Gas-Phase Study of the Chemistry and Coordination of Lead(II) in the Presence of Oxygen-, Nitrogen-, Sulfur-, and Phosphorus-Donating Ligands

Using a pickup technique in association with high-energy electron impact ionization, complexes have been formed in the gas phase between Pb2+ and a wide range of ligands. The coordinating atoms are oxygen, nitrogen, sulfur, and phosphorus, together with complexes consisting of benzene and argon in association with Pb2+. Certain ligands are unable to stabilze the metal dication, the most obvious group being water and the lower alcohols, but CS2 is also unable to form [Pb(CS2) N ]2+ complexes. Unlike many other metal dication complexes, those associated with lead appear to exhibit very little chemical reactivity following collisional activation. Such reactions are normally promoted via charge transfer and are initiated using the energy difference between M2+ + e- → M+ and L → L+ + e-, which is typically ∼5 eV. In the case of Pb2+, this energy difference usually leads to the appearance of L+ and the loss of a significant fraction of the remaining ligands as neutral species. In many instances, Pb+ appears as a charge-transfer product. The only group of ligands to consistently exhibit chemical reactivity are those containing sulfur, where a typical product might be PbS+(L) M or PbSCH3 +(L) M .