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 N-14 and C-13 hyperfine couplings (lice). DFT calculations of N-14 and C-13 isotropic lice 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 T-2 and T-1 relaxation times obtained by pulsed methods. (c) 2005 Elsevier B.V. All rights reserved.