NARROW BANDWIDTH BRIGHT SCARLET ORGANIC ELECTROLUMINESCENT DEVICE BASED ON N,N'-BIS[4-(N,N-DIMETHYLAMONO)-BENZYLIDENE]-DIAMINOMALEONITRILE DYE

A novel red dye, N, N'-bis[4-(N,N-dimethylamino)-benzylidene]diaminomaleonitrile (BAM), was prepared by reacting diaminomaleonitrile with 4-(N,N-dimethylamino)-benzaldehyde and were characterized by ¹H NMR, UV absorption and photoluminescence. The BAM dye showed an absorption peak wavelength of 530 nm and bright photoluminescence with a peak wavelength at 675 nm. It was used as the doped emitter for fabricating a bright scarlet organic electroluminescent (EL) device. The structure of the double-layer EL device consisted of a hole-transport layer and a luminescent layer between ITO glass and magnesium electrodes. The hole-transport layer was a poly(N-vinylcarbazole) (PVK) film. The luminescent layer consisted of a host material, 8-hydroxyquinoline aluminum (Alq₃), and BAM dye as the dopant. A bright light with the peak of 620 nm and narrow bandwidth of 50 nm was obtained in the device with a maximum luminance of 6230 cd/m². The emission spectra almost unchanged as the luminance increased with increasing injection current and the bias voltage. A tentative explanation from both the electronic distribution viewpoint and the molecular geometric analysis for the narrow bandwidth of this red dye was offered.     

Synthesis,characterization and catalytic performance of nanosized iron-cobalt catalysts for light olefins production

Nanosized Fe-Co catalysts were prepared by co-precipitation method and studied for the conversion of synthesis gas to light olefins.In particular,the effects of a range of preparation variables such as Co/Fe molar ratios of the precipitation solution,pH value of precipitate,temperature of precipitation,promoters and loading of optimum promoter on the structure and catalytic performance are investigated.The optimal nano catalyst for light olefins (C2-C4) production was obtained over the catalyst with Co/Fe molar ratio of 3/1 which promoted with 2 wt% K.The results show that the best operational conditions were GHSV=2200 h-1 (H2/CO=2/1) at 260℃ under atmospheric pressure.Characterization of catalysts were carried out using X-ray diffraction (XRD),thermal gravimetric analysis (TGA),differential scanning calorimetry (DSC),scanning electron microscopy (SEM),transmission electron microscopy (TEM) and N2 physisorption measurements such as Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods.     

Behavior of metal complexes of polyacrylic acid in solutions

Metal complexes of polyacrylic acid containing Li, Li, and Cu, or Li and Zn have been studied in saline aqueous solutions using molecular hydrodynamics and light scattering methods. Intrinsic viscosities, weight-average molar masses, hydrodynamic radii, and radii of gyration were obtained. It was shown that the macromolecules of polymetalloacrylates containing divalent metals form small and large supramolecular structures, their dimensions, and composition being dependent on the ionic strength of the solution.     

等离子体光谱光源技术的进展

光谱光源是光谱仪器和光谱技术的核心,等离子体光源是原子发射光谱技术的活跃领域之一,电感耦合等离子体(ICP)已成功地应用于原子发射光谱和无机质谱仪器。由于ICP光源采用氩气作为工作气体,耗量较大,降低氩气用量成为近些年来原子光谱技术研究和改进的重要目标。为此目的,已研究过各种低耗氩ICP光源,非氩气ICP光源,微波等离子体光源,射频电容耦合等离子体光源等。综述了近年这些等离子体发射光源的结构,分析性能及特点,以及它们所用工作气体情况。并归纳总结出,评价各种等离子体发射光谱光源应包括:等离子体温度(激发温度,气体温度),电子密度,工作气体种类及用量,元素检出限,光源的稳健性及经济方面等。     

CoII Cryptates Convert CO2 into CO and CH4 under Visible Light

Three Co^II octaazacryptates, with different substituents on the aromatic rings (Br, NO₂, CCH), were synthesised and characterised. These and the already published non-substituted cryptate catalysed CO₂ photoreduction to CO and CH₄ under blue visible light at room temperature. Although CO was observed after short irradiation times and a large range of catalyst concentrations, CH₄ was only observed after longer irradiation periods, such as 30 h, but with a small catalyst concentration (25 nm ). Experiments with ¹³C labelled CO₂ showed that CO is formed and reacts further when the reaction time is long. The CCH catalyst is deactivated faster than the others and the more efficient catalyst for CH₄ production is the one with Br. This reactivity trend was explained by an energy decomposition analysis based on DFT calculations.     

Synthesis of Cyclic Compounds via Photoinduced Radical Cyclization Cascade of C=C bonds

Cyclic compounds constitute a great important class of substances in the science of medicine and biology, which renders the research on facile and efficient construction of such complex scaffolds from simple starting materials to be hot and appealing. Recently, the radical cascade reaction involving multiple bond formation/cleavage has emerged as an ideal and powerful route to give high‐value cyclic products, along with diminished cost and waste. As a simple and benign methodology, photoredox catalysis offers a readily available access to the generation of radical species. Alkenes have been recognized as one of the most valuable building blocks for the reason they allow installation of different functional groups simultaneously through addition to the C=C bonds. This account summarizes the recent advances in photoinduced radical cascade cyclization to the synthesis of cyclic compounds with C=C bonds working as the initial radical acceptors, and emphasis is put on the related reaction mechanisms.     

Development of new high‐performance visible light photoinitiators based on carbazole scaffold and their applications in 3d printing and photocomposite synthesis

In this article, new compounds based on the carbazole scaffold (DMs = DM1 and DM2, constituted by a carbazole unit connected on positions 3 and 6 to a two 4,4′‐dimethoxydiphenylamine groups and differing by the substituent present on the nitrogen heteroatom of the carbazole core) were synthesized and proposed as high‐performance visible light photoinitiators/photosensitizers for both the free‐radical polymerization of methacrylates and the cationic polymerization of epoxides upon visible light exposure using LED@405 nm. Remarkably, DM2 leads to higher final conversions than DM1. In order to study the photophysical and photochemical properties of the carbazole derivatives, different parameters were taken into account such as the light absorption, the steady‐state photolysis, and the fluorescence spectroscopy. Using different techniques such as fluorescence quenching, redox behavior, and cyclic voltammetry, we are able to discuss the photosensitization/photoinitiation reactions providing a full coherent picture of the involved chemical mechanisms. The photosensitization of the carbazole derivatives occurred predominantly via singlet excited states at the rate of the diffusion limit. Upon exposure to laser diode at 405 nm, DMs show high performance in initiating systems for 3D resins. Remarkably, DM2 can also be used in photocomposite synthesis using light‐emitting diode conveyor. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2081–2092     

Photocatalysed eosin Y mediated C(sp3)-H alkylation of amine substrates via direct HAT

A visible light promoted, photoredox catalysed, green one-pot approach for the alkylation of amine substrates with sp² carbon has been developed. This eosin Y based organic transformations, can behave as an effective direct hydrogen-atom transfer catalyst for coupling reaction. The proposed strategy includes simple procedure which can make adduct product with sp² carbon. This eosin Y based photocatalytic hydrogen-atom transfer strategy may hold great potential for diverse functionalization of a wide range of native CH bonds in an economical and sustainable manner.     

二氧化钛包裹金纳米棒核壳材料的制备及其光解水制氢

利用溶胶凝胶法制备了金纳米棒(GNR)与TiO₂的核壳结构复合材料--GNR@TiO₂,粒径为200 nm左右。 经水热晶化后的材料粒径为300 nm左右,GNR形貌和局域表面等离子共振(LSPR)峰保持稳定,其外边包裹着树枝状的锐钛矿相TiO₂壳层。 采用X射线衍射(XRD)、高分辨透射电子显微镜(HRTEM)、X射线光电子能谱分析(XPS)、紫外可见吸收光谱、光催化制氢性能等技术手段测试表征了样品的结构及性能。 结果表明,晶化后的GNR@TiO₂在可见光范围内制氢速率为31.0 μmol/(g·h),相较与晶化前7.3 μmol/(g·h)得到了明显提升。 最后结合实验结果和时域有限差分(FDTD)分析了催化产氢机理:LSPR促进了可见光吸收,锐钛矿TiO₂对电场的增强促进了光生电子-空穴分离,同时晶化后的TiO₂壳层疏松多介孔,增加了活性位点,有利于传质。     

Microfluidic Device Using a Gold Pillar Array and Integrated Electrodes for On‐chip Endothelial Cell Immobilization,Direct RBC Contact,and Amperometric Detection of Nitric Oxide

We describe a microfluidic device that can be used to detect interactions between red blood cells (RBCs) and endothelial cells using a gold pillar array (created by electrodeposition) and an integrated detection electrode. Endothelial cells can release nitric oxide (NO) via stimulation by RBC‐derived ATP. These studies incorporate on‐chip endothelial cell immobilization, direct RBC contact, and detection of NO in a single microfluidic device. In order to study the RBC‐EC interactions, this work used a microfluidic device made of a PDMS chip with two adjacent channels and a polystyrene base with embedded electrodes for creating a membrane (via gold pillars) and detecting NO (at a glassy carbon electrode coated with platinum‐black and Nafion). RBCs were pharmacologically treated with treprostinil in the absence and presence of glybenclamide, and ATP release was determined as was the resultant NO release from endothelial cells. Treprostinil treatment of RBCs resulted in ATP release that stimulated endothelial cells to release on average 1.8±0.2 nM NO per endothelial cell (average±SEM, n=8). Pretreatment of RBCs with glybenclamide inhibited treprostinil‐induced ATP release and, therefore, less NO was produced by the endothelial cells (0.92±0.1 nM NO per endothelial cell, n=7). In the future, this device can be used to study interactions between many other cell types (both adherent and non‐adherent cell lines) and incorporate other detection schemes.