Patterns for addition to C59BH

Abstract

Semiempirical AM1 and MNDO methods are used to examine the relative stability of the different isomers of C₅₉BHX_2n (X = H, F; n = 1,2). The energies show that the most stable isomer of C₅₉BH₃ is the 5,6-isomer, which is a 1,2-adduct of C₅₉BH; however, for C₅₉BH₅, 7,24,11,27-isomer is the most energetically preferred structure, which is a 1,4/1,4-adduct of C₅₉BH. The addition patterns of C₅₉BHF₂ is different from that of C₅₉BH₃, 7,24-isomer (a 1,4-adduct of C₅₉BH), is the lowest energy structure, while for C₅₉BHF₄, the most energetically preferred structure corresponds to 7,24,11,27-isomer of C₅₉BH₅. Comparing the patterns for addition to C₅₉BH and to C₅₉HN, the calculation results indicate that the regioselectivity of this type of heterofullerenes is not only related to the doping heteroatom but also related to the adding group. The NICS of some isomers' are calculated for comparing their aromaticity. The predicted NICS values indicate that aromaticity may be the primary factor to stabilize the 1,2- and 1,4-adducts of C₅₉BH.