1
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Török P, Lakk-Bogáth D, Unjaroen D, Browne WR, Kaizer J. Effect of monodentate heterocycle co-ligands on the μ-1,2-peroxo-diiron(III) mediated aldehyde deformylation reactions. J Inorg Biochem 2024; 258:112620. [PMID: 38824901 DOI: 10.1016/j.jinorgbio.2024.112620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 05/17/2024] [Accepted: 05/25/2024] [Indexed: 06/04/2024]
Abstract
Peroxo-diiron(III) species are present in the active sites of many metalloenzymes that carry out challenging organic transformations. The reactivity of these species is influenced by various factors, such as the structure and topology of the supporting ligands, the identity of the axial and equatorial co-ligands, and the oxidation states of the metal ion(s). In this study, we aim to diversify the importance of equatorial ligands in controlling the reactivity of peroxo-diiron(III) species. As a model compound, we chose the previously published and fully characterized [(PBI)2(CH3CN)FeIII(μ-O2)FeIII(CH3CN)(PBI)2]4+ complex, where the steric effect of the four PBI ligands is minimal, so the labile CH3CN molecules easily can be replaced by different monodentate co-ligands (substituted pyridines and N-donor heterocyclic compounds). Thus, their effect on the electronic and spectral properties of peroxo-divas(III) intermediates could be easily investigated. The relationship between structure and reactivity was also investigated in the stoichiometric deformylation of PPA mediated by peroxo-diiron(III) complexes. It was found that the deformylation rates are influenced by the Lewis acidity and redox properties of the metal centers, and showed a linear correlation with the FeIII/FeII redox potentials (in the range of 197 to 415 mV).
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Affiliation(s)
- Patrik Török
- Research Group of Bioorganic and Biocoordination Chemistry, Universtiy of Pannonia, 8201 Veszprém, Hungary
| | - Dóra Lakk-Bogáth
- Research Group of Bioorganic and Biocoordination Chemistry, Universtiy of Pannonia, 8201 Veszprém, Hungary
| | - Duenpen Unjaroen
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands
| | - Wesley R Browne
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands.
| | - József Kaizer
- Research Group of Bioorganic and Biocoordination Chemistry, Universtiy of Pannonia, 8201 Veszprém, Hungary.
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2
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Rice DB, Wong D, Weyhermüller T, Neese F, DeBeer S. The spin-forbidden transition in iron(IV)-oxo catalysts relevant to two-state reactivity. SCIENCE ADVANCES 2024; 10:eado1603. [PMID: 38941457 PMCID: PMC11212722 DOI: 10.1126/sciadv.ado1603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 05/23/2024] [Indexed: 06/30/2024]
Abstract
Quintet oxoiron(IV) intermediates are often invoked in nonheme iron enzymes capable of performing selective oxidation, while most well-characterized synthetic model oxoiron(IV) complexes have a triplet ground state. These differing spin states lead to the proposal of a two-state reactivity model, where the complexes cross from the triplet to an excited quintet state. However, the energy of this quintet state has never been measured experimentally. Here, magnetic circular dichroism is used to assign the singlet and triplet excited states in a series of triplet oxoiron(IV) complexes. These transition energies are used to determine the energies of the quintet state via constrained fitting of 2p3d resonant inelastic x-ray scattering. This allowed for a direct correlation between the quintet energies and substrate C─H oxidation rates.
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Affiliation(s)
- Derek B. Rice
- Max Planck Institute for Chemical Energy Conversion, D-45470 Mülheim an der Ruhr, Germany
| | - Deniz Wong
- Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany
| | - Thomas Weyhermüller
- Max Planck Institute for Chemical Energy Conversion, D-45470 Mülheim an der Ruhr, Germany
| | - Frank Neese
- Max-Planck-Institut für Kohlenforschung, D-45470 Mülheim an der Ruhr, Germany
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion, D-45470 Mülheim an der Ruhr, Germany
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3
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Kubo M, Nakane D, Funahashi Y, Ozawa T, Inomata T, Masuda H. Catalytic Oxidation of Methanol to Formaldehyde Catalyzed by Iron Complex with N 3S 3-type Tripodal Ligand. Chemistry 2024; 30:e202303955. [PMID: 38268122 DOI: 10.1002/chem.202303955] [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: 11/28/2023] [Revised: 01/19/2024] [Accepted: 01/24/2024] [Indexed: 01/26/2024]
Abstract
A Fe3+ complex with N3S3-type tripod ligand, 1, reacts with O2 in CH3OH to generate formaldehyde, which has been studied structurally, spectroscopically, and electrochemically. Complex 1 crystallizes as an octahedral structure with crystallographic C3 symmetry around the metal, with Fe-N=2.2917(17) Å and Fe-S=2.3574(6) Å. UV-vis spectrum of 1 in CH3OH under Ar shows an intense band at 572 nm (ϵ 4,100 M-1cm-1), which shifts to 590 nm (ϵ 2,860 M-1cm-1) by the addition of O2, and a new peak appeared at 781 nm (ϵ 790 M-1cm-1). Such a spectral change is not observed in CH2Cl2. Cyclic voltammogram (CV) of 1 in CH2Cl2 under Ar gives reversible redox waves assigned to Fe2+/Fe3+ and Fe3+/Fe4+ couples at -1.60 V (ΔE=69 mV) and -0.53 V (ΔE=71 mV) vs Fc/Fc+, respectively. In contrast, in CH3OH, the reversible redox waves, albeit accompanied by a positive shift of the Fe2+/Fe3+ couple, are observed at -1.20 V (ΔE=85 mV) and -0.53 V (ΔE=64 mV) vs Fc/Fc+ under Ar. Interestingly, a catalytic current was observed for the CV of 1 in CH3OH in the presence of CH3ONa under Ar, when the sweep rate was slowed down.
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Affiliation(s)
- Masaki Kubo
- Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa, Nagoya, 466-8555, Japan
| | - Daisuke Nakane
- Department of Chemistry, Faculty of Science Division II, Tokyo University of Science, 1-3 Kagurazaka Shinjuku, Tokyo, 162-0825, Japan
| | - Yasuhiro Funahashi
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan
| | - Tomohiro Ozawa
- Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa, Nagoya, 466-8555, Japan
| | - Tomohiko Inomata
- Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa, Nagoya, 466-8555, Japan
| | - Hideki Masuda
- Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa, Nagoya, 466-8555, Japan
- Department of Applied Chemistry, Aichi Institute of Technology, 1247 Yachigusa, Yakusa-cho, Toyota, 470-0392, Japan
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4
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Kumar R, Ansari A, Comba P, Rajaraman G. Rebound or Cage Escape? The Role of the Rebound Barrier for the Reactivity of Non-Heme High-Valent Fe IV =O Species. Chemistry 2024; 30:e202303300. [PMID: 37929771 DOI: 10.1002/chem.202303300] [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: 10/09/2023] [Revised: 11/03/2023] [Accepted: 11/06/2023] [Indexed: 11/07/2023]
Abstract
Owing to their high reactivity and selectivity, variations in the spin ground state and a range of possible pathways, high-valent FeIV =O species are popular models with potential bioinspired applications. An interesting example of a structure-reactivity pattern is the detailed study with five nonheme amine-pyridine pentadentate ligand FeIV =O species, including N4py: [(L1 )FeIV =O]2+ (1), bntpen: [(L2 )FeIV =O]2+ (2), py2 tacn: [(L3 )FeIV =O]2+ (3), and two isomeric bispidine derivatives: [(L4 )FeIV =O]2+ (4) and [(L5 )FeIV =O]2+ (5). In this set, the order of increasing reactivity in the hydroxylation of cyclohexane differs from that with cyclohexadiene as substrate. A comprehensive DFT, ab initio CASSCF/NEVPT2 and DLPNO-CCSD(T) study is presented to untangle the observed patterns. These are well reproduced when both activation barriers for the C-H abstraction and the OH rebound are taken into account. An MO, NBO and deformation energy analysis reveals the importance of π(pyr) → π*xz (FeIII -OH) electron donation for weakening the FeIII -OH bond and thus reducing the rebound barrier. This requires that pyridine rings are oriented perpendicularly to the FeIII -OH bond and this is a subtle but crucial point in ligand design for non-heme iron alkane hydroxylation.
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Affiliation(s)
- Ravi Kumar
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, Powai, 400076, India
| | - Azaj Ansari
- Department of Chemistry, Central University of Haryana, Haryana, 123031, India
| | - Peter Comba
- Institute of Inorganic Chemistry &, Interdisciplinary Center for Scientific Computing, Heidelberg University, 69120, Heidelberg, Germany
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, Powai, 400076, India
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5
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Mahajan M, Mondal B. How Axial Coordination Regulates the Electronic Structure and C-H Amination Reactivity of Fe-Porphyrin-Nitrene? JACS AU 2023; 3:3494-3505. [PMID: 38155653 PMCID: PMC10751768 DOI: 10.1021/jacsau.3c00670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 11/22/2023] [Accepted: 11/27/2023] [Indexed: 12/30/2023]
Abstract
Detailed electronic structure and its correlation with the intramolecular C-H amination reactivity of Fe-porphyrin-nitrene intermediates bearing different "axial" coordination have been investigated using multiconfigurational complete active space self-consistent field (CASSCF), N-electron valence perturbation theory (NEVPT2), and hybrid density functional theory (DFT-B3LYP) calculations. Three types of "axial" coordination, -OMe/-O(H)Me (1-Sul/2-Sul), -SMe/-S(H)Me (3-Sul/4-Sul), and -NMeIm (MeIm = 3-methyl-imidazole) (5-Sul) mimicking serine, cysteine, and histidine, respectively, along with no axial coordination (6-Sul) have been considered to decipher how the "axial" coordination of different strengths regulates the electronic integrity of the Fe-N core and nitrene-transfer reactivity of Fe-porphyrin-nitrene intermediates. CASSCF-based natural orbitals reveal two distinct classes of electronic structures: Fe-nitrenes (1-Sul and 3-Sul) with relatively stronger axial coordination (-OMe and -SMe) display "imidyl" nature and those (2-Sul, 4-Sul, and 6-Sul) with weaker axial coordination (-O(H)Me, -S(H)Me and no axial coordination) exhibit "imido-like" character. A borderline between the two classes is also observed with NMeIm axial coordination (5-Sul). Axial coordination of different strengths not only regulates the electronic structure but also modulates the Fe-3d orbital energies, as revealed through the d-d transition energies obtained by CASSCF/NEVPT2 calculations. The relatively lower energy of Fe-3dz2 orbital allows easy access to low-lying high-spin quintet states in the cases of weaker "axial" coordination (2-Sul, 4-Sul, and 6-Sul), and the associated hydrogen atom transfer (HAT) reactivity appears to involve two-state triplet-quintet reactivity through minimum energy crossing point (3,5MECP) between the spin states. In stark contrast, Fe-nitrenes with relatively stronger "axial" coordination (1-Sul and 3-Sul) undergo triplet-only HAT reactivity. Overall, this in-depth electronic structure investigation and HAT reactivity evaluation reveal that the weaker axial coordination in Fe-porphyrin-nitrene complexes (2-Sul, 4-Sul, and 6-Sul) can promote more efficient C-H oxidation through the quintet spin state.
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Affiliation(s)
- Mayank Mahajan
- School of Chemical Sciences, Indian Institute of Technology Mandi, Mandi, Himachal Pradesh 175075, India
| | - Bhaskar Mondal
- School of Chemical Sciences, Indian Institute of Technology Mandi, Mandi, Himachal Pradesh 175075, India
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6
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Lakk-Bogáth D, Pintarics D, Török P, Kaizer J. Influence of Equatorial Co-Ligands on the Reactivity of LFe IIIOIPh. Molecules 2023; 29:58. [PMID: 38202641 PMCID: PMC10779584 DOI: 10.3390/molecules29010058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 12/18/2023] [Accepted: 12/19/2023] [Indexed: 01/12/2024] Open
Abstract
Previous biomimetic studies clearly proved that equatorial ligands significantly influence the redox potential and thus the stability/reactivity of biologically important oxoiron intermediates; however, no such studies were performed on FeIIIOIPh species. In this study, the influence of substituted pyridine co-ligands on the reactivity of iron(III)-iodosylbenzene adduct has been investigated in sulfoxidation and epoxidation reactions. Selective oxidation of thioanisole, cis-cyclooctene, and cis- and trans-stilbene in the presence of a catalytic amount of [FeII(PBI)3](OTf)2 with PhI(OAc)2 provide products in good to excellent yields through an FeIIIOIPh intermediate depending on the co-ligand (4R-Py) used. Several mechanistic studies were performed to gain more insight into the mechanism of oxygen atom transfer (OAT) reactions to support the reactive intermediate and investigate the effect of the equatorial co-ligands. Based on competitive experiments, including a linear free-energy relationship between the relative reaction rates (logkrel) and the σp (4R-Py) parameters, strong evidence has been observed for the electrophilic character of the reactive species. The presence of the [(PBI)2(4R-Py)FeIIIOIPh]3+ intermediates and the effect of the co-ligands was also supported by UV-visible measurements, including the color change from red to green and the hypsochromic shifts in the presence of co-ligands. This is another indication that the title iron(III)-iodosylbenzene adduct is able to oxygenate sulfides and alkenes before it is transformed into the oxoiron form by cleavage of the O-I bond.
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Affiliation(s)
| | | | | | - József Kaizer
- Research Group of Bioorganic and Biocoordination Chemistry, University of Pannonia, H-8201 Veszprém, Hungary; (D.L.-B.); (D.P.); (P.T.)
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7
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Li Y, Singh R, Sinha A, Lisensky GC, Haukka M, Nilsson J, Yiga S, Demeshko S, Gross SJ, Dechert S, Gonzalez A, Farias G, Wendt OF, Meyer F, Nordlander E. Nonheme Fe IV═O Complexes Supported by Four Pentadentate Ligands: Reactivity toward H- and O- Atom Transfer Processes. Inorg Chem 2023; 62:18338-18356. [PMID: 37913548 PMCID: PMC10647104 DOI: 10.1021/acs.inorgchem.3c02526] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 10/06/2023] [Accepted: 10/11/2023] [Indexed: 11/03/2023]
Abstract
Four new pentadentate N5-donor ligands, [N-(1-methyl-2-imidazolyl)methyl-N-(2-pyridyl)-methyl-N-(bis-2-pyridylmethyl)-amine] (L1), [N-bis(1-methyl-2-imidazolyl)methyl-N-(bis-2-pyridylmethyl)amine] (L2), (N-(isoquinolin-3-ylmethyl)-1,1-di(pyridin-2-yl)-N-(pyridin-2-ylmethyl)methanamine (L3), and N,N-bis(isoquinolin-3-ylmethyl)-1,1-di(pyridin-2-yl)methanamine (L4), have been synthesized based on the N4Py ligand framework, where one or two pyridyl arms of the N4Py parent are replaced by (N-methyl)imidazolyl or N-(isoquinolin-3-ylmethyl) moieties. Using these four pentadentate ligands, the mononuclear complexes [FeII(CH3CN)(L1)]2+ (1a), [FeII(CH3CN)(L2)]2+ (2a), [FeII(CH3CN)(L3)]2+ (3a), and [FeII(CH3CN)(L4)]2+ (4a) have been synthesized and characterized. The half-wave potentials (E1/2) of the complexes become more positive in the order: 2a < 1a < 4a ≤ 3a ≤ [Fe(N4Py)(CH3CN)]2+. The order of redox potentials correlates well with the Fe-Namine distances observed by crystallography, which are 2a > 1a ≥ 4a > 3a ≥ [Fe(N4Py)(CH3CN)]2+. The corresponding ferryl complexes [FeIV(O)(L1)]2+ (1b), [FeIV(O)(L2)]2+ (2b), [FeIV(O)(L3)]2+ (3b), and [FeIV(O)(L4)]2+ (4b) were prepared by the reaction of the ferrous complexes with isopropyl 2-iodoxybenzoate (IBX ester) in acetonitrile. The greenish complexes 3b and 4b were also isolated in the solid state by the reaction of the ferrous complexes in CH3CN with ceric ammonium nitrate in water. Mössbauer spectroscopy and magnetic measurements (using superconducting quantum interference device) show that the four complexes 1b, 2b, 3b, and 4b are low-spin (S = 1) FeIV═O complexes. UV/vis spectra of the four FeIV═O complexes in acetonitrile show typical long-wavelength absorptions of around 700 nm, which are expected for FeIV═O complexes with N4Py-type ligands. The wavelengths of these absorptions decrease in the following order: 721 nm (2b) > 706 nm (1b) > 696 nm (4b) > 695 nm (3b) = 695 nm ([FeIV(O) (N4Py)]2+), indicating that the replacement of the pyridyl arms with (N-methyl) imidazolyl moieties makes L1 and L2 exert weaker ligand fields than the parent N4Py ligand, while the ligand field strengths of L3 and L4 are similar to the N4Py parent despite the replacement of the pyridyl arms with N-(isoquinolin-3-ylmethyl) moieties. Consequently, complexes 1b and 2b tend to be less stable than the parent [FeIV(O)(N4Py)]2+ complex: the half-life sequence at room temperature is 1.67 h (2b) < 16 h (1b) < 45 h (4b) < 63 h (3b) ≈ 60 h ([FeIV(O)(N4Py)]2+). Compared to the parent complex, 1b and 2b exhibit enhanced reactivity in both the oxidation of thioanisole in the oxygen atom transfer (OAT) reaction and the oxygenation of C-H bonds of aromatic and aliphatic substrates, presumed to occur via an oxygen rebound process. Furthermore, the second-order rate constants for hydrogen atom transfer (HAT) reactions affected by the ferryl complexes can be directly related to the C-H bond dissociation energies of a range of substrates that have been studied. Using either IBX ester or H2O2 as an oxidant, all four new FeII complexes display good performance in catalytic reactions involving both HAT and OAT reactions.
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Affiliation(s)
- Yong Li
- Chemical
Physics, Department of Chemistry, Lund University, Box 124, Lund SE-221 00, Sweden
| | - Reena Singh
- Chemical
Physics, Department of Chemistry, Lund University, Box 124, Lund SE-221 00, Sweden
| | - Arup Sinha
- Chemical
Physics, Department of Chemistry, Lund University, Box 124, Lund SE-221 00, Sweden
| | - George C. Lisensky
- Department
of Chemistry, Beloit College, 700 College Street, Beloit, Wisconsin 53511, United States
| | - Matti Haukka
- Department
of Chemistry, University of Jyväskylä, P.O. Box-35, Jyväskylä FI-40014, Finland
| | - Justin Nilsson
- Chemical
Physics, Department of Chemistry, Lund University, Box 124, Lund SE-221 00, Sweden
| | - Solomon Yiga
- Centre
for Analysis and Synthesis, Department of Chemistry, Lund University, P.O. Box 124, Lund SE-22100, Sweden
| | - Serhiy Demeshko
- Georg-August
Universität Göttingen, Institut
für Anorganische Chemie, Tammanstrasse 4, Göttingen D-37077, Germany
| | - Sophie Jana Gross
- Georg-August
Universität Göttingen, Institut
für Anorganische Chemie, Tammanstrasse 4, Göttingen D-37077, Germany
| | - Sebastian Dechert
- Georg-August
Universität Göttingen, Institut
für Anorganische Chemie, Tammanstrasse 4, Göttingen D-37077, Germany
| | - Ana Gonzalez
- MAX IV Laboratory, Lund University, P.O.
Box 118, Lund SE-221 00, Sweden
| | - Giliandro Farias
- Department
of Chemistry, Federal University of Santa
Catarina, Florianópolis 88040900, Santa Catarina, Brazil
| | - Ola F. Wendt
- Centre
for Analysis and Synthesis, Department of Chemistry, Lund University, P.O. Box 124, Lund SE-22100, Sweden
| | - Franc Meyer
- Georg-August
Universität Göttingen, Institut
für Anorganische Chemie, Tammanstrasse 4, Göttingen D-37077, Germany
| | - Ebbe Nordlander
- Chemical
Physics, Department of Chemistry, Lund University, Box 124, Lund SE-221 00, Sweden
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Ghosh S, Bhardwaj A, Mondal B. Revisiting the electronic structure of N 2-bound cAAC-borylene at the CASSCF level: a detailed bonding picture of borylene-N 2 interaction. Dalton Trans 2023; 52:12517-12525. [PMID: 37606083 DOI: 10.1039/d3dt01155k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
A base-trapped borylene species featuring a cyclic-(alkyl)(amino)carbene (cAAC) has shown unique bonding interactions with dinitrogen, thereby, opening a new avenue for N2 activation by main-group compounds. The detailed electronic structure and qualitative bonding picture between cAAC-trapped borylene and N2 remain to be fully understood. This work presents a multiconfigurational complete active space self-consistent field (CASSCF)-based electronic structure investigation on the N2-bound cAAC-borylene species (1) isolated by Braunschweig et al. Specifically, the synergistic bonding between the borylene units and N2 involving the donation from the N-N σ to the unoccupied orbital of borylene and back-donation from the occupied orbital of borylene to the N-N π* has been unequivocally established using CASSCF-derived natural orbitals and electronic configuration. Bonding interactions between the HOMO of the borylene units and the N-N π* (HOMOcAAC-B + π*NN) and the LUMO of the borylene units and the N-N σ (LUMOcAAC-B + σNN) in 1 were apparent through the CASSCF-derived natural orbitals. The unique bonding of the B-N-N-B core in 1 and the resulting geometry have also been compared with the M-N-N-M core of a prototypical transition metal(M)-N2 complex. Finally, the change in the electronic structure and geometry of the N2-bound borylene species 1 on two-electron reduction has been investigated in the context of N2 activation.
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Affiliation(s)
- Susovon Ghosh
- School of Chemical Sciences, Indian Institute of Technology Mandi, Mandi, Himachal Pradesh 175005, India.
| | - Akhil Bhardwaj
- School of Chemical Sciences, Indian Institute of Technology Mandi, Mandi, Himachal Pradesh 175005, India.
| | - Bhaskar Mondal
- School of Chemical Sciences, Indian Institute of Technology Mandi, Mandi, Himachal Pradesh 175005, India.
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9
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Liu Y, Chatterjee S, Cutsail GE, Peredkov S, Gupta SK, Dechert S, DeBeer S, Meyer F. Cu 4S Cluster in "0-Hole" and "1-Hole" States: Geometric and Electronic Structure Variations for the Active Cu Z* Site of N 2O Reductase. J Am Chem Soc 2023; 145:18477-18486. [PMID: 37565682 PMCID: PMC10450684 DOI: 10.1021/jacs.3c04893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Indexed: 08/12/2023]
Abstract
The active site of nitrous oxide reductase (N2OR), a key enzyme in denitrification, features a unique μ4-sulfido-bridged tetranuclear Cu cluster (the so-called CuZ or CuZ* site). Details of the catalytic mechanism have remained under debate and, to date, synthetic model complexes of the CuZ*/CuZ sites are extremely rare due to the difficulty in building the unique {Cu4(μ4-S)} core structure. Herein, we report the synthesis and characterization of [Cu4(μ4-S)]n+ (n = 2, 2; n = 3, 3) clusters, supported by a macrocyclic {py2NHC4} ligand (py = pyridine, NHC = N-heterocyclic carbene), in both their 0-hole (2) and 1-hole (3) states, thus mimicking the two active states of the CuZ* site during enzymatic N2O reduction. Structural and electronic properties of these {Cu4(μ4-S)} clusters are elucidated by employing multiple methods, including X-ray diffraction (XRD), nuclear magnetic resonance (NMR), UV/vis, electron paramagnetic resonance (EPR), Cu/S K-edge X-ray emission spectroscopy (XES), and Cu K-edge X-ray absorption spectroscopy (XAS) in combination with time-dependent density functional theory (TD-DFT) calculations. A significant geometry change of the {Cu4(μ4-S)} core occurs upon oxidation from 2 (τ4(S) = 0.46, seesaw) to 3 (τ4(S) = 0.03, square planar), which has not been observed so far for the biological CuZ(*) site and is unprecedented for known model complexes. The single electron of the 1-hole species 3 is predominantly delocalized over two opposite Cu ions via the central S atom, mediated by a π/π superexchange pathway. Cu K-edge XAS and Cu/S K-edge XES corroborate a mixed Cu/S-based oxidation event in which the lowest unoccupied molecular orbital (LUMO) has a significant S-character. Furthermore, preliminary reactivity studies evidence a nucleophilic character of the central μ4-S in the fully reduced 0-hole state.
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Affiliation(s)
- Yang Liu
- Institute
of Inorganic Chemistry, University of Göttingen, Tammannstraße 4, 37077 Göttingen, Germany
| | - Sayanti Chatterjee
- Max
Planck Institute for Chemical Energy Conversion, Stiftstrasse 34−36, 45470 Mülheim an der Ruhr, Germany
| | - George E. Cutsail
- Max
Planck Institute for Chemical Energy Conversion, Stiftstrasse 34−36, 45470 Mülheim an der Ruhr, Germany
- Institute
of Inorganic Chemistry, University of Duisburg-Essen, Universitätsstraße 7, 45117 Essen, Germany
| | - Sergey Peredkov
- Max
Planck Institute for Chemical Energy Conversion, Stiftstrasse 34−36, 45470 Mülheim an der Ruhr, Germany
| | - Sandeep K. Gupta
- Institute
of Inorganic Chemistry, University of Göttingen, Tammannstraße 4, 37077 Göttingen, Germany
| | - Sebastian Dechert
- Institute
of Inorganic Chemistry, University of Göttingen, Tammannstraße 4, 37077 Göttingen, Germany
| | - Serena DeBeer
- Max
Planck Institute for Chemical Energy Conversion, Stiftstrasse 34−36, 45470 Mülheim an der Ruhr, Germany
| | - Franc Meyer
- Institute
of Inorganic Chemistry, University of Göttingen, Tammannstraße 4, 37077 Göttingen, Germany
- International
Center for Advanced Studies of Energy Conversion (ICASEC), University of Göttingen, Tammannstraße 6, 37077 Göttingen, Germany
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10
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Follmer AH, Borovik AS. The role of basicity in selective C-H bond activation by transition metal-oxidos. Dalton Trans 2023; 52:11005-11016. [PMID: 37497779 PMCID: PMC10619463 DOI: 10.1039/d3dt01781h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/28/2023]
Abstract
The development of (bio)catalysts capable of selectively activating strong C-H bonds is a continuing challenge in modern chemistry. In both metalloenzymes and synthetic systems capable of activating C-H bonds, transition metal-oxido intermediates serve as the active species for reactivity whose thermodynamic properties influence the bond strengths they are capable of activating. In this Frontier article, we present current ideas of how the basicity of transition metal-oxidos impacts their reactivity with C-H bonds and present new opportunities within this field. We highlight recent insights into the role basicity plays in the activation process and its influence on mechanism, as well as the important role that secondary coordination sphere effects, such as hydrogen bonds, in tuning the basicity of the metal-oxido species is discussed.
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Affiliation(s)
- Alec H Follmer
- Department of Chemistry, University of California-Irvine, Irvine, CA 92697-3900, USA.
| | - A S Borovik
- Department of Chemistry, University of California-Irvine, Irvine, CA 92697-3900, USA.
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11
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Bleher K, Comba P, Kass D, Ray K, Wadepohl H. Reactivities of iron(IV)-oxido compounds with pentadentate bispidine ligands. J Inorg Biochem 2023; 241:112123. [PMID: 36701984 DOI: 10.1016/j.jinorgbio.2023.112123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 01/05/2023] [Accepted: 01/05/2023] [Indexed: 01/11/2023]
Abstract
The FeIVO complexes of bispidines (3,7-diazabicyclo[3.3.1]nonane derivatives) are known to be highly reactive oxidants - with the tetradentate bispidine, the so far most reactive ferryl complex has been reported and two isomeric pentadentate ligands also lead to very reactive high-valent oxidants. With a series of 4 new bispidine derivatives we now try to address the question why the bispidine scaffold in general leads to very reactive oxidants and how this can be tuned by ligand modifications. The study is based on a full structural, spectroscopic and electrochemical analysis of the iron(II) precursors, spectroscopic data of the iron(IV)-oxido complexes, a kinetic analysis of the stoichiometric oxidation of thioanisole by five different bispidine‑iron(IV)-oxido complexes and on product analyses of reactions by the five ferryl oxidants with thioanisole, β-methylstyrene and cis-stilbene as substrates.
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Affiliation(s)
- Katharina Bleher
- Universität Heidelberg, Anorganisch-Chemisches Institut, INF 270, D-69120 Heidelberg, Germany
| | - Peter Comba
- Universität Heidelberg, Anorganisch-Chemisches Institut, INF 270, D-69120 Heidelberg, Germany; Universität Heidelberg, Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR), Germany.
| | - Dustin Kass
- Humboldt-Universität zu Berlin, Department of Chemistry, Brook-Taylor Strasse 2, D-12489 Berlin, Germany
| | - Kallol Ray
- Humboldt-Universität zu Berlin, Department of Chemistry, Brook-Taylor Strasse 2, D-12489 Berlin, Germany
| | - Hubert Wadepohl
- Universität Heidelberg, Anorganisch-Chemisches Institut, INF 270, D-69120 Heidelberg, Germany
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12
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Schlachta TP, Kühn FE. Cyclic iron tetra N-heterocyclic carbenes: synthesis, properties, reactivity, and catalysis. Chem Soc Rev 2023; 52:2238-2277. [PMID: 36852959 DOI: 10.1039/d2cs01064j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
Cyclic iron tetracarbenes are an emerging class of macrocyclic iron N-heterocyclic carbene (NHC) complexes. They can be considered as an organometallic compound class inspired by their heme analogs, however, their electronic properties differ, e.g. due to the very strong σ-donation of the four combined NHCs in equatorial coordination. The ligand framework of iron tetracarbenes can be readily modified, allowing fine-tuning of the structural and electronic properties of the complexes. The properties of iron tetracarbene complexes are discussed quantitatively and correlations are established. The electronic nature of the tetracarbene ligand allows the isolation of uncommon iron(III) and iron(IV) species and reveals a unique reactivity. Iron tetracarbenes are successfully applied in C-H activation, CO2 reduction, aziridination and epoxidation catalysis and mechanisms as well as decomposition pathways are described. This review will help researchers evaluate the structural and electronic properties of their complexes and target their catalyst properties through ligand design.
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Affiliation(s)
- Tim P Schlachta
- Technical University of Munich, School of Natural Sciences, Department of Chemistry and Catalysis Research Center, Molecular Catalysis, Lichtenbergstraße 4, 85748 Garching, Germany.
| | - Fritz E Kühn
- Technical University of Munich, School of Natural Sciences, Department of Chemistry and Catalysis Research Center, Molecular Catalysis, Lichtenbergstraße 4, 85748 Garching, Germany.
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13
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Claveau EE, Sader S, Jackson BA, Khan SN, Miliordos E. Transition metal oxide complexes as molecular catalysts for selective methane to methanol transformation: any prospects or time to retire? Phys Chem Chem Phys 2023; 25:5313-5326. [PMID: 36723253 DOI: 10.1039/d2cp05480a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Transition metal oxides have been extensively used in the literature for the conversion of methane to methanol. Despite the progress made over the past decades, no method with satisfactory performance or economic viability has been detected. The main bottleneck is that the produced methanol oxidizes further due to its weaker C-H bond than that of methane. Every improvement in the efficiency of a catalyst to activate methane leads to reduction of the selectivity towards methanol. Is it therefore prudent to keep studying (both theoretically and experimentally) metal oxides as catalysts for the quantitative conversion of methane to methanol? This perspective focuses on molecular metal oxide complexes and suggests strategies to bypass the current bottlenecks with higher weight on the computational chemistry side. We first discuss the electronic structure of metal oxides, followed by assessing the role of the ligands in the reactivity of the catalysts. For better selectivity, we propose that metal oxide anionic complexes should be explored further, while hydrophylic cavities in the vicinity of the metal oxide can perturb the transition-state structure for methanol increasing appreciably the activation barrier for methanol. We also emphasize that computational studies should target the activation reaction of methanol (and not only methane), the study of complete catalytic cycles (including the recombination and oxidation steps), and the use of molecular oxygen as an oxidant. The titled chemical conversion is an excellent challenge for theory and we believe that computational studies should lead the field in the future. It is finally shown that bottom-up approaches offer a systematic way for exploration of the chemical space and should still be applied in parallel with the recently popular machine learning techniques. To answer the question of the title, we believe that metal oxides should still be considered provided that we change our focus and perform more systematic investigations on the activation of methanol.
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Affiliation(s)
- Emily E Claveau
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA.
| | - Safaa Sader
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA.
| | - Benjamin A Jackson
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA.
| | - Shahriar N Khan
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA.
| | - Evangelos Miliordos
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849-5312, USA.
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14
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Tian YC, Jiang Y, Lin YH, Zhang P, Wang CC, Ye S, Lee WZ. Hydrogen Atom Transfer Thermodynamics of Homologous Co(III)- and Mn(III)-Superoxo Complexes: The Effect of the Metal Spin State. JACS AU 2022; 2:1899-1909. [PMID: 36032524 PMCID: PMC9400055 DOI: 10.1021/jacsau.2c00268] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 07/22/2022] [Accepted: 07/22/2022] [Indexed: 06/15/2023]
Abstract
Systematic investigations on H atom transfer (HAT) thermodynamics of metal O2 adducts is of fundamental importance for the design of transition metal catalysts for substrate oxidation and/or oxygenation directly using O2. Such work should help elucidate underlying electronic-structure features that govern the OO-H bond dissociation free energies (BDFEs) of metal-hydroperoxo species, which can be used to quantitatively appraise the HAT activity of the corresponding metal-superoxo complexes. Herein, the BDFEs of two homologous CoIII- and MnIII-hydroperoxo complexes, 3-Co and 3-Mn, were calculated to be 79.3 and 81.5 kcal/mol, respectively, employing the Bordwell relationship based on experimentally determined pK a values and redox potentials of the one-electron-oxidized forms, 4-Co and 4-Mn. To further verify these values, we tested the HAT capability of their superoxo congeners, 2-Co and 2-Mn, toward three different substrates possessing varying O-H BDFEs. Specifically, both metal-superoxo species are capable of activating the O-H bond of 4-oxo-TEMPOH with an O-H BDFE of 68.9 kcal/mol, only 2-Mn is able to abstract a H atom from 2,4-di-tert-butylphenol with an O-H BDFE of 80.9 kcal/mol, and neither of them can react with 3,5-dimethylphenol with an O-H BDFE of 85.6 kcal/mol. Further computational investigations suggested that it is the high spin state of the MnIII center in 3-Mn that renders its OO-H BDFE higher than that of 3-Co, which features a low-spin CoIII center. The present work underscores the role of the metal spin state being as crucial as the oxidation state in modulating BDFEs.
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Affiliation(s)
- Yao-Cheng Tian
- Department
of Chemistry, National Taiwan Normal University, Taipei 11677, Taiwan
| | - Yang Jiang
- State
Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Yen-Hao Lin
- Department
of Chemistry, National Taiwan Normal University, Taipei 11677, Taiwan
| | - Peng Zhang
- 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
| | - Chun-Chieh Wang
- Department
of Chemistry, National Taiwan Normal University, Taipei 11677, Taiwan
| | - Shengfa Ye
- State
Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Way-Zen Lee
- Department
of Chemistry, National Taiwan Normal University, Taipei 11677, Taiwan
- Department
of Medicinal and Applied Chemistry, Kaohsiung
Medical University, Kaohsiung 807, Taiwan
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15
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Nandy A, Adamji H, Kastner DW, Vennelakanti V, Nazemi A, Liu M, Kulik HJ. Using Computational Chemistry To Reveal Nature’s Blueprints for Single-Site Catalysis of C–H Activation. ACS Catal 2022. [DOI: 10.1021/acscatal.2c02096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Aditya Nandy
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Husain Adamji
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - David W. Kastner
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Vyshnavi Vennelakanti
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Azadeh Nazemi
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Mingjie Liu
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Heather J. Kulik
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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16
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Nandy A, Duan C, Goffinet C, Kulik HJ. New Strategies for Direct Methane-to-Methanol Conversion from Active Learning Exploration of 16 Million Catalysts. JACS AU 2022; 2:1200-1213. [PMID: 35647589 PMCID: PMC9135396 DOI: 10.1021/jacsau.2c00176] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 04/12/2022] [Accepted: 04/15/2022] [Indexed: 05/03/2023]
Abstract
Despite decades of effort, no earth-abundant homogeneous catalysts have been discovered that can selectively oxidize methane to methanol. We exploit active learning to simultaneously optimize methane activation and methanol release calculated with machine learning-accelerated density functional theory in a space of 16 M candidate catalysts including novel macrocycles. By constructing macrocycles from fragments inspired by synthesized compounds, we ensure synthetic realism in our computational search. Our large-scale search reveals that low-spin Fe(II) compounds paired with strong-field (e.g., P or S-coordinating) ligands have among the best energetic tradeoffs between hydrogen atom transfer (HAT) and methanol release. This observation contrasts with prior efforts that have focused on high-spin Fe(II) with weak-field ligands. By decoupling equatorial and axial ligand effects, we determine that negatively charged axial ligands are critical for more rapid release of methanol and that higher-valency metals [i.e., M(III) vs M(II)] are likely to be rate-limited by slow methanol release. With full characterization of barrier heights, we confirm that optimizing for HAT does not lead to large oxo formation barriers. Energetic span analysis reveals designs for an intermediate-spin Mn(II) catalyst and a low-spin Fe(II) catalyst that are predicted to have good turnover frequencies. Our active learning approach to optimize two distinct reaction energies with efficient global optimization is expected to be beneficial for the search of large catalyst spaces where no prior designs have been identified and where linear scaling relationships between reaction energies or barriers may be limited or unknown.
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Affiliation(s)
- Aditya Nandy
- Department
of Chemical Engineering, Massachusetts Institute
of Technology, Cambridge, Massachusetts 02139, United States
- Department
of Chemistry, Massachusetts Institute of
Technology, Cambridge, Massachusetts 02139, United States
| | - Chenru Duan
- Department
of Chemical Engineering, Massachusetts Institute
of Technology, Cambridge, Massachusetts 02139, United States
- Department
of Chemistry, Massachusetts Institute of
Technology, Cambridge, Massachusetts 02139, United States
| | - Conrad Goffinet
- Department
of Chemical Engineering, Massachusetts Institute
of Technology, Cambridge, Massachusetts 02139, United States
| | - Heather J. Kulik
- Department
of Chemical Engineering, Massachusetts Institute
of Technology, Cambridge, Massachusetts 02139, United States
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17
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Cordes Née Kupper C, Klawitter I, Rüter I, Dechert S, Demeshko S, Ye S, Meyer F. Organometallic μ-Nitridodiiron Complexes in Oxidation States Ranging from (III/III) to (IV/IV). Inorg Chem 2022; 61:7153-7164. [PMID: 35475617 DOI: 10.1021/acs.inorgchem.2c00685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Iron complexes with nitrido ligands are of interest as molecular analogues of key intermediates during N2-to-NH3 conversion in industrial or enzymatic processes. Dinuclear iron complexes with a bridging nitrido unit are mostly known in relatively high oxidation states (III/IV or IV/IV), originating from the decomposition of azidoiron precursors via high-valent Fe≡N intermediates. The use of a tetra-NHC macrocyclic scaffold ligand (NHC = N-heterocyclic carbene) has now allowed for the isolation of a series of organometallic μ-nitridodiiron complexes ranging from the mid-valent FeIII-N-FeIII (1) via mixed-valent FeIII-N-FeIV (type 4) to the high-valent FeIV-N-FeIV (type 5) species that are interconverted at moderate potentials, accompanied by axial ligand binding at the FeIV sites. Magnetic measurements and electron paramagnetic resonance spectroscopy showed the homovalent complexes to be diamagnetic and the mixed-valent system to feature an S = 1/2 ground state due to very strong antiferromagnetic coupling. The bonding in the Fe-N-Fe moiety has been further probed by crystallographic structure determination, 57Fe Mössbauer and UV-vis spectroscopies, as well as density functional theory computations, which revealed high covalency and nearly identical Fe-N distances across this redox series. The latter has been rationalized in terms of the nonbonding nature of the combination of Fe dz2 atomic orbitals from which electrons are successively removed upon oxidation, and these redox processes are best described as being metal-centered. The tetra-NHC-ligated μ-nitridodiiron series complements a set of related complexes with single-atom μ-oxido and μ-phosphido bridges, but the Fe-N-Fe core exhibits a comparatively high stability over several oxidation states. This promises interesting applications in view of the manifold catalytic uses of μ-nitridodiiron complexes based on macrocyclic N-donor porphinato(2-) or phthalocyaninato(2-) ligands.
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Affiliation(s)
- Claudia Cordes Née Kupper
- Institute of Inorganic Chemistry, University of Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
| | - Iris Klawitter
- Institute of Inorganic Chemistry, University of Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
| | - Isabelle Rüter
- Institute of Inorganic Chemistry, University of Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
| | - Sebastian Dechert
- Institute of Inorganic Chemistry, University of Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
| | - Serhiy Demeshko
- Institute of Inorganic Chemistry, University of Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
| | - Shengfa Ye
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, People's Republic of China
| | - Franc Meyer
- Institute of Inorganic Chemistry, University of Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
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18
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Rosen AS, Notestein JM, Snurr RQ. Exploring mechanistic routes for light alkane oxidation with an iron-triazolate metal-organic framework. Phys Chem Chem Phys 2022; 24:8129-8141. [PMID: 35332353 DOI: 10.1039/d2cp00963c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this work, we computationally explore the formation and subsequent reactivity of various iron-oxo species in the iron-triazolate framework Fe2(μ-OH)2(bbta) (H2bbta = 1H,5H-benzo(1,2-d:4,5-d')bistriazole) for the catalytic activation of strong C-H bonds. With the direct conversion of methane to methanol as the probe reaction of interest, we use density functional theory (DFT) calculations to evaluate multiple mechanistic pathways in the presence of either N2O or H2O2 oxidants. These calculations reveal that a wide range of transition metal-oxo sites - both terminal and bridging - are plausible in this family of metal-organic frameworks, making it a unique platform for comparing the electronic structure and reactivity of different proposed active site motifs. Based on the DFT calculations, we predict that Fe2(μ-OH)2(bbta) would exhibit a relatively low barrier for N2O activation and energetically favorable formation of an [Fe(O)]2+ species that is capable of oxidizing C-H bonds. In contrast, the use of H2O2 as the oxidant is predicted to yield an assortment of bridging iron-oxo sites that are less reactive. We also find that abstracting oxo ligands can exhibit a complex mixture of both positive and negative spin density, which may have broader implications for relating the degree of radical character to catalytic activity. In general, we consider the coordinatively unsaturated iron sites to be promising for oxidation catalysis, and we provide several recommendations on how to further tune the catalytic properties of this family of metal-triazolate frameworks.
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Affiliation(s)
- Andrew S Rosen
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Rd., Evanston, IL 60208, USA.
| | - Justin M Notestein
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Rd., Evanston, IL 60208, USA.
| | - Randall Q Snurr
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Rd., Evanston, IL 60208, USA.
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19
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Basappa S, Bhawar R, Nagaraju DH, Bose SK. Recent advances in the chemistry of the phosphaethynolate and arsaethynolate anions. Dalton Trans 2022; 51:3778-3806. [PMID: 35108724 DOI: 10.1039/d1dt03994f] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Over the past decade, the reactivity of 2-phosphaethynolate (OCP-), a heavier analogue of the cyanate anion, has been the subject of momentous interest in the field of modern organometallic chemistry. It is used as a precursor to novel phosphorus-containing heterocycles and as a ligand in decarbonylative processes, serving as a synthetic equivalent of a phosphinidene derivative. This perspective aims to describe advances in the reactivities of phosphaethynolate and arsaethynolate anions (OCE-; E = P, As) with main-group element, transition metal, and f-block metal scaffolds. Further, the unique structures and bonding properties are discussed based on spectroscopic and theoretical studies.
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Affiliation(s)
- Suma Basappa
- Centre for Nano and Material Sciences (CNMS), Jain University, Jain Global Campus, Bangalore-562112, India.
| | - Ramesh Bhawar
- Centre for Nano and Material Sciences (CNMS), Jain University, Jain Global Campus, Bangalore-562112, India.
| | - D H Nagaraju
- Department of Chemistry, School of Applied Sciences, Reva University, Bangalore 560064, India.
| | - Shubhankar Kumar Bose
- Centre for Nano and Material Sciences (CNMS), Jain University, Jain Global Campus, Bangalore-562112, India.
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20
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Affiliation(s)
- Milica Feldt
- Leibniz Institute for Catalysis: Leibniz-Institut fur Katalyse eV Theory & Catalysis Albert-Einstein-Str 29A 18059 Rostock GERMANY
| | - Quan Manh Phung
- Nagoya University: Nagoya Daigaku Department of Chemistry JAPAN
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21
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Comba P, Nunn G, Scherz F, Walton PH. Intermediate-spin iron(IV)-oxido species with record reactivity. Faraday Discuss 2022; 234:232-244. [PMID: 35156976 DOI: 10.1039/d1fd00073j] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The nonheme iron(IV)-oxido complex trans-N3-[(L1)FeIVO(Cl)]+, where L1 is a derivative of the tetradentate bispidine 2,4-di(pyridine-2-yl)-3,7-diazabicyclo[3.3.1]nonane-1-one, has an S = 1 electronic ground state and is the most reactive nonheme iron model system known so far, of a similar order of reactivity as nonheme iron enzymes (C-H abstraction of cyclohexane, -90 °C (propionitrile), t1/2 = 3.5 s). The reaction with cyclohexane selectively leads to chlorocyclohexane, but "cage escape" at the [(L1)FeIII(OH)(Cl)]+/cyclohexyl radical intermediate lowers the productivity. Ligand field theory is used herein to analyze the d-d transitions of [(L1)FeIVO(X)]n+ (X = Cl-, Br-, MeCN) in comparison with the thoroughly characterized ferryl complex of tetramethylcyclam (TMC = L2; [(L2)FeIVO(MeCN)]2+). The ligand field parameters and d-d transition energies are shown to provide important information on the triplet-quintet gap and its correlation with oxidation reactivity.
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Affiliation(s)
- Peter Comba
- Universität Heidelberg, Anorganisch-Chemisches Institut, INF 270, D-69120 Heidelberg, Germany. .,Universität Heidelberg, Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR), Germany
| | - George Nunn
- Department of Chemistry, University of York, Heslington, YORK, YO10 5DD, UK
| | - Frederik Scherz
- Universität Heidelberg, Anorganisch-Chemisches Institut, INF 270, D-69120 Heidelberg, Germany.
| | - Paul H Walton
- Department of Chemistry, University of York, Heslington, YORK, YO10 5DD, UK
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22
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Saiz F, Bernasconi L. Catalytic properties of the ferryl ion in the solid state: a computational review. Catal Sci Technol 2022. [DOI: 10.1039/d2cy00200k] [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
This review summarises the last findings in the emerging field of heterogeneous catalytic oxidation of light alkanes by ferryl species supported on solid-state systems such as the conversion of methane into methanol by FeO-MOF74.
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Affiliation(s)
- Fernan Saiz
- ALBA Synchrotron, Carrer de la Llum 2-26, Cerdanyola del Valles 08290, Spain
| | - Leonardo Bernasconi
- Center for Research Computing and Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA
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23
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Zhang L, Sun LY, Chang JP, Xie HY, Zhang YW, Zhang YF, Han YF. A trefoil-shaped macrocycle with 12 imidazolium cations. CHINESE CHEM LETT 2022. [DOI: 10.1016/j.cclet.2022.01.064] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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24
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Bleher K, Comba P, Gross JH, Josephy T. ESI and tandem MS for mechanistic studies with high-valent transition metal species. Dalton Trans 2022; 51:8625-8639. [DOI: 10.1039/d2dt00809b] [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
The analysis of high-valent metal species has been in the focus of research for over 20 years. Mass spectrometry (MS) represents a technique routinely used for their characterization, in particular...
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25
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Bleher K, Comba P, Faltermeier D, Gupta A, Kerscher M, Krieg S, Martin B, Velmurugan G, Yang S. Non-Heme-Iron-Mediated Selective Halogenation of Unactivated Carbon-Hydrogen Bonds. Chemistry 2021; 28:e202103452. [PMID: 34792224 PMCID: PMC9300152 DOI: 10.1002/chem.202103452] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Indexed: 12/23/2022]
Abstract
Oxidation of the iron(II) precursor [(L1)FeIICl2], where L1 is a tetradentate bispidine, with soluble iodosylbenzene (sPhIO) leads to the extremely reactive ferryl oxidant [(L1)(Cl)FeIV=O]+ with a cis disposition of the chlorido and oxido coligands, as observed in non‐heme halogenase enzymes. Experimental data indicate that, with cyclohexane as substrate, there is selective formation of chlorocyclohexane, the halogenation being initiated by C−H abstraction and the result of a rebound of the ensuing radical to an iron‐bound Cl−. The time‐resolved formation of the halogenation product indicates that this primarily results from sPhIO oxidation of an initially formed oxido‐bridged diiron(III) resting state. The high yield of up to >70 % (stoichiometric reaction) as well as the differing reactivities of free Fe2+ and Fe3+ in comparison with [(L1)FeIICl2] indicate a high complex stability of the bispidine‐iron complexes. DFT analysis shows that, due to a large driving force and small triplet‐quintet gap, [(L1)(Cl)FeIV=O]+ is the most reactive small‐molecule halogenase model, that the FeIII/radical rebound intermediate has a relatively long lifetime (as supported by experimentally observed cage escape), and that this intermediate has, as observed experimentally, a lower energy barrier to the halogenation than the hydroxylation product; this is shown to primarily be due to steric effects.
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Affiliation(s)
- Katharina Bleher
- Universität Heidelberg, Anorganisch-Chemisches Institut und Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR), INF 270, 69120, Heidelberg, Germany
| | - Peter Comba
- Universität Heidelberg, Anorganisch-Chemisches Institut und Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR), INF 270, 69120, Heidelberg, Germany
| | - Dieter Faltermeier
- Universität Heidelberg, Anorganisch-Chemisches Institut und Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR), INF 270, 69120, Heidelberg, Germany
| | - Ashutosh Gupta
- Universität Heidelberg, Anorganisch-Chemisches Institut und Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR), INF 270, 69120, Heidelberg, Germany
| | - Marion Kerscher
- Universität Heidelberg, Anorganisch-Chemisches Institut und Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR), INF 270, 69120, Heidelberg, Germany
| | - Saskia Krieg
- Universität Heidelberg, Anorganisch-Chemisches Institut und Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR), INF 270, 69120, Heidelberg, Germany
| | - Bodo Martin
- Universität Heidelberg, Anorganisch-Chemisches Institut und Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR), INF 270, 69120, Heidelberg, Germany
| | - Gunasekaran Velmurugan
- Universität Heidelberg, Anorganisch-Chemisches Institut und Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR), INF 270, 69120, Heidelberg, Germany
| | - Shuyi Yang
- Universität Heidelberg, Anorganisch-Chemisches Institut und Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR), INF 270, 69120, Heidelberg, Germany
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26
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Fukuzumi S, Lee Y, Nam W. Deuterium kinetic isotope effects as redox mechanistic criterions. B KOREAN CHEM SOC 2021. [DOI: 10.1002/bkcs.12417] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Shunichi Fukuzumi
- Department of Chemistry and Nano Science Ewha Womans University Seoul Korea
- Faculty of Science and Engineering Meijo University Nagoya Aichi Japan
| | - Yong‐Min Lee
- Department of Chemistry and Nano Science Ewha Womans University Seoul Korea
- Research Institute for Basic Sciences Ewha Womans University Seoul Korea
| | - Wonwoo Nam
- Department of Chemistry and Nano Science Ewha Womans University Seoul Korea
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27
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Truong PT, Miller SG, McLaughlin Sta Maria EJ, Bowring MA. Large Isotope Effects in Organometallic Chemistry. Chemistry 2021; 27:14800-14815. [PMID: 34347912 DOI: 10.1002/chem.202102189] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Indexed: 01/24/2023]
Abstract
The kinetic isotope effect (KIE) is key to understanding reaction mechanisms in many areas of chemistry and chemical biology, including organometallic chemistry. This ratio of rate constants, kH /kD , typically falls between 1-7. However, KIEs up to 105 have been reported, and can even be so large that reactivity with deuterium is unobserved. We collect here examples of large KIEs across organometallic chemistry, in catalytic and stoichiometric reactions, along with their mechanistic interpretations. Large KIEs occur in proton transfer reactions such as protonation of organometallic complexes and clusters, protonolysis of metal-carbon bonds, and dihydrogen reactivity. C-H activation reactions with large KIEs occur with late and early transition metals, photogenerated intermediates, and abstraction by metal-oxo complexes. We categorize the mechanistic interpretations of large KIEs into the following three types: (a) proton tunneling, (b) compound effects from multiple steps, and (c) semi-classical effects on a single step. This comprehensive collection of large KIEs in organometallics provides context for future mechanistic interpretation.
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Affiliation(s)
- Phan T Truong
- Department of Chemistry, Reed College, 3203 SE Woodstock Blvd., Portland, OR 97222
| | - Sophia G Miller
- Department of Chemistry, Reed College, 3203 SE Woodstock Blvd., Portland, OR 97222
| | | | - Miriam A Bowring
- Department of Chemistry, Reed College, 3203 SE Woodstock Blvd., Portland, OR 97222
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28
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Lee JL, Ross DL, Barman SK, Ziller JW, Borovik AS. C-H Bond Cleavage by Bioinspired Nonheme Metal Complexes. Inorg Chem 2021; 60:13759-13783. [PMID: 34491738 DOI: 10.1021/acs.inorgchem.1c01754] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The functionalization of C-H bonds is one of the most challenging transformations in synthetic chemistry. In biology, these processes are well-known and are achieved with a variety of metalloenzymes, many of which contain a single metal center within their active sites. The most well studied are those with Fe centers, and the emerging experimental data show that high-valent iron oxido species are the intermediates responsible for cleaving the C-H bond. This Forum Article describes the state of this field with an emphasis on nonheme Fe enzymes and current experimental results that provide insights into the properties that make these species capable of C-H bond cleavage. These parameters are also briefly considered in regard to manganese oxido complexes and Cu-containing metalloenzymes. Synthetic iron oxido complexes are discussed to highlight their utility as spectroscopic and mechanistic probes and reagents for C-H bond functionalization. Avenues for future research are also examined.
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Affiliation(s)
- Justin L Lee
- Department of Chemistry, University of California-Irvine, 1102 Natural Sciences II, Irvine, California 92697, United States
| | - Dolores L Ross
- Department of Chemistry, University of California-Irvine, 1102 Natural Sciences II, Irvine, California 92697, United States
| | - Suman K Barman
- Department of Chemistry, University of California-Irvine, 1102 Natural Sciences II, Irvine, California 92697, United States
| | - Joseph W Ziller
- Department of Chemistry, University of California-Irvine, 1102 Natural Sciences II, Irvine, California 92697, United States
| | - A S Borovik
- Department of Chemistry, University of California-Irvine, 1102 Natural Sciences II, Irvine, California 92697, United States
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29
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Semiempirical method for examining asynchronicity in metal-oxido-mediated C-H bond activation. Proc Natl Acad Sci U S A 2021; 118:2108648118. [PMID: 34465626 DOI: 10.1073/pnas.2108648118] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The oxidation of substrates via the cleavage of thermodynamically strong C-H bonds is an essential part of mammalian metabolism. These reactions are predominantly carried out by enzymes that produce high-valent metal-oxido species, which are directly responsible for cleaving the C-H bonds. While much is known about the identity of these transient intermediates, the mechanistic factors that enable metal-oxido species to accomplish such difficult reactions are still incomplete. For synthetic metal-oxido species, C-H bond cleavage is often mechanistically described as synchronous, proton-coupled electron transfer (PCET). However, data have emerged that suggest that the basicity of the M-oxido unit is the key determinant in achieving enzymatic function, thus requiring alternative mechanisms whereby proton transfer (PT) has a more dominant role than electron transfer (ET). To bridge this knowledge gap, the reactivity of a monomeric MnIV-oxido complex with a series of external substrates was studied, resulting in a spread of over 104 in their second-order rate constants that tracked with the acidity of the C-H bonds. Mechanisms that included either synchronous PCET or rate-limiting PT, followed by ET, did not explain our results, which led to a proposed PCET mechanism with asynchronous transition states that are dominated by PT. To support this premise, we report a semiempirical free energy analysis that can predict the relative contributions of PT and ET for a given set of substrates. These findings underscore why the basicity of M-oxido units needs to be considered in C-H functionalization.
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30
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Nandy A, Duan C, Taylor MG, Liu F, Steeves AH, Kulik HJ. Computational Discovery of Transition-metal Complexes: From High-throughput Screening to Machine Learning. Chem Rev 2021; 121:9927-10000. [PMID: 34260198 DOI: 10.1021/acs.chemrev.1c00347] [Citation(s) in RCA: 70] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Transition-metal complexes are attractive targets for the design of catalysts and functional materials. The behavior of the metal-organic bond, while very tunable for achieving target properties, is challenging to predict and necessitates searching a wide and complex space to identify needles in haystacks for target applications. This review will focus on the techniques that make high-throughput search of transition-metal chemical space feasible for the discovery of complexes with desirable properties. The review will cover the development, promise, and limitations of "traditional" computational chemistry (i.e., force field, semiempirical, and density functional theory methods) as it pertains to data generation for inorganic molecular discovery. The review will also discuss the opportunities and limitations in leveraging experimental data sources. We will focus on how advances in statistical modeling, artificial intelligence, multiobjective optimization, and automation accelerate discovery of lead compounds and design rules. The overall objective of this review is to showcase how bringing together advances from diverse areas of computational chemistry and computer science have enabled the rapid uncovering of structure-property relationships in transition-metal chemistry. We aim to highlight how unique considerations in motifs of metal-organic bonding (e.g., variable spin and oxidation state, and bonding strength/nature) set them and their discovery apart from more commonly considered organic molecules. We will also highlight how uncertainty and relative data scarcity in transition-metal chemistry motivate specific developments in machine learning representations, model training, and in computational chemistry. Finally, we will conclude with an outlook of areas of opportunity for the accelerated discovery of transition-metal complexes.
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Affiliation(s)
- Aditya Nandy
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.,Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Chenru Duan
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.,Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Michael G Taylor
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Fang Liu
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Adam H Steeves
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Heather J Kulik
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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31
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Castillo CE, Gamba I, Vicens L, Clémancey M, Latour JM, Costas M, Basallote MG. Spin State Tunes Oxygen Atom Transfer towards Fe IV O Formation in Fe II Complexes. Chemistry 2021; 27:4946-4954. [PMID: 33350013 DOI: 10.1002/chem.202004921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Indexed: 11/08/2022]
Abstract
Oxoiron(IV) complexes bearing tetradentate ligands have been extensively studied as models for the active oxidants in non-heme iron-dependent enzymes. These species are commonly generated by oxidation of their ferrous precursors. The mechanisms of these reactions have seldom been investigated. In this work, the reaction kinetics of complexes [FeII (CH3 CN)2 L](SbF6 )2 ([1](SbF6 )2 and [2](SbF6 )2 ) and [FeII (CF3 SO3 )2 L] ([1](OTf)2 and [2](OTf)2 (1, L=Me,H Pytacn; 2, L=nP,H Pytacn; R,R' Pytacn=1-[(6-R'-2-pyridyl)methyl]-4,7- di-R-1,4,7-triazacyclononane) with Bu4 NIO4 to form the corresponding [FeIV (O)(CH3 CN)L]2+ (3, L=Me,H Pytacn; 4, L=nP,H Pytacn) species was studied in acetonitrile/acetone at low temperatures. The reactions occur in a single kinetic step with activation parameters independent of the nature of the anion and similar to those obtained for the substitution reaction with Cl- as entering ligand, which indicates that formation of [FeIV (O)(CH3 CN)L]2+ is kinetically controlled by substitution in the starting complex to form [FeII (IO4 )(CH3 CN)L]+ intermediates that are converted rapidly to oxo complexes 3 and 4. The kinetics of the reaction is strongly dependent on the spin state of the starting complex. A detailed analysis of the magnetic susceptibility and kinetic data for the triflate complexes reveals that the experimental values of the activation parameters for both complexes are the result of partial compensation of the contributions from the thermodynamic parameters for the spin-crossover equilibrium and the activation parameters for substitution. The observation of these opposite and compensating effects by modifying the steric hindrance at the ligand illustrates so far unconsidered factors governing the mechanism of oxygen atom transfer leading to high-valent iron oxo species.
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Affiliation(s)
- Carmen E Castillo
- Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica, y Química Inorgánica, Facultad de Ciencias, Instituto de Biomoléculas (INBIO), Universidad de Cádiz, Puerto Real, Cádiz, 11510, Spain
| | - Ilaria Gamba
- Grup de Química Bioinspirada, Supramolecular i Catàlisi (QBIS-CAT), Institut de Química Computacional i Catàlisi (IQCC), Departament de Química, Universitat de Girona, Campus de Montilivi, Girona, 17071, Catalonia, Spain
| | - Laia Vicens
- Grup de Química Bioinspirada, Supramolecular i Catàlisi (QBIS-CAT), Institut de Química Computacional i Catàlisi (IQCC), Departament de Química, Universitat de Girona, Campus de Montilivi, Girona, 17071, Catalonia, Spain
| | - Martin Clémancey
- CEA, CNRS, IRIG, DIESE, LCBM, Université Grenoble Alpes, pmb, 38000, Grenoble, France
| | - Jean-Marc Latour
- CEA, CNRS, IRIG, DIESE, LCBM, Université Grenoble Alpes, pmb, 38000, Grenoble, France
| | - Miquel Costas
- Grup de Química Bioinspirada, Supramolecular i Catàlisi (QBIS-CAT), Institut de Química Computacional i Catàlisi (IQCC), Departament de Química, Universitat de Girona, Campus de Montilivi, Girona, 17071, Catalonia, Spain
| | - Manuel G Basallote
- Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica, y Química Inorgánica, Facultad de Ciencias, Instituto de Biomoléculas (INBIO), Universidad de Cádiz, Puerto Real, Cádiz, 11510, Spain
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32
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Massie AA, Schremmer C, Rüter I, Dechert S, Siewert I, Meyer F. Selective Electrocatalytic CO 2 Reduction to CO by an NHC-Based Organometallic Heme Analogue. ACS Catal 2021. [DOI: 10.1021/acscatal.0c04518] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Allyssa A. Massie
- Institute of Inorganic Chemistry, University of Göttingen, D-37077 Göttingen, Germany
| | - Claudia Schremmer
- Institute of Inorganic Chemistry, University of Göttingen, D-37077 Göttingen, Germany
| | - Isabelle Rüter
- Institute of Inorganic Chemistry, University of Göttingen, D-37077 Göttingen, Germany
| | - Sebastian Dechert
- Institute of Inorganic Chemistry, University of Göttingen, D-37077 Göttingen, Germany
| | - Inke Siewert
- Institute of Inorganic Chemistry, University of Göttingen, D-37077 Göttingen, Germany
| | - Franc Meyer
- Institute of Inorganic Chemistry, University of Göttingen, D-37077 Göttingen, Germany
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33
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Keshari K, Bera M, Velasco L, Munshi S, Gupta G, Moonshiram D, Paria S. Characterization and reactivity study of non-heme high-valent iron-hydroxo complexes. Chem Sci 2021; 12:4418-4424. [PMID: 34163706 PMCID: PMC8179568 DOI: 10.1039/d0sc07054h] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A terminal FeIIIOH complex, [FeIII(L)(OH)]2− (1), has been synthesized and structurally characterized (H4L = 1,2-bis(2-hydroxy-2-methylpropanamido)benzene). The oxidation reaction of 1 with one equiv. of tris(4-bromophenyl)ammoniumyl hexachloroantimonate (TBAH) or ceric ammonium nitrate (CAN) in acetonitrile at −45 °C results in the formation of a FeIIIOH ligand radical complex, [FeIII(L˙)(OH)]− (2), which is hereby characterized by UV-visible, 1H nuclear magnetic resonance, electron paramagnetic resonance, and X-ray absorption spectroscopy techniques. The reaction of 2 with a triphenylcarbon radical further gives triphenylmethanol and mimics the so-called oxygen rebound step of Cpd II of cytochrome P450. Furthermore, the reaction of 2 was explored with different 4-substituted-2,6-di-tert-butylphenols. Based on kinetic analysis, a hydrogen atom transfer (HAT) mechanism has been established. A pKa value of 19.3 and a BDFE value of 78.2 kcal/mol have been estimated for complex 2. One-electron oxidation of an FeIII–OH complex (1) results in the formation of a FeIII–OH ligand radical complex (2). Its reaction with (C6H5)3C˙ results in the formation of (C6H5)3COH, which is a functional mimic of compound II of cytochrome P450.![]()
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Affiliation(s)
- Kritika Keshari
- Department of Chemistry, Indian Institute of Technology Delhi Hauz Khas New Delhi 110016 India
| | - Moumita Bera
- Department of Chemistry, Indian Institute of Technology Delhi Hauz Khas New Delhi 110016 India
| | - Lucía Velasco
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanociencia Calle Faraday, 9 28049 Madrid Spain
| | - Sandip Munshi
- School of Chemical Sciences, Indian Association for the Cultivation of Science 2A & 2B Raja S. C. Mullick Road, Jadavpur Kolkata 700032 India
| | - Geetika Gupta
- Department of Chemistry, Indian Institute of Technology Delhi Hauz Khas New Delhi 110016 India
| | - Dooshaye Moonshiram
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanociencia Calle Faraday, 9 28049 Madrid Spain
| | - Sayantan Paria
- Department of Chemistry, Indian Institute of Technology Delhi Hauz Khas New Delhi 110016 India
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Hua K, Gan MM, Liu XR, Zhang L, An YY, Han YF. Template-driven construction of [8]-imidazolium macrocycles. Org Chem Front 2021. [DOI: 10.1039/d0qo01617a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
A controllable and efficient template-driven strategy for the rational construction of polyimidazolium macrocycles has been developed.
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Affiliation(s)
- Kai Hua
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education
- College of Chemistry and Materials Science Northwest University
- Xi'an 710127
- P. R. China
| | - Ming-Ming Gan
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education
- College of Chemistry and Materials Science Northwest University
- Xi'an 710127
- P. R. China
| | - Xue-Ru Liu
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education
- College of Chemistry and Materials Science Northwest University
- Xi'an 710127
- P. R. China
| | - Le Zhang
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education
- College of Chemistry and Materials Science Northwest University
- Xi'an 710127
- P. R. China
| | - Yuan-Yuan An
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education
- College of Chemistry and Materials Science Northwest University
- Xi'an 710127
- P. R. China
| | - Ying-Feng Han
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education
- College of Chemistry and Materials Science Northwest University
- Xi'an 710127
- P. R. China
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35
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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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36
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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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37
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Nandy A, Kulik HJ. Why Conventional Design Rules for C–H Activation Fail for Open-Shell Transition-Metal Catalysts. ACS Catal 2020. [DOI: 10.1021/acscatal.0c04300] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Aditya Nandy
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Heather J. Kulik
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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38
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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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39
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Kumar R, Pandey B, Sen A, Ansari M, Sharma S, Rajaraman G. Role of oxidation state, ferryl-oxygen, and ligand architecture on the reactivity of popular high-valent FeIV=O species: A theoretical perspective. Coord Chem Rev 2020. [DOI: 10.1016/j.ccr.2020.213397] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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40
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Yu C, Zhong M, Zhang Y, Wei J, Ma W, Zhang W, Ye S, Xi Z. Butadienyl Diiron Complexes: Nonplanar Metalla‐Aromatics Involving σ‐Type Orbital Overlap. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202008986] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Chao Yu
- Beijing National Laboratory for Molecular Sciences (BNLMS) Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education College of Chemistry Peking University Beijing 100871 China
| | - Mingdong Zhong
- Beijing National Laboratory for Molecular Sciences (BNLMS) Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education College of Chemistry Peking University Beijing 100871 China
| | - Yongliang Zhang
- Beijing National Laboratory for Molecular Sciences (BNLMS) Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education College of Chemistry Peking University Beijing 100871 China
| | - Junnian Wei
- Beijing National Laboratory for Molecular Sciences (BNLMS) Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education College of Chemistry Peking University Beijing 100871 China
| | - Wangyang Ma
- Beijing National Laboratory for Molecular Sciences (BNLMS) Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education College of Chemistry Peking University Beijing 100871 China
| | - Wen‐Xiong Zhang
- Beijing National Laboratory for Molecular Sciences (BNLMS) Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education College of Chemistry Peking University Beijing 100871 China
| | - Shengfa Ye
- State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences 457 Zhongshan Road Dalian 116023 China
- Max-Planck-Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
| | - Zhenfeng Xi
- Beijing National Laboratory for Molecular Sciences (BNLMS) Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education College of Chemistry Peking University Beijing 100871 China
- State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic Chemistry Shanghai 200032 China
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Yu C, Zhong M, Zhang Y, Wei J, Ma W, Zhang WX, Ye S, Xi Z. Butadienyl Diiron Complexes: Nonplanar Metalla-Aromatics Involving σ-Type Orbital Overlap. Angew Chem Int Ed Engl 2020; 59:19048-19053. [PMID: 32686269 DOI: 10.1002/anie.202008986] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Indexed: 01/15/2023]
Abstract
A new class of nonplanar metalla-aromatics, diiron complexes bridged by a 1,3-butadienyl dianionic ligand, were synthesized in high yields from dilithio reagents and two equivalents of FeBr2 . The complexes consist of two antiferromagnetically coupled high-spin FeII centers, as revealed by magnetometry, Mössbauer spectroscopy, and DFT calculations. Furthermore, experimental (X-ray structural analysis) and theoretical analyses (NICS, ICSS, AICD, MOs) suggest that the complexes are aromatic. Remarkably, this nonplanar metalla-aromaticity is achieved by an uncommon σ-type overlap between the ligand p and metal d orbitals, in sharp contrast to the intensively studied planar aromatic systems featuring delocalized π-type bonding. Specifically, the σ-type interaction between the two Fe 3dxz orbitals and the butadienyl π orbital results in the formation of a six-electron conjugated system and hence enables the aromatic character.
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Affiliation(s)
- Chao Yu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing, 100871, China
| | - Mingdong Zhong
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing, 100871, China
| | - Yongliang Zhang
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing, 100871, China
| | - Junnian Wei
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing, 100871, China
| | - Wangyang Ma
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing, 100871, China
| | - Wen-Xiong Zhang
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing, 100871, China
| | - Shengfa Ye
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, China.,Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Zhenfeng Xi
- Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing, 100871, China.,State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Shanghai, 200032, China
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42
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Mayfield JR, Grotemeyer EN, Jackson TA. Concerted proton-electron transfer reactions of manganese-hydroxo and manganese-oxo complexes. Chem Commun (Camb) 2020; 56:9238-9255. [PMID: 32578605 PMCID: PMC7429365 DOI: 10.1039/d0cc01201g] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The enzymes manganese superoxide dismutase and manganese lipoxygenase use MnIII-hydroxo centres to mediate proton-coupled electron transfer (PCET) reactions with substrate. As manganese is earth-abundant and inexpensive, manganese catalysts are of interest for synthetic applications. Recent years have seen exciting reports of enantioselective C-H bond oxidation by Mn catalysts supported by aminopyridyl ligands. Such catalysts offer economic and environmentally-friendly alternatives to conventional reagents and catalysts. Mechanistic studies of synthetic catalysts highlight the role of Mn-oxo motifs in attacking substrate C-H bonds, presumably by a concerted proton-electron transfer (CPET) step. (CPET is a sub-class of PCET, where the proton and electron are transferred in the same step.) Knowledge of geometric and electronic influences for CPET reactions of Mn-hydroxo and Mn-oxo adducts enhances our understanding of biological and synthetic manganese centers and informs the design of new catalysts. In this Feature article, we describe kinetic, spectroscopic, and computational studies of MnIII-hydroxo and MnIV-oxo complexes that provide insight into the basis for the CPET reactivity of these species. Systematic perturbations of the ligand environment around MnIII-hydroxo and MnIV-oxo motifs permit elucidation of structure-activity relationships. For MnIII-hydroxo centers, electron-deficient ligands enhance oxidative reactivity. However, ligand perturbations have competing consequences, as changes in the MnIII/II potential, which represents the electron-transfer component for CPET, is offset by compensating changes in the pKa of the MnII-aqua product, which represents the proton-transfer component for CPET. For MnIV-oxo systems, a multi-state reactivity model inspired the development of significantly more reactive complexes. Weakened equatorial donation to the MnIV-oxo unit results in large rate enhancements for C-H bond oxidation and oxygen-atom transfer reactions. These results demonstrate that the local coordination environment can be rationally changed to enhance reactivity of MnIII-hydroxo and MnIV-oxo adducts.
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Affiliation(s)
- Jaycee R Mayfield
- Department of Chemistry and Center for Environmentally Beneficial Catalysis, University of Kansas, Lawrence, KS 66045, USA.
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Roy L. Theoretical Identification of the Factors Governing the Reactivity of C-H Bond Activation by Non-Heme Iron(IV)-Oxo Complexes. Chempluschem 2020; 84:893-906. [PMID: 31943994 DOI: 10.1002/cplu.201900178] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/30/2019] [Indexed: 11/06/2022]
Abstract
Selective functionalization of C-H bonds provides a straightforward approach to a large variety of well-defined derivatives. High-valent mononuclear iron(IV)-oxo complexes are proposed to carry out these C-H activation reactions in enzymes or in biomimetic syntheses. In this Minireview, we aim to highlight the features that delineate the distinct reactivity of non-heme oxo-iron(IV) motifs to cleave strong C-H bonds in hydrocarbons, primarily focusing on the hydrogen atom transfer (HAT) process. We describe how the structural and electronic properties of supporting ligands modulate the oxidative property of the iron(IV)-oxo complexes. Furthermore, we highlight the decisive role played by spin-state in these biomimetic reactions. We also discuss how tunneling and external perturbations like electric field influence the transfer of hydrogen atoms. Lastly, we emphasize how computations could work as a practical guide to sketch and develop synthetic models with greater efficacy.
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Affiliation(s)
- Lisa Roy
- Institute of Chemical Technology Mumbai IOC Odisha Campus Bhubaneswar, IIT Kharagpur Extension Centre, Bhubaneswar, 751013, Odisha, India
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44
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Maldonado-Domínguez M, Srnec M. Understanding and Predicting Post H-Atom Abstraction Selectivity through Reactive Mode Composition Factor Analysis. J Am Chem Soc 2020; 142:3947-3958. [PMID: 32000494 DOI: 10.1021/jacs.9b12800] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The selective functionalization of C-H bonds is one of the Grails of synthetic chemistry. In this work, we demonstrate that the selectivity toward fast hydroxylation or radical diffusion (known as the OH-rebound and dissociation mechanisms) following H-atom abstraction (HAA) from a substrate C-H bond by high-valent iron-oxo oxidants is already encoded in the HAA step when the post-HAA barriers are much lower than the preceding one. By applying the reactive mode composition factor (RMCF) analysis, which quantifies the kinetic energy distribution (KED) at the reactive mode (RM) of transition states, we show that reactions following the OH-rebound coordinate concentrate the RM kinetic energy on the motion of the reacting oxygen atom and the nascent substrate radical, whereas reactions following the dissociation channel localize most of their kinetic energy in H-atom motion. These motion signatures serve to predict the post-HAA selectivity, and since KED is affected by the free energy of reaction and asynchronicity (factor η) of HAA, we show that bimolecular HAA reactions in solution that are electron transfer-driven and highly exergonic have the lowest fraction of KED on the transferred H-atom and the highest chance to follow rebound hydroxylation. Finally, the RMCF analysis predicts that the H/D primary kinetic isotope effect can serve as a probe for these mechanisms, as confirmed in virtually all reported examples in the literature.
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Affiliation(s)
- Mauricio Maldonado-Domínguez
- J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences , Dolejškova 3 , Prague 8 18223 , Czech Republic
| | - Martin Srnec
- J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences , Dolejškova 3 , Prague 8 18223 , Czech Republic
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45
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Stoneburner SJ, Truhlar DG, Gagliardi L. Transition Metal Spin-State Energetics by MC-PDFT with High Local Exchange. J Phys Chem A 2020; 124:1187-1195. [PMID: 31962045 DOI: 10.1021/acs.jpca.9b10772] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The energetics of the spin states of transition metal complexes have been explored with a variety of electronic structure methods, but the calculations require a compromise between accuracy and affordability. In this work, the spin splittings of several iron complexes are studied with multiconfiguration pair-density functional theory (MC-PDFT). The results are compared to previously published results obtained by complete active space second-order perturbation theory (CASPT2) and CASPT2 with coupled-cluster semicore correlation (CASPT2/CC). In contrast to CASPT2's systematic overstabilization of high-spin states with respect to the CASPT2/CC reference, MC-PDFT with the tPBE on-top functional understabilizes high-spin states. This systematic understabilization is largely corrected by revising the exchange and correlation contributions to the on-top functional using the high local-exchange approximation (tPBE-HLE). Moreover, tPBE-HLE correctly predicts the spin of the ground state in most cases, while CASPT2 incorrectly predicts high-spin ground states in all cases. This is encouraging for practical work because tPBE and tPBE-HLE are faster than CASPT2 by a factor of 50 even in a moderately sized example.
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Affiliation(s)
- Samuel J Stoneburner
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute , University of Minnesota , 207 Pleasant Street SE , Minneapolis , Minnesota 55455-0431 , United States
| | - Donald G Truhlar
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute , University of Minnesota , 207 Pleasant Street SE , Minneapolis , Minnesota 55455-0431 , United States
| | - Laura Gagliardi
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute , University of Minnesota , 207 Pleasant Street SE , Minneapolis , Minnesota 55455-0431 , United States
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46
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Liu Z, Lu Y, Guo J, Hu W, Dang Y, Wang ZX. DFT Mechanistic Account for the Site Selectivity of Electron-Rich C(sp 3)-H Bond in the Manganese-Catalyzed Aminations. Org Lett 2020; 22:453-457. [PMID: 31913046 DOI: 10.1021/acs.orglett.9b04215] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
DFT study suggests that the C-H cleavage involved in the C(sp3)-H amination catalyzed by manganese perchlorophthalocyanine complex [MnIII(ClPc)]+ proceeds via hydride transfer (HYT), instead of hydrogen atom transfer (HAT), thus elucidating why the reaction favors aminating the electron-rich C-H bond, rather than that with smaller bond dissociation energy preferred by HAT. Detailed analyses indicate the HYT actually occurs via concerted electron and hydrogen atom transfers and the redox-active ClPc ligand enables the HYT.
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Affiliation(s)
- Zheyuan Liu
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry , Tianjin University , Tianjin 300072 , China
| | - Yu Lu
- School of Chemical Sciences , University of the Chinese Academy of Sciences , Beijing 100049 , China
| | - Jiandong Guo
- School of Chemical Sciences , University of the Chinese Academy of Sciences , Beijing 100049 , China
| | - Wenping Hu
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry , Tianjin University , Tianjin 300072 , China
| | - Yanfeng Dang
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry , Tianjin University , Tianjin 300072 , China
| | - Zhi-Xiang Wang
- School of Chemical Sciences , University of the Chinese Academy of Sciences , Beijing 100049 , China
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47
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Zhang WJ, Wang GJ, Zhang P, Zou W, Hu SX. The decisive role of 4f-covalency in the structural direction and oxidation state of XPrO compounds (X: group 13 to 17 elements). Phys Chem Chem Phys 2020; 22:27746-27756. [PMID: 33242323 DOI: 10.1039/d0cp04700g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Lanthanide oxo compounds are of vital importance in lanthanide chemistry, as well as in environmental and materials sciences. Praseodymium, as an exceptional element in lanthanides which can form a +V formal oxidation state (OSf) besides the dominant +III among the 4f-block element, displays the significant participation of the Pr 4f orbitals in bonding interactions which is commonly crucial in stabilizing the high oxidation state of Pr in PrO2+ and NPrO species. Here, we report a systematic theoretical study on the structures and stabilities of a series of XPrO (X: B, Al, C, Si, N, P, As, O, S, F, Cl) compounds along with [XPrO]+ cation (X: O, S) and [X3PrO] complexes (X: F and Cl). This work reveals that Pr is able to achieve the lowest and highest OSf and the OSf exhibits periodic variation from +I in BOPr and AlOPr to +II in SiOPr to +III in CPrO, FPrO, ClPrO and AsPrO to +IV in OPrO and SPrO and even to +V in NPrO, [OPrO]+, [SPrO]+, F3PrO and Cl3PrO. We found that the molecular structures are correlated to the Pr oxidation state due to the highly important 4f orbital in the chemical bonding of the high oxidation state compounds. Thus, not only the electronegativity of the ligand but also the quasi-degenerate Pr valence 4f orbitals, namely energetic covalency, control the oxidation state and play a fundamental role in affecting the electronic structural stability of Pr(v) compounds as well. This work demonstrates the structurally directing role of the f-orbital in the formation of the linear structure and is constructive for achieving the higher oxidation state of a given element by tuning the ligand.
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Affiliation(s)
- Wen-Jing Zhang
- Beijing Computational Science Research Center, Beijing 100193, China.
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48
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Ghosh B, Banerjee A, Paul A. Understanding the Role of Solvents and Spin-Orbit Coupling in an Oxygen-Assisted S N 2-Type Oxidative Transmetalation Reaction. Chemistry 2019; 25:16606-16616. [PMID: 31625633 DOI: 10.1002/chem.201903281] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 10/18/2019] [Indexed: 01/24/2023]
Abstract
The aerial oxidation of PdII to PdIV has emerged as an integral component of sustainable catalytic C-H functionalization processes. However, a proper understanding of the factors that control the viability of this oxidative process remains elusive. An investigation of the intricate mechanism of the transmetalation reaction of the aerial oxidative transformation of [(Me3 tacn)PdII Me2 ] (Me3 tacn=N,N',N''-trimethyl-1,4,7-triazacyclononane) to [(Me3 tacn)PdIV Me3 ]+ has been conducted by using DFT, along with multireference methods, such as second-order n-electron valence-state perturbation theory (NEVPT2) with complete active space self-consistent field theory (CASSCF). The present endeavor predicts that the thermodynamics and kinetics of the oxygen activation step are primarily dictated by the polarity of the solvents, which determine the amount of charge transfer to the oxygen molecule from the PdII center. Additionally, it is observed that the presence of a protic solvent has a significant effect on the spin-orbit coupling term at the minimum energy crossing point of the triplet and singlet surfaces. Moreover, it is shown that the intermetal ligand-transfer phenomenon is an important instance of an oxygen-assisted SN 2 reaction.
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Affiliation(s)
- Boyli Ghosh
- School of Chemical Science, Indian Association for the Cultivation of Science, 2A & 2B, Raja S.C. Mullick Road, Kolkata, 700032, India
| | - Ambar Banerjee
- Department of Organic Chemistry, Weizmann Institute of Science, Kimmelman 26, 7610001, Rehovot, Israel
| | - Ankan Paul
- School of Chemical Science, Indian Association for the Cultivation of Science, 2A & 2B, Raja S.C. Mullick Road, Kolkata, 700032, India
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49
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Rice DB, Massie AA, Jackson TA. Experimental and Multireference ab Initio Investigations of Hydrogen-Atom-Transfer Reactivity of a Mononuclear MnIV-oxo Complex. Inorg Chem 2019; 58:13902-13916. [DOI: 10.1021/acs.inorgchem.9b01761] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Derek B. Rice
- Department of Chemistry and Center for Environmentally Beneficial Catalysis, The University of Kansas, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States
| | - Allyssa A. Massie
- Department of Chemistry and Center for Environmentally Beneficial Catalysis, The University of Kansas, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States
| | - Timothy A. Jackson
- Department of Chemistry and Center for Environmentally Beneficial Catalysis, The University of Kansas, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States
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50
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Ghosh M, Cramer HH, Dechert S, Demeshko S, John M, Hansmann MM, Ye S, Meyer F. A μ-Phosphido Diiron Dumbbell in Multiple Oxidation States. Angew Chem Int Ed Engl 2019; 58:14349-14356. [PMID: 31350785 PMCID: PMC6790664 DOI: 10.1002/anie.201908213] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Indexed: 11/06/2022]
Abstract
The reaction of the ferrous complex [LFe(NCMe)2 ](OTf)2 (1), which contains a macrocyclic tetracarbene as ligand (L), with Na(OCP) generates the OCP- -ligated complex [LFe(PCO)(CO)]OTf (2) together with the dinuclear μ-phosphido complex [(LFe)2 P](OTf)3 (3), which features an unprecedented linear Fe-(μ-P)-Fe motif and a "naked" P-atom bridge that appears at δ=+1480 ppm in the 31 P NMR spectrum. 3 exhibits rich redox chemistry, and both the singly and doubly oxidized species 4 and 5 could be isolated and fully characterized. X-ray crystallography, spectroscopic studies, in combination with DFT computations provide a comprehensive electronic structure description and show that the Fe-(μ-P)-Fe core is highly covalent and structurally invariant over the series of oxidation states that are formally described as ranging from FeIII FeIII to FeIV FeIV . 3-5 now add a higher homologue set of complexes to the many systems with Fe-(μ-O)-Fe and Fe-(μ-N)-Fe core structures that are prominent in bioinorganic chemistry and catalysis.
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Affiliation(s)
- Munmun Ghosh
- Institut für Anorganische ChemieGeorg-August-Universität GöttingenTammannstrasse 437077GöttingenGermany
| | - Hanna H. Cramer
- Max-Planck Institut für Chemische EnergiekonversionStiftstrasse 34–3645470Mülheim an der RuhrGermany
| | - Sebastian Dechert
- Institut für Anorganische ChemieGeorg-August-Universität GöttingenTammannstrasse 437077GöttingenGermany
| | - Serhiy Demeshko
- Institut für Anorganische ChemieGeorg-August-Universität GöttingenTammannstrasse 437077GöttingenGermany
| | - Michael John
- Institut für Anorganische ChemieGeorg-August-Universität GöttingenTammannstrasse 437077GöttingenGermany
| | - Max M. Hansmann
- Institut für Organische und Biomolekulare ChemieGeorg-August-Universität GöttingenTammannstrasse 237077GöttingenGermany
| | - Shengfa Ye
- Max-Planck Institut für KohlenforschungStiftstrasse 34–3645470Mülheim an der RuhrGermany
| | - Franc Meyer
- Institut für Anorganische ChemieGeorg-August-Universität GöttingenTammannstrasse 437077GöttingenGermany
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