Recent research into graphene-based materials is largely focused on graphene quantum dots (GQDs) and their optical properties. A facile method has been developed to extract GQDs from reduced oxide (RGO) by the ozonation pre-oxide method. The as-prepared GQDs, which were 2–5 nm in diameter, exhibited strong fluorescence activity ranging ∼355 ∼440 nm. prepared possessed with yields 3.18% 9.48%. What's more, properties of could be determined tuning pH system. We speculated mechanisms ozonation,...

An efficient tandem reaction for the asymmetric synthesis of six-membered spirocyclic oxindoles has been successfully developed through a formal [2+2+2] annulation strategy. The amine-catalysed stereoselective Michael addition aliphatic aldehydes to electron-deficient olefinic oxindole motifs gave chiral C3 components, which were further combined with diverse electrophiles (activated olefins or imines) afford versatile molecular complexity (up six contiguous stereogenic centres, high...

The efficient assembly of hydroindane derivatives incorporating a spirooxindole motif was realized via new three-component domino reaction (E)-4-(1-methyl-2-oxoindolin-3-ylidene)-3-oxobutanoates and two molecules α,β-unsaturated aldehydes under quadruple iminium−enamine−iminium−enamine catalysis. complex products bearing six contiguous stereogenic centers were obtained in excellent stereoselectivities (96−>99% ee, >99% de).

The direct asymmetric allylic alkylation of β,γ-butenolides with MBH carbonates to access γ,γ-disubstituted butenolides containing adjacent quaternary and tertiary chiral centers has been presented in excellent stereoselectivities (86−96% ee, dr >95:5) moderate good yield (50−83%). Their synthetic utility well demonstrated by the facile construction bicyclic lactones bearing 4−5 stereogenic centers.

In this work, we demonstrated a highly sensitive inductively coupled plasma mass spectrometric (ICPMS) method for the determination of human carcinoembryonic antigen (CEA), which combined inherent high sensitivity elemental measurement with signal amplification catalytic silver deposition on immunogold tags. The procedure was easy to handle and required cheap reagents, greatly enhanced 60-fold after 15 min procedure. experimental conditions, including detection gold by ICPMS, immunoassay...

Fluoride ion (F–) is one of the most harmful elements in drinking water. Over-intake F– can result dental fluorosis, kidney failure, or DNA damage. Therefore, developing affordable, equipment-free, and reliable methods for detection an important goal. In this work, a series mixed lanthanide metal–organic frameworks were synthesized using triazine-based planar ligand, 4,4′,4″-s-triazine-2,4,6-triyltribenzoate (TATB) ions (Tb3+ Eu3+). The luminescent color Tb/Eu(TATB) be finely modulated by...

Abstract Background Verticillium wilt, caused by the fungal pathogen dahliae , is most severe disease in cotton ( Gossypium spp.), causing great lint losses worldwide. Disease management could be achieved field if genetically improved, resistant plants were used. However, interaction between V. and a complicated process, its molecular mechanism remains obscure. To understand better defense response to this as means for obtaining more tolerant cultivars, we monitored transcriptome profiles of...

Entscheidendes Enal: Die ausgezeichnet β,γ-regioselektive Titelreaktion unter Dienamin-Katalyse führte effizient zu hoch diastereo- und enantiomerenangereicherten Cyclohexenderivaten mit unterschiedlichen Substituenten (siehe Schema; EWG=elektronenziehende Gruppe, TMS=Trimethylsilyl). Detailed facts of importance to specialist readers are published as "Supporting Information". Such documents peer-reviewed, but not copy-edited or typeset. They made available submitted by the authors. Please...

The asymmetric inverse-electron-demand aza-Diels–Alder reaction of N-Ts-1-aza-1,3-butadienes derived from 3-argiocarbonylcoumarins and acetaldehyde has been developed using chiral secondary aminocatalysis, giving tricyclic chroman-2-one derivatives in high enantioselectivities (up to 95% ee).

A simple yet ultrasensitive UV photochemical vapor generation (photo-CVG) is proposed for the speciation analysis of Se(IV) and Se(VI). The new photo-CVG, which based on or Se(VI) reacting with an organic acid under different reaction conditions, can be coupled to AFS ICP-MS in real samples such as table salt water without chromatographic separation. At low temperature, only photochemically converted selenium volatile species, this used its selective determination; however, by using boiling...

Metal-semiconductor composites are promising candidates for surface-enhanced Raman scattering (SERS) substrates, but their inert basal plane, poor active sites, and limited stability hamper commercial prospects. Herein, we report a three-dimensional CoP nanowire array decorated with Au nanoparticles on carbon cloth (Au@CoP/CC) as self-supporting flexible SERS substrate. The spontaneously grew the surface of to form efficient hot spots by redox reaction HAuCl4 without any additional reducing...

In this work, a boric-acid-modified Fe

Ideal for scaffold diversity synthesis: The first organocatalytic direct vinylogous Michael addition of N-Boc α,β-unsaturated γ-butyrolactam to aldehydes has been developed. products with multiple orthogonal sets functionalities were transformed into diverse enantioenriched natural-product-like or drug-like molecules fused bi-, tri-, polycyclic scaffolds (see scheme), which might have potential biologically related studies. Detailed facts importance specialist readers are published as...

A novel, green and efficient post-column oxidation method using Fe(3)O(4) magnetic nanoparticles (MNPs) was developed to on-line convert hydride generation/cold vapor generation (HG/CV) inactive species their active without microwave/UV irradiation. It applied high performance liquid chromatography HG/CV atomic fluorescence spectrometry (HPLC-HG/CV-AFS) enable sensitive speciation analysis of both species. Inorganic mercury (Hg(2+)), methylmercury (MeHg), ethylmercury (EtHg) phenylmercury...

A disposable, instrument-free, height readout paper-based analytical device (HR-PAD) based on a paper strip inkjet-printed with CdTe quantum dots (QDs) was developed for the sensitive speciation analysis of Ag+ and silver nanoparticles (AgNPs). When is immersed into sample solution, capillary action draws it through surface any in solution quenches fluorescence QDs via cation exchange reaction between QDs, quenched band being proportional to concentration Ag+. In contrast, quenching cannot...

Speciation analysis of mercury in hair facilitates accurate evaluation exposure to humans and insights into the intertransformation different species human body. However, conventional hyphenated techniques used for speciation usually require expensive instruments a complex interface. In this work, compact miniaturized point discharge (PD) atomic emission spectrometer was utilized as detector gas chromatography mercury. Mercury extracted from were derivatized their volatile with NaBEt4...

Distinguishing the delicate structural differences among molecules is a critical and challenging task in biological/chemical analysis. A molecular decoding strategy has recently become promising to differentiate similar molecules, which advantageous over common sensing methods mostly used for detecting single target. However, design of an ideal decoder still strictly hindered by tailored preparation probes particular severe lack widespread feasibility. We herein first time proposed use...

A simple and miniature analytical system was developed to determine Hg Cd in small amounts of samples by integrating flow injection capillary liquid electrode discharge (CLED) optical emission spectrometry (OES) microplasma-induced vapor generation (PIVG) atomic fluorescence (AFS). With the assistance inherent driving force arising from solution vaporization microplasma, sample automatically transported into chamber wherein analytes were simultaneously excited generate their lines converted...

Arginine is considered as a biomarker of cystinuria and other diseases, thus, it urgency to develop simple rapid method with high sensitivity selectivity for arginine detection meet the demand on-site analysis bedside diagnosis. In this work, lanthanide metal–organic framework, La(TATB), was prepared using triazine-based planar ligand, 4,4′,4″-s-triazine-2,4,6-triyltribenzoate (H3TATB), ion (La3+). La(TATB) can be used highly photosensitive agent activate molecular oxygen 1O2 achieve...

A new and unique photo-induced mercury cold/chemical vapor generation (PI-CVG), which directly uses sample matrix as a reductant, was proposed for atomic fluorescence spectrometric detection of trace in wine or liquor samples. The method thus termed matrix-assisted PI-CVG. With the ultraviolet radiation (UV), (ethanol) can reduce compounds ions to mercury, Hg0, is subsequently swept (by argon carrier gas) into an spectrometer measurements. Under optimized experimental conditions, LOD found...

On-line preconcentration and in situ photochemical vapor generation a coiled reactor was proposed for speciation analysis of ultratrace mercury methylmercury (Hg2+ MeHg+) by using atomic fluorescence spectrometric detection. Diethyldithiocarbamate (DDTC) served here not only as chelating reagent to form hydrophobic compound on-line but also reductant desorption from the reactor. Optimum conditions generation, well potential Hg2+ MeHg+, were carefully investigated. Limit detection (LOD, 3σ)...