scholarly journals Well-defined silica supported bipodal molybdenum oxo alkyl complexes: a model of the active sites of industrial olefin metathesis catalysts

2017 ◽  
Vol 53 (82) ◽  
pp. 11338-11341 ◽  
Author(s):  
Nicolas Merle ◽  
Frédéric Le Quéméner ◽  
Samir Barman ◽  
Manoja K. Samantaray ◽  
Kai C. Szeto ◽  
...  
Keyword(s):  
Olefin Metathesis ◽  
Active Sites ◽  
Alkyl Complexes ◽  
Metathesis Catalysts

A novel well-defined supported bipodal molybdenum alkyl oxo species for “modelling MoO3/SiO2 industrial catalysts” that efficiently catalyzes olefin metathesis has been unveiled.

d0Re-Based Olefin Metathesis Catalysts, Re(⋮CR)(CHR)(X)(Y):  The Key Role of X and Y Ligands for Efficient Active Sites

2005 ◽  
Vol 127 (40) ◽  
pp. 14015-14025 ◽  
Author(s):  
Xavier Solans-Monfort ◽  
Eric Clot ◽  
Christophe Copéret ◽  
Odile Eisenstein
Keyword(s):  
Olefin Metathesis ◽  
Active Sites ◽  
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.

Activated Hoveyda‐Grubbs Olefin Metathesis Catalysts Derived from a Large Scale Produced Pharmaceutical Intermediate—Sildenafil Aldehyde

2021 ◽  
Author(s):  
Louis Monsigny ◽  
Jakub Piątkowski ◽  
Damian Trzybiński ◽  
Krzysztof Wozniak ◽  
Tomasz Nienałtowski ◽  
...  
Keyword(s):  
Olefin Metathesis ◽  
Large Scale ◽  
Metathesis Catalysts

Nitrenium ions and trivalent boron ligands as analogues of N-heterocyclic carbenes in olefin metathesis: a computational study

2015 ◽  
Vol 44 (46) ◽  
pp. 20021-20026 ◽  
Author(s):  
A. Pazio ◽  
K. Woźniak ◽  
K. Grela ◽  
B. Trzaskowski
Keyword(s):  
Olefin Metathesis ◽  
Computational Study ◽  
Heterocyclic Carbenes ◽  
Mechanistic Study ◽  
Nitrenium Ions ◽  
Nitrenium Ion ◽  
Metathesis Catalysts

A DFT mechanistic study reveals that nitrenium ion-modified Hoveyda-like complexes are good candidates for latent metathesis catalysts, while boron-modified systems are candidates for very fast metathesis catalysts.

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