Solvothermal synthesis of nanoscaled LiFePO4 with thinner thickness along [010] direction

Single-phased nanosized LiFePO₄ with thinner thickness along [010] crystallographic direction were successfully fabricated under solvothermal condition by using glycerol as co-solvent. The as-obtained product with thinner thickness is beneficial for fast migration of Li ions in the olivine-structured LiFePO₄, hence exhibiting excellent electrochemical performance.     

Microwave-Assisted Mannich Reaction of 2-Hydroxy-chalcones

A series of Mannich base derivatives of 2-hydroxy-chalcones were obtained expediently in good to excellent yields by microwave-assisted Mannich reaction. The regioselectivity of the reaction occurred preferentially at the C-3 position of the 2-hydroxy-chalcone backbone. In comparison with conventional results, results from microwave possesses give better yields in shorter times. Further vasorelaxation assay showed that 2-hydroxy-3-((4-methylpiperazin-1-yl)methyl)-4,6-dimethoxymethoxy-3′-bromo-chalcone 8 significantly decreased maximal PE-induced contraction (Emax = 100 ± 5.97%, EC₅₀ = 10.2 ± 0.51 µM).     

Assembly of peptide–thiophene conjugates: the influence of peptide content and location

Biomolecule-directed self-assembly of π-conjugated oligomers has attracted great attention in the past decade. In this contribution, two conjugates composed of quaterthiophene and tetrapeptide (Gly-Val-Gly-Val) were synthesised, namely peptide–thiophene–peptide (PTP) and thiophene–peptide–thiophene (TPT), to investigate the influence of peptide content ratio and its location in the molecular structures on the nanostructures and properties of the assemblies. Both conjugates formed organogels consisting of left-handed twisted nanostructures; however, anti-parallel β-sheets were observed in PTP while parallel β-sheets were obtained for TPT, although in both cases oligothiophenes adopted an H-like stacking mode. Obvious solvent-induced supramolecular chirality inversion from the oligothiophene segment was observed for PTP while such phenomenon was not clear for TPT. PTP and TPT gels also showed different stabilities towards temperature increase, as evidenced by variable-temperature circular dichroism study. From the data, it is suggested that the rational design of the location and ratio of peptide plays a key role in constructing materials with determined properties based on peptide–thiophene conjugates.     

Fabrication of sulfonated mesoporous carbon by evaporation induced self-assembly/carbonization approach and its supercapacitive properties

Synthesis of functionalized mesoporous carbon by an easy-accessed method is of great importance towards its practical applications.Herein,an evaporation induced self-assembly/carbonization(EISAC) method was developed and applied to the synthesis of sulfonic acid group functionalized mesoporous carbon(SMC).The final mesoporous carbon obtained by EISAC method possesses wormlike mesoporous structure,uniform pore size(3.6 nm),large surface area of 735 m²/g,graphitic pore walls and rich sulfonic acid group.Moreover,the resultant mesoporous carbon achieves a superior electrochemical capacitive performances(216 F/g)to phenolic resin derived mesoporous carbon(OMC,152 F/g)and commercial activated carbon(AC,119 F/g).     

Organophosphine/phosphite‐stabilized silver(I) complexes bearing N‐acetylbenzamide ligand: synthesis,characterization and potential application in metal organic chemical vapor deposition

New N‐silver(I) acetylbenzamide complexes of type L_n?AgNC₉H₈O₂ (L = PPh₃; n = 1, 2a; n = 2, 2b; n = 3, 2c; L = P(OEt)₃; n = 1, 2d; n = 2, 2e; n = 3, 2f) were prepared. These complexes were obtained in high yields and characterized by elemental analysis, ¹H NMR, ¹³C{H} NMR, ³¹P{H} NMR and IR spectroscopy, respectively. The molecular structure of 2b has been determined by X‐ray single‐crystal analysis in which the silver atom is in a distorted tetrahedral geometry and crystallizes as cis–trans. New N‐silver(I) acetylbenzamide complexes have a four‐membered ring, which could influence their chemical and physical properties and modulate volatility. Metal organic chemical vapor deposition experiments were carried out successfully at 400°C and 450°C using 2e as precursor for the deposition of silver films, respectively. The high‐purity silver film obtained at 400°C is dense and homogeneous. Copyright © 2012 John Wiley & Sons, Ltd.     

Palladium‐catalyzed Suzuki–Miyaura coupling with aryl and heteroaryl bromides using N,N,N′,N′‐tetra(diphenylphosphinomethyl)‐1,2‐ethylenediamine

An easily prepared tetraphosphine N,N,N′,N′‐tetra(diphenylphosphinomethyl)‐1,2‐ethylenediamine (1) combined with PdCl₂ affords an efficient catalytic system for Suzuki cross‐coupling of aryl and heteroaryl bromides. A high turnover number of 750 000 is obtained with the catalyst loading as low as 1 ppm. This catalyst system exhibits good stability and longevity. In this study, a broad scope of substrates is investigated and satisfactory yields are obtained. Copyright © 2012 John Wiley & Sons, Ltd.     

Gd complexes of diethylenetriaminepentaacetic acid conjugates of low-molecular-weight chitosan oligosaccharide as a new liver-specific MRI contrast agent

This study was to describe the synthesis of complexes of gadolinium diethylenetriaminepentaacetic acid conjugates of low-molecular-weight chitosan oligosaccharide Gd-DTPA-CSn (n = 6, 8, 11) as a new class of contrast agent as well as its magnetic property in a pilot magnetic resonance imaging. The efficacy of the contrast agent was assessed by measuring the longitudinal relaxivity (r₁), FLASH imaging in phantoms in vitro and signal intensity in vivo of the rat abdominal axial imaging. The r₁ of Gd-DTPA-CS₁₁ was up to 11.65 mM^− 1·s^− 1, which was 3 times higher than that of the analogous MRI contrast agent Gd-DTPA in commercial use. In vivo MR images of rat obtained with Gd-DTPA-CS₁₁ showed strong signal enhancement in liver and the vessels of the liver parenchyma during the extended period of time. The present study suggests that the new synthesized gadolinium complexes can be used as a new class of practical liver-specific MRI contrast agent because of its superior performance compared with Gd-DTPA.     

Highly rectified ion transport through 2D WSe2/MoS2 bi-layered membranes

Through a two-step vacuum-filtration process, WSe₂ and MoS₂ nanosheets were sequentially deposited onto a polymeric nanoporous support, forming WSe₂/MoS₂ bi-layered heterostructure. Highly rectified ion transport phenomenon is observed through the heterogeneous 2D layered membranes.     

Reduced matrix effects for anionic compounds with paired ion electrospray ionization mass spectrometry

It is well-known that matrix effects in high performance liquid chromatography coupled to electrospray ionization mass spectrometry (HPLC-ESI-MS) can seriously compromise quantitative analysis and affect method reproducibility. Paired ion electrospray ionization (PIESI) mass spectrometry is an approach for analyzing ultra-low levels of anions in the positive ion mode. This approach uses a structurally optimized ion pairing reagent to post-column associate with the anionic analyte, subsequently forming positively charged complexes. These newly formed complex ions are often more surface-active as compared to either the native anion or the ion pairing reagent. No studies have examined whether or not the PIESI approach mitigates matrix effects. Consequently, a controlled study was done using five analytes in highly controlled and reproducible synthetic groundwater and urine matrices. In addition, two different mass spectrometers (linear ion trap and triple quadrupole) were used. Compared to the negative ion mode, the PIESI-MS approach was less susceptible to matrix effects when performed on two different MS platforms. Using PIESI-MS, less dilution of the sample is needed to eliminate ionization suppression which, in turn, permits lower limits of detection and quantitation.