Crystalline anionic coordination complexes (PPN+){CpMo(CO)(2)(eta(2)-C-60)}-(1), (PPN+){CpMo(CO)(2)(eta(2)-C-70)}(-center dot)0.5C(6)H(14) (2) and (PPN+){Cp*Mo(CO)(2)(eta(2)-C-60)}-center dot C6H5CN center dot C6H4Cl2 (3) containing cyclopentadienyl (1, 2) and pentamethylcyclopentadienyl (3) molybdenum dicarbonyl eta(2)-coordinated to fullerenes have been obtained by the reaction of the (PPN+)(fullerene(center dot-)) salt with the {Cp(*)Mo(CO)(3(2))}(2) dimers (PPN+ is bis(triphenylphosphoranylidene) ammonium cation). The {CpMo(CO)(2)(eta(2)-C-60(70))}(-) anions contain neutral C-60 and C-70. The optical properties and geometry of the CpMo(CO)(2) moieties in 1 and 2 are similar to those in (PPN+)-{CpMo0(CO)(3)}(-). The analysis of optical data for 3 shows that. 2-coordinated C-60 molecules are more negatively charged in 3 than in 1 and 2. Complexes 1-3 show weak EPR signals indicating that the major part of the samples is EPR silent and diamagnetic. Diamagnetism of the anions in 1-3 is explained by the chemical bond formation between the initially paramagnetic CpMo1(CO)(2) and (fullerene)(center dot-) units. The DFT calculations for 1 and 3 support the diamagnetic singlet ground state for both complexes, in which the singlet-triplet energy gaps calculated at the M11/cc-pVTZ-PP/cc-pVDZ level of theory are about 1.27 and 0.95 eV, respectively. According to the calculations, C-60 molecules are more negatively charged in 3 than in 1 and that can be explained by stronger back donation from the molybdenum moieties to fullerenes.