14741-36-7Relevant academic research and scientific papers
In Situ FTIR and NMR Spectroscopic Investigations on Ruthenium-Based Catalysts for Alkene Hydroformylation
Kubis, Christoph,Profir, Irina,Fleischer, Ivana,Baumann, Wolfgang,Selent, Detlef,Fischer, Christine,Spannenberg, Anke,Ludwig, Ralf,Hess, Dieter,Franke, Robert,B?rner, Armin
, p. 2746 - 2757 (2016)
Homogeneous ruthenium complexes modified by imidazole-substituted monophosphines as catalysts for various highly efficient hydroformylation reactions were characterized by in situ IR spectroscopy under reaction conditions and NMR spectroscopy. A proper protocol for the preformation reaction from [Ru3(CO)12] is decisive to prevent the formation of inactive ligand-modified polynuclear complexes. During catalysis, ligand-modified mononuclear ruthenium(0) carbonyls were detected as resting states. Changes in the ligand structure have a crucial impact on the coordination behavior of the ligand and consequently on the catalytic performance. The substitution of CO by a nitrogen atom of the imidazolyl moiety in the ligand is not a general feature, but it takes place when structural prerequisites of the ligand are fulfilled.
RUTHENIUM-CATALYZED ESTERIFICATION OF OLEFIN WITH METHYL FORMATE.
Ueda, W.,Yokoyama, T.,Morikawa, Y.,Moro-Oka, Y.,Ikawa, T.
, p. 197 - 200 (1988)
On the basis of previous findings, we attempted a reaction of methyl formate activated by metal complex with olefin to produce ester, and found that the reaction took place using the ruthenium dihydride complex catalyst, RuH//2 (PPh//3)//4. We will discuss this novel synthetic reaction which has not previously been reported. A catalyst screening was made first by using many kinds of transition metal complexes, in order to discover an effective catalyst for the reaction. As a result, RuH//2(PPh//3)//4 was found to be a unique effective catalyst among the complexes tested, although the reaction conditions used may not have been adequate for catalyst screening. Other catalysts, for example RuH-(CO)(PPh//3)//3, showed some activity but gave very poor results, mainly catalyzing the decomposition of methyl formate.
Photoreactions of the Triruthenium Cluster Ru3(CO)12 and Substituted Analogues
Desrosiers, Marc F.,Wink, David A.,Trautman, Ray,Friedman, Alan E.,Ford, Peter C.
, p. 1917 - 1927 (1986)
Reported is a comprehensive investigation of the medium, ligand, and wavelength effects on the quantum yields and flash photolysis kinetics for the photofragmentation and photosubstitution reactions of the trinuclear ruthenium cluster Ru3(CO)12.Also described are some related studies of the substituted clusters Ru3(CO)12-nLn (L =P(OCH3)3, PPh3, P(p-tolyl)3, or P(O(o-tolyl))3).These results are interpreted in terms of the following model for Ru3(CO)12 photochemistry.Photofragmentation (e.g.Ru3(CO)12 + 3L -> 3Ru(CO)4L) occurs predominantly from the lowest energy excited state and proceeds via an intermediate (I) isomeric to Ru3(CO)12 but not a diradical.I is proposed to have one coordinatively unsaturated ruthenium center trapable by a two-electron donor, i.e., L, to give a second intermediate Ru3(CO)12L which is the precursor to the photofragmentation products.Kinetic flash photolysis observations demonstrate that the lifetime of the latter intermediate is markedly dependent on the nature of L.Photosubstitution reactions (e.g., Ru3(CO)12 + L -> Ru3(CO)11L + CO) are proposed to occur largely from higher energy excited states via CO dissociation to give the unsaturated intermediate Ru3(CO)11, and flash photolysis studies establish the reactivity of this species with various L to follow the order CO > P(OCH3)3 > PPh3.
Pentacarbonyls of ruthenium and osmium. III. Triphenylphosphine-substituted carbonyls of ruthenium and osmium and their reactions with molecular hydrogen
L'Eplattenier,Calderazzo
, p. 1290 - 1293 (1968)
The preparation and characterization of Ru(CO)4P(C6H5)3 and Os(CO)4P(C6H5)3 have been accomplished and a new route to the already known disubstituted Ru(CO)3(P(C6H5)3)2 and Os(CO)3(P(C6H5)3)2 has been found. Reaction with molecular hydrogen on some of these triphenylphosphine-substituted carbonyls has led to OsH2(CO)3P(C6H5)3, RuH2(CO)2(P(C6H5)3) 2, and OsH2(CO)2(P(C6H5)3) 2. For the latter two compounds, the nuclear magnetic resonance and infrared spectra indicate an octahedral structure with both hydrogens in a cis position and the triphenylphosphine substituents in trans positions.
The photochemical generation of novel neutral mononuclear ruthenium complexes and their reactivity
Edwards, Andrew J.,Leadbeater, Nicholas E.,Lewis, Jack,Raithby, Paul R.
, p. 15 - 20 (1995)
The room-temperature photolysis of Ru3(CO)12 (1) in dichloromethane under a flow of ethylene affords the highly reactive complex Ru(CO)4(C2H4) (2) in a quantitative yield.The addition of MeCN to the reaction mixture, while the photolytic conditions and the ethylene flow are maintained, gives Ru(CO)3(C2H4)(NCMe) (3).If the irradiation is continued but the ethylene flow stopped, a different product, namely Ru(CO)3(NCMe)2 (4) is obtained.The addition of an excess of triphenylphosphine to a dichloromethane solution of 2 in the absence of ethylene and of light gives two phosphine-substituted products: Ru(CO)4(PPh3) (5) and Ru(CO)3(PPh3)2 (6).Under similar conditions, 3 affords 6 and the trinuclear cluster Ru3(CO)9(PPh3)3 (7) while, if MeCN is added instead of PPh3, the reactive cluster Ru3(CO)9(NCMe)3 (8) is obtained.If an excess of acrylonitrile is used instead of ethylene, the photolysis of 1 in dichloromethane yields Ru(CO)4(NCCH=CH2) (9) which reacts under photolytic conditions but in the absence of an excess of acrylonitrile with MeCN to give Ru(CO)3(NCCH=CH2)(MeCN) (10) and this product reacts with a second equivalent of acrylonitrile to afford Ru(CO)3(NCCH=CH2)2 (11).All the products have been characterized by IR spectroscopy and their structures established from symmetry considerations.Keywords: Ruthenium; Carbonyl; Nitrile; Photochemical synthesis
Formic acid as a hydrogen storage medium: Ruthenium-catalyzed generation of hydrogen from formic acid in emulsions
Czaun, Miklos,Goeppert, Alain,Kothandaraman, Jotheeswari,May, Robert B.,Haiges, Ralf,Prakash, G. K. Surya,Olah, George A.
, p. 311 - 320 (2014/01/23)
Formic acid is decomposed to H2 and CO2 in the presence of RuCl3 and triphenylphosphines in an emulsion. In situ formed ruthenium carbonyls, such as [Ru(HCO2)2(CO) 2(PPh3)2] (1), [Ru(CO)3(PPh 3)2] (2), and [Ru2(HCO2) 2(CO)4(PPh3)2] (3), and a large cluster, involving a Ru12 core, were identified and structurally characterized from the reaction mixtures. The catalytic activity of the mono and binuclear complexes was also investigated and it was found that [Ru 2(HCO2)2(CO)4(PPh3) 2] (3) shows high stability even at elevated temperatures and pressures and its activity is 1 order of magnitude lower than those measured for the mononuclear complexes. It was also attempted to use [Ru(HCO 2)2(CO)2(PPh3)2] (1) as a catalyst for the hydrogenation of CO2 to formic acid under neutral conditions. Although the reduction of CO2 did not take place, the conversion of [Ru(HCO2)2(CO)2(PPh 3)2] (1) to an unexpected carbonate, [Ru(CO 3)(CO)2(PPh3)2]·H 2O was observed.
Acrylic acid derivatives of group 8 metal carbonyls: A structural and kinetic study
Li, Bo,Kyran, Samuel J.,Yeung, Andrew D.,Bengali, Ashfaq A.,Darensbourg, Donald J.
, p. 5438 - 5447 (2013/06/26)
The synthesis, spectroscopic, and X-ray structural studies of acrylic acid complexes of iron and ruthenium tetracarbonyls are reported. In addition, the deprotonated η2-olefin bound acrylic acid derivative of iron as well as its alkylated species were fully characterized by X-ray crystallography. Kinetic data were determined for the replacement of acrylic acid, acrylate, and methylacrylate for the group 8 metal carbonyls by triphenylphosphine. These processes were found to be first-order in the concentration of metal complex with the rates for dissociative loss of the olefinic ligands from ruthenium being much faster than their iron analogues. However, the ruthenium derivatives afforded formation of primarily mono-phosphine metal tetracarbonyls, whereas the iron complexes led largely to trans-di-phosphine tricarbonyls. This difference in behavior was ascribed to a more stable spin crossover species 3Fe(CO)4 which undergoes rapid CO loss to afford the bis phosphine derivative. The activation enthalpies for dissociative loss of the deprotonated η2-bound acrylic acid ligand were found to be larger than their corresponding values in the protonated derivatives. For example, for dissociative loss of the protonated and deprotonated acrylic acid derivatives of iron(0) the ΔH? values determined were 28.0 ± 1.2 and 34.1 ± 1.5 kcal·mol-1, respectively. Density functional theory (DFT) computations of the bond dissociation energies (BDEs) in these acrylic acids and closely related complexes were in good agreement with enthalpies of activation for these ligand substitution reactions, supportive of a dissociative mechanism for olefin displacement. Processes related to catalytic production of acrylic acid from CO2 and ethylene are considered.
Photochemical synthesis of ruthenium-carbonyl compounds with thioether ligands and subsequent oxidative cleavage of trinuclear complexes by chlorinated solvents
Maiti, Biplab K.,Goerls, Helmar,Klobes, Olaf,Imhof, Wolfgang
, p. 1545 - 1552 (2011/06/22)
The photochemical reaction of [Ru3(CO)12] with thioether ligands in THF leads to the isolation of tetranuclear ruthenium-carbonyl cluster compounds of the formula [Ru4(CO) 13(μ2-R2S)]. In these compounds, ruthenium atoms adopt a typical butterfly arrangement. If chelating ligands with two thioether functions are introduced, the reaction leads to mixtures of the trinuclear substitution products [Ru3(CO)10(RSSR)] and [Ru3(CO)8(RSSR)2]. The latter may be oxidatively cleaved by the use of chlorinated solvents to produce the mononuclear compound [Ru(CO)2Cl2(RSSR)] or the dinuclear complex [Ru2(CO)2(μ2-Cl)2Cl 2(RSSR)2] depending on the reaction conditions. Five new ruthenium-carbonyl-thioether complexes were characterized by X-ray diffraction. Irradiation of [Ru3(CO)12] in THF in the presence of thioether ligands yields ruthenium-carbonyl compounds [Ru4(CO) 13(μ2-R2S)] in the case of monodentate ligands, but [Ru3(CO)10(RSSR)] and [Ru3(CO) 8(RSSR)2] if bidentate thioether ligands are used. The latter may be oxidatively cleaved by CHCl3 to produce the dinuclear complex [Ru2(CO)2(μ2-Cl)2Cl 2(RSSR)2]. Copyright
Ligand-controlled regio- and stereoselective addition of carboxylic acids onto terminal alkynes catalyzed by carbonylruthenium(0) complexes
Tan, Sze Tat,Fan, Wai Yip
, p. 4631 - 4635 (2011/02/27)
The addition of carboxylic acids onto terminal alkynes was catalyzed by mononuclear ruthenium(0) complexes to give enol esters in high yields. By using ligands with different electronic properties, product selectivity was achieved. E-enol esters were preferentially produced when tricarbonyl(η4- diene)ruthenium complexes were used; while geminal enol esters were produced when tricarbonylbis(phosphane)ruthenium complexes were used. Product selectivity is a major problem in transition metal-catalyzed hydrocarboxylation reactions. In this paper we report the ability of Ru(CO)3L2 (where L is a 2 e-donor) to catalyze the addition of variouscarboxylic acids onto terminal alkynes. A direct relationship between the regioselectivity of the product and the electronic property of the catalysis metal centre was observed.
Bis(methimazolyl)silyl complexes of ruthenium
Hill, Anthony F.,Neumann, Horst,Wagler, Joerg
, p. 1026 - 1031 (2010/04/25)
The new bis(methimazolyl)silane PhSiH(mt)2 (mt = methimazolyl), obtained from methimazole (Hmt) and phenyldichlorosilane, reacts with [Ru(η4-C8H12)(η6-C 8H10)] in refiuxing tetra
