Homogeneous catalysts for olefin disproportionations from nitrosyl molybdenum and tungsten compounds

Zuech, Ernest A.; Hughes, William B.; Kubicek, D. H.; Kittleman, E. T.

doi:10.1021/ja00706a018

Cited by 127 publications

(39 citation statements)

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“…The reaction of dinitrosylmolybdenum complexes with chloroaluminum alkyls has been indeed the subject of several reports, as these were active catalysts in alkene metathesis, as already mentioned [14,15]. Of interest is the fact that the dinitrosyl ligands were found to be still present in these reactions, in particular when using alcohols as modifiers [40,41].…”

Section: Comentioning

confidence: 95%

“…The association of dinitrosyl molybdenum complexes/ chloroalkylaluminum reagents to produce alkene metathesis catalysts has been known for a long time, as the first paper in the field has appeared very early in the corresponding literature, when the reaction was so called "disproportionation" [14,15]. Of interest in the corresponding papers is that a comparison was made using molybdenum versus tungsten dinitrosyl complexes.…”

Section: Dinitrosyl Molybdenum Based Catalystsmentioning

confidence: 99%

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In SituGeneration of Molybdenum-Based Catalyst for Alkyne Metathesis: Further Developments and Mechanistic Insights

Lopez

Zaranek

Pawluć

et al. 2016

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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-Molybdenum-based catalysts are among the best candidates to achieve alkyne metathesis. They can be either well-defined carbynes, previously synthesized before their use, but also prepared in situ upon using stable molybdenum carbonyl complexes, or high oxidation state molybdenum salts that need a previous alkylation, both type of precursors being "activated" by hydroxyl-containing compounds such as phenols and silanols. This paper is presenting studies made on these systems, directed towards the knowledge of the reaction paths leading to the active species, and in particular to define the essential role of hydroxyl-containing co-catalyst in the formation of the active species, still ill-defined. From an analysis of the byproducts formed during the reaction, as well as of the initial products, reaction paths to access catalytic carbyne species is suggested, where the ligand environment consists of phenoxy (or siloxy) groups, typically required and identified to lead to alkyne metathesis in the case of well-defined catalysts.Résumé -Génération in situ de catalyseurs de métathèse des alcynes à base de molybdène : développements récents et approche mécanistique -Les catalyseurs à base de molybdène font partie des candidats les plus efficaces pour la métathèse des alcynes. Ceux-ci peuvent être soit des carbynes de molybdène préalablement synthétisés avant leur mise en oeuvre, mais aussi préparés in situ via l'entremise de complexes à base de molybdène carbonyles, ou encore par alkylation de sels à haut degré d'oxydation, ces deux types de précurseurs nécessitant la présence de composés hydroxylés tels que des phénols ou silanols. Cette publication a pour objet de présenter des études visant à déterminer le mode de formation des espèces catalytiques impliquées dans ces deux systèmes, et en particulier du rôle du cocatalyseur hydroxylé, encore mal défini, dans la formation des espèces actives. De l'analyse des produits secondaires obtenus en cours de réaction, ainsi que des produits initiaux, on propose des voies de formation des espèces catalytiques de type carbyne, dont la particularité serait de disposer d'un environnement de ligands de type phénoxy (ou silyloxy), typiquement requis et identifiés pour favoriser le cycle catalytique relatif à la métathèse des alcynes sur des complexes carbynes bien définis.

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Section: Comentioning

confidence: 95%

Section: Dinitrosyl Molybdenum Based Catalystsmentioning

confidence: 99%

In SituGeneration of Molybdenum-Based Catalyst for Alkyne Metathesis: Further Developments and Mechanistic Insights

Lopez

Zaranek

Pawluć

et al. 2016

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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“…Later, various catalysts based on tungsten combined to an alkylating agent were described such as WCl 6 /EtOH/EtAlCl 2 , WCl 6 /SnBu 4 , or (ArO) 4 WCl 2 /SnMe 4 and are active for the metathesis of internal oleins such as cis-pent-2-ene [13][14][15]. Systems based on the combination of nitrosyl complexes of molybdenum or tungsten with alkylaluminum species were developed for the metathesis of terminal oleins (pent-1-ene, oct-1-ene) [16][17][18][19]. In parallel, many academic researchers tried to synthesize metal alkylidene species which should be active for olein metathesis as proposed by Chauvin.…”

Section: Group VI Complexes Used In Homogeneous Catalysismentioning

confidence: 99%

Olefin Metathesis by Group VI (Mo, W) Metal Compounds

Lefèbvre¹,

Bouhoute²,

Szeto³

et al. 2018

Alkenes

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Olein metathesis is an important reaction not only in petroleum chemistry but also in ine chemistry. Professors Grubbs, Schrock, and Chauvin obtained the Nobel Prize in 2005 for the development of this reaction (determination of the mechanism and synthesis of homogeneous catalysts). This reaction can be described as the redistribution of carbon chains of oleins via a breaking of their C═C double bonds. It is catalyzed by metal carbenes and the catalytic cycle passes through a metallacyclobutane. The purpose of this chapter is to give an overview of catalysts based on tungsten or molybdenum active for this reaction. Numerous tungsten and molybdenum organometallic complexes displaying a carbene functionality were synthesized. Some of them are highly active in olein metathesis. Industrially, tungsten oxide on silica is used as a precursor of the propene production by olein metathesis of but-2-ene and ethylene. However, the active sites are not well known but they can be modeled by grafting, via surface organometallic chemistry, perhydrocarbyl complexes of molybdenum or tungsten on oxide surfaces. After a review of the complexes used in homogeneous catalysis, a review of the industrial catalysts and their models will be given.

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“…This reaction was discovered in the late 1950s by Herbert S. Eleuterio, at DuPont's petrochemicals department, in Delaware, USA, on investigations with propene over heterogeneous molybdenum catalysts and initiated widespread studies of this field in industry as well as in academic institutions [5]. Hence, shortly thereafter a number of very active homogeneous catalysts have been discovered and described [6][7][8][9]. The large majority of these catalysts contained molybdenum or tungsten centers in high oxidation states.…”

Section: Introductionmentioning

confidence: 99%

“…The large majority of these catalysts contained molybdenum or tungsten centers in high oxidation states. Low-valent nitrosyl derivatives of molybdenum have also been successfully used [9]. phenomenological activity than the original Grubbs complexes, even approaching the activities of the very active molybdenum catalysts, [Mo(=CHR)(OR) 2 (NAr)] [29] developed by Schrock.…”

Section: Introductionmentioning

confidence: 99%

Dinitrosyl rhenium complexes for ring-opening metathesis polymerization (ROMP)

Frech

Blacque

Berke

2006

Pure and Applied Chemistry

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The treatment of benzene solutions of the cations [Re(NO) 2 (PR 3 ) 2 ][BAr F 4 ] (R = Cy and R = i Pr; [BAr F 4 ] = tetrakis{3,5-bis(trifluoromethyl)phenyl}borate) with phenyldiazomethane afforded the moderately stable cationic rhenium(I) benzylidene dinitrosyl bis(trialkyl) phosphine complexes as [BAr F 4 ] -salts in good yields. The cationic rhenium dinitrosyl bisphosphine complexes catalyze the ring-opening metathesis polymerization (ROMP) of highly strained nonfunctionalized cyclic olefins to give polymers with relatively high polydispersity indices, high molecular weights, and Z configurations of the double bonds in the polymer chain backbones of over 80 %. The benzylidene derivatives are almost inactive in ROMP catalysis with norbornene and in olefin metathesis. NMR experiments gave first hints for the initial formation of carbene complexes when [Re(NO) 2 (PR 3 ) 2 ][BAr F 4 ] was treated with norbornene. The carbene formation is initiated by an unique reaction sequence where the cleavage of the strained olefinic bond starts with phosphine migration forming a cyclic ylid carbene complex. The [2+2] addition of a norbornene molecule to the Re=C bond leads to the rhenacyclobutane complex, which is expected to be converted into an iminate complex by attack of the ylid function onto one of the N NO atoms followed by Wittig-type phosphine oxide elimination. The formation of phosphine oxide was confirmed by NMR spectroscopy. This species is thought to drive the ROMP metathesis with alternating rhenacyclobutane formations and cycloreversions. The proposed mechanism is supported by density functional theory (DFT) calculations.

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Homogeneous catalysts for olefin disproportionations from nitrosyl molybdenum and tungsten compounds

Abstract: All utilized kinetic procedures have already been described in ref 2.

Cited by 127 publications

References 0 publications

In SituGeneration of Molybdenum-Based Catalyst for Alkyne Metathesis: Further Developments and Mechanistic Insights

In SituGeneration of Molybdenum-Based Catalyst for Alkyne Metathesis: Further Developments and Mechanistic Insights

Olefin Metathesis by Group VI (Mo, W) Metal Compounds

Dinitrosyl rhenium complexes for ring-opening metathesis polymerization (ROMP)

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