1
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Liu L, Johnson SI, Appel AM, Bullock RM. Oxidation of Ammonia Catalyzed by a Molecular Iron Complex: Translating Chemical Catalysis to Mediated Electrocatalysis. Angew Chem Int Ed Engl 2024; 63:e202402635. [PMID: 38981858 DOI: 10.1002/anie.202402635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 07/08/2024] [Accepted: 07/09/2024] [Indexed: 07/11/2024]
Abstract
Ammonia is a promising candidate in the quest for sustainable, clean energy. With its capacity to serve as an energy carrier, the oxidation of ammonia opens avenues for carbon-neutral approaches to address worldwide growing energy needs. We report the catalytic chemical oxidation of ammonia by an Earth-abundant transition metal complex, trans-[LFeII(MeCN)2][PF6]2, where L is a macrocyclic ligand bearing four N-heterocyclic carbene (NHC) donors. Using triarylaminium radical cations in MeCN, up to 182 turnovers of N2 per Fe were obtained from chemical catalysis with an extremely low loading of the Fe catalyst (0.043 mM, 0.004 mol % catalyst). This chemical catalysis was successfully transitioned to mediated electrocatalysis for the oxidation of ammonia. Molecular electrocatalysis by the Fe catalyst and the mediator (p-MeOC6H4)3N exhibited a catalytic half-wave potential (Ecat/2) of 0.18 V vs [Cp2Fe]+/0 in MeCN, and achieved 9.3 turnovers of N2 at an applied potential of 0.20 V vs [Cp2Fe]+/0 at -20 °C in controlled-potential electrolysis, with a Faradaic efficiency of 75 %. Based on computational results, the catalyst undergoes sequential oxidation and deprotonation steps to form [LFeIV(NH2)2]2+, and thereafter bimetallic coupling to form an N-N bond.
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Affiliation(s)
- Liang Liu
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington, 99352, USA
- Current address: College of Chemistry, Central China Normal University, Wuhan, Hubei, 430079, P. R. China
| | - Samantha I Johnson
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington, 99352, USA
| | - Aaron M Appel
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington, 99352, USA
| | - R Morris Bullock
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington, 99352, USA
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2
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Gao W, Wu Q, Fan X, Lu N, Liu Y, Quan X. Promoting Electrocatalytic Reduction of CO 2 and Nitrate to Urea on N-Doped Porous Hollow Carbon Spheres. ACS APPLIED MATERIALS & INTERFACES 2024; 16:50726-50735. [PMID: 39265150 DOI: 10.1021/acsami.4c09949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/14/2024]
Abstract
The electrocatalytic coreduction of CO2 and nitrate is a green method for urea synthesis, mitigating CO2 emission and nitrate contamination. However, its slow kinetics and high energy barrier result in a poor urea production performance. Herein, we reported N-doped porous hollow carbon spheres (N-PHCS) for promoting CO2 and nitrate conversion to urea via nanoconfinement and N-doping from both reaction kinetics and thermodynamics. A high urea yield of 12.0 mmol h-1 gcat-1 with Faradaic efficiency of 19.1% was achieved on N-PHCS at -1.0 V (vs Ag/AgCl), which was comparable to or even higher than those of metal-based electrocatalysts reported. The experimental and theoretical calculation results revealed that carbon spheres with an appropriate interior void and pore size were favorable for confining reactants and intermediates to accelerate urea production, while N-doping can reduce the energy barrier for urea synthesis. By regulating the microstructure and N doping of N-PHCS, it showed a superior performance for urea electrosynthesis. The energy favorable pathway for urea synthesis was through the C-N coupling reaction of *NO and *CO, and pyridinic N can reduce the reaction energy barrier.
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Affiliation(s)
- Wantao Gao
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Qinyue Wu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Xinfei Fan
- College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026, China
| | - Na Lu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
- School of Electrical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Yanming Liu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Xie Quan
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
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3
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Trenerry MJ, Acosta M, Berry JF. Computational Analysis of Low Overpotential Ammonia Oxidation by Metal-Metal Bonded Ruthenium Catalysts, and Predictions for Related Osmium Catalysts. J Phys Chem A 2024; 128:4038-4051. [PMID: 38742806 DOI: 10.1021/acs.jpca.4c02490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
The catalyzed electrochemical oxidation of ammonia to nitrogen (AOR) is an important fuel-cell half-reaction that underpins a future nitrogen-based energy economy. Our laboratory has reported spontaneous chemical and electrochemical oxidation of ammonia to dinitrogen via reaction of ammonia with the metal-metal bonded diruthenium complex Ru2(chp)4OTf (chp- = 2-chloro-6-hydroxypyridinate, TfO- = trifluoromethanesulfonate). This complex facilitates electrocatalytic ammonia oxidation at mild applied potentials of -255 mV vs ferrocene, which is the [Ru2(chp)4(NH3)]0/+ redox potential. We now report a comprehensive computational investigation of possible mechanisms for this reaction and electronic structure analysis of key intermediates therein. We extend this analysis to proposed second-generation electrocatalysts bearing structurally similar fhp and hmp (2-fluoro-6-hydroxypyridinate and 2-hydroxy-6-methylpyridinate, respectively) equatorial ligands, and we further expand this study from Ru2 to analogous Os2 cores. Predicted M24+/5+ redox potentials, which we expect to correlate with experimental AOR overpotential, depend strongly on the identity of the metal center, and to a lesser degree on the nature of the equatorial supporting ligand. Os2 complexes are easier to oxidize than analogous Ru2 complexes by ∼640 mV, on average. In contrast to mono-Ru catalysts, which oxidize ammonia via a rate-limiting activation of the strong N-H bond, we find lowest-energy reaction pathways for Ru2 and Os2 complexes that involve direct N-N bond formation onto electrophilic intermediates having terminal amido, imido, or nitrido groups. While transition state energies for Os2 complexes are high, those for Ru2 complexes are moderate and notably lower than those for mono-Ru complexes. We attribute these lower barriers to enhanced electrophilicity of the Ru2 intermediates, which is a consequence of their metal-metal bonded structure. Os2 intermediates are found to be, surprisingly, less electrophilic, and we suggest that Os2 complexes may require access to oxidation states higher than Os25+ in order to perform AOR at reasonable reaction rates.
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Affiliation(s)
- Michael J Trenerry
- Department of Chemistry, University of Wisconsin - Madison, Madison, Wisconsin 53706, United States
- Department of Chemistry, University of Minnesota - Twin Cities, Minneapolis, Minnesota 55455, United States
| | - Milton Acosta
- Department of Chemistry, University of Wisconsin - Madison, Madison, Wisconsin 53706, United States
| | - John F Berry
- Department of Chemistry, University of Wisconsin - Madison, Madison, Wisconsin 53706, United States
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4
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Almquist CC, Rajeshkumar T, Jayaweera HDAC, Removski N, Zhou W, Gelfand BS, Maron L, Piers WE. Oxidation-induced ambiphilicity triggers N-N bond formation and dinitrogen release in octahedral terminal molybdenum(v) nitrido complexes. Chem Sci 2024; 15:5152-5162. [PMID: 38577349 PMCID: PMC10988598 DOI: 10.1039/d4sc00090k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 02/16/2024] [Indexed: 04/06/2024] Open
Abstract
Coupling of octahedral, terminal d1 molybdenum(v) nitrido complexes supported by a dianionic pentadentate ligand via N-N bond formation to give μ-dinitrogen complexes was found to be thermodynamically feasible but faces significant kinetic barriers. However, upon oxidation, a kinetically favored nucleophilic/electrophilic N-N bond forming mechanism was enabled to give monocationic μ-dinitrogen dimers. Computational and experimental evidence for this "oxidation-induced ambiphilic nitrido coupling" mechanism is presented. The factors influencing release of dinitrogen from the resulting μ-dinitrogen dimers were also probed and it was found that further oxidation to a dicationic species is required to induce (very rapid) loss of dinitrogen. The mechanistic path discovered for N-N bond formation and dinitrogen release follows an ECECC sequence (E = "electrochemical step"; C = "chemical step"). Experimental evidence for the intermediacy of a highly electrophilic, cationic d0 molybdenum(vi) nitrido in the N-N bond forming mechanism via trapping with an isonitrile reagent is also discussed. Together these results are relevant to the development of molecular catalysts capable of mediating ammonia oxidation to dihydrogen and dinitrogen.
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Affiliation(s)
- C Christopher Almquist
- Department of Chemistry, University of Calgary 2500 University Drive NW Calgary Alberta T2N 1N4 Canada
| | | | - H D A Chathumal Jayaweera
- Department of Chemistry, University of Calgary 2500 University Drive NW Calgary Alberta T2N 1N4 Canada
| | - Nicole Removski
- Department of Chemistry, University of Calgary 2500 University Drive NW Calgary Alberta T2N 1N4 Canada
| | - Wen Zhou
- Department of Chemistry, University of Calgary 2500 University Drive NW Calgary Alberta T2N 1N4 Canada
| | - Benjamin S Gelfand
- Department of Chemistry, University of Calgary 2500 University Drive NW Calgary Alberta T2N 1N4 Canada
| | - Laurent Maron
- LPCNO, Université de Toulouse, INSA UPS Toulouse France
| | - Warren E Piers
- Department of Chemistry, University of Calgary 2500 University Drive NW Calgary Alberta T2N 1N4 Canada
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5
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Phearman AS, Bullock RM. Synthesis and Reactivity of Fe(II) Complexes Containing Cis Ammonia Ligands. Inorg Chem 2024; 63:2024-2033. [PMID: 38230973 DOI: 10.1021/acs.inorgchem.3c03757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
The development of earth-abundant transition-metal complexes for electrocatalytic ammonia oxidation is needed to facilitate a renewable energy economy. Important to this goal is a fundamental understanding of how ammonia binds to complexes as a function of ligand geometry and electronic effects. We report the synthesis and characterization of a series of Fe(II)-NH3 complexes supported by tetradentate, facially binding ligands with a combination of pyridine and N-heterocyclic carbene donors. Electronic modification of the supporting ligand led to significant shifts in the FeIII/II potential and variations in NH bond acidities. Finally, investigations of ammonia oxidation by cyclic voltammetry, controlled potential bulk electrolysis, and through addition of stoichiometric organic radicals, TEMPO and tBu3ArO• are reported. No catalytic oxidation of NH3 to N2 was observed, and 15N2 was detected only in reactions with tBu3ArO•.
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Affiliation(s)
- Alexander S Phearman
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - R Morris Bullock
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
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6
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Roithmeyer H, Sévery L, Moehl T, Spingler B, Blacque O, Fox T, Iannuzzi M, Tilley SD. Electrocatalytic Ammonia Oxidation with a Tailored Molecular Catalyst Heterogenized via Surface Host-Guest Complexation. J Am Chem Soc 2024; 146:430-436. [PMID: 38134360 DOI: 10.1021/jacs.3c09725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2023]
Abstract
Macrocyclic host molecules bound to electrode surfaces enable the complexation of catalytically active guests for molecular heterogeneous catalysis. We present a surface-anchored host-guest complex with the ability to electrochemically oxidize ammonia in both organic and aqueous solutions. With an adamantyl motif as the binding group on the backbone of the molecular catalyst [Ru(bpy-NMe2)(tpada)(Cl)](PF6) (1) (where bpy-NMe2 is 4,4'-bis(dimethylamino)-2,2'-bipyridyl and tpada is 4'-(adamantan-1-yl)-2,2':6',2″-terpyridine), high binding constants with β-cyclodextrin were observed in solution (in DMSO-d6:D2O (7:3), K11 = 492 ± 21 M-1). The strong binding affinities were also transferred to a mesoporous ITO (mITO) surface functionalized with a phosphonated derivative of β-cyclodextrin. The newly designed catalyst (1) was compared to the previously reported naphthyl-substituted catalyst [Ru(bpy-NMe2)(tpnp)(Cl)](PF6) (2) (where tpnp is 4'-(naphthalene-2-yl)-2,2':6',2″-terpyridine) for its stability during catalysis. Despite the insulating nature of the adamantyl substituent serving as the binding group, the stronger binding of this unit to the host-functionalized electrode and the resulting shorter distance between the catalytic active center and the surface led to better performance and higher stability. Both guests are able to oxidize ammonia in both organic and aqueous solutions, and the host-anchored electrode can be refunctionalized multiple times (>3) following the loss of the catalytic activity, without a reduction in performance. Guest 1 exhibits significantly higher stability in comparison to guest 2 toward basic conditions, which often constitutes a challenge for anchored molecular systems. Ammonia oxidation in water led to the selective formation of NO3- with Faradaic efficiencies of up to 100%.
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Affiliation(s)
- Helena Roithmeyer
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland
| | - Laurent Sévery
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland
| | - Thomas Moehl
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland
| | - Bernhard Spingler
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland
| | - Olivier Blacque
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland
| | - Thomas Fox
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland
| | - Marcella Iannuzzi
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland
| | - S David Tilley
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland
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7
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Chen CP, Alharbi W, Cundari TR, Hamann TW, Smith MR. Deciphering the Mechanism of Base-Triggered Conversion of Ammonia to Molecular Nitrogen and Methylamine to Cyanide. J Am Chem Soc 2023; 145:26339-26349. [PMID: 38011890 DOI: 10.1021/jacs.3c09879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
We report an in-depth investigation into the ammonia oxidation mechanism by the catalyst [RuIII(tpy)(dmabpy)NH3]3+ ([Ru(NH3)]3+). Stoichiometric reactions of [Ru(NH3)]3+ were carried out with exogenous noncoordinating bases to trigger a proposed redox disproportionation reaction, which was followed using variable-temperature NMR spectroscopy. An intermediate species was identified as a dinitrogen-bridged complex using 15N NMR and Raman spectroscopy on isotopically labeled complexes. This intermediate is proposed to derive from coupling of nitridyl species formed upon sequential redox disproportion reactions. Acetonitrile displaces the dinitrogen bridge to yield free N2. DFT calculations support this lower-energy pathway versus that previously reported for ammonia oxidation by the parent [RuIII(tpy)(bpy)NH3]3+ complex. These experimental and computational results are consistent with the interpretation of redox disproportionation involving sequential hydrogen atom transfer reactions by an amide/aminyl intermediate, [Ru(NH2)-]+ ⇔ [Ru(NH2)•]+, formed upon deprotonation of the parent complex. Control experiments employing a large excess of ammonia as a base indicate this new proposed lower-energy pathway contributes to the oxidation of ammonia to dinitrogen in conditions relevant to electrocatalysis. In addition, analogous methylamine complexes, [Ru(NH2CH3)]2+/3+, were prepared to further test the proposed mechanism. Treating [Ru(NH2CH3)]3+ with a base cleanly yields two products [Ru(NH2CH3)]2+ and [Ru(CN)]+ in an ∼3:1 ratio, fully consistent with the proposed cascade of hydrogen atom transfer reactions by an intermediate.
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Affiliation(s)
- Chuan-Pin Chen
- Department of Chemistry, Michigan State University, 578 S Shaw Ln, East Lansing, Michigan 48824, United States
| | - Waad Alharbi
- Department of Chemistry, Center of Advanced Scientific Computing and Modeling (CASCaM), University of North Texas, 1155 Union Circle, #305070, Denton, Texas 76203-5017, United States
| | - Thomas R Cundari
- Department of Chemistry, Center of Advanced Scientific Computing and Modeling (CASCaM), University of North Texas, 1155 Union Circle, #305070, Denton, Texas 76203-5017, United States
| | - Thomas W Hamann
- Department of Chemistry, Michigan State University, 578 S Shaw Ln, East Lansing, Michigan 48824, United States
| | - Milton R Smith
- Department of Chemistry, Michigan State University, 578 S Shaw Ln, East Lansing, Michigan 48824, United States
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8
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Stephens DN, Szilagyi RK, Roehling PN, Arulsamy N, Mock MT. Catalytic Ammonia Oxidation to Dinitrogen by a Nickel Complex. Angew Chem Int Ed Engl 2023; 62:e202213462. [PMID: 36279321 DOI: 10.1002/anie.202213462] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Indexed: 11/07/2022]
Abstract
We report a nickel complex for catalytic oxidation of ammonia to dinitrogen under ambient conditions. Using the aryloxyl radical 2,4,6-tri-tert-butylphenoxyl (t Bu3 ArO⋅) as a H atom acceptor to cleave the N-H bond of a coordinated NH3 ligand up to 56 equiv of N2 per Ni center can be generated. Employing the N-oxyl radical 2,2,6,6-(tetramethylpiperidin-1-yl)oxyl (TEMPO⋅) as the H-atom acceptor, up to 15 equiv of N2 per Ni center are formed. A bridging Ni-hydrazine product identified by isotopic nitrogen (15 N) studies and supported by computational models indicates the N-N bond forming step occurs by bimetallic homocoupling of two paramagnetic [Ni]-NH2 fragments. Ni-mediated hydrazine disproportionation to N2 and NH3 completes the catalytic cycle.
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Affiliation(s)
- David N Stephens
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, USA
| | - Robert K Szilagyi
- Department of Chemistry, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Paige N Roehling
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, USA
| | - Navamoney Arulsamy
- Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071, USA
| | - Michael T Mock
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, USA
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9
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Huang XK, Li LP, Zhou HY, Xiong MF, Fan JY, Ye BH. Switching the Photoreactions of Ir(III) Diamine Complexes between C-N Coupling and Dehydrogenation under Visible Light Irradiation. Inorg Chem 2022; 61:20834-20847. [PMID: 36520143 DOI: 10.1021/acs.inorgchem.2c03161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The selective photoreactions under mild conditions play an important role in synthetic chemistry. Herein, efficient and mild protocols for switching the photoreactions of Ir(III)-diamine complexes between the interligand C-N coupling and dehydrogenation are developed in the presence of O2 in EtOH solution. The photoreactions of achiral diamine complexes rac-[Ir(L)2(dm)](PF6) (L is 2-phenylquinoline or 2-(2,4-difluorophenyl)quinoline, dm is 1,2-ethylenediamine, 1,2-diaminopropane, 2-methyl-1,2-diamino-propane, or N,N'-dimethyl-1,2-ethylenediamine) are competitive in the oxidative C-N coupling and dehydrogenation at room temperature, which can be switched into the interligand C-N coupling reaction at 60 °C, affording hexadentate complexes in good to excellent yields, or the dehydrogenative reaction in the presence of a catalytic amount of TEMPO as an additive, affording imine complexes. Mechanism studies reveal that 1O2 is the major reactive oxygen species, and metal aminyl is the key intermediate in the formation of the oxidative C-N coupling and imine products in the photoreaction processes. These will provide a new and practical protocol for the synthesis of multidentate and imine ligands in situ via the postcoordinated strategy under mild conditions.
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Affiliation(s)
- Xiao-Kang Huang
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou 510275 Guangdong, China
| | - Li-Ping Li
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou 510275 Guangdong, China
| | - Hai-Yun Zhou
- Instrumental Analysis and Research Center, Sun Yat-sen University, Guangzhou 510275 Guangdong, China
| | - Ming-Feng Xiong
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou 510275 Guangdong, China
| | - Jing-Yan Fan
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou 510275 Guangdong, China
| | - Bao-Hui Ye
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou 510275 Guangdong, China
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10
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Tanabe Y, Nishibayashi Y. Recent advances in catalytic nitrogen fixation using transition metal–dinitrogen complexes under mild reaction conditions. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2022.214783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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11
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Ahmed ME, Raghibi Boroujeni M, Ghosh P, Greene C, Kundu S, Bertke JA, Warren TH. Electrocatalytic Ammonia Oxidation by a Low-Coordinate Copper Complex. J Am Chem Soc 2022; 144:21136-21145. [DOI: 10.1021/jacs.2c07977] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Md Estak Ahmed
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Chemistry, Georgetown University, Box 51277-1227, Washington, D.C. 20057, United States
| | - Mahdi Raghibi Boroujeni
- Department of Chemistry, Georgetown University, Box 51277-1227, Washington, D.C. 20057, United States
| | - Pokhraj Ghosh
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Chemistry, Georgetown University, Box 51277-1227, Washington, D.C. 20057, United States
| | - Christine Greene
- Department of Chemistry, Georgetown University, Box 51277-1227, Washington, D.C. 20057, United States
| | - Subrata Kundu
- Department of Chemistry, Georgetown University, Box 51277-1227, Washington, D.C. 20057, United States
- School of Chemistry, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala 695551, India
| | - Jeffery A. Bertke
- Department of Chemistry, Georgetown University, Box 51277-1227, Washington, D.C. 20057, United States
| | - Timothy H. Warren
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Chemistry, Georgetown University, Box 51277-1227, Washington, D.C. 20057, United States
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12
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Dunn PL, Barona M, Johnson SI, Raugei S, Bullock RM. Hydrogen Atom Abstraction from an Os II(NH 3) 2 Complex Generates an Os IV(NH 2) 2 Complex: Experimental and Computational Analysis of the N-H Bond Dissociation Free Energies and Reactivity. Inorg Chem 2022; 61:15325-15334. [PMID: 36121917 DOI: 10.1021/acs.inorgchem.2c00708] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Double hydrogen atom abstraction from (TMP)OsII(NH3)2 (TMP = tetramesitylporphyrin) with phenoxyl or nitroxyl radicals leads to (TMP)OsIV(NH2)2. This unusual bis(amide) complex is diamagnetic and displays an N-H resonance at 12.0 ppm in its 1H NMR spectrum. 1H-15N correlation experiments identified a 15N NMR spectroscopic resonance signal at -267 ppm. Experimental reactivity studies and density functional theory calculations support relatively weak N-H bonds of 73.3 kcal/mol for (TMP)OsII(NH3)2 and 74.2 kcal/mol for (TMP)OsIII(NH3)(NH2). Cyclic voltammetry experiments provide an estimate of the pKa of [(TMP)OsIII(NH3)2]+. In the presence of Barton's base, a current enhancement is observed at the Os(III/II) couple, consistent with an ECE event. Spectroscopic experiments confirmed (TMP)OsIV(NH2)2 as the product of bulk electrolysis. Double hydrogen atom abstraction is influenced by π donation from the amides of (TMP)OsIV(NH2)2 into the d orbitals of the Os center, favoring the formation of (TMP)OsIV(NH2)2 over N-N coupling. This π donation leads to a Jahn-Teller distortion that splits the energy levels of the dxz and dyz orbitals of Os, results in a low-spin electron configuration, and leads to minimal aminyl character on the N atoms, rendering (TMP)OsIV(NH2)2 unreactive toward amide-amide coupling.
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Affiliation(s)
- Peter L Dunn
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Melissa Barona
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Samantha I Johnson
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Simone Raugei
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - R Morris Bullock
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
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13
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Almquist CC, Removski N, Rajeshkumar T, Gelfand BS, Maron L, Piers WE. Spontaneous Ammonia Activation Through Coordination-Induced Bond Weakening in Molybdenum Complexes of a Dianionic Pentadentate Ligand Platform. Angew Chem Int Ed Engl 2022; 61:e202203576. [PMID: 35748415 DOI: 10.1002/anie.202203576] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Indexed: 11/10/2022]
Abstract
Ammonia oxidation catalyzed by molecular compounds is of current interest as a carbon-free source of dihydrogen. Activation of N-H bonds through coordination to transition metal centers is a key reaction in this process. We report the substantial activation of ammonia via reaction with low-valent molybdenum complexes of a diborate pentadentate ligand system. Spontaneous loss of dihydrogen from (B2 Pz4 Py)MoII -NH3 at room temperature to produce the dinuclear μ-nitrido compound (B2 Pz4 Py)Mo-N-Mo(B2 Pz4 Py) is observed due to substantial N-H bond weakening upon coordination to Mo. Mechanistic details are supported through the experimental observation/characterization of terminal amido, imido and nitrido complexes and density functional theory computations. The generally under-appreciated role of bridging nitrido intermediates is revealed and discussed, providing guidance for further catalyst development for this process.
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Affiliation(s)
- C Christopher Almquist
- Department of Chemistry, University of Calgary, 2500 University Dr. NW, T2N 1N4, AB, Calgary, Canada
| | - Nicole Removski
- Department of Chemistry, University of Calgary, 2500 University Dr. NW, T2N 1N4, AB, Calgary, Canada
| | - Thayalan Rajeshkumar
- LPCNO, INSA, UPS, Université de Toulouse, 135 avenue de Rangueil, 31077, Toulouse, France
| | - Benjamin S Gelfand
- Department of Chemistry, University of Calgary, 2500 University Dr. NW, T2N 1N4, AB, Calgary, Canada
| | - Laurent Maron
- LPCNO, INSA, UPS, Université de Toulouse, 135 avenue de Rangueil, 31077, Toulouse, France
| | - Warren E Piers
- Department of Chemistry, University of Calgary, 2500 University Dr. NW, T2N 1N4, AB, Calgary, Canada
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14
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Cook BJ, Barona M, Johnson SI, Raugei S, Bullock RM. Weakening the N-H Bonds of NH 3 Ligands: Triple Hydrogen-Atom Abstraction to Form a Chromium(V) Nitride. Inorg Chem 2022; 61:11165-11172. [PMID: 35829761 DOI: 10.1021/acs.inorgchem.2c01115] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Weakening and cleaving N-H bonds is crucial for improving molecular ammonia (NH3) oxidation catalysts. We report the synthesis and H-atom-abstraction reaction of bis(ammonia)chromium porphyrin complexes Cr(TPP)(NH3)2 and Cr(TMP)(NH3)2 (TPP = 5,10,15,20-tetraphenyl-meso-porphyrin and TMP = 5,10,15,20-tetramesityl-meso-porphyrin) using bulky aryloxyl radicals. The triple H-atom-abstraction reaction results in the formation of CrV(por)(≡N), with the nitride derived from NH3, as indicated by UV-vis and IR and single-crystal structural determination of Cr(TPP)(≡N). Subsequent oxidation of this chromium(V) nitrido complex results in the formation of CrIII(por), with scission of the Cr≡N bond. Computational analysis illustrates the progression from CrII to CrV and evaluates the energetics of abstracting H atoms from CrII-NH3 to generate CrV≡N. The formation and isolation of CrV(por)(≡N) illustrates the stability of these species and the need to chemically activate the nitride ligand for atom transfer or N-N coupling reactivity.
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Affiliation(s)
- Brian J Cook
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Melissa Barona
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Samantha I Johnson
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Simone Raugei
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - R Morris Bullock
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
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15
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Almquist CC, Removski N, Rajeshkumar T, Gelfand B, Piers W, Maron L. Spontaneous Ammonia Activation Through Coordination Induced Bond Weakening in Molybdenum Complexes of a Dianionic Pentadentate Ligand Platform. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202203576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
| | | | | | | | - Warren Piers
- University of Calgary Department of Chemistry 2500 University Dr. NW T2N 1N4 Calgary CANADA
| | - Laurent Maron
- University of Toulouse 3: Universite Toulouse III Paul Sabatier LPCNO FRANCE
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16
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Wei X, Wen X, Liu Y, Chen C, Xie C, Wang D, Qiu M, He N, Zhou P, Chen W, Cheng J, Lin H, Jia J, Fu XZ, Wang S. Oxygen Vacancy-Mediated Selective C-N Coupling toward Electrocatalytic Urea Synthesis. J Am Chem Soc 2022; 144:11530-11535. [PMID: 35748598 DOI: 10.1021/jacs.2c03452] [Citation(s) in RCA: 59] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The electrocatalytic C-N coupling for one-step urea synthesis under ambient conditions serves as the promising alternative to the traditional urea synthetic protocol. However, the hydrogenation of intermediate species hinders the efficient urea synthesis. Herein, the oxygen vacancy-enriched CeO2 was demonstrated as the efficient electrocatalyst with the stabilization of the crucial intermediate of *NO via inserting into vacant sites, which is conducive to the subsequent C-N coupling process rather than protonation, whereas the poor selectivity of C-N coupling with protonation was observed on the vacancy-deficient catalyst. The oxygen vacancy-mediated selective C-N coupling was distinguished and validated by the in situ sum frequency generation spectroscopy. The introduction of oxygen vacancies tailors the common catalyst carrier into an efficient electrocatalyst with a high urea yield rate of 943.6 mg h-1 g-1, superior than that of partial noble-metal-based electrocatalysts. This work provides novel insights into the catalyst design and developments of coupling systems.
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Affiliation(s)
- Xiaoxiao Wei
- State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University, Changsha, Hunan 410082, P. R. China.,College of Materials Science and Engineering, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong 518000, P. R. China
| | - Xiaojian Wen
- College of Materials Science and Engineering, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong 518000, P. R. China
| | - Yingying Liu
- State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University, Changsha, Hunan 410082, P. R. China
| | - Chen Chen
- State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University, Changsha, Hunan 410082, P. R. China
| | - Chao Xie
- State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University, Changsha, Hunan 410082, P. R. China
| | - Dongdong Wang
- State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University, Changsha, Hunan 410082, P. R. China
| | - Mengyi Qiu
- State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University, Changsha, Hunan 410082, P. R. China
| | - Nihan He
- State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University, Changsha, Hunan 410082, P. R. China
| | - Peng Zhou
- State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University, Changsha, Hunan 410082, P. R. China.,College of Materials Science and Engineering, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong 518000, P. R. China
| | - Wei Chen
- State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University, Changsha, Hunan 410082, P. R. China
| | - Jun Cheng
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361000, P. R. China
| | - Hongzhen Lin
- i-LAB, Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou, Jiangsu 215000, P. R. China
| | - Jianfeng Jia
- Key Laboratory of Magnetic Molecules and Magnetic Information Materials (Ministry of Education), School of Chemistry and Material Science, Shanxi Normal University, Taiyuan, Shanxi 030031, P. R. China
| | - Xian-Zhu Fu
- College of Materials Science and Engineering, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong 518000, P. R. China
| | - Shuangyin Wang
- State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University, Changsha, Hunan 410082, P. R. China
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17
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Connor GP, Delony D, Weber JE, Mercado BQ, Curley JB, Schneider S, Mayer JM, Holland PL. Facile conversion of ammonia to a nitride in a rhenium system that cleaves dinitrogen. Chem Sci 2022; 13:4010-4018. [PMID: 35440977 PMCID: PMC8985503 DOI: 10.1039/d1sc04503b] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Accepted: 02/22/2022] [Indexed: 11/21/2022] Open
Abstract
Rhenium complexes with aliphatic PNP pincer ligands have been shown to be capable of reductive N2 splitting to nitride complexes. However, the conversion of the resulting nitride to ammonia has not been observed. Here, the thermodynamics and mechanism of the hypothetical N–H bond forming steps are evaluated through the reverse reaction, conversion of ammonia to the nitride complex. Depending on the conditions, treatment of a rhenium(iii) precursor with ammonia gives either a bis(amine) complex [(PNP)Re(NH2)2Cl]+, or results in dehydrohalogenation to the rhenium(iii) amido complex, (PNP)Re(NH2)Cl. The N–H hydrogen atoms in this amido complex can be abstracted by PCET reagents which implies that they are quite weak. Calorimetric measurements show that the average bond dissociation enthalpy of the two amido N–H bonds is 57 kcal mol−1, while DFT computations indicate a substantially weaker N–H bond of the putative rhenium(iv)-imide intermediate (BDE = 38 kcal mol−1). Our analysis demonstrates that addition of the first H atom to the nitride complex is a thermochemical bottleneck for NH3 generation. Rhenium–PNP complexes split N2 to nitrides, but the nitrides do not give ammonia. Here, the thermodynamics of the hypothetical N–H bond forming steps are evaluated through the reverse reaction, showing that the first H addition is the bottleneck.![]()
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Affiliation(s)
- Gannon P Connor
- Department of Chemistry, Yale University New Haven Connecticut USA
| | - Daniel Delony
- Institute of Inorganic Chemistry, Georg-August-Universität Göttingen Göttingen Germany
| | - Jeremy E Weber
- Department of Chemistry, Yale University New Haven Connecticut USA
| | | | - Julia B Curley
- Department of Chemistry, Yale University New Haven Connecticut USA
| | - Sven Schneider
- Institute of Inorganic Chemistry, Georg-August-Universität Göttingen Göttingen Germany
| | - James M Mayer
- Department of Chemistry, Yale University New Haven Connecticut USA
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18
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Li Y, Chen JY, Miao Q, Yu X, Feng L, Liao RZ, Ye S, Tung CH, Wang W. A Parent Iron Amido Complex in Catalysis of Ammonia Oxidation. J Am Chem Soc 2022; 144:4365-4375. [PMID: 35234468 DOI: 10.1021/jacs.1c08609] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Parent amido complexes are crucial intermediates in ammonia-based transformations. We report a well-defined ferric ammine system [Cp*Fe(1,2-Ph2PC6H4NH)(NH3)]+ ([1-NH3]+), which processes electrocatalytic ammonia oxidation to N2 and H2 at a mild potential. Through establishing elementary e-/H+ conversions with the ferric ammine, a formal Fe(IV)-amido species, [1-NH2]+, together with its conjugated Lewis acid, [1-NH3]2+, was isolated and structurally characterized for the first time. Mechanism studies indicated that further oxidation of [1-NH2]+ induces the reaction of the parent amido unit with NH3. The formation of hydrazine is realized by the non-innocent nature of the phenylamido ligand that facilitates the concerted transfer of one proton and two electrons.
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Affiliation(s)
- Yongxian Li
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Jia-Yi Chen
- School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Qiyi Miao
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xin Yu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Lei Feng
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Rong-Zhen Liao
- School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Shengfa Ye
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.,Max-Planck-Institut für Kohlenforschung, D-45470 Mülheim an der Ruhr, Germany
| | - Chen-Ho Tung
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Wenguang Wang
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China.,College of Chemistry, Beijing Normal University, Beijing 100875, China
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19
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Barona M, Johnson SI, Mbea M, Bullock RM, Raugei S. Computational Investigations of the Reactivity of Metalloporphyrins for Ammonia Oxidation. Top Catal 2022. [DOI: 10.1007/s11244-021-01511-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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20
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Trenerry MJ, Wallen CM, Brown TR, Park SV, Berry JF. Spontaneous N 2 formation by a diruthenium complex enables electrocatalytic and aerobic oxidation of ammonia. Nat Chem 2021; 13:1221-1227. [PMID: 34750501 DOI: 10.1038/s41557-021-00797-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 08/24/2021] [Indexed: 11/09/2022]
Abstract
The electrochemical conversion of ammonia to dinitrogen in a direct ammonia fuel cell (DAFC) is a necessary technology for the realization of a nitrogen economy. Previous efforts to catalyse this reaction with molecular complexes required the addition of exogenous oxidizing reagents or application of potentials greater than the thermodynamic potential for the oxygen reduction reaction-the cathodic process of a DAFC. We report a stable metal-metal bonded diruthenium complex that spontaneously produces dinitrogen from ammonia under ambient conditions. The resulting reduced diruthenium material can be reoxidized with oxygen for subsequent reactions with ammonia, demonstrating its ability to spontaneously promote both half-reactions necessary for a DAFC. The diruthenium complex also acts as a redox mediator for the electrocatalytic oxidation of ammonia to dinitrogen at potentials as low as -255 mV versus Fc0/+ and operates below the oxygen reduction reaction potential in alkaline conditions, thus achieving a thermodynamic viability relevant for the future development of DAFCs.
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Affiliation(s)
- Michael J Trenerry
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Christian M Wallen
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Tristan R Brown
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Sungho V Park
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - John F Berry
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA.
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21
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Holub J, Vereshchuk N, Sánchez-Baygual FJ, Gil-Sepulcre M, Benet-Buchholz J, Llobet A. Synthesis, Structure, and Ammonia Oxidation Catalytic Activity of Ru-NH 3 Complexes Containing Multidentate Polypyridyl Ligands. Inorg Chem 2021; 60:13929-13940. [PMID: 34491057 DOI: 10.1021/acs.inorgchem.1c01528] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ammonia (electro)oxidation with molecular catalysts is a rapidly developing topic with wide practical applications ahead. We report here the catalytic ammonia oxidation reaction (AOR) activity using [Ru(tda-κ-N3O)(py)2], 2, (tda2- is 2,2':6',2''-terpyridine-6,6''-dicarboxylate; py is pyridine) as a catalyst precursor. Furthermore, we also describe the rich chemistry associated with the reaction of Ru-tda and Ru-tPa (tPa-4 is 2,2':6',2''-terpyridine-6,6''-diphosphonate) complexes with NH3 and N2H4 using [RuII(tda-κ-N3O)(dmso)Cl] (dmso is dimethyl sulfoxide) and [RuII(tPa-κ-N3O)(py)2], 8, as synthetic intermediates, respectively. All the new complexes obtained here were characterized spectroscopically by means of UV-vis and NMR. In addition, a crystal X-ray diffraction analysis was performed for complexes trans-[RuII(tda-κ-N3)(py)2(NH3)], 4, trans-[RuII(tda-κ-N3)(N-NH2)(py)2], 5, cis-[RuII(tda-κ-N3)(py)(NH3)2], 6 (30%), and cis-[RuII(tda-k-N3)(dmso)(NH3)2], 7 (70%). The AOR activity associated with 2 and 8 as catalyst precursors was studied in organic and aqueous media. For 2, turnover numbers of 7.5 were achieved under bulk electrolysis conditions at an Eapp = 1.4 V versus normal hydrogen electrode in acetonitrile. A catalytic cycle is proposed based on electrochemical and kinetic evidence.
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Affiliation(s)
- Jan Holub
- Institute of Chemical Research of Catalonia, Barcelona Institute of Science and Technology, Avda. Països Catalans 16, 43007 Tarragona, Spain
| | - Nataliia Vereshchuk
- Institute of Chemical Research of Catalonia, Barcelona Institute of Science and Technology, Avda. Països Catalans 16, 43007 Tarragona, Spain.,Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Marcel·lí Domingo s/n, 43007 Tarragona, Spain
| | - Francisco-Javier Sánchez-Baygual
- Institute of Chemical Research of Catalonia, Barcelona Institute of Science and Technology, Avda. Països Catalans 16, 43007 Tarragona, Spain
| | - Marcos Gil-Sepulcre
- Institute of Chemical Research of Catalonia, Barcelona Institute of Science and Technology, Avda. Països Catalans 16, 43007 Tarragona, Spain
| | - Jordi Benet-Buchholz
- Institute of Chemical Research of Catalonia, Barcelona Institute of Science and Technology, Avda. Països Catalans 16, 43007 Tarragona, Spain
| | - Antoni Llobet
- Institute of Chemical Research of Catalonia, Barcelona Institute of Science and Technology, Avda. Països Catalans 16, 43007 Tarragona, Spain.,Departament de Química, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193 Barcelona, Spain
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22
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Toda H, Kuroki K, Kanega R, Kuriyama S, Nakajima K, Himeda Y, Sakata K, Nishibayashi Y. Manganese-Catalyzed Ammonia Oxidation into Dinitrogen under Chemical or Electrochemical Conditions*. Chempluschem 2021; 86:1511-1516. [PMID: 34519172 DOI: 10.1002/cplu.202100349] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/11/2021] [Indexed: 11/06/2022]
Abstract
Earth-abundant metal-catalyzed oxidative conversion of ammonia into dinitrogen is a promising process to utilize ammonia as a transportation fuel. Herein, we report the manganese-catalyzed ammonia oxidation under chemical or electrochemical conditions using a manganese complex bearing (1S,2S)-N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediamine. Under chemical conditions using oxidant, up to 17.1 equivalents of N2 per catalyst are generated. Also, mechanistic studies by stoichiometric reactions reveal that a nucleophilic attack of ammonia on manganese nitrogenous species occurs to form a nitrogen-nitrogen bond leading to dinitrogen. Moreover, we conduct density functional theory (DFT) calculations to confirm the plausible reaction mechanism. In addition, this reaction system is applicable under electrochemical conditions. The catalytic reaction proceeds with 96 % faradaic efficiency (FE) in bulk electrolysis to give up to 6.56 equivalents of N2 per catalyst.
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Affiliation(s)
- Hiroki Toda
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, 113-8656, Bunkyo-ku, Tokyo, Japan
| | - Kaito Kuroki
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, 113-8656, Bunkyo-ku, Tokyo, Japan
| | - Ryoichi Kanega
- Department of Energy and Environment, National Institute of Advanced Industrial Science and Technology, 305-8565, Tsukuba, Ibaraki, Japan
| | - Shogo Kuriyama
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, 113-8656, Bunkyo-ku, Tokyo, Japan
| | - Kazunari Nakajima
- Frontier Research Center for Energy and Resources, School of Engineering, The University of Tokyo, Hongo, 113-8656, Bunkyo-ku, Tokyo, Japan
| | - Yuichiro Himeda
- Department of Energy and Environment, National Institute of Advanced Industrial Science and Technology, 305-8565, Tsukuba, Ibaraki, Japan
| | - Ken Sakata
- Faculty of Pharmaceutical Sciences, Toho University Miyama, 274-8510, Funabashi, Chiba, Japan
| | - Yoshiaki Nishibayashi
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, 113-8656, Bunkyo-ku, Tokyo, Japan
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23
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Wong A, Chakraborty A, Bawari D, Wu G, Dobrovetsky R, Ménard G. Facile proton-coupled electron transfer enabled by coordination-induced E-H bond weakening to boron. Chem Commun (Camb) 2021; 57:6903-6906. [PMID: 34151918 DOI: 10.1039/d1cc02832d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report the facile activation of aryl E-H (ArEH; E = N, O, S; Ar = Ph or C6F5) or ammonia N-H bonds via coordination-induced bond weakening to a redox-active boron center in the complex, (1-). Substantial decreases in E-H bond dissociation free energies (BDFEs) are observed upon substrate coordination, enabling subsequent facile proton-coupled electron transfer (PCET). A drop of >50 kcal mol-1 in H2N-H BDFE upon coordination was experimentally determined.
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Affiliation(s)
- Anthony Wong
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, USA.
| | - Arunavo Chakraborty
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, USA.
| | - Deependra Bawari
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, USA.
| | - Roman Dobrovetsky
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Gabriel Ménard
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, USA.
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24
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Immobilization of molecular catalysts on electrode surfaces using host-guest interactions. Nat Chem 2021; 13:523-529. [PMID: 33767362 DOI: 10.1038/s41557-021-00652-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 02/05/2021] [Indexed: 01/31/2023]
Abstract
Anchoring molecular catalysts on electrode surfaces combines the high selectivity and activity of molecular systems with the practicality of heterogeneous systems. Molecular catalysts, however, are far less stable than traditional heterogeneous electrocatalysts, and therefore a method to easily replace anchored molecular catalysts that have degraded could make such electrosynthetic systems more attractive. Here we applied a non-covalent 'click' chemistry approach to reversibly bind molecular electrocatalysts to electrode surfaces through host-guest complexation with surface-anchored cyclodextrins. The host-guest interaction is remarkably strong and enables the flow of electrons between the electrode and the guest catalyst. Electrosynthesis in both organic and aqueous media was demonstrated on metal oxide electrodes, with stability on the order of hours. The catalytic surfaces can be recycled by controlled release of the guest from the host cavities and the readsorption of fresh guest.
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25
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Wang Z, Johnson SI, Wu G, Ménard G. Multiple N-H and C-H Hydrogen Atom Abstractions Through Coordination-Induced Bond Weakening at Fe-Amine Complexes. Inorg Chem 2021; 60:8242-8251. [PMID: 34011142 DOI: 10.1021/acs.inorgchem.1c00923] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the use of the reported Fe-phthalocyanine complex, PcFe (1; Pc = 1,4,8,11,15,18,22,25-octaethoxy-phthalocyanine), to generate PcFe-amine complexes 1-(NH3)2, 1-(MeNH2)2, and 1-(Me2NH)2. Treatment of 1 or 1-(NH3)2 to an excess of the stable aryloxide radical, 2,4,6-tritert-butylphenoxyl radical (tBuArO•), under NH3 resulted in catalytic H atom abstraction (HAA) and C-N coupling to generate the product 4-amino-2,4,6-tritert-butylcyclohexa-2,5-dien-1-one (2) and tBuArOH. Exposing 1-(NH3)2 to an excess of the trityl (CPh3) variant, 2,6-di-tert-butyl-4-tritylphenoxyl radical (TrArO•), under NH3 did not lead to catalytic ammonia oxidation as previously reported in a related Ru-porphyrin complex. However, pronounced coordination-induced bond weakening of both α N-H and β C-H in the alkylamine congeners, 1-(MeNH2)2 and 1-(Me2NH)2, led to multiple HAA events yielding the unsaturated cyanide complex, 1-(MeNH2)(CN), and imine complex, 1-(MeN═CH2)2, respectively. Subsequent C-N bond formation was also observed in the latter upon addition of a coordinating ligand. Detailed computational studies support an alternating mechanism involving sequential N-H and C-H HAA to generate these unsaturated products.
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Affiliation(s)
- Zongheng Wang
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Samantha I Johnson
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Guang Wu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Gabriel Ménard
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
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26
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Zott MD, Peters JC. Enhanced Ammonia Oxidation Catalysis by a Low-Spin Iron Complex Featuring Cis Coordination Sites. J Am Chem Soc 2021; 143:7612-7616. [PMID: 33998805 DOI: 10.1021/jacs.1c02232] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The goal of using ammonia as a solar fuel motivates the development of selective ammonia oxidation (AO) catalysts for fuel cell applications. Herein, we describe Fe-mediated AO electrocatalysis with [(bpyPy2Me)Fe(MeCN)2]2+, exhibiting the highest turnover number (TON) reported to date for a molecular system. To improve on our recent report of a related iron AO electrocatalyst, [(TPA)Fe(MeCN)2]2+ (TON of 16), the present [(bpyPy2Me)Fe(MeCN)2]2+ system (TON of 149) features a stronger-field, more rigid auxiliary ligand that maintains cis-labile sites and a dominant low-spin population at the Fe(II) state. The latter is posited to mitigate demetalation and hence catalyst degradation by the presence of a large excess of ammonia under the catalytic conditions. Additionally, the [(bpyPy2Me)Fe(MeCN)2]2+ system exhibits a substantially faster AO rate (ca. 50×) at significantly lower (∼250 mV) applied bias compared to [(TPA)Fe(MeCN)2]2+. Electrochemical data are consistent with an initial E1 net H-atom abstraction step that furnishes the cis amide/ammine complex [(bpyPy2Me)Fe(NH2)(NH3)]2+, followed by the onset of catalysis at E2. Theoretical calculations suggest the possibility of N-N bond formation via multiple thermodynamically plausible pathways, including both reductive elimination and ammonia nucleophilic attack. In sum, this study underscores that Fe, an earth-abundant metal, is a promising metal for further development in metal-mediated AO catalysis by molecular systems.
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Affiliation(s)
- Michael D Zott
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Jonas C Peters
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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Tanabe Y, Nishibayashi Y. Comprehensive insights into synthetic nitrogen fixation assisted by molecular catalysts under ambient or mild conditions. Chem Soc Rev 2021; 50:5201-5242. [PMID: 33651046 DOI: 10.1039/d0cs01341b] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
N2 is fixed as NH3 industrially by the Haber-Bosch process under harsh conditions, whereas biological nitrogen fixation is achieved under ambient conditions, which has prompted development of alternative methods to fix N2 catalyzed by transition metal molecular complexes. Since the early 21st century, catalytic conversion of N2 into NH3 under ambient conditions has been achieved by using molecular catalysts, and now H2O has been utilized as a proton source with turnover frequencies reaching the values found for biological nitrogen fixation. In this review, recent advances in the development of molecular catalysts for synthetic N2 fixation under ambient or mild conditions are summarized, and potential directions for future research are also discussed.
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Affiliation(s)
- Yoshiaki Tanabe
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
| | - Yoshiaki Nishibayashi
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
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28
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Gu NX, Oyala PH, Peters JC. Hydrazine Formation via Coupling of a Nickel(III)-NH 2 Radical. Angew Chem Int Ed Engl 2021; 60:4009-4013. [PMID: 33152166 PMCID: PMC7902478 DOI: 10.1002/anie.202013119] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Indexed: 12/12/2022]
Abstract
M(NHx ) intermediates involved in N-N bond formation are central to ammonia oxidation (AO) catalysis, an enabling technology to ultimately exploit ammonia (NH3 ) as an alternative fuel source. While homocoupling of a terminal amide species (M-NH2 ) to form hydrazine (N2 H4 ) has been proposed, well-defined examples are without precedent. Herein, we discuss the generation and electronic structure of a NiIII -NH2 species that undergoes bimolecular coupling to generate a NiII 2 (N2 H4 ) complex. This hydrazine adduct can be further oxidized to a structurally unusual Ni2 (N2 H2 ) species; this releases N2 in the presence of NH3 , thus establishing a synthetic cycle for Ni-mediated AO. Distribution of the redox load for H2 N-NH2 formation via NH2 coupling between two metal centers presents an attractive strategy for AO catalysis using Earth-abundant, late first-row metals.
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Affiliation(s)
- Nina X Gu
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Paul H Oyala
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Jonas C Peters
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
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29
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Peng HL, Li Y, Chen XY, Li LP, Ke Z, Ye BH. Visible-Light-Induced Amination of Quinoline at the C8 Position via a Postcoordinated Interligand-Coupling Strategy under Mild Conditions. Inorg Chem 2021; 60:908-918. [PMID: 33393292 DOI: 10.1021/acs.inorgchem.0c03026] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The postcoordinated interligand-coupling strategy provides a useful and complementary protocol for synthesizing polydentate ligands. Herein, diastereoselective photoreactions of Λ-[Ir(pq)2(d-AA)] (Λ-d) and Λ-[Ir(pq)2(l-AA)] (Λ-l, where pq is 2-phenylquinoline and AA is an amino acid) are reported in the presence of O2 under mild conditions. Diastereomer Λ-d is dehydrogenatively oxidized into an imino acid complex, while diastereomer Λ-l mainly occurs via interligand C-N cross-dehydrogenative coupling between quinoline at the C8 position and AA ligands at room temperature, affording Λ-[Ir(pq)(l-pq-AA)]. Furthermore, the photoreaction of diastereomer Λ-l is temperature-dependent. Mechanistic experiments reveal the ligand-radical intermediates may be involved in the reaction. Density functional theory calculations were used to eluciate the origin of diastereoselectivity and temperature dependence. This will provide a new protocol for the amination of quinoline at the C8 position via the postcoordinated interligand C-N cross-coupling strategy under mild conditions.
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Affiliation(s)
- He-Long Peng
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, Guangdong, China
| | - Yinwu Li
- School of Materials Science & Engineering, Sun Yat-sen University, Guangzhou 510275, Guangdong, China
| | - Xing-Yang Chen
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, Guangdong, China
| | - Li-Ping Li
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, Guangdong, China
| | - Zhuofeng Ke
- School of Materials Science & Engineering, Sun Yat-sen University, Guangzhou 510275, Guangdong, China
| | - Bao-Hui Ye
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, Guangdong, China
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30
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Gu NX, Oyala PH, Peters JC. Hydrazine Formation via Coupling of a Nickel(III)–NH
2
Radical. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202013119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Nina X. Gu
- Division of Chemistry and Chemical Engineering California Institute of Technology Pasadena CA 91125 USA
| | - Paul H. Oyala
- Division of Chemistry and Chemical Engineering California Institute of Technology Pasadena CA 91125 USA
| | - Jonas C. Peters
- Division of Chemistry and Chemical Engineering California Institute of Technology Pasadena CA 91125 USA
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31
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Nurdin L, Yang Y, Neate PGN, Piers WE, Maron L, Neidig ML, Lin JB, Gelfand BS. Activation of ammonia and hydrazine by electron rich Fe(ii) complexes supported by a dianionic pentadentate ligand platform through a common terminal Fe(iii) amido intermediate. Chem Sci 2020; 12:2231-2241. [PMID: 34163989 PMCID: PMC8179247 DOI: 10.1039/d0sc06466a] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
We report the use of electron rich iron complexes supported by a dianionic diborate pentadentate ligand system, B2Pz4Py, for the coordination and activation of ammonia (NH3) and hydrazine (NH2NH2). For ammonia, coordination to neutral (B2Pz4Py)Fe(ii) or cationic [(B2Pz4Py)Fe(iii)]+ platforms leads to well characterized ammine complexes from which hydrogen atoms or protons can be removed to generate, fleetingly, a proposed (B2Pz4Py)Fe(iii)–NH2 complex (3Ar-NH2). DFT computations suggest a high degree of spin density on the amido ligand, giving it significant aminyl radical character. It rapidly traps the H atom abstracting agent 2,4,6-tri-tert-butylphenoxy radical (ArO˙) to form a C–N bond in a fully characterized product (2Ar), or scavenges hydrogen atoms to return to the ammonia complex (B2Pz4Py)Fe(ii)–NH3 (1Ar-NH3). Interestingly, when (B2Pz4Py)Fe(ii) is reacted with NH2NH2, a hydrazine bridged dimer, (B2Pz4Py)Fe(ii)–NH2NH2–Fe(ii)(B2Pz4Py) ((1Ar)2-NH2NH2), is observed at −78 °C and converts to a fully characterized bridging diazene complex, 4Ar, along with ammonia adduct 1Ar-NH3 as it is allowed to warm to room temperature. Experimental and computational evidence is presented to suggest that (B2Pz4Py)Fe(ii) induces reductive cleavage of the N–N bond in hydrazine to produce the Fe(iii)–NH2 complex 3Ar-NH2, which abstracts H˙ atoms from (1Ar)2-NH2NH2 to generate the observed products. All of these transformations are relevant to proposed steps in the ammonia oxidation reaction, an important process for the use of nitrogen-based fuels enabled by abundant first row transition metals. Synopsis: a highly reactive Fe(iii)–NH2 complex is generated via activation of ammonia or hydrazine in reactions of relevance to fundamental steps in ammonia oxidation processes mediated by an abundant, first row transition metal.![]()
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Affiliation(s)
- Lucie Nurdin
- Department of Chemistry, University of Calgary 2500 University Drive NW Calgary Alberta T2N 1N4 Canada
| | - Yan Yang
- LPCNO, Université de Toulouse, INSA, UPS Toulouse France
| | - Peter G N Neate
- Department of Chemistry, University of Rochester Rochester New York 14627 USA
| | - Warren E Piers
- Department of Chemistry, University of Calgary 2500 University Drive NW Calgary Alberta T2N 1N4 Canada
| | - Laurent Maron
- LPCNO, Université de Toulouse, INSA, UPS Toulouse France
| | - Michael L Neidig
- Department of Chemistry, University of Rochester Rochester New York 14627 USA
| | - Jian-Bin Lin
- Department of Chemistry, University of Calgary 2500 University Drive NW Calgary Alberta T2N 1N4 Canada
| | - Benjamin S Gelfand
- Department of Chemistry, University of Calgary 2500 University Drive NW Calgary Alberta T2N 1N4 Canada
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32
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Dunn PL, Cook BJ, Johnson SI, Appel AM, Bullock RM. Oxidation of Ammonia with Molecular Complexes. J Am Chem Soc 2020; 142:17845-17858. [PMID: 32977718 DOI: 10.1021/jacs.0c08269] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Oxidation of ammonia by molecular complexes is a burgeoning area of research, with critical scientific challenges that must be addressed. A fundamental understanding of individual reaction steps is needed, particularly for cleavage of N-H bonds and formation of N-N bonds. This Perspective evaluates the challenges of designing molecular catalysts for oxidation of ammonia and highlights recent key contributions to realizing the goals of viable energy storage and retrieval based on the N-H bonds of ammonia in a carbon-free energy cycle.
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Affiliation(s)
- Peter L Dunn
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Brian J Cook
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Samantha I Johnson
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Aaron M Appel
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - R Morris Bullock
- Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
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33
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Bezdek MJ, Pelczer I, Chirik PJ. Coordination-Induced N–H Bond Weakening in a Molybdenum Pyrrolidine Complex: Isotopic Labeling Provides Insight into the Pathway for H 2 Evolution. Organometallics 2020. [DOI: 10.1021/acs.organomet.0c00471] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Máté J. Bezdek
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - István Pelczer
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Paul J. Chirik
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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34
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Wang F, Gerken JB, Bates DM, Kim YJ, Stahl SS. Electrochemical Strategy for Hydrazine Synthesis: Development and Overpotential Analysis of Methods for Oxidative N-N Coupling of an Ammonia Surrogate. J Am Chem Soc 2020; 142:12349-12356. [PMID: 32520537 PMCID: PMC7373162 DOI: 10.1021/jacs.0c04626] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Hydrazine is an important industrial chemical and fuel that has attracted considerable attention for use in liquid fuel cells. Ideally, hydrazine could be prepared via direct oxidative coupling of ammonia, but thermodynamic and kinetic factors limit the viability of this approach. The present study evaluates three different electrochemical strategies for the oxidative homocoupling of benzophenone imine, a readily accessible ammonia surrogate. Hydrolysis of the resulting benzophenone azine affords hydrazine and benzophenone, with the latter amenable to recycling. The three different electrochemical N-N coupling methods are (1) a proton-coupled electron-transfer process promoted by a phosphate base, (2) an iodine-mediated reaction involving intermediate N-I bond formation, and (3) a copper-catalyzed N-N coupling process. Analysis of the thermodynamic efficiencies for these electrochemical imine-to-azine oxidation reactions reveals low overpotentials (η) for the copper- and iodine-mediated processes (390 and 470 mV, respectively), but a much higher value for the proton-coupled pathway (η ≈ 1.6 V). A similar approach is used to assess molecular electrocatalytic methods for electrochemical oxidation of ammonia to dinitrogen.
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Affiliation(s)
- Fei Wang
- Department of Chemistry, University of Wisconsin - Madison, 1101 University Ave, Madison, Wisconsin, 53706, United States
| | - James B. Gerken
- Department of Chemistry, University of Wisconsin - Madison, 1101 University Ave, Madison, Wisconsin, 53706, United States
| | - Desiree M. Bates
- Department of Chemistry, University of Wisconsin - Madison, 1101 University Ave, Madison, Wisconsin, 53706, United States
| | - Yeon Jung Kim
- Department of Chemistry, University of Wisconsin - Madison, 1101 University Ave, Madison, Wisconsin, 53706, United States
| | - Shannon S. Stahl
- Department of Chemistry, University of Wisconsin - Madison, 1101 University Ave, Madison, Wisconsin, 53706, United States
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35
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Amitina SA, Zaytseva EV, Dmitrieva NA, Lomanovich AV, Kandalintseva NV, Ten YA, Artamonov IA, Markov AF, Mazhukin DG. 5-Aryl-2-(3,5-dialkyl-4-hydroxyphenyl)-4,4-dimethyl-4 H-imidazole 3-Oxides and Their Redox Species: How Antioxidant Activity of 1-Hydroxy-2,5-dihydro-1 H-imidazoles Correlates with the Stability of Hybrid Phenoxyl-Nitroxides. Molecules 2020; 25:E3118. [PMID: 32650477 PMCID: PMC7396990 DOI: 10.3390/molecules25143118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 07/05/2020] [Accepted: 07/07/2020] [Indexed: 11/16/2022] Open
Abstract
Cyclic nitrones of the imidazole series, containing a sterically hindered phenol group, are promising objects for studying antioxidant activity; on the other hand, they can form persistent hybrid phenoxyl-nitroxyl radicals (HPNs) upon oxidation. Here, a series of 5-aryl-4,4-dimethyl-4H-imidazole 3-oxides was obtained by condensation of aromatic 2-hydroxylaminoketones with 4-formyl-2,6-dialkylphenols followed by oxidation of the initially formed N-hydroxy derivatives. It was shown that the antioxidant activity of both 1-hydroxy-2,5-dihydroimidazoles and 4H-imidazole 3-oxides increases with a decrease in steric volume of the alkyl substituent in the phenol group, while the stability of the corresponding HPNs generated from 4H-imidazole 3-oxides reveals the opposite tendency.
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Affiliation(s)
- Svetlana A. Amitina
- Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Academician Lavrentiev Ave. 9, 630090 Novosibirsk, Russia; (S.A.A.); (E.V.Z.); (A.V.L.); (Y.A.T.); (I.A.A.)
| | - Elena V. Zaytseva
- Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Academician Lavrentiev Ave. 9, 630090 Novosibirsk, Russia; (S.A.A.); (E.V.Z.); (A.V.L.); (Y.A.T.); (I.A.A.)
| | - Natalya A. Dmitrieva
- Department of Chemistry, Institute of Chemistry of Antioxidants, Novosibirsk State Pedagogical University, Vilyuyskaya Str. 28, 6301026 Novosibirsk, Russia; (N.A.D.); (N.V.K.); (A.F.M.)
| | - Alyona V. Lomanovich
- Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Academician Lavrentiev Ave. 9, 630090 Novosibirsk, Russia; (S.A.A.); (E.V.Z.); (A.V.L.); (Y.A.T.); (I.A.A.)
| | - Natalya V. Kandalintseva
- Department of Chemistry, Institute of Chemistry of Antioxidants, Novosibirsk State Pedagogical University, Vilyuyskaya Str. 28, 6301026 Novosibirsk, Russia; (N.A.D.); (N.V.K.); (A.F.M.)
| | - Yury A. Ten
- Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Academician Lavrentiev Ave. 9, 630090 Novosibirsk, Russia; (S.A.A.); (E.V.Z.); (A.V.L.); (Y.A.T.); (I.A.A.)
| | - Ilya A. Artamonov
- Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Academician Lavrentiev Ave. 9, 630090 Novosibirsk, Russia; (S.A.A.); (E.V.Z.); (A.V.L.); (Y.A.T.); (I.A.A.)
| | - Alexander F. Markov
- Department of Chemistry, Institute of Chemistry of Antioxidants, Novosibirsk State Pedagogical University, Vilyuyskaya Str. 28, 6301026 Novosibirsk, Russia; (N.A.D.); (N.V.K.); (A.F.M.)
| | - Dmitrii G. Mazhukin
- Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Sciences (SB RAS), Academician Lavrentiev Ave. 9, 630090 Novosibirsk, Russia; (S.A.A.); (E.V.Z.); (A.V.L.); (Y.A.T.); (I.A.A.)
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