Synthesis and characterization of a homogeneous and silica supported homoleptic cationic tungsten(vi) methyl complex: application in olefin metathesis

Raju Dey; Manoja K Samantaray; Albert Poater; Ali Hamieh; Santosh Kavitake; Edy Abou-Hamad; Emmanuel Callens; Abdul-Hamid Emwas; Luigi Cavallo; Jean-Marie Basset

doi:10.1039/c6cc05352a

Synthesis and characterization of a homogeneous and silica supported homoleptic cationic tungsten(vi) methyl complex: application in olefin metathesis

Chem Commun (Camb). 2016 Sep 13;52(75):11270-11273. doi: 10.1039/c6cc05352a.

Affiliations

¹ King Abdullah University of Science & Technology, KAUST Catalysis Center (KCC), 23955-6900 Thuwal, Saudi Arabia. jeanmarie.basset@kaust.edu.sa.
² King Abdullah University of Science & Technology, KAUST Catalysis Center (KCC), 23955-6900 Thuwal, Saudi Arabia. jeanmarie.basset@kaust.edu.sa and Institut de Quìmica Computacional i Catàlisi and Departament de Quìmica, Universitat de Girona, Campus de Montilivi, 17003 Girona, Catalonia, Spain.
³ Imaging and Characterization Core Lab, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.

PMID: 27709169
DOI: 10.1039/c6cc05352a

Abstract

A method for the synthesis of a homogeneous cationic tungsten(vi)pentamethyl complex [(WMe₅)⁺(C₆F₅)₃BMe^-] from neutral tungstenhexamethyl (WMe₆) and a silica supported cationic tungstentetramethyl complex [([triple bond, length as m-dash]Si-O-)WMe₄⁺ (C₆F₅)₃BMe^-] from a neutral silica supported tungstenpentamethyl complex [([triple bond, length as m-dash]Si-O-)WMe₅] is described. In both cases a direct demethylation using the B(C₆F₅)₃ reagent was used. The aforesaid complexes were characterized by liquid or solid state NMR spectroscopy. Interestingly, the homogeneous cationic complex [(WMe₅)⁺(C₆F₅)₃BMe^-] shows moderate activity whereas the supported cationic complex [([triple bond, length as m-dash]Si-O-)WMe₄⁺(C₆F₅)₃BMe^-] exhibits good activity in olefin metathesis reactions.