Electron attachment to Ni(PF3)4 and Pt(PF3)4

An experimental study has been made of thermal electron attachment to the transition-metal trifluorophosphine complexes Ni(PF3)4 and Pt(PF3)4 using a flowing-afterglow Langmuir-probe apparatus. Both complexes are efficient at electron attachment, although the rate constants are somewhat less than collisional. The rate constant for electron attachment to Ni(PF3)4 is 1.9x10-7 cm3 s-1 at room temperature, about a factor of 2 less than collisional. The activation energy is 39±5 meV for the attachment reaction. The rate constant for electron attachment to Pt(PF3)4 is 5.4x10-8 cm3 s-1 at room temperature, and the activation energy is 84±8 meV. For both complexes, a PF3 ligand is lost on electron attachment, and only the M(PF3)3- ion is observed in the negative-ion mass spectrum. Density functional calculations were carried out on Ni(PF3)4 and various fragments in order to describe the thermochemistry of the attachment reaction