THE X-RAY PHOTOELECTRON SPECTRA OF SIGMA AND Pi BONDED ORGANOGADOLINIUM COMPOUNDS: A SEARCH FOR 4f ORBITAL COVALENCY

Abstract
The nature of the bonding in a series of sigma- and pi-bonded organogadolinium compounds (GdCl3, CpGdCl2, Cp2GdCl, Cp3Gd, Cp2GdR where R=CH3 and C≡CpH) have been studied by x-ray photoelectron spectroscopy. The Gd(3d) region of each compound investigated reveals one electron ‘shake-up’ photopeak indicating some covalency due to 4f participation in bonding. The relative areas of the main photopeak and the satellite photopeak show no change between compounds which indicates similar bonding properties for the various sigma- and pi-bonded substituents. As a result, this investigation finds no support for the hypothesis that sigma-bonded organolanthanide derivatives are more ‘covalent’ than their pi-bonded analogs.