A series of novel styrene derived monomers with triphenylamine-based units, and their polymers have been synthesized and compared with the well-known structure of polymer of N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine with respect to their hole-transporting behavior in phosphorescent polymer light-emitting diodes (PLEDs). A vinyltriphenylamine structure was selected as a basic unit, functionalized at the para positions with the following side groups: diphenylamine, 3-methylphenyl-aniline, 1- and 2-naphthylamine, carbazole, and phenothiazine. The polymers are used in PLEDs as host polymers for blend systems with the following device configuration: glass/indium-tin-oxide/PEDOT:PSS/polymer-blend/CsF/Ca/ Ag. In addition to the hole-transporting host polymer, the polymer blend includes a phosphorescent dopant [Ir(Me-ppy)(3)] and an electron-transporting molecule (2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole). We demonstrate that two polymers are excellent hole-transporting matrix materials for these blend systems because of their good overall electroluminescent performances and their comparatively high glass transition temperatures. For the carbazole-substituted polymer (T-g = 246 degrees C), a luminous efficiency of 35 cd A(-1) and a brightness of 6700 cd m(-2) at 10 V is accessible. The phenothiazine-functionalized polymer (T-g = 220 degrees C) shows nearly the same outstanding PLED behavior. Hence, both these polymers outperform the well-known polymer of N,N'-bis(3-methylphenyl)-N,N'diphenylbenzidine, showing only a luminous efficiency of 7.9 cd A(-1) and a brightness of 2500 cd m(-2) (10 V)

We report the design and characterization of three heteroleptic orange-red phosphorescent iridium(III) complexes bearing two 2-(4-fluorophenyl)-3-methyl-quinoxaline (fpmqx) cyclometalated ligands combined with three different ancillary ligands, triazolylpyridine (trz), picolinate (pic), and acetylacetonate (acac). All of these complexes emit an orange to red color in the spectral range of 605-628 nm in dichloromethane. Strong spin-orbit coupling of the iridium atom allows the formally forbidden mixing of singlet and triplet states. Because of the structureless phosphorescent line shapes and low Stokes shifts between triplet metal-to-ligand charge-transfer ((3)MLCT) absorption and phosphorescent emission, we propose that emission originates predominantly from the (3)MLCT state with a lesser admixture of totally ligand-based (3)(pi-pi*) states. The influence of 5d-electron densities of the iridium center on highest occupied molecular orbitals leads to high emission quantum yields in toluene (Phi(p) = 0.39-0.42) and to short triplet lifetimes. Cyclovoltammetry measurements show reversible oxidation peaks from 0.74 to 0.92 V and reversible reduction waves with potentials ranging from -1.58 to -2.05 V versus Cp(2)Fe/Cp(2)Fe(+). All complexes have been applied in simple test devices and also in stable, long-living devices to evaluate their electroluminescent device performances, for which we especially report the influence of the chosen ancillary ligands on emission colors, efficiencies, and device lifetimes. We obtained narrowband emission ranging from 613 to 630 nm with a full width at half-maximum of 64-71 nm, and a maximum in power efficiency of eta(p) = 14.6 lm/W at a current density of J = 0.01 mA/cm(2) for [(fpmqx)(2)Ir(pic)]. The operating lifetimes of [(fpmqx)(2)Ir(trz)] in both neat and mixed matrixes were longer than that of the established stable tris(1-phenylisoquinolinato)iridium(III) [Ir(piq)(3)]. From the lifetime measurements, it becomes clear that the stability is strongly correlated to the type of ancillary ligand. An extrapolated lifetime of 58 000 h with an initial brightness of 1000 cd/m(2), together with a very low voltage increase of 0.2 V over a time period of 1000 h (starting voltage of 4.1 V), was achieved. Such a high device lifetime is attributed to the chemical stability of all materials toward both charge carriers and excitons.

A series of novel styrene functionalized monomers with phenylbenzo[d]imidazole units and the corresponding homopolymers are prepared. These side‐chain polymers show high glass‐transition temperatures that even exceed the corresponding value for the common electron‐transporting material 1,3,5‐tris(1‐phenyl‐1H‐benzo[d]imidazol‐2‐yl)benzene (TPBI). Similar electronic behavior between the polymers and TPBI is shown. The polymers are used as matrices for phosphorescent dopants. The fabricated devices exhibit current efficiencies up to 38.5 cd A−1 at 100 cd m−2 and maximum luminances of 7400 cd m−2 at 10 V with a minimum turn‐on voltage as low as 2.70 V in single‐layer devices with an ITO/PEDOT:PSS anode (ITO = indium tin oxide, PEDOT:PSS = poly(3,4‐ethylenedioxythiophene) doped with poly(styrenesulfonate)) and a CsF/Ca/Ag cathode.

SummaryTreatment of benzanthrone (1) with biphenyl-2-yl lithium leads to the surprisingly stable enol 4, which is converted by dehydrogenation into the benzanthrone derivative 7. Under acidic conditions 4 isomerises to the spiro compound 11 and the bicyclo[4.3.1]decane derivative 12. Furthermore, the formation of 7 and the hydrogenated compound 13 is observed. A mechanism for the formation of the reaction products is proposed and supported by DFT calculations.

In the title compound, [Ir(C11H6F2N)2(C22H17N4O)]·CH3OH, the coordination at iridium is essentially octa­hedral, but with distortions associated with the bite angles of the ligands [76.25 (9)–80.71 (12)°] and the differing trans influences of C and N ligands [Ir—N = 2.04 Å (average) trans to N but 2.14 Å trans to C]. All three bidentate ligands have coordinating ring systems that are almost coplanar [inter­planar angles = 1.7 (1)–3.8 (2)°]. The vinyl­benzyl group is disordered over two positions with occupations of 0.653 (4) and 0.347 (4). The methanol solvent mol­ecule is involved in a classical O—H⋯N hydrogen bond to a triazole N atom.