Redox-active films formed by electrochemical reduction of solutions of C₆₀ and platinum complexes

Electroreduction of a toluene-acetonitrile (4:1 v/v) solution of C₆₀ and cis-Pt(py)₂Cl₂ in the presence of 0.10 M tetra(n-butyl)ammonium perchlorate as supporting electrolyte produces a black, redox active film that coats the electrode surface. This film retains its redox activity when transferred to an acetonitrile solution that contains only the supporting electrolyte, 0.10 M tetra(n-butyl)ammonium perchlorate. The film has been characterized by infrared spectroscopy, laser desorption mass spectrometry, and XPS spectroscopy. The formation of this film is dependent on the platinum complex used as precursor and on the potential range utilized during film growth. No film growth is observed when Pt(bipy)Cl₂, Pt(py)₂I₂, cis-Pt(PPh₃)₂Cl₂ or trans-Pt(py)₂Cl₂ are used as precursors, but {Pt(μ-Cl)Cl(C₂H₄)}₂ is a useful precursor which allows film growth at less negative potentials. Chemically prepared C₆₀Pt₁ is also electrochemically active when precipitated on a platinum electrode. The formation of an electroactive film from the electroreduction of C₇₀ and cis-Pt(py)₂Cl₂ is also reported.