Nature of the Cycloheptatrienyl-Transition Metal Bond. A Study of Electron Distribution in the Mixed-Ring Sandwich Molecules [Ti(.eta.-C7H7)(.eta.-C5H5)], [Nb(.eta.-C7H7)(.eta.-C5H5)], [Ta(.eta.-C7H7)(.eta.-C5H4Me)], and [Mo(.eta.-C7H7)(.eta.-C5H5)] by Photoelectron Spectroscopy with Variable Photon Energy | doi.page