Reactions between M+ (M = Si, Ge, Sn and Pb) and benzene in the gas phase

Using a laser ablation/inert buffer gas ion source coupled with a reflectron time-of-flight mass spectrometer, the gas-phase reactions between the IVA group element ions M(+) (M = Si, Ge, Sn and Pb) and benzene seeded in argon gas were studied. In addition to the association reaction pathway (forming [M(C(6)H(6))(x)](+), x = 1, 2, etc.), benzene was dissociated to form complex ions [M(C(5)H(5))](+), [M(C(7)H(5))](+) and [M(C(9)H(x))](+) (x = 5, 7 and 9), etc. DFT theoretical calculations indicated that, in the association products [M(C(6)H(6))](+), the M atom is close to one carbon atom of benzene, while in most of the dissociation complexes, pentagonal structures (M/cyclopentadienyl derivatives) were formed, with the M atom situated near the fivefold axis of the five-membered ring. The bond patterns in these complexes are discussed.