摘要：

Cyclopropane (CP) or methylcyclopropane (MCP) chemisorption on silica-molybdena catalysts photoreduced in CO was found toresult in a sharp increase (by one order of magnitude) of specific activities for olefin metathesis (propene, 1-hexene, ethyloleate). IR and UV-VIS spectroscopic studies revealed that promoting effect of CP and MCP treatment was associated with theformation of the thermally stable carbene complexes Mo = CH2 and Mo=CH-CH3, arising from CP and MCP interaction with low coordinated MO4+ ions in photoreduced Mo/SiO2 IR data showed fast reversible transformation of Mo=CH2 to Mo=CH-CH3 thus providing the first direct spectroscopic confirmation of a chain carbene mechanism of propene metathesis. A generalscheme for CP and MCP interaction with photoreduced Mo/SiO2 was proposed.

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