Cover picture : a concise method for synthesizing 1,4,8,11-tetraaza-6,13-dioxapentacene derivatives (Asian J. Org. Chem. 10/2013)

Five substituted tetraazadioxaacenes have been synthesized through the condensation of 2,3,7,8-tetraaminodibenzo-1,4-dioxin tetrahydrochloride and diketones. In their Full Paper on page 852 ff., Qichun Zhang and co-workers shown that these linearly extended molecules have relatively large bandgaps, and some of the compounds have less negative reduction potentials than is predicted by calculations

Mesoporous Ni_0.85Se Nanospheres Grown in Situ on Graphene with High Performance in Dye-Sensitized Solar Cells

Mesoporous Ni_0.85Se nanospheres grown on graphene were synthesized via the hydrothermal approach. Because of the exceptional electron-transfer pathway of graphene and the excellent catalytic ability of the mesoporous Ni_0.85Se nanospheres, the nanocomposites exhibited excellent electrocatalytic property as the counter electrode (CE) of dye-sensitized solar cells. More catalytic active sites, better charge-transfer ability and faster reaction velocity of Ni_0.85Se@RGO (RGO = reduced graphene oxide) CE led to faster and more complete I₃^– reduction than Pt, Ni_0.85Se, and RGO CEs. Furthermore, the power conversion efficiency of Ni_0.85Se@RGO CE reached 7.82%, which is higher than that of Pt CE (7.54%). Electrochemical impedance spectra, cyclic voltammetry, and Tafel polarization were obtained to demonstrate positive synergetic effect between Ni_0.85Se and RGO, as well as the higher catalytic activity and the better charge-transfer ability of Ni_0.85Se@RGO compared with Pt CE

Use of polyfunctionalized ethylene synthons: Convenient synthesis of biologically active trifluoromethyl containing N-substituted<b style="">-</b>benzoylpyrazoles and triazole

483-488Ten biologically active trifluoromethyl containing N-substituted-benzoylpyrazoles (3a-d, 4a-d, and 6a, b) and one triazole analogue 5 have been conveniently synthesized from four versatile polyfunctionalized ethylene synthons and one novel synthon N-cyanoimido-S,S- dimethyldithio-carbonate (CIDT, v), respectively. The reactions of trifluoromethyl containing substituted benzoylhydrazine with classical synthons such as ethyl dimethylaminomethylene- malonate, acetylacetone and ethyl acetoacetate have also been investigated. Herbicidal, fungicidal and plant-growth regulation activities for all reported new compounds have been determined and reported

Peripheral cyanohexyl substituent in wide bandgap polymer: Increase the electron injection property for blue phosphorescence light emitting device

Novel blue phosphor host, PCNCzSi, using 3,6-linked carbazole with δ-π tetraphenylsilane segment as the main chain modified by peripheral cyanohexyl group was designed. The Si-carbazole backbone entitles the polymer with wide bandgap, high E T and good hole transporting ability. The introduction of peripheral CN group with high electron affinity enhances the electron injecting property of the polymer revealed by electron-only device and UPS measurement. Highly efficient spin-coated phosphorescent polymer light-emitting device, using PCNCzSi as the host for blue iridium complex, FIrpic, was realized. The maximum luminous efficiency and maximum external quantum efficiency of the device were 15 cd/A and 6.7%, respectively, which are very high values for blue phosphorescent device using polymers as hosts as known. Cyano group, which possesses strong electron-withdrawing property, was attached on the hexyl side chain to obtain wide band gap polymer, PCNCzSi. Highly efficient spin-coated phosphorescent polymer light-emitting device, using PCNCzSi as the host for blue iridium complex FIrpic was prepared, and the maximum luminous efficiency and maximum external quantum efficiency of the devices were reached to 15 cd/A and 6.7%, respectively. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.Link_to_subscribed_fulltex

Differences in Leukocyte Telomere Length between Coronary Heart Disease and Normal Population: A Multipopulation Meta-Analysis

Coronary heart disease (CHD) is one of the most common causes of death in the world. Numerous studies have shown that as the degree of atherosclerotic disease increases, leukocyte telomere length gradually decreases. Short telomeres increase the risk of all-cause death and cardiovascular death. However, the reported results are not consistent, since the experimental design method, the measurement method, and the disease outcome are different. Therefore, we searched five major literature databases (Pubmed, Web of science, Embase, CNKI, and Wangfang) and finally included 18 eligible articles (including 5,150 patients with CHD and 9341 controls). We found that telomere length in patients with CHD was significantly shorter than that in controls, and the telomere length was inversely correlated with the severity of CHD. Subgroup analysis showed that telomere shortening was the most significant in Asian patients with CHD, in CHD patients with an average age <65 years, and in men with CHD. The mechanism of shortening the telomere length leading to the occurrence and development of CHD is worthy of further study

A highly efficient, blue-phosphorescent device based on a wide-bandgap host/FIrpic: Rational design of the carbazole and phosphine oxide moieties on tetraphenylsilane

A new series of wide-bandgap materials, 4-dipenylphosphine oxide-4'-9H-carbazol-9-yl-tetraphenylsilane (CSPO), 4-diphenylphosphine oxide-4',4″-di(9H-carbazol-9-yl)-tetraphenylsilane (pDCSPO), 4-diphenylphosphine oxide -4'-[3-(9H-carbazol-9-yl)-carbazole-9-yl]- tetraphenylsilane (DCSPO), 4-diphenylphosphine oxide-4',4″,4″'- tri(9H-carbazol-9-yl)-tetraphenylsilane (pTCSPO) and 4-diphenylphosphine oxide -4'-[3,6-di(9H-carbazol-9-yl)-9H-carbazol-9-yl]-tetraphenylsilane (TCSPO), containing different ratios and linking fashions of p-type carbazole units and n-type phosphine oxide units, are designed and obtained. DCSPO is the best host in FIrpic-doped devices for this series of compounds. By utilizing DCzSi and DPOSi as hole- and electron-transporting layers, a high EQE of 27.5% and a maximum current efficiency of 49.4 cd A -1 are achieved in the DCSPO/FIrpic doped device. Even at 10 000 cd m -2, the efficiencies still remain 41.2 cd A -1 and 23.0%, respectively. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.Link_to_subscribed_fulltex

Crystal structure and phototransistor behavior of N-substituted heptacence

6,8,15,17-Tetraaza-1.18,4.5,9.10,13.14-tetrabenzoheptacene (TTH, 1) has been prepared and characterized by single-crystal X-ray structure analysis. A phototransistor device based on TTH single crystal demonstrated that TTH showed a good performance in signal amplification under the photoconductive effect as well as photocontrolled switches

Synthesis and Nonvolatile Memory Behaviors of Dioxatetraazapentacene Derivatives

Two novel heteroacenes 2,3,9,10-tetra­(furan-2-yl)-1,4,8,11-tetraaza-6,13-dioxapentacene (<b>FAOP</b>, <b>1</b>) and 2,3,9,10-tetra­(thiophen-2-yl)-1,4,8,11-tetraaza-6,13-dioxapentacene (<b>TAOP</b>, <b>2</b>) was successfully synthesized through a one-step condensation reaction, which have been fully characterized by ¹H NMR (nuclear magnetic resonance), ¹³C NMR, FT-IR (Fourier transform infrared spectroscopy), and HRMS (high-resolution mass spectrum). The sandwich-structure memory devices have been fabricated using <b>FAOP</b> (<b>1</b>) and <b>TAOP</b> (<b>2</b>) as active layers, showing a typical bipolar resistive switching (RS) behavior in positive and negative regions

Doped Organic Crystals with High Efficiency, Color-Tunable Emission toward Laser Application

Doping an organic crystal such as an inorganic semiconductor without having a bad influence on crystalline quality is a very difficult task because weak intermolecular interactions and lattice mismatches exist in organic condensed states. We report here the successful growth of tetracene and pentacene-doped trans-1,4-distyrylbenzene (trans-DSB) crystals with high crystalline quality, large size, and excellent optical properties. The doped concentration up to 10% can be achieved by controlling the temperature of the crystal growth zone. The first key point for the crystals with a high doping ratio is the choice of the host (trans-DSB) and guest (tetracene or pentacene) molecules with comparable crystal lattice structures, which ensure less lattice mismatch. The second key point is crystal growth at relative high temperatures by the physical vapor transport (PVT) method, which gives the guest molecules high kinetic energy to incorporate into the crystal lattice of the host. These doped crystals with slice shape and large size (millimeter scale) maintain ordered layer structures and crystal surface continuities, which are verified by X-ray diffraction (XRD) and atomic force microscopy (AFM) analysis. Efficient energy transfer from the host to the guest and the suppressing of the interaction among the guest molecules lead to color-tunable emission and high luminescent efficiencies (blue for undoped trans-DSB, η = 65 ( 4%; green for tetracene-doped trans-DSB, η = 74 ( 4%; red for pentacenedoped trans-DSB, η = 28 ( 4%). Steady-state and time-resolved fluorescence spectroscopy of undoped and doped crystals, and their amplified spontaneous emissions, have been investigated. These doped crystals are expected to be of interest for lightemitting transistors, diodes, and electrically pumped lasers