A seven-coordinate iron platform and its oxo and nitrene reactivity

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• 作者：Han Sen Soo^a ; ^c ; Moulay T. Sougrati^d ; Fernande Grandjean^d ; Gary J. Long^e ; ^{glong@mst.edu} ; Christopher J. Chang^a ; ^b ; ^c ; ^{chrischang@berkeley.edu}
• 关键词：Pentagonal bipyramidal ; Seven-coordinate ; High-spin iron ; Mö ; ssbauer spectroscopy ; Oxo and nitrene transfer
• 刊名：Inorganica Chimica Acta
• 出版年：2011
• 出版时间：15 April 2011
• 年：2011
• 卷：369
• 期：1
• 页码：82-91
• 全文大小：1151 K

文摘

We present a new structurally determined seven-coordinate iron platform supported by the tris(2-picolyl)amine ligand 6,6′-(pyridin-2-ylmethylazanediyl)bis(methylene)bis(N-tert-butylpicolinamide) (TPA^2C(O)NHtBu, 3) and its reactivity with oxo and nitrene transfer agents. Oxidation of the pentagonal bipyramidal, seven-coordinate iron(II)–triflate complex [TPA^2C(O)NHtBuFe^II(OTf)][OTf] (4) with PhIO produces the corresponding diiron(III) μ-oxo complex [(TPA^2C(O)NHtBuFe^III)₂(O)][OTf]₄ (5). Mössbauer and magnetic measurements on 5 in the solid-state establish antiferromagnetic coupling between its two Fe(III) centers. Reactions of 4 with the nitrene transfer agents PhINTs (Ts = p-MeC₆H₄SO₂) and PhINNs (Ns = p-NO₂C₆H₄SO₂) provide the corresponding iron(III)-amide congeners [TPA^2C(O)NHtBuFe^III(NHTs)][OTf]₂ (6) and [TPA^2C(O)NHtBuFe^III(NHNs)][OTf]₂ (7), respectively, affording a rare pair of isolable Fe(III)-amide compounds formed from nitrene transfer. By characterizing well-defined products in the crystalline form, derived from atom and group transfer to seven-coordinate iron, the collective data provide a starting point for the exploration of high-valent and metal–ligand multiply bonded species supported by approximate pentagonal-type ligand fields.