The electrocyclic valence isomerization interconverting bismethano[60]fullerenes 1 and 2 with 1,2,3,6-(type I) and 1,2,3,4-addition patterns (type II) into the corresponding cluster-opened bismethanohomo[60]fullerenes was investigated computationally with respect to the energy profile and to the retention of molecular orbital symmetry. Whereas for 1 the closed form is unstable and spontaneously isomerizes to the cluster-open adduct, the energy difference between the open and closed isomers of 2 is comparatively small. The B3LYP/6-31G* energy of open 2 is only 1.2 kcal mol(-1) higher than that of the closed form. Analysis of the frontier orbital symmetries of 1, 2, and the [5,6]-bridged methano-homo[60]fullerene 3 showed that during these electrocylic valence isomerizations the orbital symmetry is retained and, as a consequence, a Woodward-Hoffmann-type selection principle is valid.
Kemner E, Hirsch A, Zerbetto F (2004). A Woodward-Hoffmann approach to the C-60 cluster opening leading to homo[6]1fullerenes. JOURNAL OF PHYSICAL CHEMISTRY. A, MOLECULES, SPECTROSCOPY, KINETICS, ENVIRONMENT, & GENERAL THEORY, 108, 7135-7138 [10.1021/jp047580x].
A Woodward-Hoffmann approach to the C-60 cluster opening leading to homo[6]1fullerenes
KEMNER, EWOUT;ZERBETTO, FRANCESCO
2004
Abstract
The electrocyclic valence isomerization interconverting bismethano[60]fullerenes 1 and 2 with 1,2,3,6-(type I) and 1,2,3,4-addition patterns (type II) into the corresponding cluster-opened bismethanohomo[60]fullerenes was investigated computationally with respect to the energy profile and to the retention of molecular orbital symmetry. Whereas for 1 the closed form is unstable and spontaneously isomerizes to the cluster-open adduct, the energy difference between the open and closed isomers of 2 is comparatively small. The B3LYP/6-31G* energy of open 2 is only 1.2 kcal mol(-1) higher than that of the closed form. Analysis of the frontier orbital symmetries of 1, 2, and the [5,6]-bridged methano-homo[60]fullerene 3 showed that during these electrocylic valence isomerizations the orbital symmetry is retained and, as a consequence, a Woodward-Hoffmann-type selection principle is valid.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
