Ammonia synthesis by photocatalytic hydrogenation of a N2-derived molybdenum nitride

Kim, Sangmin; Park, Yoonsu; Kim, Junho; Pabst, Tyler P.; Chirik, Paul J.

doi:10.1038/s44160-022-00044-1

Cited by 21 publications

(18 citation statements)

References 60 publications

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“…Encouraged by the successful catalytic hydrogenation of TEMPO by 2 , a more challenging substrate was targeted. N–H bond formation was of interest due to its relevance in synthetic cycles for the synthesis of ammonia from its elements. − ,− Azobenzene has been used as a representative substrate to evaluate stoichiometric HAT reactivity of metal hydrides, , but catalytic examples using H 2 as the terminal reductant have not been demonstrated. DFT calculations established a relatively low first N–H BDFE of 48.0 kcal/mol with a higher second N–H BDFE of 61.4 kcal/mol in acetonitrile en route to 1,2-diphenylhydrazine formation (Scheme a).…”

Section: Resultsmentioning

confidence: 99%

“…Among various types of redox-active ligands, pyrimidine-imine (PmIm) ligands were selected (Figure b). These nitrogen-based chelates are neutral but structurally similar to the N,C-type chelates used with the group 9 metal catalysts − with established redox-activity. , In addition, the two nitrogens in the pyridimine ring would maintain nitrogen coordination and prevent rollover cyclometallation in the event of ring dissociation …”

Section: Introductionmentioning

confidence: 98%

“…Transition metal complexes that enable both the activation of H 2 and subsequent hydrogen atom transfer (HAT) have been applied to the synthesis of weak chemical bonds. − Among several types of these complexes, (η 5 -C 5 Me 5 )-supported, piano-stool group 9 metal hydrides with L,X-type chelate ligands, [(η 5 -C 5 Me 5 )M(L,X)H] (M = Rh, Ir; (L,X) = 2-phenylpyridine, benzo[h]quinone), first developed by Norton and coworkers, have shown remarkable activity in the catalytic reduction of various compounds using H 2 as the terminal reductant (Figure a). − Because most HAT processes rely on reagents as hydrogen atom sources that generate stoichiometric quantities of waste, , the use of H 2 as the terminal reductant is preferred for improved atom economy and overall sustainability. One feature of [(η 5 -C 5 Me 5 )M(L,X)H] compounds is the relatively low M–H bond dissociation free energies in the range of 52–61 kcal/mol, ,, which are strong enough to promote the cleavage of H 2 but weak enough to promote subsequent HAT to the desired substrate (Figure a). − These metal hydrides are also sufficiently basic (p K a > 30 in MeCN) , so that deleterious protonation chemistry is suppressed.…”

Section: Introductionmentioning

confidence: 99%

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Catalytic N–H Bond Formation Promoted by a Ruthenium Hydride Complex Bearing a Redox-Active Pyrimidine-Imine Ligand

Kim

Zhong

et al. 2022

J. Am. Chem. Soc.

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The synthesis of a piano-stool ruthenium hydride, [(η 5 -C 5 Me 5 )Ru(PmIm)H] (PmIm = (N-(1,3,5-trimethylphenyl)-1-(pyrimidin-2-yl)ethan-1-imine), for the dual purpose of catalytic dihydrogen activation and subsequent hydrogen atom transfer for the formation of weak chemical bonds is described. The introduction of a neutral, potentially redox-active PmIm supporting ligand was designed to eliminate the possibility of deleterious C(sp 2 )−H reductive coupling and elimination that has been identified as a deactivation pathway with related rhodium and iridium catalysts. Treatment of [(η 5 -C 5 Me 5 )RuCl 2 ] n with one equivalent PmIm ligand in the presence of zinc and sodium methoxide resulted in the isolation of the diruthenium complex, [(η 5 -C 5 Me 5 )Ru(PmIm)] 2 , arising from the C−C bond formation between two PmIm chelates. Addition of H 2 to the ruthenium dimer under both thermal and blue light irradiation conditions furnished the targeted hydride, [(η 5 -C 5 Me 5 )Ru(PmIm)H], which has a relatively weak DFT-calculated Ru−H bond dissociation free energy (BDFE) of 47.9 kcal/mol. Addition of TEMPO to [(η 5 -C 5 Me 5 )Ru(PmIm)H] generated the 17-electron metalloradical, [(η 5 -C 5 Me 5 )Ru(PmIm)], which was characterized by EPR spectroscopy. The C−C bond forming process was reversible as the irradiation of [(η 5 -C 5 Me 5 )Ru(PmIm)] 2 generated [(η 5 -C 5 Me 5 )Ru(PmIm)H] and a piano-stool ruthenium complex containing an enamide ligand derived from H-atom abstraction from the PmIm chelate. Equilibration studies were used to establish an experimental estimate of the effective Ru−H BDFE, and a value of 50.8 kcal/mol was obtained, in agreement with the observed loss of H 2 and the DFT-computed value. The ruthenium hydride was an effective catalyst for the thermal catalytic hydrogenation of TEMPO, acridine, and a cobalt-imido complex and for the selective reduction of azobenzene to diphenylhydrazine, highlighting the role of this complex in catalytic weak bond formation using H 2 as the stoichiometric reductant.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Catalytic N–H Bond Formation Promoted by a Ruthenium Hydride Complex Bearing a Redox-Active Pyrimidine-Imine Ligand

Kim

Zhong

et al. 2022

J. Am. Chem. Soc.

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“…[7] PCET-based strategies will be key to establish efficient, photo-and electro-chemically driven NRR catalysis that does not rely on sacrificial chemical reductants. [8] N 2 splitting also provides a potential entry towards nitrogenous products beyond ammonia. This was demonstrated by several stoichiometric (cyclic) reaction sequences, [5,9] as well as the catalytic formation of trisilylamines and recently triborylamines, [10] directly from N 2 .…”

Section: Introductionmentioning

confidence: 99%

“…competing H 2 evolution [7] . PCET‐based strategies will be key to establish efficient, photo‐ and electrochemically driven NRR catalysis that does not rely on sacrificial chemical reductants [8] …”

Section: Introductionmentioning

confidence: 99%

Photoelectrochemical Conversion of Dinitrogen to Benzonitrile: Selectivity Control by Electrophile‐ versus Proton‐Coupled Electron Transfer

et al. 2022

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Nitride complexes are key species in homogeneous nitrogen fixation to NH 3 via stepwise protoncoupled electron transfer (PCET). In contrast, direct generation of nitrogenous organic products from N 2derived nitrides requires new strategies to enable efficient reductive nitride transfer in the presence of organic electrophiles. We here present a 2-step protocol for the conversion of dinitrogen to benzonitrile. Photoelectrochemical, reductive N 2 splitting produces a rhenium(V) nitride with unfavorable PCET thermochemistry towards ammonia generation. However, Nbenzoylation stabilizes subsequent reduction as a basis for selective nitrogen transfer in the presence of the organic electrophile and Brønsted acid at mild reduction potentials. This work offers a new strategy for photoelectrosynthetic nitrogen fixation beyond ammonia-to yield nitrogenous organic products.

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A Graphdiyne Nanoreactor for Conversion of NO₃⁻ to NH₃ from Wastewater

Zhao,

Chen,

Zheng

et al. 2023

Adv Funct Materials

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The lack of highly active and selective catalysts is a major obstacle to replace traditional Haber–Bosch process for electrocatalytic production of ammonia (NH3) at ambient conditions. A new hollow graphdiyne nanoreactor (GDYNR) is reported to overcome this issue effectively. The GDYNR is synthesized by in situ growth of GDY on the inner and outer surfaces of the cobalt hydroxide sphere to form a high‐performance interface structure. Experimental results demonstrate that the incomplete charge transfer between GDY and cobalt atoms at the interfaces promotes the formation of strong interfacial sp‐C─Co bonds and the transition of monovalent Co(II) to mixed Co(II)/Co(III) phases. These intrinsic characteristics give the GDYNR superior NH3 production performances with the highest NH3 yield rate (YNH3) of 479 830.67 µgNH3 mgcat−1 h−1, Faradaic efficiency (FE) of ≈100% at −0.4 V versus reversible hydrogen electrode, and excellent long‐term stability at room temperatures and ambient pressures, along with no side reactions. In light of characteristics of the unique confined hollow structures and the heterointerface with obvious incomplete charge transfer property, the generation of GDYNR system represents an advanced design concept and preparation technology for the development of catalytic systems with new structures.

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Ammonia synthesis by photocatalytic hydrogenation of a N2-derived molybdenum nitride

Cited by 21 publications

References 60 publications

Catalytic N–H Bond Formation Promoted by a Ruthenium Hydride Complex Bearing a Redox-Active Pyrimidine-Imine Ligand

Catalytic N–H Bond Formation Promoted by a Ruthenium Hydride Complex Bearing a Redox-Active Pyrimidine-Imine Ligand

Photoelectrochemical Conversion of Dinitrogen to Benzonitrile: Selectivity Control by Electrophile‐ versus Proton‐Coupled Electron Transfer

A Graphdiyne Nanoreactor for Conversion of NO₃⁻ to NH₃ from Wastewater

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Ammonia synthesis by photocatalytic hydrogenation of a N2-derived molybdenum nitride

Cited by 21 publications

References 60 publications

Catalytic N–H Bond Formation Promoted by a Ruthenium Hydride Complex Bearing a Redox-Active Pyrimidine-Imine Ligand

Catalytic N–H Bond Formation Promoted by a Ruthenium Hydride Complex Bearing a Redox-Active Pyrimidine-Imine Ligand

Photoelectrochemical Conversion of Dinitrogen to Benzonitrile: Selectivity Control by Electrophile‐ versus Proton‐Coupled Electron Transfer

A Graphdiyne Nanoreactor for Conversion of NO3− to NH3 from Wastewater

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Product

Resources

About

A Graphdiyne Nanoreactor for Conversion of NO₃⁻ to NH₃ from Wastewater