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Organic light-emitting devices (OLEDs) hold great potential for application in flat-panel displays due to rapid progress in material design and device fabrication in recent years. [1±4] Red, green, and blue emissions of matching efficiencies are required for a full-color display. Greater success has been achieved in the development of a green emitter than that of red one in both fluorescent and phosphorescent displays. For example, devices based on green fluorescent dopant C545T [5] can reach a luminance efficiency > 10 cd A ±1 . In contrast, the best red OLEDs reported [6±10] can only reach~3 cd A ±1 and external quantum efficiencies less than 1 %. OLEDs based on phosphorescent materials [11] can significantly improve electroluminescence performance because both singlet and triplet excitons can be harvested for light emission. Theoretically, the internal quantum efficiency of phosphorescent emitters can approach 100 %. Unfortunately, most of phosphorescent emitters have a long lifetime (> 10 ls), which results in saturation of emissive sites at increasing currents. The first red phosphorescent material was reported for complexes of the type EuL 3 , where L denotes a ligand.[12] The long lifetime of the electronically excited europium(III) (350 ls) leads to dominant triplet±triplet (T±T) annihilation at high currents, and the maximum efficiency is only 1.4 %. Although platinum(II) octaethylporphyrin (PtOEP) doped into 4,4,N,N¢-dicarbazolebiphenyl (CBP) shows an external quantum efficiency g ext = 5.6 %, for a red phosphor, [4,13] the occurrence of T±T annihilation is inevitable at high currents (g ext = 0.5 % at 100 mA cm ±2 ) due to its relatively long phosphorescent lifetime (50±80 ls). Recently, a more efficient red phosphor has been reported, Ir(btp) 2 (acac) [14] (btp = 2-(2¢-benzo[4.5-a]thienyl)pyridinato; acac = acetylacetonate), that achieved an efficiency of g ext = 7.0 % at low current. The relatively short phosphorescent lifetime (4 ls) significantly improves the external efficiency at high currents (g ext = 2.5 % at 100 mA cm ±2 ). A short phosphorescence lifetime is crucial for the performance of a phosphorescent material, particularly its maximum brightness and efficiency at high currents. In this communication, we wish to report a series of efficient red phosphorescent emitters based on iridium 1-(phenyl)isoquinoline complexes which show strong electroluminescence (EL) brightness and efficiency, even at high currents. Scheme 1 outlines the synthetic protocol for red phosphorescent complexes: Ir(piq) 2 (acac), Ir(piq-F) 2 (acac), and Ir(piq-F) 3 , with piq and piq-F representing the 1-(phenyl)isoquinoline and 2-(4¢-fluorophenyl)isoquinoline ligands, respectively. The para-fluoro substituent of Ir(piq-F) 2 (acac) and Ir(piq-F) 3 is used to tune emission wavelength without loss of performance efficiency.[15] 1-(Phenyl)isoquinoline ligand was prepared from the reaction of isoquinoline with the corresponding phenyl magnesium bromide. The complexes Ir-(piq) 2 (acac) and Ir(piq-F) 2 (acac) were ...

Catalytic transformations involving metal carbenes are considered one of the most important aspects of homogeneous transition metal catalysis. Recently, gold-catalyzed generation of gold carbenes from readily available alkynes represents a significant advance in metal carbene chemistry. This Review summarizes the advances in the gold-catalyzed nitrene-transfer reactions of alkynes with nitrogen-transfer reagents, such as azides, nitrogen ylides, isoxazoles, and anthranils, and gold-catalyzed carbene-transfer reactions, involving oxygen atom-transfer reactions of alkynes with nitro compounds, nitrones, sulfoxides, and pyridine N-oxides, through the presumable α-imino gold carbene and α-oxo gold carbene intermediates, respectively. Gold-catalyzed processes are reviewed by highlighting their product diversity, selectivity, and applicability, and the mechanistic rationale is presented where possible.

We report two viable routes for the 1,2-difunctionalization of aminoalkynes using only oxidants. In the presence of a gold catalyst, nitrones enable the oxoamination of aminoalkynes 1 to form 2-aminoamides 2. With a suitable gold catalyst, nitrosobenzenes implement an alkyne/nitroso metathesis of the same substrates to give 2-oxoiminylamides 3. These two novel oxidations also provide 1,2-aminoalcohols with opposite regioselectivity via NaBH(4) reduction in situ.

TpRu(PPh3)(CH3CN)2 PF6 (10 mol %) catalyst effected the nucleophilic addition of water, alcohols, aniline, acetylacetone, pyrroles, and dimethyl malonate to unfunctionalized enediynes under suitable conditions (100 degrees C, 12-24 h) and gave functionalized benzene products in good yields. In this novel cyclization, nucleophiles very regioselectively attack the internal C1' alkyne carbon of enediynes to give benzene derivatives as a single regioisomer. Experiments with methoxy substituents exclude the possible involvement of naphthyl cations as reaction intermediates in the cyclization of (o-ethynylphenyl) alkynes. Deuterium-labeling experiments indicate that the catalytically active species is ruthenium-pi-alkyne rather than ruthenium-vinylidene species. This hypothesis is further confirmed by the aromatization of o-(2'-iodoethynyl)phenyl alkynes with alcohols. We propose a nucleophilic addition/insertion mechanism for this nucleophilic aromatization on the basis of a series of experiments.