E. Hedaya

Flash Vacuum Pyrolysis. III. Formation and Ionization of Cyclopentadienyl, Cyclopentadienyl Nickel, and Dihydrofulvalene (Dicyclopentadienyl) Derived from Nickelocene

The pyrolysis of nickelocene has been investigated over a wide temperature range (300°–1400°K), at low pressures (∼ 10−3–10−4 torr), and short contact times (∼ 1 msec) in a quartz reactor coupled directly to the ionization source of a mass spectrometer. The cyclopentadienyl and cyclopentadienyl nickel radicals were detected and characterized by their ionization potentials, shutterability, and reactivity with allyl and methyl radicals. The cyclopentadienyl nickel radical, which is produced in relatively low yields, was found to react only with allyl radicals at our conditions while cyclopentadienyl undergoes reactions with both allyl and methyl. Also the cyclopentadienyl radical dimer was detected and its ionization potential measured. Appearance potentials for nickel, cyclopentadienyl, and cyclopentadienyl nickel ions generated from nickelocene on electron impact were obtained. These, in combination with the corresponding ionization potentials, lead to estimates of the dissociation energies of nickelocene...