NMR studies on the electronic structure of one-electron oxidized complexes of iron(III) porphyrinates

✍ Scribed by Akira Ikezaki; Yoshiki Ohgo; Mikio Nakamura

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 992 KB
• Volume: 253
• Category: Article
• ISSN: 0010-8545
• DOI: 10.1016/j.ccr.2009.01.003

✦ Synopsis

This review describes the relationship between the NMR chemical shifts and electronic structures of oneelectron oxidized products of iron(III) porphyrins such as iron(III) porphyrin radical cations or iron(IV) porphyrins. In the case of the former complexes, the iron(III) ions are classified into four types; (i) highspin (S = 5/2), (ii) mixed high-and intermediate-spin (S = 5/2, 3/2), (iii) low-spin with the (d xy ) 2 (d xz , d yz ) 3 ground state, and (iv) low-spin with the (d xz , d yz ) 4 (d xy ) 1 ground state. In the case of the latter complexes, they mostly have Fe IV O bonds. There is only one iron(IV) complex that has no Fe IV O bond. The complexes classified as above exhibit unique NMR chemical shifts. Thus, the NMR spectroscopy serves a quite useful tool to determine the fine electronic structures of the one-electron oxidized iron(III) porphyrin complexes.