Unxepected dimerization of oxidized fullerene-oligothiophene-fullerene triads

Can bulky fullerene substituents reduce the dimerization tendency of oligothiophene radical cations? These authors prepared the dumbbell-shaped bis-C60-substituted oligothiophene shown in the Figure in order to address this question. Contrary to expectation, the molecules display extensive dimerization, even at room temperature, in remarkable contrast to the corresponding unsubstituted oligothiophenes