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| | http://www.darientel.net/media/files/pres.php?supra/shoes=adidas-basketball-shoes-90s Yan deficіencies as a holiday destination there are many did not deter the Zhang family, who travelled 700 km (10 hours on a cramped, sleeper bus) just to take in Yangjialing sights. |
| {{expert-subject|date=December 2010}}
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| [[Image:Ferrate ion.svg|thumb|right|ferrate ion [FeO<sub>4</sub>]<sup>2-</sup>]]
| | For thе oldest member of the Zhang tribe, ɑn 82-year-olɗ whom I call Liwu, the journey was of partіcular significance. Ιt was in Yangjialing where, 75 years ago, China Communist Pɑrty launched the revօlution that brougɦt it to power.. <br>http://bio-tec.net/fckeditor/files/pres.php?supra/shoes=adidas-shoes-9.8 George Cloߋney and I are [http://www.Thefreedictionary.com/competitive competitive] by nature, glad we Ьоth are nominated. Ӎeanwhile, Angelina Jolie lookеd stunning in black. Tina Feƴ in Carolina Herrera ѕaid I am tɦrilled to be wearing it. 15. Say what you [http://ennisjack.com/gallery/files/pres.php?salomon/shoes=adidas-shoes-50 pigalle christian louboutin zeppa] actually think. Yes, tҺis is a tough one sometіmes, but highly effective. http://www.cda-westvoorne.nl/test/tmp/pres.php?salomon/shoes=adidas-shoes-4e<br>Overall the device is pleasant tօ hold аnd feels sturdy in your hand. Tɦe back panel haѕ an aluminium finiѕh where frοnt sports a big scratch resistant 7.0 inch TFT-LCD WVGA with 800 X 480 resolution display screen thаt ѕupports the [http://Photo.net/gallery/tag-search/search?query_string=multi-touch+gestures multi-touch gestures]. It allows users with multi-tasking ability through which you can enjoy multiple windows accessіng in single mobile device. http://www.valdemercy.de/hardcore/files/pres.php?jordan/brands=adidas-shoes-at-kohl%27s<br>Zafar later [http://www.wikipedia.org/wiki/befriended befriended] Ali Alex Adam ѡho was very influential in the Hip-Hop industry. |
| '''High-valent [[iron]]''' commonly denotes compounds and intermediates in which iron is found in a formal [[oxidation state]] > 3 that show a [[Valence (chemistry)|number of bonds]] > 6 with a [[coordination number]] ≤ 6. The term is rather uncommon for hepta-coordinate compounds of iron.<ref>Craig et al. Dalton Trans., 2010, 39, 4874-4881 {{DOI|10.1039/B927032A}}</ref> It has to be distinguished from the terms [[Hypervalent molecule|hypervalent and hypercoordinate]], as high-valent iron compounds neither necessarily violate the [[18-electron rule]] nor necessarily show coordination numers > 6. The [[ferrate]] ion [FeO<sub>4</sub>]<sup>2-</sup> was the first structure in this class synthesized. The synthetic compounds discussed below contain highly oxidized iron in general, as the concepts are closely related.
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| ==Oxoiron compounds<ref>'''Review''': Que et al.; Journal of Inorganic Biochemistry Volume 100, Issue 4, April 2006, Pages 421-433;{{DOI|10.1016/j.jinorgbio.2006.01.014}}</ref>==
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| Oxoferryl species are commonly proposed as intermediates in [[catalytic cycles]], especially biological systems in which O<sub>2</sub> activation is required. Diatomic oxygen has a high reduction potential (E<sup>0</sup> = 1.23 V), but the first step required to harness this potential is a thermodynamically unfavorable one electron reduction E<sup>0</sup> = -0.16 V. This reduction occurs in nature by the formation of a [[superoxide]] complex in which a reduced metal is oxidized by O<sub>2</sub>. The product of this reaction is a peroxide radical that is more readily reactive. The abundance of these species in nature and the chemistry that is available to them are the reasons why the study of these compounds is important.{{Citation needed|date=December 2010}} A widely applicable method for the generation of high-valent oxoferryl species is the oxidation with [[iodosobenzene]].
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| :<math>\mathrm{(L)Fe^{n} + OIPh \longrightarrow (L)Fe^{n+2}O + IPh}</math> | |
| :<small>symbolic oxidation of an iron compound using [[iodosobenzene]], L denotes the supporting ligand </small>
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| ===Fe(IV)O===
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| [[Image:Fe4TMCSOPF6.png|thumb|120px|right|thiolate-ligated oxoiron(IV)]]
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| Several syntheses of oxoiron(IV) species have been reported. These compounds model biological complexes such as [[cytochrome P450]], [[NO synthase]], and isopenicillin N synthase. Two such reported compounds are thiolate-ligated oxoiron(IV) and cyclam-acetate oxoiron(IV).
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| Thiolate-ligated oxoiron(IV) is formed by the oxidation of a precursor, [Fe<sup>II</sup>(TMCS)](PF<sub>6</sub>) (TMCS = 1-mercaptoethyl-4,8,11-trimethyl-1,4,8,11-tetraza cyclotetradecane), and 3-5 equivalents of H<sub>2</sub>O<sub>2</sub> at -60 ˚C in [[methanol]]. The iron(IV) compound is deep blue in color and shows intense absorption features at 460 nm, 570 nm, 850 nm, and 1050 nm. This species Fe<sup>IV</sup>(=O)(TMCS)+ is stable at -60 ˚C, but decomposition is reported as temperature increases. Compound 2 was identified by [[Mössbauer spectroscopy]], high resolution electrospray ionization mass spectrometry ([[ESI-MS]]), [[x-ray absorption spectroscopy]], x-ray absorption fine structure ([[EXAFS]]), [[UV-visible spectroscopy]] (UV-vis), Fourier transform infrared spectroscopy ([[FT-IR]]), and results were compared to [[density functional theory|DFT-calculations]].<ref>Bukowski, M. R., Koehntop, K. D., Stubna, A., Bominaar E. L., Halfen, J. A., Munck, E., Nam, W., Que, L., Science, 310, 1000-1002, 2005; {{DOI|10.1126/science.111909}}</ref>
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| [[Image:Fe4TMCOOTf2.png|thumb|120px|right|tetramethylcyclam supported oxoiron(IV)]]
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| [[Cyclam|Tetramethylcyclam]] oxoiron(IV) is formed by the reaction of Fe<sup>II</sup>(TMC)(OTf)<sub>2</sub>, TMC = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane; OTf = CF<sub>3</sub>SO<sub>3</sub>, with iodosylbenzene (PhIO) in CH<sub>3</sub>CN at -40 ˚C. A second method for formation of cyclam oxoiron(IV) is reported as the reaction of Fe<sup>II</sup>(TMC)(OTf)<sub>2</sub> with 3 equivalents of H<sub>2</sub>O<sub>2</sub> for 3 hours. This species is pale green in color and has an absorption maximum at 820 nm. It is reported to be stable for at least 1 month at -40 ˚C. It has been characterized by Mössbauer spectroscopy, ESI-MS, EXAFS, UV-vis, [[Raman Spectroscopy]], and FT-IR.<ref>Rohde, J.-U., In, J.-H., Lim, M. H., Brennessel, W. W., Bikowski, M. R., Stubna, A., Munck, E., Name, W., Que, L., Science, 299, 1037-1039, 2003; {{DOI|10.1126/science.299.5609.1037}}</ref>
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| High-valent iron [[bispidine]] complexes are able to oxidize [[cyclohexane]] to [[cyclohexanol]] and [[cyclohexanone]] in 35% yield with an alcohol to ketone ratio up to 4.<ref>Comba, P. et al.; Inorg. Chem., 2009, 48 (21), pp 10389–10396; {{DOI|10.1021/ic901702s}}</ref>
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| ===Fe(V)O===
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| Fe<sup>V</sup>TAML(=O), [[TAML]] = tetraamido macrocyclic ligand, is formed by the reaction of [Fe<sup>III</sup>(TAML)(H<sub>2</sub>O)](PPh<sub>4</sub>) with 2-5 equivalents of meta-chloroperbenzoic acid at -60 ˚C in n-butyronitrile. This compound has a deep green color with absorption maxima at 445 and 630 nm. It is reported to be stable for at least 1 month at 77 K. Fe<sup>V</sup>TAML(=O) was characterized with electron paramagnetic resonance (EPR), Mössbauer, EXAFS, ESI-MS, reactivity studies, and DFT calculations. This compound is capable of 1 electron oxidation at the metal as opposed to at the ligand. This is due to the stronger –donor capacity of deprotonated amide nitrogens on TAML.<ref>Oliveira, F. T., Chanda, A., Banerjee, D., Shan, X., Mondal, S., Que, L., Bominaar, E. L., Munck, E., Collins, T. J., Science, 315, 835-838, 2007; {{DOI| 10.1126/science.1133417}}</ref>
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| ===Electronic structure===
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| The electronic structure of porphyrin oxoiron compounds has been reviewed.<ref>'''Review''': Fujii, H.; Coordination Chemistry Reviews Volume 226, Issues 1-2, March 2002, Pages 51-60; {{DOI|10.1016/S0010-8545(01)00441-6}}</ref>
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| ==Nitridoiron<ref>'''Review''': Berry, J.F.; Comments on Inorganic Chemistry, 30: 28–66, 2009; {{DOI|10.1080/02603590902768875}}</ref> & imidoiron<ref>'''Review''': Peters, J.C., Mehn, M.P.; Journal of Inorganic Biochemistry Volume 100, Issue 4, April 2006, Pages 634-643; {{doi|10.1016/j.jinorgbio.2006.01.023}}</ref> compounds==
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| [[Image:wieghardt.png|thumb|240px|right|generation of an nitridoiron(VI) complex]]
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| [[Transition metal nitrido complex|Nitrido-]] and imidoiron-compounds are closely related to [[Haber process|iron-dinitrogen chemistry]].<ref>'''Review:''' Tyler, D. R., Crossland, J. E.; Coordination Chemistry Reviews 254 (2010) 1883–1894; {{DOI|10.1016/j.ccr.2010.01.005}}</ref> The biological significance of nitridoiron(V) porphyrins has been reviewed<ref>'''Review''': Nakamoto, K.; Coordination Chemistry Reviews
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| Volume 226, Issues 1-2, March 2002, Pages 153-165; {{DOI|10.1016/S0010-8545(01)00425-8}}</ref><sup>,</sup>.<ref>'''Review''': Nakamoto, K.; Journal of Molecular Structure Volumes 408-409, 1 June 1997, Pages 11-16; {{DOI|10.1016/S0022-2860(96)09670-6}}</ref> A widely applicable method to generate high-valent nitridoiron species is the thermal or photochemical oxidative elimination of molecular nitrogen from an azide complex.
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| :<math>\mathrm{(L)Fe^{n}N_{3} \longrightarrow (L)Fe^{n+2}N + N_{2}}</math>
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| :<small>symbolic oxidative elimination of nitrogen yields a nitridoiron complex, L denotes the supporting ligand </small>
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| ===Fe(IV)N===
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| Several structurally characterized nitridoiron(IV)-compounds exist <ref>Peters, Jonas C.; Que, Lawrence, Jr. et al.; Inorg. Chem., 2007, 46 (14), pp 5720–5726; {{DOI|10.1021/ic700818q}}</ref><sup>,</sup><ref>Smith et al.; Angewandte Chemie International Edition Volume 48, Issue 17, pages 3158–3160, April 14, 2009; {{DOI|10.1002/anie.200900381}}</ref><sup>,</sup>.<ref>Meyer et al.; Angewandte Chemie International Edition Volume 47, Issue 14, pages 2681–2684, March 25, 2008, April 14, 2009; {{DOI|10.1002/anie.200800600}}</ref>
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| ===Fe(V)N===
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| The first nitridoiron(V)-compound was generated and characterized in 1988/1989 by Wagner and Nakamoto using [[photolysis]] and [[Raman spectroscopy]] at low temperatures <ref>Wagner, W.D.; Nakamoto, K.; J. Am. Chem. Soc., 1989, 111 (5), pp 1590–1598; {{DOI|10.1021/ja00187a010}}</ref><sup>,</sup>.<ref>Wagner, W.D.; Nakamoto, K.; J. Am. Chem. Soc., 1988, 110 (12), pp 4044–4045; {{DOI|10.1021/ja00220a057}}</ref>
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| ===Fe(VI)N===
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| A second Fe<sup>VI</sup> species apart from the [[ferrate]] ion, [(Me<sub>3</sub>cy-ac)FeN](PF<sub>6</sub>)<sub>2</sub>, has been reported. This species, is formed by oxidation followed by [[photolysis]] to yield the Fe(VI) species. Characterization of the Fe(VI) complex was done by Mossbauer, EXAFS, IR, and DFT calculations. Unlike the ferrate ion compound 5 is [[diamagnetic]].<ref>Berry, J. F., Bill, E., Bothe, E., George, S. D., Miener, B., Neese, F., Wieghardt, K., Science, 312, 1937-1941, 2006; {{DOI|10.1126/science.1128506}}</ref>
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| ===µ-nitrido compounds & oxidation catalysis<ref>Review: Que, L., Tolman, W.B.; Nature 455, 333-340 (18 September 2008); {{DOI|10.1038/nature07371}}</ref>===
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| Bridged µ-nitrido di-iron [[phthalocyanine]] compounds catalyze the oxidation of [[methane]] to [[methanol]], [[formaldehyde]] and [[formic acid]] using [[hydrogen peroxide]] as sacrificial oxidant.<ref>Sorokin, A.B.; Kudrik, E.V.; Bouchu, D.; Chem. Commun., 2008, 2562-2564; {{DOI|10.1039/B804405H}}</ref>
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| ===Electronic structure===
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| Nitridoiron(IV/V)-species were first explored theoretically in 2002.<ref>Dey, A.; Ghosh, A.; J. Am. Chem. Soc., 2002, 124 (13), pp 3206–3207; {{DOI|10.1021/ja012402s}}</ref>
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| ==References==
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| <references/>
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| ==Further reading==
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| * high-valent manganese: [[Jacobsen's catalyst]]
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| See also:
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| Solomon et al.; Angewandte Chemie International Edition Volume 47, Issue 47, pages 9071–9074, November 10, 2008; {{DOI|10.1002/anie.200803740}}
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| {{DEFAULTSORT:High-Valent Iron}}
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| [[Category:Iron]]
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