- Photophysical and electroluminescence properties of bis(2′,6′-difluoro-2,3′-bipyridinato-N,C4′)iridium(picolinate) complexes: effect of electron-withdrawing and electron-donating group substituents at the 4′ position of the pyridyl moiety of the cyclometalated ligand
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Herein, we have synthesized a series of 2′,6′-difluoro-2,3′-bipyridine cyclometalating ligands by substituting electron-withdrawing (-CHO, -CF3, and -CN) and electron-donating (-OMe and -NMe2) groups at the 4′ position of the pyridyl moiety and utilized them for the construction of five new iridium(iii) complexes (Ir1-Ir5) in the presence of picolinate as an ancillary ligand. The photophysical properties of the developed iridium(iii) compounds were investigated with a view to understand the substituent effects. The strong electron-withdrawing (-CN) group containing the iridium(iii) compound (Ir3) exhibits highly efficient genuine green phosphorescence (λmax = 508 nm) at room temperature in solution and in thin film, with an excellent quantum efficiency (ΦPL) of 0.90 and 0.98, respectively. On the other hand, the -CF3 group substituted iridium(iii) compound (Ir2) displays a sky-blue emission (λmax = 468 nm) with a promising quantum efficiency (ΦPL = 0.88 and 0.84 in solution and in thin film, respectively). The -CHO substituted iridium(iii) complex (Ir1) showed greenish-yellow emission (λmax = 542 nm). Most importantly, the strong electron-donating -NMe2 substituted iridium(iii) complex (Ir5) gives a structureless and a broad emission profile in the wavelength region 450 to 700 nm (λmax = 520 nm) with a poor quantum efficiency. An intense blue phosphorescence with impressive quantum efficiency, especially in thin-film noted in the case of the -OMe substituted iridium(iii) complex (Ir4). Comprehensive density functional theory (DFT) and time-dependent DFT (TD-DFT) approaches have been performed on the ground and excited states of the synthesized iridium(iii) complexes, in order to obtain information about the absorption and emission processes and to gain deeper insights into the photophysical properties. The combinations of a smaller ΔES1-T1 and higher contribution of 3MLCT in the emission process result in the higher quantum yields and lifetime values for complexes Ir1-Ir3. Multi-layered Phosphorescent Organic Light Emitting Diodes (PhOLEDs) were designed using the phosphorescent dopants Ir2, Ir3 and Ir4 and their elecroluminescence properties were evaluated. Compound Ir4 at a doping level of 5 wt% shows the best performance with an external quantum efficiency of 4.7%, in the nonoptimized device, and a power efficiency of 5.8 lm W-1, together with a true-blue chromacity CIEx,y = 0.15, 0.17 recorded at the maximum brightness of 33 180 cd m-2.
- Bejoymohandas,Kumar, Arunandan,Varughese,Varathan,Subramanian,Reddy
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- Rationally Designed Blue Triplet Emitting Gold(III) Complexes Based on a Phenylpyridine-Derived Framework
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A series of blue-emitting phosphorescent mono-cyclometalated AuIII complexes have been successfully synthesized. Tailoring the substitutions on the phenylpyridine (ppy) ligand scaffold with electron-withdrawing fluorine groups on the phenyl ring to achieve stabilization of the HOMO and an electron-donating dimethylamino group on the pyridine ring to destabilize the LUMO resulted in a large energy gap and bestowed on the gold(III) complexes high-energy emission and high quantum efficiencies. The results of cyclic voltammetry studies suggested a predominantly redox event localized on the cyclometalated ligand. Thermogravimetric analysis of selected complexes revealed a high stability up to 280 °C, thus the complexes are suitable for device fabrication through vacuum-deposition. Photophysical investigations performed on all the derivatives revealed phosphorescence emission in neat solid, solution, doped in poly(methyl methacrylate) (PMMA) films at room temperature as well as in rigidified glass media (2-MeTHF) at 77 K. A high photoluminescent quantum efficiency of 28 % was obtained for a complex in PMMA, the highest quantum yield reported for a blue-emitting gold(III) complex.
- Bachmann, Michael,Terreni, Jasmin,Blacque, Olivier,Venkatesan, Koushik
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- First direct C-2-lithiation of 4-DMAP. Convenient access to reactive functional derivatives and ligands
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The first direct α-lithiation of 4-DMAP has been peformed via reaction with the BuLi-Me2N(CH2)2-OLi (BuLi-LiDMAE) reagent. This new methodology avoids the use of a activation-lithiation-regeneration sequence or halogen-met
- Cuperly, David,Gros, Philippe,Fort, Yves
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- High Triplet Energy Iridium(III) Isocyanoborato Complex for Photochemical Upconversion, Photoredox and Energy Transfer Catalysis
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Cyclometalated Ir(III) complexes are often chosen as catalysts for challenging photoredox and triplet–triplet-energy-transfer (TTET) catalyzed reactions, and they are of interest for upconversion into the ultraviolet spectral range. However, the triplet e
- Glaser, Felix,Schaer, Raoul,Schmid, Lucius,Wenger, Oliver S.
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supporting information
p. 963 - 976
(2022/01/19)
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- Structure-Activity Relationships of Radioiodinated 6,5,6-Tricyclic Compounds for the Development of Tau Imaging Probes
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Tau aggregate, which is the main component of the neurofibrillary tangle, is an attractive imaging target for diagnosing and monitoring the progression of Alzheimer's disease (AD). In this study, we designed and synthesized six radioiodinated 6,5,6-tricyc
- Watanabe, Hiroyuki,Tatsumi, Haruka,Kaide, Sho,Shimizu, Yoichi,Iikuni, Shimpei,Ono, Masahiro
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supporting information
p. 120 - 126
(2020/02/06)
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- BENZOSULFONYL COMPOUNDS
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Provided herein are compounds and pharmaceutical compositions comprising said compounds that are useful for treating cancers. Specific cancers include those that are mediated by YAP/TAZ or those that are modulated by the interaction between YAP/TAZ and TEAD.
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Paragraph 00367
(2019/03/12)
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- Modifying Emission Spectral Bandwidth of Phosphorescent Platinum(II) Complexes Through Synthetic Control
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The design, synthesis, and characterization of a series of tetradentate cyclometalated Pt(II) complexes are reported. The platinum complexes have the general structure Pt(ppz-O-CbPy-R), where a tetradentate cyclometalating ligand is consisting of ppz (3,5
- Li, Guijie,Wolfe, Alicia,Brooks, Jason,Zhu, Zhi-Qiang,Li, Jian
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supporting information
p. 8244 - 8256
(2017/07/22)
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- Nucleophilic Aromatic Substitution Reactions in Water Enabled by Micellar Catalysis
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Given the huge dependence on dipolar, aprotic solvents such as DMF, DMSO, DMAc, and NMP in nucleophilic aromatic substitution reactions (SNAr), a simple and environmentally friendly alternative is reported. Use of a "benign-by-design" nonionic surfactant, TPGS-750-M, in water enables nitrogen, oxygen, and sulfur nucleophiles to participate in SNAr reactions. Aromatic and heteroaromatic substrates readily participate in this micellar catalysis, which takes place at or near ambient temperatures.
- Isley, Nicholas A.,Linstadt, Roscoe T. H.,Kelly, Sean M.,Gallou, Fabrice,Lipshutz, Bruce H.
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supporting information
p. 4734 - 4737
(2015/10/12)
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- A novel neutral organic electron donor with record half-wave potential
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Tricyclic donor 26 has been prepared and is the most reducing neutral ground-state organic molecule known, with an oxidation potential 260 mV more negative than the previous record. Cyclic voltammetry shows that a 2-electron reversible redox process occurs in DMF as solvent at -1.46 V vs. Ag/AgCl.
- Farwaha, Hardeep S.,Bucher, Goetz,Murphy, John A.
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p. 8073 - 8081
(2013/12/04)
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- Phosphorescent light-emitting iridium complex containing pyridyltriazole ligand
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An Ir complex having a pyridyl triazole ligand substituted with at least one substituent on its pyridyl ring, and a light emitting material comprising such Ir complex. Such light emitting material was found to have a significantly enhanced photophosphorescence quantum yield and hypsochromic blue shifted photophosphorescent emission over other Ir complexes with a pyridyl triazole ligand having no substituent in its pyridine ring. Use of such light emitting material and an organic light emitting device including the same.
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- DERIVATIVES OF 2-PYRIDIN-2-YL-PYRAZOL-3(2H)-ONE, PREPARATION AND THERAPEUTIC USE THEREOF
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The invention relates to compounds corresponding to formula (I), in the form of the base or of an acid-addition salt: in which n is equal to 0, 1, 2, 3 or 4; m is equal to 0, 1 or 2; o is equal to 0 or 1; X represents a group —CH2, —CH(R′)—, —N
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Page/Page column 7
(2011/12/14)
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- A simple synthesis of functionalized 3-methyl-1-pyridinyl-1H-imidazolium salts as bidentate N-heterocyclic-carbene precursors and their application in Ir-catalyzed arene borylation
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The selective alkylation of functionalized 2-(1H-imidazol-1-yl)pyridines 1 furnishes 3-methyl-1-pyridinyl-1H-imidazolium salts 2, which can be deprotonated to deliver strongly electron-donating bidentate N-heterocyclic carbene ligands (NHC). The synthesis of these ligands and their application in the iridiumcatalyzed C-H activated borylation of arenes with its current scope and limitations are reported.
- Peters, Martin,Breinbauer, Rolf
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supporting information; experimental part
p. 6622 - 6625
(2011/02/21)
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- SPIROPIPERIDINE DERIVATIVES
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The invention provides compounds of formula (I): wherein the dotted line represents an optional covalent bond between X and Y, and X, Y, Z, m, R2, R3, R4, R5, R6, R7, R8, R9, a and b have the meanings given in the specification, and pharmaceutically acceptable salts and solvates thereof. The compounds are delta opioid receptor agonists and have a number of therapeutic applications, particularly in the treatment of pain.
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Page/Page column 159-160
(2010/11/27)
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