A computational NICS and 13C NMR characterization of BN-substituted 60C fullerenes

DFT calculations are applied to devise NMR parameters of heterofullerenes C60−2x(BN)x (x=1, 2, 3, 6, 9, 12, 15, 18, 21, and 24). The calculated chemical shielding tensors at the sites of 13C nuclei in the first and second neighbor of the doped atoms are perturbed and other distant atoms are not influenced significantly. Chemical shielding of the second neighbor of nitrogen and boron nuclei is significantly shifted to upfield and downfield (the second neighboring effect), respectively. Nucleus independent chemical shifts (NICS) at the cage center of BN-substituted fullerenes demystifies that substituted species are more aromatic than 60C. The predicted NICS values may be useful for identification of the heterofullerenes through their endohedral 3He NMR chemical shifts.