401
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Coordination compounds of Zn(II) with several bidentate-NN′ and tridentate-NN′N nitrogen donor ligands. Inorganica Chim Acta 2008. [DOI: 10.1016/j.ica.2008.02.059] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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402
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Singh AK, Jacob W, Boudalis AK, Tuchagues JP, Mukherjee R. A Tetragonal Core with Asymmetric Iron Environments Supported Solely by Bis(μ-OH){μ-(O–H···O)} Bridging and Terminal Pyridine Amide (N, O) Coordination: A New Member of the Tetrairon(III) Family. Eur J Inorg Chem 2008. [DOI: 10.1002/ejic.200800032] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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403
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de Visser S. Is the μ-Oxo-μ-Peroxodiiron Intermediate of a Ribonucleotide Reductase Biomimetic a Possible Oxidant of Epoxidation Reactions? Chemistry 2008; 14:4533-41. [DOI: 10.1002/chem.200701802] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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404
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Chatterjee PB, Mandal D, Audhya A, Choi KY, Endo A, Chaudhury M. Reporting a New Class of Divanadium(V) Compounds Connected by an Unsupported Hydroxo Bridge. Inorg Chem 2008; 47:3709-18. [DOI: 10.1021/ic702286h] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Pabitra Baran Chatterjee
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata 700 032, India, Department of Chemistry Education, Kongju National University, Kongju 314-701, South Korea, and Department of Chemistry, Faculty of Science and Technology, Sophia University, 7-1, Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan
| | - Debdas Mandal
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata 700 032, India, Department of Chemistry Education, Kongju National University, Kongju 314-701, South Korea, and Department of Chemistry, Faculty of Science and Technology, Sophia University, 7-1, Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan
| | - Anandalok Audhya
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata 700 032, India, Department of Chemistry Education, Kongju National University, Kongju 314-701, South Korea, and Department of Chemistry, Faculty of Science and Technology, Sophia University, 7-1, Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan
| | - Ki-Young Choi
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata 700 032, India, Department of Chemistry Education, Kongju National University, Kongju 314-701, South Korea, and Department of Chemistry, Faculty of Science and Technology, Sophia University, 7-1, Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan
| | - Akira Endo
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata 700 032, India, Department of Chemistry Education, Kongju National University, Kongju 314-701, South Korea, and Department of Chemistry, Faculty of Science and Technology, Sophia University, 7-1, Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan
| | - Muktimoy Chaudhury
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata 700 032, India, Department of Chemistry Education, Kongju National University, Kongju 314-701, South Korea, and Department of Chemistry, Faculty of Science and Technology, Sophia University, 7-1, Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan
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405
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Tejel C, Ciriano MA, del Río MP, van den Bruele FJ, Hetterscheid DGH, Tsichlis i Spithas N, de Bruin B. Deprotonation Induced Ligand-to-Metal Electron Transfer: Synthesis of a Mixed-Valence Rh(−I,I) Dinuclear Compound and Its Reaction with Dioxygen. J Am Chem Soc 2008; 130:5844-5. [DOI: 10.1021/ja711495v] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Cristina Tejel
- Departamento de Química Inorgánica, Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, E-50009 Zaragoza, Spain, and Homogeneous and Supramolecular Catalysis, Vanʼt Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - Miguel A. Ciriano
- Departamento de Química Inorgánica, Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, E-50009 Zaragoza, Spain, and Homogeneous and Supramolecular Catalysis, Vanʼt Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - M. Pilar del Río
- Departamento de Química Inorgánica, Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, E-50009 Zaragoza, Spain, and Homogeneous and Supramolecular Catalysis, Vanʼt Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - Fieke J. van den Bruele
- Departamento de Química Inorgánica, Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, E-50009 Zaragoza, Spain, and Homogeneous and Supramolecular Catalysis, Vanʼt Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - Dennis G. H. Hetterscheid
- Departamento de Química Inorgánica, Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, E-50009 Zaragoza, Spain, and Homogeneous and Supramolecular Catalysis, Vanʼt Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - Nearchos Tsichlis i Spithas
- Departamento de Química Inorgánica, Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, E-50009 Zaragoza, Spain, and Homogeneous and Supramolecular Catalysis, Vanʼt Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - Bas de Bruin
- Departamento de Química Inorgánica, Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza, Pedro Cerbuna 12, E-50009 Zaragoza, Spain, and Homogeneous and Supramolecular Catalysis, Vanʼt Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
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406
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Konar S, Clearfield A. Synthesis and Characterization of High Nuclearity Iron(III) Phosphonate Molecular Clusters. Inorg Chem 2008; 47:5573-9. [DOI: 10.1021/ic702453g] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sanjit Konar
- Department of Chemistry, Texas A&M University, College Station, Texas 77843
| | - Abraham Clearfield
- Department of Chemistry, Texas A&M University, College Station, Texas 77843
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407
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Aromatic hydroxylation by molecular oxygen performed by mononuclear benzoato iron(II) complexes and preparation of new iron(III) complex with two minus ligand. INORG CHEM COMMUN 2008. [DOI: 10.1016/j.inoche.2007.12.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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408
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Kastrup CJ, Runyon MK, Lucchetta EM, Price JM, Ismagilov RF. Using chemistry and microfluidics to understand the spatial dynamics of complex biological networks. Acc Chem Res 2008; 41:549-58. [PMID: 18217723 DOI: 10.1021/ar700174g] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Understanding the spatial dynamics of biochemical networks is both fundamentally important for understanding life at the systems level and also has practical implications for medicine, engineering, biology, and chemistry. Studies at the level of individual reactions provide essential information about the function, interactions, and localization of individual molecular species and reactions in a network. However, analyzing the spatial dynamics of complex biochemical networks at this level is difficult. Biochemical networks are nonequilibrium systems containing dozens to hundreds of reactions with nonlinear and time-dependent interactions, and these interactions are influenced by diffusion, flow, and the relative values of state-dependent kinetic parameters. To achieve an overall understanding of the spatial dynamics of a network and the global mechanisms that drive its function, networks must be analyzed as a whole, where all of the components and influential parameters of a network are simultaneously considered. Here, we describe chemical concepts and microfluidic tools developed for network-level investigations of the spatial dynamics of these networks. Modular approaches can be used to simplify these networks by separating them into modules, and simple experimental or computational models can be created by replacing each module with a single reaction. Microfluidics can be used to implement these models as well as to analyze and perturb the complex network itself with spatial control on the micrometer scale. We also describe the application of these network-level approaches to elucidate the mechanisms governing the spatial dynamics of two networkshemostasis (blood clotting) and early patterning of the Drosophila embryo. To investigate the dynamics of the complex network of hemostasis, we simplified the network by using a modular mechanism and created a chemical model based on this mechanism by using microfluidics. Then, we used the mechanism and the model to predict the dynamics of initiation and propagation of blood clotting and tested these predictions with human blood plasma by using microfluidics. We discovered that both initiation and propagation of clotting are regulated by a threshold response to the concentration of activators of clotting, and that clotting is sensitive to the spatial localization of stimuli. To understand the dynamics of patterning of the Drosophila embryo, we used microfluidics to perturb the environment around a developing embryo and observe the effects of this perturbation on the expression of Hunchback, a protein whose localization is essential to proper development. We found that the mechanism that is responsible for Hunchback positioning is asymmetric, time-dependent, and more complex than previously proposed by studies of individual reactions. Overall, these approaches provide strategies for simplifying, modeling, and probing complex networks without sacrificing the functionality of the network. Such network-level strategies may be most useful for understanding systems with nonlinear interactions where spatial dynamics is essential for function. In addition, microfluidics provides an opportunity to investigate the mechanisms responsible for robust functioning of complex networks. By creating nonideal, stressful, and perturbed environments, microfluidic experiments could reveal the function of pathways thought to be nonessential under ideal conditions.
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Affiliation(s)
- Christian J. Kastrup
- Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637
| | - Matthew K. Runyon
- Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637
| | - Elena M. Lucchetta
- Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637
| | - Jessica M. Price
- Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637
| | - Rustem F. Ismagilov
- Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637
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409
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410
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Pichon C, Dolbecq A, Mialane P, Marrot J, Rivière E, Goral M, Zynek M, McCormac T, Borshch S, Zueva E, Sécheresse F. Fe2 and Fe4 Clusters Encapsulated in Vacant Polyoxotungstates: Hydrothermal Synthesis, Magnetic and Electrochemical Properties, and DFT Calculations. Chemistry 2008; 14:3189-99. [DOI: 10.1002/chem.200700896] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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411
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Trovitch RJ, Lobkovsky E, Bill E, Chirik PJ. Functional Group Tolerance and Substrate Scope in Bis(imino)pyridine Iron Catalyzed Alkene Hydrogenation. Organometallics 2008. [DOI: 10.1021/om701091z] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ryan J. Trovitch
- Max-Planck Institute of Bioinorganic Chemistry, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany, and Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853
| | - Emil Lobkovsky
- Max-Planck Institute of Bioinorganic Chemistry, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany, and Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853
| | - Eckhard Bill
- Max-Planck Institute of Bioinorganic Chemistry, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany, and Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853
| | - Paul J. Chirik
- Max-Planck Institute of Bioinorganic Chemistry, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany, and Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853
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412
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Zhao M, Helms B, Slonkina E, Friedle S, Lee D, Dubois J, Hedman B, Hodgson KO, Fréchet JMJ, Lippard SJ. Iron complexes of dendrimer-appended carboxylates for activating dioxygen and oxidizing hydrocarbons. J Am Chem Soc 2008; 130:4352-63. [PMID: 18331028 DOI: 10.1021/ja076817a] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The active sites of metalloenzymes are often deeply buried inside a hydrophobic protein sheath, which protects them from undesirable hydrolysis and polymerization reactions, allowing them to achieve their normal functions. In order to mimic the hydrophobic environment of the active sites in bacterial monooxygenases, diiron(II) compounds of the general formula [Fe2([G-3]COO)4(4-RPy)2] were prepared, where [G-3]COO- is a third-generation dendrimer-appended terphenyl carboxylate ligand and 4-RPy is a pyridine derivative. The dendrimer environment provides excellent protection for the diiron center, reducing its reactivity toward dioxygen by about 300-fold compared with analogous complexes of terphenyl carboxylate ([G-1]COO-) ligands. An FeIIFeIII intermediate was characterized by electronic, electron paramagnetic resonance, Mössbauer, and X-ray absorption spectroscopic analyses following the oxygenation of [Fe2([G-3]COO)4(4-PPy)2], where 4-PPy is 4-pyrrolidinopyridine. The results are consistent with the formation of a superoxo species. This diiron compound, in the presence of dioxygen, can oxidize external substrates.
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Affiliation(s)
- Min Zhao
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
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413
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York JT, Bar-Nahum I, Tolman WB. Copper-Sulfur Complexes Supported by N-Donor Ligands: Towards Models of the Cu(Z) Site in Nitrous Oxide Reductase. Inorganica Chim Acta 2008; 361:885-893. [PMID: 19262681 PMCID: PMC2390864 DOI: 10.1016/j.ica.2007.06.047] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The distinctive structure of the [(his)(7)Cu(4)(μ-S)](n+) cluster in the "Cu(Z)" active site of nitrous oxide reductase and the intriguing mechanistic hypotheses for its catalytic reactivity provide inspiration for synthetic model studies aimed at characterizing relevant copper-sulfur compounds and obtaining fundamental insights into structure and bonding. In this brief review, we summarize such studies that have focused on the synthesis and characterization of a range of copper-sulfur complexes supported by N-donor ligands. Compounds with variable nuclearities and sulfur redox levels have been isolated, with the nature of the species obtained being dependent on the supporting ligand, sulfur source, and the reaction conditions. Spectroscopic data and theoretical calculations, often performed with a view toward drawing comparisons to oxygen analogs, have provided insight into the nature of the copper-sulfur bonding interactions in the complexes.
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Affiliation(s)
- John T. York
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455, USA
| | - Itsik Bar-Nahum
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455, USA
| | - William B. Tolman
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant St. SE, Minneapolis, Minnesota 55455, USA
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414
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Fujii S, Tsueda C, Yamabe K, Nakajima K, Sakai H. Reaction of iron(III)–polyaminocarboxylate complexes with hydrogen peroxide: Correlation between ligand structure and reactivity. Inorganica Chim Acta 2008. [DOI: 10.1016/j.ica.2007.09.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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415
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Friese SJ, Kucera BE, Young VG, Que L, Tolman WB. Iron(II) complexes of sterically bulky alpha-ketocarboxylates. structural models for alpha-ketoacid-dependent nonheme iron halogenases. Inorg Chem 2008; 47:1324-31. [PMID: 18217706 DOI: 10.1021/ic701823y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Reaction of the sterically hindered alpha-ketocarboxylate 2,6-di(mesityl)benzoylformate (MesBF) with the iron(II) complexes LFeCl 2 [L = N, N, N', N'-tetramethylpropylenediamine (Me 4pda) or 6,6'-dimethyl-2,2'-bipyridine (dmby)] yielded LFe(Cl)(MesBF) ( 1 or 2). X-ray crystal structures of these complexes showed that they closely model the active site structure of the nonheme iron halogenase enzyme SyrB2. A similar synthetic procedure using benzoylformate with L = dmby yielded (dmby)Fe[(O 2CC(O)Ph)] 2 ( 3) instead, demonstrating the need for the sterically hindered alpha-ketocarboxylate to assemble the halogenase model compounds. In order to make reactivity comparisons among the structurally related iron(II) complexes of benzoylformates of varying steric properties, the complexes [LFe(O 2CC(O)Ar)] n ( 4- 6) were prepared, where L' = tris(pyridylmethyl)amine (tpa) and Ar = 2,6-dimesitylphenyl, 2,6-di p-tolylphenyl, or 2,4,6-trimethylphenyl, respectively. X-ray structures for the latter two cases ( 5 and 6) revealed dinuclear topologies ( n = 2), but UV-vis and (1)H NMR spectroscopy indicated that all three complexes dissociated in varying degrees to monomers in CH 2Cl 2 solution. Although compounds 1- 6 were oxidized by O 2, oxidative decarboxylation of the alpha-ketocarboxylate ligand(s) only occurred for 3. These results indicate that the steric hindrance useful for structural modeling of the halogenase active site prohibits functional mimicry of the enzyme.
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Affiliation(s)
- Seth J Friese
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant Street SE, Minneapolis, MN 55455, USA
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416
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Lin HW. Di-μ-thio-cyanato-κN:N-bis-({2,4-di-bromo-6-[2-(methyl-amino)ethyl-imino-meth-yl]-phenol-ato-κN,N',O}nickel(II)). Acta Crystallogr Sect E Struct Rep Online 2008; 64:m295. [PMID: 21201272 PMCID: PMC2960283 DOI: 10.1107/s1600536807068146] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2007] [Accepted: 12/21/2007] [Indexed: 11/10/2022]
Abstract
The title complex, [Ni(2)(C(11)H(11)Br(2)N(2)O)(2)(NCS)(2)], is a thio-cyanate-bridged dinuclear nickel(II) complex. The asymmetric unit contains two molecules. Both Ni atoms in each molecule have a square-pyramidal coordination geometry, and each center is bound by one O and two N atoms of one Schiff base ligand and by one N atom of a bridging thio-cyanate ligand, which define the basal planes. N atoms from the bridging thio-cyanate ligands occupy the apical positions.
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Affiliation(s)
- Hong-Wei Lin
- Department of Chemistry, Huaihua University, Huaihua 418008, People’s Republic of China
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417
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Reisner E, Lippard SJ. Synthesis of Dicarboxylate “C-Clamp” 1,2-Diethynylarene Compounds as Potential Transition-Metal Ion Hosts. European J Org Chem 2008. [DOI: 10.1002/ejoc.200700816] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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418
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Sorokin AB, Kudrik EV, Bouchu D. Bio-inspired oxidation of methane in water catalyzed by N-bridged diiron phthalocyanine complex. Chem Commun (Camb) 2008:2562-4. [DOI: 10.1039/b804405h] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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419
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Binning RC, Bacelo DE. High-spin versus broken symmetry—Effect of DFT spin density representation on the geometries of three diiron (III) model compounds. J Comput Chem 2008; 29:716-23. [PMID: 17849393 DOI: 10.1002/jcc.20833] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Unrestricted density functional theory calculations have been conducted on three diiron(III) synthetic model compounds containing antiferromagnetically coupled high-spin (HS) irons for which crystallographic structures and Raman spectral data are available. Three density functionals have been employed: BPW91, PWC, and BOP. The study compares the effects on optimized geometries and harmonic vibrational frequencies of spin-paired (SP) low-spin, HS, and broken symmetry antiferromagnetically coupled singlet representations of the spin density distribution. The geometries around the diiron centers in the HS and broken symmetry (BS) representations are found to be similar, both markedly different from those arising from the SP representation. Small differences between the HS and BS results are seen in bond lengths, angles, Raman frequencies, and spin densities associated with oxo and peroxo bridges between the irons.
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Affiliation(s)
- R C Binning
- Department of Sciences and Technology, Universidad Metropolitana, P. O. Box 21150, San Juan, Puerto Rico 00928-1150, USA.
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420
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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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421
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Moon D, Kim J, Oh M, Suh BJ, Lah MS. Synthesis and characterization of a bis-μ,η1-carboxylate-bridged dinuclear manganese(II) complex containing a tetradentate tripodal ligand, N-(benzimidazol-2-ylmethyl)iminodiacetic acid. Polyhedron 2008. [DOI: 10.1016/j.poly.2007.09.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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422
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Bruijnincx PCA, van Koten G, Klein Gebbink RJM. Mononuclear non-heme iron enzymes with the 2-His-1-carboxylate facial triad: recent developments in enzymology and modeling studies. Chem Soc Rev 2008; 37:2716-44. [DOI: 10.1039/b707179p] [Citation(s) in RCA: 412] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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423
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Synthetic iron-oxo "diamond core" mimics structure of key intermediate in methane monooxygenase catalytic cycle. Proc Natl Acad Sci U S A 2007; 104:20641-2. [PMID: 18093936 DOI: 10.1073/pnas.0710734105] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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424
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Chen MS, White MC. A predictably selective aliphatic C-H oxidation reaction for complex molecule synthesis. Science 2007; 318:783-7. [PMID: 17975062 DOI: 10.1126/science.1148597] [Citation(s) in RCA: 1003] [Impact Index Per Article: 59.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Realizing the extraordinary potential of unactivated sp3 C-H bond oxidation in organic synthesis requires the discovery of catalysts that are both highly reactive and predictably selective. We report an iron (Fe)-based small molecule catalyst that uses hydrogen peroxide (H2O2) to oxidize a broad range of substrates. Predictable selectivity is achieved solely on the basis of the electronic and steric properties of the C-H bonds, without the need for directing groups. Additionally, carboxylate directing groups may be used to furnish five-membered ring lactone products. We demonstrate that these three modes of selectivity enable the predictable oxidation of complex natural products and their derivatives at specific C-H bonds with preparatively useful yields. This type of general and predictable reactivity stands to enable aliphatic C-H oxidation as a method for streamlining complex molecule synthesis.
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Affiliation(s)
- Mark S Chen
- Department of Chemistry, Roger Adams Laboratory, University of Illinois, Urbana, IL 61801, USA
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425
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Reisner E, Telser J, Lippard SJ. A Planar Carboxylate-Rich Tetrairon(II) Complex and Its Conversion to Linear Triiron(II) and Paddlewheel Diiron(II) Complexes. Inorg Chem 2007; 46:10754-70. [DOI: 10.1021/ic701663j] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Erwin Reisner
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, and Department of Biological, Chemical, and Physical Sciences, Roosevelt University, 430 S. Michigan Avenue, Chicago, Illinois 60605
| | - Joshua Telser
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, and Department of Biological, Chemical, and Physical Sciences, Roosevelt University, 430 S. Michigan Avenue, Chicago, Illinois 60605
| | - Stephen J. Lippard
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, and Department of Biological, Chemical, and Physical Sciences, Roosevelt University, 430 S. Michigan Avenue, Chicago, Illinois 60605
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426
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Rowe GT, Rybak-Akimova EV, Caradonna JP. Unraveling the reactive species of a functional non-heme iron monooxygenase model using stopped-flow UV-vis spectroscopy. Inorg Chem 2007; 46:10594-606. [PMID: 17988120 DOI: 10.1021/ic7011217] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Low-temperature stopped-flow electronic spectroscopy was utilized to resolve the intermediates formed in the reaction of a diiron(II) compound, Fe2(H2Hbamb)2(N-MeIm)2 (H4HBamb = 2,3-bis(2-hydroxybenzamido)dimethylbutane), 1, with the oxygen atom donors 2,6-dimethyliodosylbenzene and p-cyanodimethylaniline N-oxide and the mechanistic probe hydroperoxide 2-methyl-1-phenylprop-2-yl hydroperoxide (MPPH). Previous studies showed that 1 is capable of catalytically oxidizing cyclohexane to cyclohexanol (300 turnovers) via a pathway involving the heterolytic cleavage of the O-O bond of MPPH (>98% peroxide utilization). We now report intimate details of the formation of the reactive intermediate and its subsequent decay in the absence of substrates. The reaction, which is independent of the nature of the oxidant, proceeds in three consecutive steps assigned as (i) oxygen-atom transfer to one of the iron centers of 1 to form an FeIV=O species, 2, (ii) ligand rearrangement to 3, and (iii) internal collapse of the terminal oxo group to generate a diferric, mu-oxo species, 4. Assignment of the second step as a ligand rearrangement was corroborated by stopped-flow spectroscopic studies of the one-electron oxidation of the starting diferrous 1, which is also known to undergo ligand rearrangement upon the formation of the [FeII, FeIII] mixed-valent complex. Observation of the reaction rates over a temperature range allowed for the determination of activation parameters for each of the three steps. The role of the ligand reorganization in the energetic profile for the formation of the catalytically competent intermediate is discussed, along with the potential biological significance of the internal conversion of the active oxidant to the inert, mu-oxo diiron(III) dimer, 4.
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Affiliation(s)
- Gerard T Rowe
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, USA
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427
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Guillemot G, Neuburger M, Pfaltz A. Synthesis and Metal Complexes of ChiralC2-Symmetric Diamino–Bisoxazoline Ligands. Chemistry 2007; 13:8960-70. [PMID: 17721893 DOI: 10.1002/chem.200700826] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A synthetic route to tetradentate chiral N(4) ligands has been developed with the aim to study the potential of corresponding iron and manganese complexes as catalysts for enantioselective epoxidation. These ligands, which contain two oxazoline rings and two trialkylamino groups as coordinating units, are readily prepared in enantiomerically pure form by the reaction of chiral 2-chloromethyloxazolines with achiral N,N'-dimethylethane-1,2-diamine or chiral (R,R)-N,N'-dimethylcyclohexane-1,2-diamine. The ligands derived from N,N'-dimethylethane-1,2-diamine reacted with anhydrous metal halides MnCl(2) and FeCl(2) in a stereoselective manner to give octahedral mononuclear complexes that have the general formula Delta-[(L)MCl(2)]. In contrast, the ligands derived from N,N'-dimethylcyclohexane-1,2-diamine formed complexes with different coordination modes depending on the diastereomer employed: in one case the metal ion was found to be pentacoordinate, in the other case a hexacoordinated complex was observed. The structure of a series of Fe and Mn complexes was determined by X-ray analysis. The coordination chemistry of these ligands was further studied by X-ray and NMR analyses of the diamagnetic isostructural complexes [(L)ZnCl(2)]. Analogous ionic complexes, which were prepared by removing chloride with silver trifluoromethanesulfonate or hexafluoroantimonate, were tested as catalysts for the epoxidation of olefins.
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Affiliation(s)
- Geoffroy Guillemot
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
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428
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Reisner E, Abikoff TC, Lippard SJ. Influence of Steric Hindrance on the Core Geometry and Sulfoxidation Chemistry of Carboxylate-Rich Diiron(II) Complexes. Inorg Chem 2007; 46:10229-40. [DOI: 10.1021/ic7014176] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Erwin Reisner
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Tanya C. Abikoff
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Stephen J. Lippard
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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429
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Long J, Wang X, Zhang G, Dong J, Yan T, Li Z, Fu X. A Mononuclear Cyclopentadiene–Iron Complex Grafted in the Supercages of HY Zeolite: Synthesis, Structure, and Reactivity. Chemistry 2007; 13:7890-9. [PMID: 17611950 DOI: 10.1002/chem.200700505] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The reaction of ferrocene with the acidic hydroxy groups in the supercages of zeolite HY dehydrated at 673 K and the reactivity of the resultant surface species towards CO and O(2) were investigated by temperature-programmed decomposition (TPD) and reduction (TPR) and IR, X-ray absorption fine structure analysis (XAFS), and X-ray photoelectron (XP) spectroscopy. In situ FTIR, TPD, TPR, and chemical analysis reveal that the Cp(2)Fe molecule adsorbed on the zeolite surface loses one cyclopentadienyl group under vacuum at 423 K, which leads to the formation of a well-defined mononuclear surface Fe-C(5)H(6) complex grafted to two acidic sites and one ([triple bond]Si-O-Si[triple bond]) unit, as confirmed by the lack of Fe-Fe contributions in the EXAFS spectra. Each iron atom is coordinated, on average, to three oxygen atoms of the zeolite surface with a Fe--O distance of 2.00 A and to five carbon atoms with a Fe--C distance of 2.09 A. IR spectra indicate that the cyclopentadiene-iron species grafted on the surface of the zeolite is quite stable in vacuo or under an inert or hydrogen atmosphere below 423 K, and is also relatively stable under oxygen at room temperature. However, the cyclopentadiene ligand readily reacts with CO to form a compound containing carbonyl at 323 K, and even at room temperature. The single carbonyl band in the IR spectra provides evidence for the nearly uniform formation of a cyclopentadiene-iron species on the surface of the zeolite.
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Affiliation(s)
- Jinlin Long
- Research Institute of Photocatalysis, State Key Laboratory Breeding Base of Photocatalysis, Fuzhou University, Fuzhou, 350002, China
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430
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Duban EA, Drebushchak TN, Bryliakov KP, Talsi EP. X-ray crystal structure of [BPMEN(Cl)FeIIIOFeIII(Cl)BPMEN](ClO4)2 [BPMEN = N,N’-dimethyl-N,N’-bis(2-pyridylmethyl)ethane-1,2-diamine] and the assignment of its 1H NMR peaks in CD3CN. MENDELEEV COMMUNICATIONS 2007. [DOI: 10.1016/j.mencom.2007.09.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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431
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Dennis AE, Smith RC. "Turn-on" fluorescent sensor for the selective detection of zinc ion by a sterically-encumbered bipyridyl-based receptor. Chem Commun (Camb) 2007:4641-3. [PMID: 17989818 DOI: 10.1039/b710740d] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A sterically-encumbered 5,5'-distyryl-2,2'-bipyridyl derivative that enforces a 1:1 metal-to-ligand ratio acts as a selective turn-on sensor for Zn(2+) in THF.
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Affiliation(s)
- Ashlyn E Dennis
- Department of Chemistry and Center for Optical Materials Science and Engineering Technologies (COMSET), Clemson University, Clemson, SC 29634, USA
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432
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Maglio O, Nastri F, Martin de Rosales RT, Faiella M, Pavone V, DeGrado WF, Lombardi A. Diiron-containing metalloproteins: Developing functional models. CR CHIM 2007. [DOI: 10.1016/j.crci.2007.03.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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433
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Korendovych IV, Kryatov SV, Rybak-Akimova EV. Dioxygen activation at non-heme iron: insights from rapid kinetic studies. Acc Chem Res 2007; 40:510-21. [PMID: 17521158 DOI: 10.1021/ar600041x] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
One of the common biochemical pathways of binding and activation of dioxygen involves non-heme iron centers. The enzyme cycles usually start with an iron(II) or diiron(II) state and traverse via several intermediates (detected or postulated) such as (di)iron(III)-superoxo, (di)iron(III)-(hydro)peroxo, iron(III)iron(IV)-oxo, and (di)iron(IV)-oxo species, some of which are responsible for substrate oxidation. In this Account, we present results of kinetic and mechanistic studies of dioxygen binding and activation reactions of model inorganic iron compounds. The number of iron centers, their coordination number, and the steric and electronic properties of the ligands were varied in several series of well-characterized complexes that provided reactive manifolds modeling the function of native non-heme iron enzymes. Time-resolved cryogenic stopped-flow spectrophotometry permitted the identification of kinetically competent intermediates in these systems. Inner-sphere mechanisms dominated the chemistry of dioxygen binding, intermediate transformations, and substrate oxidation as most of these processes were controlled by the rates of ligand substitution at the iron centers.
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Affiliation(s)
- Ivan V Korendovych
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, USA
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434
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Nam W. High-valent iron(IV)-oxo complexes of heme and non-heme ligands in oxygenation reactions. Acc Chem Res 2007; 40:522-31. [PMID: 17469792 DOI: 10.1021/ar700027f] [Citation(s) in RCA: 909] [Impact Index Per Article: 53.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
High-valent iron(IV)-oxo species have been implicated as the key reactive intermediates in the catalytic cycles of dioxygen activation by heme and non-heme iron enzymes. Our understanding of the enzymatic reactions has improved greatly via investigation of spectroscopic and chemical properties of heme and non-heme iron(IV)-oxo complexes. In this Account, reactivities of synthetic iron(IV)-oxo porphyrin pi-cation radicals and mononuclear non-heme iron(IV)-oxo complexes in oxygenation reactions have been discussed as chemical models of cytochrome P450 and non-heme iron enzymes. These results demonstrate how mechanistic developments in biomimetic research can help our understanding of dioxygen activation and oxygen atom transfer reactions in nature.
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Affiliation(s)
- Wonwoo Nam
- Department of Chemistry, Division of Nano Sciences, and Center for Biomimetic Systems, Ewha Womans University, Seoul 120-750, Korea.
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435
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Suzuki M. Ligand effects on dioxygen activation by copper and nickel complexes: reactivity and intermediates. Acc Chem Res 2007; 40:609-17. [PMID: 17559187 DOI: 10.1021/ar600048g] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Copper and nickel complexes having various active-oxygen species M n -O 2 ( n = 1 or 2), such as trans-(micro-1,2-peroxo)Cu (II) 2, bis(micro-oxo)M (III) 2, bis(micro-superoxo)Ni (II) 2, and ligand-based alkylperoxo-M (II) n , can be produced by a series of tetradentate tripodal ligands (TMPA analogues) containing sterically demanding 6-methyl substituent(s) on the pyridyl group(s), where TMPA = tris(2-pyridylmethyl)amine. Roles of the methyl substituent(s) for the formation of the active-oxygen species and their oxidation reactivities are reported.
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Affiliation(s)
- Masatatsu Suzuki
- Department of Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.
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436
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Kim Y, Feng X, Lippard SJ. Synthesis, structure, and properties of a mixed-valent triiron complex of tetramethyl reductic acid, an ascorbic acid analogue, and its relationship to a functional non-heme iron oxidation catalyst system. Inorg Chem 2007; 46:6099-107. [PMID: 17579400 PMCID: PMC3236675 DOI: 10.1021/ic700622a] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The purple triiron(II,III,III) complex, [Fe(3)Cl(2)(TMRASQ)(4)(HTMRA)(2)] x C(5)H(12) (1 x C(5)H(12)), where H(2)TMRA is a tetramethyl reductic acid, 4,4,5,5-tetramethyl-2,3-dihydroxy-2-cyclopenten-1-one, and HTMRASQ is the semiquinone form of this ligand, was prepared from (Et(4)N)(2)[Fe(2)OCl(6)] and H(2)TMRA and characterized by X-ray crystallography, Mössbauer spectroscopy, and redox titrations. The physical properties of the complex in solution are consistent with its mixed-valent character, as delineated by a solid-state structure analysis. Assignments of the iron and ligand oxidation states in the crystal were made on the basis of a valence bond sum analysis and the internal ligand geometry. As the first well-characterized iron complex of an ascorbic acid H(2)AA analogue, 1 provides insight into the possible coordination geometry of the family of complexes containing H(2)AA and its analogues. In the presence of air and H(2)TMRA, 1 is able to catalyze the oxidation of cyclohexane to cyclohexanol with remarkable selectivity, but the nature of the true catalyst remains unknown.
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437
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Collman JP, Yan YL, Lei J, Dinolfo PH. Active-site models of bacterial nitric oxide reductase featuring tris-histidyl and glutamic acid mimics: influence of a carboxylate ligand on Fe(B) binding and the heme Fe/Fe(B) redox potential. Inorg Chem 2007; 45:7581-3. [PMID: 16961346 PMCID: PMC2593900 DOI: 10.1021/ic0609150] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Active-site models of bacterial nitric oxide reductase (NOR) featuring a heme Fe and a trisimidazole- and glutaric acid-bound non-heme Fe (Fe(B)) have been synthesized. These models closely replicate the proposed active site of native NORs. Examination of these models shows that the glutamic acid mimic is required for both Fe(B) retention in the distal binding site and proper modulation of the redox potentials of both the heme and non-heme Fe's.
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Affiliation(s)
- James P Collman
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA.
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438
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Boudalis AK, Sanakis Y, Clemente-Juan JM, Mari A, Tuchagues JP. A Diferrous Single-Molecule Magnet. Eur J Inorg Chem 2007. [DOI: 10.1002/ejic.200700203] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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439
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Wade H, Stayrook SE, Degrado WF. The structure of a designed diiron(III) protein: implications for cofactor stabilization and catalysis. Angew Chem Int Ed Engl 2007; 45:4951-4. [PMID: 16819737 DOI: 10.1002/anie.200600042] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Herschel Wade
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104, USA
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440
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Pacześniak T, Błoniarz P, Rydel K, Sobkowiak A. Electrochemical Catalytic Processes with Hydrogen Peroxide Showing Oxidative and Reductive Properties (Acting as Oxidant or Reductant). ELECTROANAL 2007. [DOI: 10.1002/elan.200603819] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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441
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Givaja G, Volpe M, Leeland JW, Edwards MA, Young TK, Darby SB, Reid SD, Blake AJ, Wilson C, Wolowska J, McInnes EJL, Schröder M, Love JB. Design and Synthesis of Binucleating Macrocyclic Clefts Derived from Schiff-Base Calixpyrroles. Chemistry 2007; 13:3707-23. [PMID: 17245783 DOI: 10.1002/chem.200600989] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The syntheses, characterisation and complexation reactions of a series of binucleating Schiff-base calixpyrrole macrocycles are described. The acid-templated [2+2] condensations between meso-disubstituted diformyldipyrromethanes and o-phenylenediamines generate the Schiff-base pyrrolic macrocycles H(4)L(1) to H(4)L(6) upon basic workup. The single-crystal X-ray structures of both H(4)L(3).2 EtOH and H(4)L(6).H2O confirm that [2+2] cyclisation has occurred, with either EtOH or H2O hydrogen-bonded within the macrocyclic cleft. A series of complexation reactions generate the dipalladium [Pd2(L)] (L=L(1) to L(5)), dinickel [Ni2(L(1))] and dicopper [Cu2(L)] (L=L(1) to L(3)) complexes. All of these complexes have been structurally characterised in the solid state and are found to adopt wedged structures that are enforced by the rigidity of the aryl backbone to give a cleft reminiscent of the structures of Pacman porphyrins. The binuclear nickel complexes [Ni2(mu-OMe)2Cl2(HOMe)2(H(4)L(1))] and [Ni2(mu-OH)2Cl2(HOMe)(H(4)L(5))] have also been prepared, although in these cases the solid-state structures show that the macrocyclic ligand remains protonated at the pyrrolic nitrogen atoms, and the Ni(II) cations are therefore co-ordinated by the imine nitrogen atoms only to give an open conformation for the complex. The dicopper complex [Cu2(L(3))] was crystallised in the presence of pyridine to form the adduct [Cu2(py)(L(3))], in which, in the solid state, the pyridine ligand is bound within the binuclear molecular cleft. Reaction between H(4)L(1) and [Mn(thf){N(SiMe(3))2}2] results in clean formation of the dimanganese complex [Mn2(L(1))], which, upon crystallisation, formed the mixed-valent complex [Mn2(mu-OH)(L(1))] in which the hydroxo ligand bridges the metal centres within the molecular cleft.
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Affiliation(s)
- Gonzalo Givaja
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
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442
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Kodera M, Kano K. Reversible O2-Binding and Activation with Dicopper and Diiron Complexes Stabilized by Various Hexapyridine Ligands. Stability, Modulation, and Flexibility of the Dinuclear Structure as Key Aspects for the Dimetal/O2Chemistry. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2007. [DOI: 10.1246/bcsj.80.662] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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443
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444
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Min KS, Arif AM, Miller JS. Synthesis, structure and magnetic properties of an oxo-bridged dinuclear iron(III) complex [(TPyA)FFeIIIOFeIIIF(TPyA)](BF4)2·0.5MeOH (TPyA=tris(2-pyridylmethyl)amine) containing the FFeIIIOFeIIIF linkage. Inorganica Chim Acta 2007. [DOI: 10.1016/j.ica.2006.09.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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445
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Kamata K, Kuzuya S, Uehara K, Yamaguchi S, Mizuno N. μ-η1:η1-Peroxo-Bridged Dinuclear Peroxotungstate Catalytically Active for Epoxidation of Olefins. Inorg Chem 2007; 46:3768-74. [PMID: 17375917 DOI: 10.1021/ic0701211] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reaction of the dinuclear peroxotungstate, [(n-C4H9)4N]2[{WO(O2)2}2(mu-O)] (II), with H2O2 gives the novel mu-eta1:eta1-peroxo-bridging dinuclear tungsten species, [(n-C4H9)4N]2[{WO(O2)2}2(mu-O2)] (I), which has been characterized by X-ray crystallography, elemental analysis, IR, Raman, UV-vis, and 183W NMR. Only I is active for the epoxidation of cyclic, internal, and terminal olefins, whereas II is inactive for each. The low XSO (XSO=(nucleophilic oxidation)/(total oxidation)) value of I (0.18+/-0.02) in comparison with that of II (0.39+/-0.01) for the stoichiometric oxidation of thianthrene 5-oxide, which is a mechanistic probe for determining the electronic character of an oxidant, reveals that I is more electrophilic than II. On the basis of the kinetic and spectroscopic results, the catalytic epoxidation proceeds by the reaction of I with an olefin to form II and the corresponding epoxide followed by the regeneration of I by the reaction of II with H2O2.
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Affiliation(s)
- Keigo Kamata
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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446
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Bacelo DE, Binning RC. Computational study of iron(II) and -(III) complexes with a simple model human H ferritin ferroxidase center. Inorg Chem 2007; 45:10263-9. [PMID: 17140234 DOI: 10.1021/ic060388k] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Interaction of iron ions with a six-amino acid model of the ferroxidase center of human H chain ferritin has been examined in density functional theory calculations. The model, based on experimental studies of oxidation of Fe2+ at the center, consists of Glu27, Glu62, His65, Glu107, Gln141, and Ala144. Reasonable structures are obtained in a survey of types of iron complexes inferred to occur in the ferroxidase reaction. Structures of complexes of the model center with one and two Fe2+ ions, with diiron(III) bridged by peroxide and bridged by oxide-peroxide combinations, have been optimized. Calculations on diiron(III) complexes confirm that stable peroxide-bridged complexes can form and that the Fe-Fe distance in at least one is consistent with the experimental Fe-Fe distance observed in the blue peroxodiferric complex of ferritin.
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Affiliation(s)
- Daniel E Bacelo
- Department of Sciences and Technology, Universidad Metropolitana, San Juan, Puerto Rico 00928-1150
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447
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Min KS, DiPasquale AG, Golen JA, Rheingold AL, Arif AM, Miller JS. Synthesis, structure, and magnetic properties of valence ambiguous dinuclear antiferromagnetically coupled cobalt and ferromagnetically coupled iron complexes containing the chloranilate(2-) and the significantly stronger coupling chloranilate(*3-) radical trianion. J Am Chem Soc 2007; 129:2360-8. [PMID: 17269771 DOI: 10.1021/ja067208q] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dinuclear [(TPyA)MII(CA2-)MII(TPyA)]2+ [TPyA=tris(2-pyridylmethyl)amine; CA2-=chloranilate dianion; M=Co (1(2+)), Fe (2(2+))] complexes have been prepared by the reaction of M(BF4)(2).6H2O, TPyA, H2CA, and triethylamine in MeOH solution. Their reduced forms [(TPyA)MII(CA*3-)MII(TPyA)]+ [M=Co(1+), Fe (2+)] have been synthesized by using cobaltocene, and oxidized forms of 1, [(TPyA)CoIII(CAn)CoIII(TPyA)]z+ [z=3, n=3- (1(3+)); z=4, n=2- (1(4+))], have been obtained by using FcBF4 and ThianBF4 (Fc=ferrocenium; Thian=thianthrinium), respectively. The dinuclear compound bridged chloranilates (CA2- or CA*3-) were isolated and characterized by X-ray crystallography, electrochemistry, magnetism, and EPR spectroscopy. Unlike the other redox products, valence ambiguous 13+ forms via a complex redox-induced valence electron rearrangement whereby the one-electron oxidation of the [CoIICA2-CoII]2+ core forms [CoIIICA*3-CoIII]3+, not the expected simple 1-e- transfer mixed-valent [CoIICA2-CoIII]3+ core. The M ions in 1 and 2 have a distorted octahedral geometry by coordination with four nitrogens of a TPyA, two oxygens of a chloranilate. Due to the interdimer offset face-to-face pi-pi and/or herringbone interactions, all complexes show extended 1-D and/or 2-D supramolecular structures. The existence of CA*3- in 1(3+) is confirmed from both solid-state magnetic and solution EPR data. Co-based 1n+ exhibit antiferromagnetic interactions [1(2+): g=2.24, J/kB=-0.65 K (-0.45 cm-1); 1+: g=2.36, J/kB=-75 K (52 cm-1)], while Fe-based 2n+ exhibit ferromagnetic interactions [2(2+): g=2.08, J/kB=1.0 K (0.70 cm-1); 2+: g=2.03, J/kB=28 K (19 cm-1)] [H=-2JS1.S2 for 12+ and 2(2+); H=-2J(S1.S2+S2.S3) for 1+ and 2+]. Thus, due to direct spin exchange CA*3- is a much strong spin coupling linkage than the superexchange spin-coupling pathway provided by CA2-.
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Affiliation(s)
- Kil Sik Min
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112-0850, USA
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448
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Duban EA, Bryliakov KP, Talsi EP. The Active Intermediates of Non-Heme-Iron-Based Systems for Catalytic Alkene Epoxidation with H2O2/CH3COOH. Eur J Inorg Chem 2007. [DOI: 10.1002/ejic.200600895] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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