Tungsten(II) chlorocarbonyls as alkene metathesis, arene alkylation and alkyne polymerization catalysts

Article abstract of DOI:10.1016/S1381-1169(97)00059-9

Tungsten(II) chlorocarbonyl compound obtained by photochemical oxidation of W(CO)₆ with CCl₄ is an active alkene metathesis catalyst, free of any organometallic component. This indicates that the initially formed alkylidene ligand must come from the alkene. In toluene solution the same tungsten(II) compound also acts as a highly active catalyst for the transformation of alkenes to alkyltoluenes. Tungsten(II) compounds, which are formed in photochemical oxidation of W(CO)₆ with Group 14 tetrahalides, are extremely reactive at 25°C in phenylacetylene polymerization. The results reported here clearly demonstrate that the formation of tungsten(II) might be an important event in the creation by Lewis acids (Group 14 tetrachlorides) of the catalytic activity of tungsten(0) compounds.