- Dye-sensitized electron transfer from TiO2 to oxidized triphenylamines that follows first-order kinetics
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Two sensitizers, [Ru(bpy)2(dcb)]2+ (RuC) and [Ru(bpy)2(dpb)]2+ (RuP), where bpy is 2,2′-bipyridine, dcb is 4,4′-dicarboxylic acid-2,2′-bipyridine and dpb is 4,4′-diphosphonic acid-2,2′-bipyridine, were anchored to mesoporous TiO2 thin films and utilized to sensitize the reaction of TiO2 electrons with oxidized triphenylamines, TiO2(e-) + TPA+ → TiO2 + TPA, to visible light in CH3CN electrolytes. A family of four symmetrically substituted triphenylamines (TPAs) with formal Eo(TPA+/0) reduction potentials that spanned a 0.5 eV range was investigated. Surprisingly, the reaction followed first-order kinetics for two TPAs that provided the largest thermodynamic driving force. Such first-order reactivity indicates a strong Coulombic interaction between TPA+ and TiO2 that enables the injected electron to tunnel back in one concerted step. The kinetics for the other TPA derivatives were non-exponential and were modelled with the Kohlrausch-William-Watts (KWW) function. A Perrin-like reaction sphere model is proposed to rationalize the kinetic data. The activation energies were the same for all of the TPAs, within experimental error. The average rate constants were found to increase with the thermodynamic driving force, consistent with electron transfer in the Marcus normal region.
- DiMarco, Brian N.,Troian-Gautier, Ludovic,Sampaio, Renato N.,Meyer, Gerald J.
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p. 940 - 949
(2018/02/07)
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- Effects of solvent and base on the palladium-catalyzed amination: PdCl 2(Ph3P)2/Ph3P-catalyzed selective arylation of primary anilines with aryl bromides
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A readily accessible catalytic system, PdCl2(Ph 3P)2/Ph3P, was developed for the selective arylation of primary anilines with aryl bromides. The strong influence of solvents and bases on the catalytic activity was observed. In refluxing o-xylene, triphenylphosphine shows high efficiency for Pd-catalyzed intermolecular amination reactions. By changing the bases, mono- and diarylation of primary amines could be selectively achieved in high yields. Moreover, the catalytic system showed good toleration for the steric hindrance of anilines. A series of N,N,N′,N′-tetraaryl-1,1′-biphenyl-4,4′- diamines, important intermediates of OLED hole transport materials, were synthesized facilely via coupling reactions between 4,4′-diaminobiphenyls and aryl bromides.
- Cai, Liangzhen,Qian, Xuanying,Song, Wenjing,Liu, Taoping,Tao, Xiaochun,Li, Wanfang,Xie, Xiaomin
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p. 4754 - 4759
(2014/06/24)
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- Selective oxidation of an electronically unsymmetrical distyrylbenzene at either of two sites
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A p-distyrylbenzene bearing electron-withdrawing groups on one terminal ring and electron-supplying groups on the other was synthesized and one ring was found to be significantly more electron rich than the other. Electrochemical oxidative cleavage was sh
- Davis, Anthony P.,Fry, Albert J.
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p. G3091-G3096
(2013/07/05)
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- Selective one-pot synthesis of symmetrical and unsymmetrical di- and triarylamines with a ligandless copper catalytic system
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The one-pot synthesis of symmetrical or unsymmetrical di- or triarylamines using aryl iodides or bromides and LiNH2 as ammonia source is reported. This highly selective method is based, for the first time, on a copper-catalyzed system, which does not require the presence of any additional ligand.
- Tlili, Anis,Monnier, Florian,Taillefer, Marc
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supporting information; experimental part
p. 6408 - 6410
(2012/07/27)
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- Copper-catalyzed synthesis of triarylamines from aryl halides and arylamines
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A simple and efficient methodology for the synthesis of triphenylamines has been demonstrated using copper catalyst with a ligand and tripotassium phosphate as the base. The effect of parameters such as catalyst precursors, ligands, bases and solvents were studied and a series of triphenylamines were obtained with moderate to excellent yields in DMF. This reaction displays great functional groups compatibility in the presence of a broad range of functional groups.
- Qian, Cunwei,Xu, Shaojie,Zong, Qianshou,Fang, Dong
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p. 1881 - 1885
(2012/10/29)
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- Substituent effects on the redox properties and structure of substituted triphenylamines. An experimental and computational study
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The peak oxidation potentials of a series of polysubstituted triphenylamines were found to be highly linearly correlated (R=0.995) with their ionization potentials as computed by density functional theory. The computations, as well as confirming previous
- Wu, Xin,Davis, Anthony P.,Lambert, Peter C.,Kraig Steffen,Toy, Ozan,Fry, Albert J.
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experimental part
p. 2408 - 2414
(2009/07/18)
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- N-ALKYLATION AND N-ARYLATION OF ANILINES STARTING FROM A MILD N-Mg REAGENT: ITS ACTIVATION CAUSING THE 'N-C' COUPLING TO EXTEND THE UNIFIED STRUCTURE-REACTIVITY RELATIONSHIP
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New N-alkylation and N-arylation procedures starting from anilinomagnesium (ArNHMgBr) are reported.For N-alkylation with alkyl bromides, addition of hexamethylphosphoramide to an ArNHMgBr solution in tetrahydrofuran (THF) is effective.After heating at 55 deg C, N-monoalkylation product was obtained in 60-90percent yield, slight dialkylation taking place.The combined use of aryliminodimagnesium with α,ω-dibromoalkanes led to N-arylazacycloalkanes.For N-arylation with iodobenzene, replacement of THF with pyridine and additional use of copper(I) iodide are effective.After heating at 115 deg C with iodobenzene, mono- and diarylation products were obtained, the former being predominant.The combined use of ArNHMgBr and N,N,N',N'-tetramethylethylenediamine as the ligand of copper species is effective for elimination of diarylation and other undesired products, and leads to diarylamines in excellent yield.The method is of advantage over the conventional Ullmann and Chapman methods.The polar solvents and copper salt are effective additives for inducing 'inert combinations' of ArNHMgBr or ArN(MgBr)2 with alkyl and aryl halides into N-C coupling, to extend the unified view proposed for the reactivity of magnesium reagents.The difference in the roles of N-Mg and N-Cu species is discussed.
- Matsuo, Koji,Shichida, Yoshiaki,Nishida, Hiroshi,Nakata, Satsuki,Okubo, Masao
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