Variable Photon Energy Photoelectron Spectroscopy and Magnetism of YbCp3 and LuCp3

The first examples of gas-phase photoelectron spectra of ytterbium and lutetium complexes are reported. Variable photon energy photoelectron spectroscopy of YbCp3 (Cp=?-C5H5) shows that f electron ionization gives ion states corresponding to both 4f12 and 4f13 configurations, whereas that of LuCp3 reveals only 4f13 ion states. Magnetic data on crystalline YbCp3 display Curie behavior between 20 and 305 K with a magnetic moment of 3.53 ?B. Both the photoelectron spectra and the magnetic moment are consistent with the proposal that YbCp3 has a mixed configuration ground state with the unpaired spin residing both in an f orbital and on the cyclopentadienyl ligands.