含平面手性和中心手性双手性因素化合物的合成及应用

[2,2]对二环苯经甲酰化、缩合、拆分得到（Rp）-4-甲酰基[2,2]对二环苯,再与L-亮氨酸的衍生物二齿手性氨基醇经缩合、还原得到由平面手性和中心手性因素构建的化合物（Rp,S）-1,1-二苯基-2-{[2,2]对二环苯基-甲氨基}-4-甲基戊醇.产物结构经IR、MS和1H NMR等进行了表征.用1H NMR考察了其作为主体对客体手性羧酸衍生物消旋体的手性识别能力.     

The preparation of nickel oxide based on infinite dilute method and its electrochemical performance

With NaOH as precipitation agent and NiSO₄ · 6H₂O as raw material, Ni(OH)₂ particles were synthesized by infinite dilute method and sintered at 300°C for NiO. The synthesized NiO particles with a structure of cubic crystalline phase are well dispersed and ball-flower like with a diameter of 500 nm. The electrochemical tests show that the NiO particles have relatively high capacitance and excellent capacitive retention. The good structure and excellent performance suggest its promising application in supercapacitors.     

Design and synthesis of pyromellitic diimide‐based donor–acceptor conjugated polymers for photovoltaic application

Three of conjugated polymers based on pyromellitic diimide (PMDI) as the acceptor unit and thienothiophene (TT) as the donor unit were successfully synthesized by Stille coupling. The effect of the side chain length and thiophene π‐bridge on the polymers' optical and electrochemical properties was investigated. Electrochemical characterization indicated that these polymers have deep highest occupied molecular orbital energy levels between ?5.7 and ?5.8 eV. Polymer solar cells were fabricated by using these PMDI‐based polymers as the donor and [6,6]‐phenyl‐C61‐butyric acid methyl ester as the acceptor. The polymer P1 whose PMDI unit was functionalized with 2‐ethylhexyl side chain shows the higher short‐circuit current (J_sc) and fill factor (FF) compared with that of P2 with a 2‐octyldodecyl side chain on the PMDI unit. The results also illustrate that the insertion of a thiophene π‐bridge between PMDI and TT (the polymer P3) leads to the broader absorption and better photovoltaic performance. The best performance was obtained from the cell based on the polymer P3 with a power conversion efficiency of 0.43% under the illumination of AM 1.5 G, 100 mW/cm². Copyright © 2014 John Wiley & Sons, Ltd.     

Peptide Dimethylation: Fragmentation Control via Distancing the Dimethylamino Group

Direct reductive methylation of peptides is a common method for quantitative proteomics. It is an active derivatization technique; with participation of the dimethylamino group, the derivatized peptides preferentially release intense a₁ ions. The advantageous generation of a₁ ions for quantitative proteomic profiling, however, is not desirable for targeted proteomic quantitation using multiple reaction monitoring mass spectrometry; this mass spectrometric method prefers the derivatizing group to stay with the intact peptide ions and multiple fragments as passive mass tags. This work investigated collisional fragmentation of peptides whose amine groups were derivatized with five linear ω-dimethylamino acids, from 2-(dimethylamino)-acetic acid to 6-(dimethylamino)-hexanoic acid. Tandem mass spectra of the derivatized tryptic peptides revealed different preferential breakdown pathways. Together with energy resolved mass spectrometry, it was found that shutting down the active participation of the terminal dimethylamino group in fragmentation of derivatized peptides is possible. However, it took a separation of five methylene groups between the terminal dimethylamino group and the amide formed upon peptide derivatization. For the first time, the gas-phase fragmentation of peptides derivatized with linear ω-dimethylamino acids of systematically increasing alkyl chain lengths is reported. Figure

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Comparison of cadmium manganese telluride crystals grown by traveling heater method and vertical Bridgman method

In this paper, the CdMnTe crystals were grown by the Travelling Heater Method (THM) and the Vertical Bridgman (VB) method, respectively. The crystal properties, including the Mn axial distribution, impurity concentrations, resistivity, Hall effects and energy response spectra, were characterized and compared. The results shown that the CdMnTe crystal grown by the THM had more uniform Mn distribution and lower impurity concentrations compared to the crystal grown by VB method. The resistivity of CdMnTe grown by THM was (1.5 ∼ 8) × 10¹⁰ Ω.cm, while the resistivity of CdMnTe grown by VB was 10⁷∼10⁸ Ω.cm. The In dopant distributed uniformly throughout the crystal ingot grown by THM with the doping concentration of 0.6–0.7 ppm, while the In dopant concentration throughout the crystal grown by VB method is in the range of 1.31–2.4 ppm. Hall measurements revealed that the conductivity of the THM grown crystal was weak n‐type conductivity and the VB grown crystal was p‐type conductivity. A planar CdMnTe detector from the THM grown crystal showed a resolution of 8% of the ²⁴¹Am radiation at 59.5 keV peak, however, no energy response was revealed with the CdMnTe detector by the VB method. The results demonstrate that CdMnTe crystal grown by THM have better crystal quality and detector properties compared to that by VB method.     

Physical and chemical studies on cement containing sugarcane molasses

Molasses is generally used as a grinding aid in cement and as a water reducer and retarder in concrete. In China, the output primarily consists of sugarcane molasses. In this paper, the effects of sugarcane molasses on the physical performance and hydration chemistry of conventional Portland cement were investigated. The setting times, the normal consistency of cement pastes, the compressive strengths and fluidities of the mortars were respectively determined according to Chinese Standard GB/T 1346, GB/T17671 and GB/T 2419. The effect of molasses on the hydration kinetics of cement was investigated using a calorimeter. The hydration products and pore size distribution of the cement pastes were analysed by X-ray powder diffraction, differential scanning calorimetry and a mercury injection apparatus. The results show that a small amount of sugarcane molasses retards the setting and hardening of cement paste and increases the fluidity of cement mortar, while excess molasses accelerates the setting and hardening. Molasses improves significantly the compressive strength at 3d due to the decrease of porosity. The addition of 1.0 % molasses accelerates the formation of ettringite, prevents the second hydration of aluminate phase and delays the hydration of C₃S.     

Green and facile synthesis of Pt/{PW12-GN} composite film and its electrocatalytic activity for methanol oxidation

In this paper, H₃PW₁₂O₄₀ (PW₁₂)-functionalized graphene nanosheets (PW₁₂-GNs) were prepared using a green and facile method via a UV-irradiated photoreduction process, in which PW₁₂ was directly deposited on the GNs as a reductant and also as an anionic stabilizer. The as-prepared water-dispersive PW₁₂-GN composite is used as matrices for electrodeposition of the interesting orchidlike Pt nanoclusters in situ. The PW₁₂-GN composite was characterized by transmission electron microscopy (TEM) and cyclic voltammetry (CV). It was shown that the electrochemical properties of PW₁₂ were maintained in PW₁₂-GNs. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) confirmed that Pt had been deposited on the PW₁₂-GN composite surface. Field emission scanning electron microscopy (FE-SEM) showed that the interesting orchidlike Pt nanoparticles were uniformly immobilized on the surface of the {PW₁₂-GN} composite film. Cyclic voltammetry and chronoamperometric curves were used to study the electrocatalytic activity of Pt/{PW₁₂-GN} regarding methanol oxidation in 0.5 M H₂SO₄. It is worthy of note that the Pt/{PW₁₂-GN} composite film-modified electrode presents a high catalytic activity (j?=?353 mA mg^?1) and better tolerance of CO towards methanol electrooxidation.     

Synthesis of polyaniline/Au composite nanotubes and their high performance in the detection of NADH

Polyaniline (PANI)/Au composite nanotubes were synthesized and developed as an electrode material for a nicotinamide adenine dinucleotide (NADH) sensor. A MnO₂ self-degradable template method was used to prepare the tube-like PANI nanomaterial. By introducing PANI nanotubes into Au colloid, Au nanoparticles (NPs) were successfully decorated onto the surface of PANI nanotubes through electrostatic effects. The morphology, composition, and optical properties of the resulting products were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-vis) absorption spectra, and thermogravimetric analysis (TGA). In addition, the obtained PANI/Au composites were used as catalysts for the electrochemical oxidation of NADH. Cyclic voltammogram (CV) experiments indicated that PANI/Au-modified glassy carbon electrode showed a higher electrocatalytic activity towards the oxidation of NADH in a neutral environment. Differential pulse voltammogram (DPV) results illustrated that the fabricated NADH sensor had excellent anti-interference ability and displayed a wide linear range from 4?×?10^?4 to 8?×?10^?3 M with a detection limit of 0.5?×?10^?7 M.     

Rhodium‐Catalyzed Ketone Methylation Using Methanol Under Mild Conditions: Formation of α‐Branched Products

The rhodium‐catalyzed methylation of ketones has been accomplished using methanol as the methylating agent and the hydrogen‐borrowing method. The sequence is notable for the relatively low temperatures that are required and for the ability of the reaction system to form α‐branched products with ease. Doubly alkylated ketones can be prepared from methyl ketones and two different alcohols by using a sequential one‐pot iridium‐ and rhodium‐catalyzed process.     

A Chiral Gold Nanocluster Au20 Protected by Tetradentate Phosphine Ligands

The chirality of a gold nanocluster can be generated from either an intrinsically chiral inorganic core or an achiral inorganic core in a chiral environment. The first structural determination of a gold nanocluster containing an intrinsic chiral inorganic core is reported. The chiral gold nanocluster [Au₂₀(PP₃)₄]Cl₄ (PP₃=tris(2‐(diphenylphosphino)ethyl)phosphine) has been prepared by the reduction of a gold(I)–tetraphosphine precursor in dichloromethane solution. Single‐crystal structural determination reveals that the cluster molecular structure has C₃ symmetry. It consists of a Au₂₀ core consolidated by four peripheral tetraphosphines. The Au₂₀ core can be viewed as the combination of an icosahedral Au₁₃ and a helical Y‐shaped Au₇ motif. The identity of this Au₂₀ cluster is confirmed by ESI‐MS. The chelation of multidentate phosphines enhances the stability of this Au₂₀ cluster.