Unraveling the electron spin resonance pattern of nonsymmetric radicals with 30 fluorine atoms: electron spin resonance and vis-near-infrared spectroelectrochemistry of the anion radicals and dianions of C60(CF3)(2n) (2n = 2-10) derivatives and density functional theory-assisted assignment.

The charged states of C(60)(CF(3))(2n) (2n = 2-10) derivatives have been studied by electron spin resonance (ESR) and vis-near-infrared (NIR) spectroelectrochemistry. The anion radicals and diamagnetic dianions were furthermore described by theoretical calculations. The ESR spectra of anion radicals exhibit complex patterns due to multiple CF(3) groups. Their interpretation is accomplished by DFT calculations with B3LYP functional. It is shown that calculations provide reliable results when the extended aug-cc-pCVTZ basis set is used for fluorine atoms; however, specially tailored basis sets such as EPR-III also give very similar results with only a fraction of the computational cost. Absorption spectra of the anions exhibit NIR absorption bands, whose assignment is provided by time-dependent DFT calculations.