Multiple metal-carbon bonds. 43. Well-characterized, highly active, Lewis acid free olefin metathesis catalysts

1986 ◽  
Vol 108 (10) ◽  
pp. 2771-2773 ◽  
Author(s):  
Colin J. Schaverien ◽  
John C. Dewan ◽  
Richard R. Schrock
Keyword(s):  
Lewis Acid ◽  
Olefin Metathesis ◽  
Highly Active ◽  
Carbon Bonds ◽  
Metathesis Catalysts

Merrifield resin-assisted routes to second-generation catalysts for olefin metathesis

2018 ◽  
Vol 8 (6) ◽  
pp. 1535-1544 ◽  
Author(s):  
Daniel L. Nascimento ◽  
Emma C. Davy ◽  
Deryn E. Fogg
Keyword(s):  
Olefin Metathesis ◽  
Second Generation ◽  
Highly Active ◽  
Merrifield Resin ◽  
Metathesis Catalysts

Phosphine-scavenging Merrifield resins can significantly facilitate the synthesis of highly active Ru metathesis catalysts, including the second-generation Grubbs, Hoveyda, and indenylidene catalysts (GII, HII, InII).

Highly Active, Stable, and Selective Well-Defined Silica Supported Mo Imido Olefin Metathesis Catalysts

2007 ◽  
Vol 129 (5) ◽  
pp. 1044-1045 ◽  
Author(s):  
Frédéric Blanc ◽  
Jean Thivolle-Cazat ◽  
Jean-Marie Basset ◽  
Christophe Copéret ◽  
Adam S. Hock ◽  
...  
Keyword(s):  
Olefin Metathesis ◽  
Highly Active ◽  
Metathesis Catalysts

Avoiding rhenium loss in non-hydrolytic synthesis of highly active Re–Si–Al olefin metathesis catalysts

2015 ◽  
Vol 58 ◽  
pp. 183-186 ◽  
Author(s):  
Karim Bouchmella ◽  
Mariana Stoyanova ◽  
Uwe Rodemerck ◽  
Damien P. Debecker ◽  
P. Hubert Mutin
Keyword(s):  
Olefin Metathesis ◽  
Highly Active ◽  
Metathesis Catalysts

Multiple metal-carbon bonds. 19. How niobium and tantalum complexes of the type M(CHCMe3)(PR3)2Cl3 can be modified to give olefin metathesis catalysts

1981 ◽  
Vol 103 (6) ◽  
pp. 1440-1447 ◽  
Author(s):  
S. M. Rocklage ◽  
J. D. Fellmann ◽  
G. A. Rupprecht ◽  
L. W. Messerle ◽  
R. R. Schrock
Keyword(s):  
Olefin Metathesis ◽  
Carbon Bonds ◽  
Metathesis Catalysts

scholarly journals Olefin-surface interactions modulate the activity of silica-supported Mo-based olefin metathesis catalysts

2021 ◽  
Author(s):  
Zachariah Berkson ◽  
Moritz Bernhardt ◽  
Simon Schlapansky ◽  
Mathis Benedikter ◽  
Michael Buchmeiser ◽  
...  
Keyword(s):  
Chain Length ◽  
Olefin Metathesis ◽  
Active Sites ◽  
Reaction Rates ◽  
Catalytic Performance ◽  
Strong Activity ◽  
Oh Groups ◽  
Highly Active ◽  
Metathesis Catalysts ◽  
Internal Olefin

Molecularly defined and classical heterogenous Mo-based metathesis catalysts are shown to display distinct and unexpected reactivity patterns for the metathesis of long-chain α-olefins at low temperatures (< 100 °C). Namely, catalysts based on supported Mo oxo species, whether prepared via wet impregnation or surface organometallic chemistry (SOMC), exhibit strong activity dependencies on the α-olefin chain length, with slower reaction rates for longer substrate chain lengths. In contrast, molecular and supported Mo alkylidenes are highly active and do not display such dramatic dependence on chain length. 2D solid-state NMR analyses of post-metathesis catalysts, complemented by molecular dynamics calculations, evidence that the activity decrease observed for supported Mo oxo catalysts relates to the strong adsorption of internal olefin metathesis products due to interactions with surface Si-OH groups. Overall, this study shows that in addition to the nature and the number of active sites, the metathesis rates and overall catalytic performance depend on product desorption, even in the liquid phase with non-polar substrates. This study further highlights the need to consider adsorption when designing catalysts and the unique activity of molecularly defined supported metathesis catalysts prepared via SOMC.

scholarly journals Air-stable 18-electron adducts of Schrock catalysts with tuned stability constants for spontaneous release of the active species

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Henrik Gulyás ◽  
Shigetaka Hayano ◽  
Ádám Madarász ◽  
Imre Pápai ◽  
Márk Szabó ◽  
...  
Keyword(s):  
High Temperature ◽  
Solid State ◽  
Stability Constants ◽  
Lewis Acid ◽  
Olefin Metathesis ◽  
Acid Treatment ◽  
Active Species ◽  
Activation Process ◽  
Spontaneous Release ◽  
Metathesis Catalysts

AbstractSchrock alkylidenes are highly versatile, very active olefin metathesis catalysts, but their pronounced sensitivity to air still hinders their applications. Converting them into more robust but inactive 18-electron adducts was suggested previously to facilitate their handling. Generating the active species from the inactive adducts, however, required a high-temperature Lewis acid treatment and resulted in an insoluble by-product, limiting the practicality of the methodology. Herein, we introduce an approach to circumvent the inconvenient, costly, and environmentally taxing activation process. We show that 18-electron adducts of W- and Mo-based Schrock catalysts with finite stability constants (typically K = 200–15,000 M−1) can readily be prepared and isolated in excellent yields. The adducts display enhanced air-stability in the solid state, and in solution they dissociate spontaneously, hence liberating the active alkylidenes without chemical assistance.

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