PM7 semiempirical study of C₆₀ fullerene doped with transition metals

En el presente trabajo se reportan cálculos semiempíricos utilizando el método PM7 para el estudio de fullerenos de tipo Cn con n = 60 y fullerenos dopados con metales de transición Cn-1X, con X = Fe, Co, Ni, Cu, Pd, Ag, Pt y Au. Se investigaron las propiedades estructurales, energéticas y electrónicas. Se optimizó la estructura del fullereno C60 y luego se sustituyó por separado, un átomo de carbono por los diferentes átomos metálicos en estudio.La estructura del fullereno resulta modificada solamente en la proximidad del átomo dopante. Los resultados indican que existen algunas interacciones entre los carbonos Cn-1 y los átomos X. La diferencia de energía entre orbitales de frontera, ΔE, muestra una tendencia decreciente respecto al sistema C60 que varía desde 6,7 eV para el sistema original a 4,8 eV para el sistema dopado C59Au.In this research work semiempirical calculations are reported using the PM7 method for the study of fullerenes of type Cn with n=60 and fullerenes doped with metals of transition Cn-1X, with X= Fe, Co, Ni, Cu, Pd, Ag, Pt and Au. Structural, energetic and electronic properties were investigated: The structure of fullerene C60 was optimized and then a carbon atom for the different metallic atoms in study was replaced separately. The structure of the fullerene was modified only in the proximity of the doped atom. Results indicate that there are some interactions between carbons Cn-1 and atoms X. The energy difference between orbital of border, ΔE, shows a decreasing tendency with regard to the system C60 that changes from 6,7 eV for the original system 4,8 eV to the doped system C59Au. Both the ionization potential and the ΔE show the same tendency for the different structures, being the biggest value for original system. The least value of the heat of formation corresponds to C60 with 831 kcal/mol, the closest to this is 845 kcal/mol for C59Fe, being more value remote the C59Au with 993 kcal/mol which is the least stable structure.Facultad de Ciencias ExactasCentro de Química Inorgánic