Molecular Recognition in the Oxidation of Catechols by Dicobalt-BISDIEN Dioxygen Complexes
Abstract
Formation and degradation of molecular species of the substrate- receptor complex (mu-4 methylcatechol)-mu-peroxodicobalt(III)-BISDIEN were studied by UV-vis spectroscopy. The family of absorbance curves show an intense charge transfer band with a maximum at 367 nm. The degradation redox reaction showed first order behavior. The reactive intermediate has a peroxo bridge and a bridging substrate, 4-methylcatechol coordinated to the two metal centers in the macrocyclic cavity. In the presence of excess substrate and dioxygen, the reaction is catalytic and the product is 3-methyl-cis, cis-muconic acid, which was separated by HPLC and characterized by mass spectrometry. When 3,5-di-t- butylcatechol was used in place of 4-methylcatechol the redox reaction was not observed. This substrate cannot coordinate to the bimetallic center in the cavity of BISDIEN, and is not oxidized. The results are discussed on the basis of the selectivity of the receptor complex.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 30, 1992
- Accession Number
- ADA246456
Entities
People
- Arthur E. Martell
- Bruno Szpoganicz
- F. S. Cezar
Organizations
- Texas A&M University