Chemistry of Iron<i>N</i>-Heterocyclic Carbene Complexes: Syntheses, Structures, Reactivities, and Catalytic Applications

Riener, Korbinian; Haslinger, Stefan; Raba, Andreas; Högerl, Manuel P.; Cokoja, Mirza; Herrmann, Wolfgang A.; Kühn, Fritz E.

doi:10.1021/cr4006439

Cited by 368 publications

(192 citation statements)

References 290 publications

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“…In addition, the stereoelectronic properties of NHCs are easily tuneable by modifying the NHC backbone and the exocyclic nitrogen substituents [7,[21][22][23][24][25][26]. All these beneficial features have popularised the use of NHC ligands in transition metal chemistry [13,14,[27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46]. Among the metals, Group 6 metals (Cr, Mo, W) have played a classical and central role in the development of carbene chemistry.…”

Section: Introductionmentioning

confidence: 99%

N-heterocyclic carbene complexes of Group 6 metals

Wang

Mohamed

et al. 2015

Coordination Chemistry Reviews

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Section: Introductionmentioning

confidence: 99%

N-heterocyclic carbene complexes of Group 6 metals

Wang

Mohamed

et al. 2015

Coordination Chemistry Reviews

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“…[16] We reasoned that the polarizability of the CAAC ligand, by comparison to typical NHCs, [17] might better facilitate N 2 binding and productive functionalization. Note that low-valent Fe-carbene complexes [18] have to date been surprisingly resistant to N 2 binding, with the tripodal, Nheterocyclic carbene (NHC) containing, systems of Meyer [19] and Smith [20] underscoring this point. To our knowledge, a bis(imidazol-2-ylidene)pyridine scaffold is the only Fecarbene derivative where N 2 binding has been established.…”

mentioning

confidence: 99%

Low‐Temperature N₂ Binding to Two‐Coordinate L₂Fe⁰ Enables Reductive Trapping of L₂FeN₂⁻ and NH₃ Generation

Ung

Peters

2014

Angewandte Chemie

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The 2-coordinate (CAAC) 2 Fe complex [CAAC = cyclic (alkyl)(amino)carbene] binds dinitrogen at low temperature (T < −80 °C). The resulting putative 3-coordinate N 2 -complex, (CAAC) 2 Fe(N 2 ), was trapped by one electron reduction to its corresponding anion [(CAAC) 2 FeN 2 ] − at low temperature. This complex was structurally characterized and features an activated dinitrogen unit that can be silylated at the β-nitrogen. KeywordsIron; Nitrogen fixation; Low-coordinate; Carbenes While hundreds of transition-metal-N 2 complexes have been prepared and studied, [1] comparatively few systems afford access to productive N 2 functionalization. [2] This is particularly true for the case of N 2 functionalization by protons and electrons to produce NH 3 (or N 2 H 4 ). Building on extensive early Mo and W model work, [3] Schrock [4] and Nishibayashi [5] have reported Mo-containing coordination complexes (A and B in Figure 1, respectively) that facilitate catalytic N 2 reduction to NH 3 in the presence of suitable acids and reductants. Because Fe is (i) the only transition metal known to be essential to enzymatic nitrogenase function, [6] and (ii) the predominant transition metal catalyst used in the Haber-Bosch ammonia synthesis, [7] studying N 2 reduction chemistry at well-defined Fe model complexes is of interest. [8,9] Recently, our lab demonstrated that Fe coordination complexes (C in Figure 1) are capable of modest catalytic N 2 reduction to NH 3 . [10] ** This work was supported by the N.I.H. (GM 070757) and the Gordon and Betty Moore Foundation. We thank Larry Henling and Michael K. Takase for crystallographic assistance.

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“…However, they show remarkable thermal stability in both the solution phase and solid state. [6] The stability might come from the joint effect of the strongly electrondonating aminocarbenes capability to bind strongly with iron centers [16] and the good p-accepting nature of the chelating vinylsiloxane ligand. To our surprise, while such a combined ligand set has proved useful for creating stable three-coordinate Pt 0 , Pd 0 , and Ni 0 species, the iron analogues have remained elusive until now.…”

Section: Methodsmentioning

confidence: 99%

(Aminocarbene)(Divinyltetramethyldisiloxane)Iron(0) Compounds: A Class of Low‐Coordinate Iron(0) Reagents

et al. 2014

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The combined use of aminocarbene and divinyltetramethyldisiloxane (dvtms) as supporting ligands enables the access of unprecedented low-coordinate iron(0) alkene compounds [L n Fe(h 2 :h 2 -dvtms)] (L = N-heterocyclic carbene (NHC) or cyclic (alkyl)(amino)carbene (CAAC), n = 1 or 2) from the reactions of FeCl 2 with alkali-metal reducing agents, free aminocarbene ligands, and dvtms. The iron(0) species deliver their {L n Fe 0 } fragments to perform redox reactions with Ph 2 SiH 2 , S 8 , Se, and DippN 3 , furnishing novel aminocarbenesupported iron(IV) silylene, all-ferrous iron-sulfur/selenium cubanes, and bis(imido)iron(IV) compounds. These conversions demonstrate the potential synthetic utility of the carbenesupported iron(0) complexes as a valuable class of lowcoordinate iron(0) reagents.

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Chemistry of IronN-Heterocyclic Carbene Complexes: Syntheses, Structures, Reactivities, and Catalytic Applications

Cited by 368 publications

References 290 publications

N-heterocyclic carbene complexes of Group 6 metals

N-heterocyclic carbene complexes of Group 6 metals

Low‐Temperature N₂ Binding to Two‐Coordinate L₂Fe⁰ Enables Reductive Trapping of L₂FeN₂⁻ and NH₃ Generation

(Aminocarbene)(Divinyltetramethyldisiloxane)Iron(0) Compounds: A Class of Low‐Coordinate Iron(0) Reagents

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Chemistry of IronN-Heterocyclic Carbene Complexes: Syntheses, Structures, Reactivities, and Catalytic Applications

Cited by 368 publications

References 290 publications

N-heterocyclic carbene complexes of Group 6 metals

N-heterocyclic carbene complexes of Group 6 metals

Low‐Temperature N2 Binding to Two‐Coordinate L2Fe0 Enables Reductive Trapping of L2FeN2− and NH3 Generation

(Aminocarbene)(Divinyltetramethyldisiloxane)Iron(0) Compounds: A Class of Low‐Coordinate Iron(0) Reagents

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Low‐Temperature N₂ Binding to Two‐Coordinate L₂Fe⁰ Enables Reductive Trapping of L₂FeN₂⁻ and NH₃ Generation