Demonstrability of the Photochemical Formation of Biradicals by Magnetic Methods
Abstract
THE red 5,6,11,12-tetraphenylnaphthacene (rubrene) (I) is stable to oxygen in the solid state; its solutions, however, are only stable in the dark. When they are irradiated with sunlight or artificial light in the presence of oxygen, a crystalline peroxide (III) is formed1 (the quantum efficiency of the formation of (III)2 rises to unity at concentrations greater than 0.01 molar and is independent of wave-length between 3660 and 5460 A.). The easy formation of this peroxide is reminiscent of the formation of (V) from solutions containing hexaphenylethane molecules, as well as their dissociation products, namely, the paramagnetic triphenylmethyl radicals (IV). (The schemes and are simplified ones and show in both cases only the initial and final products.)
- Publication:
-
Nature
- Pub Date:
- August 1950
- DOI:
- 10.1038/166307a0
- Bibcode:
- 1950Natur.166..307B