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An ESR study of photochemical reactions of Co 2 (CO) 6 (PBu 3 ) 2 with quinones and phenothiazine
Author(s) -
RongZhuang Yan,
HanQing Wang
Publication year - 1985
Publication title -
acta chimica sinica english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 0256-7660
DOI - 10.1002/cjoc.19850030202
Subject(s) - chemistry , phenothiazine , photochemistry , semiquinone , radical , cobalt , photodissociation , electron paramagnetic resonance , adduct , medicinal chemistry , redox , inorganic chemistry , organic chemistry , nuclear magnetic resonance , pharmacology , medicine , physics
Abstract The photochemical reactions of Co 2 (CO) 6 (PBu 3 ) 2 with various quinones and phenothiazine were studied by ESR. The results indicate that the photolysis of Co 2 (CO) 6 (PBu 3 ) 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 Co 2 (CO) 6 (PBu 3 ) 2 was irradiated in the presence of p ‐quinones, only the para‐semiquinone radicals were observed. The photolysis of Co 2 (CO) 6 (PBu 3 ) 2 with phenothiazine in toluene yields phenothiazine radical. The sixteen and eighteen electrons rule have been used to account for these observations.