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.
Titolo: | A Woodward-Hoffmann approach to the C-60 cluster opening leading to homo[6]1fullerenes |
Autore/i: | KEMNER, EWOUT; Hirsch A; ZERBETTO, FRANCESCO |
Autore/i Unibo: | |
Anno: | 2004 |
Rivista: | |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1021/jp047580x |
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. |
Data prodotto definitivo in UGOV: | 2005-10-07 11:51:13 |
Appare nelle tipologie: | 1.01 Articolo in rivista |