Single site silica supported tetramethyl niobium by the SOMC strategy: synthesis, characterization and structure–activity relationship in the ethylene oligomerization reaction

Abstract

A silica supported tetramethyl niobium complex [(SiO)NbMe₄] 2 has been isolated by the surface alkylation of [(SiO–)NbCl₃Me] 1 with dimethyl zinc in pentane. 1 can be easily synthesized by grafting NbCl₃Me₂ onto the surface of partially dehydroxylated silica by the SOMC strategy. Precise structural analysis was carried out using FTIR, advanced solid state NMR, elemental analysis and mass balance techniques (gas quantification after treating 2 with degassed water). Complex 1 was found to be active in the ethylene oligomerization reaction, producing up to C₃₀, whereas to our surprise complex 2 selectively dimerized ethylene into 1-butene in the absence of a co-catalyst at the same conversion level.