119923-93-2Relevant articles and documents
O2 and CO binding to jellyfish type iron(II) porphyrins
Uemori, Yoshio,Kyuno, Eishin
, p. 1690 - 1694 (2008/10/08)
The syntheses of jellyfish type iron(II) porphyrins and their O2 and CO affinities in the presence of an excess axial base (1,2-dimethylimidazole) in toluene are reported, together with the O2 affinities for the corresponding cobalt(II) porphyrins. The O2 affinities for the Co(II) porphyrins decreased with an increase in the steric bulk of the fences appended to the porphyrin plane, on which the axial base binding occurs. On the other hand, the O2 and Co affinities for the Fe(II) porphyrins did not exhibit a trend similar to that observed for the O2 affinities for the Co(II) porphyrins. From the measurements of 1H NMR spectra for both O2 and CO adducts of the Fe(II) porphyrins, the conformations of cavities were significantly different in the Fe(II) porphyrin having pivalamide groups as fences, though the 1H NMR signals of protons in the cavities were similar among the corresponding free-base porphyrins. Thus, steric effects of the cavities are responsible for the reduced O2 and CO affinities of the Fe(II) porphyrin. Electronic paramagnetic resonance (EPR) spectra for the bisligated Fe(III) porphyrins were measured in CDCl3 at 77 K, and the changes in the crystal field parameters are also discussed.
