Reversible carbon-carbon bond formation induced by oxidation and reduction at a redox-active cobalt complex.
Inorg Chem
; 52(9): 5403-17, 2013 May 06.
Article
em En
| MEDLINE
| ID: mdl-23594241
ABSTRACT
The electronic structure of the diamagnetic pyridine imine enamide cobalt dinitrogen complex, ((iPr)PIEA)CoN2 ((iPr)PIEA = 2-(2,6-(i)Pr2-C6H3NâCMe)-6-(2,6-(i)Pr2-C6H3NCâCH2)C5H3N), was determined and is best described as a low-spin cobalt(II) complex antiferromagnetically coupled to an imine radical anion. Addition of potential radical sources such as NO, PhSSPh, or Ph3Cl resulted in C-C coupling at the enamide positions to form bimetallic cobalt compounds. Treatment with the smaller halocarbon, PhCH2Cl, again induced C-C coupling to form a bimetallic bis(imino)pyridine cobalt chloride product but also yielded a monomeric cobalt chloride product where the benzyl group added to the enamide carbon. Similar cooperative metal-ligand addition was observed upon treatment of ((iPr)PIEA)CoN2 with CH2âCHCH2Br, which resulted in allylation of the enamide carbon. Reduction of Coupled-((iPr)PDI)CoCl (Coupled-((iPr)PDI)CoCl = [2-(2,6-(i)Pr2-C6H3NâCMe)-C5H3N-6-(2,6-(i)Pr2-C6H3NâCCH2-)CoCl]2) with NaBEt3H led to quantitative formation of ((iPr)PIEA)CoN2, demonstrating the reversibility of the C-C bond forming reactions. The electronic structures of each of the bimetallic cobalt products were also elucidated by a combination of experimental and computational methods.
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Base de dados:
MEDLINE
Assunto principal:
Piridinas
/
Carbono
/
Cobalto
/
Complexos de Coordenação
/
Nitrogênio
Idioma:
En
Ano de publicação:
2013
Tipo de documento:
Article