A Seven-Coordinate Iron Platform and its Oxo and Nitrene Reactivity

Abstract

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 [TPA2C(O)NH tBuFeII(OTf)][OTf] (4) with PhIO produces the corresponding diiron(III) -oxo complex [(TPA2C(O)NH tBuFeIII)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-MeC6H4SO 2) and PhINNs (Ns = p-NO2C6H4SO 2) provide the corresponding iron(III)-amide congeners [TPA 2C(O)NHtBuFeIII(NHTs)][OTf] 2 (6) and [TPA2C(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.

Department(s)

Chemistry

Keywords and Phrases

High-spin Iron; Mössbauer Spectroscopy; Oxo And Nitrene Transfer; Pentagonal Bipyramidal; Seven-coordinate

International Standard Serial Number (ISSN)

0020-1693

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2011 Elsevier, All rights reserved.

Publication Date

01 Apr 2011

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