Ozonides, epoxides, and oxidoannulenes of C(70).
Six new monoadducts of C(70) with oxygen species have been prepared, isolated, and characterized following ozonation of C(70) solutions. The initial products are two ozonide monoadducts, identified as a,b- and c,c-C(70)O(3). These ozonides lose O(2) through thermolysis or photolysis to form various isomers of C(70)O. The a,b-C(70)O(3) isomer dissociates through thermolysis with a decay time of 14 min at 296 K to form the [6,6]-closed epoxide a,b-C(70)O. When photolyzed, it instead forms a [5,6]-open oxidoannulene identified as a,a-C(70)O. These reactions mimic those seen for C(60)O(3). By contrast, the c,c-C(70)O(3) isomer, which has a thermolysis lifetime of 650 min at 296 K, decays thermally only to an oxidoannulene deduced to be d,d-C(70)O. Photolysis of c,c-C(70)O(3) produces a mixture of the oxidoannulenes b,c-C(70)O and c,d-C(70)O plus a minor amount of the c,c-epoxide. All four C(70)O oxidoannulene isomers undergo photoisomerization, giving eventually the a,b- and c,c-C(70)O epoxides.
Heymann
Dieter
D
Department of Earth Science, Rice Quantum Institute, Rice University, Houston, Texas 77251, USA.
Bachilo
Sergei M
SM
Weisman
R Bruce
RB