Controlling the hydrogenolysis of silica-supported tungsten pentamethyl leads to a class of highly electron deficient partially alkylated metal hydrides

Abstract

Accessing highly electron deficient partially alkylated tungsten hydrides on silica via controlled hydrogenolysis of surface organometallic complex (Si–O–)W(Me)5.

SOMC grafting of vanadium oxytriisopropoxide (VO(OiPr)3) on dehydroxylated silica; analysis of surface complexes and thermal restructuring mechanism

“…The ability of the strained siloxane bridges of highly dehydroxylated silica to participate in graing reactions and in the rearrangement of surface complexes by s-bond metathesis is known. 31,36,39 The rearrangement of 2m to 2b does not generate new silanol moieties in agreement with the lack of such functionalities in 2 as observed by FT-IR (Fig. 1).…”

Reactive surface organometallic complexes observed using dynamic nuclear polarization surface enhanced NMR spectroscopy

“…S11, ESI†). This most likely indicates that the pores are not fully impregnated immediately, and that diffusion of the solvent into the materials can continue over a period of days 49 (a similar behavior was also observed for MOFs 27 ).…”

“…The spectrum consists of one major peak at –100 ppm indicating that most silicon atoms are present as Q 4 and Q 3 -sites, 20,48 and most interestingly a weak signal at –16 ppm is assigned to methyl-transfer to Si, arising from the formation of bipodal species, which can occur at room temperature. 49 …”

Transmission and fluorescence X-ray absorption spectroscopy cell/flow reactor for powder samples under vacuum or in reactive atmospheres

“…3 Supported catalysts are usually synthesized by reacting metal-containing precursors with support surfaces to form precatalysts, which are treated in gases to alter the metal oxidation state and/or the structures of the metal-containing species. 4,5 Because many catalysts at various stages of preparation and use are reactive with O 2 , moisture, and/or CO 2 , they require handling in inert-atmosphere glove boxes and sealed sample transfer devices and XAS cells. 6 Metal loadings in the range of 0.1-1.0 wt.…”