Homogeneous Hydrogenation Catalysts Research Articles

A facile method for the preparation of 2,4-bis(diphenylphosphino)pentane (BDPP) enantiomers and their application in asymmetric hydrogenation

Asymmetric heterogeneous hydrogenation of acetylacetone was applied for the preparation of both enantiomers (2 R,4 R and 2 S,4 S) of 2,4-bis(diphenylphosphino)pentane (BDPP). Among the chiral phosphines prepared up to now BDPP appears to be unique in the sense that its rhodium(I) complexes serve as effective homogeneous asymmetric hydrogenation catalysts not only for the reduction of Z-α-amidoacrylic acids but also for the reduction of α-ethylstyrene, acetophenone, and acetophenonebenzylimine. The analogous phosphinite ligand BDPOP yields a less selective catalyst.

(η 6-Arene)(η 4-cycloocta-1,5-diene)ruthenium(0) complexes as homogeneous hydrogenation catalysts

Ru(η 6-arene)(η 4-COD) complexes (COD = cycloocta-1,5-diene) have been found to be catalytic precursors for the homogeneous hydrogenation of α-olefins and cycloolefins under mild conditions (room temperature, P(H 2) 1–20 atm).

Homogeneously catalyzed hydrogenation and gas‐liquid chromatographic analysis of the methyl esters of cyclopropene fatty acids

AbstractVarious concentrations of cyclopropene fatty acids have been determined down to 0.2% by the use of gas liquid chromatographic (GLC) analysis of the methyl esters of fatty acids that have been quantitatively hydrogenated using a homogeneous transition metal complex catalyst. The effectiveness of the use of bromotris(triphenylphosphine)‐rhodium(I), Br(P(C6H5)3)3Rh, as a homogeneous hydrogenation catalyst to convert the cyclopropene ring to a cyclopropane ring has been evaluated and compared with the analogous chloro‐ and iodo‐complexes. The hydrogenation/GLC method of analysis has been compared with the method of titration with hydrogen bromide in benzene and with the method involving the use of high resolution nuclear magnetic resonance (NMR).

Comparison of homogeneous and heterogeneous palladium hydrogenation catalysts

AbstractMechanistic and kinetic studies of Pd‐catalyzed hydrogenation at atmospheric pressure and 30–100 C were carried out with methyl sorbate, methyl linoleate and conjugated linoleate. Homogeneous Pd catalysts and particularly Pd‐acetylacetonate [Pd(acac)2] were significantly more selective than Pd/C in the hydrogenation of sorbate to hexanoates, mainlytrans‐2‐hexenoate. Relative rate constants for the different parallel and consecutive reactions, determined by computer simulation, indicated that the low diene selectivity of Pd/C can be dattributed to a significant direct reduction of sorbate to hexanoate. The similar behavior of PdCl2 to that of Pd/C suggests that Pd(II) was initially reduced to Pd(O). Valence stabilization of PbCl2 by adding DMF or a mixture of Ph3P and SnCl2 increased the diene selectivity but decreased the activity. Stabilization of Pd(acac)2 with triethylaluminum (Ziegler catalyst) resulted in increased activity but decreased selectivity. The kinetics of methyl linoleate hydrogenation showed that although Pd(acac)2 was only half as active as Pd/C, their respective diene selectivity was similar (10.4 and 9.6). The much greater reactivity of conjugated compared with unconjugated linoleate toward Pd(acac)2 suggests the possible formation of conjugated dienes as intermediates that are rapidly reduced and not detected in the lipid phase during hydrogenation.

Phospholipid studies of marine organisms 9. New brominateddemospongic acids from the phospholipids of two [formula omitted] species

Two Novel long chain fatty acids, (5Z, 9Z)-6-bromo-25-methyl-5,9-hexacosadienoic and (5Z, 9Z)-6-bromo-24-methyl-5,9-hexacosadienoic acids were found in the phospholipids of Petrosia ficiformis and P. hebes . Their structures were elucidated with the help of CI-EI7MS and a homogeneous hydrogenation catalyst.

EXAFS investigation of nickel and cobalt precursors of homogeneous ziegler-type hydrogenation catalysts

A preliminary EXAFS study is reported of precursors of homogeneous hydrogenation catalysts obtained by addition of AlEt3 to nickel or cobalt octoate solutions in benzene. For a given nickel octoate solution studied before reduction, monodentate coordination of the nickel cations to at least four carboxylic anions was established and accurate Ni...O1, Ni...C1 distances (i.e. 2.06±0.01 Å, 3.01±0.02 Å) were determined. The spectra of the reduced solutions are however clearly dominated by intense Ni*...Ni or Co*...Co signals at distances comparable to the relevant distances of the bulk metal, and thus suggest the presence of rather disordered, amorphous-like metal clusters. Strong evidence is also produced in favour of additional metal...carbon bonds which were often assumed to play an important role in the catalytic activity of these or related solutions.

Asymmetric hydrogenation using chiral phosphinite rhodium complexes

The Cu(I) complex of (1R,3R)-bis(diphenylphosphinoxy)-1,3-diphenylpropane (BDPODP) has been prepared and used for the transfer of the ligand to Rh(I). The Rh(I) complexes of this new phosphinite obtained by this method act as efficient asymmetric homogeneous hydrogenation catalysts for (Z)-α-(acylamino)-cinnamic acids.

Equilibration of ortho- and para-hydrogen by homogeneous hydrogenation catalysts in solution; A test for the reversibility of hydrogen addition using Raman spectroscopy

Abstract para -Enriched hydrogen is converted into the ortho - para equilibrium mixture by tris(triphenylphosphine)rhodium chloride in toluene solution. The rotational Raman effect can be used to show that this equilibration occurs during the course of hydrogenation of cyclohexene by the above catalyst. The methanol solvate formed by reduction of 1,4-bis(diphenylphosphino)butanebicyclo[2.2.1] heptadienerhodium tetrafluoroborate also catalyses the ortho - para equilibration of hydrogen, in common with related cationic rhodium complexes. No equilibration occurs, however, during the course of hydrogenation of ( Z )-α-benzamidocinnamic acid by cationic chelate rhodium complexes, including that derived from the chiral ligand ( R , R )-1,2-bis( o -methoxyphenylphenyl)ethane (DIPAMP), thus demonstrating that addition of hydrogen to rhodium is irreversible.

1,4:3,6-dianhydro-2,5-dideoxy-2,5-bis(diphenylphosphino)- l-iditol. A new chiral ligand for asymmetric hydrogenation with rhodium complexes as catalysts

A new chiral 1,4-diphosphine, 1,4:3,6-dianhydro-2,5-dideoxy-2,5-bis(diphenylphosphino)- l-iditol, has been prepared from d-mannitol. Rhodium complexes of this ligand are asymmetric homogeneous hydrogenation catalysts for dehydroamino acids, giving ( S)-amino acids in 21–58% optical yields.

Catalytic properties of chloro-tris[tri(2-thienyl)phosphine]-rhodium(I) in hydrogenation of unsaturated compounds

1. The thiophene analog of the Wilkinson complex was synthesized and it was shown that the concept of isosterism can serve as one of the criteria for seeking new homogeneous hydrogenation catalysts. 2. The catalytic properties of the thienyl analog of the Wilkinson complex were studied in the homogeneous hydrogenation of allyl alcohol, allylbenzene, and α-acetamidocinnamic acid.

Asymmetric hydrogenation catalyzed by aminophosphine-phosphiniterhodium complexes derived from natural aminoalcohols and x-ray crystal structure of (1,5-cyclooctadiene)-( S)- N-(diphenylphosphino)-2-diphenylphosphinoxymethylpyrrolidinerhodium(I) perchlorate

From the cheap and readily available amino alcohols ( S)-pyrrolidinemethanol (( S)-prolinol), and ( S)-α- N-ethyl-aminobutanol, we have obtained two new aminophosphine-phosphinite ligands: ( S)- N-(diphenylphospino)-2-diphenylphos- phinooxymethylpyrrolidine (( S)-Prolophos) and ( S)-1-diphenylphosphinoxy-2- N-ethyl- N-diphenylphosphinoaminobutane (( S)-Butaphos). The rhodium(I) complexes of these phosphines act as efficient homogeneous hydrogenation catalysts at ambient temperature and pressures for dehydro N-acetyl amino acids, dehydro N-benzoyl amino acids and itaconic acid. An X-ray diffraction study of the complex [Rh(COD)(( S)-Prolophos)][ClO 4]· THF has been shown that the crystals belong to the monoclinic space group P2 1 with a 10.680(2), b 10.448(2), c 18.207(3) Å and β 104.97(1)ldg. Refinements based on 2105 significant counter reflections led to a final R value of 0.060. The cation is in a distorted square planar geometry, the rhodium atom being bound to the two phosphorus atoms and to the two double bonds of the diene molecule.

ChemInform Abstract: A HOMOGENEOUS CATALYST FOR HYDROGENATION: PALLADIUM(II) CHLORIDE IN DICHLOROMETHANE WITH POLYETHYLENE GLYCOL (PEG)

Chemischer InformationsdienstVolume 14, Issue 25 Preparative Organic Chemistry ChemInform Abstract: A HOMOGENEOUS CATALYST FOR HYDROGENATION: PALLADIUM(II) CHLORIDE IN DICHLOROMETHANE WITH POLYETHYLENE GLYCOL (PEG) N. SUZUKI, N. SUZUKISearch for more papers by this authorY. AYAGUCHI, Y. AYAGUCHISearch for more papers by this authorY. IZAWA, Y. IZAWASearch for more papers by this author N. SUZUKI, N. SUZUKISearch for more papers by this authorY. AYAGUCHI, Y. AYAGUCHISearch for more papers by this authorY. IZAWA, Y. IZAWASearch for more papers by this author First published: June 21, 1983 https://doi.org/10.1002/chin.198325151Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume14, Issue25June 21, 1983 RelatedInformation

Mechanistic aspects of a homogeneous carbon monoxide hydrogenation catalyst - tetrairidium dodecacarbonyl in molten aluminum chloride-sodium chloride

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMechanistic aspects of a homogeneous carbon monoxide hydrogenation catalyst - tetrairidium dodecacarbonyl in molten aluminum chloride-sodium chlorideJames P. Collman, John I. Brauman, Gerald Tustin, and Grady S. Wann IIICite this: J. Am. Chem. Soc. 1983, 105, 12, 3913–3922Publication Date (Print):June 1, 1983Publication History Published online1 May 2002Published inissue 1 June 1983https://doi.org/10.1021/ja00350a029RIGHTS & PERMISSIONSArticle Views247Altmetric-Citations21LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

Le complexe [{PtCl 2(triméthyl-2,4,6-pyridine)} 2] catalyseur homogene d'hydrogenation et d'hydrosilylation d'olefines et d'aldehydes et cetones α,β-insatures

The chloro-bridged platinum(II) complex dichlorobis(2,4,6-trimethylpyridine)-platinum was found to be an active catalyst for homogeneous hydrogenation and hydrosilylation of olefins and α,β-unsaturated aldehydes and ketones at room temperature and under atmospheric pressure. Hydrosilylation of terminal olefins can be achieved with dimethylphenylsilane and a catalyst/reactant ratio of 10 −6/1. This complex is the first example of a platinum(II) compound containing pyiridine ligands having good catalytic activity possibilities.

Homogeneous hydrogenation of alk-1-enes and alkynes catalyzed by the 1-[Ir(CO)(PhCN)(PPh 3)]-7-C 6H 5-1,7-(σ-C 2B 10H 10) complex

The complex [Ir(σ-carb)(CO)(PhCN)(PPh 3)], where carb = -7-C 6H 5-1,2C 2B 10H 10, was found to be an effective catalyst for homogeneous hydrogenation of terminal olefins and acetylenes at room temperature and atmospheric or subatmospheric hydrogen pressure. Internal olefins are not hydrogenated, but simple alk-1-enes are readily converted into the corresponding alkanes. Isomerization of the double bond catalyzed by the metal complex occurs at very small extent. Catalytic hydrogenation of olefins having carboxylate substituents on the unsaturated carbon atoms is prevented by the formation of thermally stable chelate hydridoalkyl complexes of the type I (H) (σ-CHRCHR′C(O)OR″) (σ-carb)(CO)(PPh 3)]. Acetylenes are hydrogenated to alkenes. The alk-1-enes formed in the hydrogenation of the alkynes HCCR in turn undergo the more slow reactions either of hydrogenation to alkanes or isomerization to internal olefins which cannot be further hydrogenated. Hydrogenation of alkynes of the type RCCR′ is stereospecifically cis, yielding cis- olefins. Catalyzed cis → trans isomerization reaction of these internal olefins occurs only to a negligeable extent.

Spectroscopic Characterization of Wilkinson's Catalyst Using X-ray Photoelectron Spectroscopy (ESCA)

Wilkinson's catalyst, RhCl(PPh3)3 is a well known and widely used homogeneous hydrogenation catalyst. This catalyst was analyzed by ESCA which revealed that two rhodium species [Rh(I) and Rh(III)] were present, both for commercial preparations and for catalysts prepared in this laboratory. The ratio of Rh(I) to Rh(III) was 3:2 regardless of the source. A different method of synthesizing RhCl(PPh3)3 was used and produced a compound having only Rh(I) species. Additional analytical techniques such as elemental analysis, FT-IR, liquid chromatography, and 31P NMR were used to determine the origin of the higher binding energy peaks when Wilkinson's procedure was used to prepare RhCl(PPh3)3. Hydrogenation of cyclohexene was also performed to determine the effect of the higher binding energy species on catalytic activity.

Correction. Poly(tertiary Phosphines and Arsines). 17. Poly(tertiary Phosphines) Containing Terminal Neomethyl Groups as Ligands in Asymmetric Homogeneous Hydrogenation Catalysts

Correction. Poly(tertiary Phosphines and Arsines). 17. Poly(tertiary Phosphines) Containing Terminal Neomethyl Groups as Ligands in Asymmetric Homogeneous Hydrogenation Catalysts

Selective conjugation of soybean esters to increase hydrogenation selectivity

AbstractPolyunsaturated fatty acid methyl esters of soybean oil (MeSBO) were selectively conjugated as a means of increasing the linolenate selectivity of various homogeneous and heterogeneous hydrogenation catalysts. Kinetics of the conjugation reaction in various solvents indicated that linolenate conjugated 5–8 times faster than linoleate. Selective conjugation of MeSBO with potassiumt‐butoxide in dipolar solvents resulted in an increase in linolenate hydrogenation selectivity to 7–8 with Ni and Pd heterogeneous catalysts, and to 7–10 with homogeneous and heterogeneous chromium carbonyl catalysts.Trans‐unsaturation in the hydrogenated products was only 1–3% with the chromium carbonyl catalysts, in contrast to 30–39% with the heterogeneous metal catalysts. Triglycerides were readily converted to partial glycerides andt‐butyl esters with the potassiumt‐butoxide reagent.

Chiral Recognition in Catalytic Hydrogenation of α-Acylaminoacrylic Acids by Cationic Rhodium(I) Complexes of Chiral Aminophosphines Derived from (R,R)-1,2-Cyclohexanediamine or (R)-1,2-propanediamine

Abstract Four chiral diphosphines, (R,R)-1,2-bis[N-methyl(diphenylphosphino)arnino]cyclohexane, (R,R)-1,2-bis[(diphenylphosphino) amino] cyclohexane, (R)-1,2-bis[N-methyl(diphenylphosphino)amino]propane, and (R)-1,2-bis[(diphenylphosphino)amino] propane have been prepared from the corresponding optically active diamines. The cationic 1,5-cyclooctadiene rhodium(I) complexes with these diphosphines act as effective homogeneous catalysts for the stereoselective hydrogenation of α-acylaminoacrylic acids. The optical yields and the absolute configurations of the products depend on the kind of diphosphine ligands. The (R,R)-1,2-bis[N-methyl(diphenylphosphino)amino]cyclohexane complex catalyst yields N-benzoyl-(S)-leucine, N-benzoyl-(S)-phenylalanine, and N-acetyl-(S)-phenylalanine in 94, 92, and 89% e.e., respectively. The other three catalysts are less effective (6–74% e.e.). The aminophosphine complexes with methyl groups on the nitrogen atoms always give (S)-amino acids, those with no methyl group (R)-amino acids. Such a difference in the chiral recognition has been discussed on the basis of circular dichroism spectra and Dreiding molecular models of the rhodium(I) complexes.

Der cluster H 3Ni 4(C 5H 5) 4 als selektiver hydrierungskatalysator

Zusammenfassung The cluster compound H3Ni4(C5H5)4 acts as a catalyst for homogeneous hydrogenation of sterically non-hindered, presumably terminal, olefinic double bonds. The μ3-hydrido ligands are not involved in the catalytic process. The catalytic activity of the cluster is markedly related to its structure.