1213705-96-4Relevant academic research and scientific papers
Oxygenation of cobalt Porphyrinates: Coordination or oxidation?
Li, Jianfeng,Noll, Bruce C.,Oliver, Allen G.,Ferraudi, Guillermo,Lappin, A. Graham,Scheidt, W. Robert
experimental part, p. 2398 - 2406 (2010/05/15)
The X-ray characterization of the five-coordinate picket-fence porphyrin complex, [Co(TpivPP)(2-MeHlm)], is reported. The complex has the displacement of cobalt from the porphyrin plane = 0.15 A, and Co-Nlm = 2.145(3) and (Co-Np)av = 1.979(3) . This five-coordinate complex, in the presence of dioxygen and excess 2methylimidazole, undergoes an unanticipated, photoinitiated atropisomerization of the porphyrin ligand, oxidation of cobalt(ll), and the formation of the neutral cobalt(lll) complex [Co(α,α,β,β-TpivPP)(2-MeHlm)(2-MelirT]. Two distinct examples of this complex have been structurally characterized, and both have structural parameters consistent with cobalt(III). The two new Co(III) porphyrin complexes have axial Co-NIm distances ranging from 1.952 to 1.972 , but which allow for the distinction between imidazole and imidazolate. An interesting intermolecular hydrogen bonding network is observed that leads to infinite helical chains. UV-vis spectroscopic study suggests that [Co(TpivPP)(2MeHIm)(O2)] is an intermediate state for the oxidation reaction and that the atropisomerization process is photocatalyzed. A reaction route is proposed based on the spectroscopic studies. 2010 American Chemical Society.
