Redox properties of mixed lutetium/yttrium nitride clusterfullerenes: endohedral Lu(x)Y(3-x)N@C80(I) (x = 0-3) compounds.

The redox behavior of mixed lutetium/yttrium nitride clusterfullerenes of the series Lu(x)Y(3-x)N@C(80)(I(h), x = 0-3) is studied for the first time by means of cyclic voltammetry, fast-scan cyclic voltammetry, square-wave voltammetry, and electron paramagnetic resonance (EPR) spectroelectrochemistry. A reversible single-electron-transfer process, which does not result in an EPR signal, is detected during the anodic oxidation sweep of cyclic voltammetry experiments performed at different temperatures (296 and 360 K). The cathodic reduction sweep reveals a rather complex response for all the four clusterfullerenes--with up to three irreversible reduction steps. By correlating the results of fast-scan and square-wave voltammetry and combining them with simulations of the voltammograms, we are able to propose a reduction mechanism for the Lu(x)Y(3-x)N@C(80)(I) (x = 0-3) fullerenes.