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Solvent Role on Cobalt(II) Dioxygen Carriers Based on Simple Polyamine Ligands
Author(s) -
Del Piero Silvia,
Ghezzi Lisa,
Melchior Andrea,
Tiné Maria Rosaria,
Tolazzi Marilena
Publication year - 2005
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200590062
Subject(s) - chemistry , aqueous solution , reactivity (psychology) , dimethyl sulfoxide , solvent , cobalt , medicinal chemistry , diamine , ligand (biochemistry) , diethylenetriamine , adduct , polyamine , sulfoxide , stoichiometry , acetonitrile , inorganic chemistry , polymer chemistry , organic chemistry , medicine , biochemistry , alternative medicine , receptor , pathology
The kinetics and thermodynamics of O 2 addition to Co II complexes containing the simple triamine ligand (L) diethylenetriamine (= N ‐(2‐aminoethyl)ethane‐1,2‐diamine; dien) or N , N″ ‐dimethyldiethylenetriamine (= N ‐methyl‐ N′ ‐[2‐(methylamino)ethyl]ethane‐1,2‐diamine; dmdien) in the aprotic solvent dimethyl sulfoxide (DMSO) were studied by UV/VIS spectrophotometry, potentiometry, and O 2 absorption measurements. A parallel investigation on the anaerobic formation of Co II complexes with dmdien, as well as on their reactivity towards O 2 , was carried out in aqueous 0.1 M NaClO 4 solution. [CoL] 2+ and [CoL 2 ] 2+ were the common species formed under anaerobic conditions in both aqueous and DMSO solutions. Under aerobic conditions, O 2 adducts of different stoichiometry were formed: a superoxo complex [CoL 2 O 2 ] 2+ in DMSO and dimeric species in H 2 O. The role of the reaction medium as well as effects of N ‐alkylation of the triamine ligand in the formation and reactivity of the [Co II (triamine)] complexes are discussed.