Evaluation by ESCA of the Electronic Effect of Methyl Substitution on the Cyclopentadlenyl Ligand. A Study of Tltanocenes, Zirconocenes, Hafnocenes, and Ferrocenes

ESCA studies of a series of titanocenes, zirconocenes, hafnocenes, and ferrocenes have shown that substitution of methyls for hydrogens on the cyclopentadienyl ligand results in a dramatic electronic effect as reflected by the binding energies of the inner-shell electrons of the metal. The substitution of two pentamethylcyclopentadlenyl groups for cyclopentadienyl ligands Is approximately equivalent to a one-electron reduction of the complexed metal.