BN-doped fullerenes: An NICS characterization

Heterofullerenes C-58(BN), C-54(BN)(3), C-48(BN)(6), and C-12(BN)(24) and t heir hexaanions as well as the C58(BN) dimer have been investigated by ab i nitio calculations. On the basis of the computed nucleus independent chemic al shifts (NICS) at the cage center and also at the center of individual ri ngs, BN-doped fullerenes C-58(BN), C-54(BN)(3), and C-48(BN)(6) are slightl y more aromatic than C-60, whereas the corresponding hexaanions are signifi cantly less aromatic than CG(60)(6-). The predicted NICS values may be usef ul for the identification of the heterofullerenes through their endohedral He-3 NMR chemical shifts. Compared to C-60, the dimerization of C-58(BN) is calculated to be more exothermic by 16 kcal/mol.