Generation of perfluoropolyphenylene oligomers via carbon-fluorine bond activation by Cp2Zr(C6F5)2:: A dual mechanism involving a radical chain and release of tetrafluorobenzyne

The thermal decomposition of Cp2Zr(C6F5)(2) in THF results in the slow formation of Cp2Zr(C6F5)F and tetrafluorobenzyne. The tetrafluorobenzyne is trapped by THF to give several products. The same reaction performed in the presence of durene or furan also results in the formation of Cp2Zr(C6F5)F and the respective Diels-Alder adducts of tetrafluorobenzyne. If Cp2Zr(C6F5)(2) is heated in the presence of C6F6, linear chains of perfluoroarenes are rapidly generated along with Cp2Zr(C6F5)F. The disappearance of Cp2Zr(C6F5)(2) is observed to slow dramatically after 30-80% completion, with the extent of reaction being inversely dependent on the concentration of C6F6. Dual mechanisms involving a rapid radical chain-and a slower tetrafluorobenzyne producing reaction are proposed to account for these observations.