title: Magnetic circular dichroism on the reversible oxygenation of dimethylmesoporphyrin-IX-atopyridinecobalt (II).
abstract: The magnetic circular dichroism spectra were measured for the dimethylmesoporphyrin-IX-atocobalt complexes. As expected dimethylmesoporphyrin-IX-atocobalt (III) and its pyridine complex exhibited the MCD for a typical D4h metalloporphyrins. Dimethylmesoporphyrin-IX-atocobalt (II) and its pyridine complex showed a paramagnetic effect on the MCD especially in the Soret region. A very atypical Soret MCD for the oxygenated dimethylmesoporphyrin-IX-atopyridinecobalt (II) was attributed to the existence of a CT band associated with oxygen from the similarity to the MCD for oxymyoglobin. Temperature-dependent MCD change for the cobalt (II) oxygen complex revealed the reversible oxygen binding to dimethylmesoporphyrin-IX-atopyridinecobalt (II) with KO2 of 3.2 X 10(-3) in (mmHg)-1 at 228 degrees K.
mesh_terms: D001665:Binding Sites; D002942:Circular Dichroism; D003035:Cobalt; D008280:Magnetics; D008968:Molecular Conformation; D011166:Porphyrins; D011725:Pyridines; D013053:Spectrophotometry; D013056:Spectrophotometry, Ultraviolet
chemical_list: D011166:Porphyrins; D011725:Pyridines; D003035:Cobalt