Oxa- and thia-fullerenes (C59O, C59S): Closed or opened cages?

Abstract

Novel structures of oxa- and thia-fullerenes at various oxidation states have been computed systematically for the first time. At the B3LYP/6-31G* density functional level of theory, the most stable C₅₉O, C₅₉O⁴⁻ and C₅₉S⁴⁻ represent cage opened structures with an eight-membered-ring orifice, bearing CO or CS moieties and two fused five-membered rings. On the other hand, C₅₉S, C₅₉S²⁺ and C₅₉O²⁺ are cage closed fullerenes. The calculated nucleus independent chemical shifts (NICS) of all these compounds are presented.