Computational modeling of the structure of large molecules: I. molecule C60H12 and cluster C852

Structural parameters of dodecahydro-Buckminster fullerene C₆₀H₁₂ and its derivative, the carbon cluster C₈₅₂ consisting of a central C₆₀ dodecaradical and twelve peripheral C₆₀ diradicals connected by eighteen-C≡C-C≡C-bridges, are calculated using a PM3 quantum-chemical method. The C₆₀H₁₂ molecule and the central fragment of the cluster each contain eight quasiaromatic six-membered rings with bond lengths of 1.38 and 1.43 Å. The calculations we performed using the GAMESS package and an original algorithm for diagonalization of dense symmetric matrices.