Theoretical study of molecular and photophysical properties of [5, 6]-open C 60 derivatives

Abstract

Configurations of four [5, 6]-open C 60 monoadducts have been optimized at B3LYP/6-31G* level. The calculated geometrical structures show that the bonds at the junction between five- and six-membered rings break and the planar properties of pentagon and hexagon rings in the vicinity of functionalized groups disappear for these C 60 derivatives. On the basis of the optimized geometrical structures, their excitation energies and third-order nonlinear optical polarizabilities have been calculated at TDB3LYP/3-21G* level coupled with sum-over-states method for these C 60 monoadducts. The obtained results show that different functionalized groups result in different effects on HOMO–LUMO gap and different optical property for [5, 6]-open C 60 derivatives. The absorption spectra of the derivatives, in which a nitrogen atom bridges the functionalized groups to C 60 cage, show a red shift compared with those of the derivatives in which a carbon atom becomes as the connection.