1
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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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2
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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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3
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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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4
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He Y, Huang YY, Zhu XQ, Su SD, Xu QD, Fu JH, Song Y, Wu XT, Sheng TL. Electronic Transition and Magnetic Coupling Regulation in Trimetallic Complexes Featuring a New Bridging Ligand Obtained by Oxidative Addition. Inorg Chem 2023. [PMID: 37452753 DOI: 10.1021/acs.inorgchem.3c01339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2023]
Abstract
A series of trimetallic complexes [FeIII(μ-L)(py)]2MII(py)n (n = 2, MII = MnII, 1; FeII, 2; CoII, 3; ZnII, 4; n = 3, MII = CdII, 5) with a new bridging ligand L4- (deprotonated 1,2-N1,N2-bis(2-mercaptoanil) oxalimidic acid) were synthesized and fully characterized by elemental analysis, single-crystal X-ray crystallography, IR, and Mössbauer spectra. Interestingly, the bridging ligand was obtained by oxidative addition of the (gma•)3- ligand from the mononuclear precursor Fe(gma)py (gma = glyoxal-bis(2-mercaptoanil)). In the obtained complexes, the bridging ligand L4- coordinates to the terminal FeIII ions (intermediate-spin with SFe = 3/2) by the N, S atoms, and coordinate to the central metal MII ion by the four O atoms. The resonance structure of the bridging ligand can be described as the two 4π-electron delocalized systems connected by one single-bond (C1-C2), which is different from the electronic structure of the precursor Fe(gma)py. Remarkably, the magnetic coupling interaction can be regulated through the central metal. The ferromagnetic coupling constant J gradually decreases as MII changes from FeII to CoII and MnII, while the paramagnetic behaviors are presented when MII = ZnII and CdII, confirmed by the magnetic susceptibility measurements and further supported by using the PHI program. Furthermore, the bridging ligand to the terminal FeIII charge transfer (LMCT) transitions emerged in all complexes but the central FeII to terminal FeIII charge transfer (MMCT) only presented in complex 2, strongly supported by the UV/vis-NIR electronic spectra and TDDFT calculations.
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Affiliation(s)
- Yong He
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, P. R. China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Ying-Ying Huang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, P. R. China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Xiao-Quan Zhu
- Department of Criminal Investigation, Fujian Police College, Fuzhou 350007, P. R. China
| | - Shao-Dong Su
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, P. R. China
| | - Qing-Dou Xu
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, P. R. China
| | - Jin-Hui Fu
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, P. R. China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Ying Song
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, P. R. China
| | - Xin-Tao Wu
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, P. R. China
| | - Tian-Lu Sheng
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, P. R. China
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5
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Beh DW, Cuellar De Lucio AJ, del Rosal I, Maron L, Spasyuk D, Gelfand BS, Li JB, Piers WE. Organotitanium Complexes Supported by a Dianionic Pentadentate Ligand. Organometallics 2023. [DOI: 10.1021/acs.organomet.2c00609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2023]
Affiliation(s)
- Daniel W. Beh
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | | | - Iker del Rosal
- LPCNO, Université de Toulouse, INSA, UPS, LPCNO, 135 avenue de Rangueil, F-31077 Toulouse, France
- CNRS, LPCNO, F-31077 Toulouse, France
| | - Laurent Maron
- LPCNO, Université de Toulouse, INSA, UPS, LPCNO, 135 avenue de Rangueil, F-31077 Toulouse, France
- CNRS, LPCNO, F-31077 Toulouse, France
| | - Denis Spasyuk
- Canadian Light Source Inc., 44 Innovation Boulevard, Saskatoon, Saskatchewan S7N 2V3, Canada
| | - Benjamin S. Gelfand
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Jian-Bin Li
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Warren E. Piers
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
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6
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Auer M, Bolten J, Eichele K, Schubert H, Sindlinger CP, Wesemann L. Heavy metalla vinyl-cations show metal-Lewis acid cooperativity in reaction with small molecules (NH 3, N 2H 4, H 2O, H 2). Chem Sci 2023; 14:514-524. [PMID: 36741530 PMCID: PMC9847682 DOI: 10.1039/d2sc05620h] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 11/24/2022] [Indexed: 11/25/2022] Open
Abstract
Halide abstraction from tetrylidene complexes [TbbE(Br)IrH(PMe3)3] [E = Ge (1), Sn (2)] and [Ar*E(Cl)IrH(PMe3)3] gives the salts [TbbEIrH(PMe3)3][BArF 4] [E = Ge (3), Sn (4)] and [Ar*EIrH(PMe3)3][BArF 4] [E = Ge (3'), E = Sn (4')] (Tbb = 2,6-[CH(SiMe3)2]2-4-(t-Bu)C6H2, Ar* = 2,6-Trip2C6H3, Trip = 2,4,6-triisopropylphenyl). Bonding analysis suggests their most suitable description as metalla-tetrela vinyl cations with an Ir[double bond, length as m-dash]E double bond and a near linear coordination at the Ge/Sn atoms. Cationic complexes 3 and 4 oxidatively add NH3, N2H4, H2O, HCl, and H2 selectively to give: [TbbGe(NH2)IrH2(PMe3)3][BArF 4] (5), [TbbE(NHNH2)IrH2(PMe3)3][BArF 4] [E = Ge (7), Sn (8)], [TbbE(OH)IrH2(PMe3)3][BArF 4] [E = Ge (9), Sn (10)], [TbbE(Cl)IrH2(PMe3)3][BArF 4] [E = Ge (11a), Sn (12a)], [TbbGe(H)IrH2(PMe3)3][BArF 4] (13), [TbbSn(μ-H3)Ir(PMe3)3][BArF 4] (14), and [TbbSn(H)IrH2(PMe3)3][BArF 4] (15). 14 isomerizes to give 15via an 1,2-H shift reaction. Hydride addition to cation 3 gives a mixture of products [TbbGeHIrH(PMe3)3] (16) and [TbbGeIrH2(PMe3)3] (17) and a reversible 1,2-H shift between 16 and 17 was studied. In the tin case 4 the dihydride [TbbSnIrH2(PMe3)3] (18) was isolated exclusively. The PMe3 and PEt3 derivatives, 18 and [TbbSnIrH2(PEt3)3] (19), respectively, could also be synthesized in reaction of [TbbSnH2]- with the respective chloride [(R3P) n IrCl] (R = Me, n = 4; R = Et, n = 3). Reaction of complex 19 with CO gives the substitution product [TbbSnIrH2(CO)(PEt3)2] (20). Further reaction with CO results in hydrogen transfer from the iridium to the tin atom to give [TbbSnH2Ir(CO)2(PEt3)2] (21). The reversibility of this ligand induced reductive elimination transferring 20 to 21 is shown.
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Affiliation(s)
- Maximilian Auer
- Institut für Anorganische ChemieAuf der Morgenstelle 1872076 TübingenGermany
| | - Janina Bolten
- Institut für Anorganische ChemieAuf der Morgenstelle 1872076 TübingenGermany
| | - Klaus Eichele
- Institut für Anorganische ChemieAuf der Morgenstelle 1872076 TübingenGermany
| | - Hartmut Schubert
- Institut für Anorganische ChemieAuf der Morgenstelle 1872076 TübingenGermany
| | - Christian P. Sindlinger
- Institut für Anorganische Chemie, Universität StuttgartPfaffenwaldring 5570569 StuttgartGermany
| | - Lars Wesemann
- Institut für Anorganische ChemieAuf der Morgenstelle 1872076 TübingenGermany
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7
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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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8
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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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9
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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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10
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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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11
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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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12
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Abstract
This tutorial review showcases recent (2015-2021) work describing ligand construction as it relates to the design of secondary coordination spheres (SCSs). Metalloenzymes, for example, utilize SCSs to stabilize reactive substrates, shuttle small molecules, and alter redox properties, promoting functional activity. In the realm of biomimetic chemistry, specific incorporation of SCS residues (e.g., Brønsted or Lewis acid/bases, crown ethers, redox groups etc.) has been shown to be equally critical to function. This contribution illustrates how fundamental advances in organic and inorganic chemistry have been used for the construction of such SCSs. These imaginative contributions have driven exciting findings in many transformations relevant to clean fuel generation, including small molecule (e.g., H+, N2, CO2, NOx, O2) reduction. In most cases, these reactions occur cooperatively, where both metal and ligand are requisite for substrate activation.
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Affiliation(s)
- Marcus W Drover
- Department of Chemistry and Biochemistry, The University of Windsor, 401 Sunset Avenue, Windsor, ON, N9B 3P4, Canada.
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13
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Zurakowski JA, Austen BJ, Drover MW. Exterior decorating: Lewis acid secondary coordination spheres for cooperative reactivity. TRENDS IN CHEMISTRY 2022. [DOI: 10.1016/j.trechm.2022.01.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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14
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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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15
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Goura J, McQuade J, Shimoyama D, Lalancette RA, Sheridan JB, Jäkle F. Electrophilic and nucleophilic displacement reactions at the bridgehead borons of tris(pyridyl)borate scorpionate complexes. Chem Commun (Camb) 2022; 58:977-980. [PMID: 34979540 DOI: 10.1039/d1cc06181j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Although a wide variety of boron-based "scorpionate" ligands have been implemented, a modular route that offers facile access to different substitution patterns at boron has yet to be developed. Here, we demonstrate new reactivity patterns at the bridgehead positions of a ruthenium tris(pyrid-2-yl)borate complex that allow for facile tuning of steric and electronic properties.
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Affiliation(s)
- Joydeb Goura
- Department of Chemistry, Rutgers University-Newark, Newark, NJ 07102, USA.
| | - James McQuade
- Department of Chemistry, Rutgers University-Newark, Newark, NJ 07102, USA.
| | - Daisuke Shimoyama
- Department of Chemistry, Rutgers University-Newark, Newark, NJ 07102, USA.
| | - Roger A Lalancette
- Department of Chemistry, Rutgers University-Newark, Newark, NJ 07102, USA.
| | - John B Sheridan
- Department of Chemistry, Rutgers University-Newark, Newark, NJ 07102, USA.
| | - Frieder Jäkle
- Department of Chemistry, Rutgers University-Newark, Newark, NJ 07102, USA.
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16
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Li Y, Su L, Yang D, Di K, Wang B, Qu J. A thiolate-bridged ruthenium-molybdenum complex featuring terminal nitrido and bridging amido ligands derived from N−H and N−N bond cleavage of hydrazine. Dalton Trans 2022; 51:10866-10870. [DOI: 10.1039/d2dt01378a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Biomimetic di- or multimetallic complexes featuring NxHy species in a sulfur-rich coordination sphere have attracted considerable attention in modelling the possible scenarios of biological nitrogen fixation by nitrogenases. Although the...
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17
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Agarwal RG, Coste SC, Groff BD, Heuer AM, Noh H, Parada GA, Wise CF, Nichols EM, Warren JJ, Mayer JM. Free Energies of Proton-Coupled Electron Transfer Reagents and Their Applications. Chem Rev 2021; 122:1-49. [PMID: 34928136 DOI: 10.1021/acs.chemrev.1c00521] [Citation(s) in RCA: 103] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We present an update and revision to our 2010 review on the topic of proton-coupled electron transfer (PCET) reagent thermochemistry. Over the past decade, the data and thermochemical formalisms presented in that review have been of value to multiple fields. Concurrently, there have been advances in the thermochemical cycles and experimental methods used to measure these values. This Review (i) summarizes those advancements, (ii) corrects systematic errors in our prior review that shifted many of the absolute values in the tabulated data, (iii) provides updated tables of thermochemical values, and (iv) discusses new conclusions and opportunities from the assembled data and associated techniques. We advocate for updated thermochemical cycles that provide greater clarity and reduce experimental barriers to the calculation and measurement of Gibbs free energies for the conversion of X to XHn in PCET reactions. In particular, we demonstrate the utility and generality of reporting potentials of hydrogenation, E°(V vs H2), in almost any solvent and how these values are connected to more widely reported bond dissociation free energies (BDFEs). The tabulated data demonstrate that E°(V vs H2) and BDFEs are generally insensitive to the nature of the solvent and, in some cases, even to the phase (gas versus solution). This Review also presents introductions to several emerging fields in PCET thermochemistry to give readers windows into the diversity of research being performed. Some of the next frontiers in this rapidly growing field are coordination-induced bond weakening, PCET in novel solvent environments, and reactions at material interfaces.
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Affiliation(s)
- Rishi G Agarwal
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Scott C Coste
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Benjamin D Groff
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Abigail M Heuer
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Hyunho Noh
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Giovanny A Parada
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States.,Department of Chemistry, The College of New Jersey, Ewing, New Jersey 08628, United States
| | - Catherine F Wise
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Eva M Nichols
- Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Jeffrey J Warren
- Department of Chemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - James M Mayer
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
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18
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Keener M, Scopelliti R, Mazzanti M. Nitride protonation and NH 3 binding versus N-H bond cleavage in uranium nitrides. Chem Sci 2021; 12:12610-12618. [PMID: 34703546 PMCID: PMC8494049 DOI: 10.1039/d1sc03957a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 08/13/2021] [Indexed: 11/24/2022] Open
Abstract
The conversion of metal nitrides to NH3 is an essential step in dinitrogen fixation, but there is limited knowledge of the reactivity of nitrides with protons (H+). Herein, we report comparative studies for the reactions of H+ and NH3 with uranium nitrides, containing different types of ancillary ligands. We show that the differences in ancillary ligands, leads to dramatically different reactivity. The nitride group, in nitride-bridged cationic and anionic diuranium(iv) complexes supported by –N(SiMe3)2 ligands, is resistant toward protonation by weak acids, while stronger acids result in ligand loss by protonolysis. Moreover, the basic –N(SiMe3)2 ligands promote the N–H heterolytic bond cleavage of NH3, yielding a “naked” diuranium complex containing three bridging ligands, a nitride (N3−) and two NH2 ligands. Conversely, in the nitride-bridged diuranium(iv) complex supported by –OSi(OtBu)3 ligands, the nitride group is easily protonated to afford NH3, which binds the U(iv) ion strongly, resulting in a mononuclear U–NH3 complex, where NH3 can be displaced by addition of strong acids. Furthermore, the U–OSi(OtBu)3 bonds were found to be stable, even in the presence of stronger acids, such as NH4BPh4, therefore indicating that –OSi(OtBu)3 supporting ligands are well suited to be used when acidic conditions are required, such as in the H+/e− mediated catalytic conversion of N2 to NH3. Ancillary ligands alter the reactivity of U-nitrides with H+, relevant to N2 conversion to NH3. The amides lead to complete ligand loss and NH3 activation, while for siloxides, the nitride is protonated to NH3 leaving the ancillary ligands intact.![]()
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Affiliation(s)
- Megan Keener
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Rosario Scopelliti
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Marinella Mazzanti
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
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19
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Gardner EJ, Marguet SC, Cobb CR, Pham DM, Beringer JAM, Bertke JA, Shafaat HS, Warren TH. Uncovering Redox Non-innocent Hydrogen-Bonding in Cu(I)-Diazene Complexes. J Am Chem Soc 2021; 143:15960-15974. [PMID: 34546737 DOI: 10.1021/jacs.1c04108] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The life-sustaining reduction of N2 to NH3 is thermoneutral yet kinetically challenged by high-energy intermediates such as N2H2. Exploring intramolecular H-bonding as a potential strategy to stabilize diazene intermediates, we employ a series of [xHetTpCu]2(μ-N2H2) complexes that exhibit H-bonding between pendant aromatic N-heterocycles (xHet) such as pyridine and a bridging trans-N2H2 ligand at copper(I) centers. X-ray crystallography and IR spectroscopy clearly reveal H-bonding in [pyMeTpCu]2(μ-N2H2) while low-temperature 1H NMR studies coupled with DFT analysis reveals a dynamic equilibrium between two closely related, symmetric H-bonded structural motifs. Importantly, the xHet pendant negligibly influences the electronic structure of xHetTpCuI centers in xHetTpCu(CNAr2,6-Me2) complexes that lack H-bonding as judged by nearly indistinguishable ν(CN) frequencies (2113-2117 cm-1). Nonetheless, H-bonding in the corresponding [xHetTpCu]2(μ-N2H2) complexes results in marked changes in ν(NN) (1398-1419 cm-1) revealed through resonance Raman studies. Due to the closely matched N-H BDEs of N2H2 and the pyH0 cation radical, the aromatic N-heterocyclic pendants may encourage partial H-atom transfer (HAT) from N2H2 to xHet through redox-non-innocent H-bonding in [xHetTpCu]2(μ-N2H2). DFT studies reveal modest thermodynamic barriers for concerted transfer of both H-atoms of coordinated N2H2 to the xHet pendants to generate tautomeric [xHetHTpCu]2(μ-N2) complexes, identifying metal-assisted concerted dual HAT as a thermodynamically favorable pathway for N2/N2H2 interconversion.
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Affiliation(s)
- Evan J Gardner
- Department of Chemistry, Georgetown University, Box 51277-1227, Washington, D.C. 20057, United States
| | - Sean C Marguet
- The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Caitlyn R Cobb
- Department of Chemistry, Georgetown University, Box 51277-1227, Washington, D.C. 20057, United States
| | - Dominic M Pham
- Department of Chemistry, Georgetown University, Box 51277-1227, Washington, D.C. 20057, United States
| | - Josalyne A M Beringer
- Department of Chemistry, Georgetown University, Box 51277-1227, Washington, D.C. 20057, United States
| | - Jeffery A Bertke
- Department of Chemistry, Georgetown University, Box 51277-1227, Washington, D.C. 20057, United States
| | - Hannah S Shafaat
- The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Timothy H Warren
- Department of Chemistry, Georgetown University, Box 51277-1227, Washington, D.C. 20057, United States
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