Heteronuclear diatomic transition-metal cluster ions in the gas phase: Reactivity and thermochemistry of AgFe+

Abstract

The gas-phase chemistry of AgFe+ was studied by using Fourier transform ion cyclotron resonance mass spectrometry. AgFe+ is unreactive with alkanes but reacts with cyclic and linear (C4–C8) alkenes. The primary reactions are dominated by dehydrogenation and condensation. In addition, cluster splitting is observed in the reaction of AgFe+ with benzene. Secondary reactions generally involve cluster splitting with the loss of Ag, although AgFeC5H 6 + is observed to dehydrogenate cyclopentene to yield AgFeC10H 12 + . Ion-molecule reactions, collision-induced dissociation, and photodissociation experiments were used to determine the bond energiesD°(Fe+−Ag)=53±7 kcal/mol andD°(Ag+−Fe)=46±7 kcal/mol. These values in turn were used to calculateΔH f (AgFe+)=296±7 kcal/mol andIP(AgFe)=6.5±0.3 eV. Related chemical and physical properties of CuFe+ are presented for comparison.