THEORETICAL-STUDIES ON THE SUBSTITUTED FULLERENES C60-X-YBXNY (X+Y=2)

The equilibrium structures, relative stabilities of substituted fuller enes C58B2, C58N2 and C58BN have been studied at the AM1, PM3, MNDO an d INDO level. The calculation results obtained by all these semi-emper ical methods show that the substituted fullerenes are less stable than C-60. 6-6 isomers are the most stable species for C58B2, C58N2 and C5 8BN, the stabilities decrease with the increase of the distance betwee n the heteroatoms. The calculation results also show that the stabilit y of C58BN is considerably higher than that of C58N2, and the stabilit y of C58N2 is considerably higher than that of C58B2 Calculations on t he C58B2-(NH3)(2) adducts have been employed in this paper to evaluate Smally's proposition on the substitute preference of C58B2 The elctro nic spectra for these doped fullerenes have been calculated using INDO /CIS method. (C) 1998 Elsevier Science B.V. All rights reserved.