Iron -nitrido

High-valent iron also occurs in -nitrido bridged dimers with linear [Fe °-N=Fe" ]" and [Fe =N=Fe ] " cores [209, 210] (and references therein). Such compounds have been prepared first by thermolysis [247] or photolysis [248] of iron(III)-porphyrin complexes with an azide ligand, (N3). Mixed-valent iron-nitrido porphyrin dimers exhibit valence delocalization as can be inferred from the... 

Basic ligand-field considerations predict the following energetic order of valence (i-orbitals for six-coordinate iron-nitrido compounds with approximate 4 sym-... 

Scheme 53 Heterolytic cleavage of Ha at a low-coordinate iron nitrido compound...

PhBP 3)Fe 2(p-N)] (202), respectively, are not derived from N2 cleavage, but they represent the only examples of molecular iron nitridos known so far, that react with Fl2 (Scheme 53). Under mild conditions (ambient temperature, H2 (1 atm)) is heterolyticaUy cleaved to form... 

As already mentioned in Section 1.2, ion/molecule reactions of species having metal-nitrogen bonds with hydrocarbons give rise to the formation of C-N bonds. In this chapter, this topic will be pursued in a more systematic way, and we will commence with a discussion of a high-valent iron-nitrido dication. This field of iron chemistry has gained quite some interest over the last decade [19] as a result of their role in metallo enzymatic transformations [20]. 

Scheme 1.2 Intra- and intennolecular C-N bond fbnnation involving a high-valent iron-nitrido dication. (Adapted from Ref. [3g]. Copyright WILEY-VCH, 2012.)...

Iron centers that are more electron-deficient than iron(III) compounds are used for efficient and highly specific oxidation reactions in, for example, heme and nonheme enzymes [166-172]. Most iron(IV)-complexes found in biological reaction cycles possess terminal or bridging 0x0 groups as is known from a large number of structural and spectroscopic investigations. With the exception of iron(IV)-nitrido groups, nonoxo iron(IV) centers very rarely take part in such reactions. 

A t)tpical feature of the Mossbauer spectra of five- or six-coordinate iron(IV) with an axial oxo group (or a OCH3, a nitrido or a imido group) is a low isomer shift (+0.1 0.15 mm s ), a large and positive quadrupole splitting (1-2 mm s ), an anisotropic hyperfine coupling tensor with moderately large values for A x/gNl N and (—16 to —23 T) and a rather small value for A Jg i (0 to —10 T)... 

FeF602PCuHi3, Iron(l +), ( -cyclopenta-dienyl)dicarbonyl(tetrahydrofuran)-hexafluorophosphate(l-), 26 232 FeMoNO,P2C45H3 Molybdate(l -), hy-drido-nonacarbonyliron-li-nitrido-bis(triphenylphosphorus)-(1+), 26 338... 

The nitrido clusters [Fe4(CO)12N] and Fe4(CO)n(NO)N undergo substitution reactions yielding mono- and disubstituted products.359 The phosphines used (PPh3 and PMe2Ph) preferred to bond to the wingtip irons in the metal butterfly. 

Petrenko T, DeBeer George S, Aliaga-Alcalde N, et al. Characterization of a genuine iron (V)-nitrido species by nuclear resonant vibrational spectroscopy coupled to density functional calculations. J Am Chem Soc. 2007 129 11053-60. 

Various porphyrin compounds such as NFevOEP are known.62 The i Fe=N) stretching frequency of 853 cm-1 is lower than that of the Cr and Mn analogues the nitrido Fev complex is stable only at very low temperature ( 30 K). It is widely accepted that one of the intermediate species in the catalytic cycle of cytochrome P-450 (see later) contains pentavalent iron. The reduction of an R3CFev moiety is an accepted part of the mechanism of dismutation of hydrogen peroxide to water and oxygen catalyzed by catalase. 

More recent work with nitrido clusters within the iron triad revealed chemical shifts in the expected region. For instance, [Ru6N(CO),6] appears at 538 ppm (NH4 ) 91) which can be compared to the carbon resonance of [Ru6C(CO),6] which is at 461.2 ppm (CH4) 112). Although the value is not twice as large as it is at least larger than the carbon resonance. Of the approximately 15 compounds measured, a range from —450 to —620 ppm is observed. Because many of the compounds are closely related some useful trends have appeared. 

FeH, mTI, Iron titanium hydride, 22 90 FeNOisPjRujCflHsi, Ruthenate(l-), trideca-carbonylhydridoirontri-, p-nitrido-bis(triphenylphosphorus)(l +), 21 60 FeN204P2C H3o, Ferrate(l-), tricarbonylni-trosyl-, p.-nitrido-bis(triphenylphos-phorus)(l +), 22 163, 165 FeN20,C,oH,5 HjO, Iron(III), aqua([(l,2-... 

P2FeO3C3 H30, Iron, tricarbonylbis(triphenyl-phosphine)-, 25 154 P2HNO, Os3C47H3o, Osmate(l-), (x-car-bonyl-decarbonyl-(x-hydrido-tri-(x-nitrido-bis(triphenyIphosphorus)(l +), 25 193... 

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