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Rhodium Complexes (rhodium + complex)

Distribution by Scientific Domains

Chemistry	95%
2 Other Domains	5%

Distribution within Chemistry

Organic Chemistry	62%
General & Introductory Chemistry	24%
Crystallography	7%
2 Other Subdomains	7%

Selected Abstracts

Asymmetric 1,4-Addition of Organoboron Reagents to Quinone Monoketals Catalyzed by a Chiral Diene/Rhodium Complex: A New Synthetic Route to Enantioenriched 2-Aryltetralones

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4-5 2007
Norihito Tokunaga
Abstract A novel synthetic approach to 2-aryltetralones with high ee has been developed through asymmetric 1,4-addition of arylboronic acids to naphthoquinone monoketals catalyzed by a rhodium complex with the (R,R)-Ph-bod* ligand. The asymmetric addition proceeded in high yields with excellent enantioselectivity. [source]

Highly Regioselective and Rapid Hydroformylation of Alkyl Acrylates Catalyzed by a Rhodium Complex with a Tetraphosphorus Ligand

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2009
Shichao Yu
Abstract Alkyl acrylates have been hydroformylated to the linear aldehydes with high regioselectivity (linear/branch>99/1) and extraordinarily high average turnover frequencies (up to 5400,h,1) by using a rhodium complex with a tetraphosphorus ligand. This protocol is in sharp contrast to the most of other processes that favor production of the branched aldehyde (typically>95% branched for most Rh-catalyzed reaction systems). The high turnover number achieved by this new catalytic system is also remarkable considering the less reactive character of alkyl acrylates to the hydroformylation reaction conditions. [source]

Catalytic Hydrogenation of Norbornadiene by a Rhodium Complex in a Self-Folding Cavitand,

ANGEWANDTE CHEMIE, Issue 41 2010
Dr. Maria Angeles Sarmentero
In Schale geworfen: Die Einführung von [Rh(nbd)2]BF4 (nbd=Norbornadien) in einen Cavitanden mit tiefem Hohlraum ergibt einen Katalysator für die Hydrierung von Norbornadien zu Norbornen (siehe Bild). Der Cavitand wirkt als zweite Ligandensphäre und verändert die Stabilität, Selektivität und Reaktivität gegenüber den Eigenschaften des freien metallorganischen Komplexes in Lösung. [source]

Hydrogenation of Olefins Using Water and Zinc Metal Catalyzed by a Rhodium Complex.

CHEMINFORM, Issue 6 2007
Takashi Sato
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

Transfer Hydrogenation of Isoquinolinium Salts Catalyzed by a Rhodium Complex.

CHEMINFORM, Issue 50 2006
Jiashou Wu
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

Achiral Benzophenone Ligand,Rhodium Complex with Chiral Diamine Activator for High Enantiocontrol in Asymmetric Transfer Hydrogenation.

CHEMINFORM, Issue 41 2006
Koichi Mikami
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

Asymmetric Hydrosilylation of Alkenes with Alkoxyhydrosilanes Catalyzed by Chiral Bis(oxazolinyl)phenyl,Rhodium Complex.

CHEMINFORM, Issue 8 2005
Yasunori Tsuchiya
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Kinetic Studies Prove High Catalytic Activity of a Diene,Rhodium Complex in 1,4-Addition of Phenylboronic Acid to ,,,-Unsaturated Ketones

CHEMISTRY - AN ASIAN JOURNAL, Issue 5 2006
Asato Kina
Abstract In the 1,4-addition of phenylboronic acid to ,,,-unsaturated ketones, [Rh(OH)(cod)]2 has a much higher catalytic activity than [Rh(OH)(binap)]2 (cod=1,5-cyclooctadiene, binap=2,2,-bis(diphenylphosphanyl)-1,1,-binaphthyl). Kinetic studies revealed that the rate-determining transmetalation step in the catalytic cycle has a large rate constant when [Rh(OH)(cod)]2 is used. [source]

Asymmetric Ring Opening of Benzo-7-oxabicyclo[2.2.1]heptadienes with Cationic Rhodium Complexes

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2010
Angelika Preetz
Abstract The efficient design of stereochemically challenging ring systems by ring opening of heterobicyclic alkenes has become a very important reaction in the chemistry of CC and CX bond formation. By using the hitherto applied in situ technique for the generation of the ,2 -bridged, dimeric neutral rhodium complexes, however, the catalytically active species and its concentration remained unidentified. Furthermore, the reaction temperature is at least 80,°C. The application of cationic rhodium(I) solvate complexes (that no longer contain blocking diolefins) shows that a much greater activity and enantioselectivity for the synthesis of 1,2-dihydro-1-naphthols can be reached than was described so far, even at ambient temperature. NMR spectroscopy and X-ray analysis show that a product inhibition during the ring opening reaction takes place that is independent of the nucleophile. [source]

Enantioselective Hydrogenation of ,-Dehydroamino Acid Esters Catalyzed by Rhodium Complexes with Chiral Bisaminophosphine Ligands

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7 2010
Xianfeng Sun
Abstract A highly efficient strategy for the synthesis of a series of chiral bisaminophosphine ligands was well established with several remarkable features. The synthetic utility of these ligands was explored for rhodium-catalyzed asymmetric hydrogenations of ,-dehydroamino acid esters. Up to 98% ee values were achieved for the enantioselective synthesis of aminocarboxylic acids and their derivatives, which are very important chiral building blocks for the synthesis of a variety of natural products and biologically active molecules. [source]

Micellar Effects in Olefin Hydroformylation Catalysed by Neutral, Calix[4]arene-Diphosphite Rhodium Complexes

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2009
Laure Monnereau
Abstract The combination of calixarene-derived surfactants and neutral rhodium complexes containing a hemispherical "1,3-calix-diphosphite" ligand led to efficient catalysts for the hydroformylation of octene and other olefins in water. While the surfactants allowed the formation of micelles that dissolve both the catalyst and the alkene, thereby resulting in high olefin:rhodium ratios, the diphosphite provided a tight envelope about the catalytic centre able to drive the reaction towards the linear aldehydes. Best results in the hydroformylation of 1-octene were obtained when using [tetra(p -sulfonato)]-(tetra- n -butoxy)-calix[4]arene as surfactant. With this additive remarkable linear to branched aldehyde ratios of up to 62 were obtained, the corresponding activities being higher than those observed when operating in an organic solvent [turnover frequencies (TOFs) up to 630 mol(converted 1-octene), mol(Rh),1,h,1]. [source]

Asymmetric Cyclopropanation of Alkenes with Dimethyl Diazomalonate Catalyzed by Chiral Diene,Rhodium Complexes,

ANGEWANDTE CHEMIE, Issue 40 2010
Dr. Takahiro Nishimura
Mit Dreizahn zum Dreiring: Ein Rhodiumkomplex mit einem chiralen dreizähnigen Dienliganden (1; siehe Schema) erwies sich als Katalysator der intermolekularen asymmetrischen Cyclopropanierung von Alkenen mit Dimethyldiazomalonat unter Bildung von 1,1-Cyclopropandiestern in guten Ausbeuten und mit hohen Enantioselektivitäten. [source]

Titelbild: Sensitive and Selective Chromogenic Sensing of Carbon Monoxide by Using Binuclear Rhodium Complexes (Angew. Chem.

ANGEWANDTE CHEMIE, Issue 29 2010
29/2010)
Wie in einer Collage von Max Ernst kann die Kombination einer bereits bekannten molekularen Einheit (ein zweikerniger Rhodiumkomplex) mit geeigneten Brückenliganden eine neue Rolle ergeben , hier als chromogene Chemosensoren. R. Martínez-Máñez et,al. beschreiben in ihrer Zuschrift auf S.,5054,ff., wie diese Komplexe durch ihre Farbänderung als Kohlenmonoxidsensoren wirken können. [source]

Sensitive and Selective Chromogenic Sensing of Carbon Monoxide by Using Binuclear Rhodium Complexes,

ANGEWANDTE CHEMIE, Issue 29 2010
Julio Esteban Dr.
CO-Fänger: Kohlenmonoxid kann mit dem zweikernigen Rhodiumkomplex cis -[Rh2(C6H4PPh2)2(O2CCH3)2](HO2CCH3)2 selektiv und empfindlich nachgewiesen werden. Der Komplex, der zwei cyclometallierte Phosphanliganden enthält, koordiniert CO axial und ändert dabei seine Farbe von Violett nach Orangegelb (siehe Bild). [source]

ChemInform Abstract: Stereoselective exo-Addition to Norbornenes of Acetic Acid Generated from Vinyl Acetate in the Presence of Rhodium Complexes.

CHEMINFORM, Issue 29 2010
R. I. Khusnutdinov
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

ChemInform Abstract: Asymmetric Hydrogenation Using Wilkinson-Type Rhodium Complexes Immobilized onto Mesoporous Silica.

CHEMINFORM, Issue 9 2010
Reine Sayah
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Corrigendum: Asymmetric Transfer Hydrogenation of Ketones Catalyzed by Amino Acid Derived Rhodium Complexes: On the Origin of Enantioselectivity and Enantioswitchability

CHEMISTRY - A EUROPEAN JOURNAL, Issue 35 2010
Katrin Ahlford
No abstract is available for this article. [source]

Novel Contributions to the Mechanism of the Enantioselective Hydrogenation of Dimethyl Itaconate with Rhodium Complexes

CHEMISTRY - A EUROPEAN JOURNAL, Issue 15 2008
Thomas Schmidt
Easy transformation of itaconic acid and its derivatives, such as dimethyl itaconate, into pharmaceutically interesting chiral methyl succinates by enantioselective hydrogenation is described. The X-ray structure of the major catalyst,substrate complex, [Rh((S,S)-dipamp)(dimethyl itaconate)]BF4, of the reaction is shown. [source]

Trinuclear Rhodium Complexes and Their Relevance for Asymmetric Hydrogenation

CHEMISTRY - AN ASIAN JOURNAL, Issue 11 2008
Angelika Preetz
Abstract Various trinuclear rhodium complexes of the type [Rh3(PP)3(,3 -OH)x(,3 -OMe)2,x]BF4 (where PP=Me-DuPhos, dipamp, dppp, dppe; different ligands and , -bridging anions) are presented, which are formed upon addition of bases such as NEt3 to solvate complexes [Rh(PP)(solvent)2]BF4. They were extensively characterized by X-ray diffraction and NMR spectroscopy (103Rh, 31P, 13C, 1H). Their in,situ formation resulting from basic additives (NEt3) or basic prochiral olefins (without addition of another base) can cause deactivation of the asymmetric hydrogenation. This effect can be reversed by means of acidic additives. [source]

Structure, Electrochemistry and Hydroformylation Catalytic Activity of the Bis(pyrazolylborato)rhodium(I) Complexes [RhBp(CO)P] [P = P(NC4H4)3, PPh3, PCy3, P(C6H4OMe-4)3]

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 7 2004
Anna M. Trzeciak
Abstract Rhodium complexes of formula [RhBp(CO)P] [Bp = bis(pyrazolylborate), P = P(NC4H4)31, PPh32, PCy33, P(C6H4OMe-4)34] have been prepared by exchange of the acetylacetonate (acac,) ligand in [Rh(acac)(CO)P] complexes. The spectroscopic and electrochemical properties as well as X-ray data of [Rh(acac)(CO)P] and [RhBp(CO)P] complexes have been compared with the aim to estimate the relative donor properties of both anionic ligands (acac, and Bp,). The cyclic voltammetric results indicate that the Bp, ligand behaves as a much stronger electron donor than acac, and a value of the Lever EL ligand parameter identical to that of the pyrazolate ligand (,0.24 V vs. NHE for each coordinating arm) is proposed for the bis- and tris(pyrazolyl)borate ligands, whereas P(C6H4OMe-4)3 is also shown to have an identical EL value (0.69 V) to that of P(NC4H4)3. An improved linear relationship between the oxidation potential and the sum of the ligand EL values for square-planar RhI complexes is also obtained and adjusted values for the Lever SM and IM parameters for the RhI/RhII redox couple are given. The trans influence of phosphanes was not observed in crystals of complexes 2 and 3, in contrast to analogous acetylacetonato complexes in which the Rh,O bonds differ by ca. 0.04,0.06 Å. Complexes 1,4 are very attractive precursors for hydroformylation catalysts and yields of aldehydes of 80,87% have been obtained with all complexes without extra phosphane as co-catalyst. During the hydroformylation reaction, however, small amounts of a catalytically inactive [RhBp(CO)2] complex were formed. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]

The Immobilization of Rhodium-4-(diphenylphosphino)-2- (diphenylphosphinomethyl)-pyrrolidine (Rh-PPM) Complexes: A Systematic Study

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 12-13 2006
Benoît Pugin
Abstract A modular toolbox for the immobilization of homogeneous catalysts to various supports is described. It consists of functionalized chiral diphosphines and three different linkers based on isocyanate chemistry and it is used to attach the 4-(diphenylphosphino)-2-(diphenylphosphinomethyl)-pyrrolidine (PPM) ligand to a large variety of soluble, swellable and non-swellable solid organic polymers and to silica gels. As model reaction the hydrogenation of acetamidocinnamic acid derivatives, catalyzed with high enantioselectivity was chosen. Besides information on the usefulness of a particular type of support for synthetic applications, the experiments were also designed to address the question how parameters such as solubility, swellability, cage or pore size and solvent affect the rate and enantioselectivity of an immobilized catalyst. Rhodium complexes of ligands attached to soluble polymers and inorganic supports achieved ees up to 95,% and turnover frequencies between 700 and 1400,h,1, very close to the values of the homogeneous Rh catalyst (ee 95,%, TOF 1320,h,1). Insoluble or strongly cross-linked organic polymers led to catalysts with lower enantioselectivity and activity. PPM ligands attached to water soluble dendrimer fragments allowed hydrogenation in water solution with ees up to 94,%, albeit with much lower activity compared to reactions in methanol with the homogeneous catalyst. [source]

Bond catastrophes in rhodium complexes: experimental charge-density studies of [Rh(C7H8)(PtBu3)Cl] and [Rh(C7H8)(PCy3)Cl]

ACTA CRYSTALLOGRAPHICA SECTION B, Issue 5 2010
Hazel A. Sparkes
Rhodium complexes have potential uses in both catalysis and promoting the cleavage of C,C bonds. In order to further our understanding of these species and their potential applications, it is vital to obtain insight into the bonding within the species, particularly the Rh,C interactions, and to this end experimental charge-density studies have been undertaken on the title complexes. High-resolution single-crystal datasets to sin,,/, = 1.06,Å,1 were obtained at 100,K and analysed using Bader's `Atoms in Molecules' (AIM) approach. The results of the studies have provided unique insights into the bonding involving rhodium and highlight the importance of undertaking such investigations for transition metal compounds. [source]

ChemInform Abstract: Enantioselective Isomerization of Allylic Alcohols Catalyzed by a Rhodium/Phosphaferrocene Complex.

CHEMINFORM, Issue 3 2001
Ken Tanaka
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Rhodium-Catalyzed Asymmetric Nitroallylation of Arylmetallics with Cyclic Nitroallyl Acetates and Applications in Organic Synthesis

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 18 2006
Lin Dong
Abstract Highly enantioselective rhodium-catalyzed nitroallylations of arylboronic acids and arylzinc chlorides with cyclic nitroallyl acetates are described. Catalyst screening indicated that the rhodium complex of [Rh(OH)(COD)]2 and optically pure binap is the optimal catalyst for the nitroallylation of arylboronic acids with 2-nitrocyclohex-2-enyl esters, providing good yields and high enantioselectivities of up to 99,% ee. The rhodium complex prepared from Rh(acac)(C2H4)2 and (R)-binap efficiently catalyzed the nitroallylation of arylzinc chlorides with 2-nitrocyclohex-2-enyl acetate at 0 °C in high yields of up to 93,% and with high enantioselectivities of up to 96,% ee. A number of synthetically useful intermediates with high optical purity were prepared with this reaction as starting point: concise total syntheses of optically pure (+)-,-lycorane in 53,% overall yield and of (+)-,-lycorane in 52,% overall yield were achieved by commencing with the asymmetric nitroallylation of 3,4-methylenedioxyphenylzinc chloride with 2-nitrocyclohex-2-enyl acetate. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source]

Synthesis of (E)-3-Alkylidene-1-pyrrolines by the Rhodium- Catalyzed Cyclization of Terminal Alkynes with Homopropargylic Amines

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 14-15 2009
Yoshiya Fukumoto
Abstract The cyclization of terminal alkynes with homopropargylic amines in the presence of a rhodium complex as catalyst leads to the formation of (E)-3-alkylidene-1-pyrrolines. The reaction tolerates a wide range of functional groups on the terminal alkynes. The formation of a vinylidene-rhodium complex, followed by the intermolecular nucleophilic attack of a homopropargylic amine nitrogen on the ,-carbon atom of the vinylidene-rhodium complex, is proposed as a key step in the catalytic reaction. [source]

Highly Regioselective and Rapid Hydroformylation of Alkyl Acrylates Catalyzed by a Rhodium Complex with a Tetraphosphorus Ligand

Asymmetric 1,4-Addition of Organoboron Reagents to Quinone Monoketals Catalyzed by a Chiral Diene/Rhodium Complex: A New Synthetic Route to Enantioenriched 2-Aryltetralones

Synthesis and polymerization of (E)- p -[(p -methoxyphenyl)-2-ethenyl]phenylacetylene with Ziegler,Natta, rhodium, and palladium complexes

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 24 2005
J. Gonzalo Rodríguez
Abstract The synthesis and polymerization of (E)- p -[(p -methoxyphenyl)-2-ethenyl]phenylacetylene was carried out with a homogeneous vanadium acetylacetonate/aluminum triethyl catalyst system, a bis(rhodium chloride cycloocta-1,5-diene) complex, and a palladium/trimethylsilyl complex. In all cases, the main fraction was a polymer with a stereoregular structure. The polymerization with the vanadium catalyst gave a polymer fraction in a low yield. The polymerization of (E)- p -[(p -methoxyphenyl)-2-ethenyl]phenylacetylene with the soluble rhodium complex gave a polymer in a high yield. The soluble palladium/chlorotrimethylsilane complex gave a polymer in a good yield. On the basis of the spectroscopic data, the poly{(E)- p -[(p -methoxyphenyl)-2-ethenyl]phenylacetylene)} obtained, in all cases, showed a cis,transoidal stereoregular structure. The molecular mass of poly{(E)- p -[(p -methoxyphenyl)-2-ethenyl]phenylacetylene)} was determined by the matrix-assisted laser desorption/ionization time-of-flight technique. The kinetics of the reaction were analyzed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6438,6444, 2005 [source]

Combinations of Acidic and Basic Monodentate Binaphtholic Phosphites as Supramolecular Bidentate Ligands for Enantioselective Rh-Catalyzed Hydrogenations

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 15 2009
Luca Pignataro
Abstract A small library of chiral BINOL-derived monodentate phosphites containing either a carboxylic acid (-COOH, A1,A3) or a tertiary amine (-NMe2, B1,B4) was synthesized. The ligand combinations were screened in the enantioselective rhodium-catalyzed hydrogenation of methyl 2-acetamidoacrylate. The heterocombinations of the amine-derived phosphite (R)- B2 and of a carboxylic-phosphite [(R)- A1, (R)- A2, (R)- A3] displayed a slightly higher level of enantioselectivity compared to the corresponding homocombinations [up to 90,% ee using (R)- A1/(R)- B2]. The nature and extent of the interaction between the acidic and basic ligands in the rhodium complexes were studied by IR and 31P-NMR spectroscopy. The formation of an intramolecular salt in the Rh-heterocomplex, between the carboxylic acid and the tertiary amine, was suggested by the IR spectra. The selective formation of the Rh-heterocomplex was quantitatively assessed by 31P-NMR spectroscopy, using a modified acidic ligand (R)- A1-Me. In this way, a moderate (ca. 70:30) heterocomplex/homocomplexes ratio was determined.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]