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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
2004-2-25
pubmed:abstractText
The novel cobalt corrolazine (Cz) complexes (TBP)(8)CzCoCN (1) and (TBP)(8)CzCo(CCSiPh(3)) (2) have been synthesized and examined in light of the recent intense interest regarding the role of corrole ligands in stabilizing high oxidation states. In the case of 2, the molecular structure has been determined by X-ray crystallography, revealing a short Co[bond]C distance of 1.831(4) A and an intermolecular pi-stacking interaction between Cz ring planes, and this structure has been analyzed in regards to the electronic configuration. By a combination of spectroscopic techniques it has been shown that 1 is best described as a cobalt(III)[bond]pi-cation-radical complex, whereas 2 is likely best represented as the resonance hybrid (Cz)Co(IV)(CCSiPh(3)) <--> (Cz+*)Co(III)(CCSiPh(3)). The reduced cobalt(II) complex, [(TBP)(8)CzCo(II)(py)](-), has been generated in situ and shown to bind dioxygen at low temperature to give [(TBP)(8)CzCo(III)(py)(O(2))](-). For the reduced complex [(TBP)(8)CzCo(II)(py)](-), the EPR spectrum in frozen solution is indicative of a low-spin cobalt(II) complex with a d(z)2 ground state. Exposure of [(TBP)(8)CzCo(II)(py)](-) to O(2) leads to the reversible formation of the cobalt(III)-superoxo complex [(TBP)(8)CzCo(III)(py)(O(2))](-), which has been characterized by EPR spectroscopy. VT-EPR measurements show that the dioxygen adduct is stable up to T approximately 240 K. This work is the first observation, to our knowledge, of O(2) binding to a cobalt(II) corrole.
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Mar
pubmed:issn
0002-7863
pubmed:author
pubmed:issnType
Print
pubmed:day
3
pubmed:volume
126
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2515-25
pubmed:year
2004
pubmed:articleTitle
An example of O2 binding in a cobalt(II) corrole system and high-valent cobalt-cyano and cobalt-alkynyl complexes.
pubmed:affiliation
Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA.
pubmed:publicationType
Journal Article