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Rhodium
Kinds of Rhodium Terms modified by Rhodium Selected AbstractsCytotoxic Rhodium(III) Polypyridyl Complexes Containing the Tris(pyrazolyl)methane Coligand: Synthesis, DNA Binding Properties and Structure,Activity RelationshipsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 25 2009Ruth Bieda Abstract The RhIII complexes of the type [RhCl(pp)(tpm)]2+ [pp = bpy, bpm, phen, tap, dpq, dppz] 4,9 have been prepared by stepwise treatment of RhCl3·3H2O or mer,cis -[RhCl3(DMSO-,S)2(DMSO-,O)] with the appropriate polypyridyl ligand (pp) followed by the tripodal ligand tris(pyrazolyl)methane (tpm). Intermediates of the type [RhCl3(CH3OH)(pp)] 1,3 with pp = bpy, phen, dpq were also characterized but exhibit either low (3) or no (1, 2) cytotoxicity. X-ray structural analyses of [RhCl(bpy)(tpm)][PF6]24 and [RhCl(phen)(tpm)][PF6]26 were performed, and the interaction of complexes 4,9 with DNA was investigated by CD and UV/Vis spectroscopy and by gel electrophoresis. CD and viscosity studies confirm strong intercalation of dppz complex 9 into DNA. Complexes 8 and particularly 9 (IC50 = 0.43, 0.37 ,M) are potent cytotoxic agents towards the human cancer cell lines MCF-7 and HT-29, whereas respectively little (complex 6) or no activity (complexes 4, 5, 7) is observed for the other members of the series. Our findings indicate that the cytotoxicity is dependent on the hydrophobicity of both the polypyridyl and the facial coligand in these and other half-sandwich RhIII complexes. Irradiation of bpy compound 4 in the presence of plasmid pBR322 for 30 min at 311 nm at a molar ratio of r = 0.1 leads to total conversion of the supercoiled form into the nicked version. Although dppz complex 9 also functions as a photonuclease under these conditions, the degree of cleavage is much lower. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Chiral Diphosphite-Modified Rhodium(0) Nanoparticles: Catalyst Reservoir for Styrene HydroformylationEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 22 2008M. Rosa Axet Abstract The organometallic synthesis of rhodium nanoparticles stabilized with diphosphite ligands is described. These nanoparticles were investigated as catalysts in the styrene hydroformylation reaction, and their activity and selectivity were compared with those of similar molecular complexes. NMR spectroscopic studies performed during the course of the catalytic reaction showed that the synthesized nanoparticles are not stable and produce molecular species. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Rhodium(II)-Catalyzed Inter- and Intramolecular Cyclopropanations with Diazo Compounds and Phenyliodonium Ylides: Synthesis and Chiral AnalysisHELVETICA CHIMICA ACTA, Issue 2 2005Ashraf Ghanem Different classes of cyclopropanes derived from Meldrum's acid (=2,2-dimethyl-1,3-dioxane-4,6-dione; 4), dimethyl malonate (5), 2-diazo-3-(silyloxy)but-3-enoate 16, 2-diazo-3,3,3-trifluoropropanoate 18, diazo(triethylsilyl)acetate 24a, and diazo(dimethylphenylsilyl)acetate 24b were prepared via dirhodium(II)-catalyzed intermolecular cyclopropanation of a set of olefins 3 (Schemes,1 and 4,6). The reactions proceeded with either diazo-free phenyliodonium ylides or diazo compounds affording the desired cyclopropane derivatives in either racemic or enantiomer-enriched forms. The intramolecular cyclopropanation of allyl diazo(triethylsilyl)acetates 28, 30, and 33 were carried out in the presence of the chiral dirhodium(II) catalyst [Rh2{(S)-nttl)4}] (9) in toluene to afford the corresponding cyclopropane derivatives 29, 31 and 34 with up to 37% ee (Scheme,7). An efficient enantioselective chiral separation method based on enantioselective GC and HPLC was developed. The method provides information about the chemical yields of the cyclopropane derivatives, enantioselectivity, substrate specifity, and catalytic activity of the chiral catalysts used in the inter- and intramolecular cyclopropanation reactions and avoids time-consuming workup procedures. [source] A Study of the Stereochemical Course of , -Oxygen Elimination with a Rhodium(I) ComplexHELVETICA CHIMICA ACTA, Issue 12 2002Masahiro Murakami The stereochemical course of , -oxygen elimination of an organorhodium(I) complex was investigated through the Rh-catalyzed addition of phenylboronic acid to a chiral propargyl acetate to produce an allene. The degree of chirality transfer suggests that the , -oxygen elimination takes place in both syn and anti modes. [source] 2,2,-Bis[bis(3,5-di- tert -butyl-4-methoxyphenyl)phosphino]-6,6,-dimethoxy-1,1,-biphenyl in Intramolecular Rhodium(I)-Catalyzed Asymmetric Pauson,Khand-Type ReactionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2010Dong Eun Kim Abstract A cationic rhodium(I)/2,2,-bis[bis(3,5-di- tert -butyl-4-methoxyphenyl)phosphino]-6,6,-dimethoxy-1,1,-biphenyl (DTBM-MeO-BIPHEP) catalyst was highly efficient for the asymmetric catalytic Pauson,Khand reaction, especially for those substrates containing aryl group-substituted alkynes. The formation of the products that were derived from a ,-hydride eliminated intermediate 5 was completely suppressed over a wide range of substrates. This reaction was a serious process competing reaction with the migratory CO insertion that led to the Pauson,Khand reaction product and often substantially ruined the chemical yield of the Pauson,Khand reaction. The advantages of this system were clearly demonstrated for previously troublesome substrates, N -tosyl- (1b) and malonate-tethered 1,6-enynes (1c), that exhibited a higher enantioselectivity without a loss in the chemical yields. The obvious beneficial effects were attributed to the synergic effect of various factors, such as the electron density of the phosphorus of the ligand, the dihedral angles of the atropisomeric ligand, and the substitution on the phosphine aryl rings which play a crucial role in the stereochemical outcome of Rh-catalyzed Pauson,Khand reaction. [source] One Step Synthesis of Chiral Olefins via Asymmetric Diamination and their Applications as Ligands for Rhodium(I)-Catalyzed 1,4-AdditionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2010Xichao Hu Abstract A variety of acyclic chiral dienes were synthesized in a single step via palladium(0)-catalyzed asymmetric allylic and homoallylic CH diamination of terminal olefins. The applications of such simple dienes as steering ligands for rhodium(I)-catalyzed asymmetric 1,4-additions afforded the corresponding adducts in excellent yields and up to 85% ee. [source] Diastereoselective Hydrogenation of Substituted Quinolines to Enantiomerically Pure DecahydroquinolinesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 2-3 2010Maja Heitbaum Abstract The stereoselective hydrogenation of auxiliary-substituted quinolines was used to build up saturated and partially saturated heterocycles. In a first step, the formation and diastereoselective hydrogenation of 2-oxazolidinone-substituted quinolines to 5,6,7,8-tetrahydroquinolines is reported. In this unprecedented process, stereocenters on the carbocyclic quinoline ring were formed with a dr of up to 89:11. Platinum oxide as a catalyst and trifluoroacetic acid as a solvent were found to be optimal for high levels of chemo- and stereoselectivity in this step. In a second hydrogenation step, the completely saturated decahydroquinolines with 4 newly formed stereocenters were obtained with enantioselectivities of up to 99%. Rhodium on carbon as a catalyst and acetic acid as a solvent gave the best results for this hydrogenation and allowed a traceless cleavage of the chiral auxiliary. Thus, this new method allows an efficient stereoselective synthesis of valuable 5,6,7,8-tetrahydro- and decahydroquinoline products. [source] Rhodium- and Palladium-Catalyzed Hydroarylation of Propargylic Amines with Arylboronic AcidsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 2-3 2010Antonio Arcadi Abstract The hydroarylation of 3-arylprop-2-yn-1-amine derivatives with arylboronic acids has been studied in the presence of rhodium or palladium catalysts. By using a rhodium-based catalytic system, ,,,-diarylallylamines were isolated in good yields. By contrast, the formation of the regiosomeric ,,,-diarylallylamines was achieved by means of a palladium catalyst in the presence of acetic acid. The complementary regioselectivity displayed by these two processes is a consequence of different catalytic cycles, involving respectively carborhodation or hydropalladation of the coordinated alkyne as key steps. Calculated charge distributions in the ,-complexes are in accord with the results obtained. [source] DiPAMP's Big Brother "i- Pr-SMS-Phos" Exhibits Exceptional Features Enhancing Rhodium(I)-Catalyzed Hydrogenation of OlefinsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 17 2009Michel Stephan Abstract Switching Knowles DiPAMP's {DiPAMP=1,2-bis[(o -anisyl)(phenyl)phosphino]- ethane} MeO groups with i- PrO ones led to the i- Pr-SMS-Phos {i- Pr-SMS-Phos=1,2-bis[(o -isoprop- oxyphenyl)(phenyl)phosphino]ethane} ligand which displayed a boosted catalyst activity coupled with an enhanced enantioselectivity in the rhodium(I)-catalyzed hydrogenation of a wide-range of representative olefinic substrates (dehydro-,-amido acids, itaconates, acrylates, enamides, enol acetates, ,,,-diarylethylenes, etc). The rhodium(I)-(i- Pr-SMS-Phos) catalytic profile was investigated revealing its structural attributes and robustness, and in contrast to the usual trend, 31P,NMR analysis revealed that its methyl (Z)-,-acetamidocinnamate (MAC) adduct consisted of a reversed diastereomeric ratio of 1.4:1 in favour of the most reactive diastereomer. [source] Novel Enantioselective Sequentially Rhodium(I)/BINAP- Catalyzed Cycloisomerization,Hydrogenation,Isomerization, Acetalization (CIHIA)ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 17 2009Nadine Körber Abstract Linear, easily accessible alkyl and (hetero)aryl-substituted alkynyl allyl alcohols are readily and enantioselectively transformed into 2,7-dioxabicyclo[3.2.1]octanes by a sequential rhodium-catalyzed process. Based on the initial cycloisomerization, the in situ generated rhodium(I)-BINAP complex enables a subsequent reduction with hydrogen and the transformation into bicyclic frameworks. [source] Synthesis of (E)-3-Alkylidene-1-pyrrolines by the Rhodium- Catalyzed Cyclization of Terminal Alkynes with Homopropargylic AminesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 14-15 2009Yoshiya 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] Effect of Ring Methylation on the Photophysical, Photochemical and Photobiological Properties of cis -Dichlorobis(1,10-Phenanthroline)Rhodium(III)Chloride,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 1 2006Devanesan Loganathan ABSTRACT Methylated analogues of cis -dichlorobis(1,10-phenanthroline)-rhodium(III)chloride (BISPHEN) have been prepared in order to increase the hydrophobicity of the parent compound, and thus create octahedral rhodium (III) complexes suitable for use as anticancer and antiviral agents that can be photo-activated. The parent complex has been shown in earlier work to be unable to cross through cell membranes. Octamethylation, as in the case of cis -dichlorobis(3,4,7,8-tetramethyl-1,10-phenanthroline)rhodium(III)chloride (OCTBP), provides enough hydrophobicity to be taken up by KB tumor cells. It also provides a higher level of ground-state association with double-stranded DNA and increases the quantum efficiency of photoaquation by greater than 10-fold, relative to BISPHEN. OCTBP forms covalent bonds to deoxyguanosine when irradiated with the nucleoside, as has been seen with the parent complex. Irradiation of OCTBP in the presence of the KB or M109 tumor cell lines using narrow-band UVB (,= 311 nm) irradiation initiates a considerable amount of phototoxicity. There is evidence that OCTBP acts as a prodrug (i.e. after passing through the cell membrane the metal complex is photolyzed to cis -chloro aquo OCTBP, which may be the active phototoxic agent). OCTBP and the tetramethyl analogue cis -dichlorobis(4,7-dimethyl-1,10-phenanthroline)rhodium(III)chloride (47TMBP) also show photoaquation upon excitation with visible light (, > 500 nm), and indeed, some phototoxicity of KB cells is observed at these wavelengths as well. This is attributed to direct population of photoactive triplet-excited states. These results, together with our earlier studies of cis -dichloro[dipyrido(3,2-a: 2,,3,-c)phenazine (1,10-phenanthroline)rhodium(III)chloride (DPPZPHEN) demonstrate that such octahedral rhodium complexes are viable "photo-cisplatin" reagents. [source] Rhodium(II)-Catalyzed One-Pot Four-Component Synthesis of Functionalized Polyether Macrocycles at High Concentration,ANGEWANDTE CHEMIE, Issue 40 2010Dr. Walid Zeghida Vollkommen unerwartet wurde die Rhodium(II)-katalysierte templatfreie Makrocyclisierung von vier Einzelkomponenten in einem Reaktionsgefäß effizienter, wenn die Konzentration erhöht wurde. Daher kondensierten ,-Diazo-,-ketoester mit 1,4-Dioxan, THF oder Tetrahydropyran als Lösungsmittel zu 16- bis 18-gliedrigen Polyethermakrocyclen in bis zu 75,% Ausbeute (siehe Schema; R=Me, Et, PhCH2CH2, Allyl, PhCHCH2). [source] Nanotexture Switching of Single-Layer Hexagonal Boron Nitride on Rhodium by Intercalation of Hydrogen Atoms,ANGEWANDTE CHEMIE, Issue 35 2010Thomas Brugger Dr. Mit H eben, ohne H gewellt: Bei der Behandlung einer Monoschicht aus hexagonalem Bornitrid auf Rhodium mit Wasserstoffatomen verschwindet die h -BN-Oberflächenwellung (siehe Bild: blauer Bereich gewellt, oranger Bereich flach). Diese Veränderung der Oberflächentextur, eine Folge der Interkalation von Wasserstoffatomen, lässt sich rückgängig machen, indem die Wasserstoffatome durch Erhitzen auf etwa 600,K entfernt werden. [source] Rhodium(I)-Catalyzed Intramolecular [5+2],Cycloaddition Reactions of Alkynes and Allenylcyclopropanes: Construction of Bicyclo[5.4.0]undecatrienes and Bicyclo[5.5.0]dodecatrienes,ANGEWANDTE CHEMIE, Issue 12 2010Fuyuhiko Inagaki Dr. Von Allenen zu Bicyclen: Bei der [{RhCl(CO)2}2]- oder [{RhCl(CO)dppp}2]-katalysierten intramolekularen [5+2]-Cycloaddition von Alkin-Allenylcyclopropanen entstehen unter milden Bedingungen die Bicyclo[5.4.0]undecatrien- oder die größeren Bicyclo[5.5.0]dodecatrien-Gerüste (dppp=1,3-Bis(diphenylphosphanyl)propan). [source] Shuttling P3 from Niobium to Rhodium: The Synthesis and Use of Ph3SnP3(C6H8) as a P3, Synthon,ANGEWANDTE CHEMIE, Issue 9 2010Brandi Anatomie eines P3, -Synthons: Das Ph3SnP3(C6H8)-Molekül (siehe Bild; Sn,rot, P,orange) wurde durch Triphosphortransfer von einem Niob-Komplex synthetisiert und dient als nützliches P3, -Reservoir. Die Behandlung von Ph3SnP3(C6H8) mit dem Wilkinson-Katalysator, [ClRh(PPh3)3], führte unter Abspaltung von Ph3SnCl und 1,3-Cyclohexadien zum neuen Cyclo-P3 -Komplex [(,3 -P3)Rh(PPh3)3]. [source] Catalytic Oxyamidation of Indoles,ANGEWANDTE CHEMIE, Issue 9 2010Stéphane Beaumont Dr. Zweifach variabel: Eine effiziente intermolekulare Oxyamidierung von Indolen beruht auf dem Einsatz von Rhodium(II)-katalysierten Nitren-Transfers. Durch Wechsel des Nucleophils kann die Reaktion selektiv zu den cis - oder trans -Produkten geführt werden. Auch die Regioselektivität der Addition kann gesteuert werden, indem man den Substituenten an der Indol-Doppelbindung variiert (siehe Schema). [source] Rhodium and Iridium Aminoborane Complexes: Coordination Chemistry of BN Alkene Analogues,ANGEWANDTE CHEMIE, Issue 5 2010Christina Seitlich oder frontal? Rhodium- und Iridiumkomplexe mit R2NBH2 -Liganden wurden synthetisiert und strukturell charakterisiert. Kristallographische Analysen ergaben, dass diese Liganden , ganz anders als die isoelektronischen Alkendonoren , frontal koordinieren (end-on) und ein Bis(,-boran)-Bindungsmotiv bilden (siehe Struktur). [source] Rhodium(I)-Catalyzed [4+1],Cycloaddition Reactions of ,,,-Unsaturated Imines with Terminal Alkynes for the Preparation of Pyrrole Derivatives,ANGEWANDTE CHEMIE, Issue 44 2009Akio Mizuno Rhodiumvinyliden-Intermediate charakterisieren die Titelreaktion (siehe Schema). Die Reaktion verläuft über die nucleophile Addition des Imin-Stickstoffatoms an den Rhodiumvinyliden-Komplex zu einem zwitterionischen Intermediat, das durch intramolekulare Cyclisierung zum Pyrrol weiterreagiert. coe: Cycloocten, Cy: Cyclohexyl. [source] Synthesis of Chiral Tetrasubstituted Alkenes by an Asymmetric Cascade Reaction Catalyzed Cooperatively by Cationic Rhodium(I) and Silver(I) Complexes,ANGEWANDTE CHEMIE, Issue 43 2009Daiki Hojo Magische Vier: Die Titelreaktion, die hoch enantioselektiv zu tetrasubstituierten Alkenen führt, eignet sich auch zur enantio- und diastereoselektiven Synthese von tetrasubstituierten helicalen Alkenen, die sowohl über Chiralitätszentren als auch über Helizität verfügen (siehe Schema). [source] ChemInform Abstract: Cationic Rhodium(I) Complex-Catalyzed [3 + 2] and [2 + 1] Cycloadditions of Propargyl Esters with Electron-Deficient Alkynes and Alkenes.CHEMINFORM, Issue 39 2010Yu Shibata Abstract A variety of acyloxy-substituted tertiary propargyl esters undergo the title cycloaddition reaction with acetylenedicarboxylates to give cyclopentadienetricarboxylates. [source] ChemInform Abstract: Rhodium(III)-Catalyzed Intermolecular Hydroarylation of Alkynes.CHEMINFORM, Issue 36 2010Derek J. Schipper No abstract is available for this article. [source] ChemInform Abstract: Rhodium(I)-Catalyzed Enantioselective Activation of Cyclobutanols: Formation of Cyclohexane Derivatives with Quaternary Stereogenic Centers.CHEMINFORM, Issue 29 2010Tobias Seiser 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: Rhodium(I)-Catalyzed Enantioselective Activation of Cyclobutanols: Formation of Cyclohexane Derivatives with Quaternary Stereogenic Centers.CHEMINFORM, Issue 29 2010Tobias Seiser 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: Synthesis and Reactivity of Rhodium(II) N-Triflyl Azavinyl Carbenes.CHEMINFORM, Issue 29 2010Neil Grimster 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: Modular Synthesis of the ClickFerrophos Ligand Family and Their Use in Rhodium- and Ruthenium-Catalyzed Asymmetric Hydrogenation.CHEMINFORM, Issue 9 2010Hiroshi Oki 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 Transfer Hydrogenation Catalyzed by a Novel Planar Chiral N-Heterocyclic Carbene,Rhodium(I) Complex.CHEMINFORM, Issue 35 2009Ru Jiang 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 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: Rhodium(I)-Catalyzed Cycloisomerization of 1,3-Dienes with Alkenes in a Tether.CHEMINFORM, Issue 32 2009Yoshihiro Oonishi 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 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: Rhodium(I)-Catalyzed Reductive Cyclocarbonylation of Internal Alkynes: Atom-Economic Process for Synthesis of 2-Cyclopenten-1-ones, 5-Alkylidenefuran-2(5H)-ones and Indan-1-ones.CHEMINFORM, Issue 32 2009Qiufeng Huang 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 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: Rhodium(I)-Catalyzed Cyclization Reaction of o-Alkynyl Phenols and Anilines.CHEMINFORM, Issue 30 20093-Disubstituted Benzofurans, Domino Approach to , Indoles. 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 of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] | ||||||||||||||||||||||||||||||||||