Photoelectron spectra of cyclopentadienyl derivatives of mercury, thallium, indium, tin and lead

Abstract

The photoelectron spectra of HgCp₂, TlC_p, InCp, SnCp₂ and PbCp₂(Cp = cyclopentadienyl, C₅H₅) are reported and interpreted in the light of the structures assigned to these compounds and the photoelectron spectra of other metal cyclopentadienyls. The results do not support the separation of covalent centrally-bonded cyclopentadienyls into π-bonded and σ-bonded classes; the evidence suggests that π-bonding of some type is essential for formation of the centrally-bonded structure, and that when it is not possible or effective the peripherally-bonded structure, which may or may not be subject to fluxional behaviour, is adopted.