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Preview: Chinese Journal of Chemistry

Chinese Journal of Chemistry



Wiley Online Library : Chinese Journal of Chemistry



Published: 2017-08-01T00:00:00-05:00

 



A Novel BODIPY-Based Low-Band-Gap Small-Molecule Acceptor for Efficient Non-fullerene Polymer Solar Cells

2017-09-20T07:35:38.376581-05:00

We report herein an efficient A1-C≡C-A2-C≡C-A1 type small-molecule BODIPY acceptor (A1=BODIPY and A2=diketopyrrolopyrrole (DPP)) by following the A-to-A excited electron delocalization via the BODIPY meso-position, the inherent directionality for the excited electron delocalization. The lowest unoccupied molecular orbital (LUMO) delocalizes across over whole the two flanking A1 and the central A2, and the highest occupied molecular orbital (HOMO) localizes dominantly on the -C≡C-DPP-C≡C- segment. The excited electron upon light excitation of the DPP segment delocalizes over both the BODIPY and DPP segments. The acceptor in chloroform shows an unprecedented plateau-like broad absorption between 550 to 700 nm with a large FWHM value of 195 nm. Upon transition into solid film, the acceptor shows absorption in the whole near ultraviolet-visible-near infrared wavelength region (300-830 nm) with a low band gap of 1.5 eV and a maximum absorptivity of 0.85×105 cm-1. Introduction of the ethynyl spacer between the A1 and A2 and the close BODIPY-to-DPP LUMO energy levels are crucial for the excited π−electron delocalization across over whole the conjugation backbone. A power conversion efficiency of 6.60% was obtained from the ternary nonfullerene solar cell with PTB7-Th:p-DTS(FBTTh2)2 (0.5:0.5) as the donor materials, which is the highest value among the non-fullerene organic solar cells with BODIPY as the electron acceptor material.



Rapid detection of serum procalcitonin by immunochromatograghy technology based on freeze-dried up-convertion nanoparticles/ antibody conjugates

2017-09-19T04:51:07.532763-05:00

Procalcitonin (PCT) is a sensitive and specific biomarker for sepsis diagnosis and widely used as a biomarker to improve the diagnosis of bacterial infections and to guide the antibiotic therapy. In our work, an improved up-converting nanoparticle (UCP) technology based on the immunochromatographic assay (UPT-ICA) was developed for rapid and quantitative detection of PCT. In order to further improve the accuracy, sensitivity and stability of the assay on the basis of our previous study, the UCP coupling with monoclonal antibody of PCT (UCP-Ab1) was freeze-dried under certain conditions. And the detections of PCT levels with UCP-Ab1 conjugates before and after freeze-drying were evaluated. The results shown that, compared to the UCP-Ab1 conjugates without freeze-drying, the detection sensitivity of freeze-dried UCP-Ab1 is slightly improved, having a lower immunochromatogragh background and better stability. This improved method can provide a rapid, accurate, and relatively easy way for the clinical detection of PCT. Copyright © 2017 John Wiley & Sons, Ltd.



Recent Developments in Azide-Free Synthesis of 1,2,3-Triazoles

2017-09-17T23:35:22.445919-05:00

1,2,3-Triazoles, as one of the most significant nitrogen-containing heterocycles due to their extensive use in biology, material science and organic synthesis, have attained enormous interest. 1,2,3-Triazoles are commonly synthesized by metal-catalyzed azide–alkyne cycloaddition and organocatalytic azide–carbonyl cycloaddition, which indispensably employ the toxic and potentially explosive azides. The azide-free synthetic approaches provide a powerful and straightforward alternative to the assembly of diverse 1,2,3-triazoles without the use of azides. In this review, we summarize the recent development of the construction of 1,2,3-triazoles under azide-free conditions.



Recent Advances and Perspectives of Transition Metal-Catalyzed Asymmetric Fluorination Reactions

2017-08-31T08:15:32.879368-05:00

Owing to the high electronegativity and small size of a fluorine atom, incorporation of fluorine or fluorine-containing moieties can dramatically alter physicochemical properties, such as lipophilicity, metabolic stability and bioavailability.1



Progress on Li3VO4 as a Promising Anode Material for Li-ion Batteries

2017-08-30T04:51:20.55229-05:00

Vanadium oxide Li3VO4 has attracted much attention as anode material for Li-ion batteries in recent years since it has a low and safe redox potential (vs. Li metal), high specific capacity and its cost is low. However, the poor electronic conductivity and initial low coulombic efficiency limit its practical application. In this mini-review, the state-of-the-art results associated with Li3VO4 are summarized including structure, lithium insertion mechanism, preparation, modification, and electrochemical properties. Finally, the challenges and prospects are also discussed.



Reoxidation of Transition-metal Catalysts with O2

2017-09-11T10:41:26.735834-05:00

Transition-metal catalyzed oxidation reactions are central components of organic chemistry. On behalf of green and sustainable chemistry, molecular oxygen (O2) has been considered as an ideal oxidant due to its natural, inexpensive, and environmentally friendly characters, and therefore offers attractive academic and industrial prospects. In recent years, some powerful organic oxidation methods have been continuously developed. Among them, the use of molecular oxygen (O2) as a green and sustainable oxidant has attracted considerable attentions. However, the development of new transition metal-catalyzed protocols using O2 as an ideal oxidant is highly desirable but very challenging because of the low standard electrode potential of O2 to reoxidize the transition-metal catalysts. In this Account, we highlight some of our progress toward the use of transition-metal catalyzed aerobic oxidation reactions. Through the careful selection of ligand and the acidic additives, we have successfully realized the reoxidation of Cu, Pd, Mn, Fe, Ru, Rh, and bimetallic catalysts under O2 or air atmosphere (1 atm) for the oxidative coupling, oxygenation reactions, oxidative C-H/C-C bond cleavage, oxidative annulation, and olefins difunctionalization reactions. Most of the reactions can tolerate a range of functional groups. These methods provide new strategies for the green synthesis of alkynes, (α-keto)amides/esters, ketones/diones, O/N-heterocycles, β-azido alcohols, and nitriles. The high efficiency, low cost, and simple operation under air make these methodologies very attractive and practical. We will also discuss the mechanisms of these reactions which might be useful to promote the new type of aerobic oxidative reaction design. In this Account we highlight some of our progress on the aerobic oxidation approaches including oxidative couplings, oxygenation reactions, oxidative C-H/C-C bond functionalizations, oxidative annulations, in which the transition-metal catalysts were reoxidized by O2.



Enhanced Photocurrent Generation of Graphene/Au@ZnO Honeycomb Film

2017-09-06T23:45:54.38352-05:00

A bio-inspired graphene/Au@ZnO photoelectrode has been prepared via breath figure method, in which Au@ZnO nanospheres were uniformly distributed in the whole honeycomb film. The size of the honeycomb holes effects the light using efficiency. The honeycomb film with smaller holes in more ordered array shows better antireflective property. All the formed graphene/Au@ZnO honeycomb photoelectrodes show a fast, stable, and reversible response of photocurrent accompanied by each switch-on and switch-off event. Au@ZnO-modified graphene honeycomb film can combine the advantages of increased light harvesting provided by honeycomb structure, efficient charge separation from Au nanoparticles (NPs), and efficient electron transfer provided by graphene. Au@ZnO- modified graphene honeycomb film shows a two-fold increase of photocurrent generation than ZnO-modified graphene honeycomb film and a three-fold increase of photocurrent generation than Au@ZnO-modified graphene smooth film, respectively. The rational design and engineering of multi components with different functions in a hybrid bio-inspired structure hold great promise for further efficient solar energy conversion devices. A bio-inspired graphene/Au@ZnO honeycomb film with enhanced photocurrent generation has been synthesized by breath figure method.



Asymmetric Synthesis of 3-Allyloxindoles and 3-Allenyloxindoles by Scandium(III)-Catalyzed Claisen Rearrangement Reactions

2017-09-06T10:41:47.291638-05:00

Scandium-catalyzed asymmetric Claisen rearrangement reactions of 2-allyloxyindoles and 2-propargyloxyindoles provide a novel approach to diverse 3-allyloxindoles and 3-allenyloxindoles in excellent yields (up to 99%) and enantioselectivity (up to 99% ee) under mild reaction conditions. The scandium catalyst was derived from Sc(OTf)3 and Pybox ligand.



Arylhydrazones Derivatives Containing a Benzothiazole Moiety, Efficient Ligands in the Palladium-Catalyzed Mizoroki–Heck and Suzuki–Miyaura Cross-coupling Reactions under IR Irradiation

2017-09-05T04:42:32.744707-05:00

A simple arylhydrazone containing the benzothiazole moiety which may be used as an efficient ligand in the palladium-catalyzed Mizoroki–Heck and Suzuki–Miyaura cross-coupling reactions, under infrared irradiation as an alternative source of energy, is presented. The reactions proceeded with extremely high efficiency under mild conditions and produced very good yields. Simple arylhydrazones 1 and 2 containing a benzothiazole moiety are used as efficient ligands in the palladium-catalyzed Mizoroki–Heck and Suzuki–Miyaura cross-coupling reactions under infrared irradiation as an alternative source of energy.



A Three-dimensional Non-fullerene Small Molecule Acceptor for Solution-processed Organic Solar Cells

2017-09-05T04:15:46.582928-05:00

An acceptor-donor-acceptor (A-D-A) three-dimensional (3D) small molecule acceptor (SFTTIC), using spirobifluorene as the core unit linking with four thieno[3,2-b]thiophenes (TT) and end-capped with 2-(3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (INCN) was developed for solution processed organic solar cells. SFTTIC has a high absorption coefficient up to 3.12 × 105 mol−1•cm−1, good thermal stability and appropriate energy levels. The optimized power conversion efficiency (PCE) of 5.66% and 4.65% was achieved for the devices with PBDB-T:SFTTIC and PTB7-Th:SFTTIC, respectively.



Capacitive Properties of the Binder-Free Electrode Prepared from Carbon Derived from Cotton and Reduced Graphene Oxide

2017-09-03T23:50:41.676782-05:00

The binder-free composite films of reduced graphene oxide (rGO) and activated carbon derived from cotton (aCFC) have been fabricated and used as electrodes for electrochemical capacitors (ECs) to avoid the decrease of capacitive performance in traditional process caused by the additional binder. The optimal aCFC is prepared at 850 °C when the mass ratio of carbon and potassium hydroxide is 1 to 4. The optimal composite film prepared from the mass ratio of aCFC/GO=2/1 exhibits porous structure, and has a specific surface area of 849.6 m2•g−1 and a total pore volume of 0.61 mL•g−1. Based on the two-electrode system testing in 6.0 mol/L KOH electrolyte, the optimal composite has specific capacitance of about 202 F•g−1, 374 mF•cm−2 and 116 F•cm−3 in terms of mass, area and volume, and shows excellent rate capability and good cyclic stability (91.7% retention of the initial capacitance after 5000 cycles). Furthermore, the assembled solid-state ECs by using KOH/polyvinyl alcohol as electrolyte show good mechanical stability and capacitive performances after repeated bending cycles. It is proved that this method is effective to fabricate binder-free electrodes for ECs and will open up a novel route for the reuse of waste cotton. The binder-free composite films of reduced grapheme oxide (rGO) and activated carbon derived from cotton (aCFC) have been fabricated. The optimal composite films aCFCG-2 exhibits porous structure and has a larger specific surface area, a total pore volume, large specific capacitance, and good cyclic stability. The assembled solid-state ECs show good mechanical stability and capacitive performances after repeated bending cycles.



Three New Chromone Derivatives Produced by Phomopsis sp. HNY29-2B from Acanthus ilicifolius Linn.

2017-09-01T06:36:11.094626-05:00

Three new chromone derivatives, phomochromenones A-C (1–3), and one known chaetocyclinone B (4) were obtained from the cultures of Phomopsis sp. HNY29-2B isolated from the mangrove Acanthus ilicifolius Linn., which was collected from the South China Sea. Their structures were determined by the analysis of 1D NMR and 2D NMR as well as mass spectroscopic data. The absolute configurations of 1 and 2 were assigned by quantum chemical calculations of the electronic circular dichroism (ECD) spectra. Compound 3 is the third example of alkaloids possessing the unique chromeno [3,2-c] pyridine nucleus. In the bioactivity assay, compound 4 showed cytotoxicity against human prostate cancer cell lines (PC-3 and DU145 cells) with the IC50 values of 8.13 and 3.59 µmol/L, respectively. This paper presents a general overview of three new compounds (1–3), and one known chaetocyclinone B (4) isolated from Phomopsis sp. HNY29-2B. Their structures were determined by 1D NMR and 2D NMR and mass spectrum.



Macrocyclic-ligand Induced Synthesis of Aryl Ethynides with Divergent Silver(I) Clusters

2017-08-24T09:39:32.202367-05:00

Two structurally characterized metal-cluster-centered supramolecular architectures named [Ag8(1,2-(C ≡ C)2-C6H4)(Py[6])(CF3CO2)6] · 2.5MeOH (1) and [Ag12(1,2,4,5-(C ≡ C)4C6H2)(Py[6])2(CF3SO3)8]·4MeOH·3H2O (2) are synthesized through the interaction with a bowl-shaped macrocyclic ligand Py[6]. Particularly, two dissimilar silver(I) clusters are resulted in 2 within the structure under the influence of the macrocyclic ligand Py[6]. Such dissimilarity of the silver(I) cluster is also reflected on the structural and photophysical differences between 1 and 2. Two structural characterized metal-cluster-centered supramolecular architectures are synthesized through the interaction with a bowl-shaped macrocyclic ligand Py[6].



Hybridization: A Chemical Bonding Nature of Atoms

2017-08-24T09:39:28.348801-05:00

Both the bonding mode and geometry can serve as the chemical bonding nature of central cation, which is essentially determined by the atomic orbital-hybridization. In this work, we focus on the possible chemical bonding scheme of central cations on the basis of a quantitative analysis of electron domain of an atom. Starting from the hybridization of outer atomic orbitals that are occupied by valence electrons, we studied the possible orbital hybridization scheme of atoms in the periodic table and the corresponding coordination number as well as possible molecular geometries. According to distinct hybrid orbital sets, the chemical bonding of central cations can be classified into three typical types, resulting in the cations with a variety of coordination numbers ranging from 2 to 16. Owing to different hybridization modes, the highest coordination number of cations in IA and IIA groups is larger than that in IB-VIIIB groups, and the coordination number of lanthanide elements is most abundant. We also selected NaNO3, Fe(NO3)3•9H2O, Zn(NO3)2•6H2O, Y(NO3)3•3H2O, and La(NO3)3•6H2O as examples to confirm the direct relationship between chemical bonding characteristics and orbital hybrid set by IR spectra. The present study opens the door to reveal the chemical bonding nature of atoms on the basis of hybridization and will provide theoretical guides in structural design at an atomic level.



Two New C19-Diterpenoid Alkaloids with Anti-inflammatory Activity from Aconitum iochanicum

2017-08-01T07:55:35.851288-05:00

Two new C19-diterpenoid alkaloids, 7,8-epoxy-franchetine (1) and N(19)-en-austroconitine A (2), were isolated from Aconitum iochanicum. Compound 1 was a new C19-diterpenoid alkaloid with a 7,8-epoxy unit. Their structures were elucidated by comprehensive spectroscopic analyses including UV, IR, MS, 1D and 2D NMR. Biological activity tests indicated that two new compounds exhibited inhibitory activity against nitric oxide (NO) production in LPS-activated RAW264.7 macrophages. Compared with positive control, the two new compounds showed weak anti-inflammatory effects with the inhibition rate of 27.3% and 29.2%, respectively. Two new C19-diterpenoid alkaloids, 7,8-epoxy-franchetine (1) and N(19)-en-austroconitine A (2), were isolated from Aconitum iochanicum. They showed weak effects with the inhibition rate of 27.3% and 29.2%, respectively, relative to positive control.



Copper-Promoted Conversion of Aromatic Amines into Trifluoromethylated Arenes: One-Pot Sandmeyer Trifluoromethylation

2017-08-01T06:04:23.645008-05:00

A simple copper-promoted one-pot Sandmeyer trifluoromethylation of aromatic amines with Langlois’ reagent has been demonstrated. The reaction is performed in mild reaction conditions under an air atmosphere with good substrate scope and functional group compatibility. It provides an alternative and straightforward synthetic approach to access a variety of trifluoromethylated arenes. A simple copper-promoted one-pot trifluoromethylation of aromatic amines with Langlois’ reagent has been developed in mild reaction conditions under an air atmosphere. The present transformation, possessing good substrate scope and functional group compatibility, provides an alternative and attractive approach to access a variety of trifluoromethylated arenes, which are of broad interest in pharmaceuticals, agrochemicals and functional materials.



Facile Synthesis of Novel Perfluorocarbon-Modulated 4-Anilinoquinazoline Analogues

2017-08-01T06:01:46.317838-05:00

4-Anilinoquinazoline analogues stand out among many kinds of small molecules that inhibit the tyrosine kinase activities of epidermal growth factor receptor (EGFR), thus serving as significant molecular targets for anticancer drug design. Herein, a series of novel perfluorocarbon (PFC) modulated 4-anilinoquinazolines were designed and prepared straightforwardly by nucleophilic substitution reaction of various anilinoquinazolines and PFC-derived methanesulfonate. In the presence of base, the reaction proceeded smoothly to afford a wide range of 4-anilinoquinazolines with different substituents on aniline moiety in good to high yields. Furthermore, the PFC-modified analogues of gefitinib and erlotinib were also obtained in 93% and 90% respectively, which may have potential for developing new inhibitors of the epidermal growth factor receptor (EGFR) tyrosine kinase and fluorinated contrast agents (CA) for 19F MRI.



Enzyme-Triggered Fluorescence Turn-on: A Probe for Specifically Imaging Ovarian-Cancer-Related γ-Glutamyltranspeptidase

2017-08-01T05:59:27.893622-05:00

A fluorescent turn-on probe for specifically targeting γ-glutamyltranspeptidase (GGT) was designed and synthesized by integrating boron-dipyrromethene (BODIPY) as a chromophore and glutathione (GSH) as the GGT substrate. GGT-catalyzed the cleavage of the γ-glutamyl bond and generated the aromatic hydrocarbon transfer between the sulfur and the nitrogen atom in BODIPY, leading to distinct optical changes. Such specific responsiveness provides an easily distinguishable fluorescence signal to visualize the GGT activity in living cells and differentiate GGT-positive cancer cells from GGT-negative cells. GGT-triggered fluorescence turn-on was capable of differentiating GGT-positive cancer cells from GGT-negative cells.



An Effective Asphalt UV Blocking Material Based on Host-Guest Schiff Base/Layered Double Hydroxides

2017-08-01T05:46:46.870783-05:00

The development of asphalt-based UV blocking materials is important to extend the alphalt lifespan in road construction. In this work, we put forward that the fabrication of host-guest system can be an effective way to obtain UV blocking materials. Firstly, a new anionic Schiff base, N,N'-bis(salicylidine)-4,4'-diaminostilbene-2,2'-disulfonic acid (SDSD), has been synthesized, which was intercalated into Zn-Al-LDH by anion-exchange method. FT-IR and XRD illustrate the layered organic–inorganic composite, Zn-Al-SDSD-LDH, has been successfully synthesized with high crystallinity. Laser particle size analyzer, SEM and TEM show that particle size distributions of Zn-Al-SDSD-LDH is in the range 100–500 nm. UV–vis absorption spectra show that Zn-Al-SDSD-LDH has better UV absorption than the pristine Zn-Al-LDH and SDSD. Furthermore, the mixture of asphalt and 3 wt% Zn-Al-SDSD-LDH presents enhanced UV blocking property relative to the pristine asphalt after irradiating by UV spray accelerated weathering test. Therefore, this work not only develops a new type of host-guest Zn-Al-SDSD- LDH, but also confirms it can be an effective asphalt UV blocking material for practical application. N,N'-Bis(salicylidine)-4,4'-diaminostilbene-2,2'-disulfonic acid was intercalated into Zn-Al-LDH by anion-exchange method, which could serve as UV blocking material for asphalt.



Enhanced Electrochemical Performance of Ti-Doping Li1.15Ni0.47Sb0.38O2 as Lithium-excess Cathode for Lithium-ion Batteries

2017-07-26T11:39:46.270724-05:00

Recent success and application of the percolation theory have highlighted cation-disordered Li-rich oxides as high energy density cathode materials. Generally, this kind of cathode materials suffer from low cycling stability and rate performance. Doped Ti4+ ions can improve the long-term cycling stability and rate performance of the Li-rich oxides materials with obvious capacity fading. The electrochemical performance in LixNi2−4x/3Sbx/3O2 can benefit a lot from the nanohighway, which is a kind of nanoscale 0-TM diffusion channels in the transition metal layer and provides low diffusion barrier pathways for the lithium diffusion. In this work, the doping effect of Ti on the structure and electrochemical properties in Li1.15Ni0.47Sb0.38O2 is studied. The Ti-stabilized Li1.15−xNi0.47TixSb0.38O2 (x=0, 0.01, 0.03 and 0.05) have been prepared by a solid-state method and the Li1.03Ni0.47Sb0.38Ti0.03O2 sample exhibits outstanding electrochemical performance with a larger reversible discharge capacity, better rate capability and cyclability. Synchrotron-based XANES, combined with ab initio calculations in the multiple-scattering framework, reveals the Ti ions have been doped into the Li-site in the lithium layer and formed a distortion TiO6 octahedron. This TiO6 local configuration in the lithium can keep the stability of nanohighway in the electrochemical process. In particular, the Li1.03Ni0.47Sb0.38Ti0.03O2 compound can deliver a discharge capacities 132 and 76 mAh/g at 0.2 and 5 C, respectivly. About 86% capacity retention occurs at 1 C rate after 500 cycles. This work suggests capacity fading in the oxide cathode materials can be suppressed to construct and stabilize the nanohighway. In this work, the doping effect of Ti on the structure and electrochemical properties of Li1.15Ni0.47Sb0.38O2 is studied. The Ti-stabilized Li1.15−4xNi0.47TixSb0.38O2 (x=0, 0.01, 0.03 and 0.05) have been prepared by a solid-state method and the Li1.03Ni0.47Sb0.38Ti0.03O2 sample exhibits outstanding electrochemical performance with a larger reversible discharge capacity, better rate capability and cyclability.



A 2D Metal-Organic Framework Based on 9-(Pyridin-4-yl)-9H-carbazole-3,6-dicarboxylic Acid: Synthesis, Structure and Properties

2017-07-26T11:35:01.907468-05:00

A metal-organic framework (MOF) formulated as [Cd2(μ3-L)2(DMF)4]•H2O (CdL) [H2L=9-(pyridin-4-yl)- 9H-carbazole-3,6-dicarboxylic acid, DMF=N,N-dimethylformamide] was synthesized under solvothermal condition. Crystal structural analysis reveals that CdL features the layered 2D framework with L2− ligands as 3-connected nodes. The compound CdL emits blue-violet light with the narrow emission peak and the emission maximum at 414 nm upon excitation at the maximum excitation wavelength of 340 nm. The compound CdL has a similar emission spectrum curve to the free H2L ligand that indicates the emission of compound CdL should be originated from the coordinated L2− ligands. A metal-organic framework based on 9-(pyridin-4-yl)-9H-carbazole-3,6-dicarboxylic acid (H2L) has been synthesized. It features the 2D framework and exhibits a narrow emission band with the peak at 414 nm.



Assembly of Preformed Gold Nanoparticles onto Thermoresponsive Poly(N-isopropylacrylamide)-Based Microgels on the Basis of Au-thiol Chemistry

2017-07-26T11:35:00.116499-05:00

The assembly of preformed gold nanoparticles (AuNPs) onto the thermoresponsive poly(N-isopropylacrylamide) (PNIPAM)-based microgels was achieved on the basis of the driving force of Au-thiol chemistry. The loading amount of AuNPs can be controlled by varying the ratio of AuNPs relative to PNIPAM-based microgels. The as-prepared PNIPAM/Au hybrid microgels showed well-defined reversible swelling/deswelling transition in response to temperature, which can be employed to tune the plasmonic property of hybrid microgels. As the temperature was increased, the position of localized surface plasmon resonance (LSPR) band red-shifted to some extent mainly due to the increase in the local refractive index around AuNPs. The assembly of preformed gold nanoparticles (AuNPs) onto the thermoresponsive poly(N-isopropylacrylamide) (PNIPAM)-based microgels was achieved on the basis of the driving force of Au-thiol chemistry instead of the traditional electrostatic attraction



Oxidative Rearrangement of Isatins with Arylamines Using H2O2 as Oxidant: A Facile Synthesis of Quinazoline-2,4-diones and Evaluation of Their Antibacterial Activity

2017-07-26T11:34:48.612196-05:00

A green and highly efficient synthetic method for the synthesis of quinazoline-2,4-diones with hydrogen peroxide as the terminal oxidant has been developed. The reaction features the mild reaction conditions, broad substrate scope, metal-free catalysts, and sole byproduct water. A plausible mechanism for this process was proposed. Moreover, an antibacterial activity study was performed to evaluate the antimicrobial activities towards two Gram-negative bacterial strains (Escherichia coli, and Klebsiella pneumonia) and two Gram-positive bacterial strains (Staphylococcus epidermidis, and Staphylococcus aureus) using the Broth microdilution method.



One-Pot Synthesis of 4-Aryl-NH-1,2,3-Triazoles through Three-Component Reaction of Aldehydes, Nitroalkanes and NaN3

2017-07-26T11:28:13.403725-05:00

A one-pot three-component reaction of aldehydes, nitroalkanes and NaN3 for the synthesis of NH-1,2,3-triazoles has been developed. The reaction provides a safe, efficient and step-economic approach for the synthesis of various NH-1,2,3-triazoles in good to excellent yields. A one-pot three-component reaction of aldehydes, nitroalkanes and NaN3 for the synthesis of NH-1,2,3-triazoles has been developed.



Improving Thermal and Flame Retardant Properties of Epoxy Resin with Organic NiFe-Layered Double Hydroxide-Carbon Nanotubes Hybrids

2017-07-26T11:27:56.844922-05:00

To improve the dispersion of carbon nanotubes (CNTs) and flame retardancy of layered double hydroxide (LDH) in epoxy resin (EP), organic nickel-iron layered double hydroxide (ONiFe-LDH-CNTs) hybrids were assembled through co-precipitation. These hybrids were further used as reinforcing filler in EP. EP/ONiFe-LDH-CNTs nanocomposites containing 4 wt% of ONiFe-LDH-CNTs with different ratios of ONiFe-LDH and CNTs were prepared by ultrasonic dispersion and program temperature curing. The structure and morphology of the obtained hybrids were characterized by different techniques. The dispersion of nanofillers in the EP matrix was observed by transmission electron microscopy (TEM). The results revealed a coexistence of exfoliated and intercalated ONiFe-LDH- CNTs in polymer matrix. Strong combination of the above nanofillers with the EP matrix provided an efficient thermal and flame retardant improvement for the nanocomposites. It showed that EP/ONiFe-LDH-CNTs nanocomposites exhibited superior flame retardant and thermal properties compared with EP. Such improved thermal properties could be attributed to the better homogeneous dispersion, stronger interfacial interaction, excellent charring performance of ONiFe-LDH and synergistic effect between ONiFe-LDH and CNTs. Organic nickel-iron layered double hydroxides (ONiFe-LDH) were assembled on carboxylated carbon nanotubes (CNTs) through co-precipitation method and characterized. EP/ONiFe-LDH-CNTs nanocomposites containing 4 wt% of ONiFe-LDH-CNTs with different ratios of ONiFe-LDH and CNTS were prepared by ultrasonic dispersion and program temperature curing method. Strong combination of the above nanofillers with the EP matrix provided an efficient thermal and flame retardant improvement for the resulting nanocomposites. It is showed that EP containing 4 wt% ONiFe-LDH-CNTs hybrid exhibited superior flame retardant and thermal properties compared with pure EP.



Gemini Surfactants Templated Mesoporous Silica Microparticles: from Solid to Hollow Mesoporous Spheres

2017-07-25T06:41:44.499216-05:00

We synthesized a series of mesoporous silica microparticles (MSs) using cationic gemini surfactants C14–2-n (n = 2, 6, 10, 14) as templates. The porous structures and pore size of these MSs can be tuned by varying the length of alkyl chain in gemini surfactant templates. These MSs showed effective doxorubicin (DOX) loading and a pH-responsive drug release characteristics. These results indicate that the MSs, especially the hollow mesoporous silica nanoparticles, have great potential for biomedical applications. Changing with the structures of gemini surfactant templates, the MSs showed different structures from solid to hollow mesoporous spheres with different pores.



Regioselective Synthesis of SCF3-Substituted 2,4-Diarylquinazoline Using AgSCF3 as Trifluoromethylthiolation Reagent

2017-07-25T06:35:27.337184-05:00

A facile and efficient route to 4-aryl-2-[2-(trifluoromethylthio) aryl]quinazoline derivatives through a tandem directed Rh-catalyzed C-H iodination and trifluoromethylthiolation is described. The reaction proceeded under mild reaction conditions, exhibited good functional group tolerance with a broad scope of substrate and excellent regioselectivity in good to excellent yields. A facile and efficient route to 4-aryl-2-[2-(trifluoromethylthio) aryl]quinazoline derivatives through a tandem directed Rh-catalyzed C-H iodination and trifluoromethylthiolation is described. This strategy provides an access to various structurally versatile trifluoromethylthiolated 2,4-diarylquinazolines with potentially useful biological and pharmaceutical activities.



MCM-41 Immobilized Acidic Functional Ionic Liquid and Chromium(III) Complexes Catalyzed Conversion of Hexose into 5-Hydroxymethylfurfural

2017-07-12T08:43:06.847377-05:00

The development of novel methods to obtain biofuels and chemicals from biomass has been an immediate issue in both academic and industrial communities. In this work, a series of novel catalysts were prepared and characterized by FT-IR, TGA, XRD, SEM, TEM, ICP-AES, NH3-TPD and BET, which were applied for the conversion of hexose to 5-hydroxymethylfurfural (HMF). The Cr(Salten)-MCM-41-[(CH2)3SO3HVIm]HSO4 catalyst was the most active catalyst, and a glucose conversion of 99.8% with 50.2% HMF yield was obtained at 140 °C for 4 h in dimethyl sulfoxide (DMSO). The effects of reaction temperature, reaction time, solvents and catalyst dosages were investigated in detail. MCM-41 immobilized acidic functional ionic liquid and chromium(III) Schiff base complexes as heterogeneous catalysts can be easily recovered by simple filter treatment, exhibiting excellent stability and activity towards hexose conversion. Thus the heterogeneous catalysts were environment-friendly for transforming biomass carbohydrates into fine chemicals. A heterogeneous catalyst was prepared by immobilizing the Schiff base chromium metal complex on the acidic ionic liquid modified MCM-41 and used in the conversion of hexose to HMF. A higher HMF yield was obtained when glucose was used as raw material.



Fluorescent Linear Supramolecular Polymer Based on Host-Guest Interactions

2017-07-12T08:35:30.321734-05:00

Construction of supramolecular polymers, in which functional monomer components are held together by noncovalent interactions, is considered as a promising design principle for functional materials. Linear fluorescent supramolecular polymer assembled on account of electrostatic attractions based host-guest interaction is synthesized and illustrated here. 1H NMR was involved to ensure the structure of guest and polymer, UV–vis and fluorescent spectra were recorded to be a readout signal to investigate the assemble process of polymer. TEM and AFM measurements were carried out to confirm the homogeneous nanometer-sized molecular assembly. It shows the way to be used as remote readout fluorescent functional material in the future. Construction of supramolecular polymers, in which functional monomer components are held together by noncovalent interactions, is considered as a promising design principle for functional materials. Linear fluorescent supramolecular polymer assembled on account of electrostatic attractions based host-guest interaction is synthesized and illustrated here.1H NMR was involved to ensure the structure of guest and polymer, UV–vis and fluorescent spectra were recorded to be a readout signal to investigate the assemble process of polymer. TEM and AFM measurements were carried out to confirm the homogeneous nanometer-sized molecular assembly. It shows the way to be used as remote readout fluorescent functional material in the future.



Copper-Catalysed Decarboxylative Trifluoromethylation of β-Ketoacids

2017-07-12T08:35:23.49672-05:00

An efficient method for Cu-catalyzed decarboxylative trifluoromethylation of β-ketoacids to achieve α-trifluoromethyl ketones was developed. A wide variety of synthetically useful α-trifluoromethyl ketones were obtained in modest to good yields under mild reaction conditions. The present method also exhibits good functional-group compatibility. An efficient method for Cu-catalyzed decarboxylative trifluoromethylation of β-ketoacids to achieve α-trifluoromethyl ketones was developed. A wide variety of synthetically useful α-trifluoromethyl ketones were obtained in modest to good yields under mild reaction conditions. The present method also exhibits good functional-group compatibility.



Selective Insertion in Copolymerization of Ethylene and Styrene Catalyzed by Half-Titanocene System Bearing Ketimide Ligand: A Theoretical Study

2017-07-12T08:30:23.833897-05:00

The copolymerization of ethylene and styrene can be efficiently carried out by using Cp*TiCl2(N = CtBu2)/MAO (Cp*=η5-C5Me5) system, yielding the poly(ethylene-co-styrene)s with isolated styrene units. In order to investigate the reasons for formation of the structure, the mechanism of copolymerization, especially the selective insertion of ethylene and styrene, is studied in detail by density functional theory (DFT) method. At the initiation stage, insertion of ethylene is kinetically more favorable than insertion of styrene, and insertion of styrene kinetically and thermodynamically prefers 2,1-insertion. That is different from the conventional half-titanocene system, in which the 1,2-insertion is favorable. At chain propagation stage, the computational results suggest that the continuous insertion of styrene is hard to occur at room temperature due to the high free energy barriers (28.90 and 35.04 kcal/mol for 1,2-insertion, and 29.15 and 34.00 kcal/mol for 2,1-insertion) and thermodynamically unfavorable factors in two different conditions. That is mainly attributed to the steric hindrance between the coming styrene and chain-end styrene or ketimide ligand. The computational results are in good agreement with the experimental data.



Polydiacetylene-Tb3+ Nanosheets of Which Both the Color and the Fluorescence Can Be Reversibly Switched between Two Colors

2017-07-10T05:40:22.54808-05:00

Polydiacetylenes (PDAs), an organic layered compound, show a series of intriguing properties, such as thermochromism and fluorescence emission in the red-phase. However, their irreversible color change, and weak and single-color fluorescence emitted only from the red-phase PDAs, have limited their applications. Herein, we report double-reversible PDA-Tb3+ nanosheets of which both the color and the fluorescence can be reversibly switched between two colors. PDA-Tb3+ nanosheets have the nearly defect-free intercalated structure in which a layer of Tb3+ ions was intercalated in between each two PDA bilayers to tether almost all of the carboxyl groups at the end of the side chains of the PDA. When the PDA is in the blue phase, the PDA-Tb3+ nanosheets emit the green fluorescence of Tb3+ ions. When the PDA is in the red phase, the Tb3+ fluorescence disappears while the intrinsic red fluorescence of PDA is effectively enhanced through the fluorescence resonance energy transfer (FRET) process; the PDA-Tb3+ nanosheets emit stronger red fluorescence compared with the PDA in red phase. Moreover, the tethering of almost all of the carboxyl groups at the end of the side chains of the PDA endows the nanosheets with the double reversibility in both the color and fluorescence transitions. PDA-Tb3+ nanosheets with reversible color and fluorescence switching between two colors were realized by the intercalation of Tb3+ ions into layered PDA.



Carbon Tetrabromide/Triphenylphosphine-Activated Beckmann Rearrangement of Ketoximes for Synthesis of Amides

2017-07-10T05:21:49.777831-05:00

An efficient Beckmann rearrangement of ketoximes was developed using carbon tetrabromide/triphenylphosphine as an organocatalyst without addition of any acids or metals. The reaction showed good functional group tolerance and gave various amides in moderate to good yields.



Motions of Trimethylphosphine Oxide in Carbon Nanotubes as Revealed by Solid-state NMR

2017-07-10T05:16:24.743711-05:00

Trimethylphosphine (TMP) has been adsorbed in carbon nanotubes and oxidized to trimethylphosphine oxide (TMPO). 31P spin–lattice relaxation T1 measurements at temperatures from 203 to 333 K have been employed to investigate the motions of TMPO. The 31P T1 is found to be monoexponential and isotropic. The activation energy is measured as 4.4 ± 0.3 kcal•mol−1, which is comparable to that of TMP adsorbed on Lewis acid sites in zeolites. The Arrhenius activation energy for the motion of the phosphorus-proton vector of trimethylphosphine oxide adsorbed in carbon nanotubes was measured as 4.4 ± 0.3 kcal•mol−1 by using solid-state NMR.



Sesquiterpenoids of Illicium jiadifengpi and Their Effects on NGF-induced Neurite Outgrowth in PC12 Cells

2017-07-07T10:55:23.887334-05:00

Two new compounds, jiadifenlactone acid monomethyl ester (1) and jiadifenin (3), and five known compounds were isolated from the fruits of I. jiadifengpi. Their structures were determined using spectroscopic techniques, including 1D, 2D NMR and HR-ESI-MS experiments. The relative stereochemistry of jiadifenlactone acid monometheyl ester (1) was further confirmed by X-ray crystallographic data. All isolates were evaluated for their effects on nerve growth factor (NGF)-mediated neurite outgrowth in pheochromocytoma (PC12) cells and two compounds showed promoting effects. Two new compounds, jiadifenlactone acid monomethyl ester (1) and jiadifenin (3), and five known compounds were isolated from the fruits of I. jiadifengpi. Furthermore, the isolated compounds were evaluated for their effects on nerve growth factor (NGF)-mediated neurite outgrowth in pheochromocytoma (PC12) cells and two compounds showed promoting effects.



Dehydrogenation of Isobutane to Isobutene with Carbon Dioxide over SBA-15-Supported Chromia-Ceria Catalysts

2017-07-07T10:50:24.829731-05:00

A series of SBA-15-supported chromia-ceria catalysts with 3% Cr and 1%–5% Ce (3Cr-Ce/SBA) were prepared using an incipient wetness impregnation method. The catalysts were characterized by XRD, N2 adsorption, SEM, TEM-EDX, Raman spectroscopy, UV–vis spectroscopy, XPS and H2-TPR, and their catalytic performance for isobutane dehydrogenation with CO2 was tested. The addition of ceria to SBA-15-supported chromia improves the dispersion of chromium species. 3Cr-Ce/SBA catalysts are more active than SBA-15-supported chromia (3Cr/SBA), which is due to a higher concentration of Cr6+ species present on the former catalysts. The 3Cr-3Ce/SBA catalyst shows the highest activity, which gives 35.4% isobutane conversion and 89.6% isobutene selectivity at 570 °C after 10 min of the reaction. The incorporation of ceria to SBA-15-supported chromia obviously improves the catalytic activity for the dehydrogenation of isobutane with CO2 due to the enhanced number of Cr6+ species.



PdCl2(Ph3P)2/Salicylaldimine Catalyzed Diarylation of Anilines with Unactivated Aryl Chlorides

2017-07-07T10:40:48.7241-05:00

Triphenylphosphine and salicylaldimine could be used as a mixed ligand system to obtain a high catalytic activity for palladium catalyzed diarylation of primary anilines with unactivated aryl chlorides by the synergistic effect of ligands. The activity and selectivity of the catalytic system could be improved by modifying the structure of salicylaldimine. In refluxing o-xylene, PdCl2(Ph3P)2 with 2,5-ditrifluoromethyl N-phenylsalicylaldimine as a coligand shows high efficiency for the diarylation of various anilines. The catalytic system shows good toleration for the steric hindrance of the substrates. The facile catalytic system works as well on the multiple arylation of 1,1′-biphenyl- 4,4′-diamine with aryl chlorides to afford N,N,N′,N′-tetraaryl-1,1′-biphenyl-4,4′-diamines which are important intermediates of organic light emitting diode (OLED) hole transport materials.



Asymmetric Synthesis of Chiral Trifluoromethyl Containing Heterocyclic Amino Acids

2017-07-07T10:35:27.137336-05:00

An operationally convenient, asymmetric synthesis of chiral trifluoromethyl containing heterocyclic amino acids has been developed via Michael addition reaction of chiral equivalent of Ni(II)-complex of glycine and β-trifluoromethylated-α,β-unsaturated ketones. The simplicity of the experimental procedures and high stereochemical outcome of the presented method render these heterocyclic amino acids readily available for systematic medicinal chemistry studies and de novo peptide design.



Highly Efficient Photocatalytic Remediation of Simulated Polycyclic Aromatic Hydrocarbons (PAHs) Contaminated Wastewater under Visible Light Irradiation by Graphene Oxide Enwrapped Ag3PO4 Composite.

2017-07-07T10:30:25.894824-05:00

Effective removal of polycyclic aromatic hydrocarbons (PAHs) from wastewater before their discharge into the environment is an ever pressing requirement. In this study, for the first time, simulated PAHs contaminated wastewater was photocatalytically remediated with graphene oxide (GO) enwrapped silver phosphate as visible light-driven photocatalysts. The GO/Ag3PO4 photocatalysts exhibited superior photocatalytic activity and stability compared with pure Ag3PO4, g-C3N4 and TiO2 (P25). The degradation efficiency of naphthalene, phenanthrene and pyrene could reach 49.7%, 100.0% and 77.9%, rspectively within 5 min irradiation. The apparent rate constants of photocatalytic degradation of 3 wt% GO/Ag3PO4 composite photocatalyst were 0.14, 1.21 and 2.46 min−1 for naphthalene, phenanthrene and pyrene, respectively. They were about 1.8, 1.5 and 2.0 times higher than that of pure Ag3PO4, and much higher than that of g-C3N4 and TiO2. Meanwhile, the efficiencies of 44.6%, 95.2% and 83.8% were achieved for naphthalene, phenanthrene and pyrene degradation even after 5 times of recycling in the GO/Ag3PO4-PAHs photocatalysis system. Reactive species of ∙O2− and h+ were considered as the main participants for oxidizing naphthalene, phenanthrene and pyrene. We demonstrated for the first time that GO/Ag3PO4 composite exhibited excellent photocatalytic degradability and reusability for simulated PAHs contaminated wastewater under visible light irradiation.



Advances of Metal-Organic Frameworks in Energy and Environmental Applications

2017-07-05T04:40:29.127427-05:00

Nowadays, energy shortage and environmental pollution issues are increasingly severe and urgent to be solved. The effective storage and use of environmentally friendly fuels and removal of harmful gases from the environment are great challenges and of great importance both for the environment protection and for human health. Porous metal-organic frameworks (MOFs) are highly ordered crystalline materials formed by the self-assembly process of metal ions and organic ligands. Their good features such as ultrahigh porosity, large surface area, structural diversity and functionalities make them promising candidates for applications in energy and environmental fields. MOF thin films and MOF composites have also been investigated to further enhance the properties and introduce new functionalities. This review provides an overview of the synthesis methods of pristine MOFs, MOF thin films and MOF composites, and significant advances of MOFs in energy and environment applications such as energy storage (H2, CH4), CO2 capture and separation, adsorption removal and sensing of harmful gases in the environment. Metal-organic frameworks (MOFs) have aroused great attention over decades owing to their features such as ultrahigh porosity, large surface area, structural diversity and functionalities which make them promising candidates for diversified applications. This microreview focuses the emphasize on their applications in energy and environmental fields such as energy storage (H2 and CH4), CO2 capture and separation, adsorption removal and sensing of harmful gases in the environment, and also depicts some challenges and perspectives.



Synthesis of 2-Amino-1,3,4-oxadiazoles through Elemental Sulfur Promoted Cyclization of Hydrazides with Isocyanides

2017-07-05T04:35:30.096865-05:00

A novel sulfur-promoted cyclization of hydrazides and isonitriles to produce 1,3,4-oxadiazole has been developed. The method is operationally simple and compatible with a wide scope of substrates and various 2-amino- 1,3,4-oxadiazoles are efficiently obtained in good yields. A novel sulfur-promoted cyclization of hydrazides and isonitriles to produce 1,3,4-oxadiazole has been developed. The method is operationally simple and compatible with a wide scope of substrates and various 2-amino-1,3,4-oxadiazoles are efficiently obtained in good yields.



Synthesis of Quinoline and 1,2,3,4-Tetrahydroquinoline Derivatives from Substituted o-Nitrotoluenes via Cesium-promoted [2 + 4] Cycloaddition

2017-07-05T04:35:24.729555-05:00

An atom economical highly efficient method has been developed for the synthesis of quinoline and 1,2,3,4-tetrahydroquinoline derivatives from o-nitrotoluenes bearing electron-withdrawing groups and olefins (acrylic esters, acrylonitriles, and methyl acrylates) via a base-catalyzed [2 + 4] cycloaddition. This simple, rapid, and environment- friendly method provides a practical pathway for the synthesis of quinoline and 1,2,3,4-tetrahydroquinoline derivatives. The starting materials are readily available and 37 products were obtained in good to excellent yields. A one-pot procedure for the preparation of quinoline and 1,2,3,4-tetrahydroquinoline derivatives from o-nitrotoluenes bearing electron-withdrawing groups and olefins (acrylic esters, acrylonitriles, and methyl acrylates) via a base-catalyzed [2 + 4] cycloadditions was discribed.



Synthesis of Trisubstituted Isoxazoles from Nitroenamines and Aromatic Aldehydes

2017-07-05T04:35:21.663032-05:00

A novel approach for the synthesis of trisubstituted isoxazoles from nitroenamines and aromatic aldehydes is developed. L-Proline/potassium carbonate system was employed to promote this process. The reaction underwent nucleophilic attack of nitroenamines to aromatic aldehydes, intramolecular denitration, tautomerization and elimination of H2O to furnish the target compounds. A novel approach for the synthesis of trisubstituted isoxazoles from nitroenamines and aromatic aldehydes is developed. L-Proline/K2CO3 system was employed to promote this process. The reaction underwent nucleophilic attack of nitroenamines to aromatic aldehydes, intramolecular denitration, tautomerization and elimination of H2O to furnish the target compounds.



Flexible Three-Dimensional Graphene Hydrogels with Superior Conductivity and Excellent Electrochemical Performance for Supercapacitor Electrodes

2017-07-03T10:50:21.882925-05:00

Three-dimensional porous graphene hydrogels have been prepared by a green and facile but very efficient approach using glucose as an assistant. Based on a one-step hydrothermal reaction with optimal experimental conditions such as the reaction time and temperature, the graphene hydrogels exhibit a superior electrical conductivity (95.3 S/m) and can be used as supercapacitor electrode without any binder or conducting additives but showing a high specific capacitance of 384.6 F/g at a current density of 1 A/g. The results show that addition of glucose can not only greatly decrease the reaction temperature but also shorten the reaction time. The superior performance of the three-dimensional porous graphene hydrogels as electrode for supercapacitor suggests its promising potentials in the field of energy storage devices. Flexible three-dimensional graphene hydrogels (GHs-Glu) have been prepared via a one-step hydrothermal reaction and shown an excellent electrochemical performance for supercapacitor electrode.



Effect of Brønsted/Lewis Acid Ratio on Conversion of Sugars to 5-Hydroxymethylfurfural over Mesoporous Nb and Nb-W Oxides

2017-07-03T10:45:33.606567-05:00

A series of mesoporous Nb and Nb-W oxides were employed as highly active solid acid catalysts for the conversion of glucose to 5-hydroxymethylfurfural (HMF). The results of solid state 31P MAS NMR spectroscopy with adsorbed trimethylphosphine as probe molecule show that the addition of W in niobium oxide increases the number of Brønsted acid sites and decreases the number of Lewis acid sites. The catalytic performance for Nb-W oxides varied with the ratio of Brønsted to Lewis acid sites and high glucose conversion was observed over Nb5W5 and Nb7W3 oxides with high ratios of Brønsted to Lewis acid sites. All Nb-W oxides show a relatively high selectivity of HMF, whereas no HMF forms over sulfuric acid due to its pure Brønsted acidity. The results indicate fast isomerization of glucose to fructose over Lewis acid sites followed by dehydration of fructose to HMF over Brønsted acid sites. Moreover, comparing to the reaction occurred in aqueous media, the 2-butanol/H2O system enhances the HMF selectivity and stabilizes the activity of the catalysts which gives the highest HMF selectivity of 52% over Nb7W3 oxide. The 2-butanol/H2O catalytic system can also be employed in conversion of sucrose, achieving HMF selectivity of 46% over Nb5W5 oxide. 52% HMF selectivity with 100% glucose conversion achieves over Nb7W3 oxide in 2-butanol/H2O system which stabilizes the catalyst activity.



Tailoring Excited State Properties and Energy Levels Arrangement via Subtle Structural Design on D-π-A Materials

2017-07-03T10:45:30.089435-05:00

The donor-π-conjugated-acceptor (D-π-A) structure is an important design for the luminescent materials because of its diversity in the selections of donor, π-bridge and acceptor groups. Herein, we demonstrate two examples of D-π-A structures capable to finely modulate the excited state properties and arrangement of energy levels, TPA-AN-BP and CZP-AN-BP, which possess the same acceptor and π-bridge but different donor. The investigation of their photophysical properties and DFT calculation revealed that the D-π-A structure with proper donor, π-bridge and acceptor can result in separation of frontier molecular orbitals on the corresponding donor and acceptor with an obvious overlap on the π-bridge, resulting in a hybridized local and charge-transfer (HLCT) excited state with high photoluminescent (PL) efficiencies. Meanwhile, their singlet and triplet states are arranged on corresponding moieties with large energy gap between T2 and T1, and a small energy gap between S1 and T2, which favor the reverse intersystem crossing (RISC) from high-lying triplet levels to singlet levels. As a result, the sky-blue emission non-doped OLED based on the TPA-AN-BP reached maximum external quantum efficiency (EQE) of 4.39% and a high exciton utilization efficiency (EUE) of 77%. This study demonstrates a new strategy to construct highly efficient OLED materials. The D-π-A structure with proper donor, π-bridge and acceptor can result in high photoluminescent efficiencies and high exciton utilization efficiency.



Rapid Detection of Sildenafil Drugs in Liquid Nutraceuticals Based on Surface-Enhanced Raman Spectroscopy Technology

2017-07-03T10:45:26.620536-05:00

In this study, surface-enhanced Raman spectroscopy (SERS) technology was used to rapidly detect illegally added sildenafil drugs. A detailed attribution analysis by density functional theory (DFT) was used to guide specific experiments. The Raman signals were obtained from a silver colloid (Ag col) substrate, and they increased in the presence of the mineral salt, potassium iodide (KI). These methods detected sildenafil in aqueous solutions as low as 1 µg/mL with high signal uniformity (RSD=3.77%). Prior to this study, traditional Raman techniques detected substances in solid samples only. Here, Raman technology detected low contents of sildenaful drugs in liquid nutraceuticals. Therefore, SERS technology has great potential for on-site and real-time detection of illegal drugs in water and in liquid nutraceuticals. A detailed attribution analysis by density functional theory (DFT) was used to guide the surface-enhanced Raman spectroscopy experiments. The SERS signals were obtained from a silver colloid (Ag col) substrate and mineral salts. Here, Raman technology detected low contents of sildenaful drugs in liquid nutraceuticals. Therefore, SERS technology has great potential for on-site and real-time detection of illegal drugs in water and in liquid nutraceuticals.



Functionalization of Carbonyl Compounds via Photoredox Organocatalysis

2017-06-30T09:00:24.457473-05:00

In recent years, a methodology merging photoredox catalysis with organocatalysis termed “photoredox organocatalysis” has emerged to allow the direct, selective and efficient functionalization of the α/β-C of carbonyl compounds under mild reaction condition. In this review, photophysics background of photoredox catalysis is introduced, followed by a report on recent advances in direct α- and β-functionalization of carbonyls with photoredox organocatalysis methodology. With this different reaction modes, valuable synthetic targets including different α/β-functionalized carbonyls are accessible. A methodology merging photoredox catalysis with organocatalysis termed “photoredox organocatalysis” has emerged to allow the direct and selective functionalization of the α/β-C of carbonyl compounds. In this review, photophysics background of photoredox catalysis is introduced, followed by a report on recent advances in direct α- and β-functionalization of carbonyls with photoredox organocatalysis methodology.



Synthesis, Cytotoxic Activity Evaluation of Novel 1,2,3-Triazole Linked Quinazoline Derivatives

2017-06-30T09:00:20.821027-05:00

A series of novel 1,2,3-triazole-quinazoline derivatives were synthesized in five steps starting from anthranilamide by conventional methods. All the title compounds 10a—10r were evaluated for cytotoxic activity against four human cancer cell lines (MGC-803, EC-109, MCF-7 and HGC-27) using MTT assay in vitro. Some of the synthesized compounds exhibited moderate to potent activity against tested cancer cell lines. Among them, compounds 10 h and 10q exhibited excellent growth inhibition against HGC-27 and compound 10 m also possessed excellent activity against MCF-7, with IC50 values less than 1 µmol/L. Especially, compound 10 h was more cytotoxic than 5-fluorouracil against all tested four human cancer cell lines. Compounds 10 h and 10q exhibited excellent growth inhibition against HGC-27 and compound 10 m also possessed excellent activity against MCF-7, with IC50 value less than 1 µmol/L. Especially, compound 10 h is more cytotoxic than 5-fluorouracil with IC50 values of 7.13, 2.17, 4.91 and 0.57 µmol/L against MCF-7, MGC-803, EC-109 and HGC-27, respectively.



Synthesis and Characterization of Aramid Fiber-Reinforced Polyimide/Carbon Black Composites and Their Use in a Supercapacitor

2017-06-30T08:55:18.898166-05:00

The aramid fabric (AF)-reinforced polyimide (PI) composites filled with carbon black (CB) were fabricated by means of a thermal imidization and their mechanical, thermal and electrochemical behaviors were comparatively investigated. Experimental results showed that the tensile strength of composite increased with an increase of the CB, meanwhile, the addition of 5 wt% CB and AF increased the tensile modulus to 5682.0 MPa. The superior mechanical properties of the composites were attributed to the good dispersion and effective stress transfer between the polymer and CB, as evidenced by the results from X-ray diffraction (XRD) and morphological studies. Besides, the thermal-nonoxidative stability of PI was significantly improved by the incorporation of CB and AF. Furthermore, the CB/AF/PI composite was employed as the supercapacitor electrode in the 6 mol/L KOH aqueous electrolyte solution, which exhibited a specific capacitance of 510 F•g−1 at 10 mV•s−1. It also exhibited excellent long-term stability, and the energy density was stable with the increase in the power density. The super performance of the composite electrode is attributed to the synergistic effects of CB particles and organic polymer. Synthesis and Characterization of Aramid Fiber-Reinforced Polyimide/Carbon Black Composites and Their Use in a Supercapacitor



Electrophoretic Deposition of Binder-Free MnO2/Graphene Films for Lithium-Ion Batteries

2017-06-30T08:50:25.76577-05:00

Binder-free, nano-sized needlelike MnO2-submillimeter-sized reduced graphene oxide (nMnO2-srGO) hybrid films with abundant porous structures were fabricated through electrophoretic deposition and subsequent thermal annealing at 500 °C for 2 h. The as-prepared hybrid films exhibit a unique hierarchical morphology, in which nMnO2 with a diameter of 20—50 nm and a length of 300—500 nm is randomly anchored on both sides of srGO. When evaluated as binder-free anodes for lithium-ion half-cell, the nMnO2-srGO composites with a content of 76.9 wt% MnO2 deliver a high capacity of approximately 1652.2 mA•h•g−1 at a current density of 0.1 A•g−1 after 200 cycles. The high capacity remains at 616.8 mA•h•g−1 (ca. 65.1% capacity retention) at a current density as high as 4 A•g−1. The excellent electrochemical performance indicates that the nMnO2-srGO hybrid films could be a promising anode material for lithium ion batteries (LIBs). Binder-free, nano-sized needle-like, MnO2-submillimeter-sized rGO hybrid films with abundant porous structures fabricated through electrophoretic deposition present excellent electrochemical performance of LIBs.



Facile Synthesis of Pd-Ni Nanoparticles on Reduced Graphene Oxide under Microwave Irradiation for Formic Acid Oxidation

2017-06-29T10:55:35.89837-05:00

Pd and PdxNi nanoparticles have been supported on reduced graphene oxide (Pd/rGO and PdxNi/rGO) by using the microwave-assisted heating method in glycol. The morphology, composition and electrochemical performance have been characterized by TEM, XRD, XPS and electrochemical methods. The XRD and XPS results show that there are no PdNi alloy particles formed in PdxNi/rGO and the composites exist mostly in the form of Pd0 and NiOOH species. The electrochemical results reveal that PdxNi/rGO synthesized from the feeding source of Pd and Ni with an atomic ratio of 4∶1 exhibits higher activity, better stability and smaller electron transfer resistance toward formic acid electro-oxidation compared with commercial Pd/C, Pd/rGO and other PdxNi/rGO samples. The excellent electrocatalytic performance indicates that the addition of appropriate amount of Ni can greatly enhance the activity and stability of Pd catalysts for formic acid oxidation. PdxNi particles have been supported on reduced graphene oxide (PdxNi/rGO) by a one-pot reduction method in glycol under microwave irradiation and Pd4Ni/rGO exhibits higher activity, better stability and smaller electron transfer resistance toward formic acid electro-oxidation compared with commercial Pd/C, Pd/rGO and other PdxNi/rGO samples.



Enhancement of Fe3O4/Au Composite Nanoparticles Catalyst in Oxidative Degradation of Methyl Orange Based on Synergistic Effect

2017-06-29T10:55:29.670489-05:00

Enhancement of Fe3O4/Au nanoparticles (Fe3O4/Au NPs) catalyst was observed in the oxidative degradation of methyl orange by employing H2O2 as oxidant. To evaluate the catalytic activity of Fe3O4/Au nanoparticles, different degradation conditions were investigated such as the amounts of catalyst, H2O2 concentration and pH value. Based on our data, methyl orange was degraded completely in a short time. The enhanced catalytic activity and increased oxidation rate constant may be ascribed to synergistic catalyst-activated decomposition of H2O2 to •OH radical, which was one of the strong oxidizing species. Besides, Fe3O4/Au nanoparticles have exhibited satisfying recycle performance for potential industrial application. The synergistic enhancement effect was observed in the oxidative degradation of Methyl Orange (MO) by employing Fe3O4/Au NPs as catalyst and H2O2 as oxidant.



A Facile Synthesis of Benzo[h]quinolines via Silica-TsOH-P2O5 Promoted Condensation of 1-Naphthylamines with 1,3-Diketones under Solvent Free Conditions

2017-06-29T10:50:23.023358-05:00

A facile synthesis of benzo[h]quinolines has been developed via improved Combes reaction. A combination of silica gel, p-toluenesulfonic acid and phosphorus pentoxide was utilized to promote the condensation of 1-naphthylamines with 1,3-diketones under solvent free conditions. In this case, silica gel was used as reaction media, p-toluenesulfonic acid and phosphorus pentoxide were acted as catalyst and dehydrating agent, respectively. A facile and efficient method for the synthesis of benzo[h]quinolines has been developed by using a silica-TsOH-P2O5 combination under solvent free conditions.



Ionothermal Synthesis and Structural Characterization of a Novel Open Framework Zinc Diphosphonate with Carboxylate-like Linker

2017-06-29T10:50:19.669594-05:00

A novel crystalline zinc diphosphonate, (CH3NH3)4Zn2(xbp)2•H2O, denoted as compound 1, was ionothermally synthesized from tetraethyl-p-xylylenebisphosphonate (Texbp) and Zn(OAc)2 in a protic eutectic mixture with urea/methylamine hydrochloride. Its structure was determined by single-crystal X-ray diffraction data and had a special three-dimensional open framework with rhombic channels. Compound 1 belongs to the monoclinic system (space group C2/c), with lattice parameters a=22.6876(19) Å, b=8.7376(7) Å, c=8.1673(9) Å, β=108.146(2)°, V=1538.5(2) Å3, Z=2. Its structure is totally different from the typical organic pillared structure, only two oxygens of the phosphonate group are coordinated with zinc atoms, and the third oxygen exists in the terminal form, which is similar to the popular dicarboxylate linkers in MOFs. The organic cations [CH3NH3]+ of the eutectic mixture played a structure-directing role for constructing this framework and were confined in the pore channels to balance the negative charges resulting from the zinc phosphonate inorganic chains. A novel crystalline zinc diphosphonate with open-framework was ionothermally synthesized from tetraethyl-p-xylylenebisphosphonate and Zn(OAc)2 in a protic eutectic mixture of urea/methylamine hydrochloride. Its structure is completely different from the typical organic pillared structure, resulting from the bidentate mode of phosphate groups similar to dicarboxylate linkers in MOFs.



Asymmetric Synthesis and Antitumor Activity of Spiro-Oxadiazole Derivatives from 1,4:3,6-Dianhydro-D-fructose

2017-06-29T04:30:33.298338-05:00

A series of spiro-oxadiazoles were synthesized from 1,4:3,6-dianhydro-D-fructose and hydrazides via a stereo- selective two-step reaction sequence. The structures of newly synthesized compounds were established by spectral analysis. The absolute configuration of compound 2a was further confirmed by single crystal X-ray analysis. All the synthesized compounds were screened for their in vitro antitumor activity, showing that these compounds have poor inhibitory activities against A549, MGC-803 tumor cells. A series of spiro-oxadiazoles were synthesized from 1,4:3,6-dianhydro-D-fructose and hydrazides via a stereo-selective two-step reaction sequence. The structures of the newly synthesized compounds were established by spectral analysis. The absolute configuration of compound 2a was further confirmed by single crystal X-ray analysis. All the synthesized compounds were screened for their in vitro antitumor activity, showing that these compounds have poor inhibitory activity against A549, MGC-803 tumor cells.



Copper-Catalyzed Direct Oxyphosphorylation of Enamides with P(O)-H Compounds and Dioxygen

2017-06-29T04:30:22.09427-05:00

A simple and convenient copper-catalyzed direct oxyphosphorylation of enamides with P(O)-H compounds and dioxygen has been developed under mild conditions. This methodology can allow the synthesis of a series of valuable β-ketophosphine oxides/β-ketophosphonates in moderate to good yields with a broad substrate scope simply by using readily-available starting materials. A simple and convenient copper-catalyzed direct oxyphosphorylation of enamides with P(O)-H compounds and dioxygen leading to β-ketophosphine oxides/β-ketophospho- nates has been developed.



Phthalimide and Naphthalimide end-Capped Diketopyrrolopyrrole for Organic Photovoltaic Applications

2017-06-29T04:25:47.354552-05:00

Two small molecules named PI-DPP and NI-DPP with a DPP core as the central strong acceptor unit and phthalimide/naphthalimide as the terminal weak acceptor were designed and synthesized. The effects of terminal phthalimide/naphthalimide units on the thermal behavior, optical and electrochemical properties, as well as the photovoltaic performance of these two materials were systematically studied. Cyclic voltammetry revealed that the lowest unoccupied molecular orbitals (LUMO) (~ -3.6 eV) of both molecules were intermediate to common electron donor (P3HT) and acceptor (PCBM). This indicated that PI-DPP and NI-DPP may uniquely serve as electron donor when blended with PCBM, and as electron acceptor when blended with P3HT, where sufficient driving forces between DPPs and PCBM, as well as between P3HT and DPPs should be created for exciton dissociation. Using as electron donor materials, PI-DPP and NI-DPP devices exhibited low power conversion efficiencies (PCEs) of 0.90% and 0.76% by blending with PCBM, respectively. And a preliminary evaluation of the potential of the NI-DPP as electron acceptor material was carried out using P3HT as a donor material, and P3HT:NI-DPP device showed a PCE of 0.6%, with an open circuit voltage (VOC) of 0.7 V, a short circuit current density (JSC) of 1.91 mA•cm-2, and a fill factor (FF) of 45%. NI-DPP can serve as both an electron donor and acceptor in blends with PC71BM or P3HT, respectively.



Synthesis and Characterization of Lu3N@C80O

2017-06-15T10:55:19.748268-05:00

Oxygenated hollow cage fullerenes have been intensively studied due to their applications in biomedicine in recent years. Clusterfullerenes have become a focus of endohedral fullerene researches for their exceptionally high yield and thermal stabilities. However, oxide derivatives of clusterfullerene remain unexplored to date. Herein, we present the photochemical synthesis of an oxide derivative of clusterfullerene, Lu3N@C80O, for the first time. The compound was characterized by matrix-assisted laser desorption ionization time-of-flight mass spectrometry, UV–vis-NIR, cyclic voltammetry, and FTIR spectroscopy. The results suggest that one oxygen atom bridges with the fullerene cage after the oxidation of Lu3N@C80. Moreover, the oxidation has a major impact on the electrochemical behavior of Lu3N@C80. We present the photochemical synthesis of an oxide derivative of clusterfullerene, Lu3N@C80O for the first time. The compound was characterized by matrix-assisted laser desorption ionization time-of-flight mass spectrometry, UV–vis-NIR, cyclic voltammetry, and FTIR spectroscopy. The results suggest that one oxygen atom bridges with the fullerene cage after the oxidation of Lu3N@C80.



A Novel Method for Preparation of 2-Chloro Enesulfonamides

2017-06-15T10:50:22.181138-05:00

A novel method for the synthesis of 2-chloro enesulfonamides via the one-pot addition-elimination of N-chloro-N-fluorobenzenesulfonamides (CFBSA) to styrenes in the presence of Et3N is described. A total of 20 examples are presented to illustrate this concept including various of styrenes. A novel metal-free method for the synthesis of 2-chloro enesulfonamides from styrenes is described. The addition of CFBSA to styrenes and the elimination of HF in the presence of Et3N were complished in a one-pot process under mild conditions in moderate yields.



Photodynamic Therapy of Oligoethylene Glycol-Dendronized Reduction-Sensitive Porphyrins

2017-06-12T11:01:31.326475-05:00

Graphene oxide (GO) and its functionalized derivatives have attracted increasing attention in medical treatment. Herein, a reduction sensitive PEI-GO-SS-TPP was synthesized for photodynamic therapy. More than 80% porphyrin release was observed in the presence of 10 mmol•L−1 DTT in one day. The confocal laser scanning microscopy confirmed that the cell uptake efficiency of PEI-GO-SS-TPP was remarkably enhanced as compared to free porphyrin which was significantly dependent on incubation time. For photodynamic therapy, GSH-OEt could effectively increase the photodynamic therapy efficiency of PEI-GO-SS-TPP. Compared with free porphyrin, the toxicity from PEI-GO-SS-TPP is much higher with a low IC50 (2.1 µg/mL) value. All results indicate that the PEI-GO-SS-TPP PSs are promising for photodynamic therapy. A reduction sensitive functionalized graphene oxide PEI-GO-SS-TPP was synthesized. The carrier PEI-GO could effectively enhance the uptake efficiency of porphyrin. Compared with free porphyrin, the toxicity from PEI-GO-SS-TPP is much higher with a low IC50 value, indicating that the PEI-GO-SS-TPP PSs are promising for photodynamic therapy.



Molecular Diversity of Three-Component Reaction of β-Enamino Imide, Malononitrile and Cyclic α-Diketones

2017-06-12T10:45:21.186163-05:00

The base promoted three-component reaction of β-enamino imide, malononitrile and various cyclic α-diketones in acetonitrile showed interesting molecular diversity. The reactions with acenaphthylene-1,2-dione and ninhydrin afforded functionalized spiro[indene-2,4'-pyrrolo[3,4-b]pyridines] and spiro[acenaphthylene-1,4'-pyrrolo[3,4-b]pyridines] in good yields. The similar reaction of phenanthrene-9,10-dione resulted in the formation of the unexpected complex phenanthro[9',10':4,5]furo[2,3-c]pyrrolo[3,4-b]pyrroles in satisfactory yields. The three-component reaction of β-enamino imide and malononitrile with acenaphthylene-1,2-dione or ninhydrin afforded functionalized spiro[indene-2,4'-pyrrolo[3,4- b]pyridines] and spiro[acenaphthylene-1,4'-pyrrolo[3,4-b]pyridines]. The similar reaction of phenanthrene-9,10-dione resulted in phenanthro[9',10':4,5]furo[2,3-c]pyrrolo- [3,4-b]pyrroles.



Chemoselective Synthesis of Novel Heterocyclic [3.3.3]Propellane Derivatives via a One-pot Three-component Reaction

2017-06-12T10:45:19.253222-05:00

A highly chemoselective method for the synthesis of heterocyclic [3.3.3]propellane derivatives was developed via sequential three-component reactions of acenaphthenequinone, malononitrile/cyanoacetate and a variety of 1,3-dicarbonyl compounds under mild conditions in ethanol. A plausible mechanism for this type of reaction was proposed. The value of this method was highlighted by its high selectivity, simple procedures, and good yields.



Facile Synthesis of Spirooxindole-Cyclohexenes via Phosphine-Catalyzed [4 + 2] Annulation of α-Substituted Allenoates

2017-06-12T10:40:22.514886-05:00

A phosphine-catalyzed [4 + 2] annulation of α-substituted allenoate with exocyclic alkene moiety of oxindoles or indan-1,3-diones has been developed. Thus, under the catalysis of PPh3 (20 mol%), a series of spirooxindole- or spiroindan-1,3-dione-cyclohexenes have been obtained in moderate to excellent yields and regioselectivity from the annulations of α-methyl allenoates with 3-methyleneoxindoles or 2-methyleneindan-1,3-diones. This method offers an easy access to structurally novel spirocyclohexenes.



Asymmetric Synthesis of Chiral α-Substituted Mercaptoglycine Derivatives via α-Sulfenylation of Ni(II) Complex of Glycine and S-Substituted 4-Methylbenzenesulfonothioate

2017-06-12T10:40:20.114446-05:00

The asymmetric α-sulfenylation of Ni(II) complex of glycine with S-substituted 4-methylbenzenesulfonothioate is reported. Due to the mild and simple reaction conditions, this asymmetric reaction is compatible with various functional groups.



Cover Picture: A Novel Dual Channel Fluorescent Probe for Ca2+ and Zn2+ Based on a Coumarin Schiff Base (Chin. J. Chem. 8/2017)

2017-08-17T08:52:31.036002-05:00

The cover picture shows a novel dual channel fluorescent probe for Ca2+ and Zn2+ based on a coumarin Schiff base. The probe displays a solvent dependent dual sensing, viz., recognition of Ca2+ in DMF-H2O (9∶1, V/V) solution based on C = N isomerization, photoinduced electron transfer (PET) inhibition and chelation-enhanced fluorescence (CHEF) mechanism as well as detection of Zn2+ in H2O-CH3OH (9∶1, V/V) solution by excited-state intramolecular proton transfer (ESIPT) and CHEF processes. More details are discussed in the article by Guo et al. on page 1263–1269. The cover picture shows a novel dual channel fluorescent probe for Ca2+ and Zn2+ based on a coumarin Schiff base. The probe displays a solvent dependent dual sensing, viz., recognition of Ca2+ in DMF-H2O (9∶1, V/V) solution based on C = N isomerization, photoinduced electron transfer (PET) inhibition and chelation-enhanced fluorescence (CHEF) mechanism as well as detection of Zn2+ in H2O-CH3OH (9∶1, V/V) solution by excited-state intramolecular proton transfer (ESIPT) and CHEF processes. More details are discussed in the article by Guo et al. on page 1263–1269.



Inside Cover: Study of Karstedt's Catalyst for Hydrosilylation of a Wide Variety of Functionalized Alkenes with Triethoxysilane and Trimethoxysilane (Chin. J. Chem. 8/2017)

2017-08-17T08:52:33.733539-05:00

The inside cover picture shows the excellent catalytic performance of Karstedt's catalyst for the hydrosilylation of olefins terminated with various functional groups (amino, alkoxyl, carboxylic, hydroxyl, aldehyde, etc.) with the trimethoxysilane and triethoxysilane reagents in terms of the yield and selectivity. More details are discussed in the article by Gao et al. on page 1227–1230. The inside cover picture shows the excellent catalytic performance of Karstedt's catalyst for the hydrosilylation of olefins terminated with various functional groups (amino, alkoxyl, carboxylic, hydroxyl, aldehyde, etc.) with the trimethoxysilane and triethoxysilane reagents in terms of the yield and selectivity. More details are discussed in the article by Gao et al. on page 1227–1230.



Contents: Chin. J. Chem. 8/2017

2017-08-17T08:52:30.712718-05:00




Asymmetric Cationic [P, O] Type Palladium Complexes in Olefin Homopolymerization and Copolymerization

2017-05-12T10:00:29.742845-05:00

Metal-catalyzed ethylene homopolymerization and ethylene-polar monomer copolymerization to produce new kinds of polyolefins with novel microstructures are of great interest. So far, there are some disadvantages for traditional transition metal catalyst systems. Therefore, it is critical to develop new catalysts or alternative strategies. In recent years, some cationic [P, O] palladium complexes have been demonstrated with the abilities to obtain oligomers and the high molecular weight polymers. Most importantly, these complexes showed high activity and generated polymers with specific microstructures when used for copolymerization of ethylene with industrially relevant polar monomers. This review summarizes several types of high performance cationic [P, O] palladium catalysts in ethylene oligomerization, ethylene homopolymerization and the copolymerization of ethylene with polar monomers. Specially, the regulation of steric and electronic effects at specific sites of the metal complexes was focused. This review summarizes several types of high performance cationic [P, O] palladium catalysts in ethylene oligomerization, ethylene homopolymerization and the copolymerization of ethylene with polar monomers.



Synthesis of 1,2,4-Triazine Compounds via Two Distinct One-Pot Domino Protocols

2017-06-15T10:55:23.623184-05:00

1,2,4-Triazine compounds were synthesized via two coupled domino strategies employing simple and readily available arylacetaldehydes/arylethyl alcohols as starting materials. The reactions proceed smoothly in one pot with the advantages of high functional groups tolerance, being transition metal-free, and employing environmentally friendly oxidants such as I2 and IBX, providing access to the desired 1,2,4-triazine products in excellent yields. 1,2,4-Triazine compounds were synthesized via two coupled domino strategies employing simple and readily available arylacetaldehydes/arylethyl alcohols as starting materials. The reactions proceed smoothly in one pot with the advantages of high functional groups tolerance, being transition metal-free, and employing environmentally friendly oxidants such as I2 and IBX, providing access to the desired 1,2,4-triazine products in excellent yields.



Study of Karstedt's Catalyst for Hydrosilylation of a Wide Variety of Functionalized Alkenes with Triethoxysilane and Trimethoxysilane

2017-06-02T04:29:04.662048-05:00

The hydrosilylation is one of the most important methods for the synthesis of organosilicon compounds. Karstedt's catalyst [Ptn(H2C=CHSiMe2OSiMe2CH=CH2)m] is a kind of platinum catalyst which is widely used in the hydrosilylation. In this paper, we studied the catalytic activity of Karstedt's catalyst for the hydrogenation of olefins and especially aminated alkenes with trimethoxysilane and triethoxysilane, and demonstrated the excellent performance in terms of the yield and selectivity. Karstedt's catalyst [Ptn(H2C = CHSiMe2OSiMe2CH = CH2)m] demonstrated the excellent performance for the hydrogenation of olefins and especially aminated alkenes with trimethoxysilane and triethoxysilane in terms of the yield and selectivity.



Functional Ionic Liquids Promoted Double Michael Reaction of Benzofuran-3-one or 1-Indone and Symmetric Dienones: Construction of Spiro[benzofuran-2,1’-cyclohexane]-3-one or Spiro[cyclohexane-1,2’-indene]-1’,4(3’H)-dione Derivatives

2017-05-29T05:20:36.450726-05:00

The double Michael reactions between benzofuran-3-one or 1-indone and symmetric dienones in the presence of catalytic ionic liquids were successfully developed and spiro[benzofuran-2,1’-cyclohexane]-3-one or spiro[cyclohexane-1,2’-indene]-1’,4(3’H)-dione derivatives containing a spiro quaternary stereogenic center, which widely exist in biologically active products and building blocks in organic synthesis, were obtained in excellent yields (up to 99%). This catalytic system was also extended to the double Michael reaction of less reactive 1-indone and the desired products were also obtained in 31%-62% yields. The catalytic system was highly active and efficient for a broad of substrates under mild conditions. The double Michael reactions between benzofuran-3-one or 1-indone and symmetric dienones in the presence of catalytic ionic liquids were successfully developed and the desired products were obtained in excellent yields (up to 99%). This catalytic system was also extended to the double Michael reaction of less reactive 1-indone and the desired products were obtained in 31%-62% yields.



Copper(II) Acetylacetonate: An Efficient Catalyst for Huisgen-Click Reaction for Synthesis of 1,2,3-Triazoles in Water

2017-06-02T04:25:37.884294-05:00

An efficient and green copper(II) acetylacetonate-catalyzed protocol for the Huisgen-click reaction in water at 100 °C has been established. The protocol was not only suitable for the reaction between organic azides and alkynes, but also suitable for one-pot three-component reaction among alkyl halides, NaN3 and alkynes. An efficient and green copper(II) acetylacetonate-catalyzed protocol for the Huisgen- click reaction in water at 100 °C has been established. The protocol was not only suitable for the reaction between organic azides and alkynes, but also suitable for one-pot three-component reaction among alkyl halides, NaN3 and alkynes



A Novel Sarsolenane Diterpene as a PTP1B Inhibitor from Hainan Soft Coral Sarcophyton trocheliophorum Marenzeller

2017-06-07T09:35:19.996622-05:00

A novel sarsolenane diterpene, named secodihydrosarsolenone (1), as a minor component was obtained from the South China Sea soft coral Sarcophyton trocheliophorum Marenzeller. Its structure was elucidated by detailed spectroscopic analysis. Compound 1 exhibited moderate inhibitory activity (IC50=13.7 µmol•L−1) against protein tyrosine phosphatase 1B (PTP1B), a key target for the treatment of type 2 diabetes, representing the first report of PTP1B inhibitory activity for sarsolenane diterpenes. This discovery promotes computational prediction of binding mode between the enzyme and the metabolite, suggesting a crucial role of the residues Tyr46, Ser216 and Arg221 in the binding action. A novel sarsolenane diterpene 1 as a minor component from the South China Sea soft coral S. trocheliophorum, exhibited moderate inhibitory activity (IC50 = 13.7 µmol•L−1) against PTP1B. This discovery promotes computational prediction of binding mode between the enzyme and the metabolite, suggesting a crucial role of the residues Tyr46, Ser216 and Arg221 in the binding action.



Regio- and (E)-Stereoselective Triborylation of Propargylic Carbonates

2017-07-25T06:35:41.680641-05:00

An efficient synthesis of (E)-alken-1,2,3-triboronates form readily available propargylic carbonates is described. The reaction enjoys excellent regio- and E-selectivity and many synthetically useful functional groups can be tolerated. Based on mechanistic studies, a two-step mechanism via 1,2-allenyl boronate intermediate is proposed. The triborylation of readily available propargylic carbonates under co-catalysis of Pd and Cu forming (E)-alken-1,2,3-triboronates has been developed. The reaction enjoys an excellent regio- and E-selectivity tolerating a broad scope with many synthetically useful functional groups.



A Novel Dual Channel Fluorescent Probe for Ca2+ and Zn2+ Based on a Coumarin Schiff Base

2017-06-13T08:30:29.789235-05:00

A novel coumarin Schiff base fluorescent probe ethyl 7-hydroxycoumarin-3-carboxylate-8-formaldehyde benzoyl hydrazone (EBH) has been designed and synthesized which shows solvent dependent dual sensing, viz., recognition of Ca2+ in DMF-H2O (9∶1, V/V) solution based on C = N isomerization, photoinduced electron transfer (PET) inhibition and chelation-enhanced fluorescence (CHEF) mechanism as well as detection of Zn2+ in H2O-CH3OH (9∶1, V/V) solution by excited-state intramolecular proton transfer (ESIPT) and CHEF processes. The structure of the probe EBH has been confirmed by single-crystal X-ray diffraction analysis. Meanwhile, the probe was also used to image intracellular Zn2+ ions in MCF-7 cells with a good performance. Novel coumarin Schiff base fluorescent probe has been designed and synthesized which shows a solvent dependent dual sensing, viz., recognition of Ca2+ in DMF-H2O (9∶1, V/V) solution based on C = N isomerization, photoinduced electron transfer (PET) inhibition and chelation-enhanced fluorescence (CHEF) mechanism as well as detection of Zn2+ in H2O-CH3OH (9∶1, V/V) solution by excited-state intramolecular proton transfer (ESIPT) and CHEF processes.



Allosteric Modulation of Human Serum Albumin Induced by Peptide Ligand

2017-06-09T04:40:24.216739-05:00

Human serum albumin (HSA) is an abundant protein in plasma that can bind and transport many small molecules, and the corresponding affinity-controlled drug delivery shows great advantage in the biological system. Peptide SA06 is a reported ligand comprising 20 amino acids, and is known to non-covalently bind with HSA to extend the lifetime and improve the pharmacokinetic performance. The structural information of the HSA-peptide complex is keen for obtaining molecular insight of the binding mechanism. We studied the secondary structural change and structure-affinity relations of Peptide SA06 with HSA by using circular dichroism (CD) spectroscopy in solution. Noticeable allosteric effect can be identified by compositional increase of α-helix structures when the peptide was co-incubated with HSA. Furthermore, the equilibrium dissociation constant of Peptide SA06 with HSA can be determined by CD-based method. This work provides structural evidence on the allosteric interaction between peptide ligand and HSA, and sheds light on optimization of therapeutic properties in the affinity-controlled delivery systems. This work studied allosteric modulation of human serum albumin induced by peptide ligand, figured out the binding affinity, and provided structural evidence on the interaction mechanism of albumin-peptide complex.



Direct Observation of Growth and Self-assembly of Pt Nanoclusters in Water with the Aid of a Triblock Polymer Using in situ Liquid Cell Transmission Electron Microscopy (TEM)

2017-06-12T11:01:32.455909-05:00

Triblock copolymers are playing important roles in nanomaterial synthesis, and the nanomaterial forming mechanisms need to be studied in detail. In situ liquid cell transmission electron microscopy (TEM) is a powerful tool for real time observation of the dynamic growth behavior of nanomaterials in liquid with high resolution, and could be used for the above task. Here we report the observation of the growth and self-assembly of Pt nanoclusters with the aid of an ethylene oxide-propylene oxide-ethylene oxide triblock copolymer (PEO-PPO-PEO) F127 using in situ liquid cell TEM, with the nanocluster growth and formation procedures being tracked. Nano objects were seen to appear, drift and rotate with time, and then form into certain shaped nanoclusters under the electron beam irradiation. Further interestingly, in the thicker liquid layer region, the nanoclusters appeared to be fluffy, with average size keeping increase with time, while in the thinner region, the clusters were thinner, and got densified with time. The difference in precursor availability due to liquid layer thickness and charging effects is attributed to such a phenomenon. The growth and self-assembly of Pt nanoclusters with the aid of F127 surfactants are directly observed using in situ liquid cell TEM, and a surfactant guided nanocluster formation mechanism is proposed. Dramatic differences are found on the cluster forming behaviour and final morphologies between thick and thin liquid regions. The difference in precursor availability and charging effects are attributed to the different growth behaviour in different thickness regions.



Total Synthesis of (+)-Chinensiolide B from α-Santonin

2017-05-31T05:35:25.738086-05:00

A short and efficient total synthesis of (+)-chinensiolide B is reported, starting from commercially available α-santonin. This strategy could be used for rapid preparation of chinensiolides and their derivative for further structure activity relationship studies. A short and efficient total synthesis of (+)-chinensiolide B is reported from α-santonin in 10 steps with 18.6% overall yield.



A New Microporous Metal-Organic Framework for Highly Selective C2H2/CH4 and C2H2/CO2 Separation at Room Temperature

2017-06-12T10:50:18.968966-05:00

We have successfully designed and synthesized a new tetracarboxylic linker, which constructed its first three-dimensional microporous metal-organic framework (MOF), [Cu2(DDPD)(H2O)2]•Gx (ZJU-13, H4DDPD=5,5'-(2,6-dihydroxynaphthalene-1,5-diyl)diisophthalic acid, ZJU=Zhejiang University, G = guest molecules) via solvothermal reaction. Due to open Cu2+ sites and optimized pore size, the activated ZJU-13a displays high separation selectivity for C2H2/CH4 of 74 and C2H2/CO2 of 12.5 at low pressure by using Ideal Adsorbed Solution Theory (IAST) simulation at room temperature. A microporous three-dimensional metal organic framework with open metal sites and optimized pore sizes was synthesized to realize highly selective C2H2/CH4 and C2H2/CO2 gas separation.



Amorphous MnO2 as Cathode Material for Sodium-ion Batteries

2017-06-15T10:50:26.763179-05:00

Amorphous MnO2 has been prepared from the reduction of KMnO4 in ethanol media by a facile one-step wet chemical route at room temperature. The electrochemical properties of amorphous MnO2 as cathode material in sodium-ion batteries (SIBs) are studied by galvanostatic charge/discharge testing. And the structure and morphologies of amorphous MnO2 are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectra. The results reveal that as-synthesized amorphous MnO2 electrode material exhibits a spherical morphology with a diameter between 20 and 60 nm. The first specific discharge capacity of the amorphous MnO2 electrode is 123.2 mAh•g−1 and remains 136.8 mAh•g−1 after 100 cycles at the current rate of 0.1 C. The specific discharge capacity of amorphous MnO2 is maintained at 139.2, 120.4, 89, 68 and 47 mAh•g−1 at the current rate of 0.1 C, 0.2 C, 0.5 C, 1 C and 2 C, respectively. The results indicate that amorphous MnO2 has great potential as a promising cathode material for SIBs. Amorphous MnO2 has been prepared from the reduction of KMnO4 in ethanol media by a facile one-pot wet chemical route at room temperature. When employed as cathode material in SIBs, the amorphous MnO2 electrode exhibits high reversible specific capacity, stable cycling performance and good rate capability. The reversible discharge capacity of the amorphous MnO2 electrode is maintained at 136.8 mAh•g−1 after 100 cycles at 0.1 C. And the electrode delivers reversible discharge capacities of 120.4, 89, 68 and 47 mAh•g−1 at 0.2 C, 0.5 C, 1 C and 2 C, respectively.



Ionic Liquid Mediated Synthesis of Lath Shaped CuO Micro-Assembles as Extremely Stable Anode Material for Lithium-Ion Batteries

2017-05-29T05:31:45.520469-05:00

A novel lath-shaped CuO microassemble consisting of well-crystalized ultrafine nanocrystals was prepared by an ionothermal method with the assistance of ionic liquids (ILs, 1-butyl-3-methylimidazolium tetrafluoroborate). As anode material of lithium ion batteries, the ILs-CuO exhibits high specific capacity, durability and good rate performance, superior to bare CuO. At a high current density of 1000 mA•g−1, after 100 cycles, ILs-CuO still retains a discharge capacity of 483.2 mAh•g−1. The improved electrochemical performances could be ascribed to the unique microscale lath-shape CuO assembles composed of ultrafine nanostructure. A novel lath-shaped CuO microassemble consisting of well-crystalized ultrafine nanocrystals was prepared by an ionothermal method with the assistance of ionic liquids (ILs, 1-butyl-3-methylimidazolium tetrafluoroborate). As anode material of lithium ion batteries, the ILs-CuO exhibits high specific capacity, durability and good rate performance, superior to bare CuO. At a high current density of 1000 mA•g−1, after 100 cycles, ILs-CuO still retains a discharge capacity of 483.2 mAh•g−1. The improved electrochemical performances could be ascribed to the unique microscale lath-shape CuO assembles composed of ultrafine nanostructure.



Amperometric Biosensor for Detection of Phenolic Compounds Based on Tyrosinase, N-Acetyl-L-cysteine-capped Gold Nanoparticles and Chitosan Nanocomposite

2017-05-31T05:35:21.467367-05:00

A novel biosensor was fabricated based on the immobilization of tyrosinase and N-acetyl-L-cysteine-capped gold nanoparticles onto the surface of the glassy carbon electrode via the film forming by chitosan. The NAC-AuNPs (N-acetyl-L-cysteine-capped gold nanoparticles) with the average size of 3.4 nm had much higher specific surface area and good biocompatibility, which were favorable for increasing the immobilization amount of enzyme, retaining the catalytic activity of enzyme and facilitating the fast electron transfer. The prepared biosensor exhibited suitable amperometric responses at −0.2 V for phenolic compounds vs. saturated calomel electrode. The parameters of influencing on the working electrode such as pH, temperature, working potential were investigated. Under optimum conditions, the biosensor was applied to detect catechol with a linear range of 1.0 × 10−7 to 6.0 × 10−5 mol•L−1 , and the detection limit of 5.0 × 10−8 mol•L−1 (S/N=3). The stability and selectivity of the proposed biosensor were also evaluated. A novel biosensor was fabricated based on the immobilization of tyrosinase and N-acetyl-L-cysteine-capped gold nanoparticles onto the surface of the glassy carbon electrode via the film forming by chitosan. The NAC-AuNPs with the average size of 3.4 nm had much higher specific surface and good biocompatibility, which were favorable for increasing the immobilization amount of enzyme, retaining the catalytic activity of enzyme and facilitating the fast electron transfer.



Sensitive and Selective Fluorescent and Colorimetric Sensor for Ag+ Based on the Supramolecular Self-Assembly in Semi-Water

2017-05-25T09:55:24.323588-05:00

Specific recognition of ultratrace levels of ions in semi-water using super-quicker methods is still a challenge for environmental monitoring. Herein we report a fluorescent and colormetric sensor (ZH) based on supramolecular self-assembly, whose structure was destroyed by the addition of ultratrace of silver ions. The process promoted either naked eye visible color changes or fluorescence intensity quenched in conjunction with a wide pH range. Systematic studies revealed very high selectivity (0.07 µmol/L) for silver ions, and other common cations, e.g., Hg2+, Cu2+, Cd2+, Pb2+ had nearly no influence on the sensing behavior. This sensor also served as a multiple use of component in sensing materials by addition of I− into the mixture of ZH and Ag+ (about 5 times). What's more, ZH containing filter paper emerged distinct color and fluorescence changes upon exposure to silver (Ag+), which could be used as a portable method to undertake field testing for Ag+. In this paper, a fluorescent and colorimetric sensor based on the supramolecular self-assembly was designed and synthesized, which could detect Ag+ in aqueous solution with high sensitivity and selectivity. It had a remarkable ON–OFF type fluorescent signaling behavior and obvious color change from yellow to buff by adding Ag+ into the solution of ZH.



A MnOOH-Polyaniline Nanocomposite Modified Gold Electrode for Electrochemical Sensing of Nitrite

2017-06-02T04:29:22.864156-05:00

A novel non-enzymatic nitrite sensor was fabricated by immobilizing MnOOH-PANI nanocomposites on a gold electrode (Au electrode). The morphology and composition of the nanocomposites were investigated by transmission electron microscopy (TEM) and Fourier transform infrared spectrum (FTIR). The electrochemical results showed that the sensor possessed excellent electrocatalytic ability for NO2− oxidation. The sensor displayed a linear range from 3.0 μmol•L−1 to 76.0 mmol•L−1 with a detection limit of 0.9 μmol•L−1 (S/N = 3), a sensitivity of 132.2 μA•L•mol−1•cm−2 and a response time of 3 s. Furthermore, the sensor showed good reproducibility and long-term stability. It is expected that the MnOOH-PANI nanocomposites could be applied for more active sensors and used in practice for nitrite sensing. A novel non-enzymatic nitrite sensor based on MnOOH-PANI nanocomposites was fabricated and used for electrochemical sensing of nitrite.



Design, Synthesis and Biological Evaluation of Pentacyclic Triterpene Dimers as HCV Entry Inhibitors

2017-07-10T05:30:22.038236-05:00

A series of triterpene dimers bearing different scaffold were designed and synthesized via CuAAC reaction. Their anti-HCV entry activities were evaluated by HCVpp and VSVpp entry assays. It was found that echinocystic acid (EA) and its dimer were still necessary for maintaining anti-HCV entry activity, and replacement of EA by other triterpenes might significantly decrease its anti-viral activities. Using a linker bearing a piperazine group, compound 14 dramatically increased its potency with IC50 at 2.87 nmol/L. In addition, the undesired hemolytic effect of all these compounds was removed. A series of triterpene dimers bearing different scaffold were designed and synthesized via CuAAC reaction. Their anti-HCV entry activities were evaluated by HCVpp and VSVpp entry assays. Using a linker bearing a piperazine group, compound 14 dramatically increased its potency with IC50 at 2.87 nmol/L.



Hydrogen Storage on Li Coated BC3 Honeycomb Sheet

2017-06-07T09:30:29.20333-05:00

Using density functional theory, we investigated the hydrogen storage capacity of Li coated BC3 honeycomb sheet. Our result indicates 18 H2 molecules can be adsorbed on BC3Li6 complex with a storage gravimetric density of 9.68 wt% and the average adsorption energy reaches 0.206 eV/H2. This is desirable for absorbing and desorbing H2 molecules at near ambient conditions. Using density functional theory, we investigated the hydrogen storage capacity of Li coated BC3 honeycomb sheet. Our result indicates that when six Li atoms coated, the binding energy of each Li atom is 3.20 eV/atom, larger than the cohesive energy 1.63 eV/atom of bulk Li and prevents Li atoms from aggregation. Meanwhile, The largest hydrogen gravimetric density is 9.68 wt% and this is higher than the year 2020 target by the US Department of Energy. Also, the adsorption energy per H2 is 0.206 eV, which is desirable for absorbing and desorbing H2 molecules at nearly ambient conditions



Inside Back Cover: Allosteric Modulation of Human Serum Albumin Induced by Peptide Ligand (Chin. J. Chem. 8/2017)

2017-08-17T08:52:30.613627-05:00

The inside back cover picture shows the allosteric modulation of human serum albumin (HSA) induced by the Peptide SA06 ligand. Peptide SA06 is a reported peptide ligand comprising 20 amino acids, and is known to non-covalently bind with HSA to extend the lifetime and improve the pharmacokinetic performance of drug molecules. The structural evidence on the allosteric interaction between peptide ligand and HSA, and the structure-affinity relations of the binding mechanism have been revealed in this work, which can also shed light on optimization of therapeutic properties in the affinity-controlled delivery systems. More details are discussed in the article by Wang et al. on page 1270–1277. The inside back cover picture shows the allosteric modulation of human serum albumin (HSA) induced by the Peptide SA06 ligand. Peptide SA06 is a reported peptide ligand comprising 20 amino acids, and is known to non-covalently bind with HSA to extend the lifetime and improve the pharmacokinetic performance of drug molecules. The structural evidence on the allosteric interaction between peptide ligand and HSA, and the structure-affinity relations of the binding mechanism have been revealed in this work, which can also shed light on optimization of therapeutic properties in the affinity-controlled delivery systems. More details are discussed in the article by Wang et al. on page 1270–1277.



Back Cover: Direct Observation of Growth and Self-assembly of Pt Nanoclusters in Water with the Aid of a Triblock Polymer Using in situ Liquid Cell Transmission Electron Microscopy (TEM) (Chin. J. Chem. 8/2017)

2017-08-17T08:52:30.972156-05:00

The back cover picture shows schematic of direct in situ liquid cell TEM observation of electron bean induced growth and self-assembly of nanoclusters in water with the aid of a triblock copolymer. The growth and self-assembly of the Pt nanoclusters with the aid of triblock copolymer F127 are directly observed, and a surfactant guided nanocluster formation mechanism is proposed. Dramatic differences are found on the cluster forming behavior and final morphologies between thick and thin liquid regions. The difference in precursor availability and charging effects are attributed to the different growth behavior in different thickness regions. More details are discussed in the article by Chen et al. on page 1278–1283. The back cover picture shows schematic of direct in situ liquid cell TEM observation of electron bean induced growth and self-assembly of nanoclusters in water with the aid of a triblock copolymer. The growth and self-assembly of the Pt nanoclusters with the aid of triblock copolymer F127 are directly observed, and a surfactant guided nanocluster formation mechanism is proposed. Dramatic differences are found on the cluster forming behavior and final morphologies between thick and thin liquid regions. The difference in precursor availability and charging effects are attributed to the different growth behavior in different thickness regions. More details are discussed in the article by Chen et al. on page 1278–1283.