Benzene substituted with bipyridine and terpyridine as electron-transporting materials for organic light-emitting devices

New electron-transporting materials for organic light-emitting devices (OLEDs) based on trisubstituted benzene with both bipyridine and terpyridine, 1,3-bisbipyridyl-5-terpyridylbenzene (BBTB) and 1-bipyridyl-3,5-bisterpyridylbenzene (BTBB), were developed. Glass transition temperatures of BBTB and BTBB were 93 degrees C and 108 degrees C, respectively, and BTBB was completely amorphous with no melting point. Electron mobilities of BTBB exceeded the order of 10(-4) cm(2) V-1 s(-1), while those of BBTB were very high and reached 10(-3) cm(2) V-1 s(-1) at an electric field of approximately 500 kV cm(-2). These high mobilities contributed to a low voltage operation. For example, in the case of the conventional aluminum trisquinolinol (Alq)-based fluorescent OLED with BTBB, current densities of 3.5 mA cm(-2) and 100 mA cm(-2) were reached at voltages of 3.0 V and 4.5 V, respectively. In addition, ionization potentials of BBTB (6.33 eV) and BTBB (6.50 eV) were sufficiently large to confine holes in common emissive layers.ArticleJOURNAL OF MATERIALS CHEMISTRY. 22(14):6765-6773 (2012)journal articl

Benzene substituted with bipyridine and terpyridine as electron-transporting materials for organic light-emitting devices

New electron-transporting materials for organic light-emitting devices (OLEDs) based on trisubstituted benzene with both bipyridine and terpyridine, 1,3-bisbipyridyl-5-terpyridylbenzene (BBTB) and 1-bipyridyl-3,5-bisterpyridylbenzene (BTBB), were developed. Glass transition temperatures of BBTB and BTBB were 93 degrees C and 108 degrees C, respectively, and BTBB was completely amorphous with no melting point. Electron mobilities of BTBB exceeded the order of 10(-4) cm(2) V-1 s(-1), while those of BBTB were very high and reached 10(-3) cm(2) V-1 s(-1) at an electric field of approximately 500 kV cm(-2). These high mobilities contributed to a low voltage operation. For example, in the case of the conventional aluminum trisquinolinol (Alq)-based fluorescent OLED with BTBB, current densities of 3.5 mA cm(-2) and 100 mA cm(-2) were reached at voltages of 3.0 V and 4.5 V, respectively. In addition, ionization potentials of BBTB (6.33 eV) and BTBB (6.50 eV) were sufficiently large to confine holes in common emissive layers.ArticleJOURNAL OF MATERIALS CHEMISTRY. 22(14):6765-6773 (2012)journal articl

Iron-catalyzed intramolecular cyclotrimerization of triynes to annulated benzenes

An iron species derived from FeCl2 or FeCl3 by in situ reduction with zinc powder in the presence of imidazol-2-ylidene or bidentate nitrogen ligand could effectively catalyze intramolecular cycloisomerization of triynes to annulated benzenes. With a 2-iminomethylpyridine ligand, hydrates of FeCl2 and FeCl3 as well as their anhydrous ones could be used

Allylic substitution reactions with Grignard reagents catalyzed by imidazolium and 4,5-dihydroimidazolium carbene–CuCl complexes

Imidazolium and 4,5-dihydroimidazolium carbene–CuCl complexes effectively catalyzed the substitution reaction of allylic compounds with Grignard reagents in an SN2′-selective fashion. It was noteworthy that the amount of the imidazolium carbene-CuCl complex could be reduced to 0.001 mol% and the catalysis recorded a high TON (105). Based on the experimental results, the ate-type complex(es) such as [(imidazolium carbene)-CuR2]−(MgX)+ was postulated as an active species

Selective dimerization of 1,6-diynes catalyzed by ionic liquid-supported nickel complexes in an ionic liquid/toluene biphasic system

A NiCl2-6H2O/Zn reagent with a 2-aryliminomethylpyridine ligand catalyzed cyclization/polymerization of 1,6-diynes mainly 10 to yield the corresponding poly(1,3-butadienylene) compounds, whereas, NiBr2-3H2O/Zn with use of 3-(2-(2 -methoxyethoxy)- ethyl)-1-methyl-1H-imidazol-3-ium bromide as a ligand converted 1,6-diynes to the corresponding annulated 1,3,5,7-cyclooctatetraenes in a biphasic solvent system consisting of 15 toluene and an ionic liquid.http://pubs.rsc.org/en/Content/ArticleLanding/2009/CC/B816850