6-N,N-diphenylaminobenzofuran-derived pyran containing fluorescent dyes: a new class of high-brightness red-light-emitting dopants for OLED.

Dye-doped organic light-emitting diode of ITO/alpha-NPB (70 nm)/Bebq(2)-1 (7 nm)/BCP (5 nm)/Bebq(2) (33 nm)/LiF (1 nm)/Al (150 nm) shows red electroluminescence with the efficiency of 2.9 cd/A at 100 cd/m(2) and maximum brightness of 62000 cd/m(2). The physical organic aspects of the current-induced fluorescent quenching effect are discussed. [structure: see text]

Photophysical and electrochemical properties of 1,7-diaryl-substituted perylene diimides.

Substituent effects on the photophysical and electrochemical properties of 1,7-diaryl-substituted perylene diimides (1,7-Ar(2)PDIs) have been carefully explored. Progressive red-shifts of the absorption and emission maxima were observed when the electron-donating ability of these substituents was increased. Linear Hammett correlations of 1/lambda(max) versus sigma(+) were observed in both spectral analyses. The positive slopes of the Hammett plots suggested that the electronic transitions carry certain amounts of photoinduced intramolecular charge-transfer (PICT) character from the aryl substituents to the perylene diimide core which leads to the reduction of the electron density on the substituents. The substituent electronic effects originated mainly from the perturbation of the core PDI HOMO energy level by the substituents. This conclusion was supported by PM3 analyses and confirmed by cyclic voltammetry experiments. More interestingly, the Ph(2)NC(6)H(4)-substituted PDI, 4i, showed an unusual dual-band absorption that spans from 450 to 750 nm. We tentatively assigned these two bands as the charge-transfer band and the PDI core absorption, respectively.

Synthesis and spectroscopic properties of finite Ph2N-containing oligo(arylenevinylene) derivatives that emit blue to red fluorescence.

[structure: see text] A series of oligo(phenylenevinylene) (OPV) derivatives with finite conjugation units were prepared in short steps from few building blocks. The central and terminal aryl groups of these OPV dyes contain cyano and Ph(2)N substituents, respectively, which affect color of fluorescence. The wavelength ranges from 472 nm (blue) to 614 nm (red) depending on the position of the cyano group.

Tungsten-Mediated Syntheses of Fused alpha-Methylenebutyrolactones from Propargyl Bromides Containing Tethered Aldehydes and Ketones.

The reaction of CpW(CO)(3)Na with a number of propargyl bromides with tethered aldehydes and ketones afforded eta(1)-propargyl species that were subsequently transformed into tungsten-eta(3)-2-(methoxycarbonyl)allyl compounds upon treatment with p-TSA/CH(3)OH; the overall yields exceeded 60%. Sequential treatment of these tungsten-eta(3)-allyl complexes with NOBF(4) and NaI in CH(3)CN led to intramolecular allyltungsten-carbonyl cyclization, yielding fused alpha-methylene butyrolactones of five-, six-, and seven-membered carbocyclic rings. All the reactions proceeded with high diastereoselectivities except for 9-methylene-7-oxabicyclo[4.3.0]nonan-8-one (22) and 10-methylene-8-oxabicyclo[5.3.0]decan-9-one (23). Modification of the metal center with a chloride ligand led to significant improvement of the trans-stereoselection of 22; the chloride modification did not significantly enhance stereoselection of 23. The stereochemical course of the reaction products is rationalized on the basis of a bicyclic transition-state mechanism.