Triplet-sensitized cycloreversion of the endoperoxides of dimethylhomöocoerdianthrone and heterocoerdianthrone
Abstract
The quantum yield for cycloreversion of the endoperoxide of dimethylhomöocoerdianthrone (HOCDPO) occurring from the triplet manifold was determined by triplet sensitization with benzophenone as sensitizer to be 0.31. The T 2(ππ *) state of HOCDPO is the reactive state. In contrast we found that triplet sensitization of the structurally related endoperoxide of heterocoerdianthrone (HECDPO) does not lead to cycloreversion. The reason for the different behavior is most probably that the unreactive nπ * triplet lies below the ππ * triplet for HECDPO whereas for HOCDPO the sequence is reversed. The energy of the T 2(ππ *) state of HOCDPO is estimated to be 260 kJ/mol.
- Publication:
-
Chemical Physics Letters
- Pub Date:
- September 1989
- DOI:
- 10.1016/0009-2614(89)85112-7
- Bibcode:
- 1989CPL...161..439K