FORMATION OF REDOX-ACTIVE, 2-COMPONENT FILMS BY ELECTROCHEMICAL REDUCTION OF C-60 AND TRANSITION-METAL COMPLEXES

Electrochemical reduction of C-60 in 4:1 toluene/acetonitrile solution in the presence of (PhCN)(2)PdCl2, Ir(CO)(2)Cl(p-toluidine), or (CF3C o2)(4)Rh-2 produces three different, redox-active, black films that co at the electrode. These films are insoluble in common organic solvents and adhere strongly to the electrode surface. Film formation has been monitored by multiscan cyclic voltammetry, which gives information ab out the requirements for film growth. The three different films (on th e original electrodes) can be transferred to a solution of acetonitril e that contains only the supporting electrolyte, tetra(n-butyl)ammoniu m perchlorate, where the films retain their redox activity. Each film displays a significant decrease in resistivity (i.e. a window of condu ctivity) in the potential region in which it is grown and in which it displays redox activity. The films have been examined by scanning elec tron microscopy, which shows variations in the nature of the three fil ms' morphologies with the film formed from (PhCN)(2)PdCl2 displaying t he greatest uniformity and smoothest surface. Analysis of the films by infrared spectroscopy and laser desorption mass spectrometry reveals that intact C-60 units are present within each film. Treatment of the palladium/C-60 film with triphenylphosphine results in film dissolutio n and the formation of the previously characterized complex, (eta(2)-C -60)Pd(PPh3)(2) The rhodium/C-60 film dissolves in pyridine and F-19{H -1} NMR spectroscopy reveals that (CF3CO2)(4)Rh-2 is extracted intact from the film. The structure of the films is discussed in terms of cov alent bonding between the fullerenes and the metal atoms or complexes within the film.