A theoretical study of transition metal complexes of C₆₀ and C₇₀ and their ring-opened alternatives

Abstract

Ring opened structures of C₆₀ and C₇₀ are shown to be stabilized by complexation with transition metal fragments of the form C_nH_nM, where N = 3 to 6 and M = Cr, Mn, Fe, Co, and Rh. The ring opening of C₆₀ and C₇₀ is compared with the reverse process of the well-known catalytic conversion of acetylene into benzene. Calculations at the semi-empirical PM3(tm) level show that the 6-membered ring in C₆₀ and C₇₀ can be opened up in different ways through complexation with transition metal fragment. The mode of ring opening depends on the number of external 5- and 6-membered rings around the 6-membered ring being cleaved. The structures and energetics of the various ring-opened structures are discussed.