Visible light-driven and substrate-promoted alkenyltrifluoromethylation of alkenes to synthesize CF-functionalized 1,4-naphthoquinones.

The first example of the visible light-driven and substrate-promoted three-component alkenyltrifluoromethylation of alkenes is developed. This approach uses easily available alkenes, 2-arylamino-1,4-naphthoquinones and Togni reagent as the reactants, and describes good functionality tolerance. The reaction offers a precise synthesis of valuable CF-functionalized 1,4-naphthoquinones and can be applied in late-stage modification of natural products and pharmaceuticals.

Photoredox-Catalyzed Synthesis of 3,3-Difluoro-γ-lactams via 1,5-Hydrogen Atom Transfer-Involved Alkyne Difunctionalization and C-N Cleavage.

This manuscript describes the application of a 1,5-hydrogen atom transfer strategy in photoredox-catalyzed hydrodifluoroalkylation of alkynes. The approach utilizes a sequential cascade process of difluoroalkylation, 1,5-hydrogen atom transfer, C(sp)-N cleavage, and intramolecular condensation cyclization to accomplish efficient [3 + 2] cycloaddition of readily available propargylamines with halodifluoroacetates (or halodifluoroacetamides). The reaction allows for the selective construction of polysubstituted 3,3-difluoro-γ-lactams with good functional group tolerance, and further transformations of the resulting 3,3-difluoro-γ-lactams into different building blocks are also accomplished.

Oxidative Aminotrifluoromethylation of 1,4-Naphthoquinone.

A strategy for convenient and precise oxidative aminotrifluoromethylation of 1,4-naphthoquinone with the Togni reagent and amines has been demonstrated via a radical process. This method allows efficient access for the preparation of a wide range of CF-functionalized 1,4-naphthoquinones under mild conditions, and its application in late-stage modification of drug molecules is achieved. Mechanistic studies indicate that 1,4-naphthoquinone serves as both a substrate and a catalyst and that the Togni reagent plays a dual role of a substrate and an oxidant.

Base-Dependent Divergent Carbodifluoroalkylation and Halodifluoroalkylation of Alkenes under Visible-Light Irradiation.

Organic molecules containing a difluoroalkyl group are valuable and versatile chemicals because of their unique physicochemical and biological properties. Accordingly, the development of efficient and practical difluoroalkylation for the preparation of these compounds is important and attractive. Herein, we demonstrate photoredox-catalyzed and base-dependent selective carbodifluoroalkylation and halodifluoroalkylation of alkenes using readily available 2-(allyloxy)arylaldehydes [or 2-(allylamino)arylaldehydes] and XCFCOOEt (or BrCFCONRR) as starting materials.

Rare-earth-free up and down-conversion dual-emission carbon dots for Cu sensing.

In this work, up- and down-conversion dual-emission CDs without rare-earth (UD D-CDs) were synthesized using RhB and 1,4-Diaminoanthraquinone as precursors. The synthesized UD D-CDs exhibited dual emissions at 496 and 580 nm under 260 and 865 nm excitation, respectively. The fluorescence emission mechanism, including contributions from carbon nuclei, surface states, molecular states, and internal defect states, was discussed through the separation and purification of UD D-CDs.

The novel up/down-conversion dual-emission carbon dots for dual-channel ratiometric fluorescence detection of pH and Cu.

Up/down-conversion dual-emission carbon dots (U/D-CDs) are rare and have potential in analytical sensing. Herein, a kind of novel U/D-CDs was prepared successfully by a one-step solvothermal method. The prepared U/D-CDs exhibited similar dual-emission behaviors at excitation wavelengths of 300 nm and 680 nm, respectively.

Texture Feature Extraction from H NMR Spectra for the Geographical Origin Traceability of Chinese Yam.

Adulteration is widespread in the herbal and food industry and seriously restricts traditional Chinese medicine development. Accurate identification of geo-authentic herbs ensures drug safety and effectiveness. In this study, H NMR combined intelligent "rotation-invariant uniform local binary pattern" identification was implemented for the geographical origin confirmation of geo-authentic Chinese yam (grown in Jiaozuo, Henan province) from Chinese yams grown in other locations.

Modular-Approach Synthesis of Giant Molecule Acceptors via Lewis-Acid-Catalyzed Knoevenagel Condensation for Stable Polymer Solar Cells.

The operational stability of polymer solar cells is a critical concern with respect to the thermodynamic relaxation of acceptor-donor-acceptor (A-D-A) or A-DA'D-A structured small-molecule acceptors (SMAs) within their blends with polymer donors. Giant molecule acceptors (GMAs) bearing SMAs as subunits offer a solution to this issue, while their classical synthesis via the Stille coupling suffers from low reaction efficiency and difficulty in obtaining mono-brominated SMA, rendering the approach impractical for their large-scale and low-cost preparation. In this study, we present a simple and cost-effective solution to this challenge through Lewis acid-catalyzed Knoevenagel condensation with boron trifluoride etherate (BF  ⋅ OEt ) as catalyst.

Geometry design of tethered small-molecule acceptor enables highly stable and efficient polymer solar cells.

With the power conversion efficiency of binary polymer solar cells dramatically improved, the thermal stability of the small-molecule acceptors raised the main concerns on the device operating stability. Here, to address this issue, thiophene-dicarboxylate spacer tethered small-molecule acceptors are designed, and their molecular geometries are further regulated via the thiophene-core isomerism engineering, affording dimeric TDY-α with a 2, 5-substitution and TDY-β with 3, 4-substitution on the core. It shows that TDY-α processes a higher glass transition temperature, better crystallinity relative to its individual small-molecule acceptor segment and isomeric counterpart of TDY-β, and a more stable morphology with the polymer donor.

A pH/GSH dual responsive nanoparticle with relaxivity amplification for magnetic resonance imaging and suppression of tumors and metastases.

Engineered magnetic nanoparticles combining diagnosis and therapy functions into one entity hold great potential to rejuvenate cancer treatment; however, they are still constrained by the "always on" signals and unsatisfactory therapeutic effect. Here, we report an intelligent theranostic probe based on MnO tetragonal bipyramids (MnTBs), which simultaneously respond to H and glutathione (GSH) with high sensitivity and quickly decompose to release Mn in mild acidic and reductive intracellular environments. Mn binds to the surrounding proteins to achieve a remarkable relaxivity amplification and selectively brighten the tumors.

Three-Component Perfluoroalkylvinylation of Alkenes Enabled by Dual DBU/Fe Catalysis.

Herein, a simple and efficient strategy that involves dual 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)/iron-catalyzed alkene perfluoroalkylvinylation by using perfluoroalkyl iodides and 2-aminonaphthalene-1,4-diones as coupling partners is demonstrated.

Effect of Transgenic Cotton Expressing Bt Cry1Ac or Cry1Ab/Ac Toxins on Lacewing Larvae Mediated by Herbivorous Insect Pests.

A simple food chain (plant, insect pests, and predatory arthropods) in an agro-ecosystem was set up here as a model system to elucidate the potential effect of transgenic (Bt) cotton on non-target organisms. The system included transgenic/non-transgenic cotton, neonate larvae of three herbivorous insects (, , and ), and predatory lacewing larvae ( spp.), which represent the first, second, and third trophic levels, respectively.

Bifunctional 1,8-Diazabicyclo[5.4.0]undec-7-ene for Visible Light-Induced Heck-Type Perfluoroalkylation of Alkenes.

This article presents simple and efficient 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)-promoted Heck-type alkene perfluoroalkylation under visible light irradiation.

Dye-based dual-emission Eu-MOF synthesized by Post-modification for the sensitive ratio fluorescence visualization sensing of ClO.

As we all know, excessive hypochlorite will be transformed into highly toxic substances, while insufficient hypochlorite can not completely kill bacteria and viruses in water. Therefore, it is desirable to develop a new analytical method to detect ClO in environmental water. Here, a novel and simple fluorescence sensor was constructed for monitoring ClO by an effective strategy.

Low-cost synthesis of small molecule acceptors makes polymer solar cells commercially viable.

The acceptor-donor-acceptor (A-D-A) or A-DA'D-A structured small molecule acceptors (SMAs) have triggered substantial progress for polymer solar cells (PSCs). However, the high-cost of the SMAs impedes the commercial viability of such renewable energy, as their synthesis via the classical pyridine-catalyzed Knoevenagel condensation usually suffers from low reaction efficiency and tedious purifying work-up. Herein, we developed a simple and cheap boron trifluoride etherate-catalyzed Knoevenagel condensation for addressing this challenge, and found that the coupling of the aldehyde-terminated D unit and the A-end groups could be quantitatively finished in the presence of acetic anhydride within 15 minutes at room temperature.

Fluorinated Perylene-Diimides: Cathode Interlayers Facilitating Carrier Collection for High-Performance Organic Solar Cells.

Organic solar cells (OSCs) have experienced rapid progress with the innovation of near-infrared (NIR)-absorbing small-molecular acceptors (SMAs), while the unique electronic properties of the SMAs raise new challenges in relation to cathode engineering for effective electron collection. To address this issue, two fluorinated perylene-diimides (PDIs), PDINN-F and PDINN-2F, are synthesized by a simple fluorination method, for application as cathode interlayer (CIL) materials. The two bay-fluorinated PDI-based CILs possess a lower lowest unoccupied molecular orbital (LUMO) energy level of ≈-4.

Fe-Catalyzed Radical Trifluoromethyl-Alkenylation of Alkenes or Alkynes with 2-Amino-1,4-naphthoquinones.

The first Fe-catalyzed three-component radical trifluoromethyl-alkenylation of alkenes with 2-amino-1,4-naphthoquinones and CFSONa is reported. The developed reaction enables the highly regioselective preparation of a variety of valuable CF-substituted 1,4-naphthoquinones in acceptable yields. In the light of the catalytic system, alkynes smoothly afford the corresponding three- or four-component trifluoromethyl-alkenylation products.

One-pot hydrothermal synthesis of Si-doped carbon quantum dots with up-conversion fluorescence as fluorescent probes for dual-readout detection of berberine hydrochloride.

Here, the high fluorescent silicon-doped carbon quantum dots (Si-CQDs) were prepared by a facile and one-pot hydrothermal assay using 3-aminopropyltrimethoxysilane as the carbon and silicon source. The prepared Si-CQDs exhibit favorable water-soluble, high-temperature resistance, acid resistance, alkali resistance, high ionic strength resistance, high photostability, film-forming ability and solid-state fluorescence. Compared to other Si-CQDs that have been reported, the prepared Si-CQDs show unique up-conversion fluorescence.

A highly sensitive dual-readout assay for perfluorinated compounds based CdTe quantum dots.

Perfluorooctanoic acid (PFOA) and Perfluorooctane sulfonate (PFOS) are two typical perfluorinated compounds (PFCs) that poss potential ecological toxicity. In this work, a fluorescence and resonance light scattering (RLS) dual-readout strategy for the detection of PFCs at picomole level based on the water-soluble CdTe quantum dots (CdTe QDs) has been proposed. It is found that the CdTe QDs exhibit a quenching in the presence of PFCs and thus serve as useful probes for PFCs.

Fluorinated Ionic Liquid Based Multicolor F MRI Nanoprobes for In Vivo Sensing of Multiple Biological Targets.

Multicolor imaging, which maps the distribution of different targets, is important for in vivo molecular imaging and clinical diagnosis. Fluorine 19 magnetic resonance imaging ( F MRI) is a promising technique because of unique insights without endogenous background or tissue penetration limit. Thus multicolor F MRI probes, which can sense a wide variety of molecular species, are expected to help elucidate the biomolecular networks in complex biological systems.

Unprecedented observation and characterization of sulfur-centred bifurcated hydrogen bonds.

Owing to the small electronegativity of the sulfur atom, it is commonly supposed that at most one weak H-bond can be formed between a sulfur atom and an H-bond donor. In this paper, an unprecedented 2 : 1 binding species generated from two molecules of phenol and a molecule of thioether was observed and characterized by various nuclear magnetic resonance (NMR) techniques, Fourier transform-infrared (FT-IR) techniques and density functional theory (DFT) calculations, revealing the formation of sulfur-centred O-H⋯S⋯H-O bifurcated H-bonds. This work may provide a simple and efficient method for the quantitative analysis of weak H-bonds between small organic molecules.

Spectroscopic Study of the Behavior of Mo(VI) and W(VI) Polyanions in Sulfuric-Phosphoric Acid Mixtures.

The solution chemistry of Mo(VI) and W(VI) in mixtures of sulfuric and phosphoric acids is relevant to the development of practicable hydrometallurgical processes for the recovery and separation of these two elements from low-grade scheelite ores. The behavior of Mo(VI) and W(VI) in such mixtures has been studied using X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), nuclear magnetic resonance (NMR), and small-angle X-ray scattering (SAXS) spectroscopies, along with electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS). Where applicable, these techniques have produced a self-consistent picture of the similarities and differences between the chemical speciation of Mo(VI) and W(VI) as functions of solution composition, mostly at a constant phosphorous/metal (P/M; M = Mo(VI) or W(VI)) ratio of ∼1.

A Fluorinated Ionic Liquid-Based Activatable F MRI Platform Detects Biological Targets.

F magnetic resonance imaging (F MRI) is a promising technique for molecular imaging and clinical diagnosis, benefiting from its negligible background and unlimited tissue penetration depth. However, the development of F probes with good water solubility and versatile functions for bioresponsive and practical applications remains a challenge. Here, we report fluorinated ion liquids (ILs) as a new type of fluorine agents and build a fluorinated ionic liquid-based activatable F MRI platform (FILAMP), which relies on the phase transition of ILs.

A pH-Activatable MnCO Nanoparticle for Improved Magnetic Resonance Imaging of Tumor Malignancy and Metastasis.

Engineered magnetic nanoparticles have been extensively explored for magnetic resonance imaging (MRI) diagnosis of a tumor to improve the visibility. However, most of these nanoparticles display "always-on" signals without tumor specificity, causing insufficient contrast and false positives. Here, we provide a new paradigm of MRI diagnosis using MnCO nanorhombohedras (MnNRs) as an ultrasensitive -weighted MRI contrast agent, which smartly enhances the MR signal in response to the tumor microenvironment.

Application of Bifunctional 2-Amino-1,4-naphthoquinones in Visible-Light-Promoted Photocatalyst-Free Alkene Perfluoroalkyl-Alkenylation.

A simple and practical photochemical strategy for intermolecular perfluoroalkyl-alkenylation of alkenes with 2-amino-1,4-naphthoquinones and perfluoroalkyl iodides has been demonstrated under visible-light irradiation. Mechanistic studies reveal that easily available 2-amino-1,4-naphthoquinone substrates can serve as efficient photosensitizers to activate perfluoroalkyl iodides through a photoredox process. Therefore, the developed radical relay reaction proceeds smoothly without additional transition metals and photocatalysts.