55102-19-7Relevant articles and documents
Olefins isomerization by hydride-complexes of ruthenium
Yue, Chuan Jun,Liu, Ying,He, Ren
, p. 17 - 23 (2006)
Several complexes containing the Ru-H bond were synthesized according to previous reports: RuH(NO)(PPh3)3(I) (1), RuHCl(PPh3)3(s)(II) (2), RuHCl(CO)(PPh3)3(II) (3), RuH(CH3COO)(P
Kinetics and mechanisms of homogeneous catalytic reactions. Part 16. Regioselective hydrogenation of quinoline catalyzed by dichlorotris(triphenylphosphine)ruthenium(II)
Arrieta, Federico,Baricelli, Pablo J.,Fernández, Dángelo,Molina, Karely,Rosales, Merlín
, (2020)
The complex RuCl2(PPh3)3 (1) showed to be an efficient and regioselective precatalyst for the hydrogenation of quinoline (Q) to 1,2,3,4-tetrahydroquinoline (THQ) at P = 5.0–6.5 at m and T = 140?167 °C. This reaction showed to be first order on catalyst concentration and fractional order on dissolved hydrogen concentration (1.84). However, different to other Ru, Os, Rh and Ir precatalysts, the reaction showed an inverse fractional order on Q concentration (-0.44). The rate law may be written as: r = {KoK1k2/(Ko + [Q]+ KoK1[H2])}[Ru][H2]2. Coordination chemistry and theoretical DFT studies allowed us to propose a detailed catalytic cycle for this reaction. Under the hydrogenation conditions, the ruthenium precursor 1 is totally transformed to RuCl2(κN-Q)2(PPh3)2 (3) and subsequently to RuHCl(κN-Q)2(PPh3)2 (4) by heterolytic addition of H2. Complex 4 reversibly dissociates a Q ligand to generate RuHCl(κN-Q)(PPh3)2, which was proposed as the catalytically active species (CAS) entering to the catalytic cycle. The reversible addition of hydrogen yields a species containing a κN-1,2-dihydroquinoline (κN-DHQ) ligand (possibly through the coordination of hydrogen, migration of hydride to the N atom of Q ligand and posterior DHQ reductive elimination); this species suffers a change of coordination mode from κN- to an olefin-like η2-DHQ. Posteriorly, the addition of a second molecule of H2, considered the rate-determining step, generates a THQ species (probably through migration of hydride to C3 of DHQ ligand followed by the heterolytic addition of hydrogen). The cycle is completed by the substitution of the THQ ligand by a new Q molecule, therefore regenerating the CAS.
Homogeneous catalytic hydrogenation. 4. Regioselective reduction of polynuclear heteroaromatic compounds catalyzed by hydridochlorotris(triphenylphosphine)ruthenium(II)
Fish, Richard H.,Tan, John L.,Thormodsen, Arne D.
, p. 1743 - 1747 (1985)
The selective reduction of polynuclear heteroaromatic nitrogen compounds such as quinoline, 1, 5,6-benzoquinoline, 2, 7,8-benzoquinoline, 3, acridine, 4, phenanthridine, 5, and indole, 7, and in one case the sulfur heterocycle benzothiophene, 6, with hydridochlorotris(triphenylphosphine)ruthenium(II) as catalyst, under rather mild hydrogenation conditions, provided in each case the corresponding saturated nitrogen-or sulfur-containing ring compound with reasonable conversion rates and total yields. In addition, it was found that several compounds would inhibit the reduction of 1, to 1,2,3,4-tetrahydroquinoline, 8, including 8 itself, as well as 2, 7, 9 (2-methylpyridine), 10 (3-methylpyridine), and 11 (carbazole). Compounds 3 and 6 did not inhibit the rate of reduction. These inhibitions are seen as effects of competition for binding to the catalyst metal center, this competitive binding being affected by steric constraints and electronic effects such as basicity of the substrates. The substitution of deuterium gas for hydrogen gas in the reduction of 1 provided information on the reversibility of the hydrogenation step and implies a cyclometalation reaction is occurring leading to exchange of the 8-position of the product. Additional deuterium experiments starting with 8 instead of 1 indicate that the catalyst can partially dehydrogenate 8 to form an imine intermediate leading to deuterium exchange at the 2-position.
Coordination, agostic stabilization, and C-H bond activation of N-alkyl heterocyclic carbenes by coordinatively unsaturated ruthenium hydride chloride complexes
Burling, Suzanne,Mas-Marza, Elena,Valpuesta, Jose E. V.,Mahon, Mary F.,Whittlesey, Michael K.
, p. 6676 - 6686 (2009)
The products formed upon reaction of Ru(PPh3)3HCl and [Ru(PiPr3)2HCl]2 with the N-heterocyclic carbenes l,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (I iPr2Me2,1) and 1,3-dieth
A tertiary phosphine that is too bulky: preparation of catalytically less active carbene and vinylidene ruthenium(II) complexes
Stüer, Wolfram,Wolf, Justin,Werner, Helmut
, p. 203 - 207 (2002)
Tricyclooctylphosphine PCoc3 (1), which has been prepared from PCl3 and cyclooctyl Grignard reagent, reacts under an atmosphere of H2 with the dimer [RuCl2(η3:η3 -C10H16/su
Exceedingly Facile Ph-X Activation (X=Cl, Br, I) with Ruthenium(II): Arresting Kinetics, Autocatalysis, and Mechanisms
Miloserdov, Fedor M.,McKay, David,Mu?oz, Bianca K.,Samouei, Hamidreza,MacGregor, Stuart A.,Grushin, Vladimir V.
supporting information, p. 8466 - 8470 (2015/11/27)
[(Ph3P)3Ru(L)(H)2] (where L=H2 (1) in the presence of styrene, Ph3P (3), and N2 (4)) cleave the Ph-X bond (X=Cl, Br, I) at RT to give [(Ph3P)3RuH(X)] (2) and PhH. A combined experimental and DFT study points to [(Ph3P)3Ru(H)2] as the reactive species generated upon spontaneous loss of L from 3 and 4. The reaction of 3 with excess PhI displays striking kinetics which initially appears zeroth order in Ru. However mechanistic studies reveal that this is due to autocatalysis comprising two factors: 1) complex 2, originating from the initial PhI activation with 3, is roughly as reactive toward PhI as 3 itself; and 2) the Ph-I bond cleavage with the just-produced 2 gives rise to [(Ph3P)2RuI2], which quickly comproportionates with the still-present 3 to recover 2. Both the initial and onward activation reactions involve PPh3 dissociation, PhI coordination to Ru through I, rearrangement to a η2-PhI intermediate, and Ph-I oxidative addition.
Mechanistic study on the ruthenium-catalyzed direct amination of alcohols
Pingen, Dennis,Lutz, Martin,Vogt, Dieter
supporting information, p. 1623 - 1629 (2014/05/06)
The Ru-catalyzed direct amination of alcohols with ammonia was investigated for the RuHCl(CO)(PPh3)3/Xantphos system in order to gain mechanistic insight. For several Ru(II) precursor complexes the influence of different additives on catalytic performance was investigated. NMR studies revealed that the reaction of RuHCl(CO)(PPh3)3/Xantphos with the alcohol in the presence of a strong base initially formed an inactive dihydrido Ru species. However, by addition of a ketone, the dihydride was (re)activated, where the corresponding imine is the actual activator, formed by immediate condensation of the ketone with ammonia. In the absence of a base, added ketone significantly enhanced catalyst activity. Catalytically inactive RuCl2(PPh3)3 could be activated by base, demonstrating that also complexes without the CO ligand give active catalysts. On the basis of these observations a mechanism was proposed, closely related to known transfer hydrogenation mechanisms.
A succession of isomers of ruthenium dihydride complexes. Which one is the ketone hydrogenation catalyst?
Abbel, Robert,Abdur-Rashid, Kamaluddin,Faatz, Michael,Hadzovic, Alen,Lough, Alan J.,Morris, Robert H.
, p. 1870 - 1882 (2007/10/03)
Reaction of RuHCl(PPh3)2(diamine) (1a, diamine = (R,R)-1,2-diaminocyclohexane, (R,R)-dach; 1b, diamine = ethylenediamine, en) with KOtBu in benzene quickly generates solutions of the amido-amine complexes RuH(PPh3)2(NHC6H10NH 2), (2a′), and RuH(PPh3)2(NHCH 2CH2NH2), (2b′), respectively. These solutions react with dihydrogen to first produce the trans-dihydrides (OC-6-22)-Ru(H)2(PPh3)2(diamine) (t,c-3a, t,c-3b). Cold solutions (-20°C) containing trans-dihydride t,c-3a react with acetophenone under Ar to give (S)-1-phenylethanol (63% ee). Complexes t,c-3 have lifetimes of less than 10 min at 20° and then isomerize to the cis-dihydride, cis-bisphosphine isomers (OC-6-32)-Ru(H)2(PPh 3)2(diamine) (Δ/Λ-c,c-3a, c,c-3b). A solution containing mainly Δ/Λ-c,c-3a reacts with acetophenone under Ar to give (S)-1-phenylethanol in 20% ee, whereas it is an active precatalyst for its hydrogenation under 5 atm H2 to give 1-phenylethanol with an ee of 50-60%. Complexes c,c-3 isomerize to the cis-dihydride, trans-bisphosphine complexes (OC-6-13)-Ru(H)2(PPh3)2(diamine) (c,t-3a, c,t-3b) with half-lives of 40 min and 1 h, respectively. A mixture of Δ/Λ-c,c-3a and c,f-3a can also be obtained by reaction of 1a with KBH(Busec)3. A solution of complex c,t-3a in benzene under Ar reacts very slowly with acetophenone. These results indicate that the trans-dihydrides t,c-3a or t,c-3b along with the corresponding amido-amine complexes 2a′ or 2b′ are the active hydrogenation catalysts in benzene, while the cis-dihydrides c,c-3a or c,c-3b serve as precatalysts. The complexes RuCl2(PPh3)2((R,R)-dach) or 1a, when activated by KOtBu, are also sources of the active catalysts. A study of the kinetics of the hydrogenation of acetophenone in benzene catalyzed by 3a indicates a rate law: rate = k[c,c-3a]initial[H2] with k = 7.5 M-1 s-1. The turnover-limiting step appears to be the reaction of 2a′ with dihydrogen as it is for RuH(NHCMe 2CMe2NH2)(PPh3)2 (2c′). The catalysts are more active in 2-propanol, even without added base, and the kinetic behavior is complicated. The basic cis-dihydride c,t-3a reacts with [NEt3H]BPh4 to produce the dihydrogen complex (OC-14)-[Ru(η2-H2)(H)(PPh3) 2-((R,R)-dach)]BPh4 (4) and with diphenylphosphinic acid to give the complex RuH(O2PPh2)(PPh3) 2((R,R)-dach) (5). The structure of 5 models aspects of the transition state structure for the ketone hydrogenation step. Complex 2b′ decomposes rapidly under Ar to give dihydrides 3b along with a dinuclear complex (PPh3)2HRu(μ-η2;η4- NHCHCHNH)RuH(PPh3)2 (6) containing a rare, bridging 1,4-diazabutadiene group. The formation of an imine by β-hydride elimination from the amido-amine ligand of 2a′ under Ar might explain some loss of enantioselectivity of the catalyst. The structures of complexes 1a, 5, and 6 have been determined by single-crystal X-ray diffraction.
New N,N-diisopropylcarbamato complexes of ruthenium(II) as catalytic precursors for olefin hydrogenation
Belli Dell'Amico, Daniela,Calderazzo, Fausto,Englert, Ulli,Labella, Luca,Marchetti, Fabio,Specos, Monica
, (2008/10/09)
During the synthesis of [Ru(O2CNiPr2) 2(PPh3)2] (1), the [RuCl2(PPh 3)3]/NHiPr2XCO2 system produces the intermediates [NH2iPr2][Ru2Cl 2(H-Cl)3(PPh3)4] (2) and [RuCl(O2C-NiPr2)(PPh3)3] (3) which have been isolated and fully characterised. Compound 2 contains the dinuclear anionic triply chloride-bridged rathenium(II) species. Compound 3 is mononuclear, the octahedral ruthenium centre being coordinated to the bidentate carbamato ligand. The reactions of compounds 1 and 3 with dihydrogen have been studied at room temperature and atmospheric pressure with respect to their catalytic hydrogenation of 1-octene. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
The kinetic instability of σ-bound aryloxide in coordinatively unsaturated or labile complexes of ruthenium
Snelgrove,Conrad,Yap,Fogg
, p. 268 - 278 (2008/10/08)
Reaction of RuCl2(PPh3)3 (1) or RuHCl(PPh3)3 (2) with KOAr (Ar=4-tBuC6H4) in non-alcohol solvents affords π-aryloxide derivatives Ru(η5-ArO)(o-C6H4PPh2) (PPh3) (3a) or RuH(η5-ArO)(PPh3) 2 (6a), respectively. The phenoxide analogues 3b and 6b are obtained on use of KOPh or TlOPh. Treatment of 1 with 1 equiv. KOAr in the presence of isopropanol liberates the phenol and acetone, affording clean 2 in quantitative yields. In 3:1 methanol-CH2Cl2, RuHCl(CO)(PPh3)3 (4) is also formed in small amounts. Reaction of 1 with 2 KOAr in 20% MeOH-CH2Cl2 affords a mixture of 6a and RuH2(CO)(PPh3)3 (5). In the corresponding reaction of 2 with 1 KOAr, σ-π isomerization of the σ-aryloxide ligand dominates, affording 6a·MeOH as the principal product. Treatment of 6a with ethereal HCl gives [RuH(η6-ArOH)(PPh3)2]Cl (7a); the corresponding reaction of 6b yields RuCl(η5-PhO)(PPh3)2 (8b). The crystal structures of 3a, 3b, 4, 5, 7a, and 8b are reported.
