Alkyne metathesis with in situ catalysts: W(CO)6 and 4-chlorophenol are efficient in the formation of poly(para-phenyleneethynylene)s

Treatment of several alkyl-substituted dipropynylated benzenes in the presence of tungsten hexacarbonyl and 4-chlorophenol at 150°C leads to the formation of poly(para-phenyleneethynylene)s (PPEs). The obtained PPEs are of moderate molecular weights but form in good to excellent yields. Dihexyl-, dinonyl-, and didodecyl-PPE have been made by this route. It is the first time that a tungsten-containing in situ catalyst system is reported to be active for alkyne metathesis.