23691-27-2Relevant academic research and scientific papers
Radical reactions catalysed by homobimetallic ruthenium(II) complexes bearing Schiff base ligands: Atom transfer radical addition and controlled polymerisation
De Clercq, Bob,Verpoort, Francis
, p. 4687 - 4690 (2002)
The homobimetallic ruthenium Schiff base complexes Ia-f mediated the atom transfer radical addition (ATRA) of carbon tetrachloride across olefins in excellent yields which markedly depended on the catalyst and the substrate used. The best catalytic system Ic is able to compete with the highest performing ruthenium catalysts reported so far for ATRA reactions. In addition these systems are also capable of performing atom transfer radical polymerisation (ATRP) reactions with styrene in high yields and with good control over molecular weight and molecular weight distribution.
Atom transfer radical additions with the cationic half-sandwich complex [Cp*Ru(PPh3)2(CH3CN)]OTf
Quebatte, Laurent,Scopelliti, Rosario,Severin, Kay
, p. 3353 - 3358 (2005)
The cationic ruthenium half-sandwich complex [Cp*Ru(PPh 3)2(CH3CN)][OTf] (2) (Cp* = η5-C5Me5, OTf = SO3CF 3) was synthesized by reduction of [Cp*RuCl2] 2 with zinc in the presence of NaOTf and subsequent reaction with PPh3. When NaOTf was omitted, the corresponding tetrachlorozincate salts were obtained. Complex 2, as well as the salts [Cp*Ru(CH 3CN)3]2[ZnCl4] (3) and [Cp*Ru(PPh3)2-(CH3CN)] 2[ZnCl4] (4), were characterized by single-crystal X-ray analysis. Complex 2 proved to be a potent catalyst for the atom transfer radical addition of CCl4 and CHCl3 to terminal olefins, displaying a performance superior to that of the previously described neutral catalyst [Cp*RuCl(PPh3)2]. For the addition of CHCl3 to styrene, a total turnover number of 890 was achieved. Wiley-VCH Verlag GmbH & Co. KGaA, 2005.
Microwave-enhanced ruthenium-catalysed atom transfer radical additions
Borguet, Yannick,Richel, Aurore,Delfosse, Sébastien,Leclerc, Alain,Delaude, Lionel,Demonceau, Albert
, p. 6334 - 6338 (2007)
The first monomode microwave-assisted atom transfer radical additions (ATRA) of carbon tetrachloride to various olefins were successfully performed, affording the adducts with almost quantitative yields in less than 10 min at 160 °C.
Microwave activation of homogeneous and heterogeneous catalytic reactions
Hajek, Milan
, p. 347 - 354 (1997)
Microwave healing was applied in homogeneous and in heterogeneous reactions and the results were compared from the point of view of activation of chemical reactions. Reactions including the addition of halo compounds to alkenes catalyzed by copper and ruthenium complexes in different solvents and NaY zeolite catalyzed alkylation of secondary amine in the absence of solvent were studied as model reactions to compare possibilities of microwave activation of reactants and catalysts. Rate enhancement of over one order of magnitude in homogeneous reactions was caused mainly by thermal dielectric heating effect which resulted from the effective coupling of microwaves to polar solvents. Activation of reactants and catalysts was very low if any. In heterogeneously catalyzed alkylation reactions highly efficient activation of zeolite catalyst was recorded. The results indicated that the best reaction conditions were in experiments when both activation of catalyst and performance of reaction were carried out under microwave conditions. Rate enhancement was most probably caused by "hot spots" or by "selective heating" of active sites. In both homogeneous and heterogeneous reactions non-thermal activation (specific effect) was excluded.
New pincer-type diphosphinito (POCOP) complexes of NiII and NiIII
Pandarus, Valerica,Zargarian, Davit
, p. 978 - 980 (2007)
This communication reports the synthesis and characterization of the new, pincer-type, square-planar, 16-electron compounds {2,6-(OPPri 2)2C6H3}NiIIBr, 1, and {(Pri2POCH2)2CH}NiIIBr, 2, and the square-pyramidal, 17-electron complex {(Pri 2POCH2)2CH}NiIIIBr2, 3. The Royal Society of Chemistry.
The modulating possibilities of dicarbollide clusters: Optimizing the Kharasch catalysts
Tutusaus, Oscar,Vinas, Clara,Nunez, Rosario,Teixidor, Francesc,Demonceau, Albert,Delfosse, Sebastien,Noels, Alfred F.,Mata, Ignasi,Molins, Elies
, p. 11830 - 11831 (2003)
exo-Cluster dicarbollides substitution has allowed tuning of the E° (Ru(II)/Ru(III)) potential to obtain the best-performing Kharasch catalyst. We postulate that this is possible through the to-and-fro electron movement between the boron cluster and the sulfonium moieties. Copyright
31Cl NQR SPECTRA OF COMPOUNDS IN Cl3CCH2CXRR' SERIES
Feshin, V. P.,Dolgushin, G. V.,Voronkov, M. G.,Gaek, M.,Yanoushek, Z.
, p. 684 - 687 (1990)
In molecules in the series Cl3CCH2CClRR', the substituents R and R' virtually do not affect the chlorine atoms of the Cl3C group, while the NQR frequency of the chlorine atom of the CClRR' group correlates satisfactorily with the ?* constants of these substituents.The regularities observed in the mutual influence of the atoms in the molecules of the studied series indicate that the previously assumed structure of some products of radical telomerization of Cl3CH with H2C=CHCl is erroneous.
Synthesis, Characterization, and Reactivity of PCN Pincer Nickel Complexes
Mousa, Abdelrazek H.,Bendix, Jesper,Wendt, Ola F.
, p. 2581 - 2593 (2018)
New diamagnetic nickel(II) complexes based on an unsymmetrical (1-(3-((ditert-butylphosphino)methyl)phenyl)-N,N-dimethyl-methanamine) (PCN) pincer ligand were synthesized and characterized by 1H, 31P{1H}, and 13C{1H} NMR spectroscopy. Their molecular structures were confirmed by X-ray diffraction. Oxidation to high-valent paramagnetic Ni(III) dihalide complexes was achieved through straightforward reaction of the corresponding diamagnetic halide complexes with anhydrous CuX2 (X = Cl, Br). In agreement with this, the complexes are active in Kharasch addition of CCl4 to olefins. The reaction of the hydroxo complex (8) and the amido complex (11) with CO2 produced the hydrogen carbonate and carbamate complexes, respectively. The hydrogen carbonate complex was converted to the dinuclear nickel carbonate complex (10). The methyl (13), phenyl (14), and p-tolylacetylide (15) complexes are also described in the current study providing the first example of the hydrocarbyl nickel complexes based on an unsymmetric aromatic pincer ligand. Furthermore, the reactivity of the methyl complex toward different electrophiles has been investigated, showing that C-C bond formation is possible with aryl halides, whereas the reaction with CO2 is sluggish.
Kharasch addition catalysed by half-sandwich ruthenium complexes. Enhanced activity of ruthenacarboranes
Tutusaus, Oscar,Delfosse, Sébastien,Demonceau, Albert,Noels, Alfred F.,Vi?as, Clara,Teixidor, Francesc
, p. 8421 - 8425 (2003)
Ruthenium complexes of the type [RuH(η5-CB)(PPh 3)2] {CB is a monoanionic charge-compensated carborane ligand such as [9-SR2-7,8-C2B9H 10]- and [9-SR2-7-CH3-7,8-C 2B9H9]-} efficiently catalyse the Kharasch addition of CCl4 across olefins and, with maximum total turnover numbers of 9000 and initial turnover frequencies of 1900 h -1 at 40°C, highly surpass their Ru-Cp# analogues in these reactions.
Mechanistic and computational studies of the atom transfer radical addition of CCl4 to styrene catalyzed by copper homoscorpionate complexes
Munoz-Molina, Jose Maria,Sameera,Alvarez, Eleuterio,Maseras, Feliu,Belderrain, Tomas R.,Perez, Pedro J.
, p. 2458 - 2467 (2011)
Experimental as well as theoretical studies have been carried out with the aim of elucidating the mechanism of the atom transfer radical addition (ATRA) of styrene and carbon tetrachloride wwith a TpxCu(NCMe) complex as the catalyst precursor (Tpx = hydrotrispyrazolyl-borate ligand). The studies shown herein demonstrate the effect of different variables in the kinetic behavior. A mechanistic proposal consistent with theoretical and experimental data is presented.
