Boron-nitrogen (BN) substitution patterns in C/BN hybrid fulterenes: C60-2x(BN)(x) (x=1-7)

Semiempirical AM1 and MNDO and density functional theory (B3LYP/3-21G and 6 -31G*) are used to examine the relative stability of various isomers of suc cessive BN substituted fullerenes C-60-(2x)(BN)(x), where x = 1 -7. It is f ound that stability is enhanced by keeping BN units and BN filled hexagons adjacent to one another. Successive BN substitution prefers N site attachme nt to the existing BN chain. The localization of MOS shows that lone-pairs of nitrogen atoms reside "inside" the cage, which may be the reason for out ward displacement of N atoms. Geometric parameters and charge distribution of the carbon region of hybrid fullerenes are not much perturbed by BN subs titution. Band gap (HOMO-LUMO gap), ionization potential, and electron affi nities strongly depend on the number of BN units and filling of the hexagon s. Partially BN filled hexagons or unsaturated BN fullerenes have a stronge r effect than completely filled hexagons on perturbing these properties.