Electronic structure of transition-metal indenyl compounds: a He I and He II photoelectron spectroscopic study of [Mn(η5-C9H7)(CO)3], [ Fe(η5-C9H7)2], [Ru(η5-C9H7)2], and [Ru(η5-C9H7)η-C5Me5)]

Abstract

He I and He II photoelectron spectra have been recorded for [Mn(η⁵-C₉H₇)(CO)₃], [Fe(η⁵-C₉H₇]₂, [Ru(η⁵-C₉H₇)₂] and [Ru(η⁵-C₉H₇)(η-C₅Me₅)] and assigned by comparison with the photoelectron-spectra of related cyclopentadienyl complexes and with the help of extended-Hückel molecular-orbital calculations. The indenyl complexes have lower first ionization energies than the cyclopentadienyl complexes showing the idenyl ligand to be electron releasing relative to cyclopentadienyl, and comparable to methylcyclopentadienyl in its donor power.