- Photoluminescence and electroluminescence of four platinum complexes with trifluoromethyl-substituted 2-phenylpyridine and tetraphenylimidodiphosphinate ligands
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Four cyclometalated platinum complexes with trifluoromethyl-substituted 2-phenylpyridine at different positions on its phenyl group as the main ligands and tetraphenylimidodiphosphinate as the ancillary ligand, Pt1-Pt4 (Pt1 is a trifluoromethyl-free compl
- Lu, Guang-Zhao,Han, Hua-Bo,Li, Yan,Zheng, You-Xuan
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- Highly Luminescent Mono- and Dinuclear Cationic Iridium(III) Complexes Containing Phenanthroline-Based Ancillary Ligand
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A new family of mononuclear (1–2) and dinuclear (3–5) cationic iridium(III) complexes have been synthesized and fully characterized. These complexes contain 2-(4-(trifluoromethyl)phenyl)pyridine (cf3ppy, L1) and 1-(4-(trifluoromethyl)phenyl)iso
- Yang, Xiao-Han,Li, Min,Peng, Hui,Zhang, Qian,Wu, Shui-Xing,Xiao, Wan-Qing,Chen, Xing-Liang,Niu, Zhi-Gang,Chen, Guang-Ying,Li, Gao-Nan
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- Organocatalytic synthesis of (Het)biaryl scaffoldsviaphotoinduced intra/intermolecular C(sp2)-H arylation by 2-pyridone derivatives
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A uniqueN,O-bidentate ligand 6-oxo-1,6-dihydro-pyridone-2-carboxylic acid dimethylamide (L1) catalyzed direct C(sp2)-H (intra/intermolecular) arylation of unactivated arenes has been developed to expedite access to (Het)biaryl scaffolds under UV-irradiation at room temperature. The protocol tolerated diverse functional groups and substitution patterns, affording the target products in moderate to excellent yields. Mechanistic investigations were also carried out to better understand the reaction pathway. Furthermore, the synthetic applicability of this unified approach has been showcasedviathe construction of biologically relevant 4-quinolone, tricyclic lactam and sultam derivatives.
- Das, Tapas Kumar,Kundu, Mrinalkanti,Mondal, Biswajit,Ghosh, Prasanjit,Das, Sajal
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p. 208 - 218
(2021/12/29)
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- Nickel-Catalyzed Reductive 2-Pyridination of Aryl Iodides with Difluoromethyl 2-Pyridyl Sulfone
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A novel nickel-catalyzed reductive cross-coupling between aryl iodides and difluoromethyl 2-pyridyl sulfone (2-PySO2CF2H) enables C(sp2)-C(sp2) bond formation through selective C(sp2)-S bond cleavage, which demonstrates the new reactivity of 2-PySO2CF2H reagent. This method employs readily available nickel catalyst and sulfones as cross-electrophile coupling partners, providing facile access to biaryls under mild reaction conditions without pregeneration of arylmetal reagents.
- Miao, Wenjun,Ni, Chuanfa,Xiao, Pan,Jia, Rulong,Zhang, Wei,Hu, Jinbo
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supporting information
p. 711 - 715
(2021/01/26)
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- Highly efficient phosphorescent organic light-emitting diodes based on novel bipolar iridium complexes with easily-tuned emission colors by adjusting fluorine substitution on phenylpyridine ligands
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Two new phenylpyridine derivative-based heteroleptic iridium complexes, (Fppy)2Ir(dipg) (Fppdg) and (CF3ppy)2Ir(dipg) (tFmppdg) with emission peaks of 545 nm and 581 nm, respectively, were designed and synthesized by incorporation of a dipg group (N,N′-diisopro-guanidinate) as the ancillary ligand. Their photophysical, thermal, electrochemical and electroluminescence properties were investigated. The results indicate that the emitting color of phosphorescent complexes can be tuned easily by adjusting their F/CF3-substituted cyclometalated ligands. Simultaneously, Fppdg and tFmppdg show good thermal stabilities, short lifetimes of the triplet state and high photoluminescence quantum yields. More importantly, their almost complete spatial separation of HOMO and LUMO distributions endows both phosphors with an amazing bipolar charge transporting ability, and thus the corresponding doped OLEDs possess desirable concentration-independent and negligible efficiency roll-off features: at a rather wide concentration range of 8-25% doped in the CBP host, both phosphors realize a very high peak external quantum efficiency (EQE) level of >20%, and maintain values of >18% at a practical luminance of 1000 cd m?2
- Chen, Shuonan,Gai, Xi,Liang, Jie,Liu, Yu,Wang, Yue,Ye, Kaiqi
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p. 8329 - 8336
(2021/07/13)
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- Borenium-Catalyzed Reduction of Pyridines through the Combined Action of Hydrogen and Hydrosilane
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Mesoionic carbene-stabilized borenium ions efficiently reduce substituted pyridines to piperidines in the presence of a hydrosilane and a hydrogen atmosphere. Control experiments and deuterium labeling studies demonstrate reversible hydrosilylation of the pyridine, enabling full reduction of the N-heterocycle under milder conditions. The silane is a critical reaction component to prevent adduct formation between the piperidine product and the borenium catalyst.
- Clarke, Joshua J.,Maekawa, Yuuki,Nambo, Masakazu,Crudden, Cathleen M.
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supporting information
p. 6617 - 6621
(2021/09/02)
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- Reversible On-Off Switching of Excitation-Wavelength-Dependent Emission of a Phosphorescent Soft Salt Based on Platinum(II) Complexes
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Excitation-wavelength-dependent (Ex-De) emission materials show excellent potential in diverse advanced photonic areas. Of significant importance is the on-demand regulation of the Ex-De luminescence behavior of these materials, which is previously unprecedented. In this study, we report on a platinum(II) complex-based phosphorescent soft salt S1 ([Pt(tpp)(ed)]+[Pt(ftpp)(CN)2]- (where ttp = 2-(4-(trifluoromethyl)phenyl)pyridine, ed = ethane-1,2-diamine, and ftpp = 2-(4-fluoro-3-(trifluoromethyl)phenyl)pyridine)) with Ex-De photoluminescence (PL) property. UV-visible absorption and PL spectra of S1 were recorded in DMSO-H2O mixture (1 × 10-3 M) with various H2O fractions to investigate its ground and excited states. Interestingly, the PL spectra of S1 powder show that its maximum emission peak is red-shifted from 595 to 644 nm upon excitation at different wavelengths from 360 to 520 nm, accompanied by an obvious emission color change from yellow-orange to red. Furthermore, confocal laser scanning fluorescence microscopy was employed to determine the PL property of self-assembled uniform S1 nanostructure, and the result shows that the Ex-De emission behavior is absent. On the basis of these results, we conclude the various Pt(II)···Pt(II) distances that exist are the major factor responsible for the properties of the Ex-De PL of S1 powder. Thus, for the first time, reversible on-off switching of Ex-De PL of S1 was achieved by manipulating its Pt(II)···Pt(II) distances through mechanical stress and vapor fuming. Finally, we demonstrate the high-level anticounterfeiting applications via on-demand multicolor displays.
- Li, Jiangang,Chen, Kexin,Wei, Juan,Ma, Yun,Zhou, Ruyi,Liu, Shujuan,Zhao, Qiang,Wong, Wai-Yeung
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supporting information
p. 18317 - 18324
(2021/11/16)
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- Direct suzuki-miyaura coupling with naphthalene-1,8-diaminato (dan)-substituted organoborons
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The actually direct Suzuki-Miyaura coupling with "protected" R-B(dan) (dan = naphthalene-1,8-diaminato) was demonstrated to smoothly occur without in situ deprotection of the B(dan) moiety. The use of t-BuOK (Ba(OH)2 in some cases) as a base under anhydrous conditions is the key to the successful cross-coupling, where R-B(dan) is readily converted into a transmetalation-active borate-form, regardless of the well-accepted diminished boron-Lewis acidity.
- Yoshida, Hiroto,Seki, Michinari,Kamio, Shintaro,Tanaka, Hideya,Izumi, Yuki,Li, Jialun,Osaka, Itaru,Abe, Manabu,Andoh, Hiroki,Yajima, Tomoki,Tani, Tomohiro,Tsuchimoto, Teruhisa
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p. 346 - 351
(2019/12/24)
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- Study of the Synthesis and Properties of Ir(III) Complexes Based on Phosphine Carbonylimide Derivative as Auxiliary Ligand
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Three iridium complexes of (dfppy)2Ir(DAPB), (dfppy)2Ir(DAPB), and (dfppy)2Ir(DAPB) were synthesized by using phosphine carbonylimide derivative as auxiliary ligand and fluoro?/trifluoromethyl substituted 2-phenylpyridine
- Guo, Qing-Mei,Huang, Guo-Li,Yin, Xin-Ying,Bian, Jian-Jian,Li, Xiao-Mei,Teng, Ming-Yu
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p. 1184 - 1189
(2020/11/03)
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- Meta-dehydrogenative alkylation of arenes with ethers, ketones, and esters catalyzed by ruthenium
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A meta-dehydrogenative alkylation of arenes with cyclic ethers, ketones, and esters catalyzed by ruthenium is achieved in the presence of a di-tert-butyl peroxide (DTBP) oxidant. Interestingly, when quinoline and isoquinoline are employed as the directing group, or a chain ether as alkylation reagent, the system produces Minisci reaction products. Mechanistic study indicates that meta-dehydrogenative alkylation is a radical process initiated by DTBP with the assistance of a CAr-Ru bond ortho/para-directing effect.
- Li, Gang,Gao, Yuan,Jia, Chunqi,Wang, Shichong,Yan, Bingxu,Fang, Yu,Yang, Suling
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supporting information
p. 8758 - 8763
(2020/12/02)
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- Orthogonal Nanoparticle Catalysis with Organogermanes
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Although nanoparticles are widely used as catalysts, little is known about their potential ability to trigger privileged transformations as compared to homogeneous molecular or bulk heterogeneous catalysts. We herein demonstrate (and rationalize) that nanoparticles display orthogonal reactivity to molecular catalysts in the cross-coupling of aryl halides with aryl germanes. While the aryl germanes are unreactive in LnPd0/LnPdII catalysis and allow selective functionalization of established coupling partners in their presence, they display superior reactivity under Pd nanoparticle conditions, outcompeting established coupling partners (such as ArBPin and ArBMIDA) and allowing air-tolerant, base-free, and orthogonal access to valuable and challenging biaryl motifs. As opposed to the notoriously unstable polyfluoroaryl- and 2-pyridylboronic acids, the corresponding germanes are highly stable and readily coupled. Our mechanistic and computational studies provide unambiguous support of nanoparticle catalysis and suggest that owing to the electron richness of aryl germanes, they preferentially react by electrophilic aromatic substitution, and in turn are preferentially activated by the more electrophilic nanoparticles.
- Fricke, Christoph,Sherborne, Grant J.,Funes-Ardoiz, Ignacio,Senol, Erdem,Guven, Sinem,Schoenebeck, Franziska
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supporting information
p. 17788 - 17795
(2019/11/13)
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- Metal-Free Aerobic Oxidative Selective C-C Bond Cleavage in Heteroaryl-Containing Primary and Secondary Alcohols
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A transition-metal-free aerobic oxidative selective C-C bond-cleavage reaction in primary and secondary heteroaryl alcohols is reported. This reaction was highly efficient and tolerated various heteroaryl alcohols, generating a carboxylic acid derivative and a neutral heteroaromatic compound. Experimental studies combined with density functional theory calculations revealed the mechanism underlying the selective C-C bond cleavage. This strategy also provides an alternative simple approach to carboxylation reaction.
- Xia, Anjie,Qi, Xueyu,Mao, Xin,Wu, Xiaoai,Yang, Xin,Zhang, Rong,Xiang, Zhiyu,Lian, Zhong,Chen, Yingchun,Yang, Shengyong
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- Decarboxylative Arylation of Pyridine 1-Oxides and Anilides with Benzoic Acid via Palladium-Catalyzed C–H Functionalization
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A novel method for the palladium-catalyzed decarboxylative ortho C–H bond arylation of pyridine 1-oxides and anilides with benzoic acids as aryl sources is described. The established methodology provides a direct approach for the synthesis of 2-arylpyridine 1-oxides and 2-aryl anilides in good isolated yields.
- Dabiri, Minoo,Alavioon, Seyed Iman,Movahed, Siyavash Kazemi
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p. 1479 - 1487
(2019/02/19)
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- Multicomponent Aromatic and Benzylic Mannich Reactions through C?H Bond Activation
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Multicomponent Mannich reactions through C?H bond activation are described. These transformations allowed for the straightforward generation of densely substituted benzylic and homo-benzylic amines in good yields. The reaction involves a reaction between two transient species: an organometallic species, generated by transition-metal-catalyzed sp2 or sp3 C?H bond activation and an in situ generated imine. The use of an acetal as an aldehyde surrogate was found essential for the reaction to proceed. The process could be successfully applied to RhIII-catalyzed sp2 C?H bond functionalization and extended to CuII-catalyzed sp3 C?H bond functionalization.
- Xavier, Tania,Rayapin, Corinne,Le Gall, Erwan,Presset, Marc
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supporting information
p. 13824 - 13828
(2019/11/03)
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- N-heterocyclic carbene enabled rhodium-catalyzed ortho C(sp2)-H borylation at room temperature
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We report a rhodium-catalyzed ortho C(sp2)-H borylation of 2-phenylpyridines using commercially available N-heterocyclic carbenes (NHCs) as ligand and pinacolatodiboron (B2pin2) as borylating reagent. The reaction could take place at room temperature, tolerating a wide range of functionalities and affording ortho borylated products in moderate to excellent yields. The current method is also applicable to gram-scale reaction with reduced catalyst loading.
- Zhong, Lei,Zong, Zhi-Hong,Wang, Xi-Cun
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supporting information
p. 2547 - 2552
(2019/03/27)
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- Enabling Catalytic Arene C-H Amidomethylation via Bis(tosylamido)methane as a Sustainable Formaldimine Releaser
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Addition of catalytic arene C-H to formaldimines has been enabled by Ru(II)-catalyzed amidomethylation with bis(tosylamido)methane as a catalytic formaldimine releaser. The new process provides an atom-efficient and sustainable solution to address the challenges of formaldimines in this type of transformation. Furthermore, new synthetic routes based on this catalytic system have been developed for step-efficient access to N-heterotricyclic core structures that are pharmaceutically relevant.
- Li, Zhong-Yuan,Chaminda Lakmal, Hetti Handi,Cui, Xin
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supporting information
p. 3735 - 3740
(2019/05/24)
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- Green-emitting iridium(iii) complexes containing pyridine sulfonic acid as ancillary ligands for efficient OLEDs with extremely low efficiency roll-off
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A novel ancillary ligand of pyridine sulfonic acid (PySO3) was developed for two green-emitting iridium(iii) compounds, Ir1 (λmax = 496 nm) and Ir2 (λmax = 504 nm), with trifluoromethyl-substituted 2-phenylpyridine derivatives as the main ligands. Due to the strong electron-withdrawing ability of PySO3, both complexes have relatively low LUMO energy levels and good electron mobility, which benefit the charge balance in the organic light-emitting diodes (OLEDs) during the electroluminescence process. Therefore, all devices with double light-emitting layers exhibit good performances. In particular, the device using Ir2 as an emitter obtains a maximum luminance above 92000 cd m-2, a maximum external quantum efficiency (EQEmax) of 25.5% with an extremely low efficiency roll-off, and the EQE still remains at 22.9% at the high luminance of 20000 cd m-2. These results demonstrate that pyridine sulfonic acid is a potential and charming ligand for Ir(iii) complexes and high-performance OLEDs.
- Zhang, Lin,Yan, Zhi-Ping,Tu, Zhen-Long,Wu, Zheng-Guang,Zheng, You-Xuan
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p. 11606 - 11611
(2019/10/02)
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- Reversible Concerted Metalation-Deprotonation C-H Bond Activation by [Cp*RhCl2]2
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The reversibility of the concerted metalation-deprotonation exchange of eight para-substituted phenylpyridines is examined with the parent Cp*RhCl(κ-C,N-NC5H4-C6H4). Equilibrium constants are determined, and the free energies are used to extract the most important parameters that control the thermodynamics. Keq values are found to correlate best with heterolytic C-H bond strengths but in a way that is not obvious considering the electrophilic nature of these activations.
- Vanderweide, Andrew I.,Brennessel, William W.,Jones, William D.
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supporting information
p. 12960 - 12965
(2019/10/11)
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- NITROGEN-CONTAINING BIOPOLYMER-BASED CATALYSTS, THEIR PREPARATION AND USES IN HYDROGENATION PROCESSES, REDUCTIVE DEHALOGENATION AND OXIDATION
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The present invention relates to a process for the preparation of a nitrogen containing biopolymer-based catalyst by pyrolysis of a metal complex with a nitrogen-containing biopolymer and to the nitrogen containing biopolymer-based catalysts obtainable by this process. In particular, the invention relates to a nitrogen containing biopolymer-based catalyst comprising metal particles and at least one nitrogen containing carbon layer. The invention also relates to the use of a nitrogen containing biopolymer-based catalyst in a hydrogenation process, preferably in a process for hydrogenation of nitroarenes, nitriles or imines; in a reductive dehalogenation process of C-X bonds, wherein X is CI, Br or I, preferably in a process for dehalogenation of organohalides or in a process for deuterium labelling of arenes via dehalogenation of organohalides; or in an oxidation process. Further, the invention relates to a metal complex with the nitrogen containing biopolymer, wherein the metal is a transition metal selected from the group consisting of manganese, ruthenium, cobalt, rhodium, nickel, palladium and platinum, preferably cobalt or nickel, and wherein the nitrogen containing biopolymer is selected from chitosan, chitin and a polyamino acid, preferably chitosan or chitin.
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Page/Page column 20-21
(2018/07/29)
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- Suzuki-Miyaura cross-coupling for efficient synthesis of aryl-substituted N-heteroarenes catalyzed by recyclable N-phenylpiperazine-Palladium(II) complex
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Polystyrene supported N-phenylpiperazine-Pd(II) complex D was synthesized and characterized by various techniques, including Fourier transform infrared spectroscopy (FTIR), scanning electronmicroscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and thermal analysis (TG-DTA). This heterogeneous Pd(II) complex showed high catalytic efficiency for the Suzuki-Miyaura coupling of arylboronic acids with aryl bromides, aryl chlorides to give the corresponding 2-arylpyridines and heteroarenes. The coupled products were formed in excellent yields at low catalyst loadings under mild reaction conditions. Further, this heterogeneous catalyst showed excellent recyclability and reused for four cycles with no significant decrease in its activity.
- Perumgani, Pullaiah C.,Kodicherla, Balaswamy,Mandapati, Mohan Rao,Parvathaneni, Sai Prathima
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p. 227 - 232
(2018/04/02)
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- [2,2′-bipyridin]-6(1 H)-one, a Truly Cooperating Ligand in the Palladium-Mediated C-H Activation Step: Experimental Evidence in the Direct C-3 Arylation of Pyridine
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The ligand [2,2′-bipyridin]-6(1H)-one (bipy-6-OH) has a strong accelerating effect on the Pd-catalyzed direct arylation of pyridine or arenes. The isolation of relevant intermediates and the study of their decomposition unequivocally show that the deprotonated coordinated ligand acts as a base and assists the cleavage of the C-H bond. Mechanistic work indicates that the direct arylation of pyridine with this ligand occurs through a Pd(0)/Pd(II) cycle. Because of this dual ligand-intramolecular base role, there is no need for an available coordination site on the metal for an external base, a difficulty encountered when chelating ligands are used in coupling reactions that involve a C-H cleavage step.
- Salamanca, Vanesa,Toledo, Alberto,Albéniz, Ana C.
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supporting information
p. 17851 - 17856
(2019/01/04)
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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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- Directed: Ortho C-H borylation catalyzed using Cp?Rh(iii)-NHC complexes
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Cp?Rh(NHC) complexes with bulky chiral bidentate NHC-carboxylate ligands were efficiently synthesized and fully characterized including solid-state structures. These unprecedented rhodium(iii) complexes demonstrated high selectivity in pyridine-directed ortho-C-H borylation of arenes under mild conditions.
- Thongpaen, Jompol,Schmid, Thibault E.,Toupet, Loic,Dorcet, Vincent,Mauduit, Marc,Baslé, Olivier
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supporting information
p. 8202 - 8205
(2018/07/29)
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- Iridium(iii) phosphors with bis(diphenylphorothioyl)amide ligand for efficient green and sky-blue OLEDs with EQE of nearly 28%
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In this study, a new ligand, bis(diphenylphorothioyl)amide (Stpip), containing phosphorus-sulfur (PS) bonds was synthesized as an ancillary ligand. Four iridium(iii) complexes (Ir(ppy)2(Stpip), Ir(tfppy)2(Stpip), Ir(ttppy)2/sub
- Xia, Jing-Cheng,Liang, Xiao,Yan, Zhi-Ping,Wu, Zheng-Guang,Zhao, Yue,Zheng, You-Xuan,Zhang, Wen-Wei
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p. 9010 - 9016
(2018/09/09)
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- Cobalt-Catalyzed Cross-Coupling Reactions of Arylboronic Esters and Aryl Halides
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An efficient cobalt catalyst system for the Suzuki-Miyaura cross-coupling reaction of arylboronic esters and aryl halides has been identified. In the presence of cobalt(II)/terpyridine catalyst and potassium methoxide, a diverse array of (hetero)biaryls have been prepared in moderate to excellent yields.
- Duong, Hung A.,Wu, Wenqin,Teo, Yu-Yuan
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supporting information
p. 4363 - 4366
(2017/12/05)
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- Pyridine sulfinates as general nucleophilic coupling partners in palladium-catalyzed cross-coupling reactions with aryl halides
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Pyridine rings are ubiquitous in drug molecules; however, the pre-eminent reaction used to form carbon-carbon bonds in the pharmaceutical industry, the Suzuki-Miyaura cross-coupling reaction, often fails when applied to these structures. This phenomenon is most pronounced in 2-substituted pyridines, and results from the difficulty in preparing, the poor stability of, and low efficiency in reactions of pyridine-2-boronates. We demonstrate that by replacing these boronates with pyridine-2-sulfinates, a cross-coupling process of unrivalled scope and utility is realized. The corresponding 3-And 4-substituted pyridine variants are also efficient coupling partners. In addition, we apply these sulfinates in a library format to the preparation of medicinally relevant derivatives of the drugs varenicline (Chantix) and mepyramine (Anthisan).
- Markovic, Tim,Rocke, Benjamin N.,Blakemore, David C.,Mascitti, Vincent,Willis, Michael C.
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p. 4437 - 4442
(2017/07/11)
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- A Biomass-Derived Non-Noble Cobalt Catalyst for Selective Hydrodehalogenation of Alkyl and (Hetero)Aryl Halides
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Hydrodehalogenation is a straightforward approach for detoxifications of harmful anthropogenic organohalide-based pollutants, as well as removal of halide protecting groups used in multistep syntheses. A novel sustainable catalytic material was prepared from biowaste (chitosan) in combination with an earth-abundant cobalt salt. The heterogeneous catalyst was fully characterized by transmission electron microscope, X-ray diffraction, and X-ray photoelectron spectroscopy measurements, and successfully applied to hydrodehalogenation of alkyl and (hetero)aryl halides with broad scope (>40 examples) and excellent chemoselectivity using molecular hydrogen as a reductant. The general usefulness of this method is demonstrated by successful detoxification of non-degradable pesticides and fire retardants. Moreover, the potential of the catalyst as a deprotection tool is demonstrated in a multistep synthesis of (±)-peronatin B (alkaloid).
- Sahoo, Basudev,Surkus, Annette-Enrica,Pohl, Marga-Martina,Radnik, J?rg,Schneider, Matthias,Bachmann, Stephan,Scalone, Michelangelo,Junge, Kathrin,Beller, Matthias
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supporting information
p. 11242 - 11247
(2017/09/02)
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- Blue light mediated C-H arylation of heteroarenes using TiO2 as an immobilized photocatalyst in a continuous-flow microreactor
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Titanium dioxide was applied as an immobilized photocatalyst in a microstructured falling film reactor for the continuous-flow C-H arylation of heteroarenes with aryldiazonium salts as the starting material. Detailed investigations of the catalyst and a successful long-term run proved its excellent usability for this process. Very good yields up to 99% were achieved with broad substrate scope and were compared with batch synthesis. The transfer to the continuous-flow mode revealed an impressive boost in reactor performance solely resulting from the improved irradiation and contact of the catalyst, substrate and light.
- Fabry, David C.,Ho, Yee Ann,Zapf, Ralf,Tremel, Wolfgang,Panth?fer, Martin,Rueping, Magnus,Rehm, Thomas H.
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supporting information
p. 1911 - 1918
(2017/06/09)
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- Direct C-H Functionalization of Pyridine via a Transient Activator Strategy: Synthesis of 2,6-Diarylpyridines
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A Pd-catalyzed highly selective direct diarylation of pyridines has been developed using a transient activator strategy. Both (MeO)2SO2 and Cu2O are required for this transformation. The in situ generated N-methylpyridinium salt can be arylated at both 2- and 6-positions under the cooperative Pd/Cu catalysis. A subsequent N-demethylation then gives the 2,6-diarylpyridines. This protocol provides a novel synthetic route for the symmetric 2,6-diarylpyridines.
- Zeng, Yang,Zhang, Chunchun,Yin, Changzhen,Sun, Maoshen,Fu, Haiyan,Zheng, Xueli,Yuan, Maolin,Li, Ruixiang,Chen, Hua
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supporting information
p. 1970 - 1973
(2017/04/27)
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- Efficient Electroluminescence of Two Heteroleptic Platinum Complexes with a 2-(5-Phenyl-1,3,4-oxadiazol-2-yl)phenol Ancillary Ligand
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Two new platinum(II) cyclometalated complexes with 2-phenylpyridine (Pt1) and 2-(4-trifluoromethyl)phenylpyridine (Pt2) as the main ligands and 2-(5-phenyl-1,3,4-oxadiazol-2-yl)phenol (pop) as the electron-transporting ancillary ligand were developed. The photoluminescence quantum efficiency yields of both green Pt1 and Pt2 phosphors (λmax 490 and 496 nm) are 20.0% and 31.0% in CH2Cl2 solutions, respectively. Efficient OLEDs (organic light emitting diodes) of ITO/TAPC (bis[4-(N,N-ditolylamino)phenyl]cyclohexane, 40 nm)/Pt1 or Pt2 (5 wt %):TCTA (4,4′,4″-tri(carbazoyl-9-yl)triphenylamine, 10 nm)/Pt1 or Pt2 (5 wt %):2,6DCzPPy (2,6-bis(3-(carbazol-9-yl)phenyl)pyridine, 10 nm)/TmPyPB (1,3,5-tris(m-pyrid-3-ylphenyl)benzene, 40 nm)/LiF (1 nm)/Al (100 nm) were fabricated. Particularly, device G1 based on complex Pt1 with 5 wt % doped concentration showed superior performance with a maximum current efficiency (ηmax,c) of 55.6 cd A-1, a maximum power efficiency (ηmax,p) of 52.2 lm W-1, and a maximum external quantum efficiency (EQEmax) of 18.0%. Device G2 with the Pt2 emitter displayed lower efficiency rolloff with ηc values of 48.5 and 43.1 cd A-1 as the luminance reached 5000 and 10000 cd m-2, respectively. These research results demonstrate that the Pt(II) complexes with an ancillary ligand attached with the 1,3,4-oxadiazole group have promising applications in efficient OLEDs.
- Lu, Guang-Zhao,Jing, Yi-Ming,Han, Hua-Bo,Fang, Yu-Liang,Zheng, You-Xuan
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supporting information
p. 448 - 454
(2017/04/26)
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- α-Halo carbonyls enable: Meta selective primary, secondary and tertiary C-H alkylations by ruthenium catalysis
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A catalytic meta selective C-H alkylation of arenes is described using a wide range of α-halo carbonyls as coupling partners. Previously unreported primary alkylations with high meta selectivity have been enabled by this methodology whereas using straight chain alkyl halides affords ortho substituted products. Mechanistic analysis reveals an activation pathway whereby cyclometalation with a ruthenium(ii) complex activates the substrate molecule and is responsible for the meta selectivity observed. A distinct second activation of the coupling partner allows site selective reaction between both components.
- Paterson, Andrew J.,Heron, Callum J.,McMullin, Claire L.,Mahon, Mary F.,Press, Neil J.,Frost, Christopher G.
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supporting information
p. 5993 - 6000
(2017/07/25)
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- Palladium-catalyzed C-H alkylation of 2-phenylpyridines with alkyl iodides
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Palladium-catalyzed C-H alkylation reaction of 2-phenylpyridines with alkyl iodides has been successfully developed. The palladacycles obtained from 2-phenylpyridines should act as the key intermediates in the alkylation reaction.
- Wang, Xiaoling,Ji, Xiaoming,Shao, Changdong,Zhang, Yu,Zhang, Yanghui
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supporting information
p. 5616 - 5624
(2017/07/12)
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- Syntheses, photoluminescence and electroluminescence of two novel platinum(ii) complexes
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Two new platinum(ii) cyclometalated complexes with 2-(4-trifluoromethyl)phenylpyridine (4-tfmppy) as the main ligand and tetraphenylimidodiphosphinate (tpip) (Pt-tpip) and tetra(4-fluorophenyl)imidodiphosphinate (ftpip) (Pt-ftpip) as ancillary ligands wer
- Lu, Guang-Zhao,Li, Yan,Jing, Yi-Ming,Zheng, You-Xuan
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p. 150 - 157
(2016/12/28)
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- Ru-Catalyzed Regioselective Direct Hydroxymethylation of (Hetero)Arenes via C-H Activation
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An efficient and direct ruthenium-catalyzed regioselective hydroxymethylation of (hetero)arenes via C-H activation with paraformaldehyde as a hydroxymethylating reagent is described. The corresponding products can be obtained in good to excellent yield. A number of aryl aldehydes can also be used in place of paraformaldehyde giving the desired alcohol products with similarly good results.
- Zhang, Guo-Fu,Li, Yue,Xie, Xiao-Qiang,Ding, Cheng-Rong
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supporting information
p. 1216 - 1219
(2017/03/14)
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- Copper-mediated C-H cyanation of (hetero)arenes with ethyl (ethoxymethylene)cyanoacetate as a cyanating agent
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A copper-mediated direct C-H cyanation of (hetero)arenes with ethyl (ethoxymethylene)cyanoacetate as a safe cyanating agent has been successfully developed by using molecular oxygen as the oxidant. The reaction tolerates a variety of functional groups and provides a facile and efficient method for the synthesis of a wide range of (hetero)aryl nitriles.
- Qi, Chaorong,Hu, Xiaohan,Jiang, Huanfeng
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p. 7994 - 7997
(2017/07/22)
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- SILICON-BASED CROSS COUPLING AGENTS AND METHODS OF THEIR USE
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Compositions and methods using silicon-based cross-coupling agents in the formation of carbon-carbon and carbon-nitrogen bonds are described.
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Paragraph 0071
(2016/02/10)
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- Synthesis, Properties, and Light-Emitting Electrochemical Cell (LEEC) Device Fabrication of Cationic Ir(III) Complexes Bearing Electron-Withdrawing Groups on the Cyclometallating Ligands
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The structure-property relationship study of a series of cationic Ir(III) complexes in the form of [Ir(C^N)2(dtBubpy)]PF6 [where dtBubpy = 4,4′-di-tert-butyl-2,2′-bipyridine and C^N = cyclometallating ligand bearing an electron-withdrawing group (EWG) at C4 of the phenyl substituent, i.e., -CF3 (1), -OCF3 (2), -SCF3 (3), -SO2CF3 (4)] has been investigated. The physical and optoelectronic properties of the four complexes were comprehensively characterized, including by X-ray diffraction analysis. All the complexes exhibit quasireversible dtBubpy-based reductions from -1.29 to -1.34 V (vs SCE). The oxidation processes are likewise quasireversible (metal + C^N ligand) and are between 1.54 and 1.72 V (vs SCE). The relative oxidation potentials follow a general trend associated with the Hammett parameter (σ) of the EWGs. Surprisingly, complex 4 bearing the strongest EWG does not adhere to the expected Hammett behavior and was found to exhibit red-shifted absorption and emission maxima. Nevertheless, the concept of introducing EWGs was found to be generally useful in blue-shifting the emission maxima of the complexes (λem = 484-545 nm) compared to that of the prototype complex [Ir(ppy)2(dtBubpy)]PF6 (where ppy = 2-phenylpyridinato) (λem = 591 nm). The complexes were found to be bright emitters in solution at room temperature (φPL = 45-66%) with microsecond excited-state lifetimes (e = 1.14-4.28 μs). The photophysical properties along with density functional theory (DFT) calculations suggest that the emission of these complexes originates from mixed contributions from ligand-centered (LC) transitions and mixed metal-to-ligand and ligand-to-ligand charge transfer (LLCT/MLCT) transitions, depending on the EWG. In complexes 1, 3, and 4 the 3LC character is prominent over the mixed 3CT character, while in complex 2, the mixed 3CT character is much more pronounced, as demonstrated by DFT calculations and the observed positive solvatochromism effect. Due to the quasireversible nature of the oxidation and reduction waves, fabrication of light-emitting electrochemical cells (LEECs) using these complexes as emitters was possible with the LEECs showing moderate efficiencies.
- Pal, Amlan K.,Cordes, David B.,Slawin, Alexandra M. Z.,Momblona, Cristina,Ort?, Enrique,Samuel, Ifor D. W.,Bolink, Henk J.,Zysman-Colman, Eli
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p. 10361 - 10376
(2016/10/26)
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- Palladium-Catalyzed Decarbonylative Cross-Coupling of Azinecarboxylates with Arylboronic Acids
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The first palladium-catalyzed decarbonylative coupling of phenyl 2-azinecarboxylates and arylboronic acids is presented. The key for the development of this decarbonylative coupling is the use of Pd/dcype as a catalyst. A wide range of 2-azinecarboxylates can undergo the present coupling reaction to afford 2-arylazines. By combination with previously reported nickel-catalyzed decarbonylative coupling, we achieved a chemoselective sequential decarbonylative coupling of pyridine dicarboxylate to synthesize 2,4-diarylpyridine.
- Muto, Kei,Hatakeyama, Taito,Itami, Kenichiro,Yamaguchi, Junichiro
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supporting information
p. 5106 - 5109
(2016/10/14)
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- Chemoselective Synthesis of Polysubstituted Pyridines from Heteroaryl Fluorosulfates
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A selection of heteroaryl fluorosulfates were readily synthesized using commercial SO2F2 gas. These substrates are highly efficient coupling partners in the Suzuki reaction. Through judicious selection of Pd catalysts the fluorosulfate functionality is differentiated from bromide and chloride; the order of reactivity being: -Br> -OSO2F> -Cl. Exploiting this trend allowed the stepwise chemoselective synthesis of a number of polysubstituted pyridines, including the drug Etoricoxib. A selection of heteroaryl fluorosulfates were readily synthesized using commercial SO2F2 gas. These substrates are highly efficient coupling partners in the Suzuki reaction. Through judicious selection of Pd catalysts the fluorosulfate functionality is differentiated from bromide and chloride; the order of reactivity being: -Br> -OSO2F> -Cl. Exploiting this trend allowed the stepwise chemoselective synthesis of a number of polysubstituted pyridines, including the drug Etoricoxib.
- Zhang, Enxuan,Tang, Jiaze,Li, Suhua,Wu, Peng,Moses, John E.,Sharpless, K. Barry
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supporting information
p. 5692 - 5697
(2016/04/20)
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- Design, Synthesis, and Validation of an Effective, Reusable Silicon-Based Transfer Agent for Room-Temperature Pd-Catalyzed Cross-Coupling Reactions of Aryl and Heteroaryl Chlorides with Readily Available Aryl Lithium Reagents
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A reusable silicon-based transfer agent (1) has been designed, synthesized, and validated for effective room-temperature palladium-catalyzed cross-coupling reactions (CCRs) of aryl and heteroaryl chlorides with readily accessible aryl lithium reagents. The crystalline, bench-stable siloxane transfer agent (1) is easily prepared via a one-step protocol. Importantly, this green CCR protocol circumvents prefunctionalization, isolation of organometallic cross-coupling partners, and/or stoichiometric waste aside from LiCl. DFT calculations support a σ-bond metathesis mechanism during transmetalation and lead to insights on the importance of the CF3 groups.
- Martinez-Solorio, Dionicio,Melillo, Bruno,Sanchez, Luis,Liang, Yong,Lam, Erwin,Houk,Smith, Amos B.
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p. 1836 - 1839
(2016/03/01)
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- Visible light-induced aerobic C-N bond activation: A photocatalytic strategy for the preparation of 2-arylpyridines and 2-arylquinolines
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An efficient method for accessing arylpyridines and arylquinolines via visible light-induced aerobic C-N bond activation is described. The applicability of different kinds of simple ketones, easily available amines, and the use of air as the sole oxidant make this transformation very attractive.
- Hu, Bei,Li, Yuyuan,Dong, Wuheng,Xie, Xiaomin,Wan, Jun,Zhang, Zhaoguo
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p. 48315 - 48318
(2016/06/09)
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- Based on pyridine ring metal-ligand-platinum complex and its preparation method and application
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The invention relates to a novel cyclometal ligand-platinum complex and a preparation method and application thereof, and belongs to the technical field of electronic materials. The novel cyclometal ligand-platinum complex is convenient in template design and easy to obtain. Triphenylaminyl, quinolyl and trifluoromethyl are introduced in a material, and the electron structure and the hole injection and transmission performance of the material can be conveniently adjusted by adjusting substituents on an aza heteroaromatic ring. The complex provided by the invention is good in thermal stability and hole injection and transmission performance, and has wide application prospect in the fields of organic electroluminescent materials, oxygen sensing materials, dyes and medicines and the like. The oxygen sensor prepared by the complex has the advantages of simple structure, low cost, reliable work and the like; and the complex can be prepared into a portable oxygen sensor to be popularized and used.
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Paragraph 0078
(2016/11/07)
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- Facile synthesis and complete characterization of homoleptic and heteroleptic cyclometalated Iridium(III) complexes for photocatalysis
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Herein we describe an improved synthesis for homoleptic iridium(III) 2-phenylpyridine based photocatalysts that allows rapid access to these compounds in good to high yields which have recently become a vital component within the field of catalysis. In addition, we synthesized a number of heteroleptic iridium(III) 2-phenylpyridine photocatalysts and report their photophysical and electrochemical properties. The emission energies span the range of 473-560 nm and reduction potentials from -2.27 V to -1.23 V and oxidation potentials ranging from 1.81 V to 0.69 V. Additionally, we provide the calculated excited state properties and comment on the role of these properties in designing catalytic cycles.
- Singh, Anuradha,Teegardin, Kip,Kelly, Megan,Prasad, Kariate S.,Krishnan, Sadagopan,Weaver, Jimmie D.
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- Pincer-Nickel-Catalyzed Cross-Coupling of Aryl Sulfamates with Arylzinc Chlorides
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The nickel N,N,N-pincer complex 2 was demonstrated to effectively catalyze the cross-coupling of aryl sulfamates with arylzinc chlorides under mild conditions. The reaction is suitable for a wide range of substrates, and tolerates various functional groups. A nickel N,N,N-pincer complex effectively catalyzes the cross-coupling of aryl sulfamates with arylzinc chlorides under mild conditions. The reaction is suitable for a wide range of substrates, and tolerates various functional groups.
- Tao, Jian-Long,Wang, Zhong-Xia
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p. 6534 - 6540
(2015/10/19)
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- Silver-catalyzed arylation of (hetero)arenes by oxidative decarboxylation of aromatic carboxylic acids
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A long-standing challenge in Minisci reactions is achieving the arylation of heteroarenes by oxidative decarboxylation of aromatic carboxylic acids. To address this challenge, the silver-catalyzed intermolecular Minisci reaction of aromatic carboxylic acids was developed. With an inexpensive silver salt as a catalyst, this new reaction enables a variety of aromatic carboxylic acids to undergo decarboxylative coupling with electron-deficient arenes or heteroarenes regardless of the position of the substituents on the aromatic carboxylic acid, thus eliminating the need for ortho-substituted aromatic carboxylic acids, which were a limitation of previously reported methods.
- Kan, Jian,Huang, Shijun,Lin, Jin,Zhang, Min,Su, Weiping
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supporting information
p. 2199 - 2203
(2015/02/19)
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- Aerobic C-N bond activation: A simple strategy to construct pyridines and quinolines
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Inspired by the autoxidation processes, a dioxygen induced C-N bond activation of primary alkyl amines was demonstrated toward the synthesis of pyridines and quinolines. The transition-metal free conditions with O2 as the sole oxidant make this transformation very attractive. Notably, the substrate applicability of different kinds of ketones is greatly broadened for this transformation.
- Wu, Kun,Huang, Zhiliang,Liu, Chao,Zhang, Heng,Lei, Aiwen
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supporting information
p. 2286 - 2289
(2015/02/05)
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- Trifluoromethyl-substituted cyclometalated iridiumIII emitters with high photostability for continuous oxygen sensing
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Trifluoromethyl-substituted cyclometalated Ir(III) complexes have been prepared and fully characterized. The photophysical and electrochemical properties of the complexes were investigated systematically. All iridium complexes exhibit high photoluminescence quantum yields, high oxidation potentials and good photostability against continuous irradiation. The optimum loading level of the Ir(III) complexes incorporated into oxygen-sensitive films has been discussed. Three different polymers were investigated for the development of efficient oxygen-sensitive films. All Ir(III) complexes immobilized in ethyl cellulose demonstrated quick responses to various oxygen concentrations and high sensitivity upon changes of oxygen partial pressure. These cyclometalated Ir(III) complexes with high photostability are potential candidates for online continuous monitoring of oxygen concentrations.
- Liu, Chun,Lv, Xin,Xing, Yang,Qiu, Jieshan
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supporting information
p. 8010 - 8017
(2015/08/06)
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- Catalytic Electrophilic C-H Silylation of Pyridines Enabled by Temporary Dearomatization
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A C-H silylation of pyridines that seemingly proceeds through electrophilic aromatic substitution (SEAr) is reported. Reactions of 2- and 3-substituted pyridines with hydrosilanes in the presence of a catalyst that splits the Si-H bond into a hydride and a silicon electrophile yield the corresponding 5-silylated pyridines. This formal silylation of an aromatic C-H bond is the result of a three-step sequence, consisting of a pyridine hydrosilylation, a dehydrogenative C-H silylation of the intermediate enamine, and a 1,4-dihydropyridine retro-hydrosilylation. The key intermediates were detected by 1H NMR spectroscopy and prepared through the individual steps. This complex interplay of electrophilic silylation, hydride transfer, and proton abstraction is promoted by a single catalyst.
- Wübbolt, Simon,Oestreich, Martin
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supporting information
p. 15876 - 15879
(2016/01/28)
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- Catalytic meta-selective C-H functionalization to construct quaternary carbon centres
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A catalytic meta-selective C-H functionalization of 2-phenylpyridines using a range of tertiary halides is described. The protocol is simple to perform and uses commercially available reagents to construct challenging quaternary carbon centres in a regioselective manner. Preliminary studies suggest the C-H functionalization proceeds through a radical process directed via a remote σ-activation.
- Paterson, Andrew J.,St John-Campbell, Sahra,Mahon, Mary F.,Press, Neil J.,Frost, Christopher G.
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supporting information
p. 12807 - 12810
(2015/08/06)
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- Cobalt-catalyzed C-H cyanation of (Hetero)arenes and 6-Arylpurines with N -cyanosuccinimide as a new cyanating agent
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A cobalt-catalyzed C-H cyanation reaction of arenes has been developed using N-cyanosuccinimide as a new electrophilic cyanating agent. The reaction proceeds with high selectivity to afford monocyanated products with excellent functional group tolerance. Substrate scope was found to be broad enough to include a wide range of heterocycles including 6-arylpurines.
- Pawar, Amit B.,Chang, Sukbok
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supporting information
p. 660 - 663
(2015/03/04)
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