Formation of the CuII -Phenoxyl Radical by Reaction of O2 with a CuII -Phenolate Complex via the CuI -Phenoxyl Radical.
Chemistry
; 25(69): 15805-15814, 2019 Dec 10.
Article
em En
| MEDLINE
| ID: mdl-31486552
ABSTRACT
Reaction of Cu(ClO4 )2 â
6 H2 O with a tripodal 2N2O ligand, H2 Me2 NL, having a p-(dimethylamino)phenol moiety, in CH2 Cl2 /MeOH (11 v/v) under basic conditions under an inert gas atmosphere gave [Cu(Me2 NL)(H2 O)] (1). The same reaction carried out under aerobic conditions gave [Cu(Me2 NL)(MeOH)]ClO4 (2), which could be obtained also from the isolated complex 1 by reaction with O2 in CH2 Cl2 /MeOH. The X-ray crystal structures of 1 and 2 revealed similar square-pyramidal structures, but 2 showed the (dimethylamino)phenoxyl radical features. Complex 1 exhibits characteristic CuII EPR signals of the d x 2 - y 2 ground state in CH2 Cl2 /MeOH at 77â
K, whereas 2 is EPR-silent. The EPR and X-ray absorption fine structure (XAFS) results suggest that 2 is assigned to the CuII -(dimethylamino)phenoxyl radical. However, complex 1 showed different features in the absence of MeOH. The EPR spectrum of the CH2 Cl2 solution of 1 exhibits distortion from the d x 2 - y 2 ground state and a temperature-dependent equilibrium between the CuII -(dimethylamino)phenolate and the CuI -(dimethylamino)phenoxyl radical. From these results, CuII -phenoxyl radical complex 2 is concluded to be formed by the reaction of 1 with O2 via the CuI -phenoxyl radical species.
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1
Base de dados:
MEDLINE
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Chemistry
Assunto da revista:
QUIMICA
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Japão