- High efficiency electroluminescence of orange-red iridium(III) complexes for OLEDs with an EQE over 30%
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In this study, three pyrazol-pyridine ligands, 2-(3-methyl-1H-pyrazol-5-yl)pyridine (mepzpy), 2-(3-(trifluoromethyl)-1H-pyrazol-5-yl)pyridine (cf3pzpy), and 2-(3-phenyl-1H-pyrazol-5-yl)pyridine (phpzpy) were successfully synthesized for three orange-red iridium (III) complexes Ir1, Ir2, and Ir3, respectively, in which (2,6-bis(trifluoromethyl)pyridin-4-yl)isoquinoline (BTPIQ) was applied as main ligand. Their single crystals were obtained by vacuum sublimation. They showed distinct photoluminescent emissions at 583 nm with a shoulder peak at 624 nm, with high phosphorescence quantum yields of up to 89%. Organic light-emitting devices (OLEDs) with these complexes as emitters exhibits good performances. Especially, the device with Ir3 complex achieves the best performance with a maximum luminance of 24,188 cd m?2, and a highest external quantum efficiency of 30.65%. This research proved that Ir(III) complexes show highly enhanced performance by the modification of electro-donating benzene ring group into ancillary ligands, which also offers us an efficient strategy to obtain high efficiency orange-red Ir(III) complexes for OLEDs.
- Li, Shuaibing,Qu, Junle,Song, Jun,Su, Ning,Yang, Kun,Zhou, Feifan,Zhou, Liang
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- Highly efficient bluish green organic light-emitting diodes of iridium(iii) complexes with low efficiency roll-off
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Two novel iridium(iii) complexes Ir(BTBP)2mepzpy and Ir(BTBP)2phpzpy were successfully synthesized, in which 2′,6′-bis(trifluoromethyl)-2,4′-bipyridine (BTBP) was used as the main ligand, and 2-(3-methyl-1H-pyrazol-5-yl)pyridine (mep
- Su, Ning,Wu, Zheng-Guang,Zheng, You-Xuan
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- Excited-state intramolecular proton transfer in five-membered hydrogen-bonding systems: 2-Pyridyl pyrazoles
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The excited-state intramolecular proton transfer (ESIPT) reaction in five-membered N-H···N hydrogen-bonding systems has been explored through design and syntheses of a series of 5-(2-pyridyl) 1-H-pyrazoles 1a-d. The ESIPT mechanism was confirmed through s
- Yu, Wei-Shan,Cheng, Chung-Chih,Cheng, Yi-Ming,Wu, Pei-Chi,Song, Yi-Hwa,Chi, Yun,Chou, Pi-Tai
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- Interaction of copper(II) with ditopic pyridyl-β-diketone ligands: Dimeric, framework, and metallogel structures
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The interaction of Cu(II) with three β-diketone ligands of type R 1C(O)CH2C(O)R2 (where R1 = 2-, 3-, or 4-pyridyl and R2 = C6H5, respectively), HL1-HL3, alo
- Dudek, Melanie,Clegg, Jack K.,Glasson, Christopher R. K.,Kelly, Norman,Glou, Kerstin,Gloe, Karsten,Kelling, Alexandra,Buschmann, Hans-Juergen,Jolliffe, Katrina A.,Lindoy, Leonard F.,Meehan, George V.
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- Substrate-Controlled Divergent Synthesis of Enaminones and Pyrroles from Indolizines and Nitroso Compounds
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It is imperative to learn new synthetic transformations to succeed in drug discovery and development. We report the substrate-driven synthesis of β-enaminones and N-aryl pyrroles from indolizines and nitrosoarenes; aryl-substituted indolizines lead to β-enaminones in a regio- and diastereoselective manner, whereas alkyl-substituted indolizines produce tetrasubstituted pyrroles. All products contain a pyridine unit, the second most abundant ring (after phenyl) in the FDA Orange Book. In both cases, the reactions proceed at room temperature without any catalyst. Moreover, both types of products can be obtained in one pot from commercial materials as well as at a gram scale. It is worthy of note that the regioselectivity of the β-enaminones is inaccessible by the standard literature methods and their utility has been exemplified in the synthesis of diverse heterocycles. We have made every endeavor to put forward the corresponding reaction mechanisms based on thorough experimental work. (Figure presented.).
- González-Soria, María José,Alonso, Francisco
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supporting information
p. 5005 - 5017
(2019/11/03)
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- Efficient electroluminescence of sky-blue iridium(III) complexes for organic light-emitting diodes
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Two novel sky-blue iridium(III) complexes Ir(dfppy)2pypzpy and Ir(dfppy)2phpzpy were synthesized, in which 2-(2,4-difluorophenyl)pyridine (dfppy) was used as main ligand, 2,2'-(1H-pyrazole-3,5-diyl)dipyridine (pypzpy) and 2-(3-2-(3-p
- Su, Ning,Shen, Cheng-Zhen,Zheng, You-Xuan
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p. 100 - 106
(2018/06/18)
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- Highly efficient green electroluminescence of iridium(iii) complexes based on (1: H -pyrazol-5-yl)pyridine derivatives ancillary ligands with low efficiency roll-off
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Four iridium(iii) complexes, namely Ir-me, Ir-cf3, Ir-py, and Ir-ph, were synthesized, in which 2-(4-trifluoromethyl)phenylpyridine (tfmppy) was used as the main ligand and 2-(3-methyl-1H-pyrazol-5-yl)pyridine (mepzpy), 2-(3-(trifluoromethyl)-1H-pyrazol-5-yl)pyridine (cf3pzpy), 2,2′-(1H-pyrazole-3,5-diyl)dipyridine (pypzpy), and 2-(3-phenyl-1H-pyrazol-5-yl)pyridine (phpzpy) were applied as ancillary ligands, respectively. All complexes showed similar green light peaking at 494-499 nm with high phosphorescence quantum efficiency (0.76-0.82). The organic light-emitting diodes (OLEDs) with the structure of ITO/HATCN (hexaazatriphenylenehexacabonitrile) (5 nm)/TAPC (bis[4-(N,N-ditolylamino)-phenyl]cyclohexane, 50 nm)/Ir complexes (8 wt%): TCTA (4,4′,4′′-tri(9-carbazoyl)triphenylamine, 20 nm)/TmPyPB (1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene, 40 nm)/LiF (1 nm)/Al (100 nm) displayed high current efficiency with low efficiency roll-off. Moreover, the device based on the Ir-me complex exhibited the best performances with a maximum luminance of 38 155 cd m-2, maximum current efficiency of 92 cd A-1, and a maximum external quantum efficiency of 28.90%. These results suggested that green Ir(iii) complexes were obtained by modification of the ppy ligand and rational introduction of (1H-pyrazol-5-yl)pyridine derivatives as the ancillary ligands for high efficient OLEDs.
- Su, Ning,Lu, Guang-Zhao,Zheng, You-Xuan
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p. 5778 - 5784
(2018/06/07)
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- Structure-reactivity relationships in the hydrogenation of carbon dioxide with ruthenium complexes bearing pyridinylazolato ligands
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Pyridinylazolato (N-N') ruthenium(II) complexes of the type [(N-N')RuCl(PMe3)3] have been obtained in high yields by treating the corresponding functionalised azolylpyridines with [RuCl 2(PMe3)4] in the presence of a base. 15N NMR spectroscopy was used to elucidate the electronic influence of the substituents attached to the azolyl ring. The findings are in agreement with slight differences in the bond lengths of the ruthenium complexes. Furthermore, the electronic nature of the azolate moiety modulates the catalytic activity of the ruthenium complexes in the hydrogenation of carbon dioxide under supercritical conditions and in the transfer hydrogenation of acetophenone. DFT calculations were performed to shed light on the mechanism of the hydrogenation of carbon dioxide and to clarify the impact of the electronic nature of the pyridinylazolate ligands. Copyright
- Muller, Keven,Sun, Yu,Heimermann, Andreas,Menges, Fabian,Niedner-Schatteburg, Gereon,Van Wuellen, Christoph,Thiel, Werner R.
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p. 7825 - 7834
(2013/07/05)
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- Gold-catalysed cycloisomerisation reactions of 2-(2-propynyl)pyridine N-oxides leading to indolizinones
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Gold(i)-catalysed tandem oxygen-transfer/cycloisomerisation reaction of 2-(2-propynyl)pyridine N-oxides provides an atom-economical route to indolizinone frameworks.
- Murai, Masahito,Kitabata, Sachie,Okamoto, Kazuhiro,Ohe, Kouichi
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p. 7622 - 7624
(2012/09/22)
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- Preparation, separation and characterisation of two regioisomers of a N-hydroxyalkylpyridylpyrazole ligand: A structural investigation of their coordination to Pd(II), Pt(II) and Zn(II) centres
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The reaction of the β-diketone 1-phenyl-3-(pyridyn-2-yl)propane-1,3- dione, and the monosubstituted hydrazine 2-hydroxyethylhydrazine has been investigated. Two regioisomers were identified, 2-(3-phenyl-5-(pyridyn-2-yl)-1H- pyrazol-1-yl)ethanol (pzol.1) a
- Luque, Carlos,Pons, Josefina,Calvet, Teresa,Font-Bardia, Mer?,García-Antón, Jordi,Ros, Josep
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experimental part
p. 35 - 43
(2011/03/21)
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- Regioselective formation of N-alkyl-3,5-pyrazole derived ligands. A synthetic and computational study
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New N-alkyl-3,5-pyrazole derived ligands were synthesized by reaction between 3,5-pyrazole derived ligands and the appropriate haloalkane in toluene or THF using NaOEt or NaH as base. When the precursor ligand bears a pyridyl substituent the alkylation reaction presents a large regioselectivity. Theoretical calculations have been carried out to rationalize the experimental observations. It has been shown that regioselectivity is governed by the formation of Na+-pyrazolide chelate complexes.
- Montoya, Vanessa,Pons, Josefina,Branchadell, Vicen?,Ros, Josep
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p. 12377 - 12385
(2007/10/03)
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- Syntheses and remarkable photophysical properties of 5-(2-pyridyl) pyrazolate boron complexes; photoinduced electron transfer
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A new series of pyridyl pyrazolate boron complexes 2a-e have been synthesized, in which 2a-c exhibit remarkable dual fluorescence properties due to the photoinduced electron transfer reaction.
- Cheng, Chung-Chih,Yu, Wei-Shan,Chou, Pi-Tai,Peng, Shie-Ming,Lee, Gene-Hsiang,Wu, Pei-Chi,Song, Yi-Hwa,Chi, Yun
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p. 2628 - 2629
(2007/10/03)
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- Molybdenum-catalyzed olefin epoxidation: Ligand effects
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We synthesized substituted pyrazolylpyridine ligands to examine their donor properties by spectroscopic (IR, NMR) and computational (AM 1) methods. The influence of the substitution patterns on spectroscopic and thermodynamic features of molybdenum oxobis
- Thiel, Werner R.,Eppinger, Joerg
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p. 696 - 705
(2007/10/03)
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