Composition and mode of occurrence of minerals in Late Permian coals from Zhenxiong County,northeastern Yunnan,China

Minerals in the Late Permian coals from the Niuchang-Yigu mining area,Zhenxiong County,northeastern Yunnan,China,were investigated using optical microscopy and low temperature ashing plus X-ray diffraction(LTA?XRD).The results showed that minerals in the coal LTAs are mainly quartz,kaolinite,chamosite,mixed-layer illite/smectite(I/S),pyrite,and calcite,with trace amounts of marcasite,dolomite,and bassanite.The authigenic quartz generally occurs in collodetrinite or as a filling in cleats or cell cavities.This silica was mainly derived from aqueous solutions produced by the weathering of basaltic rocks in the Kangdian Upland and from hydrothermal fluids.The presence of b-quartz paramorph grains in collodetrinite probably indicates that these grains were detrital and came from a volcanic ash.Clay minerals are generally embedded in collodetrinite and occur as cell-fillings.Pyrite occurs as framboidal,anhedral,and euhedral grains and a cell-filling.The coals are high in pyrite and the high pyrite content probably results from seawater invading during the stage of peat accumulation.Calcite generally occurs as vein-fillings,indicating an epigenetic origin.

Extremely high-efficiency and ultrasimplified hybrid white organic light-emitting diodes exploiting double multifunctional blue emitting layers

Numerous hybrid white organic light-emitting diodes(WOLEDs)have recently been developed.However,their efficiency is not comparable to that of their best all-phosphorescent WOLED counterparts,and the structures are usually complicated,restricting their further development.Herein,a novel concept is used to achieve a hybrid WOLED,whose crucial feature is the exploitation of double multifunctional blue emitting layers.The three-organic-layer WOLED exhibits a total efficiency of 89.3 and 65.1 lm W^(-1) at 100 and 1000 cd m^(-2),respectively,making it the most efficient hybrid WOLED reported in the literature so far.Significantly,the efficiencies of hybrid WOLEDs have,for the first time,been demonstrated to be comparable to those of the best all-phosphorescent WOLEDs.In addition,the device exhibits the lowest voltages among hybrid WOLEDs(i.e.,2.4,2.7 and 3.1 V for 1,100 and 1000 cd m^(-2),respectively).Such remarkable performance achieved from such an ultrasimplified structure opens a new path toward low-cost commercialization.

Molecular engineering of an electron-transport triarylphosphine oxide-triazine conjugate toward high-performance phosphorescent organic light-emitting diodes with remarkable stability

Organic electron-transport materials are an essential component to boost performances and stability of organic light-emitting diodes. We present a robust organic electron-transport compound 3-(6-(3-(4,6-bis(4-biphenylyl)-1,3,5-triazin-2-yl)phenyl)pyridin-2-yl)phenyldiphenylphosphine oxide by facilely coupling the triphenylphosphine oxide moiety to the 2-phenyl-4,6-bis(4-biphenylyl)-1,3,5-triazine unit via a 2,6-pyridinylene linker. It is well soluble in weakly polar solvents and possesses a high Tg of 123 ℃ with an exceptional Td≈470 ℃ at 1% weight loss and deep HOMO/LUMO levels of ca.-6.45/-3.06 eV. The phosphorescent spectrum measured in solid state at 77 K reveals a notable triplet energy of 2.88 eV. n-Doping with 8-hydroxyquinolatolithium(Liq) produces the electron mobility value of 4.66×10-5–3.21×10-4 cm2 V-1 s-1@(2–5)×105 V cm-1.Moreover, the contrasting solubility of the bromo reaction intermediate and the new compound in alcoholic solvents facilitates separation. The characterizations of bottom-and top-emission green phosphorescent OLEDs involving this single Liq-doped electron-transport layer reveal long stability. In particular, the latter provides outstanding performances with 77.4 cd A–1(corresponding to an EQE of 18.7%) and 86.8 lm W–1@ca. 1000 cd m-2, based on the green emitter bis(2-phenylpyridine)(2-(4-methyl-3-phenylphenyl)pyridine)iridium(Ⅲ). Moreover, driven by a constant current for ca. 640 h, the initial luminance of 1000 cd m–2 appears almost no decay.

Phenolic compounds isolated from Pilea microphylla prevent radiation-induced cellular DNA damage

Six phenolic compounds namely,quercetin-3-O-rutinoside(1),3-O-caffeoylquinic acid(2),luteolin-7-O-glucoside(3),apigenin-7-O-rutinoside(4),apigenin-7-O-b-D-glucopyranoside(5)and quercetin(6)were isolated from the whole plant of Pilea microphylla using conventional opensilica gel column chromatography and preparative HPLC.Further,these compounds were characterized by 1D,2D NMR techniques and high-resolution LC–MS.Compounds 1–3 and 6 exhibited significant antioxidant potential in scavenging free radicals such as DPPH,ABTS and SOD with IC_(50) of 3.3–20.4 mmol/L.The same compounds also prevented lipid peroxidation with IC_(50) of 10.4–32.2 mmol/L.The compounds also significantly prevented the Fenton reagent-induced calf thymus DNA damage.Pre-treatment with compounds 1–3 and 6 in V79 cells attenuated radiation-induced formation of reactive oxygen species,lipid peroxidation,cytotoxicity and DNA damage,correlating the antioxidant activity of polyphenols with their radioprotective effects.Compounds 1,3 and 6 significantly inhibited lipid peroxidation,presumably due to 30,40-catechol ortho-dihydroxy moiety in the B-ring,which has a strong affinity for phospholipid membranes.Oxidation of flavonoids,with catechol structure on B-ring,yields a fairly stable ortho-semiquinone radical by facilitating electron delocalization,which is involved in antioxidant mechanism.Hence,the flavonoid structure,number and location of hydroxyl groups together determine the antioxidant and radioprotection mechanism.

Rubratoxin C,a new nonadride derivative from an endophytic fungus Penicillium sp.F-14

One new nonadride derivative rubratoxin C （1） together with a known compound rubratoxin B （2） were isolated from an endophytic fungus Penicillium sp. F-14. Their structures were elucidated by various spectroscopic methods. Bioassays showed that 2 had moderate cytotoxic effect against HCT-8, BEL-7402, Ketr3, A2780, MCF-7 and BGC-823 human cancer cell lines, and 1 exhibited weak activity.

Appending triphenyltriazine to 1,10-phenanthroline: a robust electron-transport material for stable organic light-emitting diodes

There has been an increasing demand for high-performance and cost-effective organic electron-transport materials for organic light-emitting diodes （OLEDs）. In this contribution, we present a simple compound 3-（3-（4,6-diphenyl-l,3,5-triazin-2-yl）phenyl）-1,10-phenanthroline through the facile Pd-catalyzed coupling of a triphenyltriazine boronic ester with 3-hromo-1,10-phenanthroline. It shows a high Tg of 112℃. The ultraviolet photoelectron spectroscopy measurements reveal a deep HOMO level of -6.5 eV. The LUMO level is derived as -3.0 eV, based on the optical bandgap. The low-temperature solid-state phosphorescent spectrum gives a triplet energy of -2.36eV. n-Doping with 8-hydroxyquinolatolithium （Liq, 1：1） leads to considerably improved electron mobility of 5.2 × 10 -6 -5.8 × 10 -5 cm2 v-1 S-1 at E=（2-5） × 10 5Vcm -1, in contrast with the triarylphosphine oxide- phenantroline molecular conjugate we reported previously. It has been shown that through optimizing the device structure and hence suppressing polaron-exciton annihilation, introducing this single Liq-doped electron-transport layer could offer high-efficiency and stable phosphorescent OLEDs.