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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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2
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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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3
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Payard P, Zheng Y, Zhou W, Khrouz L, Bonneviot L, Wischert R, Grimaud L, Pera‐Titus M. Iron Triflate Salts as Highly Active Catalysts for the Solvent‐Free Oxidation of Cyclohexane. European J Org Chem 2020. [DOI: 10.1002/ejoc.202000263] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Pierre‐Adrien Payard
- Eco‐Efficient Products and Processes Laboratory (E2P2L) UMI 3464 CNRS Solvay 3966 Jin Du Road, Xin Zhuang Ind Zone 201108 Shanghai China
- Laboratoire des Biomolécules LBM PSL University, Sorbonne Université 24 rue Lhomond 75005 Paris France
| | - Yu‐Ting Zheng
- Eco‐Efficient Products and Processes Laboratory (E2P2L) UMI 3464 CNRS Solvay 3966 Jin Du Road, Xin Zhuang Ind Zone 201108 Shanghai China
| | - Wen‐Juan Zhou
- Eco‐Efficient Products and Processes Laboratory (E2P2L) UMI 3464 CNRS Solvay 3966 Jin Du Road, Xin Zhuang Ind Zone 201108 Shanghai China
| | - Lhoussain Khrouz
- Université Claude Bernard Lyon 1, Laboratoire de Chimie LBM Univ Lyon, ENS de Lyon, CNRS UMR 5182 46 Allée d'Italie 69342 Lyon France
| | - Laurent Bonneviot
- Université Claude Bernard Lyon 1, Laboratoire de Chimie LBM Univ Lyon, ENS de Lyon, CNRS UMR 5182 46 Allée d'Italie 69342 Lyon France
| | - Raphael Wischert
- Eco‐Efficient Products and Processes Laboratory (E2P2L) UMI 3464 CNRS Solvay 3966 Jin Du Road, Xin Zhuang Ind Zone 201108 Shanghai China
| | - Laurence Grimaud
- Laboratoire des Biomolécules LBM PSL University, Sorbonne Université 24 rue Lhomond 75005 Paris France
| | - Marc Pera‐Titus
- Eco‐Efficient Products and Processes Laboratory (E2P2L) UMI 3464 CNRS Solvay 3966 Jin Du Road, Xin Zhuang Ind Zone 201108 Shanghai China
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4
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Basak T, Ghosh K, Gómez-García CJ, Chattopadhyay S. Synthesis, structure and magnetic characterization of a dinuclear and two mononuclear iron(III) complexes with N,O-donor Schiff base ligands. Polyhedron 2018. [DOI: 10.1016/j.poly.2017.12.040] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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5
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Qin H, Jiang X, Huang H, Liu W, Li J, Xiao Y, Mao L, Fu Z, Yu N, Yin D. Ionic liquid-assisted catalytic oxidation of anethole by copper- and iron-based metal-organic frameworks. MOLECULAR CATALYSIS 2017. [DOI: 10.1016/j.mcat.2017.07.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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6
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Ghosh M, Pattanayak S, Dhar BB, Singh KK, Panda C, Sen Gupta S. Selective C-H Bond Oxidation Catalyzed by the Fe-bTAML Complex: Mechanistic Implications. Inorg Chem 2017; 56:10852-10860. [PMID: 28841016 DOI: 10.1021/acs.inorgchem.7b00453] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Nonheme iron complexes bearing tetradentate N-atom-donor ligands with cis labile sites show great promise for chemoselective aliphatic C-H hydroxylation. However, several challenges still limit their widespread application. We report a mechanism-guided development of a peroxidase mimicking iron complex based on the bTAML macrocyclic ligand framework (Fe-bTAML: biuret-modified tetraamido macrocyclic ligand) as a catalyst to perform selective oxidation of unactivated 3° bonds with unprecedented regioselectivity (3°:2° of 110:1 for adamantane oxidation), high stereoretention (99%), and turnover numbers (TONs) up to 300 using mCPBA as the oxidant. Ligand decomposition pathways involving acid-induced demetalation were identified, and this led to the development of more robust and efficient Fe-bTAML complexes that catalyzed chemoselective C-H oxidation. Mechanistic studies, which include correlation of the product formed with the FeV(O) reactive intermediates generated during the reaction, indicate that the major pathway involves the cleavage of C-H bonds by FeV(O). When these oxidations were performed in the presence of air, the yield of the oxidized product doubled, but the stereoretention remained unchanged. On the basis of 18O labeling and other mechanistic studies, we propose a mechanism that involves the dual activation of mCPBA and O2 by Fe-bTAML, leading to formation of the FeV(O) intermediate. This high-valent iron oxo remains the active intermediate for most of the reaction, resulting in high regio- and stereoselectivity during product formation.
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Affiliation(s)
- Munmun Ghosh
- Chemical Engineering Division, CSIR, National Chemical Laboratory , Pune 411008, India
| | - Santanu Pattanayak
- Chemical Engineering Division, CSIR, National Chemical Laboratory , Pune 411008, India
| | - Basab B Dhar
- Department of Chemistry, Shiv Nadar University , Gautam Buddha Nagar, Uttar Pradesh 201314, India
| | - Kundan K Singh
- Chemical Engineering Division, CSIR, National Chemical Laboratory , Pune 411008, India
| | - Chakadola Panda
- Chemical Engineering Division, CSIR, National Chemical Laboratory , Pune 411008, India
| | - Sayam Sen Gupta
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata , Mohanpur 741246, India
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7
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Ansari A, Rajaraman G. ortho-Hydroxylation of aromatic acids by a non-heme Fe(V)=O species: how important is the ligand design? Phys Chem Chem Phys 2015; 16:14601-13. [PMID: 24812659 DOI: 10.1039/c3cp55430a] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
There is a growing interest in probing the mechanism of catalytic transformations effected by non-heme iron-oxo complexes as these reactions set a platform for understanding the relevant enzymatic reactions. The ortho-hydroxylation of aromatic compounds is one such reaction catalysed by iron-oxo complexes. Experimentally [Fe(II)(BPMEN)(CH3CN)2](2+) (1) and [Fe(II)(TPA)(CH3CN)2](2+) (2) (where TPA = tris(2-pyridylmethyl)amine and BPMEN = N,N′-dimethyl-N,N′-bis(2-pyridylmethyl)ethane-1,2-diamine) complexes containing amino pyridine ligands along with H2O2 are employed to carry out these transformations where complex 1 is found to be more reactive than complex 2. Herein, using density functional methods employing B3LYP and dispersion corrected B3LYP (B3LYP-D) functionals, we have explored the mechanism of this reaction to reason out the importance of ligand design in fine-tuning the reactivity of such catalytic transformations. Dispersion corrected B3LYP is found to be superior to B3LYP in predicting the correct ground state of these species and also yields lower barrier heights than the B3LYP functional. Starting the reaction from the Fe(III)–OOH species, both homolytic and heterolytic cleavage of the O···O bond is explored leading to the formation of the transient Fe(IV)=O and Fe(V)=O species. For both the ligand systems, heterolytic cleavage was energetically preferable and our calculations suggest that both the reactions are catalyzed by an elusive high-valent Fe(V)=O species. The Fe(V)=O species undergoes the reaction via an electrophilic attack of the benzene ring to effect the ortho-hydroxylation reaction. The reactivity pattern observed for 1 and 2 are reflected in the computed barrier heights for the ortho-hydroxylation reaction. Electronic structure analysis reveals that the difference in reactivity between the ligand architectures described in complex 1 and 2 arise due to orientation of the pyridine ring(s) parallel or perpendicular to the Fe(V)=O bond. The parallel orientation of the pyridine ring is found to mix with the (πFe(dyz)–O(py))* orbital of the Fe-oxo bond leading to a reduction in the electrophilicity of the ferryl oxygen atom. Our calculations highlight the importance of ligand design in this chemistry and suggest that this concept can be used to (i) stabilize high-valent intermediates which can be trapped and thoroughly characterized (ii) enhance the reactivity and efficiency of the oxidants by increasing the electrophilicity of the ferryl oxygen containing FeVO species. Our computed results are in general agreement with the experimental results.
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Affiliation(s)
- Azaj Ansari
- Department of Chemistry, Indian Institute of Technology-Bombay, Powai, Mumbai, India.
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8
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9
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Oxidation of alkenes with non-heme iron complexes: suitability as an organic synthetic method. Tetrahedron 2014. [DOI: 10.1016/j.tet.2014.10.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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10
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Highly selective and direct oxidation of cyclohexane to cyclohexanone over vanadium exchanged NaY at room temperature under solvent-free conditions. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/j.molcata.2014.05.027] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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11
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Liu J, Liu R, Li H, Kong W, Huang H, Liu Y, Kang Z. Au nanoparticles in carbon nanotubes with high photocatalytic activity for hydrocarbon selective oxidation. Dalton Trans 2014; 43:12982-8. [DOI: 10.1039/c4dt01077a] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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12
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Zhang C, Liu C, Shao Y, Bao X, Wan X. Nucleophilic Attack of α-Aminoalkyl Radicals on CarbonNitrogen Triple Bonds to Construct α-Amino Nitriles: An Experimental and Computational Study. Chemistry 2013; 19:17917-25. [DOI: 10.1002/chem.201303296] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Indexed: 01/09/2023]
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13
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Highly efficient oxidation of diphenylmethane to benzophenone employing a novel ruthenium catalyst with tert-butylhydroperoxide under mild conditions. CATAL COMMUN 2013. [DOI: 10.1016/j.catcom.2013.03.031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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14
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Lenze M, Sedinkin SL, Bauer EB. Polydentate pyridyl ligands and the catalytic activity of their iron(II) complexes in oxidation reactions utilizing peroxides as the oxidants. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.molcata.2013.03.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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15
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Ansari A, Kaushik A, Rajaraman G. Mechanistic Insights on the ortho-Hydroxylation of Aromatic Compounds by Non-heme Iron Complex: A Computational Case Study on the Comparative Oxidative Ability of Ferric-Hydroperoxo and High-Valent FeIV═O and FeV═O Intermediates. J Am Chem Soc 2013; 135:4235-49. [DOI: 10.1021/ja307077f] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Azaj Ansari
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Abhishek Kaushik
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
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16
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Iron(II) α-Aminopyridine Complexes and Their Catalytic Activity in Oxidation Reactions: A Comparative Study of Activity and Ligand Decomposition. Chempluschem 2012. [DOI: 10.1002/cplu.201200244] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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17
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Talsi EP, Bryliakov KP. Chemo- and stereoselective CH oxidations and epoxidations/cis-dihydroxylations with H2O2, catalyzed by non-heme iron and manganese complexes. Coord Chem Rev 2012. [DOI: 10.1016/j.ccr.2012.04.005] [Citation(s) in RCA: 314] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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18
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Ye W, Staples RJ, Rybak-Akimova EV. Oxygen atom transfer mediated by an iron(IV)/iron(II) macrocyclic complex containing pyridine and tertiary amine donors. J Inorg Biochem 2012; 115:1-12. [PMID: 22922287 DOI: 10.1016/j.jinorgbio.2012.05.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2011] [Revised: 05/08/2012] [Accepted: 05/10/2012] [Indexed: 11/19/2022]
Abstract
A new non-heme iron model complex containing a high-spin iron(II) complexed with N-methylated pyridine-containing macrocycle was synthesized and crystallographically characterized. The complex generates peroxo- and high-valent iron-oxo intermediates in reactions with tert-butylhydroperoxide and isopropyl 2-iodoxybenzoate, respectively, allowing to gain insight into the formation and reactivity of enzyme-like intermediates related to biological oxygen activation. The formation and reactivity of these intermediate species were investigated by the stopped-flow methodology. The mechanism of oxygen transfer to organic substrates involving reaction of oxoiron(IV) intermediate was elucidated on the basis of spectroscopic and kinetic data. Incorporation of a pyridine ring into the macrocycle increased the reactivity of the Fe(IV)=O intermediates in comparison with polyamine tetraaza macrocyclic complexes: ferryl (Fe(IV)=O) species derived from 3 demonstrated electrophilic reactivity in transferring an oxygen atom to substituted triarylphosphines and to olefins (such as cyclooctene). However, iron(III) alkylperoxo intermediate was unreactive with cyclooctene.
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Affiliation(s)
- Wanhua Ye
- Department of Chemistry, Tufts University, Medford, MA 02155, USA
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19
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Company A, Lloret J, Gómez L, Costas M. Alkane C–H Oxygenation Catalyzed by Transition Metal Complexes. CATALYSIS BY METAL COMPLEXES 2012. [DOI: 10.1007/978-90-481-3698-8_5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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20
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Kojima T, Nakayama K, Sakaguchi M, Ogura T, Ohkubo K, Fukuzumi S. Photochemical Activation of Ruthenium(II)–Pyridylamine Complexes Having a Pyridine-N-Oxide Pendant toward Oxygenation of Organic Substrates. J Am Chem Soc 2011; 133:17901-11. [DOI: 10.1021/ja207572z] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Takahiko Kojima
- Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8571, Japan
| | | | - Miyuki Sakaguchi
- Graduate School of Life Science, University of Hyogo, Kouto, Hyogo 678-1297, Japan
| | - Takashi Ogura
- Graduate School of Life Science, University of Hyogo, Kouto, Hyogo 678-1297, Japan
| | | | - Shunichi Fukuzumi
- Department of Bioinspired Science, Ewha Womans University, Seoul 120-750, South Korea
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21
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Bruijnincx PCA, Buurmans ILC, Huang Y, Juhász G, Viciano-Chumillas M, Quesada M, Reedijk J, Lutz M, Spek AL, Münck E, Bominaar EL, Klein Gebbink RJM. Mono- and dinuclear iron complexes of bis(1-methylimidazol-2-yl)ketone (bik): structure, magnetic properties, and catalytic oxidation studies. Inorg Chem 2011; 50:9243-55. [PMID: 21902227 PMCID: PMC3221465 DOI: 10.1021/ic200332y] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The newly synthesized dinuclear complex [Fe(III)(2)(μ-OH)(2)(bik)(4)](NO(3))(4) (1) (bik, bis(1-methylimidazol-2-yl)ketone) shows rather short Fe···Fe (3.0723(6) Å) and Fe-O distances (1.941(2)/1.949(2) Å) compared to other unsupported Fe(III)(2)(μ-OH)(2) complexes. The bridging hydroxide groups of 1 are strongly hydrogen-bonded to a nitrate anion. The (57)Fe isomer shift (δ = 0.45 mm s(-1)) and quadrupole splitting (ΔE(Q) = 0.26 mm s(-1)) obtained from Mössbauer spectroscopy are consistent with the presence of two identical high-spin iron(III) sites. Variable-temperature magnetic susceptibility studies revealed antiferromagnetic exchange (J = 35.9 cm(-1) and H = JS(1)·S(2)) of the metal ions. The optimized DFT geometry of the cation of 1 in the gas phase agrees well with the crystal structure, but both the Fe···Fe and Fe-OH distances are overestimated (3.281 and 2.034 Å, respectively). The agreement in these parameters improves dramatically (3.074 and 1.966 Å) when the hydrogen-bonded nitrate groups are included, reducing the value calculated for J by 35%. Spontaneous reduction of 1 was observed in methanol, yielding a blue [Fe(II)(bik)(3)](2+) species. Variable-temperature magnetic susceptibility measurements of [Fe(II)(bik)(3)](OTf)(2) (2) revealed spin-crossover behavior. Thermal hysteresis was observed with 2, due to a loss of cocrystallized solvent molecules, as monitored by thermogravimetric analysis. The hysteresis disappears once the solvent is fully depleted by thermal cycling. [Fe(II)(bik)(3)](OTf)(2) (2) catalyzes the oxidation of alkanes with t-BuOOH. High selectivity for tertiary C-H bond oxidation was observed with adamantane (3°/2° value of 29.6); low alcohol/ketone ratios in cyclohexane and ethylbenzene oxidation, a strong dependence of total turnover number on the presence of O(2), and a low retention of configuration in cis-1,2-dimethylcyclohexane oxidation were observed. Stereoselective oxidation of olefins with dihydrogen peroxide yielding epoxides was observed under both limiting oxidant and substrate conditions.
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Affiliation(s)
- Pieter C. A. Bruijnincx
- Organic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Inge L. C. Buurmans
- Organic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Yuxing Huang
- Organic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Gergely Juhász
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Marta Viciano-Chumillas
- Leiden Institute of Chemistry, Leiden University, Coordination and Bioinorganic Chemistry Group, P. O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Manuel Quesada
- Leiden Institute of Chemistry, Leiden University, Coordination and Bioinorganic Chemistry Group, P. O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Jan Reedijk
- Leiden Institute of Chemistry, Leiden University, Coordination and Bioinorganic Chemistry Group, P. O. Box 9502, 2300 RA Leiden, The Netherlands
- Department of Chemistry, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Martin Lutz
- Bijvoet Center for Biomolecular Research, Crystal and Structural Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Anthony L. Spek
- Bijvoet Center for Biomolecular Research, Crystal and Structural Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Eckard Münck
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Emile L. Bominaar
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Robertus J. M. Klein Gebbink
- Organic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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22
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Proximity effect on the general base catalysed hydrolysis of amide linkage: The role of cationic surfactant, CTABr. J CHEM SCI 2011. [DOI: 10.1007/s12039-011-0084-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Makhlynets OV, Rybak-Akimova EV. Aromatic hydroxylation at a non-heme iron center: observed intermediates and insights into the nature of the active species. Chemistry 2011; 16:13995-4006. [PMID: 21117047 DOI: 10.1002/chem.201002577] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mechanism of substrate oxidations with hydrogen peroxide in the presence of a highly reactive, biomimetic, iron aminopyridine complex, [Fe(II)(bpmen)(CH(3)CN)(2)][ClO(4)](2) (1; bpmen=N,N'-dimethyl-N,N'-bis(2-pyridylmethyl)ethane-1,2-diamine), is elucidated. Complex 1 has been shown to be an excellent catalyst for epoxidation and functional-group-directed aromatic hydroxylation using H(2)O(2), although its mechanism of action remains largely unknown. Efficient intermolecular hydroxylation of unfunctionalized benzene and substituted benzenes with H(2)O(2) in the presence of 1 is found in the present work. Detailed mechanistic studies of the formation of iron(III)-phenolate products are reported. We have identified, generated in high yield, and experimentally characterized the key Fe(III)(OOH) intermediate (λ(max)=560 nm, rhombic EPR signal with g=2.21, 2.14, 1.96) formed by 1 and H(2)O(2). Stopped-flow kinetic studies showed that Fe(III)(OOH) does not directly hydroxylate the aromatic rings, but undergoes rate-limiting self-decomposition producing transient reactive oxidant. The formation of the reactive species is facilitated by acid-assisted cleavage of the O-O bond in the iron-hydroperoxide intermediate. Acid-assisted benzene hydroxylation with 1 and a mechanistic probe, 2-Methyl-1-phenyl-2-propyl hydroperoxide (MPPH), correlates with O-O bond heterolysis. Independently generated Fe(IV)=O species, which may originate from O-O bond homolysis in Fe(III)(OOH), proved to be inactive toward aromatic substrates. The reactive oxidant derived from 1 exchanges its oxygen atom with water and electrophilically attacks the aromatic ring (giving rise to an inverse H/D kinetic isotope effect of 0.8). These results have revealed a detailed experimental mechanistic picture of the oxidation reactions catalyzed by 1, based on direct characterization of the intermediates and products, and kinetic analysis of the individual reaction steps. Our detailed understanding of the mechanism of this reaction revealed both similarities and differences between synthetic and enzymatic aromatic hydroxylation reactions.
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Affiliation(s)
- Olga V Makhlynets
- Department of Chemistry, Tufts University, 62 Talbot Ave., Medford, MA 02155, USA
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24
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Shejwalkar P, Rath NP, Bauer EB. New iron(ii) α-iminopyridine complexes and their catalytic activity in the oxidation of activated methylene groups and secondary alcohols to ketones. Dalton Trans 2011; 40:7617-31. [DOI: 10.1039/c1dt10387c] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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25
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Vad MS, Nielsen A, Lennartson A, Bond AD, McGrady JE, McKenzie CJ. Switching on oxygen activation by cobalt complexes of pentadentate ligands. Dalton Trans 2011; 40:10698-707. [DOI: 10.1039/c1dt10594a] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Collinson S, Thielemans W. The catalytic oxidation of biomass to new materials focusing on starch, cellulose and lignin. Coord Chem Rev 2010. [DOI: 10.1016/j.ccr.2010.04.007] [Citation(s) in RCA: 165] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Biswas AN, Pariyar A, Bose S, Das P, Bandyopadhyay P. Mild oxidation of hydrocarbons catalyzed by iron corrole with tert-butylhydroperoxide. CATAL COMMUN 2010. [DOI: 10.1016/j.catcom.2010.05.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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Mayilmurugan R, Stoeckli-Evans H, Suresh E, Palaniandavar M. Chemoselective and biomimetic hydroxylation of hydrocarbons by non-heme μ-oxo-bridged diiron(iii) catalysts using m-CPBA as oxidant. Dalton Trans 2009:5101-14. [DOI: 10.1039/b820771b] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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Yeung HL, Sham KC, Tsang CS, Lau TC, Kwong HL. A chiral iron-sexipyridine complex as a catalyst for alkene epoxidation with hydrogen peroxide. Chem Commun (Camb) 2008:3801-3. [DOI: 10.1039/b804281k] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Characterization and Properties of Non-Heme Iron Peroxo Complexes. STRUCTURE AND BONDING 2007. [DOI: 10.1007/3-540-46592-8_6] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
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31
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Mononuclear diastereopure non-heme Fe(II) complexes of pentadentate ligands with pyrrolidinyl moieties: Structural studies, and alkene and sulfide oxidation. Inorganica Chim Acta 2007. [DOI: 10.1016/j.ica.2006.08.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Chellamani A, Alhaji NI, Rajagopal S. Kinetics and mechanism of (salen)MnIII–catalysed hydrogen peroxide oxidation of alkyl aryl sulphides. J PHYS ORG CHEM 2007. [DOI: 10.1002/poc.1160] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Díaz-Requejo MM, Belderrain TR, Nicasio MC, Pérez PJ. The carbene insertion methodology for the catalytic functionalization of unreactive hydrocarbons: no classical C-H activation, but efficient C-H functionalization. Dalton Trans 2006:5559-66. [PMID: 17225892 DOI: 10.1039/b610183f] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This contribution intends to highlight the use of the metal-catalyzed functionalization of unreactive carbon-hydrogen bonds by the carbene insertion methodology, that employs diazo compounds as the carbene source.
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Affiliation(s)
- M Mar Díaz-Requejo
- Laboratorio de Catálisis Homogénea, Departamento de Química y Ciencia de los Materiales, Unidad Asociada al CSIC, Universidad de Huelva, Campus de El Carmen, 21007, Huelva, Spain
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34
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Syntheses, structures, and properties of Co(III) complexes derived from polypyridine ligands containing one carboxamido nitrogen donor. Inorganica Chim Acta 2006. [DOI: 10.1016/j.ica.2006.04.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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35
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Shul’pin GB, Kudinov AR, Shul’pina LS, Petrovskaya EA. Oxidations catalyzed by osmium compounds. Part 1: Efficient alkane oxidation with peroxides catalyzed by an olefin carbonyl osmium(0) complex. J Organomet Chem 2006. [DOI: 10.1016/j.jorganchem.2005.10.028] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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36
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Li F, Wang M, Ma C, Gao A, Chen H, Sun L. Mono- and binuclear complexes of iron(ii) and iron(iii) with an N4O ligand: synthesis, structures and catalytic properties in alkane oxidation. Dalton Trans 2006:2427-34. [PMID: 16705341 DOI: 10.1039/b516697g] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Three mononuclear iron complexes and one binuclear iron complex, [Fe(tpoen)Cl].0.5(Fe2OCl6) (1), [Fe(tpoen)Cl]PF6 (2), Fe(tpoen)Cl3 (3) and [[Fe(tpoen)]2(mu-O)](ClO4)4 (4) (tpoen = N-(2-pyridylmethoxyethyl)-N,N-bis(2-pyridylmethyl)amine), were synthesized as functional models of non-heme iron oxygenases. Crystallographic studies revealed that the Fe(II) center of 1 is in a pseudooctahedral environment with a pentadentate N4O ligand and a chloride ion trans to the oxygen atom. The Fe(III) center of 3 is ligated by three nitrogen atoms of tpoen and three chloride ions in a facial configuration. Each Fe(III) center of 4 is coordinated with four nitrogen atoms and an oxygen atom of tpoen with the Fe-O-Fe angle of 172.0(3) angstroms. Complexes 2, 3 and 4 catalysed the oxidation of cyclohexane with H2O2 in the total TNs of 24-36 with A/K ratios of 1.9-2.4. Under the same conditions they also catalysed both the oxidation of ethylbenzene to benzylic alcohol and acetobenzene with good activity (30-47 TN) and low selectivity (A/K 0.7), and the oxidation of adamantane with moderate activity (15-18 TN) and low regioselectivity (3 degrees/2 degrees 3.0-3.2). With mCPBA as oxidant the catalytic activities of 2, 3 and 4 increased 1.8 to 2.3-fold for the oxidation of cyclohexane and ethylbenzene and 6.3 to 7.5-fold for the oxidation of adamantane. Drastic enhancement of the regioselectivity was observed in the oxidation of adamantane (3 degrees/2 degrees 18.5-30.3).
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Affiliation(s)
- Fei Li
- State Key Laboratory of Fine Chemicals, Dalian University of Technology, Zhongshan Road 158-46, Dalian, 116012, China
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37
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Synthesis, structure and catalytic activity of low-spin dicyano iron(III) complexes of N,N′-bis(quinolyl)malonamide derivatives. Inorganica Chim Acta 2004. [DOI: 10.1016/j.ica.2004.01.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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38
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Costas M, Mehn MP, Jensen MP, Que L. Dioxygen Activation at Mononuclear Nonheme Iron Active Sites: Enzymes, Models, and Intermediates. Chem Rev 2004; 104:939-86. [PMID: 14871146 DOI: 10.1021/cr020628n] [Citation(s) in RCA: 2014] [Impact Index Per Article: 100.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Miquel Costas
- Departament de Quimica, Universitat de Girona, 17071, Girona, Spain
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39
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Kopylovich M, Kirillov A, Baev A, Pombeiro A. Heteronuclear iron(III)–chromium(III) hydroxo complexes and hydroxides, and their catalytic activity towards peroxidative oxidation of alkanes. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s1381-1169(03)00420-5] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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40
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Funabiki T. Functional model oxygenations by nonheme iron complexes. ADVANCES IN CATALYTIC ACTIVATION OF DIOXYGEN BY METAL COMPLEXES 2003. [DOI: 10.1007/0-306-47816-1_4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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41
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Lobanova MV, Bryliakov KP, Duban EA, Talsi EP. Stability of low-spin ferric hydroperoxo and alkylperoxo complexes with tris(2-pyridylmethyl)amine. MENDELEEV COMMUNICATIONS 2003. [DOI: 10.1070/mc2003v013n04abeh001727] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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42
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Patra AK, Olmstead MM, Mascharak PK. Spontaneous reduction of a low-spin Fe(III) complex of a neutral pentadentate N(5) Schiff base ligand to the corresponding Fe(II) species in acetonitrile. Inorg Chem 2002; 41:5403-9. [PMID: 12377034 DOI: 10.1021/ic020373w] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The iron complexes of a designed pentadentate Schiff base ligand N,N-bis(2-pyridylmethyl)amine-N-ethyl-2-pyridine-2-aldimine (SBPy(3)) have been synthesized. The low-spin mononuclear Fe(III) complex [(SBPy(3))Fe(DMF)](ClO(4))(3) (2), though stable in the solid state, is spontaneously reduced to the corresponding Fe(II) species [(SBPy(3))Fe(MeCN)](2+) in MeCN. Fe(II) complex [(SBPy(3))Fe(MeCN)](BF(4))(2) (3) has been isolated independently and characterized by crystallography. Electrochemical studies indicate that SBPy(3), like other pentadentate polypyridine ligands, stabilizes the Fe(II) center to a great extent (E(1/2) = 1.01 V vs SCE in MeCN). This fact is responsible for the ready reduction of 2. It is evident that such reactivity has brought complications in the syntheses of iron complexes of polypyridine ligands reported in previous accounts. Very low solubility of 2 in MeOH has allowed isolation of analytically pure 2 in the present work. Storage of dilute methanolic solution of 2 results in the formation of the mu-oxo Fe(III) dimer [(SBPy(3))FeOFe(SBPy(3))](ClO(4))(4) (5), the structure of which has also been determined. Fe(II) complex 3 reacts with CN(-) to afford cyanide adduct [(SBPy(3))Fe(CN)](BF(4)) (4) but does not exhibit any reactivity toward NO. The azomethine moiety (CH=N-py) of 2 is rapidly oxidized by H(2)O(2) to a pyridine-2-carboxamido (C(=O)-N-py) unit and affords [(PaPy(3))Fe(MeCN)](ClO(4))(2) (1), a complex previously reported by us.
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Affiliation(s)
- Apurba K Patra
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA
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Rowland JM, Olmstead MM, Mascharak PK. Unusual reactivity of methylene group adjacent to pyridine-2-carboxamido moiety in iron(III) and cobalt(III) complexes. Inorg Chem 2002; 41:2754-60. [PMID: 12005500 DOI: 10.1021/ic011197e] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The Fe(III) and Co(III) complexes of the ligand N-(2-picolyl)picolinamide (pmpH; H represents the dissociable amide hydrogen), namely, [Fe(pmp)(2)]BF(4) (1) and [Co(pmp)(2)]ClO(4) (2), have been synthesized and structurally characterized. The [bond]CH(2)[bond] moiety of pmp(-) in [M(pmp)(2)](+) (M = Fe, Co) is very reactive and is readily converted to carbonyl (C[double bond]O) group upon exposure to dioxygen. Such conversion results in [M(bpca)(2)]ClO(4) complexes (M = Fe (3), Co (5); bpcaH = bis(2-pyridylcarbonyl)amine) which have been characterized by spectroscopy and X-ray diffraction. The structure of 5 is reported here for the first time. The reactivity of the [bond]CH(2)[bond] moiety of pmp(-) has so far precluded the isolation of 1 although other metal complexes of pmp(-) have been reported years ago. The CH(2) --> C[double bond]O transformation arises from the tendency of the coordinated pmp(-) ligand to achieve further conjugation in the ligand framework and provides a better way to synthesize the metal complexes of bpcaH ligand. Reaction of 3 with NaH affords Fe(II) complex [Fe(bpca)(2)] (4) without any reduction of the ligand frame.
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Affiliation(s)
- John M Rowland
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, USA
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Bartoli JF, Lambert F, Morgenstern-Badarau I, Battioni P, Mansuy D. Unusual efficiency of a non-heme iron complex as catalyst for the hydroxylation of aromatic compounds by hydrogen peroxide: comparison with iron porphyrins. CR CHIM 2002. [DOI: 10.1016/s1631-0748(02)01375-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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45
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Rowland JM, Olmstead MM, Mascharak PK. Synthesis, structure and properties of bis[N,N-bis(2-pyridylmethyl)amine-N-ethyl-2-pyridine-2-carboxamidecopper(II)] perchlorate. Inorganica Chim Acta 2002. [DOI: 10.1016/s0020-1693(01)00798-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Wada A, Ogo S, Nagatomo S, Kitagawa T, Watanabe Y, Jitsukawa K, Masuda H. Reactivity of hydroperoxide bound to a mononuclear non-heme iron site. Inorg Chem 2002; 41:616-8. [PMID: 11849054 DOI: 10.1021/ic001058h] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The first isolation and spectroscopic characterization of the mononuclear hydroperoxo-iron(III) complex [Fe(H(2)bppa)(OOH)](2+) (2) and the stoichiometric oxidation of substrates by the mononuclear iron-oxo intermediate generated by its decomposition have been described. The purple species 2 obtained from reaction of [Fe(H(2)bppa)(HCOO)](ClO(4))(2) with H(2)O(2) in acetone at -50 degrees C gave characteristic UV-vis (lambda(max) = 568 nm, epsilon = 1200 M(-1) cm(-1)), ESR (g = 7.54, 5.78, and 4.25, S = (5)/(2)), and ESI mass spectra (m/z 288.5 corresponding to the ion, [Fe(bppa)(OOH)](2+)), which revealed that 2 is a high-spin mononuclear iron(III) complex with a hydroperoxide in an end-on fashion. The resonance Raman spectrum of 2 in d(6)-acetone revealed two intense bands at 621 and 830 cm(-1), which shifted to 599 and 813 cm(-1), respectively, when reacted with (18)O-labeled H(2)O(2). Reactions of the isolated (bppa)Fe(III)-OOH (2) with various substrates (single turnover oxidations) exhibited that the iron-oxo intermediate generated by decomposition of 2 is a nucleophilic species formulated as [(H(2)bppa)Fe(III)-O*].
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Affiliation(s)
- Akira Wada
- Department of Applied Chemistry, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
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Rowland JM, Olmstead M, Mascharak PK. Syntheses, Structures, and Reactivity of Low Spin Iron(III) Complexes Containing a Single Carboxamido Nitrogen in a [FeN5L] Chromophore. Inorg Chem 2001; 40:2810-7. [PMID: 11375699 DOI: 10.1021/ic001127s] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new pentacoordinate ligand based on TPA (tris-(2-pyridylmethyl)amine), namely, N,N-bis(2-pyridylmethyl)amine-N-ethyl-2-pyridine-2-carboxamide (PaPy(3)H), has been synthesized. The iron(III) complexes of this ligand, namely, [Fe(PaPy(3))(CH(3)CN)](ClO(4))(2) (1), [Fe(PaPy(3))(Cl)]ClO(4) (2), [Fe(PaPy(3))(CN)]ClO(4) (3), and [Fe(PaPy(3))(N(3))]ClO(4) (4), have been isolated and complexes 1-3 have been structurally characterized. These complexes are the first examples of monomeric iron(III) complexes with one carboxamido nitrogen in the first coordination sphere. All four complexes are low spin and exhibit rhombic EPR signals around g = 2. The solvent bound species [Fe(PaPy(3))(CH(3)CN)](ClO(4))(2) reacts with H(2)O(2) in acetonitrile at low temperature to afford [Fe(PaPy(3))(OOH)](+) (g = 2.24, 2.14, 1.96). When cyclohexene is allowed to react with 1/H(2)O(2) at room temperature, a significant amount of cyclohexene oxide is produced along with the allylic oxidation products. Analysis of the oxidation products indicates that the allylic oxidation products arise from a radical-driven autoxidation process while the epoxidation is carried out by a distinctly different oxidant. No epoxidation of cyclohexene is observed with 1/TBHP.
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Affiliation(s)
- J M Rowland
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, USA
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Sobolev A, Babushkin D, Talsi E. Stability and reactivity of low-spin ferric hydroperoxo and alkylperoxo complexes with bipyridine and phenantroline ligands. ACTA ACUST UNITED AC 2000. [DOI: 10.1016/s1381-1169(00)00197-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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50
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Ohta T, Tachiyama T, Yoshizawa K, Yamabe T, Uchida T, Kitagawa T. Synthesis, structure, and H2O2-dependent catalytic functions of disulfide-bridged dicopper(I) and related thioether-copper(I) and thioether-copper(II) complexes. Inorg Chem 2000; 39:4358-69. [PMID: 11196933 DOI: 10.1021/ic000018a] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A disulfide-bridged dicopper(I) complex, [Cu2(Py2SSPy2)](ClO4)2 (1) (Py2SSPy2 = bis(2-[N,N-bis(2-pyridylethyl)-amino]-1,1- dimethylethyl)disulfide), a thioether-copper(I) complex, [Cu(iPrSPy2)](ClO4) (2) (iPrSPy2 = N-(2-isopropylthio-2-methyl)propyl-N,N-bis-2-(2-pyridyl)ethylamine, and a thioether-copper(II) complex, [Cu-(PheSPy2)(H2O)](ClO4)2 (3) (PheSPy2 = N-(2-methyl-2-phenethylthio)propyl-N,N-bis-2-(2- pyridyl)ethylamine), were newly synthesized by the reactions of Cu(ClO4)2.6H2O with a thiol ligand of Py2SH (N,N-bis[2-(2-pyridyl)-ethyl]-1,1-dimethyl-2- mercaptoethylamine) and thioether ligands of iPrSPy2 and PheSPy2, respectively. For complexes 1 and 2, X-ray analyses were performed. Complex 1 crystallizes in the triclinic space group P1, and complex 2 crystallizes in the orthorhombic space group Pbca with the following unit cell parameters: for 1, a = 15.165 (3) A, b = 22.185 (4) A, c = 14.989 (3) A, alpha = 105.76 (1) degrees, beta = 90.82 (2) degrees, gamma = 75.23 (1) degrees, and Z = 2; for 2, a = 17.78 (2) A, b = 17.70 (1) A, c = 15.75 (1) A, and Z = 8. Complex 1 is the first structurally characterized example obtained by the redox reaction Cu(II) + RSH-->Cu(I) + RSSR and has two independent structures (1a, 1b) which mainly differ in S-S bond distances, Cu(I)...Cu(I) separations, and C-S-S-C dihedral angles of the disulfide units. The S-S bond distances of 2.088(7) A in 1a and 2.070(7) A in 1b are indicative of significant activation of the S-S bonds by the dicopper centers. Fragment molecular orbital (FMO) analyses and molecular orbital overlap population (MOOP) analyses based on the extended Hückel method clarify the preferable formation of the disulfide S-S bond in 1 rather than the formation of a thiolate-copper(II) complex within the Py2S- ligand framework. Catalytic functions of complexes 1-3 were investigated with peroxides (H2O2 and tBuOOH) as oxidants. Complex 1 catalyzed the selective oxidation of cyclohexane to cyclohexanol and mediated the cyclohexene epoxidation in the presence of H2O2. A transient dark green intermediate observed in the reaction of 1 with H2O2 is characterized by UV-vis, EPR, and resonance Raman spectroscopies, identifying it as a Cu(II)-OOH species, 1(OOH). The resonance Raman features of the nu(O-O) bands at 822 and 836 cm-1, which are red-shifted to 781 and 791 cm-1, respectively, upon introduction of H2(18)O2, are indicative of formation of two kinds of Cu-OOH species rather than the Fermi doublet and the significant weakening of the O-O bonds. These mechanistic studies demonstrate that by virtue of the electron-donating ability of the disulfide unit the Cu-OOH species can be actually activated for one-electron oxidation, which has been reported so far unfavorable for other vibrationally characterized Cu-OOH species.
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Affiliation(s)
- T Ohta
- Department of Molecular Engineering, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
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