| Abstract: | The photochemical reactions of Co2(CO)6(PBu3)2 with various quinones and phenothiazine were studied by ESR. The results indicate that the photolysis of Co2(CO)6(PBu3)2 in the presence of o-quinones led to the observation of an ESR spectrum, showing a broad 8 or 12 groups of hyperfine lines due to interaction with cobalt (Co, 1 = 7/2). The results show that with o-quinones the cobalt radical adducts are formed via metal chelation to the carbonyl oxygens. However, when Co2(CO)6(PBu3)2 was irradiated in the presence of p-quinones, only the para-semiquinone radicals were observed. The photolysis of Co2(CO)6(PBu3)2 with phenothiazine in toluene yields phenothiazine radical. The sixteen and eighteen electrons rule have been used to account for these observations. |
