1208-86-2Relevant academic research and scientific papers
Allyl Palladium Complexes of Cycloheptatrienyl-Cyclopentadienyl Phosphane Ligands in Buchwald-Hartwig Amination Reactions
Tr?ndle, Sabrina,Freytag, Matthias,Jones, Peter G.,Tamm, Matthias
, (2019)
A series of well-defined palladium allyl chloride pre-catalysts was synthesized using previously reported troticenyl phosphane ligands [(η7-C7H7)Ti(η5-C5H4PR2)] and [(η7-C7H6PR2)Ti(η5-C5H5)] (R = Cy, tBu) as ancillary ligands. The formation of a dimeric μ-chloro-, μ-allyl-bridged PdI species was observed with the ligand [(η7-C7H7)Ti(η5-C5H4PtBu2)], whereas L2Pd0 {L = [(η7-C7H6PtBu2)Ti(η5-C5H5)]} was formed in presence of KOtPent. In addition, the catalytic activity of the palladium allyl chloride pre-catalysts was investigated in Buchwald-Hartwig amination reactions with various aryl halogenides and N-methylaniline or morpholine. The cyclohexyl derivatives show almost no catalytic activity, whereas for the tert-butyl derivatives a significant difference could be observed, depending on whether the seven-membered ring or the five-membered ring is functionalized.
Microwave-assisted copper promoted N-arylation of amines with aryl boronic acids/salts on a KF-alumina surface
Das, Pralay,Basu, Basudeb
, p. 2177 - 2184 (2004)
An experimentally simple microwave-assisted solvent-free N-arylation of primary amines with sodium tetraphenylborate or arylboronic acids, promoted by inexpensive cupric acetate, on the surface of KF-alumina is reported. The reaction is selective for mono-N-arylation, and a variety of functional groups are tolerated in the process.
Mechanistic studies of the palladium-catalyzed amination of aryl halides and the oxidative addition of aryl bromides to Pd(BINAP)2 and Pd(DPPF)2: An unusual case of zero-order kinetic behavior and product inhibition
Alcazar-Roman, Luis M.,Hartwig, John F.,Rheingold, Arnold L.,Liable-Sands, Louise M.,Guzei, Ilia A.
, p. 4618 - 4630 (2000)
Mechanistic studies of the amination of aryl bromides catalyzed by palladium complexes containing the chelating phosphines BINAP and DPPF are reported. The coupling of primary alkyl- and arylamines, secondary cyclic alkylamines, and secondary arylalkylamines with bromoarenes in the presence of stoichiometric base and Pd(BINAP)2 (1a) as catalyst, and the reaction of aniline with 4-Br-C6H4-t-Bu in the presence of base catalyzed by Pd(DPPF)2 (2), were studied. The stoichiometric oxidative additions of PhBr to 1a and to 2 were turnover limiting, and kinetic studies were also conducted on this individual step. The stoichiometric oxidative addition of PhBr to 1a showed an inverse first-order dependence on added ligand when the PhBr concentration was low but depended solely on the rate of chelating ligand dissociation at high [PhBr]. There was no measurable solvent effect. In addition, the rates were indistinguishable in the presence and in the absence of amines and salts that are present in the catalytic amination reactions. Similar qualitative data for the oxidative addition of PhBr to 2 was obtained by 1H NMR spectroscopy. The observed rate constants for the overall amination reactions catalyzed by 1a were shown to be zero order in aryl halide, amine, base, and added ligand, while they were first order in catalyst. These data indicated that the kinetic behavior of the overall reaction was dictated solely by the rate of ligand dissociation from 1a, as observed for the oxidative addition. When secondary amines were used, deviation from this behavior was observed. This anomalous behavior resulted from decay of catalyst rather than a change in the turnover-limiting step. A catalyst decomposition pathway that involves backbone P-C bond cleavage of the chelating bisphosphine ligands was revealed by the stoichiometric oxidative addition studies. Quantitative rate data were also obtained for reaction of 4-Br-C6H4-t-Bu with aniline in the presence of base catalyzed by 2. The observed rate constants were zero order in amine and base, inverse first order in added ligand, and first order in aryl bromide. At low concentration of added ligand, the reaction appeared to be first order in amine. However, this deviation from the expected behavior was due to reversible reaction of the catalyst with product.
Carbazole-bridged double D-A dye for efficient dye-sensitized solar cell
Pramjit, Songyos,Eiamprasert, Utt,Surawatanawong, Panida,Lertturongchai, Pattida,Kiatisevi, Supavadee
, p. 1 - 10 (2015)
A di-anchoring organic dye based on an acceptorπ spacerdonorsecondary donordonorπ spacer acceptor structural motif has been synthesized and used as a sensitizer for dye-sensitized solar cells (DSSCs). The new synthetic approach uses two π spacers, two acceptors and two different donors such as arylamino and carbazole units. The double donoracceptor dye CBZ-3 is linked by a carbazole unit as a secondary donor which increases the donoracceptor strength of the dye and proved to increase the η and Jsc values of the photovoltaic cell compared to the corresponding mono-anchoring system CBZ-2 and the monodonor dye CBZ-1. With the non-planar structure of the arylamino group and the alkyl chains which efficiently prevent the formation of the dye aggregates, the dye exhibited a high open-circuit photovoltage (Voc) of 650 mV, a short-circuit photocurrent density (Jsc) of 7.20 mA cm-2 and the solar energy-to-electricity conversion efficiency (η) of 3.23%.
Phosphine-functionalised polymer resins as Pd scavengers
Guinó, Meritxell,Hii, King Kuok
, p. 6911 - 6913 (2005)
Three phosphine-functionalised polymer resins were used as scavengers of palladium catalysts from Buchwald-Hartwig aryl amination reactions. The purity of the products was assessed, and residual palladium analysed by ICP-AES. Scavenging efficiencies of up to >98.5% were demonstrated.
Dinuclear N-heterocyclic carbene palladium(II) complexes as efficient catalysts for the Buchwald-Hartwig amination
Yang, Jin,Li, Pinhua,Zhang, Yicheng,Wang, Lei
, p. 73 - 78 (2014)
A series of dinuclear N-heterocyclic carbene (NHC) palladium complexes [PdCl2(NHC)]2(μ-L) (1-6, L = diphosphine ligands) has been synthesized and fully characterized by 1H NMR, 13C NMR and 31P NMR spectroscopies, elemental analysis, IR spectroscopy, and X-ray crystal structural study. The solid-state structures of 1-6 show dinuclear frameworks with two palladium(II) centres were held together by bridging diphosphine ligands. Each palladium centre was coordinated by an N-heterocyclic carbene ligand, a phosphorus atom and two chloro ions in a trans-arrangement. Further explorations of the catalytic potential of the dinuclear carbene palladium complexes as catalysts for Pd-mediated transformations have been examined under microwave irradiation conditions and the title complexes (1-6) displayed good catalytic activities in Buchwald-Hartwig aminations of aryl chlorides.
An inexpensive cyclodiphosphazane as an efficient ligand for the palladium-catalyzed amination of aryl bromides and chlorides
Rama Suresh,Kumara Swamy
, p. 6004 - 6007 (2009)
An economic and novel ligand, cyclodiphosphazane [ClPN(t-Bu)]2 (1), was introduced in the palladium-catalyzed amination of unactivated aryl halides. The catalyst allows for the amination of aryl chlorides and bromides with secondary cyclic amines and anilines in good yields.
Tuning Electron-Withdrawing Strength on Phenothiazine Derivatives: Achieving 100 % Photoluminescence Quantum Yield by NO2 Substitution
Chen, Meng-Chi,Lee, Yao-Lin,Huang, Zhi-Xuan,Chen, Deng-Gao,Chou, Pi-Tai
, p. 7124 - 7130 (2020)
The weak fluorescence (quantum yield 2) is a well-known fluorescence quencher. Interestingly, we obtained a highly fluorescent chromophore by combining these two moieties, forming 3-nitrophenothiazine (PTZ-NO2). For comparison, a series of PTZ derivatives bearing electron-withdrawing groups (EWGs; CN and CHO) or electron-donating groups (EDGs; OMe) at the 3-position have been designed and synthesized. The phenothiazines bearing EWGs exhibited enhanced emission compared with the parent PTZ or EDG derivatives. Computational approaches unveiled that for PTZ and PTZ-OMe, the transitions are from HOMOs dominated by π orbitals to LUMOs of mixed sulfur nonbonding–π* orbitals, and hence are partially forbidden. In contrast, the EWGs lower the energy level of the lone-pair electrons on the sulfur atom, thereby suppressing the mixing of the nonbonding orbital with the π* orbital in the LUMO, such that the allowed ππ* transition becomes dominant. This work thus demonstrates a judicious chemical design to fine-tune the transition character in PTZ analogues, with PTZ-NO2 attaining 100 % emission quantum yields in nonpolar solvent.
N(2)-Monosubstituted bishydrazides of oxalic acid as new efficient components of the system for the copper-catalyzed C-N cross-coupling in water
Kurandina,Eliseenkov,Petrov,Boyarskiy
, p. 1009 - 1013 (2012)
N(2)-Monosubstituted bishydrazides of oxalic acid in the presence of hexane-2,5-dione in situ form efficient ligands for the copper catalyzed C-N cross-coupling. A scaled pre-parative method for the synthesis of diarylamines was developed based on the results obtained.
Preparation of polyfunctional amines by the addition of functionalized organomagnesium reagents to nitrosoarenes
Kopp, Felix,Sapountzis, Ioannis,Knochel, Paul
, p. 885 - 887 (2003)
The addition of functionalized arylmagnesium reagents to nitrosoarenes at -20°C in THF furnishes after a reductive work-up polyfunctional diarylamines in 43-74% yield.
