Multifrequency EPR study and DFT calculations of a C60 bisadduct anion

The monoanion of bis-TRANS2-[N-methyl-3,4-fulleropyrrolidine] (TRANS2−) was investigated by continuous wave (CW) and pulsed EPR. X-band spectra showed signals due to 14N and 13C hyperfine couplings (hcc). DFT calculations of 14N and 13C isotropic hcc were performed on TRANS2− for different conformations of the pyrrolidinic rings. Calculated values, averaged over the conformations, match well with the experimental values. Accurate g-tensor principal values were obtained by high frequency EPR. The possible dynamical processes affecting the electron spin relaxation are discussed to explain the temperature dependence of the EPR line widths and of the T2 and T1 relaxation times obtained by pulsed methods.