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Solari, Euro; Silva, Carlos Da; Iacono, Barbara; Hesschenbrouck, Joëlle; Rizzoli, Corrado; Scopelliti, Rosario; Floriani, Carlo

doi:10.1002/1521-3757(20011015)113:20<4025::aid-ange4025>3.3.co;2-x

Cited by 14 publications

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“…Meanwhile, advanced catalysts have been investigated to extend beyond electrochemical systems including biochemical, biomimetic metal complex, electride, and photochemical systems . Among them, biomimetic metal complexes, which are also referred to as molecular catalysts, composed of metal‐atom (such as Mo, Fe, and Zr) cores and various types of pincer ligands have demonstrated great potential as efficient catalysts for the NRR. The investigation on these molecular catalysts also facilitates the understanding of the NRR mechanism in more complex biological systems such as nitrogenase .…”

Section: Introductionmentioning

confidence: 99%

Recent Advanced Materials for Electrochemical and Photoelectrochemical Synthesis of Ammonia from Dinitrogen: One Step Closer to a Sustainable Energy Future

Yan

Xia

et al. 2019

Advanced Energy Materials

133

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Ammonia (NH3), an important raw material for chemical industry and agriculture, is also considered to be an intriguing energy storage and transportation media for chemical conversion schemes. The world's primary NH3 supply is based on the natural nitrogen fixation by diazotrophs through an enzymatic nitrogenase process and the industrial nitrogen fixation through a traditional Haber–Bosch process. The natural synthesis of NH3 can hardly meet the rapidly growing global demand. Meanwhile, the industrial NH3 production is still dominated by the high‐temperature and high‐pressure reaction between nitrogen and hydrogen (N2 + 3H2 → 2NH3), requiring intensive energy input and generating massive CO2. Therefore, seeking a breakthrough in the development of catalysts toward efficient ammonia synthesis has become the frontier of energy and chemical conversion schemes. This review summarizes and discusses the recent progress on developing new strategies to optimize the efficiency of NH3 production coupled with renewable energy sources, with a specific focus on electrocatalytic and photoelectrocatalytic conversion of N2 to NH3. The most recent advances in the development of catalytic materials, the design of the reaction systems, and the computational insights for electrochemical and photoelectrochemical ammonia synthesis are covered.

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Section: Introductionmentioning

confidence: 99%

Recent Advanced Materials for Electrochemical and Photoelectrochemical Synthesis of Ammonia from Dinitrogen: One Step Closer to a Sustainable Energy Future

Yan

Xia

et al. 2019

Advanced Energy Materials

133

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“…Floriani and co-workers concluded that cleavage of the nitrogen bond was the initial step in the photochemical reaction of thermally stable (μ-N 2 )[Mo(Mes) 3 ] 2 (Mes = 2,4,6-Me 3 C 6 H 2 ) based on conversion to (Mes) 3 Mo−N−Mo(Mes) 3 under UV illumination. 13 Using ultraviolet excitation, Kunkely and Volger recently demonstrated dissociation of the nitrogen bond in a μ-N 2 diosmium cation. 16 In the longest wavelength activation reported, Curley 3 ] 2 leads to breaking of both NN and Mo−NN bonds with roughly equal branching.…”

Section: ■ Introductionmentioning

confidence: 99%

Relaxation and Dissociation Following Photoexcitation of the (μ-N₂)[Mo(N[t-Bu]Ar)₃]₂ Dinitrogen Cleavage Intermediate

et al. 2013

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Frequency resolved pump-probe spectroscopy was performed on isolated (μ-N(2))[Mo(N[t-Bu]Ar)(3)](2) (Ar = 3,5-C(6)H(3)Me(2)), an intermediate formed in the reaction of Mo(N[t-Bu]Ar)(3) to bind and cleave dinitrogen. Evidence is presented for 300 fs internal conversion followed by subpicosecond vibrational cooling on the ground electronic state in competition with bond dissociation. Fast cooling following photoexcitation leads to a relatively low overall dissociation yield of 5%, in quantitative agreement with previous work [Curley, J. J.; Cooke, T. R.; Reece, S. Y.; Mueller, P.; Cummins, C. C. J. Am. Chem. Soc. 2008, 130, 9394]. Coupling of vibrational modes to the excitation and internal conversion results in a nonthermal distribution of energy following conversion, and this provides sufficient bias to allow the nitrogen cleavage reaction to compete with breaking of the Mo-NN bond despite a higher energetic barrier on the ground state.

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“…This is why "reagents and pathways for breaking into chemical bonds previously considered to be inert," and "means for converting naturally abundant substances into chemically useful building blocks," find a nexus on the wish list of grand challenges envisioned by today's chemists. 1,2 In the case of dinitrogen, several reactions in which soluble transition-metal complexes bind the N 2 molecule and effect complete scission of its 226 kcal/mol triple bond to give nitride (N 3-, alternatively "nitrido") systems now are recognized for molybdenum, [3][4][5][6][7][8][9] niobium, [10][11][12] and vanadium. 13 Dinitrogen cleavage reactions have frequently been the subject of theoretical studies.…”

Section: Introductionmentioning

confidence: 99%

A Nitridoniobium(V) Reagent That Effects Acid Chloride to Organic Nitrile Conversion: Synthesis via Heterodinuclear (Nb/Mo) Dinitrogen Cleavage, Mechanistic Insights, and Recycling

et al. 2005

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The transformation of acid chlorides (RC(O)Cl) to organic nitriles (RC[triple bond]N) by the terminal niobium nitride anion [N[triple bond]Nb(N[Np]Ar)3]- ([1a-N]-, where Np = neopentyl and Ar = 3,5-Me2C6H3) via isovalent N for O(Cl) metathetical exchange is presented. Nitrido anion [1a-N]- is obtained in a heterodinuclear N2 scission reaction employing the molybdenum trisamide system, Mo(N[R]Ar)3 (R = t-Bu, 2a; R = Np, 2b), as a reaction partner. Reductive scission of the heterodinuclear bridging N2 complexes, (Ar[R]N)3Mo-(mu-N2)Nb(N[Np]Ar)3 (R = t-Bu, 3b; R = Np, 3c) with sodium amalgam provides 1 equiv each of the salt Na[1a-N] and neutral N[triple bond]Mo(N[R]Ar)3 (R = t-Bu, 2a-N; R = Np, 2b-N). Separation of 2-N from Na[1a-N] is readily achieved. Treatment of salt Na[1a-N] with acid chloride substrates in tetrahydrofuran (THF) furnishes the corresponding organic nitriles concomitant with the formation of NaCl and the oxo niobium complex O[triple bond]Nb(N[Np]Ar)3 (1a-O). Utilization of 15N-labeled 15N2 gas in this chemistry affords a series of 15N-labeled organic nitriles establishing the utility of anion [1a-N]- as a reagent for the 15N-labeling of organic molecules. Synthetic and computational studies on model niobium systems provide evidence for the intermediacy of both a linear acylimido and niobacyclobutene species along the pathway to organic nitrile formation. High-yield recycling of oxo 1a-O to a niobium triflate complex appropriate for heterodinuclear N2 scission has been developed. Specifically, addition of triflic anhydride (Tf2O, where Tf = SO2CF3) to an Et2O solution of 1a-O provides the bistriflate complex, Nb(OTf)2(N[Np]Ar)3 (1a-(OTf)2), in near quantitative yield. One-electron reduction of 1a-(OTf)2 with either cobaltocene (Cp2Co) or Mg(THF)3(anthracene) provided the monotriflato complex, Nb(OTf)(N[Np]Ar)3 (1a-(OTf)), which efficiently regenerates complexes 3b and 3c when treated with the molybdenum dinitrogen anions [N2Mo(N[t-Bu]Ar)3]- ([2a-N2]-) or [N2Mo(N[Np]Ar)3]- ([2b-N2]-), respectively.

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Cited by 14 publications

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Recent Advanced Materials for Electrochemical and Photoelectrochemical Synthesis of Ammonia from Dinitrogen: One Step Closer to a Sustainable Energy Future

Recent Advanced Materials for Electrochemical and Photoelectrochemical Synthesis of Ammonia from Dinitrogen: One Step Closer to a Sustainable Energy Future

Relaxation and Dissociation Following Photoexcitation of the (μ-N₂)[Mo(N[t-Bu]Ar)₃]₂ Dinitrogen Cleavage Intermediate

A Nitridoniobium(V) Reagent That Effects Acid Chloride to Organic Nitrile Conversion: Synthesis via Heterodinuclear (Nb/Mo) Dinitrogen Cleavage, Mechanistic Insights, and Recycling

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Cited by 14 publications

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Recent Advanced Materials for Electrochemical and Photoelectrochemical Synthesis of Ammonia from Dinitrogen: One Step Closer to a Sustainable Energy Future

Recent Advanced Materials for Electrochemical and Photoelectrochemical Synthesis of Ammonia from Dinitrogen: One Step Closer to a Sustainable Energy Future

Relaxation and Dissociation Following Photoexcitation of the (μ-N2)[Mo(N[t-Bu]Ar)3]2 Dinitrogen Cleavage Intermediate

A Nitridoniobium(V) Reagent That Effects Acid Chloride to Organic Nitrile Conversion: Synthesis via Heterodinuclear (Nb/Mo) Dinitrogen Cleavage, Mechanistic Insights, and Recycling

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Relaxation and Dissociation Following Photoexcitation of the (μ-N₂)[Mo(N[t-Bu]Ar)₃]₂ Dinitrogen Cleavage Intermediate