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Dive into the research topics where Richard Korswagen is active.

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Featured researches published by Richard Korswagen.


Journal of Organometallic Chemistry | 1988

Untersuchungen zur Reaktivität der MetallMetall-Dreifachbindungen in den Spezies (C5R5)2M2(CO)4 (R = H, Me; M = Cr, Mo, W) gegenüber kondensierten Dämpfen von Schwefel, Selen und Tellur

K. Endrich; Ernst Guggolz; O. Serhadle; Manfred L. Ziegler; Richard Korswagen

Abstract Condensation of chalcogenide vapours (S, Se, Te) onto a THF matrix containing the species (C 5 R 5 ) 2 M 2 (CO) 4 (MM) (R = H, CH 3 ; M = Cr, Mo, W) in a metal vapour apparatus (temperature of liquid nitrogen, 10 −4 bar) upon warming (S 10, Se 15, Te 5 (CH 3 ) 5 W 2 (CO) 4 E 3 (E = S ( 2 ), Se ( 13 )) and (C 5 (CH 3 ) 5 ) 2 W 2 (CO) 4 E 2 (Se, ( 13a ), Te ( 17 )). The species, which are primary adducts of the chalcogenides to the WW bond, could not be synthesized by the “thermic” reactions reported in the literature. The species 2 and 13 are readily converted into the chalcogenide complexes such as (C 5 (CH 3 ) 5 ) 2 Mo 2 O 2 Se ( 16 ) liberating CO. 17 was protonated to give the complex salt [(C 5 (CH 3 ) 5 ) 2 W 2 (CO) 4 (Te 2 H 2 )] 2+ [BF 4 ] 2 − ( 18 ) by HBF 4 . The compounds were characterized by elemental analysis and their spectroscopic data, X-ray diffraction studies of 13a, 16 and 18 are described.


Journal of Organometallic Chemistry | 1986

1H NMR study of the reversible cis/trans isomerization of {(μ-CH2)(μ-CO)[η5-C5H5Fe(CO)]2}

María Inés Altbach; César A. Muedas; Richard Korswagen; Manfred L. Ziegler

Abstract The cis / trans isomerization of the bridging methylene complex {(μ-CH2)(μ-CO)[η5-C5H5-Fe(CO)]2} was studied in solution by 1H NMR spectrometry, using solvents with different polarities (acetone-d6, chloroform-d1 and benzene-d6). Equilibrium constants and rate constants for the forward and reverse steps were measured between 278 and 323 k. Both reactions show first-order kinetics. A possible mechanism for the isomerization is proposed, involving the breaking of a FeFe bond in the rate-determining step.


Journal of Organometallic Chemistry | 1989

Darstellung und Charakterisierung von Eisenkomplexen, entstanden aus der Reaktion von [(C5R5)Fe(CO)2]2 (R = H, Me) mit Phosphoryliden

Celia Caballero; Jorge Chávez; Ömer Göknur; Inge Löchel; Bernhard Nuber; Heike Pfisterer; Manfred L. Ziegler; Pía Alburquerque; Liliana Eguren; Richard Korswagen

Abstract Reaction of [Cp′Fe(CO) 2 ] 2 ( 1b (Cp′ = MeC 5 H 4 ) with the phosphorus ylide Ph 3 PCH 2 yields two products. {μ-CH 2 )(μ-CO)[Cp′Fe(CO)] 2 } ( 2b ) and Cp′(CO)(PPh 3 )Fe(COCH 3 ) ( 4 ). The crystal structure analysis of 2b is reported. It is shown, that with different phosphorus ylides the reaction of [CpFe(CO) 2 ] 2 ( 1a ) (CP = C 5 H 5 ) proceeds differently depending also on the amount of n-butyllithium present. So a threefold excess of the LiX adducts (X = Cl, Br) of the ylides Ph 3 PCHR in the presence of a large excess of n-butyllithium gives metallacyclic compounds of composition Cp(CO)Fe{HRCP(C 6 H 4 )Ph 2 } (R = H ( 3a ), R = CH 3 ( 3b ), R = C 2 H 5 ( 3c )) in the case of alkylidene ylides and Cp(CO)(PPh 3 )FeCH 2 Ph ( 5 ) with the benzylidene ylide (R = C 6 H 5 ). In the presence of a large excess of n-butyllithium, a twofold excess of Ph 3 PCHPh reacts with 1a to give the compound C 32 H 23 FeO 2 P ( 6 ) characterized by spectroscopic data and an X-ray diffraction study. In 6 an η 3 -cyclopentyl ring is coordinated to the iron atom together with two CO ligands, a phenyl ring and an ylidic carbon atom. Also characterized by an X-ray diffraction study was 3c , which was found to have a metallacycle containing an iron and a phosphorous atom, the ylidic carbon and two carbon atoms from one “phenyl” ring of the PPh 3 group as ring members. Reaction of (CH 3 ) 2 PhPCH 2 ·LiI with 1a gives extremely air-sensitive monophosphonioalkyl complex {(ηCo) 2 [CpFe(CO)][CpFeL]} ( 8 ) (L = Me 3 PCH 2 ). Some mechanistic considerations on the various reaction types of 1a based on the data obtained are presented.


Zeitschrift für Naturforschung B | 1988

Über die Reaktionen von Phosphoryliden mit homodinuklearen Organometallverbindungen des Molybdän und Wolfram / On the Reaction of Phosphorylides with Homodinuclear Organometallic Compounds of Molybdenum and Tungsten

K Endrich; P Alburquerque; Richard Korswagen; Manfred L. Ziegler

We report first the complete study of the reactions of [CpMo(CO)2]2 (Mo≡Mo) (1, Cp = η5-C5H5) with salt-free phosphorus ylides Ph3P=CHR (2, Ph = C6H5; R = H (2a), CH3 (2b), C3H7 (2c), C6H5 (2d)) and with the Nal-adducts of the ylides Ph3P=CMe2 (Me = CH3), PhMe2P=CH2 and (PhO)3P=CH2. With 2, products of the type Cp(CO)2LMo-MoL(CO)2Cp (7, L = ylide) were obtained, and the salt adducts gave addition compounds of the type Cp(CO)2LMo-MoL(CO)2Cp-2NaI (12, L = ylide). These very reactive products represent novel bisphosphonioalkyl complexes, and were characterized by IR, mass and 1H NMR spectrometry. The reaction of 1 with hexaphenylcarbodiphosphorane, C(PPh3)2, leads to a novel double addition product, Cp2Mo2(CO)4[C(PPh3)2]2 (14). Some reactions of compounds 7, 12 and 14 were also studied; 7d (L = CHPh -PPh3) reacts with NaNH2 yielding ammonia and the disodium salt of the novel dianionic complex [CpMo(CO)2(CPh-PPh3)]22- (15); 7a (L = CH2-PPh3) reacts with CH3I forming CpMo(CO)3CH3 and traces of CpMo(CO)2(PPh3)I; all compounds of types 7,12 and 14 react with adsorbents (Silica-gel, Al2O3, etc.); thus chromatography is impossible, even under strict protection from air and humidity. A study of the processes occurring during chromatography under various conditions and the resulting products are also reported and discussed. [CpW(CO)3]2 (18) reacts with 2a forming also a bisphosphonioalkyl complex [CpW(CO)2L]2(L = CH2=PPh3); in this case, the ylide substitutes two carbonyl groups in 18. The compounds [Cp*M(CO)2]2 (M≡M) (Cp* = C5Me5 ; M = Cr, W) apparently do not react with phosphorous ylides; the corresponding Mo compound, [Cp*Mo(CO)2]2 , does react, but only the new mono-nuclear complex Cp*Mo(CO)2(PPh3)Cl (22) could be isolated.


Zeitschrift für Naturforschung B | 1988

Über die Reaktivität von [(CH3)2N]6W2 (W≡W) gegenüber CS2/S8 und CS2/Se8. Röntgenstrukturanalyse von [(CH3)2NCS2]2W(S)(S2) / Reactivity of [(CH3)2N]6W2 (W≡W) Towards CS2/S8 and CS2/Se8. X-Ray Structure Analysis of [(CH3)2NCS2]2W(S)(S2)

Manfred L. Ziegler; Klaus Blechschmitt; Harald Bock; Ernst Guggolz; Richard Korswagen

Abstract In this paper we report two improved preparation methods for [(CH3)2N]6W2 (W≡W) (1), one starting from WCl4 (yield 51%), and a second one starting from W2C16(THF)4 (ca. 60% yield). We have studied the reactions of 1 with different nucleophiles, among them triphenylalkylidenphosphoranes (like Ph3P=CH2 and Ph3P=CHPh·LiCl; Ph = phenyl), sulfur and CS2 . 1 reacts with S8 and CS2 in hexane to yield the two new compounds (Me2NCS2)2WS(S2) (4) and W(CS2H)(Me2NCS2)2 (5), both containing dithiocarbamato ligands formed by insertion of CS2 into the W-N bond. The two mononuclear compounds were characterized spectroscopically, in the case of 4 an X-ray diffraction structure analysis was performed. The reaction of 1 with Se and CS2 , leads to the compounds 4, (Me2NCS2)2W2S4 (6) and [(Me2N)2C]CS2 (7), which were also characterized spectroscopically. No Se-containing compounds could be isolated. 4 crystallizes monoclinically, C52h-P21/n, with a = 648.6(3), b = 1346.7(6) and c = 1745.9(7) pm, β = 91.85(3)°, V = 1524x106 pm3 , Z = 4. The structure of the seven-coordinate tungsten compound is discussed and compared to complexes with similar ligands and geometry.


Zeitschrift für Naturforschung B | 1979

Darstellung und Charakterisierung von „Nitrenkomplexen“ des Molybdän und Wolfram der Zusammensetzung [(η5-C5H5)OM]2(μ-NCOOC2H5)2 (M = Mo, W ) und [(η5-C5H5)OMo]2(μ-NCO2C2H5)(μ-O) / Synthesis and Characterization of "Nitrene Complexes" of Molybdenum and Tungsten of Composition [(η5-C5H5)OM]2(μ-NCOOC2H5)2 (M = Mo, W ) and [(η5-C5H5)OMo]2(μ-NCO2C2H5)(μ-O)

Richard Korswagen; Klaus Weidenhammer; Manfred L. Ziegler

The photolytical reactions of η5-C5H5Mo(CO)3CH3 (1) or η5-C5H5W(CO)3CH3 (2) with N3CO2C2H3 (3) in CH2Cl2 yield the “nitrene” complexes [(η5-C5H5JMoO)(μ-NCO2C2H5)2 (4), [(η5-C5H5)WO]2(μ-NCO2C2H5)2 (5) and [(η-C5H5JMoO]2(μ-NCO2H5)(μ-O) (6) together with some η5-C5H5Mo(CO)3Cl (7) and η5-C5H5W(CO)3Cl (8), proving that the solvent takes part in the reaction. Compounds 4, 5 and 6 contain bridging imido groups, arising from the capture of probably free nitrenes NCO2C2H5 by organometallic species. Evidence for the presence of free nitrenes in the reaction medium is provided by the isolation of urethane (9), tetrachlorethene (10), 7 and 8 as secondary products.


Angewandte Chemie | 1981

Novel Reactions of Phosphorus Ylides with Carbonyl(cyclopentadienyl)metal Complexes: Preparative Access to μ‐Alkylidene Complexes and Unexpected Acylations

Richard Korswagen; Reinhold Alt; Dieter Speth; Manfred L. Ziegler


Angewandte Chemie | 1982

A μ2-η2-Styryl Complex by Reaction of Cp2Mo2(CO)4 with the Wittig Reagent (C6H5)3PCH2†‡

Klaus Endrich; Richard Korswagen; Thomas Zahn; Manfred L. Ziegler


Angewandte Chemie | 1981

Neuartige Reaktionen von Phosphor-Yliden mit Carbonyl(cyclopentadienyl)metall-Komplexen: Präparativer Zugang zu μ-Alkyliden-Komplexen und unerwartete Acylierungen†

Richard Korswagen; Reinhold Alt; Dieter Speth; Manfred L. Ziegler


Angewandte Chemie | 1982

Ein μ2‐ν2‐Styryl‐Komplex durch Reaktion von Cp2Mo2(CO)4 mit dem Wittig‐Reagens (C6H5)3PCH2

Klaus Endrich; Richard Korswagen; Thomas Zahn; Manfred L. Ziegler

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Fritz Räuchle

Pontifical Catholic University of Peru

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Liliana Eguren

Pontifical Catholic University of Peru

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Mario Ceroni

Pontifical Catholic University of Peru

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B Elena Flores

Pontifical Catholic University of Peru

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Carlos A. Castro

Pontifical Catholic University of Peru

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