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Depenbrock F, Limpke T, Stammler A, Oldengott J, Bögge H, Glaser T. Increasing the electron donation in a dinucleating ligand family: molecular and electronic structures in a series of Co IICo II complexes. Dalton Trans 2024; 53:9554-9567. [PMID: 38771300 DOI: 10.1039/d4dt00877d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
We have developed a family of dinucleating ligands with varying terminal donors to generate dinuclear peroxo and high-valent complexes and to correlate their stabilities and reactivities with their molecular and electronic structures as a function of the terminal donors. It appears that the electron-donating ability of the terminal donors is an important handle for controlling these stabilities and reactivities. Here, we present the synthesis of a new dinucleating ligand with potentially strong donating terminal imidazole donors. As CoII ions are sensitive to variations in donor strength in terms of coordination number, magnetism, UV-Vis-NIR spectra, redox potentials, we probe the electron donation ability of this new ligand in CoIICoII complexes in comparison to the parent CoIICoII complexes with terminal pyridine donors and we synthesize the analogous CoIICoII complexes with terminal 6-methylpyridines and methoxy-substituted pyridines. The molecular structures show indeed strong variations in coordination numbers and bond lengths. These differences in the molecular structures are reflected in the magnetic properties and in the d-d transitions demonstrating that the molecular structures remain intact upon dissolution. The redox potentials are analyzed with respect to the electron donation ability and are the only handle to observe an effect of the methoxy-substituted pyridines. All data taken together show the following order of electron donating ability for the terminal donors: 6-methylpyridines ≪ pyridines < methoxy-substituted pyridines ≪ imidazoles.
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Affiliation(s)
- Felix Depenbrock
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany.
| | - Thomas Limpke
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany.
| | - Anja Stammler
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany.
| | - Jan Oldengott
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany.
| | - Hartmut Bögge
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany.
| | - Thorsten Glaser
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany.
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2
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Kajita Y, Kubo M, Arii H, Ishikawa S, Saito Y, Wasada-Tsutsui Y, Funahashi Y, Ozawa T, Masuda H. Preparations of trans- and cis- μ-1,2-Peroxodiiron(III) Complexes. Molecules 2023; 29:205. [PMID: 38202788 PMCID: PMC10780643 DOI: 10.3390/molecules29010205] [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: 12/06/2023] [Revised: 12/20/2023] [Accepted: 12/28/2023] [Indexed: 01/12/2024] Open
Abstract
The iron(II) complex with cis,cis-1,3,5-tris(benzylamino)cyclohexane (Bn3CY) (1) has been synthesized and characterized, which reacted with dioxygen to form the peroxo complex 2 in acetone at -60 °C. On the basis of spectroscopic measurements for 2, it was confirmed that the peroxo complex 2 has a trans-μ-1,2 fashion. Additionally, the peroxo complex 2 was reacted with benzoate anion as a bridging agent to give a peroxo complex 3. The results of resonance Raman and 1H-NMR studies supported that the peroxo complex 3 is a cis-μ-1,2-peroxodiiron(III) complex. These spectral features were interpreted by using DFT calculations.
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Affiliation(s)
- Yuji Kajita
- Department of Applied Chemistry, Graduate School of Engineering, Aichi Institute of Technology, 1247 Yachigusa, Yakusa-cho, Toyota 470-0392, Japan;
| | - Masaki Kubo
- Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555, Japan; (M.K.); (Y.W.-T.); (T.O.)
| | - Hidekazu Arii
- Department of Education, Graduate School of Education, University of Miyazaki, Gakuenkibanadai-Nishi, Miyazaki 889-2192, Japan;
| | - Shinya Ishikawa
- Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555, Japan; (M.K.); (Y.W.-T.); (T.O.)
| | - Yamato Saito
- Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555, Japan; (M.K.); (Y.W.-T.); (T.O.)
| | - Yuko Wasada-Tsutsui
- Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555, Japan; (M.K.); (Y.W.-T.); (T.O.)
| | - Yasuhiro Funahashi
- Department of Chemistry, Graduate School of Science, Osaka University, Machikaneyama, Toyonaka, Osaka 560-0043, Japan;
| | - Tomohiro Ozawa
- Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555, Japan; (M.K.); (Y.W.-T.); (T.O.)
| | - Hideki Masuda
- Department of Applied Chemistry, Graduate School of Engineering, Aichi Institute of Technology, 1247 Yachigusa, Yakusa-cho, Toyota 470-0392, Japan;
- Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555, Japan; (M.K.); (Y.W.-T.); (T.O.)
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3
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Sarkar A, Das S, Mondal P, Maiti B, Sen Gupta S. Synthesis, Characterization, and Reactivity of High-Valent Carbene Dicarboxamide-Based Nickel Pincer Complexes. Inorg Chem 2023. [PMID: 38001041 DOI: 10.1021/acs.inorgchem.3c03465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2023]
Abstract
High-valent metal-fluoride complexes are currently being explored for concerted proton-electron transfer (CPET) reactions, the driving force being the high bond dissociation energy of H-F (BDEH-F = 135 kcal/mol) that is formed after the reaction. Ni(III)-fluoride-based complexes on the pyridine dicarboxamide pincer ligand framework have been utilized for CPET reactions toward phenols and hydrocarbons. We have replaced the central pyridine ligand with an N-heterocyclic carbene carbene to probe its effect in both stabilizing the high-valent Ni(III) state and its ability to initiate CPET reactions. We report a monomeric carbene-diamide-based Ni(II)-fluoride pincer complex that was characterized through 1H/19F NMR, mass spectrometry, UV-vis, and X-ray crystallography analysis. Although carbenes and deprotonated carboxamides in the Ni(II)-fluoride complex are expected to stabilize the Ni(III) state upon oxidation, the Ni(III)/Ni(II) redox process occurred at very high potential (0.87 V vs Fc+/Fc, dichloromethane) and was irreversible. Structural studies indicate significant distortion in the imidazolium "NCN" carbene plane of Ni(II)-fluoride caused by the formation of six-membered metallacycles. The high-valent NiIII-fluoride analogue was synthesized by the addition of 1.0 equiv CTAN (ceric tetrabutylammonium nitrate) in dichloromethane at -20 °C which was characterized by UV-vis, mass spectrometry, and EPR spectroscopy. Density functional theory studies indicate that the Ni-carbene bond elongated, while the Ni-F bond shortened upon oxidation to the Ni(III) species. The high-valent Ni(III)-fluoride was found to react with the substituted phenols. Analysis of the KIE and linear free energy relationship correlates well with the CPET nature of the reaction. Preliminary analysis indicates that the CPET is asynchronous and is primarily driven by the E0' of the Ni(III)-fluoride complex.
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Affiliation(s)
- Aniruddha Sarkar
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, India
| | - Soumadip Das
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, India
| | - Prasenjit Mondal
- Department of Chemistry, Indian Institute of Technology Tirupati (IIT Tirupati), Tirupati, AP 517619, India
| | - Biswajit Maiti
- Department of Chemistry, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | - Sayam Sen Gupta
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, India
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4
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Ajaykamal T, Palaniandavar M. Mononuclear nickel(ii)-flavonolate complexes of tetradentate tripodal 4N ligands as structural and functional models for quercetin 2,4-dioxygenase: structures, spectra, redox and dioxygenase activity. RSC Adv 2023; 13:24674-24690. [PMID: 37601601 PMCID: PMC10436029 DOI: 10.1039/d3ra04834a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 08/01/2023] [Indexed: 08/22/2023] Open
Abstract
Three new nickel(ii)-flavonolate complexes of the type [Ni(L)(fla)](ClO4) 1-3, where L is the tripodal 4N ligand tris(pyrid-2-ylmethyl)amine (tpa, L1) or (pyrid-2-ylmethyl)bis(6-methylpyrid-2-ylmethyl)amine (6-Me2-tpa, L2) or tris(N-Et-benzimidazol-2-ylmethyl)amine (Et-ntb, L3), have been isolated as functional models for Ni(ii)-containing quercetin 2,4-dioxygenase. Single crystal X-ray structures of 1 and 3 reveal that Ni(ii) is involved in π-back bonding with flavonolate (fla-), as evident from enhancement in C[double bond, length as m-dash]O bond length upon coordination [H(fla), 1.232(3); 1, 1.245(7); 3, 1.262(8) Å]. More asymmetric chelation of fla- in 3 than in 1 [Δd = (Ni-Ocarbonyl - Ni-Oenolate): 1, 0.126; 3, 0.182 Å] corresponds to lower π-delocalization in 3 with electron-releasing N-Et substituent. The optimized structures of 1-3 and their geometrical isomers have been computed by DFT methods. The HOMO and LUMO, both localized on Ni(ii)-bound fla-, are highly conjugated bonding π- and antibonding π*-orbitals respectively. They are located higher in energy than the Ni(ii)-based MOs (HOMO-1, dx2-y2; HOMO-2/6, dz2), revealing that the Ni(ii)-bound fla- rather than Ni(ii) would undergo oxidation upon exposure to dioxygen. The results of computational studies, in combination with spectral and electrochemical studies, support the involvement of redox-inactive Ni(ii) in π-back bonding with fla-, tuning the π-delocalization in fla- and hence its activation. Upon exposure to dioxygen, all the flavonolate adducts in DMF solution decompose to produce CO and depside, which then is hydrolyzed to give the corresponding acids at 70 °C. The highest rate of dioxygenase reactivity of 3 (kO2: 3 (29.10 ± 0.16) > 1 (16.67 ± 0.70) > 2 (1.81 ± 0.04 × 10-1 M-1 s-1)), determined by monitoring the disappearance of the LMCT band in the range 440-450 nm, is ascribed to the electron-releasing N-Et substituent on bzim ring, which decreases the π-delocalization in fla- and enhances its activation.
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Affiliation(s)
- Tamilarasan Ajaykamal
- Department of Chemistry, Bharathidasan University Tiruchirapalli 620 024 Tamil Nadu India +91-431-2407043 +91-431-2407125
| | - Mallayan Palaniandavar
- Department of Chemistry, Bharathidasan University Tiruchirapalli 620 024 Tamil Nadu India +91-431-2407043 +91-431-2407125
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5
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Jeong D, Selverstone Valentine J, Cho J. Bio-inspired mononuclear nonheme metal peroxo complexes: Synthesis, structures and mechanistic studies toward understanding enzymatic reactions. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2023.215021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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6
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Kass D, Yao S, Krause KB, Corona T, Richter L, Braun T, Mebs S, Haumann M, Dau H, Lohmiller T, Limberg C, Drieß M, Ray K. Spectroscopic Properties of a Biologically Relevant [Fe 2 (μ-O) 2 ] Diamond Core Motif with a Short Iron-Iron Distance. Angew Chem Int Ed Engl 2023; 62:e202209437. [PMID: 36541062 DOI: 10.1002/anie.202209437] [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: 06/29/2022] [Revised: 12/05/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022]
Abstract
Diiron cofactors in enzymes perform diverse challenging transformations. The structures of high valent intermediates (Q in methane monooxygenase and X in ribonucleotide reductase) are debated since Fe-Fe distances of 2.5-3.4 Å were attributed to "open" or "closed" cores with bridging or terminal oxido groups. We report the crystallographic and spectroscopic characterization of a FeIII 2 (μ-O)2 complex (2) with tetrahedral (4C) centres and short Fe-Fe distance (2.52 Å), persisting in organic solutions. 2 shows a large Fe K-pre-edge intensity, which is caused by the pronounced asymmetry at the TD FeIII centres due to the short Fe-μ-O bonds. A ≈2.5 Å Fe-Fe distance is unlikely for six-coordinate sites in Q or X, but for a Fe2 (μ-O)2 core containing four-coordinate (or by possible extension five-coordinate) iron centres there may be enough flexibility to accommodate a particularly short Fe-Fe separation with intense pre-edge transition. This finding may broaden the scope of models considered for the structure of high-valent diiron intermediates formed upon O2 activation in biology.
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Affiliation(s)
- Dustin Kass
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
| | - Shenglai Yao
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 115, 10623, Berlin, Germany
| | - Konstantin B Krause
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
| | - Teresa Corona
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
| | - Liza Richter
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
| | - Thomas Braun
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
| | - Stefan Mebs
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Michael Haumann
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Holger Dau
- Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Thomas Lohmiller
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany.,EPR4Energy Joint Lab, Department Spins in Energy Conversion and Quantum Information Science, Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 16, 12489, Berlin, Germany
| | - Christian Limberg
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
| | - Matthias Drieß
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 115, 10623, Berlin, Germany
| | - Kallol Ray
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
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7
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Sarkar S, Shah Tuglak Khan F, Guchhait T, Rath SP. Binuclear complexes with single M-F-M bridge (M: Fe, Mn, and Cu): A critical analysis of the impact of fluoride for isoelectronic hydroxide substitution. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2022.215003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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8
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Misawa-Suzuki T, Nagao H. Ru(IV)-Ru(IV) complexes having the doubly oxido-bridged core with a bridging carbonato or hydrogencarbonato ligand. Dalton Trans 2023; 52:2863-2871. [PMID: 36762568 DOI: 10.1039/d2dt04080h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Ru(IV)-Ru(IV) complexes having the doubly oxido-bridged diamond core with a bridging carbonato or hydrogencarbonato ligand, [{RuIV(ebpma)}2(μ-O)2(μ-O2CO(H)m)]Xn (ebpma; ethylbis(2-pyridylmethyl)amine, m = 0; [IV,IV]X2 (X = PF6, ClO4), m = 1; [IV,IV_1H](ClO4)3), were isolated via the oxidation of the corresponding carbonato-bridged Ru(III)-Ru(IV) complex ([III,IV]+), and "[IV,IV](ClO4)2 and [IV,IV_1H](ClO4)3" were structurally characterized. The electrochemical and spectroscopic properties of [IV,IV]2+ and [IV,IV_1H]3+ were investigated both in organic solvents and aqueous solutions. The reactivity toward organic solvents having (a) methyl group(s) and reactions with organic substrates were studied as well. This should be the first time when systematic comparisons of the Ru(IV)-Ru(IV) species and corresponding Ru(III)-Ru(IV) complexes in the same tridentate ligand system were made.
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Affiliation(s)
- Tomoyo Misawa-Suzuki
- Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, 7-1 Kioicho Chiyoda-ku, Tokyo 102-8554, Japan.
| | - Hirotaka Nagao
- Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, 7-1 Kioicho Chiyoda-ku, Tokyo 102-8554, Japan.
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9
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Underhill J, Yang ES, Schmidt-Räntsch T, Myers WK, Goicoechea JM, Abbenseth J. Dioxygen Splitting by a Tantalum(V) Complex Ligated by a Rigid, Redox Non-Innocent Pincer Ligand. Chemistry 2023; 29:e202203266. [PMID: 36281622 PMCID: PMC10098518 DOI: 10.1002/chem.202203266] [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: 10/19/2022] [Indexed: 12/05/2022]
Abstract
The reaction of TaMe3 Cl2 with the rigid acridane-derived trisamine H3 NNN yields the tantalum(V) complex [TaCl2 (NNNcat )]. Subsequent reaction with dioxygen results in the full four-electron reduction of O2 yielding the oxido-bridged bimetallic complex [{TaCl2 (NNNsq )}2 O]. This dinuclear complex features an open-shell ground state due to partial ligand oxidation and was comprehensively characterized by single crystal X-ray diffraction, LIFDI mass spectrometry, NMR, EPR, IR and UV/VIS/NIR spectroscopy. The mechanism of O2 activation was investigated by DFT calculations revealing initial binding of O2 to the tantalum(V) center followed by complete O2 scission to produce a terminal oxido-complex.
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Affiliation(s)
- Jack Underhill
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Rd., Oxford, OX1 3TA, United Kingdom
| | - Eric S Yang
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Rd., Oxford, OX1 3TA, United Kingdom
| | - Till Schmidt-Räntsch
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstraße 4, 37077, Göttingen, Germany
| | - William K Myers
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Rd., Oxford, OX1 3TA, United Kingdom
| | - Jose M Goicoechea
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Rd., Oxford, OX1 3TA, United Kingdom
| | - Josh Abbenseth
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Rd., Oxford, OX1 3TA, United Kingdom
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10
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Jeong S, Lee K, Yoo SH, Lee HS, Kwon S. Crystalline Metal-Peptide Networks: Structures, Applications, and Future Outlook. Chembiochem 2023; 24:e202200448. [PMID: 36161687 DOI: 10.1002/cbic.202200448] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 09/23/2022] [Indexed: 01/20/2023]
Abstract
Metal-peptide networks (MPNs), which are assembled from short peptides and metal ions, are considered one of the most fascinating metal-organic coordinated architectures because of their unique and complicated structures. Although MPNs have considerable potential for development into versatile materials, they have not been developed for practical applications because of several underlying limitations, such as designability, stability, and modifiability. In this review, we summarise several important milestones in the development of crystalline MPNs and thoroughly analyse their structural features, such as peptide sequence designs, coordination geometries, cross-linking types, and network topologies. In addition, potential applications such as gas adsorption, guest encapsulation, and chiral recognition are introduced. We believe that this review is a useful survey that can provide insights into the development of new MPNs with more sophisticated structures and novel functions.
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Affiliation(s)
- Seoneun Jeong
- Center for Multiscale Chiral Architectures, Department of Chemistry, KAIST 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Korea
| | - Kwonjung Lee
- Department of Chemistry, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul, 06974, Korea
| | - Sung Hyun Yoo
- Department of Chemistry, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Korea
| | - Hee-Seung Lee
- Center for Multiscale Chiral Architectures, Department of Chemistry, KAIST 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Korea
| | - Sunbum Kwon
- Department of Chemistry, Chung-Ang University, 84 Heukseok-ro, Dongjak-gu, Seoul, 06974, Korea
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11
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Tan C, Tinnermann H, Wee V, Tan S, Sung S, Wang Q, Young RD. Synthesis of bimetallic rhodium phosphinine complexes with enhanced catalytic activity towards alkyne hydrosilylation. J Organomet Chem 2023. [DOI: 10.1016/j.jorganchem.2023.122617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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12
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Kumar P, Devkota L, Casey MC, Fischer AA, Lindeman SV, Fiedler AT. Reversible Dioxygen Binding to Co(II) Complexes with Noninnocent Ligands. Inorg Chem 2022; 61:16664-16677. [PMID: 36206536 PMCID: PMC11218047 DOI: 10.1021/acs.inorgchem.2c02246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A series of mononuclear Co(II) complexes with noninnocent (redox-active) ligands are prepared that exhibit metal-ligand cooperativity during the reversible binding of O2. The complexes have the general formula, [CoII(LS,N)(TpR2)] (R = Me, Ph), where LS,N is a bidentate o-aminothiophenolate and TpR2 is a hydrotris(pyrazol-1-yl)borate scorpionate with R-substituents at the 3- and 5-positions. Exposure to O2 at room temperature results in one-electron oxidation and deprotonation of LS,N. The oxidized derivatives possess substantial "singlet diradical" character arising from antiferromagnetic coupling between an iminothiosemiquinonate (ITSQ•-) ligand radical and a low-spin Co(II) ion. The [CoII(TpMe2)(X2ITSQ)] complexes, where X = H or tBu, coordinate O2 reversibly at reduced temperatures to provide Co/O2 adducts. The O2 binding reactions closely resemble those previously reported by our group (Kumar et al., J. Am. Chem. Soc. 2019,141, 10984-10987) for the related complexes [CoII(TpMe2)(tBu2SQ)] and [CoII(TpMe2)(tBu2ISQ)], where tBu2(I)SQ represents 4,6-di-tert-butyl-(2-imino)semiquinonate radicals. In each case, the oxygenation reaction proceeds via the addition of O2 to both the cobalt ion and the ligand radical, generating metallocyclic cobalt(III)-alkylperoxo structures. Thermodynamic measurements elucidate the relationship between O2 affinity and redox potentials of the (imino)(thio)semiquinonate radicals, as well as energetic differences between these reactions and conventional metal-based oxygenations. The results highlight the utility and versatility of noninnocent ligands in the design of O2-absorbing compounds.
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Affiliation(s)
- Praveen Kumar
- Department of Chemistry, Marquette University, 1414 W. Clybourn Street, Milwaukee, Wisconsin53233, United States
| | - Laxmi Devkota
- Department of Chemistry, Marquette University, 1414 W. Clybourn Street, Milwaukee, Wisconsin53233, United States
| | - Maximilian C Casey
- Department of Chemistry, Marquette University, 1414 W. Clybourn Street, Milwaukee, Wisconsin53233, United States
| | - Anne A Fischer
- Department of Chemistry, Marquette University, 1414 W. Clybourn Street, Milwaukee, Wisconsin53233, United States
| | - Sergey V Lindeman
- Department of Chemistry, Marquette University, 1414 W. Clybourn Street, Milwaukee, Wisconsin53233, United States
| | - Adam T Fiedler
- Department of Chemistry, Marquette University, 1414 W. Clybourn Street, Milwaukee, Wisconsin53233, United States
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13
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Yadav O, Ansari M, Ansari A. Electronic structures, bonding aspects and spectroscopic parameters of homo/hetero valent bridged dinuclear transition metal complexes. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 278:121331. [PMID: 35597159 DOI: 10.1016/j.saa.2022.121331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/25/2022] [Accepted: 04/27/2022] [Indexed: 06/15/2023]
Abstract
Bridged dinuclear metal complexes have fascinated scientists worldwide, and remarkable success has been achieved to unravel the electronic structures, structure-function relationship, coordination environments, and fine mechanistic details of the enzymes owing to the repercussion of biomimetic studies carried out on dinuclear model systems. Molecular level study of these systems integrated with spectroscopic study helps in gaining deep insights about structural and electronic aspects of natural enzymatic systems. Considering the same, here first time we report DFT study on bridged non-heme metal complexes based on N-Et-HPTB ligand system containing homovalent (MIIMII); {[(MnII)2(O2CCH3)(N-Et-HPTB)]2+; Species I), [(FeII)2(O2CCH3)(N-Et-HPTB)]2+; Species II), [(CoII)2(O2CCH3)(N-Et-HPTB)]2+; Species III)} and heterovalent (MIIIMII): {[(MnIII)(MnII)(O2)(N-Et-HPTB)]2+; Species Ia) [(FeIII)(FeII)(O2)(N-Et-HPTB)]2+; Species IIa) and [(CoIII)(CoII)(O2)(N-Et-HPTB)]2+; Species IIIa)} dinuclear metal centres. Bridging oxygen bears a significant spin density which may prompt important chemical reactions involving activation of bonds like C-H/O-H/N-H etc. TD-DFT calculations for UV-Visible absorption have been carried out to further shed light on structural-functional and electronic structures of these dinuclear species. Studying these dinuclear species may be a good starting point for the study of active sites of the bimetallic centre of dinuclear enzymes and thus may serve as fascinating spectroscopic models. Further, FMO analysis, MEP mapping, and NBO calculations were employed to analyze bonding aspects predict theoretical reactivity behaviour and any kind of stabilizing interactions present in the reported species.
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Affiliation(s)
- Oval Yadav
- Department of Chemistry, Central University of Haryana, Mahendergarh 123031, India
| | - Mursaleem Ansari
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, Pawai 400076, India
| | - Azaj Ansari
- Department of Chemistry, Central University of Haryana, Mahendergarh 123031, India.
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14
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Van Stappen C, Deng Y, Liu Y, Heidari H, Wang JX, Zhou Y, Ledray AP, Lu Y. Designing Artificial Metalloenzymes by Tuning of the Environment beyond the Primary Coordination Sphere. Chem Rev 2022; 122:11974-12045. [PMID: 35816578 DOI: 10.1021/acs.chemrev.2c00106] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Metalloenzymes catalyze a variety of reactions using a limited number of natural amino acids and metallocofactors. Therefore, the environment beyond the primary coordination sphere must play an important role in both conferring and tuning their phenomenal catalytic properties, enabling active sites with otherwise similar primary coordination environments to perform a diverse array of biological functions. However, since the interactions beyond the primary coordination sphere are numerous and weak, it has been difficult to pinpoint structural features responsible for the tuning of activities of native enzymes. Designing artificial metalloenzymes (ArMs) offers an excellent basis to elucidate the roles of these interactions and to further develop practical biological catalysts. In this review, we highlight how the secondary coordination spheres of ArMs influence metal binding and catalysis, with particular focus on the use of native protein scaffolds as templates for the design of ArMs by either rational design aided by computational modeling, directed evolution, or a combination of both approaches. In describing successes in designing heme, nonheme Fe, and Cu metalloenzymes, heteronuclear metalloenzymes containing heme, and those ArMs containing other metal centers (including those with non-native metal ions and metallocofactors), we have summarized insights gained on how careful controls of the interactions in the secondary coordination sphere, including hydrophobic and hydrogen bonding interactions, allow the generation and tuning of these respective systems to approach, rival, and, in a few cases, exceed those of native enzymes. We have also provided an outlook on the remaining challenges in the field and future directions that will allow for a deeper understanding of the secondary coordination sphere a deeper understanding of the secondary coordintion sphere to be gained, and in turn to guide the design of a broader and more efficient variety of ArMs.
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Affiliation(s)
- Casey Van Stappen
- Department of Chemistry, University of Texas at Austin, 105 East 24th Street, Austin, Texas 78712, United States
| | - Yunling Deng
- Department of Chemistry, University of Texas at Austin, 105 East 24th Street, Austin, Texas 78712, United States
| | - Yiwei Liu
- Department of Chemistry, University of Illinois, Urbana-Champaign, 505 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Hirbod Heidari
- Department of Chemistry, University of Texas at Austin, 105 East 24th Street, Austin, Texas 78712, United States
| | - Jing-Xiang Wang
- Department of Chemistry, University of Texas at Austin, 105 East 24th Street, Austin, Texas 78712, United States
| | - Yu Zhou
- Department of Chemistry, University of Texas at Austin, 105 East 24th Street, Austin, Texas 78712, United States
| | - Aaron P Ledray
- Department of Chemistry, University of Texas at Austin, 105 East 24th Street, Austin, Texas 78712, United States
| | - Yi Lu
- Department of Chemistry, University of Texas at Austin, 105 East 24th Street, Austin, Texas 78712, United States.,Department of Chemistry, University of Illinois, Urbana-Champaign, 505 South Mathews Avenue, Urbana, Illinois 61801, United States
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15
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Kejriwal A. Non-heme iron coordination complexes for alkane oxidation using hydrogen peroxide (H 2O 2) as powerful oxidant. J COORD CHEM 2022. [DOI: 10.1080/00958972.2022.2085567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Ambica Kejriwal
- Department of Chemistry, Raiganj University, Raiganj, West Bengal, India
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16
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Guan H, Tung CH, Liu L. Methane Monooxygenase Mimic Asymmetric Oxidation: Self-Assembling μ-Hydroxo, Carboxylate-Bridged Diiron(III)-Catalyzed Enantioselective Dehydrogenation. J Am Chem Soc 2022; 144:5976-5984. [PMID: 35324200 DOI: 10.1021/jacs.2c00638] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Mimicking naturally occurring metalloenzymes to enrich the diversity of catalytic asymmetric oxidation reactions is a long-standing goal for modern chemistry. Toward this end, a range of methane monooxygenase (MMO) mimic chiral carboxylate-bridged (μ-hydroxo) diiron(III) dimer complexes using salan as basal ligand and sodium aryl carboxylate as additive have been designed and synthesized. The chiral diiron complexes exhibit efficient catalytic reactivity in dehydrogenative kinetic resolution of indolines using environmentally benign hydrogen peroxide as oxidant. In particular, complex C9 bearing sterically encumbered salan ligands and a 2-naphthoate bridge is identified as the optimal catalyst in terms of chiral recognition. Further investigation reveals that this MMO mimic chiral catalyst can be readily generated by self-assembly under the dehydrogenation conditions. The self-assembling catalytic system is applicable to a series of indolines with multiple stereocenters and diverse substituent patterns in high efficiency with a high level of chiral recognition (selectivity factor up to 153). Late-stage dehydrogenative kinetic resolution of bioactive molecules is further examined.
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Affiliation(s)
- Honghao Guan
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Chen-Ho Tung
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Lei Liu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
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17
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Lee JL, Biswas S, Sun C, Ziller JW, Hendrich MP, Borovik AS. Bioinspired Di-Fe Complexes: Correlating Structure and Proton Transfer over Four Oxidation States. J Am Chem Soc 2022; 144:4559-4571. [PMID: 35192354 DOI: 10.1021/jacs.1c12888] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Metalloproteins with active sites containing di-Fe cores exhibit diverse chemical reactivity that is linked to the precise transfer of protons and electrons which directly involve the di-Fe units. The redox conversions are commonly corroborated by spectroscopic methods, but the associated structural changes are often difficult to assess, particularly those related to proton movements. This report describes the development of di-Fe complexes in which the movements of protons and electrons are pinpointed during the stepwise oxidation of a di-FeII species to one with an FeIIIFeIV core. Complex formation was promoted using the phosphinic amido tripodal ligand [poat]3- (N,N',N″-[nitrilotris(ethane-2,1-diyl)]tris(P,P-diphenylphosphinic amido)) that provided dynamic coordination spheres that assisted in regulating both electron and proton transfer processes. Oxidation of an [FeII-(μ-OH)-FeIII] complex led to the corresponding di-FeIII species containing a hydroxido bridge that was not stable at room temperature and converted to a species containing an oxido bridging ligand and protonation of one phosphinic amido group to form [Hpoat]2-. Deprotonation led to a new species with an [FeIII-(μ-O)-FeIII] core that could be further oxidized to its FeIIIFeIV analogue. Reactions with phenols suggest homolytic cleavage of the O-H bond to give products that are consistent with the initial formation of a phenoxyl radical─spectroscopic studies indicated that the electron is transferred to the FeIV center, and the proton is initially transferred to the more sterically hindered oxido ligand but then relocates to [poat]3-. These findings offer new mechanistic insights related to the stability of and the reactions performed by di-Fe enzymes.
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Affiliation(s)
- Justin L Lee
- Department of Chemistry, University of California,1102 Natural Sciences II, Irvine, California 92697, United States
| | - Saborni Biswas
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Chen Sun
- Department of Chemistry, University of California,1102 Natural Sciences II, Irvine, California 92697, United States
| | - Joseph W Ziller
- Department of Chemistry, University of California,1102 Natural Sciences II, Irvine, California 92697, United States
| | - Michael P Hendrich
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - A S Borovik
- Department of Chemistry, University of California,1102 Natural Sciences II, Irvine, California 92697, United States
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18
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Lee Y, Oh C, Kim J, Park MS, Bae WK, Yoo KH, Hong S. Bioinspired nonheme iron complex that triggers mitochondrial apoptotic signalling pathway specifically for colorectal cancer cells. Chem Sci 2022; 13:737-747. [PMID: 35173938 PMCID: PMC8768841 DOI: 10.1039/d1sc05094j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 12/10/2021] [Indexed: 12/24/2022] Open
Abstract
The activation of dioxygen is the keystone of all forms of aerobic life. Many biological functions rely on the redox versatility of metal ions to perform reductive activation-mediated processes entailing dioxygen and its partially reduced species including superoxide, hydrogen peroxide, and hydroxyl radicals, also known as reactive oxygen species (ROS). In biomimetic chemistry, a number of synthetic approaches have sought to design, synthesize and characterize reactive intermediates such as the metal-superoxo, -peroxo, and -oxo species, which are commonly found as key intermediates in the enzymatic catalytic cycle. However, the use of these designed complexes and their corresponding intermediates as potential candidates for cancer therapeutics has scarcely been endeavored. In this context, a series of biomimetic first-row transition metal complexes bearing a picolylamine-based water-soluble ligand, [M(HN3O2)]2+ (M = Mn2+, Fe2+, Co2+, Cu2+; HN3O2 = 2-(2-(bis(pyridin-2-ylmethyl)amino)ethoxy)ethanol) were synthesized and characterized by various spectroscopic methods including X-ray crystallography and their dioxygen and ROS activation reactivity were evaluated in situ and in vitro. It turned out that among these metal complexes, the iron complex, [Fe(HN3O2)(H2O)]2+, was capable of activating dioxygen and hydrogen peroxide and produced the ROS species (e.g., hydroxyl radical). Upon the incubation of these complexes with different cancer cells, such as cervical, breast, and colorectal cancer cells (MDA-MB-231, AU565, SK-BR-3, HeLa S3, HT-29, and HCT116 cells), only the iron complex triggered cellular apoptosis specifically for colorectal cancer cells; the other metal complexes show negligible anti-proliferative activity. More importantly, the biomimetic complexes were harmless to normal cells and produced less ROS therein. The use of immunocytochemistry combined with western blot analysis strongly supported that apoptosis occurred via the intrinsic mitochondrial pathway; in the intracellular network, [Fe(HN3O2)(H2O)]2+ resulted in (i) the activation and/or production of ROS species, (ii) the induction of intracellular impaired redox balance, and (iii) the promotion of the mitochondrial apoptotic signaling pathway in colorectal cancer cells. The results have implications for developing novel biomimetic complexes in cancer treatments and for designing potent candidates with cancer-specific antitumor activity. A water-soluble iron complex that produces hydroxyl radical species triggers colorectal cancer cell death via the mitochondrial apoptotic pathway.![]()
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Affiliation(s)
- Yool Lee
- Department of Chemistry, Sookmyung Women's University Seoul 04310 Korea
| | - Chaeun Oh
- Department of Biological Sciences, Sookmyung Women's University Seoul 04310 Korea
| | - Jin Kim
- Department of Chemistry, Sunchon National University Suncheon 57922 Korea
| | - Myong-Suk Park
- Division of Hemato-Oncology, Department of Internal Medicine, Chonnam National University Medical School and Hwasun Hospital Hwasun Republic of Korea
| | - Woo Kyun Bae
- Division of Hemato-Oncology, Department of Internal Medicine, Chonnam National University Medical School and Hwasun Hospital Hwasun Republic of Korea .,Combinatorial Tumor Immunotherapy MRC Center, Chonnam National University Medical School Hwasun Republic of Korea
| | - Kyung Hyun Yoo
- Department of Biological Sciences, Sookmyung Women's University Seoul 04310 Korea
| | - Seungwoo Hong
- Department of Chemistry, Sookmyung Women's University Seoul 04310 Korea
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19
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Liu Y, Gu X, Jiang W, Li H, Ma Y, Liu C, Wu Y, Che G. In Situ Synthesis of Morphology-Controlled MoOx/Fe1-xS Bifunctional Catalysts for High-Efficiency and Stable Alkaline Water Splitting. Dalton Trans 2022; 51:9486-9494. [DOI: 10.1039/d2dt01098d] [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 advancement of a bifunctional electrocatalyst consisting of earth's rich elements and with high efficiency is the key to obtain hydrogen fuel by overall water splitting (OWS). Here, a facile...
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20
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Ciambellotti S, Pratesi A, Tassone G, Turano P, Mangani S, Pozzi C. Iron Binding in the Ferroxidase Site of Human Mitochondrial Ferritin. Chemistry 2021; 27:14690-14701. [PMID: 34343376 DOI: 10.1002/chem.202102270] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Indexed: 12/12/2022]
Abstract
Ferritins are nanocage proteins that store iron ions in their central cavity as hydrated ferric oxide biominerals. In mammals, further the L (light) and H (heavy) chains constituting cytoplasmic maxi-ferritins, an additional type of ferritin has been identified, the mitochondrial ferritin (MTF). Human MTF (hMTF) is a functional homopolymeric H-like ferritin performing the ferroxidase activity in its ferroxidase site (FS), in which Fe(II) is oxidized to Fe(III) in the presence of dioxygen. To better investigate its ferroxidase properties, here we performed time-lapse X-ray crystallography analysis of hMTF, providing structural evidence of how iron ions interact with hMTF and of their binding to the FS. Transient iron binding sites, populating the pathway along the cage from the iron entry channel to the catalytic center, were also identified. Furthermore, our kinetic data at variable iron loads indicate that the catalytic iron oxidation reaction occurs via a diferric peroxo intermediate followed by the formation of ferric-oxo species, with significant differences with respect to human H-type ferritin.
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Affiliation(s)
- Silvia Ciambellotti
- Department of Chemistry "Ugo Schiff" Department of Excellence 2018-2022, University of Florence, via della Lastruccia 2, 50019, Sesto Fiorentino, Italy.,Magnetic Resonance Center (CERM), University of Florence, Luigi Sacconi 6, 50019, Sesto Fiorentino (FI), Italy.,Consorzio Interuniversitario Risonanze Magnetiche di, Metallo Proteine (C.I.R.M.M.P.), via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy
| | - Alessandro Pratesi
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via Giuseppe Moruzzi 13, 56124, Pisa, Italy
| | - Giusy Tassone
- Department of Biotechnology, Chemistry and Pharmacy Department of Excellence 2018-2020, University of Siena, via Aldo Moro, 2, 53110, Siena, Italy
| | - Paola Turano
- Department of Chemistry "Ugo Schiff" Department of Excellence 2018-2022, University of Florence, via della Lastruccia 2, 50019, Sesto Fiorentino, Italy.,Magnetic Resonance Center (CERM), University of Florence, Luigi Sacconi 6, 50019, Sesto Fiorentino (FI), Italy.,Consorzio Interuniversitario Risonanze Magnetiche di, Metallo Proteine (C.I.R.M.M.P.), via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy
| | - Stefano Mangani
- Magnetic Resonance Center (CERM), University of Florence, Luigi Sacconi 6, 50019, Sesto Fiorentino (FI), Italy.,Consorzio Interuniversitario Risonanze Magnetiche di, Metallo Proteine (C.I.R.M.M.P.), via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy.,Department of Biotechnology, Chemistry and Pharmacy Department of Excellence 2018-2020, University of Siena, via Aldo Moro, 2, 53110, Siena, Italy
| | - Cecilia Pozzi
- Department of Biotechnology, Chemistry and Pharmacy Department of Excellence 2018-2020, University of Siena, via Aldo Moro, 2, 53110, Siena, Italy
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21
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DeLucia AA, Kelly KA, Herrera KA, Gray DL, Olshansky L. Intramolecular Hydrogen-Bond Interactions Tune Reactivity in Biomimetic Bis(μ-hydroxo)dicobalt Complexes. Inorg Chem 2021; 60:15599-15609. [PMID: 34606250 DOI: 10.1021/acs.inorgchem.1c02210] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Active site hydrogen-bond (H-bond) networks represent a key component by which metalloenzymes control the formation and deployment of high-valent transition metal-oxo intermediates. We report a series of dinuclear cobalt complexes that serve as structural models for the nonheme diiron enzyme family and feature a Co2(μ-OH)2 diamond core stabilized by intramolecular H-bond interactions. We define the conditions required for the kinetically controlled synthesis of these complexes: [Co2(μ-OH)2(μ-OAc)(κ1-OAc)2(pyR)4][PF6] (1R), where OAc = acetate and pyR = pyridine with para-substituent R, and we describe a homologous series of 1R in which the para-R substituent on pyridine is modulated. The solid state X-ray diffraction (XRD) structures of 1R are similar across the series, but in solution, their 1H NMR spectra reveal a linear free energy relationship (LFER) where, as R becomes increasingly electron-withdrawing, the intramolecular H-bond interaction between bridging μ-OH and κ1-acetate ligands results in increasingly "oxo-like" μ-OH bridges. Deprotonation of the bridging μ-OH results in the quantitative conversion to corresponding cubane complexes: [Co4(μ-O)4(μ3-OAc)4(pyR)4] (2R), which represent the thermodynamic sink of self-assembly. These reactions are unusually slow for rate-limiting deprotonation events, but rapid-mixing experiments reveal a 6000-fold rate acceleration on going from R = OMe to R = CN. These results suggest that we can tune reactivity by modulating the μ-OH pKa in the presence of intramolecular H-bond interactions to maintain stability as the octahedral d6 centers become increasingly acidic. Nature may similarly employ dynamic carboxylate-mediated H-bond interactions to control the reactivity of acidic transition metal-oxo intermediates.
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Affiliation(s)
- Alyssa A DeLucia
- Department of Chemistry, University of Illinois, Urbana-Champaign, 600 S. Mathews Ave. Urbana, Illinois 61801, United States
| | - Kimberly A Kelly
- Department of Chemistry, University of Illinois, Urbana-Champaign, 600 S. Mathews Ave. Urbana, Illinois 61801, United States
| | - Kevin A Herrera
- Department of Chemistry, University of Illinois, Urbana-Champaign, 600 S. Mathews Ave. Urbana, Illinois 61801, United States
| | - Danielle L Gray
- Department of Chemistry, University of Illinois, Urbana-Champaign, 600 S. Mathews Ave. Urbana, Illinois 61801, United States
| | - Lisa Olshansky
- Department of Chemistry, University of Illinois, Urbana-Champaign, 600 S. Mathews Ave. Urbana, Illinois 61801, United States
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22
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Mukherjee M, Dey A. Rejigging Electron and Proton Transfer to Transition between Dioxygenase, Monooxygenase, Peroxygenase, and Oxygen Reduction Activity: Insights from Bioinspired Constructs of Heme Enzymes. JACS AU 2021; 1:1296-1311. [PMID: 34604840 PMCID: PMC8479764 DOI: 10.1021/jacsau.1c00100] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Indexed: 05/10/2023]
Abstract
Nature has employed heme proteins to execute a diverse set of vital life processes. Years of research have been devoted to understanding the factors which bias these heme enzymes, with all having a heme cofactor, toward distinct catalytic activity. Among them, axial ligation, distal super structure, and substrate binding pockets are few very vividly recognized ones. Detailed mechanistic investigation of these heme enzymes suggested that several of these enzymes, while functionally divergent, use similar intermediates. Furthermore, the formation and decay of these intermediates depend on proton and electron transfer processes in the enzyme active site. Over the past decade, work in this group, using in situ surface enhanced resonance Raman spectroscopy of synthetic and biosynthetic analogues of heme enzymes, a general idea of how proton and electron transfer rates relate to the lifetime of different O2 derived intermediates has been developed. These findings suggest that the enzymatic activities of all these heme enzymes can be integrated into one general cycle which can be branched out to different catalytic pathways by regulating the lifetime and population of each of these intermediates. This regulation can further be achieved by tuning the electron and proton transfer steps. By strategically populating one of these intermediates during oxygen reduction, one can navigate through different catalytic processes to a desired direction by altering proton and electron transfer steps.
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Affiliation(s)
- Manjistha Mukherjee
- School of Chemical Science, Indian Association for the Cultivation of Science, 2A Raja SC Mullick Road, Kolkata, WB India, 700032
| | - Abhishek Dey
- School of Chemical Science, Indian Association for the Cultivation of Science, 2A Raja SC Mullick Road, Kolkata, WB India, 700032
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23
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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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24
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Geary J, Wong AH, Xiao DJ. Thermolabile Cross-Linkers for Templating Precise Multicomponent Metal-Organic Framework Pores. J Am Chem Soc 2021; 143:10317-10323. [PMID: 34184884 DOI: 10.1021/jacs.1c04030] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
While a number of approaches toward multicomponent metal-organic frameworks have been reported, new strategies affording greater structural versatility and molecular precision are needed to replicate the sophisticated active sites found in enzymes. Here, we outline a general method for templating functional groups within framework pores using thermolabile ligand cross-linkers. We show that tertiary ester-based cross-linkers can be used to install well-defined carboxylic acid pairs at precise relative distances and orientations. The tertiary ester linkages remain intact during framework formation but are readily cleaved to reveal free carboxylic acids upon microwave heating. Successful cross-linker synthesis, framework incorporation, and thermolysis is demonstrated using the mesoporous, terphenyl expanded analogues of MOF-74. When short cross-linkers are used, modeling studies show that the carboxylic acids are installed in a single configuration down the pore channels, spaced ∼7 Å apart. These precisely positioned acid pairs can be used as synthetic handles to build up more complex cooperative active sites.
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Affiliation(s)
- Jackson Geary
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Andy H Wong
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
| | - Dianne J Xiao
- Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, United States
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25
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Chandra A, Ansari M, Monte‐Pérez I, Kundu S, Rajaraman G, Ray K. Ligand‐Constraint‐Induced Peroxide Activation for Electrophilic Reactivity. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202100438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Anirban Chandra
- Department of Chemistry Humboldt-Universität zu Berlin Brook-Taylor-Strasse 2 12489 Berlin Germany
| | - Mursaleem Ansari
- Department of Chemistry Indian Institute of Technology Bombay, Powai Mumbai Maharashtra 400 076 India
| | - Inés Monte‐Pérez
- Department of Chemistry Humboldt-Universität zu Berlin Brook-Taylor-Strasse 2 12489 Berlin Germany
| | - Subrata Kundu
- Department of Chemistry Humboldt-Universität zu Berlin Brook-Taylor-Strasse 2 12489 Berlin Germany
| | - Gopalan Rajaraman
- Department of Chemistry Indian Institute of Technology Bombay, Powai Mumbai Maharashtra 400 076 India
| | - Kallol Ray
- Department of Chemistry Humboldt-Universität zu Berlin Brook-Taylor-Strasse 2 12489 Berlin Germany
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Chandra A, Ansari M, Monte-Pérez I, Kundu S, Rajaraman G, Ray K. Ligand-Constraint-Induced Peroxide Activation for Electrophilic Reactivity. Angew Chem Int Ed Engl 2021; 60:14954-14959. [PMID: 33843113 PMCID: PMC8252416 DOI: 10.1002/anie.202100438] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 03/26/2021] [Indexed: 12/16/2022]
Abstract
μ‐1,2‐peroxo‐bridged diiron(III) intermediates P are proposed as reactive intermediates in various biological oxidation reactions. In sMMO, P acts as an electrophile, and performs hydrogen atom and oxygen atom transfers to electron‐rich substrates. In cyanobacterial ADO, however, P is postulated to react by nucleophilic attack on electrophilic carbon atoms. In biomimetic studies, the ability of μ‐1,2‐peroxo‐bridged dimetal complexes of Fe, Co, Ni and Cu to act as nucleophiles that effect deformylation of aldehydes is documented. By performing reactivity and theoretical studies on an end‐on μ‐1,2‐peroxodicobalt(III) complex 1 involving a non‐heme ligand system, L1, supported on a Sn6O6 stannoxane core, we now show that a peroxo‐bridged dimetal complex can also be a reactive electrophile. The observed electrophilic chemistry, which is induced by the constraints provided by the Sn6O6 core, represents a new domain for metal−peroxide reactivity.
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Affiliation(s)
- Anirban Chandra
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489, Berlin, Germany
| | - Mursaleem Ansari
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, Maharashtra, 400 076, India
| | - Inés Monte-Pérez
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489, Berlin, Germany
| | - Subrata Kundu
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489, Berlin, Germany
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, Maharashtra, 400 076, India
| | - Kallol Ray
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489, Berlin, Germany
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27
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Balamurugan M, Suresh E, Palaniandavar M. μ-Oxo-bridged diiron(iii) complexes of tripodal 4N ligands as catalysts for alkane hydroxylation reaction using m-CPBA as an oxidant: substrate vs. self hydroxylation. RSC Adv 2021; 11:21514-21526. [PMID: 35478792 PMCID: PMC9034113 DOI: 10.1039/d1ra03135j] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 05/28/2021] [Indexed: 11/23/2022] Open
Abstract
A series of non-heme μ-oxo-bridged dinuclear iron(iii) complexes of the type [Fe2(μ-O)(L1–L6)2Cl2]Cl21–6 have been isolated and their catalytic activity towards oxidative transformation of alkanes into alcohols has been studied using m-choloroperbenzoic acid (m-CPBA) as an oxidant. All the complexes were characterized by CHN, electrochemical, and UV-visible spectroscopic techniques. The molecular structures of 2 and 5 have been determined successfully by single crystal X-ray diffraction analysis and both possesses octahedral coordination geometry and each iron atom is coordinated by four nitrogen atoms of the 4N ligand and a bridging oxygen. The sixth position of each octahedron is coordinated by a chloride ion. The (μ-oxo)diiron(iii) core is linear in 2 (Fe–O–Fe, 180.0°), whereas it is non-linear (Fe–O–Fe, 161°) in 5. All the diiron(iii) complexes show quasi-reversible one electron transfer in the cyclic voltammagram and catalyze the hydroxylation of alkanes like cyclohexane, adamantane with m-CPBA as an oxidant. In acetonitrile solution, adding excess m-CPBA to the diiron(iii) complex 2 without chloride ions leads to intramolecular hydroxylation reaction of the oxidant. Interestingly, 2 catalyzes alkane hydroxylation in the presence of chloride ions, but intramolecular hydroxylation in the absence of chloride ions. The observed selectivity for cyclohexane (A/K, 5–7) and adamantane (3°/2°, 9–18) suggests the involvement of high-valent iron–oxo species rather than freely diffusing radicals in the catalytic reaction. Moreover, 4 oxidizes (A/K, 7) cyclohexane very efficiently up to 513 TON while 5 oxidizes adamantane with good selectivity (3°/2°, 18) using m-CPBA as an oxidant. The electronic effects of ligand donors dictate the efficiency and selectivity of catalytic hydroxylation of alkanes. The ligand stereoelectronic effect of diiron(iii) complexes determines the efficiency and selectivity of catalytic alkane hydroxylation with m-CPBA as an oxidant.![]()
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Affiliation(s)
- Mani Balamurugan
- School of Chemistry, Bharathidasan University Tiruchirappalli 620 024 Tamil Nadu India
| | - Eringathodi Suresh
- Analytical Science Discipline, Central Salt and Marine Chemicals Research Institute Bhavnagar 364 002 India
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28
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Yamada Y, Kura J, Toyoda Y, Tanaka K. High catalytic methane oxidation activity of monocationic μ-nitrido-bridged iron phthalocyanine dimer with sixteen methyl groups. Dalton Trans 2021; 50:6718-6724. [PMID: 33908999 DOI: 10.1039/d1dt00941a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Herein, we report the highly potent catalytic methane oxidation activity of a monocationic μ-nitrido-bridged iron phthalocyanine dimer with 16 peripheral methyl groups. It was confirmed that this complex oxidized methane stably into MeOH, HCHO, and HCOOH in a catalytic manner in an acidic aqueous solution containing excess H2O2 at 60 °C. The total turnover number of the reaction reached 135 after 12 h, which is almost seven times higher than that of a monocatinoic μ-nitrido-bridged iron phthalocyanine dimer with no peripheral substituents. This suggests that the increased number of peripheral electron-donating substituents could have facilitated the generation of a reactive high-valent iron-oxo species as well as hydrogen abstraction from methane by the reactive iron-oxo species.
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Affiliation(s)
- Yasuyuki Yamada
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan. and Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan and JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Jyunichi Kura
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
| | - Yuka Toyoda
- Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Kentaro Tanaka
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
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29
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Schulz CE, Castillo RG, Pantazis DA, DeBeer S, Neese F. Structure-Spectroscopy Correlations for Intermediate Q of Soluble Methane Monooxygenase: Insights from QM/MM Calculations. J Am Chem Soc 2021; 143:6560-6577. [PMID: 33884874 PMCID: PMC8154522 DOI: 10.1021/jacs.1c01180] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
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The determination
of the diiron core intermediate structures involved
in the catalytic cycle of soluble methane monooxygenase (sMMO), the
enzyme that selectively catalyzes the conversion of methane to methanol,
has been a subject of intense interest within the bioinorganic scientific
community. Particularly, the specific geometry and electronic structure
of the intermediate that precedes methane binding, known as intermediate
Q (or MMOHQ), has been debated for over 30 years. Some
reported studies support a bis-μ-oxo-bridged Fe(IV)2O2 closed-core conformation Fe(IV)2O2 core, whereas others favor an open-core geometry, with a longer
Fe–Fe distance. The lack of consensus calls for a thorough
re-examination and reinterpretation of the spectroscopic data available
on the MMOHQ intermediate. Herein, we report extensive
simulations based on a hybrid quantum mechanics/molecular mechanics
approach (QM/MM) approach that takes into account the complete enzyme
to explore possible conformations for intermediates MMOHox and MMOHQ of the sMMOH catalytic cycle. High-level quantum
chemical approaches are used to correlate specific structural motifs
with geometric parameters for comparison with crystallographic and
EXAFS data, as well as with spectroscopic data from Mössbauer
spectroscopy, Fe K-edge high-energy resolution X-ray absorption spectroscopy
(HERFD XAS), and resonance Raman 16O–18O difference spectroscopy. The results provide strong support for
an open-core-type configuration in MMOHQ, with the most
likely topology involving mono-oxo-bridged Fe ions and alternate terminal
Fe-oxo and Fe-hydroxo groups that interact via intramolecular hydrogen
bonding. The implications of an open-core intermediate Q on the reaction
mechanism of sMMO are discussed.
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Affiliation(s)
- Christine E Schulz
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Rebeca G Castillo
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Dimitrios A Pantazis
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Frank Neese
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
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30
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Suzuki T, Sato A, Oshita H, Yajima T, Tani F, Abe H, Mieda-Higa K, Yanagisawa S, Ogura T, Shimazaki Y. Formation of Ni(II)-phenoxyl radical complexes by O 2: a mechanistic insight into the reaction of Ni(II)-phenol complexes with O 2. Dalton Trans 2021; 50:5161-5170. [PMID: 33881085 DOI: 10.1039/d1dt00105a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A reaction of Ni(ClO4)2·6H2O with a tripodal ligand having two di(tert-butyl)phenol moieties, H2tbuL, and 1 equivalent of triethylamine in CH2Cl2/CH3OH (1 : 1, v/v) under N2 gave a NiII-(phenol)(phenolate) complex, [Ni(HtbuL)(CH3OH)2]ClO4. The formation of the NiII-phenoxyl radical complex by O2 was observed in the reaction of this complex in the solid state. On the other hand, the NiII-phenoxyl radical complex [Ni(Me2NL)(CH3OH)2]ClO4 was obtained by the reaction of H2Me2NL having a p-(dimethylamino)phenol moiety with Ni(ClO4)2·6H2O in a similar procedure under O2, through the oxidation of the NiII-(phenol)(phenolate) complex. However, a direct redox reaction of the NiII ion could not be detected in the phenoxyl radical formation. The results of the reaction kinetics, XAS and X-ray structure analyses suggested that the O2 oxidation from the NiII-(phenol)(phenolate) complex to the NiII-phenoxyl radical complex occurs via the proton transfer-electron transfer (PT-ET) type mechanism of the phenol moiety weakly coordinated to the nickel ion.
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Affiliation(s)
- Takashi Suzuki
- Graduate School of Science and Engineering, Ibaraki University, Mito 310-8512, Japan.
| | - Akari Sato
- Graduate School of Science and Engineering, Ibaraki University, Mito 310-8512, Japan.
| | - Hiromi Oshita
- Faculty of Chemistry of Functional Molecules, Konan University, Higashinada-ku, Kobe 658-8501, Japan
| | - Tatsuo Yajima
- Faculty of Chemistry, Materials and Bioengineering, Kansai University, Suita, Osaka 564-8680, Japan
| | - Fumito Tani
- Institute for Materials Chemistry and Engineering, Kyushu University, Nishi-Ku, Fukuoka 819-0395, Japan
| | - Hitoshi Abe
- Graduate School of Science and Engineering, Ibaraki University, Mito 310-8512, Japan. and Institute of Materials Structure Science (IMSS), High Energy Accelerator Research Organization (KEK) 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan and Department of Materials Structure Science, School of High Energy Accelerator Science, SOKENDAI (the Graduate University for Advanced Studies), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Kaoru Mieda-Higa
- Graduate School of Life Science, University of Hyogo, Kamigori, Hyogo 678-1297, Japan
| | - Sachiko Yanagisawa
- Graduate School of Life Science, University of Hyogo, Kamigori, Hyogo 678-1297, Japan
| | - Takashi Ogura
- Graduate School of Life Science, University of Hyogo, Kamigori, Hyogo 678-1297, Japan
| | - Yuichi Shimazaki
- Graduate School of Science and Engineering, Ibaraki University, Mito 310-8512, Japan.
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31
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SHINDE N, HANDA R, FURUTACHI H, SAKATA Y, AKINE S, FUJINAMI S, SUZUKI M. Synthesis and Crystal Structure of (μ-Acetato)bis(μ-Alkoxo)dicobalt(II, III) Complex with an Unsymmetric Dinucleating Ligand. X-RAY STRUCTURE ANALYSIS ONLINE 2021. [DOI: 10.2116/xraystruct.37.13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Naho SHINDE
- Department of Chemistry, Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University
| | - Ryunosuke HANDA
- Department of Chemistry, Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University
| | - Hideki FURUTACHI
- Department of Chemistry, Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University
- WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University
| | - Yoko SAKATA
- Department of Chemistry, Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University
- WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University
| | - Shigehisa AKINE
- Department of Chemistry, Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University
- WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University
| | - Shuhei FUJINAMI
- Department of Chemistry, Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University
| | - Masatatsu SUZUKI
- Department of Chemistry, Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University
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32
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Kerbib W, Singh S, Nautiyal D, Kumar A, Kumar S. Ni(II) complexes of tripodal N4 ligands as catalysts for alkane hydroxylation and O-arylation of phenol: Structural and reactivity effects induced by fluoro substitution. Inorganica Chim Acta 2021. [DOI: 10.1016/j.ica.2020.120191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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33
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Miller KR, Biswas S, Jasniewski A, Follmer AH, Biswas A, Albert T, Sabuncu S, Bominaar EL, Hendrich MP, Moënne-Loccoz P, Borovik AS. Artificial Metalloproteins with Dinuclear Iron-Hydroxido Centers. J Am Chem Soc 2021; 143:2384-2393. [PMID: 33528256 DOI: 10.1021/jacs.0c12564] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Dinuclear iron centers with a bridging hydroxido or oxido ligand form active sites within a variety of metalloproteins. A key feature of these sites is the ability of the protein to control the structures around the Fe centers, which leads to entatic states that are essential for function. To simulate this controlled environment, artificial proteins have been engineered using biotin-streptavidin (Sav) technology in which Fe complexes from adjacent subunits can assemble to form [FeIII-(μ-OH)-FeIII] cores. The assembly process is promoted by the site-specific localization of the Fe complexes within a subunit through the designed mutation of a tyrosinate side chain to coordinate the Fe centers. An important outcome is that the Sav host can regulate the Fe···Fe separation, which is known to be important for function in natural metalloproteins. Spectroscopic and structural studies from X-ray diffraction methods revealed uncommonly long Fe···Fe separations that change by less than 0.3 Å upon the binding of additional bridging ligands. The structural constraints imposed by the protein host on the di-Fe cores are unique and create examples of active sites having entatic states within engineered artificial metalloproteins.
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Affiliation(s)
- Kelsey R Miller
- Department of Chemistry, 1102 Natural Sciences II, University of California, Irvine, California 92697, United States
| | - Saborni Biswas
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Andrew Jasniewski
- Department of Molecular Biology and Biochemistry, University of California, Irvine, California 92697, United States
| | - Alec H Follmer
- Department of Chemistry, 1102 Natural Sciences II, University of California, Irvine, California 92697, United States
| | - Ankita Biswas
- Department of Chemistry, 1102 Natural Sciences II, University of California, Irvine, California 92697, United States
| | - Therese Albert
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Mail Code HRC3, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Sinan Sabuncu
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Mail Code HRC3, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Emile L Bominaar
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Michael P Hendrich
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Pierre Moënne-Loccoz
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Mail Code HRC3, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - A S Borovik
- Department of Chemistry, 1102 Natural Sciences II, University of California, Irvine, California 92697, United States
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34
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Zhang X, Liu L, Li Y. Synthesis and Benzene Hydroxylation Properties of Amino Substituted [FeFe]-Hydrogenase Model Compounds. Catal Letters 2020. [DOI: 10.1007/s10562-020-03197-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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35
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Xi ZH, Sun Y, Wang X, Zhao XL, Han J, Chen XD. Rare earth metal complexes based on a tripodal ligand and their application as highly selective “turn-on” fluorescent probe for Fe3+ ion. INORG CHEM COMMUN 2020. [DOI: 10.1016/j.inoche.2020.108046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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36
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SHINDE N, FURUTACHI H, SAKATA Y, AKINE S, FUJINAMI S, SUZUKI M. Crystal Structure of (μ-Phenoxo)bis(μ-pentafluorobenzoate)dicobalt(II, III) Complex with a Dinucleating Ligand. X-RAY STRUCTURE ANALYSIS ONLINE 2020. [DOI: 10.2116/xraystruct.36.23] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Naho SHINDE
- Department of Chemistry, Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University
| | - Hideki FURUTACHI
- Department of Chemistry, Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University
- WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University
| | - Yoko SAKATA
- Department of Chemistry, Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University
- WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University
| | - Shigehisa AKINE
- Department of Chemistry, Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University
- WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University
| | - Shuhei FUJINAMI
- Department of Chemistry, Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University
| | - Masatatsu SUZUKI
- Department of Chemistry, Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University
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37
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Mondal P, Lovisari M, Twamley B, McDonald AR. Fast Hydrocarbon Oxidation by a High‐Valent Nickel–Fluoride Complex. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202004639] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Prasenjit Mondal
- School of Chemistry Trinity College Dublin The University of Dublin College Green Dublin 2 Ireland
| | - Marta Lovisari
- School of Chemistry Trinity College Dublin The University of Dublin College Green Dublin 2 Ireland
| | - Brendan Twamley
- School of Chemistry Trinity College Dublin The University of Dublin College Green Dublin 2 Ireland
| | - Aidan R. McDonald
- School of Chemistry Trinity College Dublin The University of Dublin College Green Dublin 2 Ireland
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38
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Mondal P, Lovisari M, Twamley B, McDonald AR. Fast Hydrocarbon Oxidation by a High‐Valent Nickel–Fluoride Complex. Angew Chem Int Ed Engl 2020; 59:13044-13050. [DOI: 10.1002/anie.202004639] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Indexed: 11/11/2022]
Affiliation(s)
- Prasenjit Mondal
- School of Chemistry Trinity College Dublin The University of Dublin College Green Dublin 2 Ireland
| | - Marta Lovisari
- School of Chemistry Trinity College Dublin The University of Dublin College Green Dublin 2 Ireland
| | - Brendan Twamley
- School of Chemistry Trinity College Dublin The University of Dublin College Green Dublin 2 Ireland
| | - Aidan R. McDonald
- School of Chemistry Trinity College Dublin The University of Dublin College Green Dublin 2 Ireland
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39
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Banerjee S, Draksharapu A, Crossland PM, Fan R, Guo Y, Swart M, Que L. Sc 3+-Promoted O-O Bond Cleavage of a (μ-1,2-Peroxo)diiron(III) Species Formed from an Iron(II) Precursor and O 2 to Generate a Complex with an Fe IV2(μ-O) 2 Core. J Am Chem Soc 2020; 142:4285-4297. [PMID: 32017545 DOI: 10.1021/jacs.9b12081] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Soluble methane monooxygenase (sMMO) carries out methane oxidation at 4 °C and under ambient pressure in a catalytic cycle involving the formation of a peroxodiiron(III) intermediate (P) from the oxygenation of the diiron(II) enzyme and its subsequent conversion to Q, the diiron(IV) oxidant that hydroxylates methane. Synthetic diiron(IV) complexes that can serve as models for Q are rare and have not been generated by a reaction sequence analogous to that of sMMO. In this work, we show that [FeII(Me3NTB)(CH3CN)](CF3SO3)2 (Me3NTB = tris((1-methyl-1H-benzo[d]imidazol-2-yl)methyl)amine) (1) reacts with O2 in the presence of base, generating a (μ-1,2-peroxo)diiron(III) adduct with a low O-O stretching frequency of 825 cm-1 and a short Fe···Fe distance of 3.07 Å. Even more interesting is the observation that the peroxodiiron(III) complex undergoes O-O bond cleavage upon treatment with the Lewis acid Sc3+ and transforms into a bis(μ-oxo)diiron(IV) complex, thus providing a synthetic precedent for the analogous conversion of P to Q in the catalytic cycle of sMMO.
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Affiliation(s)
- Saikat Banerjee
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Apparao Draksharapu
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Patrick M Crossland
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Ruixi Fan
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Marcel Swart
- ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain.,IQCC and Department of Chemistry, University of Girona, 17003 Girona, Spain
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
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40
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Singh B, Das RS. Studies on the oxidative degradation of paracetamol by a μ-oxo-diiron(III) complex. CAN J CHEM 2020. [DOI: 10.1139/cjc-2019-0193] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In higher organisms, metalloenzymes like cytochrome P450, containing a Fe(III) metal center, play an active role in metabolism of paracetamol (APAP). Here, we have chosen a mimicking μ-oxo-diiron complex, [Fe(III)2(μ-O)(phen)4(H2O)2]4+(1, phen = 1,10-phenanthroline), to study spectrophotometrically the kinetics of the redox interactions with APAP. In acidic buffer media (pH = 3.4–5.1), APAP quantitatively reduces 1 following first-order reaction kinetics. Each molecule of 1 accepts two electrons from APAP and is reduced to ferroin [Fe(phen)3]2+. On oxidation, APAP produces N-acetyl-p-benzoquinone imine (NAPQI), which on hydrolysis results in a mixture of benzoquinone, quinone oxime, acetamide, and acetic acid. In reaction media due to successive deprotonations, 1 exists in equilibrium with the species [Fe(III)2(μ-O)(phen)4(H2O)(OH)]3+(1a) and [Fe(III)2(μ-O)(phen)4(OH)2]2+(1b) (pKa= 3.71 and 5.28, respectively). The kinetic analyses suggest for an unusual reactivity order as 1 < 1a ≫ 1b. The mechanistic possibilities suggest that although 1 is reduced by concerted electron transfer (ET) – proton transfer (PT) mechanism, 1a and 1b may be reduced by a concerted PT–ET mechanism where a slow proton-abstraction step is followed by a rapid ET process. It seems that the initial activation of the bridging μ-oxo group by a proton-abstraction results in the higher reactivity of 1a.
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Affiliation(s)
- Bula Singh
- Department of Chemistry, Visva-Bharati, Santiniketan 731235, India
| | - Ranendu Sekhar Das
- Department of Chemistry, Ranaghat College, Nadia, West Bengal 741201, India
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41
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Walleck S, Glaser T. A Dinucleating Ligand System with Varying Terminal Donors to Mimic Diiron Active Sites. Isr J Chem 2020. [DOI: 10.1002/ijch.201900097] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Stephan Walleck
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie Universität Bielefeld Universitätsstrasse 25 D-33615 Bielefeld Germany
| | - Thorsten Glaser
- Lehrstuhl für Anorganische Chemie I, Fakultät für Chemie Universität Bielefeld Universitätsstrasse 25 D-33615 Bielefeld Germany
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42
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Alkane and alkene oxidation reactions catalyzed by nickel(II) complexes: Effect of ligand factors. Coord Chem Rev 2020. [DOI: 10.1016/j.ccr.2019.213085] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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43
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Singh AP, Joshi RP, Abboud KA, Peralta JE, Christou G. Molecular spin frustration in mixed-chelate Fe5 and Fe6 oxo clusters with high ground state spin values. Polyhedron 2020. [DOI: 10.1016/j.poly.2019.114182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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44
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Liu Y, You T, Wang HX, Tang Z, Zhou CY, Che CM. Iron- and cobalt-catalyzed C(sp3)–H bond functionalization reactions and their application in organic synthesis. Chem Soc Rev 2020; 49:5310-5358. [DOI: 10.1039/d0cs00340a] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This review highlights the developments in iron and cobalt catalyzed C(sp3)–H bond functionalization reactions with emphasis on their applications in organic synthesis, i.e. natural products and pharmaceuticals synthesis and/or modification.
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Affiliation(s)
- Yungen Liu
- Department of Chemistry
- Southern University of Science and Technology
- Shenzhen
- P. R. China
| | - Tingjie You
- Department of Chemistry
- State Key Laboratory of Synthetic Chemistry
- The University of Hong Kong
- Hong Kong
- P. R. China
| | - Hai-Xu Wang
- Department of Chemistry
- State Key Laboratory of Synthetic Chemistry
- The University of Hong Kong
- Hong Kong
- P. R. China
| | - Zhou Tang
- Department of Chemistry
- State Key Laboratory of Synthetic Chemistry
- The University of Hong Kong
- Hong Kong
- P. R. China
| | - Cong-Ying Zhou
- Department of Chemistry
- State Key Laboratory of Synthetic Chemistry
- The University of Hong Kong
- Hong Kong
- P. R. China
| | - Chi-Ming Che
- Department of Chemistry
- Southern University of Science and Technology
- Shenzhen
- P. R. China
- Department of Chemistry
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45
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Unjaroen D, Gericke R, Lovisari M, Nelis D, Mondal P, Pirovano P, Twamley B, Farquhar ER, McDonald AR. High-Valent d 7 Ni III versus d 8 Cu III Oxidants in PCET. Inorg Chem 2019; 58:16838-16848. [PMID: 31804808 DOI: 10.1021/acs.inorgchem.9b03101] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Oxygenases have been postulated to utilize d4 FeIV and d8 CuIII oxidants in proton-coupled electron transfer (PCET) hydrocarbon oxidation. In order to explore the influence the metal ion and d-electron count can hold over the PCET reactivity, two metastable high-valent metal-oxygen adducts, [NiIII(OAc)(L)] (1b) and [CuIII(OAc)(L)] (2b), L = N,N'-(2,6-diisopropylphenyl)-2,6-pyridinedicarboxamidate, were prepared from their low-valent precursors [NiII(OAc)(L)]- (1a) and [CuII(OAc)(L)]- (2a). The complexes 1a/b-2a/b were characterized using nuclear magnetic resonance, Fourier transform infrared, electron paramagnetic resonance, X-ray diffraction, and absorption spectroscopies and mass spectrometry. Both complexes were capable of activating substrates through a concerted PCET mechanism (hydrogen atom transfer, HAT, or concerted proton and electron transfer, CPET). The reactivity of 1b and 2b toward a series of para-substituted 2,6-di-tert-butylphenols (p-X-2,6-DTBP; X = OCH3, C(CH3)3, CH3, H, Br, CN, NO2) was studied, showing similar rates of reaction for both complexes. In the oxidation of xanthene, the d8 CuIII oxidant displayed a small increase in the rate constant compared to that of the d7 NiIII oxidant. The d8 CuIII oxidant was capable of oxidizing a large family of hydrocarbon substrates with bond dissociation enthalpy (BDEC-H) values up to 90 kcal/mol. It was previously observed that exchanging the ancillary anionic donor ligand in such complexes resulted in a 20-fold enhancement in the rate constant, an observation that is further enforced by comparison of 1b and 2b to the literature precedents. In contrast, we observed only minor differences in the rate constants upon comparing 1b to 2b. It was thus concluded that in this case the metal ion has a minor impact, while the ancillary donor ligand yields more kinetic control over HAT/CPET oxidation.
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Affiliation(s)
- Duenpen Unjaroen
- School of Chemistry, Trinity College Dublin , The University of Dublin , College Green , Dublin 2 , Ireland
| | - Robert Gericke
- School of Chemistry, Trinity College Dublin , The University of Dublin , College Green , Dublin 2 , Ireland
| | - Marta Lovisari
- School of Chemistry, Trinity College Dublin , The University of Dublin , College Green , Dublin 2 , Ireland
| | - Daniel Nelis
- School of Chemistry, Trinity College Dublin , The University of Dublin , College Green , Dublin 2 , Ireland
| | - Prasenjit Mondal
- School of Chemistry, Trinity College Dublin , The University of Dublin , College Green , Dublin 2 , Ireland
| | - Paolo Pirovano
- School of Chemistry, Trinity College Dublin , The University of Dublin , College Green , Dublin 2 , Ireland
| | - Brendan Twamley
- School of Chemistry, Trinity College Dublin , The University of Dublin , College Green , Dublin 2 , Ireland
| | - Erik R Farquhar
- Case Western Reserve University Center for Synchrotron Biosciences, National Synchrotron Light Source II , Brookhaven National Laboratory II , Upton , New York 11973 , United States
| | - Aidan R McDonald
- School of Chemistry, Trinity College Dublin , The University of Dublin , College Green , Dublin 2 , Ireland
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46
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Gordon JB, Vilbert AC, DiMucci IM, MacMillan SN, Lancaster KM, Moënne-Loccoz P, Goldberg DP. Activation of Dioxygen by a Mononuclear Nonheme Iron Complex: Sequential Peroxo, Oxo, and Hydroxo Intermediates. J Am Chem Soc 2019; 141:17533-17547. [PMID: 31647656 DOI: 10.1021/jacs.9b05274] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The activation of dioxygen by FeII(Me3TACN)(S2SiMe2) (1) is reported. Reaction of 1 with O2 at -135 °C in 2-MeTHF generates a thiolate-ligated (peroxo)diiron complex FeIII2(O2)(Me3TACN)2(S2SiMe2)2 (2) that was characterized by UV-vis (λmax = 300, 390, 530, 723 nm), Mössbauer (δ = 0.53, |ΔEQ| = 0.76 mm s-1), resonance Raman (RR) (ν(O-O) = 849 cm-1), and X-ray absorption (XAS) spectroscopies. Complex 2 is distinct from the outer-sphere oxidation product 1ox (UV-vis (λmax = 435, 520, 600 nm), Mössbauer (δ = 0.45, |ΔEQ| = 3.6 mm s-1), and EPR (S = 5/2, g = [6.38, 5.53, 1.99])), obtained by one-electron oxidation of 1. Cleavage of the peroxo O-O bond can be initiated either photochemically or thermally to produce a new species assigned as an FeIV(O) complex, FeIV(O)(Me3TACN)(S2SiMe2) (3), which was identified by UV-vis (λmax = 385, 460, 890 nm), Mössbauer (δ = 0.21, |ΔEQ| = 1.57 mm s-1), RR (ν(FeIV═O) = 735 cm-1), and X-ray absorption spectroscopies, as well as reactivity patterns. Reaction of 3 at low temperature with H atom donors gives a new species, FeIII(OH)(Me3TACN)(S2SiMe2) (4). Complex 4 was independently synthesized from 1 by the stoichiometric addition of a one-electron oxidant and a hydroxide source. This work provides a rare example of dioxygen activation at a mononuclear nonheme iron(II) complex that produces both FeIII-O-O-FeIII and FeIV(O) species in the same reaction with O2. It also demonstrates the feasibility of forming Fe/O2 intermediates with strongly donating sulfur ligands while avoiding immediate sulfur oxidation.
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Affiliation(s)
- Jesse B Gordon
- Department of Chemistry , The Johns Hopkins University , 3400 North Charles Street , Baltimore , Maryland 21218 , United States
| | - Avery C Vilbert
- Department of Chemistry and Chemical Biology, Baker Laboratory , Cornell University , Ithaca , New York 14853 , United States
| | - Ida M DiMucci
- Department of Chemistry and Chemical Biology, Baker Laboratory , Cornell University , Ithaca , New York 14853 , United States
| | - Samantha N MacMillan
- Department of Chemistry and Chemical Biology, Baker Laboratory , Cornell University , Ithaca , New York 14853 , United States
| | - Kyle M Lancaster
- Department of Chemistry and Chemical Biology, Baker Laboratory , Cornell University , Ithaca , New York 14853 , United States
| | - Pierre Moënne-Loccoz
- Department of Chemical Physiology and Biochemistry , Oregon Health & Science University , Portland , Oregon 97239 , United States
| | - David P Goldberg
- Department of Chemistry , The Johns Hopkins University , 3400 North Charles Street , Baltimore , Maryland 21218 , United States
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47
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Ghosh K, Chattopadhyay S. Synthetic stratagem and structures of two heteroleptic cobalt(III) complexes acting as biomimetic catalysts: Role of co-ligands in catalytic activities. Polyhedron 2019. [DOI: 10.1016/j.poly.2019.05.062] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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48
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Johnson EJ, Kleinlein C, Musgrave RA, Betley TA. Diiron oxo reactivity in a weak-field environment. Chem Sci 2019; 10:6304-6310. [PMID: 31341583 PMCID: PMC6598509 DOI: 10.1039/c9sc00605b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Accepted: 05/08/2019] [Indexed: 11/21/2022] Open
Abstract
Concomitant deprotonation and metalation of a dinucleating cofacial Pacman dipyrrin ligand platform tBudmxH2 with Fe2(Mes)4 results in formation of a diiron complex ( tBudmx)Fe2(Mes)2. Treatment of ( tBudmx)Fe2(Mes)2 with one equivalent of water yields the diiron μ-oxo complex ( tBudmx)Fe2(μ-O) and free mesitylene. A two-electron oxidation of ( tBudmx)Fe2(μ-O) gives rise to the diferric complex ( tBudmx)Fe2(μ-O)Cl2, and one-electron reduction from this FeIIIFeIII state allows for isolation of a mixed-valent species [Cp2Co][( tBudmx)Fe2(μ-O)Cl2]. Both ( tBudmx)Fe2(μ-O) and [Cp2Co][( tBudmx)Fe2(μ-O)Cl2] exhibit basic character at the bridging oxygen atom and can be protonated using weak acids to form bridging diferrous hydroxide species. The basicity of the diferrous oxo ( tBudmx)Fe2(μ-O) is quantified through studies of the pK a of its conjugate acid, [( tBudmx)Fe2(μ-OH)]+, which is determined to be 15.3(6); interestingly, upon coordination of neutral solvent ligands to yield ( tBudmx)Fe2(μ-O)(thf)2, the basicity is increased as observed through an increase in the pK a of the conjugate acid [( tBudmx)Fe2(μ-OH)(thf)2]+ to 26.8(6). In contrast, attempts to synthesize a diferric bridging hydroxide by two-electron oxidation of [( tBudmx)Fe2(μ-OH)(thf)2]+ resulted in isolation of ( tBudmx)Fe2(μ-O)Cl2 with concomitant loss of a proton, consistent with the pK a of the conjugate acid [( tBudmx)Fe2(μ-OH)Cl2]+ determined computationally to be -1.8(6). The foregoing results highlight the intricate interplay between oxidation state and reactivity in diiron μ-oxo units.
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Affiliation(s)
- Elizabeth J Johnson
- Department of Chemistry and Chemical Biology , Harvard University , Cambridge , MA 02138 , USA .
| | - Claudia Kleinlein
- Department of Chemistry and Chemical Biology , Harvard University , Cambridge , MA 02138 , USA .
| | - Rebecca A Musgrave
- Department of Chemistry and Chemical Biology , Harvard University , Cambridge , MA 02138 , USA .
| | - Theodore A Betley
- Department of Chemistry and Chemical Biology , Harvard University , Cambridge , MA 02138 , USA .
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49
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Zhang H, Hatzis GP, Moore CE, Dickie DA, Bezpalko MW, Foxman BM, Thomas CM. O 2 Activation by a Heterobimetallic Zr/Co Complex. J Am Chem Soc 2019; 141:9516-9520. [PMID: 31184140 DOI: 10.1021/jacs.9b04215] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Oxygen reduction is a critical half reaction in renewable fuel cell development and a key step in the development of aerobic oxidation reactions. Herein, we report rapid two-electron O2 reduction by a d0 ZrIV center with an appended redox-active Co-I site serving as an electron reservoir. The early/late heterobimetallic Zr/Co complex (THF)Zr(MesNP iPr2)3CoCN tBu (1) reacts readily with O2 and O atom transfer reagents to generate reactive oxygenated species including terminal peroxo and oxo complexes, (O2)Zr(MesNP iPr2)3CoCN tBu (2) and O≡Zr(MesNP iPr2)3CoCN tBu (3). The bimetallic Zr/Co complex provides a new cooperative synthetic pathway to promote multielectron redox processes such as oxygen reduction, with each metal playing a distinct role as a substrate binding site or redox mediator.
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Affiliation(s)
- Hongtu Zhang
- Department of Chemistry and Biochemistry , The Ohio State University , 100 West 18th Avenue , Columbus , Ohio 43210 , United States
| | - Gregory P Hatzis
- Department of Chemistry and Biochemistry , The Ohio State University , 100 West 18th Avenue , Columbus , Ohio 43210 , United States
| | - Curtis E Moore
- Department of Chemistry and Biochemistry , The Ohio State University , 100 West 18th Avenue , Columbus , Ohio 43210 , United States
| | - Diane A Dickie
- Department of Chemistry , Brandeis University , 415 South Street , Waltham , Massachusetts 02454 , United States
| | - Mark W Bezpalko
- Department of Chemistry , Brandeis University , 415 South Street , Waltham , Massachusetts 02454 , United States
| | - Bruce M Foxman
- Department of Chemistry , Brandeis University , 415 South Street , Waltham , Massachusetts 02454 , United States
| | - Christine M Thomas
- Department of Chemistry and Biochemistry , The Ohio State University , 100 West 18th Avenue , Columbus , Ohio 43210 , United States
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50
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Barman SK, Cano J, Lloret F, Mukherjee R. Single-Molecule-Magnet FeII4FeIII2 and Antiferromagnetic FeIII4 Coordination Clusters. Inorg Chem 2019; 58:8086-8099. [DOI: 10.1021/acs.inorgchem.9b00828] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Suman K. Barman
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208 016, India
| | - Joan Cano
- Departament de Química, Inorgànica/Instituto de Ciencia Molecular (ICMOL), Universitat de València, Polígono de
la Coma, s/n, 46980 Paterna (València), Spain
| | - Francesc Lloret
- Departament de Química, Inorgànica/Instituto de Ciencia Molecular (ICMOL), Universitat de València, Polígono de
la Coma, s/n, 46980 Paterna (València), Spain
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