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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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Keilwerth M, Mao W, Malischewski M, Jannuzzi SAV, Breitwieser K, Heinemann FW, Scheurer A, DeBeer S, Munz D, Bill E, Meyer K. The synthesis and characterization of an iron(VII) nitrido complex. Nat Chem 2024; 16:514-520. [PMID: 38291260 PMCID: PMC10997499 DOI: 10.1038/s41557-023-01418-4] [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: 08/18/2023] [Accepted: 12/08/2023] [Indexed: 02/01/2024]
Abstract
Complexes of iron in high oxidation states are captivating research subjects due to their pivotal role as active intermediates in numerous catalytic processes. Structural and spectroscopic studies of well-defined model complexes often provide evidence of these intermediates. In addition to the fundamental molecular and electronic structure insights gained by these complexes, their reactivity also affects our understanding of catalytic reaction mechanisms for small molecule and bond-activation chemistry. Here, we report the synthesis, structural and spectroscopic characterization of a stable, octahedral Fe(VI) nitrido complex and an authenticated, unique Fe(VII) species, prepared by one-electron oxidation. The super-oxidized Fe(VII) nitride rearranges to an Fe(V) imide through an intramolecular amination mechanism and ligand exchange, which is characterized spectroscopically and computationally. This enables combined reactivity and stability studies on a single molecular system of a rare high-valent complex redox pair. Quantum chemical calculations complement the spectroscopic parameters and provide evidence for a diamagnetic (S = 0) d 2 Fe(VI) and a genuine S = 1/2, d 1 Fe(VII) configuration of these super-oxidized nitrido complexes.
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Affiliation(s)
- Martin Keilwerth
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Department of Chemistry and Pharmacy, Inorganic Chemistry, Erlangen, Germany
| | - Weiqing Mao
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Department of Chemistry and Pharmacy, Inorganic Chemistry, Erlangen, Germany
| | - Moritz Malischewski
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Inorganic Chemistry, Berlin, Germany
| | - Sergio A V Jannuzzi
- Max Planck Institute for Chemical Energy Conversion, Mülheim an der Ruhr, Germany
| | - Kevin Breitwieser
- Saarland University, Inorganic Chemistry, Coordination Chemistry, Saarbrücken, Germany
| | - Frank W Heinemann
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Department of Chemistry and Pharmacy, Inorganic Chemistry, Erlangen, Germany
| | - Andreas Scheurer
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Department of Chemistry and Pharmacy, Inorganic Chemistry, Erlangen, Germany
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion, Mülheim an der Ruhr, Germany.
| | - Dominik Munz
- Saarland University, Inorganic Chemistry, Coordination Chemistry, Saarbrücken, Germany.
| | - Eckhard Bill
- Max Planck Institute for Chemical Energy Conversion, Mülheim an der Ruhr, Germany
| | - Karsten Meyer
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Department of Chemistry and Pharmacy, Inorganic Chemistry, Erlangen, Germany.
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3
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Mena A, Luna JR, MacGregor F, Landa EN, Metta-Magaña A, Lee WY, Fortier S. Photoinduced Cleavage of a Strained N-C Bond in an Iron Complex Supported by Super-Bulky Amidinate and Guanidinate Ligands. Inorg Chem 2024; 63:5351-5364. [PMID: 38481142 DOI: 10.1021/acs.inorgchem.3c03953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/26/2024]
Abstract
The reaction of Fe2(mes)4 with the super-bulky amidines and guanidines HLAr*-R (LAr*-R = [(Ar*N)2C(R)]-, Ar* = 2,6-bis(diphenylmethyl)-4-tert-butylphenyl), R = Me (LAr*-Me), tBu (LAr*-tBu), Ph (LAr*-Ph), NiPr2 (LAr*-iPr2N), and Pip (LAr*-Pip)) gives access to the three-coordinate iron-mesityl complexes (LAr*-R)Fe(mes) only where LAr*-R = LAr*-Me, LAr*-Ph, or LAr*-Pip. Subsequent protonolysis with the N-atom transfer reagent Hdbabh (Hdbabh = 2,3:5,6-dibenzo-7-azabicyclo[2.2.1]hepta-2,5-diene) is limited in success, providing in one instance a few crystals of four-coordinate (LAr*-Me)Fe(dbabh)(Hdbabh), while three-coordinate (LAr*-Pip)Fe(dbabh) is synthesized reproducibly. Complexes (LAr*-Me)Fe(dbabh)(Hdbabh) and (LAr*-Pip)Fe(dbabh) are thermally insensitive in solution to temperatures of up to 100 °C. On the other hand, both (LAr*-Me)Fe(dbabh)(Hdbabh) and (LAr*-Pip)Fe(dbabh) show sensitivity to blue LED light (395 nm), undergoing photochemical transformations. For instance, the photolysis of (LAr*-Me)Fe(dbabh)(Hdbabh) leads to N-C bond scission and C-C bond coupling across the -dbabh moieties to give four-coordinate (LAr*-Me)Fe(N=dbabh-dbabhNH2). Photolyzing pyridine-d5 (py-d5) solutions of (LAr*-Pip)Fe(dbabh) at -5 °C produces a new paramagnetic photoproduct, [P]. Due to the thermal sensitivity of compound [P], it has eluded structural characterization; yet, Evans' method measurements suggest that the iron(II) oxidation state is maintained, thereby pointing to the -dbabh moiety as the locus of chemical change. In line with this assessment, addition of excess Me3SiCl to solutions of [P] produces the iron(II) complex (LAr*-Pip)FeCl(py-d5) as shown by 1H NMR spectroscopy. Gas chromatography/mass spectrometry analysis of the solutions of [P] shows a peak in the chromatogram with a molecular mass corresponding to a formulation of C14H11N that cannot be attributed to Hdbabh. This provides evidence for the photochemical-induced isomerization of the -dbabh ligand, revealing a heretofore unknown photochemical sensitivity of this N atom transfer reagent.
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Affiliation(s)
- Asiel Mena
- Department of Chemistry and Biochemistry, University of Texas at El Paso, El Paso, Texas 79968, United States
| | - Juan R Luna
- Department of Chemistry and Biochemistry, University of Texas at El Paso, El Paso, Texas 79968, United States
| | - Frank MacGregor
- Department of Chemistry and Biochemistry, University of Texas at El Paso, El Paso, Texas 79968, United States
| | - Elizabeth Noriega Landa
- Department of Chemistry and Biochemistry, University of Texas at El Paso, El Paso, Texas 79968, United States
| | - Alejandro Metta-Magaña
- Department of Chemistry and Biochemistry, University of Texas at El Paso, El Paso, Texas 79968, United States
| | - Wen-Yee Lee
- Department of Chemistry and Biochemistry, University of Texas at El Paso, El Paso, Texas 79968, United States
| | - Skye Fortier
- Department of Chemistry and Biochemistry, University of Texas at El Paso, El Paso, Texas 79968, United States
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4
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Bhutto SM, Hooper RX, McWilliams SF, Mercado BQ, Holland PL. Iron(iv) alkyl complexes: electronic structure contributions to Fe-C bond homolysis and migration reactions that form N-C bonds from N 2. Chem Sci 2024; 15:3485-3494. [PMID: 38455018 PMCID: PMC10915813 DOI: 10.1039/d3sc05939a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 01/16/2024] [Indexed: 03/09/2024] Open
Abstract
High-valent iron alkyl complexes are rare, as they are prone to Fe-C bond homolysis. Here, we describe an unusual way to access formally iron(iv) alkyl complexes through double silylation of iron(i) alkyl dinitrogen complexes to form an NNSi2 group. Spectroscopically validated computations show that the disilylehydrazido(2-) ligand stabilizes the formal iron(iv) oxidation state through a strongly covalent Fe-N π-interaction, in which one π-bond fits an "inverted field" description. This means that the two bonding electrons are localized more on the metal than the ligand, and thus an iron(ii) resonance structure is a significant contributor, similar to the previously-reported phenyl analogue. However, in contrast to the phenyl complex which has an S = 1 ground state, the ground state of the alkyl complex is S = 2, which places one electron in the π* orbital, leading to longer and weaker Fe-N bonds. The reactivity of these hydrazido(2-) complexes is dependent on the steric and electronic properties of the specific alkyl group. When the alkyl group is the bulky trimethylsilylmethyl, the formally iron(iv) species is stable at room temperature and no migration of the alkyl ligand is observed. However, the analogous complex with the smaller methyl ligand does indeed undergo migration of the carbon-based ligand to the NNSi2 group to form a new N-C bond. This migration is followed by isomerization of the hydrazido ligand, and the product exists as two isomers that have distinct η1 and η2 binding of the hydrazido group. Lastly, when the alkyl group is benzyl, the Fe-C bond homolyzes to give a three-coordinate hydrazido(2-) complex which is likely due to the greater stability of a benzyl radical compared to that for methyl or trimethylsilylmethyl. These studies demonstrate the availability of a hydrocarbyl migration pathway at formally iron(iv) centers to form new N-C bonds directly to N2, though product selectivity is highly dependent on the identity of the migrating group.
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Affiliation(s)
- Samuel M Bhutto
- Department of Chemistry, Yale University New Haven Connecticut 06520 USA
| | - Reagan X Hooper
- Department of Chemistry, Yale University New Haven Connecticut 06520 USA
| | - Sean F McWilliams
- Department of Chemistry, Yale University New Haven Connecticut 06520 USA
| | - Brandon Q Mercado
- Department of Chemistry, Yale University New Haven Connecticut 06520 USA
| | - Patrick L Holland
- Department of Chemistry, Yale University New Haven Connecticut 06520 USA
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5
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Mahato S, VandeVen W, MacNeil GA, Pulfer JM, Storr T. Untangling ancillary ligand donation versus locus of oxidation effects on metal nitride reactivity. Chem Sci 2024; 15:2211-2220. [PMID: 38332824 PMCID: PMC10848731 DOI: 10.1039/d3sc05403a] [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: 10/12/2023] [Accepted: 01/01/2024] [Indexed: 02/10/2024] Open
Abstract
We detail the relative role of ancillary ligand electron-donating ability in comparison to the locus of oxidation (either metal or ligand) on the electrophilic reactivity of a series of oxidized Mn salen nitride complexes. The electron-donating ability of the ancillary salen ligand was tuned via the para-phenolate substituent (R = CF3, H, tBu, OiPr, NMe2, NEt2) in order to have minimal effect on the geometry at the metal center. Through a suite of experimental (electrochemistry, electron paramagnetic resonance spectroscopy, UV-vis-NIR spectroscopy) and theoretical (density functional theory) techniques, we have demonstrated that metal-based oxidation to [MnVI(SalR)N]+ occurs for R = CF3, H, tBu, OiPr, while ligand radical formation to [MnV(SalR)N]+˙ occurs with the more electron-donating substituents R = NMe2, NEt2. We next investigated the reactivity of the electrophilic nitride with triarylphosphines to form a MnIV phosphoraneiminato adduct and determined that the rate of reaction decreases as the electron-donating ability of the salen para-phenolate substituent is increased. Using a Hammett plot, we find a break in the Hammett relation between R = OiPr and R = NMe2, without a change in mechanism, consistent with the locus of oxidation exhibiting a dominant effect on nitride reactivity, and not the overall donating ability of the ancillary salen ligand. This work differentiates between the subtle and interconnected effects of ancillary ligand electron-donating ability, and locus of oxidation, on electrophilic nitride reactivity.
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Affiliation(s)
- Samyadeb Mahato
- Department of Chemistry, Simon Fraser University Burnaby British Columbia V5A 1S6 Canada
| | - Warren VandeVen
- Department of Chemistry, Simon Fraser University Burnaby British Columbia V5A 1S6 Canada
| | - Gregory A MacNeil
- Department of Chemistry, Simon Fraser University Burnaby British Columbia V5A 1S6 Canada
| | - Jason M Pulfer
- Department of Chemistry, Simon Fraser University Burnaby British Columbia V5A 1S6 Canada
| | - Tim Storr
- Department of Chemistry, Simon Fraser University Burnaby British Columbia V5A 1S6 Canada
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6
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Acosta CM, Belov DS, Lamur AH, Brantley CL, Solans-Monfort X, Rue KL, Christou G, Bukhryakov KV. Mononuclear Four-Coordinate Bis-Fluoride Bis-NHC Complexes of Chromium(II), Iron(II), and Cobalt(II). Inorg Chem 2023; 62:18108-18115. [PMID: 37876243 DOI: 10.1021/acs.inorgchem.3c02442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
Abstract
The reaction between silylamido complexes of Cr(II), Fe(II), and Co(II) and IMes·2HF salt in the presence of IMes (IMes = 1,3-dimesitylimidazol-2-ylidene) led to isolation of Cr(IMes)2F2 (2-Cr), Fe(IMes)2F2 (2-Fe), and Co(IMes)2F2 (2-Co). X-ray structural studies revealed that 2-Cr adopts square planar geometry, while 2-Fe and 2-Co have distorted tetrahedral geometry. Magnetic susceptibility studies of 2-Cr, 2-Fe, and 2-Co were consistent with high-spin complexes, S = 2 for 2-Cr/2-Fe and S = 3/2 for 2-Co. We demonstrated that fluoride can be successfully exchanged for cyanide and azide using trimethylsilyl cyanide and trimethylsilyl azide (3-Fe and 4-Fe). DFT studies suggest that the preference of 2-Cr to adopt square planar geometry over tetrahedral is due to its d4 metal center, where four electrons fill the lower-lying d-orbitals.
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Affiliation(s)
- Carlos M Acosta
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - Dmitry S Belov
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - Andy H Lamur
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - ChristiAnna L Brantley
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
| | | | - Kelly L Rue
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - George Christou
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
| | - Konstantin V Bukhryakov
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
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7
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Palomero OE, Jones RA. Hyperbulky 1,1’-dicarbodiimidoferrocene proligand promotes an asymmetric guanidinate coordination in a Zr(IV) complex. Polyhedron 2023. [DOI: 10.1016/j.poly.2023.116340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
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8
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Keilwerth M, Mao W, Jannuzzi SAV, Grunwald L, Heinemann FW, Scheurer A, Sutter J, DeBeer S, Munz D, Meyer K. From Divalent to Pentavalent Iron Imido Complexes and an Fe(V) Nitride via N-C Bond Cleavage. J Am Chem Soc 2023; 145:873-887. [PMID: 36583993 DOI: 10.1021/jacs.2c09072] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
As key intermediates in metal-catalyzed nitrogen-transfer chemistry, terminal imido complexes of iron have attracted significant attention for a long time. In search of versatile model compounds, the recently developed second-generation N-anchored tris-NHC chelating ligand tris-[2-(3-mesityl-imidazole-2-ylidene)-methyl]amine (TIMMNMes) was utilized to synthesize and compare two series of mid- to high-valent iron alkyl imido complexes, including a reactive Fe(V) adamantyl imido intermediate en route to an isolable Fe(V) nitrido complex. The chemistry toward the iron adamantyl imides was achieved by reacting the Fe(I) precursor [(TIMMNMes)FeI(N2)]+ (1) with 1-adamantyl azide to yield the corresponding trivalent iron imide. Stepwise chemical reduction and oxidation lead to the isostructural series of low-spin [(TIMMNMes)Fe(NAd)]0,1+,2+,3+ (2Ad-5Ad) in oxidation states II to V. The Fe(V) imide [(TIMMNMes)Fe(NAd)]3+ (5Ad) is unstable under ambient conditions and converts to the air-stable nitride [(TIMMNMes)FeV(N)]2+ (6) via N-C bond cleavage. The stability of the pentavalent imide can be increased by derivatizing the nitride [(TIMMNMes)FeIV(N)]+ (7) with an ethyl group using the triethyloxonium salt Et3OPF6. This gives access to the analogous series of ethyl imides [(TIMMNMes)Fe(NEt)]0,1+,2+,3+ (2Et-5Et), including the stable Fe(V) ethyl imide. Iron imido complexes exist in a manifold of different electronic structures, ultimately controlling their diverse reactivities. Accordingly, these complexes were characterized by single-crystal X-ray diffraction analyses, SQUID magnetization, and electrochemical methods, as well as 57Fe Mössbauer, IR vibrational, UV/vis electronic absorption, multinuclear NMR, X-band EPR, and X-ray absorption spectroscopy. Our studies are complemented with quantum chemical calculations, thus providing further insight into the electronic structures of all complexes.
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Affiliation(s)
- Martin Keilwerth
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany
| | - Weiqing Mao
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany
| | - Sergio A V Jannuzzi
- Max-Planck-Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Liam Grunwald
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany.,Department of Chemistry and Applied Biosciences (D-CHAB), ETH Zürich, 8093 Zürich, Switzerland
| | - Frank W Heinemann
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany
| | - Andreas Scheurer
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany
| | - Jörg Sutter
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany
| | - Serena DeBeer
- Max-Planck-Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Dominik Munz
- Inorganic Chemistry: Coordination Chemistry, Saarland University, Campus C4 1, 66123 Saarbrücken, Germany
| | - Karsten Meyer
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany
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9
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Schild DJ, Nurdin L, Moret ME, Oyala PH, Peters JC. Characterization of a Proposed Terminal Iron(III) Nitride Intermediate of Nitrogen Fixation Stabilized by a Trisphosphine-Borane Ligand. Angew Chem Int Ed Engl 2022; 61:e202209655. [PMID: 35973965 PMCID: PMC9588675 DOI: 10.1002/anie.202209655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Indexed: 11/11/2022]
Abstract
Terminal iron nitrides (Fe≡N) have been proposed as intermediates of Fe-mediated nitrogen fixation, and well-defined synthetic iron nitrides have been characterized in high oxidation states, including FeIV , FeV , and FeVI . This study reports the generation and low temperature characterization of a terminally bound iron(III) nitride, P3 B Fe(N) (P3 B =tris(o-diisopropylphosphinophenyl)borane), which is a proposed intermediate of iron-mediated nitrogen fixation by the P3 B Fe-catalyst system. CW- and pulse EPR spectroscopy (HYSCORE and ENDOR), supported by DFT calculations, help to define a 2 A ground state electronic structure of this C3 -symmetric nitride species, placing the unpaired spin in a sigma orbital along the B-Fe-N vector; this electronic structure is distinct for an iron nitride. The unusual d5 -configuration is stabilized by significant delocalization (≈50 %) of the unpaired electron onto the axial boron and nitrogen ligands, with a majority of the spin residing on boron.
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Affiliation(s)
- Dirk J Schild
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Lucie Nurdin
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Marc-Etienne Moret
- Current address: Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht, The Netherlands
| | - 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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10
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Schild DJ, Nurdin L, Moret ME, Oyala PH, Peters J. Characterization of a Proposed Terminal Iron(III) Nitride Intermediate of Nitrogen Fixation Stabilized by a Trisphosphine‐Borane Ligand. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202209655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Dirk J Schild
- California Institute of Technology Chemistry UNITED STATES
| | - Lucie Nurdin
- California Institute of Technology Chemistry UNITED STATES
| | | | - Paul H Oyala
- California Institute of Technology Chemistry UNITED STATES
| | - Jonas Peters
- California Institute of Technology Division of Chemistry and Chemical Engineering 1200 East California Blvd 91103 Pasadena UNITED STATES
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11
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Martelino D, Mahato S, VandeVen W, Hein NM, Clarke RM, MacNeil GA, Thomas F, Storr T. Chromium Nitride Umpolung Tuned by the Locus of Oxidation. J Am Chem Soc 2022; 144:11594-11607. [PMID: 35749669 DOI: 10.1021/jacs.2c01840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Oxidation of a series of CrV nitride salen complexes (CrVNSalR) with different para-phenolate substituents (R = CF3, tBu, NMe2) was investigated to determine how the locus of oxidation (either metal or ligand) dictates reactivity at the nitride. Para-phenolate substituents were chosen to provide maximum variation in the electron-donating ability of the tetradentate ligand at a site remote from the metal coordination sphere. We show that one-electron oxidation affords CrVI nitrides ([CrVINSalR]+; R = CF3, tBu) and a localized CrV nitride phenoxyl radical for the more electron-donating NMe2 substituent ([CrVNSalNMe2]•+). The facile nitride homocoupling observed for the MnVI analogues was significantly attenuated for the CrVI complexes due to a smaller increase in nitride character in the M≡N π* orbitals for Cr relative to Mn. Upon oxidation, both the calculated nitride natural population analysis (NPA) charge and energy of molecular orbitals associated with the {Cr≡N} unit change to a lesser extent for the CrV ligand radical derivative ([CrVNSalNMe2]•+) in comparison to the CrVI derivatives ([CrVINSalR]+; R = CF3, tBu). As a result, [CrVNSalNMe2]•+ reacts with B(C6F5)3, thus exhibiting similar nucleophilic reactivity to the neutral CrV nitride derivatives. In contrast, the CrVI derivatives ([CrVINSalR]+; R = CF3, tBu) act as electrophiles, displaying facile reactivity with PPh3 and no reaction with B(C6F5)3. Thus, while oxidation to the ligand radical does not change the reactivity profile, metal-based oxidation to CrVI results in umpolung, a switch from nucleophilic to electrophilic reactivity at the terminal nitride.
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Affiliation(s)
- Diego Martelino
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Samyadeb Mahato
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Warren VandeVen
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Nicholas M Hein
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Ryan M Clarke
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Gregory A MacNeil
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Fabrice Thomas
- Univ. Grenoble Alpes, CNRS, DCM, F-38000 Grenoble, France
| | - Tim Storr
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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12
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Hobson K, Carmalt CJ, Bakewell C. Aluminum Amidinates: Insights into Alkyne Hydroboration. Inorg Chem 2021; 60:10958-10969. [PMID: 34270214 PMCID: PMC8388121 DOI: 10.1021/acs.inorgchem.1c00619] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Indexed: 11/30/2022]
Abstract
The mechanism of the aluminum-mediated hydroboration of terminal alkynes was investigated using a series of novel aluminum amidinate hydride and alkyl complexes bearing symmetric and asymmetric ligands. The new aluminum complexes were fully characterized and found to facilitate the formation of the (E)-vinylboronate hydroboration product, with rates and orders of reaction linked to complex size and stability. Kinetic analysis and stoichiometric reactions were used to elucidate the mechanism, which we propose to proceed via the initial formation of an Al-borane adduct. Additionally, the most unstable complex was found to promote decomposition of the pinacolborane substrate to borane (BH3), which can then proceed to catalyze the reaction. This mechanism is in contrast to previously reported aluminum hydride-catalyzed hydroboration reactions, which are proposed to proceed via the initial formation of an aluminum acetylide, or by hydroalumination to form a vinylboronate ester as the first step in the catalytic cycle.
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Affiliation(s)
- Katie Hobson
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Claire J. Carmalt
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Clare Bakewell
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
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13
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Wang H, Wu L, Zheng B, Du L, To W, Ko C, Phillips DL, Che C. C−H Activation by an Iron‐Nitrido Bis‐Pocket Porphyrin Species. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202014191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Hai‐Xu Wang
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry The University of Hong Kong Pokfulam Road Hong Kong China
| | - Liangliang Wu
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry The University of Hong Kong Pokfulam Road Hong Kong China
| | - Bin Zheng
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry The University of Hong Kong Pokfulam Road Hong Kong China
| | - Lili Du
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry The University of Hong Kong Pokfulam Road Hong Kong China
| | - Wai‐Pong To
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry The University of Hong Kong Pokfulam Road Hong Kong China
| | - Cheng‐Hoi Ko
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry The University of Hong Kong Pokfulam Road Hong Kong China
| | - David Lee Phillips
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry The University of Hong Kong Pokfulam Road Hong Kong China
| | - Chi‐Ming Che
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry The University of Hong Kong Pokfulam Road Hong Kong China
- HKU Shenzhen Institute of Research & Innovation Shenzhen China
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14
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Wang HX, Wu L, Zheng B, Du L, To WP, Ko CH, Phillips DL, Che CM. C-H Activation by an Iron-Nitrido Bis-Pocket Porphyrin Species. Angew Chem Int Ed Engl 2021; 60:4796-4803. [PMID: 33205509 DOI: 10.1002/anie.202014191] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 11/16/2020] [Indexed: 12/11/2022]
Abstract
High-valent iron-nitrido species are nitrogen analogues of iron-oxo species which are versatile reagents for C-H oxidation. Nonetheless, C-H activation by iron-nitrido species has been scarcely explored, as this is often hampered by their instability and short lifetime in solutions. Herein, the hydrogen atom transfer (HAT) reactivity of an Fe porphyrin nitrido species (2 c) toward C-H substrates was studied in solutions at room temperature, which was achieved by nanosecond laser flash photolysis (LFP) of its FeIII -azido precursor (1 c) supported by a bulky bis-pocket porphyrin ligand. C-H bonds with bond dissociation enthalpies (BDEs) of up to ≈84 kcal mol-1 could be activated, and the second-order rate constants (k2 ) are on the order of 102 -104 s-1 m-1 . The Fe-amido product formed after HAT could further release ammonia upon protonation.
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Affiliation(s)
- Hai-Xu Wang
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Liangliang Wu
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Bin Zheng
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Lili Du
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Wai-Pong To
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Cheng-Hoi Ko
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - David Lee Phillips
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Chi-Ming Che
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China.,HKU Shenzhen Institute of Research & Innovation, Shenzhen, China
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15
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Keilwerth M, Grunwald L, Mao W, Heinemann FW, Sutter J, Bill E, Meyer K. Ligand Tailoring Toward an Air-Stable Iron(V) Nitrido Complex. J Am Chem Soc 2021; 143:1458-1465. [PMID: 33430587 DOI: 10.1021/jacs.0c11141] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A new supporting ligand, tris-[2-(3-mesityl-imidazol-2-ylidene)methyl]amine (TIMMNMes), was developed and utilized to isolate an air-stable iron(V) complex bearing a terminal nitrido ligand, which was synthesized by one-electron oxidation from the iron(IV) precursor. Single-crystal X-ray diffraction analyses of both complexes reveal that the metal-centered oxidation is escorted by iron nitride (Fe≡N) bond elongation, which in turn is accompanied by the accommodation of the high-valence iron center closer to the equatorial plane of a trigonal bipyramid. This contrasts with the previous observation of the only other literature-known Fe(IV)≡N/Fe(V)≡N redox pair, namely, [PhB(tBuIm)3FeN]0/+. On the basis of 57Fe Mössbauer, EPR, and UV/vis electronic absorption spectroscopy as well as quantum chemical calculations, we identified the lesser degree of pyramidalization around the iron atom, the Jahn-Teller distortion, and the resulting nature of the SOMO to be the decisive factors at play.
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Affiliation(s)
- Martin Keilwerth
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany
| | - Liam Grunwald
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany
| | - Weiqing Mao
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany
| | - Frank W Heinemann
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany
| | - Jörg Sutter
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany
| | - Eckhard Bill
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Karsten Meyer
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Egerlandstraße 1, 91058 Erlangen, Germany
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16
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Andris E, Segers K, Mehara J, Rulíšek L, Roithová J. Closed Shell Iron(IV) Oxo Complex with an Fe–O Triple Bond: Computational Design, Synthesis, and Reactivity. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202009347] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Erik Andris
- Institute for Molecules and Materials Radboud University Heyendaalseweg 135 6525 AJ Nijmegen The Netherlands
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences Flemingovo náměstí 2 16610 Praha 6 Czech Republic
| | - Koen Segers
- Institute for Molecules and Materials Radboud University Heyendaalseweg 135 6525 AJ Nijmegen The Netherlands
| | - Jaya Mehara
- Institute for Molecules and Materials Radboud University Heyendaalseweg 135 6525 AJ Nijmegen The Netherlands
| | - Lubomír Rulíšek
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences Flemingovo náměstí 2 16610 Praha 6 Czech Republic
| | - Jana Roithová
- Institute for Molecules and Materials Radboud University Heyendaalseweg 135 6525 AJ Nijmegen The Netherlands
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17
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Andris E, Segers K, Mehara J, Rulíšek L, Roithová J. Closed Shell Iron(IV) Oxo Complex with an Fe-O Triple Bond: Computational Design, Synthesis, and Reactivity. Angew Chem Int Ed Engl 2020; 59:23137-23144. [PMID: 32926539 PMCID: PMC7756500 DOI: 10.1002/anie.202009347] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Indexed: 12/11/2022]
Abstract
Iron(IV)-oxo intermediates in nature contain two unpaired electrons in the Fe-O antibonding orbitals, which are thought to contribute to their high reactivity. To challenge this hypothesis, we designed and synthesized closed-shell singlet iron(IV) oxo complex [(quinisox)Fe(O)]+ (1+ ; quinisox-H=(N-(2-(2-isoxazoline-3-yl)phenyl)quinoline-8-carboxamide). We identified the quinisox ligand by DFT computational screening out of over 450 candidates. After the ligand synthesis, we detected 1+ in the gas phase and confirmed its spin state by visible and infrared photodissociation spectroscopy (IRPD). The Fe-O stretching frequency in 1+ is 960.5 cm-1 , consistent with an Fe-O triple bond, which was also confirmed by multireference calculations. The unprecedented bond strength is accompanied by high gas-phase reactivity of 1+ in oxygen atom transfer (OAT) and in proton-coupled electron transfer reactions. This challenges the current view of the spin-state driven reactivity of the Fe-O complexes.
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Affiliation(s)
- Erik Andris
- Institute for Molecules and MaterialsRadboud UniversityHeyendaalseweg 1356525 AJNijmegenThe Netherlands
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of SciencesFlemingovo náměstí 216610Praha 6Czech Republic
| | - Koen Segers
- Institute for Molecules and MaterialsRadboud UniversityHeyendaalseweg 1356525 AJNijmegenThe Netherlands
| | - Jaya Mehara
- Institute for Molecules and MaterialsRadboud UniversityHeyendaalseweg 1356525 AJNijmegenThe Netherlands
| | - Lubomír Rulíšek
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of SciencesFlemingovo náměstí 216610Praha 6Czech Republic
| | - Jana Roithová
- Institute for Molecules and MaterialsRadboud UniversityHeyendaalseweg 1356525 AJNijmegenThe Netherlands
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18
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Aguirre Quintana LM, Jiang N, Bacsa J, La Pierre HS. Homoleptic cerium tris(dialkylamido)imidophosphorane guanidinate complexes. Dalton Trans 2020; 49:14908-14913. [PMID: 33078808 DOI: 10.1039/d0dt03472j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
We report the synthesis of a new potassium tris(piperdino)imidophosphorane N,N'-dicyclohexylguanidinate, K[CyGNP(pip)3], and describe the synthesis and characterization of the tris-homoleptic compounds, [Ce(CyGNP(pip)3)3], 1-Ce, and [Ce(CyGNP(pip)3)3][BPh4], 2-Ce. The latter is an unusual cationic tetravalent cerium complex. Cyclic voltammetry studies of 1-Ce and 2-Ce revealed Epc potentials of -1.56 V and -1.81 V, and Epa potentials of -0.78 V and -0.66 V (200 mV s-1; THF, vs. Fc0/+), respectively. Compounds 1-Ce and 2-Ce were studied by L3-edge X-ray absorption near-edge spectroscopy (XANES), and the fit of the spectrum of 2-Ce revealed a white-line multiplet with an nf value of 0.50(2).
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Affiliation(s)
- Luis M Aguirre Quintana
- Department of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA.
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19
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Prakash O, Chábera P, Rosemann NW, Huang P, Häggström L, Ericsson T, Strand D, Persson P, Bendix J, Lomoth R, Wärnmark K. A Stable Homoleptic Organometallic Iron(IV) Complex. Chemistry 2020; 26:12728-12732. [PMID: 32369645 PMCID: PMC7590184 DOI: 10.1002/chem.202002158] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Indexed: 11/08/2022]
Abstract
A homoleptic organometallic FeIV complex that is stable in both solution and in the solid state at ambient conditions has been synthesized and isolated as [Fe(phtmeimb)2 ](PF6 )2 (phtmeimb=[phenyl(tris(3-methylimidazolin-2-ylidene))borate]- ). This FeIV N-heterocyclic carbene (NHC) complex was characterized by 1 H NMR, HR-MS, elemental analysis, scXRD analysis, electrochemistry, Mößbauer spectroscopy, and magnetic susceptibility. The two latter techniques unequivocally demonstrate that [Fe(phtmeimb)2 ](PF6 )2 is a triplet FeIV low-spin S=1 complex in the ground state, in agreement with quantum chemical calculations. The electronic absorption spectrum of [Fe(phtmeimb)2 ](PF6 )2 in acetonitrile shows an intense absorption band in the red and near IR, due to LMCT (ligand-to-metal charge transfer) excitation. For the first time the excited state dynamics of a FeIV complex was studied and revealed a ≈0.8 ps lifetime of the 3 LMCT excited state of [Fe(phtmeimb)2 ](PF6 )2 in acetonitrile.
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Affiliation(s)
- Om Prakash
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, Lund, 22100, Sweden
| | - Pavel Chábera
- Division of Chemical Physics, Department of Chemistry, Lund University, Box 124, Lund, 22100, Sweden
| | - Nils W Rosemann
- Division of Chemical Physics, Department of Chemistry, Lund University, Box 124, Lund, 22100, Sweden
| | - Ping Huang
- Department of Chemistry, Ångström Laboratory, Uppsala University, Box 523, Uppsala, 75120, Sweden
| | - Lennart Häggström
- Department of Physics, Ångström Laboratory, Uppsala University, Box 528, Uppsala, 751 21, Sweden
| | - Tore Ericsson
- Department of Physics, Ångström Laboratory, Uppsala University, Box 528, Uppsala, 751 21, Sweden
| | - Daniel Strand
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, Lund, 22100, Sweden
| | - Petter Persson
- Theoretical Chemistry Division, Department of Chemistry, Lund University, Box 124, Lund, 22100, Sweden
| | - Jesper Bendix
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen, Denmark
| | - Reiner Lomoth
- Department of Chemistry, Ångström Laboratory, Uppsala University, Box 523, Uppsala, 75120, Sweden
| | - Kenneth Wärnmark
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, Lund, 22100, Sweden
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20
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Zhang S, Cui P, Liu T, Wang Q, Longo TJ, Thierer LM, Manor BC, Gau MR, Carroll PJ, Papaefthymiou GC, Tomson NC. N-H Bond Formation at a Diiron Bridging Nitride. Angew Chem Int Ed Engl 2020; 59:15215-15219. [PMID: 32441448 PMCID: PMC7680347 DOI: 10.1002/anie.202006391] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Indexed: 01/07/2023]
Abstract
Despite their connection to ammonia synthesis, little is known about the ability of iron-bound, bridging nitrides to form N-H bonds. Herein we report a linear diiron bridging nitride complex supported by a redox-active macrocycle. The unique ability of the ligand scaffold to adapt to the geometric preference of the bridging species was found to facilitate the formation of N-H bonds via proton-coupled electron transfer to generate a μ-amide product. The structurally analogous μ-silyl- and μ-borylamide complexes were shown to form from the net insertion of the nitride into the E-H bonds (E=B, Si). Protonation of the parent bridging amide produced ammonia in high yield, and treatment of the nitride with PhSH was found to liberate NH3 in high yield through a reaction that engages the redox-activity of the ligand during PCET.
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Affiliation(s)
- Shaoguang Zhang
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA, 19104, USA
| | - Peng Cui
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA, 19104, USA
| | - Tianchang Liu
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA, 19104, USA
| | - Qiuran Wang
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA, 19104, USA
| | - Thomas J Longo
- Department of Physics, Villanova University, Villanova, PA, 19085, USA
| | - Laura M Thierer
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA, 19104, USA
| | - Brian C Manor
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA, 19104, USA
| | - Michael R Gau
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA, 19104, USA
| | - Patrick J Carroll
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA, 19104, USA
| | | | - Neil C Tomson
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, PA, 19104, USA
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21
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Zhang S, Cui P, Liu T, Wang Q, Longo TJ, Thierer LM, Manor BC, Gau MR, Carroll PJ, Papaefthymiou GC, Tomson NC. N−H Bond Formation at a Diiron Bridging Nitride. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202006391] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Shaoguang Zhang
- P. Roy and Diana T. Vagelos Laboratories Department of Chemistry University of Pennsylvania 231 South 34th Street Philadelphia PA 19104 USA
| | - Peng Cui
- P. Roy and Diana T. Vagelos Laboratories Department of Chemistry University of Pennsylvania 231 South 34th Street Philadelphia PA 19104 USA
| | - Tianchang Liu
- P. Roy and Diana T. Vagelos Laboratories Department of Chemistry University of Pennsylvania 231 South 34th Street Philadelphia PA 19104 USA
| | - Qiuran Wang
- P. Roy and Diana T. Vagelos Laboratories Department of Chemistry University of Pennsylvania 231 South 34th Street Philadelphia PA 19104 USA
| | - Thomas J. Longo
- Department of Physics Villanova University Villanova PA 19085 USA
| | - Laura M. Thierer
- P. Roy and Diana T. Vagelos Laboratories Department of Chemistry University of Pennsylvania 231 South 34th Street Philadelphia PA 19104 USA
| | - Brian C. Manor
- P. Roy and Diana T. Vagelos Laboratories Department of Chemistry University of Pennsylvania 231 South 34th Street Philadelphia PA 19104 USA
| | - Michael R. Gau
- P. Roy and Diana T. Vagelos Laboratories Department of Chemistry University of Pennsylvania 231 South 34th Street Philadelphia PA 19104 USA
| | - Patrick J. Carroll
- P. Roy and Diana T. Vagelos Laboratories Department of Chemistry University of Pennsylvania 231 South 34th Street Philadelphia PA 19104 USA
| | | | - Neil C. Tomson
- P. Roy and Diana T. Vagelos Laboratories Department of Chemistry University of Pennsylvania 231 South 34th Street Philadelphia PA 19104 USA
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22
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Bakewell C. Magnesium hydrides bearing sterically demanding amidinate ligands: synthesis, reactivity and catalytic application. Dalton Trans 2020; 49:11354-11360. [PMID: 32766619 DOI: 10.1039/d0dt02523b] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The synthesis and characterisation of a series of magnesium complexes bearing sterically demanding amidinate ligands is reported; this includes magneisum amides (1a and 1b), hydrides (3a and 3b) and alkyl complexes (2b). The solid and solution state behaviour of the complexes has been investigated using single crystal X-ray diffraction and NMR spectroscopy, revealing the magnesium hydrides to exist as dimers in the solid state, dispite the sterically demanding ligand systems and showing a degree of monomeric character in solution. The stoichiometric and catalytic activity of the amidinate complexes were investigated, with the complexes found to efficiently mediate both the hydroamination of N,N'-diisopropylcarbodiimide and the Tishchenko reaction. The metal hydrides are highly reactive towards coordinating substrates, showing a significant increase in catalytic rate compared with more ubiquitous β-diketiminate magnesium hydrides.
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Affiliation(s)
- Clare Bakewell
- University College London, Department of Chemistry, 20 Gordon Street, London WC1H 0AJ, UK.
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23
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Sengupta D, Sandoval-Pauker C, Schueller E, Encerrado-Manriquez AM, Metta-Magaña A, Lee WY, Seshadri R, Pinter B, Fortier S. Isolation of a Bimetallic Cobalt(III) Nitride and Examination of Its Hydrogen Atom Abstraction Chemistry and Reactivity toward H 2. J Am Chem Soc 2020; 142:8233-8242. [PMID: 32279486 DOI: 10.1021/jacs.0c00291] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Room temperature photolysis of the bis(azide)cobaltate(II) complex [Na(THF)x][(ketguan)Co(N3)2] (ketguan = [(tBu2CN)C(NDipp)2]-, Dipp = 2,6-diisopropylphenyl) (3a) in THF cleanly forms the binuclear cobalt nitride Na(THF)4{[(ketguan)Co(N3)]2(μ-N)} (1). Compound 1 represents the first example of an isolable, bimetallic cobalt nitride complex, and it has been fully characterized by spectroscopic, magnetic, and computational analyses. Density functional theory supports a CoIII═N═CoIII canonical form with significant π-bonding between the cobalt centers and the nitride atom. Unlike other group 9 bridging nitride complexes, no radical character is detected at the bridging N atom of 1. Indeed, 1 is unreactive toward weak C-H donors and even cocrystallizes with a molecule of cyclohexadiene (CHD) in its crystallographic unit cell to give 1·CHD as a room temperature stable product. Notably, addition of pyridine to 1 or photolyzed solutions of [(ketguan)Co(N3)(py)]2 (4a) leads to destabilization via activation of the nitride unit, resulting in the mixed-valent Co(II)/Co(III) bridged imido species [(ketguan)Co(py)][(ketguan)Co](μ-NH)(μ-N3) (5) formed from intermolecular hydrogen atom abstraction (HAA) of strong C-H bonds (BDE ∼ 100 kcal/mol). Kinetic rate analysis of the formation of 5 in the presence of C6H12 or C6D12 gives a KIE = 2.5 ± 0.1, supportive of a HAA formation pathway. The reactivity of our system was further probed by photolyzing benzene/pyridine solutions of 4a under H2 and D2 atmospheres (150 psi), which leads to the exclusive formation of the bis(imido) complexes [(ketguan)Co(μ-NH)]2 (6) and [(ketguan)Co(μ-ND)]2 (6-D), respectively, as a result of dihydrogen activation. These results provide unique insights into the chemistry and electronic structure of late 3d metal nitrides while providing entryway into C-H activation pathways.
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Affiliation(s)
- Debabrata Sengupta
- Department of Chemistry and Biochemistry, University of Texas at El Paso, El Paso, Texas 79968, United States
| | | | - Emily Schueller
- Materials Department and Materials Research Laboratory, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | | | - Alejandro Metta-Magaña
- Department of Chemistry and Biochemistry, University of Texas at El Paso, El Paso, Texas 79968, United States
| | - Wen-Yee Lee
- Department of Chemistry and Biochemistry, University of Texas at El Paso, El Paso, Texas 79968, United States
| | - Ram Seshadri
- Materials Department and Materials Research Laboratory, University of California, Santa Barbara, Santa Barbara, California 93106, United States.,Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Balazs Pinter
- Department of Chemistry, Universidad Técnica Federico Santa María, Valparaíso 2390123, Chile
| | - Skye Fortier
- Department of Chemistry and Biochemistry, University of Texas at El Paso, El Paso, Texas 79968, United States
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24
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Yadav M, Metta-Magaña A, Fortier S. Intra- and intermolecular interception of a photochemically generated terminal uranium nitride. Chem Sci 2020; 11:2381-2387. [PMID: 34084400 PMCID: PMC8157337 DOI: 10.1039/c9sc05992j] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The photochemically generated synthesis of a terminal uranium nitride species is here reported and an examination of its intra- and intermolecular chemistry is presented. Treatment of the U(iii) complex LArUI(DME) ((LAr)2− = 2,2′′-bis(Dippanilide)-p-terphenyl; Dipp = 2,6-diisopropylphenyl) with LiNImDipp ((NImDipp)− = 1,3-bis(Dipp)-imidazolin-2-iminato) generates the sterically congested 3N-coordinate compound LArU(NImDipp) (1). Complex 1 reacts with 1 equiv. of Ph3CN3 to give the U(iv) azide LArU(N3)(NImDipp) (2). Structural analysis of 2 reveals inequivalent Nα–Nβ > Nβ–Nγ distances indicative of an activated azide moiety predisposed to N2 loss. Room-temperature photolysis of benzene solutions of 2 affords the U(iv) amide (N-LAr)U(NImDipp) (3) via intramolecular N-atom insertion into the benzylic C–H bond of a pendant isopropyl group of the (LAr)2− ligand. The formation of 3 occurs as a result of the intramolecular interception of the intermediately generated, terminal uranium nitride (LAr)U(N)(NImDipp) (3′). Evidence for the formation of 3′ is further bolstered by its intermolecular capture, accomplished by photolyzing solutions of 2 in the presence of an isocyanide or PMe3 to give (LAr)U[NCN(C6H3Me2)](NImDipp) (5) and (N,C-LAr*)U(N
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PMe3)(NImDipp) (6), respectively. These results expand upon the limited reactivity studies of terminal uranium–nitride moieties and provide new insights into their chemical properties. Photolysis of the U(iv) azide LArU(NImDipp) generates a reactive uranium nitride intermediate that can be intercepted by nucleophilic substrates – the first example of intermolecular chemistry of a rare photochemically generated uranium nitride.![]()
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Affiliation(s)
- Munendra Yadav
- Department of Chemistry and Biochemistry, University of Texas at El Paso El Paso TX 79968 USA
| | - Alejandro Metta-Magaña
- Department of Chemistry and Biochemistry, University of Texas at El Paso El Paso TX 79968 USA
| | - Skye Fortier
- Department of Chemistry and Biochemistry, University of Texas at El Paso El Paso TX 79968 USA
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25
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Valdez-Moreira JA, Millikan SP, Gao X, Carta V, Chen CH, Smith JM. Hydrosilylation of an Iron(IV) Nitride Complex. Inorg Chem 2020; 59:579-583. [PMID: 31876412 DOI: 10.1021/acs.inorgchem.9b02831] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The nitride ligand in iron(IV) complex PhB(MesIm)3Fe≡N reacts with excess H3SiPh to afford PhB(MesIm)3Fe(μ-H)3(SiHPh) as the major product, which has been structurally and spectroscopically characterized. Bulkier silane HaSiPh2 provides iron(II) amido complex PhB(MesIm)3FeN(H)(SiHPh2) as the initial product of the reaction, with excess H2SiPh2 affording diamagnetic PhB(MesIm)3Fe(μ-H)3(SiPh2) as the major product. Unobserved iron(II) hydride PhB(MesIm)3Fe-H is implicated as an intermediate in this reaction, as suggested by the results of the reaction between iron(II) amido PhB(MesIm)3FeN(H)tBu and H3SiPh, which provides PhB(MesIm)3Fe(H)(μ-H)2(Si(NHtBu)Ph) as the sole product.
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Affiliation(s)
- Juan A Valdez-Moreira
- Department of Chemistry , Indiana University , 800 E. Kirkwood Avenue , Bloomington , Indiana 47405 , United States
| | - Sean P Millikan
- Department of Chemistry , Indiana University , 800 E. Kirkwood Avenue , Bloomington , Indiana 47405 , United States
| | - Xinfeng Gao
- Department of Chemistry , Indiana University , 800 E. Kirkwood Avenue , Bloomington , Indiana 47405 , United States
| | - Veronica Carta
- Department of Chemistry , Indiana University , 800 E. Kirkwood Avenue , Bloomington , Indiana 47405 , United States
| | - Chun-Hsing Chen
- Department of Chemistry , Indiana University , 800 E. Kirkwood Avenue , Bloomington , Indiana 47405 , United States
| | - Jeremy M Smith
- Department of Chemistry , Indiana University , 800 E. Kirkwood Avenue , Bloomington , Indiana 47405 , United States
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26
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Chang HC, Lin YH, Werlé C, Neese F, Lee WZ, Bill E, Ye S. Conversion of a Fleeting Open-Shell Iron Nitride into an Iron Nitrosyl. Angew Chem Int Ed Engl 2019; 58:17589-17593. [PMID: 31532866 PMCID: PMC6899486 DOI: 10.1002/anie.201908689] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 09/10/2019] [Indexed: 11/12/2022]
Abstract
Terminal metal nitrides have been proposed as key intermediates in a series of pivotal chemical transformations. However, exploring the chemical activity of transient tetragonal iron(V) nitrides is largely impeded by their facile dimerization in fluid solutions. Herein, in situ EPR and Mössbauer investigations are presented of unprecedented oxygenation of a paramagnetic iron(V) nitrido intermediate, [FeVN(cyclam‐ac)]+ (2, cyclam‐ac−=1,4,8,11‐tetraazacyclotetradecane‐1‐acetate anion), yielding an iron nitrosyl complex, [Fe(NO)(cyclam‐ac)]+ (3). Further theoretical studies suggest that during the reaction a closed‐shell singlet O atom is transferred to 2. Consequently, the N−O bond formation does not follow a radical coupling mechanism proposed for the N−N bond formation but is accomplished by three mutual electron‐transfer pathways between 2 and the O atom donor, thanks to the ambiphilic nature of 2.
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Affiliation(s)
- Hao-Ching Chang
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Yen-Hao Lin
- Department of Chemistry, National Taiwan Normal University, 88, Ting-chou Rd. Sec. 4, 11677, Taipei, Taiwan
| | - Christophe Werlé
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, 45470, Mülheim an der Ruhr, Germany
| | - Frank Neese
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Way-Zen Lee
- Department of Chemistry, National Taiwan Normal University, 88, Ting-chou Rd. Sec. 4, 11677, Taipei, Taiwan.,Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100, Shi-Chuan 1st Rd., 807, Kaohsiung, Taiwan
| | - Eckhard Bill
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, 45470, Mülheim an der Ruhr, Germany
| | - Shengfa Ye
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
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27
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Chang H, Lin Y, Werlé C, Neese F, Lee W, Bill E, Ye S. Conversion of a Fleeting Open‐Shell Iron Nitride into an Iron Nitrosyl. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201908689] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Hao‐Ching Chang
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
| | - Yen‐Hao Lin
- Department of ChemistryNational Taiwan Normal University 88, Ting-chou Rd. Sec. 4 11677 Taipei Taiwan
| | - Christophe Werlé
- Max-Planck-Institut für Chemische Energiekonversion Stiftstrasse 34–36 45470 Mülheim an der Ruhr Germany
| | - Frank Neese
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
| | - Way‐Zen Lee
- Department of ChemistryNational Taiwan Normal University 88, Ting-chou Rd. Sec. 4 11677 Taipei Taiwan
- Department of Medicinal and Applied ChemistryKaohsiung Medical University 100, Shi-Chuan 1st Rd. 807 Kaohsiung Taiwan
| | - Eckhard Bill
- Max-Planck-Institut für Chemische Energiekonversion Stiftstrasse 34–36 45470 Mülheim an der Ruhr Germany
| | - Shengfa Ye
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
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28
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Ghannam J, Sun Z, Cundari TR, Zeller M, Lugosan A, Stanek CM, Lee WT. Intramolecular C-H Functionalization Followed by a [2 σ + 2 π] Addition via an Intermediate Nickel-Nitridyl Complex. Inorg Chem 2019; 58:7131-7135. [PMID: 31117623 DOI: 10.1021/acs.inorgchem.9b00168] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Irradiation of a disphenoidal Ni(II) azido complex, [Cz tBu(Pyr iPr)2NiN3] (1), revealed an unprecedented nickel complex, [Cz tBu(Pyr iPr)(NH2-Pyr iPr)] (2), in >90% isolated yield. As evidenced by single-crystal X-ray diffraction, 2 is produced by double intramolecular C-H activation of a putative nickel-nitridyl intermediate, [Cz tBu(Pyr iPr)2Ni-⃛N•]. Calculations support the generation of an intermediate with significant nitridyl radical character after the loss of N2, which, in turn, undergoes tandem C-H activations, leading to functionalized intermediates and products. This is an unprecedented example of transient Ni-⃛N•-promoted intramolecular C-H functionalization, followed by a [2σ + 2π] addition, yielding bis-metallacyclic product 2. Complex 2 is also observed from the reaction of Ni(I) precursor Cz tBu(Pyr iPr)2Ni (3) and Me3SiN3, suggesting a unique thermal route toward a masked nickel-nitridyl intermediate.
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Affiliation(s)
- Jack Ghannam
- Department of Chemistry and Biochemistry , Loyola University Chicago , Chicago , Illinois 60660 , United States
| | - Zhicheng Sun
- Department of Chemistry, Center for Advanced Scientific Computing and Modeling (CASCaM) , University of North Texas , Denton , Texas 76203 , United States
| | - Thomas R Cundari
- Department of Chemistry, Center for Advanced Scientific Computing and Modeling (CASCaM) , University of North Texas , Denton , Texas 76203 , United States
| | - Matthias Zeller
- Department of Chemistry , Purdue University , West Lafayette , Indiana 47907 , United States
| | - Adriana Lugosan
- Department of Chemistry and Biochemistry , Loyola University Chicago , Chicago , Illinois 60660 , United States
| | - Christopher M Stanek
- Department of Chemistry and Biochemistry , Loyola University Chicago , Chicago , Illinois 60660 , United States
| | - Wei-Tsung Lee
- Department of Chemistry and Biochemistry , Loyola University Chicago , Chicago , Illinois 60660 , United States
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29
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Shylin SI, Pavliuk MV, D'Amario L, Mamedov F, Sá J, Berggren G, Fritsky IO. Efficient visible light-driven water oxidation catalysed by an iron(iv) clathrochelate complex. Chem Commun (Camb) 2019; 55:3335-3338. [PMID: 30801592 DOI: 10.1039/c9cc00229d] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A water-stable FeIV clathrochelate complex catalyses fast and homogeneous photochemical oxidation of water to dioxygen with a turnover frequency of 2.27 s-1 and a maximum turnover number of 365. An FeV intermediate generated under catalytic conditions is trapped and characterised using EPR and Mössbauer spectroscopy.
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Affiliation(s)
- Sergii I Shylin
- Department of Chemistry -Ångström Laboratory, Uppsala University, PO Box 523, 75120 Uppsala, Sweden.
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30
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Chang HC, Mondal B, Fang H, Neese F, Bill E, Ye S. Electron Paramagnetic Resonance Signature of Tetragonal Low Spin Iron(V)-Nitrido and -Oxo Complexes Derived from the Electronic Structure Analysis of Heme and Non-Heme Archetypes. J Am Chem Soc 2019; 141:2421-2434. [PMID: 30620571 PMCID: PMC6728100 DOI: 10.1021/jacs.8b11429] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Iron(V)-nitrido and -oxo complexes
have been proposed as key intermediates
in a diverse array of chemical transformations. Herein we present
a detailed electronic-structure analysis of [FeV(N)(TPP)]
(1, TPP2– = tetraphenylporphyrinato),
and [FeV(N)(cyclam-ac)]+ (2, cyclam-ac
= 1,4,8,11-tetraazacyclotetradecane-1-acetato) using electron paramagnetic
resonance (EPR) and 57Fe Mössbauer spectroscopy
coupled with wave function based complete active-space self-consistent
field (CASSCF) calculations. The findings were compared with all other
well-characterized genuine iron(V)-nitrido and -oxo complexes, [FeV(N)(MePy2tacn)](PF6)2 (3, MePy2tacn = methyl-N′,N″-bis(2-picolyl)-1,4,7-triazacyclononane), [FeV(N){PhB(t-BuIm)3}]+ (4, PhB(tBuIm)3– = phenyltris(3-tert-butylimidazol-2-ylidene)borate),
and [FeV(O)(TAML)]− (5,
TAML4– = tetraamido macrocyclic ligand). Our results
revealed that complex 1 is an authenticated iron(V)-nitrido
species and contrasts with its oxo congener, compound I, which contains
a ferryl unit interacting with a porphyrin radical. More importantly,
tetragonal iron(V)-nitrido and -oxo complexes 1–3 and 5 all possess an orbitally nearly doubly
degenerate S = 1/2 ground state. Consequently, analogous
near-axial EPR spectra with g|| < g⊥ ≤ 2 were measured for them,
and their g|| and g⊥ values were found to obey a simple relation of g⊥2 + (2 – g∥)2 = 4. However, the bonding situation for trigonal iron(V)-nitrido
complex 4 is completely different as evidenced by its
distinct EPR spectrum with g|| < 2
< g⊥. Further in-depth analyses
suggested that tetragonal low spin iron(V)-nitrido and -oxo complexes
feature electronic structures akin to those found for complexes 1–3 and 5. Therefore, the
characteristic EPR signals determined for 1–3 and 5 can be used as a spectroscopic marker
to identify such highly reactive intermediates in catalytic processes.
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Affiliation(s)
- Hao-Ching Chang
- Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelm-Platz 1 , D-45470 Mülheim an der Ruhr , Germany
| | - Bhaskar Mondal
- Max-Planck-Institut für Chemische Energiekonversion , Stiftstr. 34-36 , D-45470 Mülheim an der Ruhr , Germany
| | - Huayi Fang
- Max-Planck-Institut für Chemische Energiekonversion , Stiftstr. 34-36 , D-45470 Mülheim an der Ruhr , Germany
| | - Frank Neese
- Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelm-Platz 1 , D-45470 Mülheim an der Ruhr , Germany
| | - Eckhard Bill
- Max-Planck-Institut für Chemische Energiekonversion , Stiftstr. 34-36 , D-45470 Mülheim an der Ruhr , Germany
| | - Shengfa Ye
- Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelm-Platz 1 , D-45470 Mülheim an der Ruhr , Germany
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31
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Wong GF, Yeung LF, Tsoi HY, Chan H, Chiang M, Lee HK. A Mononuclear Iron(II) Bis(guanidinate) Complex: Synthesis, Structure, and Reactivity. Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201800815] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- George Fai Wong
- Department of Chemistry The Chinese University of Hong Kong Shatin New Territories Hong Kong
| | - Lai Fong Yeung
- Department of Chemistry The Chinese University of Hong Kong Shatin New Territories Hong Kong
| | - Ho Yin Tsoi
- Department of Chemistry The Chinese University of Hong Kong Shatin New Territories Hong Kong
| | - Hoi‐Shan Chan
- Department of Chemistry The Chinese University of Hong Kong Shatin New Territories Hong Kong
| | - Ming‐Hsi Chiang
- Institute of Chemistry Academia Sinica 128 Academia Road Sec. 2, Nankang 115 Taipei Taiwan
| | - Hung Kay Lee
- Department of Chemistry The Chinese University of Hong Kong Shatin New Territories Hong Kong
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32
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Buss JA, Cheng C, Agapie T. A Low‐Valent Molybdenum Nitride Complex: Reduction Promotes Carbonylation Chemistry. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201803728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Joshua A. Buss
- Division of Chemistry and Chemical Engineering California Institute of Technology Pasadena CA 91125 USA
| | - Christine Cheng
- Division of Chemistry and Chemical Engineering California Institute of Technology Pasadena CA 91125 USA
| | - Theodor Agapie
- Division of Chemistry and Chemical Engineering California Institute of Technology Pasadena CA 91125 USA
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33
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Heins SP, Morris WD, Cundari TR, MacMillan SN, Lobkovsky EB, Livezey NM, Wolczanski PT. Complexes of [(dadi)Ti(L/X)]m That Reveal Redox Non-Innocence and a Stepwise Carbene Insertion into a Carbon–Carbon Bond. Organometallics 2018. [DOI: 10.1021/acs.organomet.8b00188] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Spencer P. Heins
- Department of Chemistry & Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Wesley D. Morris
- Department of Chemistry & Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Thomas R. Cundari
- Department of Chemistry, CASCaM, University of North Texas, Denton, Texas 76201, United States
| | - Samantha N. MacMillan
- Department of Chemistry & Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Emil B. Lobkovsky
- Department of Chemistry & Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Nicholas M. Livezey
- Department of Chemistry & Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Peter T. Wolczanski
- Department of Chemistry & Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
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34
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Buss JA, Cheng C, Agapie T. A Low‐Valent Molybdenum Nitride Complex: Reduction Promotes Carbonylation Chemistry. Angew Chem Int Ed Engl 2018; 57:9670-9674. [DOI: 10.1002/anie.201803728] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 05/31/2018] [Indexed: 11/07/2022]
Affiliation(s)
- Joshua A. Buss
- Division of Chemistry and Chemical Engineering California Institute of Technology Pasadena CA 91125 USA
| | - Christine Cheng
- Division of Chemistry and Chemical Engineering California Institute of Technology Pasadena CA 91125 USA
| | - Theodor Agapie
- Division of Chemistry and Chemical Engineering California Institute of Technology Pasadena CA 91125 USA
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35
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Schwamm RJ, Lein M, Coles MP, Fitchett CM. Bismuth(III) Complex of the [S4]•– Radical Anion: Dimer Formation via Pancake Bonds. J Am Chem Soc 2017; 139:16490-16493. [DOI: 10.1021/jacs.7b10454] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Ryan J. Schwamm
- School
of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, New Zealand
| | - Matthias Lein
- School
of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, New Zealand
| | - Martyn P. Coles
- School
of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, New Zealand
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