Cationic molybdenum oxo alkylidenes stabilized by N-heterocyclic carbenes: from molecular systems to efficient supported metathesis catalysts

Janis V Musso; Jordan De Jesus Silva; Mathis J Benedikter; Jonas Groos; Wolfgang Frey; Christophe Copéret; Michael R Buchmeiser

doi:10.1039/d2sc03321f

Cationic molybdenum oxo alkylidenes stabilized by N-heterocyclic carbenes: from molecular systems to efficient supported metathesis catalysts

Chem Sci. 2022 Jul 12;13(29):8649-8656. doi: 10.1039/d2sc03321f. eCollection 2022 Jul 29.

Authors

Janis V Musso¹, Jordan De Jesus Silva², Mathis J Benedikter¹, Jonas Groos¹, Wolfgang Frey³, Christophe Copéret², Michael R Buchmeiser^{1

4}

Affiliations

¹ Institute of Polymer Chemistry, University of Stuttgart Pfaffenwaldring 55 D-70569 Stuttgart Germany michael.buchmeiser@ipoc.uni-stuttgart.de.
² Department of Chemistry and Applied Biosciences, ETH Zürich Vladimir-Prelog-Weg 1-5 CH-8093 Zürich Switzerland ccoperet@ethz.ch.
³ Institute of Organic Chemistry, Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany.
⁴ German Institutes of Textile and Fiber Research (DITF) Denkendorf Körschtalstr. 26, 73770 Denkendorf Germany.

Abstract

Cationic d⁰ group 6 olefin metathesis catalysts have been recently shown to display in most instances superior activity in comparison to their neutral congeners. Furthermore, their catalytic performance is greatly improved upon immobilization on silica. In this context, we have developed the new family of molecular cationic molybdenum oxo alkylidene complexes stabilized by N-heterocyclic carbenes of the general formula [Mo(O)(CHCMe₃)(IMes)(OR)[X^-]] (IMes = 1,3-dimesitylimidazol-2-ylidene; R = 1,3-dimesityl-C₆H₃, C₆F₅; X^- = B(3,5-(CF₃)₂C₆H₃)₄ ^-, B(Ar^F)₄, tetrakis(perfluoro-t-butoxy)aluminate (PFTA)). Immobilization of [Mo(O)(CHCMe₃)(IMes)(O-1,3-dimesityl-C₆H₃)⁺B(Ar^F)₄ ^-] on silica via surface organometallic chemistry yields an active alkene metathesis catalyst that shows the highest productivity towards terminal olefins amongst all existing molybdenum oxo alkylidene catalysts.