SOMC-designed silica supported tungsten oxo imidazolin-2-iminato methyl precatalyst for olefin metathesis reactions

International audienceSynthesis, structure, and olefin metathesis activity Of a surface complex [( Si-O-)W(= O)(cH(3))(2)-Im(Dipp)N] (4) (Im(Dipp) = 1,3-bis(2,6-diiSopropylphenyl)-imidazolin-2-iminato) supported on silica by a surface organometallic chemistry (SOMC) approach are reported. The reaction of N-Silylated 2-iminoimidazoline with tungsten (VI) oxytettachloride generated the tungsten oxo imidazolin-2-iminato chloride complex [Im(Dipp)NW(= O)Cl-3] (2). This was grafted on:-partially dehydroxylated silica pretreated at 700 degrees C (SiO2-700) to afford a well-defined mOnopodal surface complex [( Si-O-)W(= O)Cl-2,-Im(Dipp)N] (3). 3 underwent alkylation by ZnMe2 to produce [( Si-O-)W(= O)(CH3)(2)-Im(Dipp)N] (4). The alkyIated surface complex was thoroughly characterized by solid-state NMR, elemental microanalysis, Randan, FT-IR spectroscopies, and XAS analysis. 4 proved to be an active precatalyst for self-metathesis of terminal Olefins such as propylene and 1-hexene