The oxidation of the following derivatives has been studied by cyclic voltammetry in tetrahydrofuran solvent at a platinum electrode : (Et(3)P)(2)M(eta(2)-C-60, [(Et(3)P)(2)M]C-6(60)) (M = Pt, Pd, Ni; Et = ethyl) and [(Et(3)P)(2)Pt]C-n(60) (n = 2-4). The derivatives containing one organometallic group are oxidized in a two-electron irreversible reaction that cleaves off the metal fragment giving free C-60. As additional platinum-containing groups are added in the series [(Et(3)P)(2)Pt]C-n(60) (n = 1-4), the complexes become successively more easily oxidized. For n = 2 and n = 3, the first step of oxidation involves cleavage of the addend giving the next lower complex until, at the most positive peak, C-60 is produced. For [(Et(3)P)(2)Pt]C-4(60), the first step of oxidation is a one-electron process that shows some chemical reversibility. A second irreversible step may represent a second step of oxidation or be due to a different isomer. The previously reported anodic peak potentials for the complexes n = 1-6, M = Pt, Pd, Ni, vary linearly with n. The sensitivity of the peak potentials to the number of addends is discussed with reference to similar effects seen for the reversible reduction potentials.