐1,3‐butadiene‐derived valerolactone, 3‐ethylidene‐6‐vinyltetrahydro‐2H‐pyran‐2‐one (EVL), with ϵ‐caprolactone (CL) to prepare polyesters. Anionic ring‐opening polymerization of CL and conjugated addition oligomerization of EVL take place individually to form PCL and EVL oligomers, respectively. Then EVL oligomers insert into PCL by transesterification resulting in polyester P(CL‐co‐EVL) with a tunable topology and composition. The non‐cytotoxic and degradable polyester network with elongation at break of >600 % can be used as an elastomer. We propose a method to provide polyester elastomers from CO2 and olefins for the first time, and expand the potential of transformation from sustainable feedstocks to polymeric materials. [ABSTRACT FROM AUTHOR]