R. Buffon et al., MOLECULAR HETEROGENEOUS METATHESIS CATALYSTS - AN ATTEMPTED SYNTHESISOF SURFACE-ANCHORED ALKYLIDENETUNGSTEN COMPLEXES, Journal of the Chemical Society. Dalton transactions, (12), 1994, pp. 1723-1729
The reactivity of the two alkylidynetungsten complexes. [W(=CCMe3)(CH2
CMe3)3] and [W(=CCMe3)Cl3(dme)] (dme = 1,2-dimethoxyethane), was deter
mined with the surface of different inorganic oxides, such as silica,
alumina, silica-alumina and niobia; their catalytic activity was teste
d for the metathesis of cis-pent-2-ene. The most efficient solids resu
lted from the interaction of these complexes with the surface of parti
ally dehydroxylated niobia and silica-alumina. An attempt to identify
the surface complexes on niobia (most active system) and silica (less
active system) revealed the presence of a number of different anchored
complexes, some of them bearing a neopentylidene ligand. The possible
correlation between catalytic activity and some of the most probable
surface entities is discussed.