Euphormins A and B, New Pyranocoumarin Derivatives from Euphorbia formosana Hayata, and Their Anti-Inflammatory Activity.

Euphormin-A (1) and euphormin-B (2), two new pyranocoumarin derivatives, and forty known compounds (3-42) were isolated from Euphorbia formosana Hayata (Euphorbiaceae). The chemical structures of all compounds were established based on spectroscopic analyses. Several isolates were evaluated for their anti-inflammatory activity. Compounds 1, 2, 10, 18, 25, and 33 significantly inhibited against superoxide anion generation and elastase release by human neutrophils in response to formyl-L-methionyl-L-leucyl-L-phenylalanine/cytochalasin B (fMLP/CB). Furthermore, compounds 25 and 33 displayed the most potent effects with IC50 values of 0.68 ± 0.18 and 1.39 ± 0.12 µM, respectively, against superoxide anion generation when compared with the positive control (2.01 ± 0.06 µM).

Creating a pseudometallic state of K+ by intercalation into 18-crown-6 grafted on polyfluorene as electron injection layer for high performance PLEDs with oxygen- and moisture-stable Al cathode.

Polymer light-emitting diodes (PLEDs) suffer from inadequate lifetimes because of the use of environmentally sensitive metals as the cathodes. We present the use of water/methanol-soluble polyfluorene grafted with 18-crown-6 chelating to K(+) as the electron-injection layer (EIL) for deep-blue-emission PLEDs, allowing the use of environmentally stable Al as the cathode since electron donation from the 18-crown-6 can reduce K(+) to a stable "pseudometallic state", enabling it to act as an intermediate step for electron injection. Furthermore, when poly(ethylene oxide) was blended into the EIL to provide hole blocking (HB), the device exhibited the highest performance reported to date for a deep-blue-emission PLED based on a conjugated polymer as the emitting layer, with a brightness of 54,800 cd/m(2) and an external quantum efficiency of 5.42%. The use of such an EI-HB layer opens a broad avenue leading toward industrialization of PLEDs.

Enhancing shielding of triplet energy transfer to poly(p-phenylene)s from phosphor dopant by addition of branched alcohol for highly efficient electrophosphorescence.

To obtain an efficient electrophosphorescent device, one needs to consider quenching of phosphor phosphorescence brought by the low triplet energy of the host because the exothermic energy transfer can effectively quench phosphor phosphorescence and markedly lower the device efficiency. Here, a facile approach of adding a branched alcohol (3-tert-butyl-2,2,4,4-tetramethylpentan-3-ol, ROH) into green emission phosphor-doped dialkoxyl-substituted poly(para-phenylene)s (PPPs) is demonstrated to effectively enhance shielding of triplet energy transfer to PPPs from the phosphor, resulting from a formation of self-assembly structure that block direct contact between phosphor and the main chains. The green electrophosphorescent device performance can be improved from 7.1 and 32.2 cd/A to 25.1 and 42 cd/A for PPP with dioctoxyl substituents (dC(8)OPPP) and with carbozole (Cz)-capped dialkoxyl-substituents (CzPPP), respectively. The latter result 42 cd/A is the highest record for green emission in polymer light emitting diode. This finding suggests that promotion of specific electro-optical properties for small molecule and polymer can be obtained through a self-assembling interaction in addition to chemical structure modification.