Rhodium-catalyzed annulative approach to N-N axially chiral biaryls C-H activation and dynamic kinetic transformation.

N-N axially chiral biaryls represent a rarely explored class of atropisomeric compounds. We hereby report rhodium-catalyzed enantioselective [4 + 2] oxidative annulation of internal alkynes with benzamides bearing two classes of N-N directing groups. The coupling occurs under mild conditions NH and CH annulation through the dynamic kinetic transformation of the directing group and is highly enantioselective with good functional tolerance.

Rhodium-catalyzed atroposelective access to trisubstituted olefins C-H bond olefination of diverse arenes.

The atroposelective synthesis of axially chiral acyclic olefins remains a daunting challenge due to their relatively lower racemization barriers, especially for trisubstituted ones. In this work, atroposelective C-H olefination has been realized for synthesis of open-chain trisubstituted olefins C-H activation of two classes of (hetero)arenes in the coupling with sterically hindered alkynes. The employment of phenyl -methoxycarbamates as arene reagents afforded phenol-tethered olefins, with the carbamate being a traceless directing group.

Highly sensitive ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry detection method for levoglucosan based on Na enhancing its ionization efficiency.

The sensitive determination of levoglucosan in aqueous samples has great significance for the study of biomass burning. Although some sensitive high-performance liquid chromatography/mass spectrometry (HPLC/MS) detection methods have been developed for levoglucosan, there are still plenty of shortcomings, such as complicated sample pre-treatment procedures, large-amount sample requirements, and poor reproducibility. Herein, a new method for the determination of levoglucosan in the aqueous sample was developed using ultra-performance liquid chromatography with triple quadrupole mass spectrometry (UPLC-MS/MS).

Rhodium-catalyzed enantioselective C-H alkynylation of sulfoxides in diverse patterns: desymmetrization, kinetic resolution, and parallel kinetic resolution.

Rhodium-catalyzed enantioselective C-H alkynylation of achiral and racemic sulfoxides is disclosed with alkynyl bromide as the alkynylating reagent. A wide range of chiral sulfoxides have been constructed in good yield and excellent enantioselectivity (up to 99% ee, -factor up to > 500) desymmetrization, kinetic resolution, and parallel kinetic resolution under mild reaction conditions. The high enantioselectivity was rendered by the chiral cyclopentadienyl rhodium(iii) catalyst paired with a chiral carboxamide additive.

Correction: Photodynamic antimicrobial chemotherapy with cationic phthalocyanines against planktonic and biofilm cultures.

[This corrects the article DOI: 10.1039/C7RA06073D.].

Preparation and electrical properties of inorganic electride [YTiO](2e).

Oxygen-depleted samples [YTiO ](2e) (0 ≤ ≤ 1.0) were prepared by reducing YTiO powders at 500 °C to 650 °C using CaH as a reductive agent, where represents the content of , which was determined by thermogravimetric analysis. Powder X-ray diffraction patterns illustrate that the pure pyrochlore phase is kept for the samples with ≤ 1.

Rapid and highly specific detection of site-specific 5-hydroxymethylcytosine based on peroxotungstate oxidation and mismatch ligation-based LAMP.

We have developed a rapid and specific method for site-specific 5-hydroxymethylcytosine (5hmC) quantification at single-base resolution. This bisulfite-free method integrates the peroxotungstate oxidization with the mismatched probe-assisted ligation to guarantee the specificity. Moreover, the high-efficiency LAMP also makes the proposed method suitable for the detection of low-content samples.

Formation mechanism of zigzag patterned P(NIPAM--AA)/CuS composite microspheres by biomimetic mineralization for morphology modulation.

Poly(-isopropylacrylamide--acrylic acid)/copper sulfide (P(NIPAM--AA)/CuS) composite microspheres with variable zigzag patterned surfaces have been synthesized by employing an biomimetic mineralization reaction between HS and Cu immersed in P(NIPAM--AA) microspheres for morphology modulation. The morphology and composition of the P(NIPAM--AA)/CuS composite microspheres with zigzag patterned surfaces prepared in different conditions were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectrometry (FT-IR). The polymeric microgels swelled by Cu(Ac) solution after freeze-drying treatment were of porous structure, indicating that there were polymeric frameworks and rich-water domains in the microgels before the deposition.

Ultra-specific genotyping of single nucleotide variants by ligase-based loop-mediated isothermal amplification coupled with a modified ligation probe.

Specific and accurate detection of single nucleotide variants (SNVs) plays significant roles in pathogenic gene research and clinical applications. However, the sensitive but ultra-specific detection of rare variants in biological samples still remains challenging. Herein, we report a novel, robust and practical SNV assay by integrating the outstanding features of high selectivity of an artificial mismatched probe, and the powerful loop-mediated isothermal amplification.

Fluorescent sensing platform based on green luminescence carbon dots and AuNPs for clenbuterol detection in pork liver.

In this paper, water-soluble green fluorescent carbon dots (G-CDs) were prepared using -phenylenediamine and glutathione (GSH) as the precursors. The G-CDs exhibit excellent optical properties, and the maximum emission wavelength is located at 522 nm (under 410 nm excitation), which greatly overlaps with the absorption spectrum of AuNPs. Consequently, an effective "off-on" fluorescent sensing platform involved in G-CDs and AuNPs for detection of clenbuterol (CLB) was constructed.

Three-dimensional graphene encapsulated Ag-ZnFeO flower-like nanocomposites with enhanced photocatalytic degradation of enrofloxacin.

Three-dimensional (3D) Ag-ZnFeO-reduced graphene oxide (rGO) was successfully synthesized using a hydrothermal and photo-reduction method, and the morphological differences of the materials were observed. Their photocatalytic activity was evaluated by photocatalytic degradation of enrofloxacin (ENR) under visible-light irradiation. The results indicated that Ag-ZnFeO-rGO exhibited superior photocatalytic properties and good stability.

Synthetic and thermal studies of four insensitive energetic materials based on oxidation of the melamine structure.

Oxidation of nitrogen-rich aromatic heterocycles has a significant impact on the development of energetic materials. 2,4,6-Triamino-1,3,5-triazine-1,3-dioxide (MDO) is a promising insensitive energetic backbone obtained from melamine under strong oxidation conditions with impressive thermal behaviors and detonation performances. In this paper, MDO was prepared with improved yields of 85% and its thermal behavior, non-isothermal decomposition kinetics and gas products were investigated in detail.

A comparative study of the structures, thermal stabilities and energetic performances of two energetic regioisomers: 3(4)-(4-aminofurazan-3-yl)-4(3)-(4-nitrofurazan-3-yl)furoxan.

Although energetic regioisomers have attracted intensive attention due to their interesting structure-property correlation, their effective synthesis and accurate identification has remained very difficult. In this paper, we synthesized two energetic regioisomers, namely 3-(4-aminofurazan-3-yl)-4-(4-nitrofurazan-3-yl)furoxan (ANFF-34) and 4-(4-aminofurazan-3-yl)-3-(4-nitrofurazan-3-yl)furoxan (ANFF-43), a controllable strategy with improved yields of 32% and 38%, respectively. The structures of ANFF-34 and ANFF-43 were unambiguously identified using comparative studies of N NMR and single-crystal X-ray diffraction.

Polymers prepared through an "ATRP polymerization-esterification" strategy for dual temperature- and reduction-induced paclitaxel delivery.

Clinically, the nanotherapy of tumors has been limited by the drug content, efficiency of targeted release, and bioavailability. In this study, we fabricated an amphiphilic block polymer, poly(2-methacryloyloxyethyl thiocticcarboxylate)--poly(-isopropylacrylamide) (PMAOETC--PNIPAM), using an "ATRP polymerization-esterification" strategy for paclitaxel (PTX) delivery. The hydrophobic drug paclitaxel was encapsulated based on hydrogen bond interactions between PTX and the PMAOETC and PNIPAM blocks, together with hydrophobic interactions between PTX and PMAOETC segments, affording PTX-laden polymer micelles with ∼30% drug loading content.

[Virtual screen of effective AChE inhibitory constituents from Glycyrrhizae Radix et Rhizoma based on pharmacophore and molecular docking].

This research is to predict anti-Alzheimer's disease active constituents on the target of acetylcholinesterase(AChE) from Glycyrrhizae Radix et Rhizoma with the help of pharmacophore and molecular docking. AChE ligand-based pharmacophore model was set up and the molecular library of the constituents from Glycyrrhizae Radix et Rhizoma were established by collecting literature. Then the constituents from Glycyrrhizae Radix et Rhizoma were screen for the potential AChE inhibitory potency in silico through matching with the best pharmacophore model.

Study of the thermal decomposition mechanism of FOX-7 by molecular dynamics simulation and online photoionization mass spectrometry.

The thermal decomposition mechanism of energetic materials is important for analyzing the combustion mechanisms of propellants and evaluating the safety of propellants during transport and storage. 1,1-Diamino-2,2-dinitroethylene (FOX-7) is an important insensitive energetic material that can be used as an oxidizer in propellants. However, the initial decomposition mechanism of FOX-7 is not clear to date.

Synthesis and properties of a temperature-sensitive hydrogel based on physical crosslinking stereocomplexation of PLLA-PDLA.

A synthetic route to amphiphilic conetwork (APCN) gels was developed and involved (1) a ring-opening polymerization (ROP) synthesis of the macromonomer HEMA-PLLA/PDLA, and (2) a radical polymerization of a stereocomplex of the synthesized macromonomers with P(MEOMA--OEGMA) to form the APCN gels. The structure of the gel was successfully verified using X-ray diffraction. Thermal analysis and differential scanning calorimetry data showed that the thermal behaviors of the gels were greatly improved compared with that of polylactic acid (PLA).

Conductive Metal-Organic Frameworks with Extra Metallic Sites as an Efficient Electrocatalyst for the Hydrogen Evolution Reaction.

The 2D conductive metal-organic frameworks (MOFs) are expected to be an ideal electrocatalyst due to their high utilization of metal atoms. Exploring a new conjugated ligand with extra active metallic center can further boost the structural advantages of conductive MOFs. In this work, hexaiminohexaazatrinaphthalene (HAHATN) is employed as a conjugated ligand to construct bimetallic sited conductive MOFs (M2(M1∙HAHATN)) with an extra M-N moiety.

Effects of ultrasound irradiation on the properties of apricot kernels during accelerated debitterizing.

In this paper, studies were conducted to investigate the effects of ultrasonically accelerated debitterizing on the physicochemical properties of apricot kernels, such as color, texture, oil content, protein characteristics and amino acids, with UV-Vis spectroscopy, synchronous fluorescence spectroscopy, circular dichroism, electrophoresis, environmental scanning electron microscopy, and thermal property analysis. The results indicate that the novel debitterizing technique has insignificant influences on the oil and protein contents of apricot kernels; meanwhile, the color, texture and activity of beta-glucosidase were substantially improved, greatly contributing to the quality modification and shortening the debitterizing time. In addition, ultrasound greatly influenced the amino acid contents and compositions, the fluorescence spectra and the thermal properties of the apricot kernel proteins.

Detection of carboxylesterase by a novel hydrosoluble near-infrared fluorescence probe.

A novel hydrosoluble near-infrared fluorescence off-on probe has been developed for detecting carboxylesterase activity. The probe was designed by introducing (4-acetoxybenzyl)oxy as a quenching and recognizing moiety to the decomposed product of IR-783, which exhibits excellent near-infrared fluorescence features and good water solubility. The responding mechanism of novel probe 1 to carboxylesterase was investigated.

Study on the thermal decomposition mechanism of graphene oxide functionalized with triaminoguanidine (GO-TAG) by molecular reactive dynamics and experiments.

Graphene oxide (GO) has a catalytic effect on the thermal decomposition of energetic materials above the melting point. To further enhance the catalytic activity of GO, it has been functionalized with the high nitrogen ligand triaminoguanidine (TAG). However, theoretical studies on the reactivity of functionalized GO (, GO-TAG) have not been carried out.

Three hierarchical porous magnesium borate microspheres: a serial preparation strategy, growth mechanism and excellent adsorption behavior for Congo red.

The 3D hierarchical porous 7MgO·2BO·7HO (MBH) microspheres were prepared by a phase transformation of chloropinnoite firstly, and anhydrous α-3MgO·BO (MBA) microspheres were obtained by thermal conversion of 7MgO·2BO·7HO, and then β-3MgO·BO (MBB) microspheres were obtained by phase conversion of α-3MgO·BO. All samples were characterized by XRD, FT-IR, TG and SEM. The microsphere nanostructures with a hierarchical porous structure were assembled by nanosheets with a thickness of 20-30 nm, and the growth mechanisms were also proposed.

A straightforward chemical approach for excellent InS electron transport layer for high-efficiency perovskite solar cells.

Perovskite solar cells (PSCs) have attracted significant attention in recent years owing to some of their advantages: high-efficiency, low cost and ease of fabrication. In perovskite photovoltaic devices, charge transport layers play a vital role for selectively extracting and transporting photo-generated electrons and holes to opposite electrodes. Therefore, it is very important to prepare high-quality charge transport layers using simple processes at low cost.

Facile preparation of partially reduced graphite oxide nanosheets as a binder-free electrode for supercapacitors.

Preparation of graphene (GR) based electrode materials with excellent capacitive properties is of great importance to supercapacitors. Herein, we report a facile approach to prepare partially reduced graphite oxide (PRG) nanosheets by reducing graphite oxide (GO) using commercial CuO powder as a reduction agent, moreover, we demonstrate that the PRG nanosheets can act as building blocks for assembling hydrogels (PRGH) and flexible film (PRGF). The obtained PRGH and PRGF can be directly used as binder-free electrodes for supercapacitors and give high specific capacitance (292 and 273 F g at a current density of 0.