1
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Tołoczko A, Kaźmierczak M, Książek M, Weselski M, Siczek M, Kusz J, Bronisz R. Expanding the dimensionality of bis(tetrazolyl)alkane-based Fe(II) coordination polymers by the application of dinitrile coligands. Dalton Trans 2024; 53:7163-7174. [PMID: 38573306 DOI: 10.1039/d4dt00462k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2024]
Abstract
Reactions between 1,2-di(tetrazol-2-yl)ethane (ebtz), 1,6-di(tetrazol-2-yl)hexane (hbtz) or 1,1'-di(tetrazol-1-yl)methane (1ditz) and Fe(BF4)2 in the presence of adiponitrile (ADN), glutaronitrile (GLN) or suberonitrile (SUN) resulted in the formation of coordination polymers [Fe(μ-ebtz)2(μ-ADN)](BF4)2 (1), [Fe(μ-hbtz)2(μ-ADN)](BF4)2 (2), [Fe(μ-1ditz)2(GLN)2](BF4)2·GLN (3) and [Fe(μ-1ditz)2(μ-SUN)](BF4)2·SUN (4). It was established that the application of dinitriles allows an increase in the dimensionality of the ebtz and hbtz based systems while maintaining the structure of the polymeric units characteristic of previously studied mononitrile based analogues. In 3 and 4, regardless of the type of dinitrile coligand, the motif of 2D polymeric layers constituted by 1ditz molecules remains preserved. However, the dimensionality of 1ditz based networks is governed by the coordination modes of dinitriles. 3, based on a shorter molecule of glutaronitrile, crystallizes as a two-dimensional (2D) coordination polymer. In this compound, dinitriles coordinate monodentately or play the role of guest molecules. The substitution of glutaronitrile with suberonitrile enables the bridging of neighboring polymeric layers, resulting in a 3D network. The intentional selection of bis(tetrazoles) and dinitriles as building blocks has led, as expected, to obtaining systems with the structure of the first coordination sphere consisting of four tetrazole rings and two axially coordinated nitrile molecules. It created the conditions required for the occurrence of thermally induced spin crossover. Magnetic measurements and single crystal X-ray diffraction studies were used for the characterization of the spin crossover properties of 1-4.
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Affiliation(s)
- Aleksandra Tołoczko
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland.
| | - Marcin Kaźmierczak
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland.
| | - Maria Książek
- Institute of Physics, University of Silesia, 75 Pułku Piechoty 1, 41-500 Chorzów, Poland
| | - Marek Weselski
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland.
| | - Miłosz Siczek
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland.
| | - Joachim Kusz
- Institute of Physics, University of Silesia, 75 Pułku Piechoty 1, 41-500 Chorzów, Poland
| | - Robert Bronisz
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland.
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2
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Mitra M, Brinkmeier A, Li Y, Borrell M, Call A, Lloret Fillol J, Richmond MG, Costas M, Nordlander E. An investigation of steric influence on the reactivity of Fe V(O)(OH) tautomers in stereospecific C-H hydroxylation. Dalton Trans 2023; 52:3596-3609. [PMID: 36602022 DOI: 10.1039/d2dt00725h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Two new tetradentate N4 ligands (LN4), LN4 = Me2,Me2PyzTACN (1-(2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyl)-4,7-dimethyl-1,4,7-triazacyclononane) and Me2,MeImTACN (1-((1-methyl-1H-imidazol-1-yl)methyl)-4,7-dimethyl-1,4,7-triazacyclononane) have been synthesized and their corresponding Fe(II) complexes [FeII(Me2,Me2PyzTACN)(CF3SO3)2], 1Pz, and [FeII(Me2,MeImTACN)(CF3SO3)2], 1Im, have been prepared and characterized. Complexes 1Pz and 1Im catalyse the hydroxylation of C-H bonds of alkanes with excellent efficiencies, using hydrogen peroxide as oxidant. The high H/D kinetic isotope effect values for C-H hydroxylation, large normalized tertiary/secondary C-H (C3/C2) bond selectivities in adamantane oxidation, and high degrees of stereoretention in the oxidation of cis-1,2-dimethylcyclohexane are indicative of metal-based oxidation processes. The complexes also catalyse the oxidation of cyclooctene to form its corresponding epoxide and syn-diol. For 1Pz the epoxide is the main product, while for the analogous complex 1Im the syn-diol predominates. The active oxidant is proposed to be an [(LN4)FeV(O)(OH)]2+ species (2Pz, LN4 = Me2,Me2PyzTACN and 2Im, LN4 = Me2,MeImTACN) which may exist in two tautomeric forms related by a proton shift between the oxo and hydroxo ligands. Isotope labelling experiments show that the oxygen atom in the hydroxylated products originates from both water and hydrogen peroxide, and labelling experiments involving oxygen atom transfer to sterically bulky substrates provide indirect information on the steric influence exerted by the two ligands in the relative reactivities of the two hypervalent iron tautomers. Based on these labelling studies, the steric influence exerted by each of the ligands towards the relative reactivity of the oxo ligands of the corresponding pair of Fe(V)(O)(OH) tautomers can be derived. Furthermore, this steric influence can be gauged relative to related complexes/ligands.
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Affiliation(s)
- Mainak Mitra
- Chemical Physics, Department of Chemistry, Lund University, Box 124, SE-221 00, Lund, Sweden.
- Department of Chemistry, Burdwan Raj College, Aftab Avenue, W.B. 713104, India
| | - Alexander Brinkmeier
- Chemical Physics, Department of Chemistry, Lund University, Box 124, SE-221 00, Lund, Sweden.
| | - Yong Li
- Chemical Physics, Department of Chemistry, Lund University, Box 124, SE-221 00, Lund, Sweden.
| | - Margarida Borrell
- QBIS-CAT, Department of Chemistry and Institut de Quimica Computacional i Catàlisi, University of Girona, Campus Montilivi, E-17071 Girona, Spain.
| | - Arnau Call
- QBIS-CAT, Department of Chemistry and Institut de Quimica Computacional i Catàlisi, University of Girona, Campus Montilivi, E-17071 Girona, Spain.
| | - Julio Lloret Fillol
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Avinguda Paisos Catalans 16, 43007, Tarragona, Spain
| | - Michael G Richmond
- Department of Chemistry, University of North Texas, Denton, Texas 76203, USA
| | - Miquel Costas
- QBIS-CAT, Department of Chemistry and Institut de Quimica Computacional i Catàlisi, University of Girona, Campus Montilivi, E-17071 Girona, Spain.
| | - Ebbe Nordlander
- Chemical Physics, Department of Chemistry, Lund University, Box 124, SE-221 00, Lund, Sweden.
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3
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Livesay BN, Shores MP. Influence of Coordinated Triflate Anions on the Solution Magnetic Properties of a Neutral Iron(II) Complex. Inorg Chem 2021; 60:15445-15455. [PMID: 34596394 DOI: 10.1021/acs.inorgchem.1c02112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In an effort to probe the impacts of speciation on spin-state switching, the synthesis and unique solution-phase magnetic properties of [((TIPSC≡C)3tren)Fe(OTf)2] (1) are described. Analysis of the single-crystal X-ray diffraction data shows that the tris(iminoalkyne) ligand coordinates to the iron(II) center through all four nitrogen atoms, while the other two coordination sites are filled by the oxygen atoms from triflate anions. Solid-state variable-temperature (VT) magnetic studies show that 1 remains high-spin (HS) at all temperatures. In the presence of moderately strong coordinating solvents, solvent replaces the two bound triflate counteranions, as observed by 19F NMR spectroscopy and supported by conductivity measurements. VT solution measurements show 1 to be in the HS state when this solvent is oxygen-donating but low-spin (LS) with a nitrogen-donating solvent. In the noncoordinating solvent dichloromethane, both triflates are bound to the iron(II) center at room temperature, but upon cooling, 1 undergoes a coordination change, resulting in the loss of one triflate, as shown by 19F NMR. With the moderately coordinating solvent acetone, triflate dissociation upon cooling results in a spin-switching species with a T1/2 value of 171 K, characterized via 19F NMR, Evans' method, and solution magnetometry measurements. Solution magnetic measurements collected in structurally similar cyclopentanone suggest that the spin-state switching event is exclusive to the acetone environment, suggesting the influence of both the local coordination environment and aggregation. Additionally, a comparison of the solvodoynamic diameters via dynamic light scattering suggests that aggregation of 1 is significantly different in (CH3)2CO and (CD3)2CO, leading to the observation of spin-switching behavior in the former and fully HS behavior in the latter. This study highlights the sensitivity of solution magnetic properties to solvent choice.
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Affiliation(s)
- Brooke N Livesay
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Matthew P Shores
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
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4
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Gunasekera PS, MacMillan SN, Lacy DC. Synthesis and coordination of a tert-butyl functionalized facially coordinating 2-histidine-1-carboxylate model ligand. J COORD CHEM 2021. [DOI: 10.1080/00958972.2021.1878353] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Parami S. Gunasekera
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY, USA
| | | | - David C. Lacy
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY, USA
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5
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Keisers K, Hüppe HM, Iffland-Mühlhaus L, Hoffmann A, Göbel C, Apfel UP, Weber B, Herres-Pawlis S. Interplay of Spin Crossover and Coordination-Induced Spin State Switch for Iron Bis(pyrazolyl)methanes in Solution. Inorg Chem 2020; 59:15343-15354. [PMID: 33002361 DOI: 10.1021/acs.inorgchem.0c02306] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Bis(pyrazolyl)bipyridinylmethane iron(II) complexes show a versatile spin state switching behavior in different solvents. In the solid, the magnetic properties of the compounds have been characterized by X-ray diffraction, Mößbauer spectroscopy, and SQUID magnetometry and point toward a high spin state. For nitrilic solvents, the solvation of the complexes leads to a change of the coordination environment from {N5O} to {N6} and results in a temperature-dependent SCO behavior. Thermodynamic properties of this transformation are obtained via UV/vis spectroscopy, SQUID measurements, and the Evans NMR method. Moreover, a coordination-induced spin state switch (CISSS) to low spin is observed by using methanol as solvent, triggered through a rearrangement of the coordination sphere. The same behavior can be observed by changing the stoichiometry of the ligand-to-metal ratio in MeCN, where the process is reversible. This transformation is monitored via UV/vis spectroscopy, and the resulting new bis-meridional coordination motif, first described for bis(pyrazolyl)methanes, is characterized in the solid state via X-ray diffraction, Mößbauer spectroscopy, and SQUID measurements. The sophisticated correlation of these switchable properties in dependence on different types of solvents reveals that the influence of the solvent on the coordination environment and magnetic properties should not be underestimated. Furthermore, careful investigation is necessary to differentiate between a thermally-induced spin crossover and a coordination-induced spin state switch.
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Affiliation(s)
- Kristina Keisers
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1a, 52074 Aachen, Germany
| | - Henrika M Hüppe
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1a, 52074 Aachen, Germany
| | - Linda Iffland-Mühlhaus
- Inorganic Chemistry I, Ruhr-Universität Bochum, Universitätsstraße 150, 44801 Bochum, Germany
| | - Alexander Hoffmann
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1a, 52074 Aachen, Germany
| | - Christoph Göbel
- Department of Chemistry, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Ulf-Peter Apfel
- Inorganic Chemistry I, Ruhr-Universität Bochum, Universitätsstraße 150, 44801 Bochum, Germany.,Fraunhofer UMSICHT, Osterfelder Straße 3, 46047 Oberhausen, Germany
| | - Birgit Weber
- Department of Chemistry, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Sonja Herres-Pawlis
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1a, 52074 Aachen, Germany
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6
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Taylor MG, Yang T, Lin S, Nandy A, Janet JP, Duan C, Kulik HJ. Seeing Is Believing: Experimental Spin States from Machine Learning Model Structure Predictions. J Phys Chem A 2020; 124:3286-3299. [PMID: 32223165 PMCID: PMC7311053 DOI: 10.1021/acs.jpca.0c01458] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
![]()
Determination of ground-state spins
of open-shell transition-metal
complexes is critical to understanding catalytic and materials properties
but also challenging with approximate electronic structure methods.
As an alternative approach, we demonstrate how structure alone can
be used to guide assignment of ground-state spin from experimentally
determined crystal structures of transition-metal complexes. We first
identify the limits of distance-based heuristics from distributions
of metal–ligand bond lengths of over 2000 unique mononuclear
Fe(II)/Fe(III) transition-metal complexes. To overcome these limits,
we employ artificial neural networks (ANNs) to predict spin-state-dependent
metal–ligand bond lengths and classify experimental ground-state
spins based on agreement of experimental structures with the ANN predictions.
Although the ANN is trained on hybrid density functional theory data,
we exploit the method-insensitivity of geometric properties to enable
assignment of ground states for the majority (ca. 80–90%) of
structures. We demonstrate the utility of the ANN by data-mining the
literature for spin-crossover (SCO) complexes, which have experimentally
observed temperature-dependent geometric structure changes, by correctly
assigning almost all (>95%) spin states in the 46 Fe(II) SCO complex
set. This approach represents a promising complement to more conventional
energy-based spin-state assignment from electronic structure theory
at the low cost of a machine learning model.
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Affiliation(s)
- Michael G Taylor
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Tzuhsiung Yang
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Sean Lin
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Aditya Nandy
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.,Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Jon Paul Janet
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Chenru Duan
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.,Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Heather J Kulik
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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7
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Spin Cross-Over (SCO) Complex Based on Unsymmetrical Functionalized Triazacyclononane Ligand: Structural Characterization and Magnetic Properties. MAGNETOCHEMISTRY 2019. [DOI: 10.3390/magnetochemistry5010019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The unsymmetrical ligand 1-(2-aminophenyl)-4,7-bis(pyridin-2-ylmethyl)-1,4,7-triazacyclononane (L6) has been prepared and characterized by NMR spectroscopy. The L6 ligand is based on the triazamacrocycle (tacn) ring that is functionalized by two flexible 2-pyridylmethyl and one rigid 2-aminophenyl groups. Reaction of this ligand with Fe(ClO4)2·xH2O led to the complex [Fe(L6)](ClO4)2 (1), which was characterized as the first Fe(II) complex based on the unsymmetrical N-functionalized tacn ligand. The crystal structure revealed a discrete monomeric [FeL6]2+ entity in which the unsymmetrical N-functionalized triazacyclononane molecule (L6) acts as hexadentate ligand. As observed in the few parent examples that are based on the symmetrical N-functionalized tacn ligands, the triazacyclononane ring is facially coordinated and the N-donor atoms of the three functional groups (two pyridine and one aniline groups) are disposed in the same side of the tacn ring, leading to a distorted FeN6 environment. The magnetic studies of 1 revealed the presence of an incomplete spin crossover (SCO) transition above 425 K, whose progress would be prevented by a very exothermic thermal decomposition at ca. 472 K, as shown by thermogravimetric and DSC measurements.
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8
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Meng D, Li D, Ollevier T. Recyclable iron(ii) caffeine-derived ionic salt catalyst in the Diels–Alder reaction of cyclopentadiene and α,β-unsaturated N-acyl-oxazolidinones in dimethyl carbonate. RSC Adv 2019; 9:21956-21963. [PMID: 35518890 PMCID: PMC9066430 DOI: 10.1039/c9ra04098f] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 07/03/2019] [Indexed: 11/21/2022] Open
Abstract
Iron(ii) triflate was used in combination with caffeine-derived salts as recyclable catalysts for the Diels–Alder reaction run in dimethyl carbonate (DMC) as a green solvent.
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Affiliation(s)
- Di Meng
- Département de chimie
- Université Laval
- Québec
- Canada G1V 0A6
| | - Dazhi Li
- Département de chimie
- Université Laval
- Québec
- Canada G1V 0A6
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9
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Mitra M, Cusso O, Bhat SS, Sun M, Cianfanelli M, Costas M, Nordlander E. Highly enantioselective epoxidation of olefins by H2O2 catalyzed by a non-heme Fe(ii) catalyst of a chiral tetradentate ligand. Dalton Trans 2019; 48:6123-6131. [DOI: 10.1039/c8dt04449j] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new chiral Fe(ii)-complex mediates the asymmetric epoxidation of prochiral olefins with good enantioselectivity.
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Affiliation(s)
- Mainak Mitra
- Chemical Physics
- Department of Chemistry
- Lund University
- SE-221 00 Lund
- Sweden
| | | | - Satish S. Bhat
- Chemical Physics
- Department of Chemistry
- Lund University
- SE-221 00 Lund
- Sweden
| | - Mingzhe Sun
- Chemical Physics
- Department of Chemistry
- Lund University
- SE-221 00 Lund
- Sweden
| | | | | | - Ebbe Nordlander
- Chemical Physics
- Department of Chemistry
- Lund University
- SE-221 00 Lund
- Sweden
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10
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Banerjee A, Li J, Speelman AL, White CJ, Pawlak PL, Brennessel WW, Lehnert N, Chavez FA. A Structural Model for the Iron-Nitrosyl Adduct of Gentisate Dioxygenase. Eur J Inorg Chem 2018; 2018:4797-4804. [PMID: 32577096 DOI: 10.1002/ejic.201800992] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We present the synthesis, properties, and characterization of [Fe(T1Et4iPrIP)(NO)(H2O)2](OTf)2 (1) (T1Et4iPrIP = Tris(1-ethyl-4-isopropyl-imidazolyl)phosphine) as a model for the nitrosyl adduct of gentisate 1,2-dioxygenase (GDO). The further characterization of [Fe(T1Et4iPrIP)(THF)(NO)(OTf)](OTf) (2) which was previously communicated (Inorg. Chem. 2014, 53, 5414) is also presented. The weighted average Fe-N-O angle of 162° for 1 is very close to linear (≥ 165°) for these types of complexes. The coordinated water ligands participate in hydrogen bonding interactions. The spectral properties (EPR, UV-vis, FTIR) for 1 are compared with 2 and found to be quite comparable. Complex 1 closely follows the relationship between the Fe-N-O angle and NO vibrational frequency which was previously identified for 6-coordinate {FeNO}7 complexes. Liquid FTIR studies on 2 indicate that the ν(NO) vibration position is sensitive to solvent shifting to lower energy (relative to the solid) in donor solvent THF and shifting to higher energy in dichloromethane. The basis for this behavior is discussed. The K eq for NO binding in 2 was calculated in THF and found to be 470 M-1. Density functional theory (DFT) studies on 1 indicate donation of electron density to the iron center from the π* orbitals of formally NO-. Such a donation accounts for the near linearity of the Fe-N-O bond and the large ν(NO) value of 1791 cm-1.
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Affiliation(s)
- Atanu Banerjee
- Department of Chemistry, Oakland University, Rochester, MI 48309-4477, USA
| | - Jia Li
- Department of Chemistry, Oakland University, Rochester, MI 48309-4477, USA
| | - Amy L Speelman
- Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Corey J White
- Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Piotr L Pawlak
- Department of Chemistry, Oakland University, Rochester, MI 48309-4477, USA
| | | | - Nicolai Lehnert
- Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Ferman A Chavez
- Department of Chemistry, Oakland University, Rochester, MI 48309-4477, USA
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11
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Gordon JB, McGale JP, Prendergast JR, Shirani-Sarmazeh Z, Siegler MA, Jameson GNL, Goldberg DP. Structures, Spectroscopic Properties, and Dioxygen Reactivity of 5- and 6-Coordinate Nonheme Iron(II) Complexes: A Combined Enzyme/Model Study of Thiol Dioxygenases. J Am Chem Soc 2018; 140:14807-14822. [PMID: 30346746 PMCID: PMC6596423 DOI: 10.1021/jacs.8b08349] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The synthesis of four new FeII(N4S(thiolate)) complexes as models of the thiol dioxygenases are described. They are composed of derivatives of the neutral, tridentate ligand triazacyclononane (R3TACN; R = Me, iPr) and 2-aminobenzenethiolate (abtx; X = H, CF3), a non-native substrate for thiol dioxygenases. The coordination number of these complexes depends on the identity of the TACN derivative, giving 6-coordinate (6-coord) complexes for FeII(Me3TACN)(abtx)(OTf) (1: X = H; 2: X = CF3) and 5-coordinate (5-coord) complexes for [FeII(iPr3TACN)(abtx)](OTf) (3: X = H; 4: X = CF3). Complexes 1-4 were examined by UV-vis, 1H/19F NMR, and Mössbauer spectroscopies, and density functional theory (DFT) calculations were employed to support the data. Mössbauer spectroscopy reveals that the 6-coord 1-2 and 5-coord 3- 4 exhibit distinct spectra, and these data are compared with that for cysteine-bound CDO, helping to clarify the coordination environment of the cys-bound FeII active site. Reaction of 1 or 2 with O2 at -95 °C leads to S-oxygenation of the abt ligand, and in the case of 2, a rare di(sulfinato)-bridged complex, [Fe2III(μ-O)((2-NH2) p-CF3C6H3SO2)2](OTf)2 ( 5), was obtained. Parallel enzymatic studies on the CDO variant C93G were carried out with the abt substrate and show that reaction with O2 leads to disulfide formation, as opposed to S-oxygenation. The combined model and enzyme studies show that the thiol dioxygenases can operate via a 6-coord FeII center, in contrast to the accepted mechanism for nonheme iron dioxygenases, and that proper substrate chelation to Fe appears to be critical for S-oxygenation.
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Affiliation(s)
- Jesse B Gordon
- Department of Chemistry , The Johns Hopkins University , 3400 North Charles Street , Baltimore , Maryland 21218 , United States
- School of Chemistry , Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne , 30 Flemington Road , Parkville , Victoria 3010 , Australia
| | - Jeremy P McGale
- Department of Chemistry , The Johns Hopkins University , 3400 North Charles Street , Baltimore , Maryland 21218 , United States
- School of Chemistry , Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne , 30 Flemington Road , Parkville , Victoria 3010 , Australia
| | - Joshua R Prendergast
- Department of Chemistry , The Johns Hopkins University , 3400 North Charles Street , Baltimore , Maryland 21218 , United States
- School of Chemistry , Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne , 30 Flemington Road , Parkville , Victoria 3010 , Australia
| | - Zahra Shirani-Sarmazeh
- Department of Chemistry , The Johns Hopkins University , 3400 North Charles Street , Baltimore , Maryland 21218 , United States
- School of Chemistry , Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne , 30 Flemington Road , Parkville , Victoria 3010 , Australia
| | - Maxime A Siegler
- Department of Chemistry , The Johns Hopkins University , 3400 North Charles Street , Baltimore , Maryland 21218 , United States
- School of Chemistry , Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne , 30 Flemington Road , Parkville , Victoria 3010 , Australia
| | - Guy N L Jameson
- Department of Chemistry , The Johns Hopkins University , 3400 North Charles Street , Baltimore , Maryland 21218 , United States
- School of Chemistry , Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne , 30 Flemington Road , Parkville , Victoria 3010 , Australia
| | - David P Goldberg
- Department of Chemistry , The Johns Hopkins University , 3400 North Charles Street , Baltimore , Maryland 21218 , United States
- School of Chemistry , Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne , 30 Flemington Road , Parkville , Victoria 3010 , Australia
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12
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Schober A, Demeshko S, Meyer F. Spin State Variations and Spin-Crossover in Diiron(II) Complexes of Bis(pentadentate) Pyrazolate-Based Ligands. Z Anorg Allg Chem 2018. [DOI: 10.1002/zaac.201800148] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Anne Schober
- Universität Göttingen; Institut für Anorganische Chemie; Tammannstr. 4 37077 Göttingen Germany
| | - Serhiy Demeshko
- Universität Göttingen; Institut für Anorganische Chemie; Tammannstr. 4 37077 Göttingen Germany
| | - Franc Meyer
- Universität Göttingen; Institut für Anorganische Chemie; Tammannstr. 4 37077 Göttingen Germany
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13
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Thompson CV, Davis I, DeGayner JA, Arman HD, Tonzetich ZJ. Iron Pincer Complexes Incorporating Bipyridine: A Strategy for Stabilization of Reactive Species. Organometallics 2017. [DOI: 10.1021/acs.organomet.7b00772] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- C. Vance Thompson
- Department
of Chemistry, University of Texas at San Antonio (UTSA), San Antonio, Texas 78249, United States
| | - Ian Davis
- Department
of Chemistry, University of Texas at San Antonio (UTSA), San Antonio, Texas 78249, United States
| | - Jordan A. DeGayner
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Hadi D. Arman
- Department
of Chemistry, University of Texas at San Antonio (UTSA), San Antonio, Texas 78249, United States
| | - Zachary J. Tonzetich
- Department
of Chemistry, University of Texas at San Antonio (UTSA), San Antonio, Texas 78249, United States
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14
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Li J, Banerjee A, Hasse TA, Loloee R, Biros SM, Staples RJ, Chavez FA. Synthesis and reactivity of a 4His enzyme model complex. RSC Adv 2017; 7:50713-50719. [PMID: 29147561 PMCID: PMC5683714 DOI: 10.1039/c7ra09456f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A new iron(II) complex has been prepared and characterized. [Fe(TrIm)4(OTf)2] (1, TrIm = 1-Tritylimidazole). The solid state structure of 1 has been determined by X-ray crystallography. Compound 1 crystallizes in triclinic space group P1̄, with a = 13.342(7) Å, b = 13.5131(7) Å and c = 13.7025(7) Å. The iron center resides in distorted octahedral geometry coordinated to four equatorial imidazole groups and two axial triflate oxygens groups. The complex is high spin between 20 K and 300 K as indicated by variable field variable temperature magnetic measurements. A fit of the magnetic data yielded g = 2.24 and D = -0.80 cm-1. A large HOMO-LUMO gap energy (3.89 eV) exists for 1 indicating high stability. Addition of H2O2 or t BuOOH to 1 results in formation of an oxygenated intermediate which upon decomposition results in oxidation of the trityl substituent on the imidazole ligand.
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Affiliation(s)
- Jia Li
- Department of Chemistry, Oakland University, Rochester, MI 48309, USA, , Ph: (248) 370-4092
| | - Atanu Banerjee
- Department of Chemistry, Oakland University, Rochester, MI 48309, USA, , Ph: (248) 370-4092
| | - Timothy A Hasse
- Department of Chemistry, Oakland University, Rochester, MI 48309, USA, , Ph: (248) 370-4092
| | - Reza Loloee
- Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, USA
| | - Shannon M Biros
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Richard J Staples
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Ferman A Chavez
- Department of Chemistry, Oakland University, Rochester, MI 48309, USA, , Ph: (248) 370-4092
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15
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Li J, Molenda MA, Biros SM, Staples RJ, Chavez FA. Assembly of a mononuclear ferrous site using a bulky aldehyde-imidazole ligand. Inorganica Chim Acta 2017; 464:152-156. [PMID: 29238096 PMCID: PMC5724793 DOI: 10.1016/j.ica.2017.05.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A new iron(II) complex has been prepared and characterized. [Fe(TrImA)2(OTf)2] (1, TrImA = 1-Tritylimidazole-4-carboxaldehyde). The solid state structure of 1 has been determined by X-ray crystallography. Compound 1 crystallizes in monoclinic space group P21/c, with a = 10.8323(18) Å, b = 8.1606(13) Å and c = 24.818(4) Å. The iron center is coordinated to two imidazole groups, two pendant aldehyde-derived carbonyl oxygens and two triflate oxygens. The complex is high spin between 300 and 20 K as indicated by variable field variable temperature magnetic measurements. A fit of the magnetic data yielded g = 2.17 and D = 4.05 cm-1. A large HOMO-LUMO gap energy (4.49 eV) exists for 1 indicating high stability.
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Affiliation(s)
- Jia Li
- Department of Chemistry, Oakland University, Rochester, MI 48309, USA
| | - Monika A Molenda
- Department of Chemistry, Oakland University, Rochester, MI 48309, USA
| | - Shannon M Biros
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Richard J Staples
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Ferman A Chavez
- Department of Chemistry, Oakland University, Rochester, MI 48309, USA
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16
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Groizard T, Papior N, Le Guennic B, Robert V, Kepenekian M. Enhanced Cooperativity in Supported Spin-Crossover Metal-Organic Frameworks. J Phys Chem Lett 2017; 8:3415-3420. [PMID: 28669188 DOI: 10.1021/acs.jpclett.7b01248] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The impact of surface deposition on cooperativity is explored in Au(111)-supported self-assembled metal-organic frameworks (MOFs) based on Fe(II) ions. Using a thermodynamic model, we first demonstrate that dimensionality reduction combined with deposition on a metal surface is likely to deeply enhance the spin-crossover cooperativity, going from γ3D = 16 K for the bulk material to γ2Dsupp = 386 K for its 2D supported derivative. On the basis of density functional theory, we then elucidate the electronic structure of a promising Fe-based MOF. A chemical strategy is proposed to turn a weakly interacting magnetic system into a strongly cooperative spin-crossover monolayer with γMOFAu(111) = 83 K. These results open a promising route to the fabrication of cooperative materials based on SCO Fe(II) platforms.
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Affiliation(s)
- Thomas Groizard
- Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes 1, CNRS, UMR 6226 , 35042 Rennes, France
| | - Nick Papior
- ICN2 - Institut Catala de Nanociencia i Nanotecnologia, Campus UAB , 08193 Bellaterra (Barcelona), Spain
| | - Boris Le Guennic
- Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes 1, CNRS, UMR 6226 , 35042 Rennes, France
| | - Vincent Robert
- Laboratoire de Chimie Quantique, Université de Strasbourg, CNRS, UMR 7177 , 67081 Strasbourg, France
| | - Mikaël Kepenekian
- Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes 1, CNRS, UMR 6226 , 35042 Rennes, France
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17
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Déniel K, Cosquer N, Conan F, Triki S, Gómez-García CJ. Coordination polymers based on bridging cyanocarbanions and bis-tridentate p-phenylenediamine ligands. Polyhedron 2017. [DOI: 10.1016/j.poly.2016.09.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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18
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Chorazy S, Stanek JJ, Kobylarczyk J, Ohkoshi SI, Sieklucka B, Podgajny R. Modulation of the FeII spin crossover effect in the pentadecanuclear {Fe9[M(CN)8]6} (M = Re, W) clusters by facial coordination of tridentate polyamine ligands. Dalton Trans 2017; 46:8027-8036. [DOI: 10.1039/c7dt01416c] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
N,N,N-tridentate ligands coordinated to {Fe9[M(CN)8]6} (M = Re, W) induce the spin crossover on the external Fe sites of the cluster.
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Affiliation(s)
- Szymon Chorazy
- Faculty of Chemistry
- Jagiellonian University
- 30-060 Krakow
- Poland
- Department of Chemistry
| | - Jan J. Stanek
- Marian Smoluchowski Institute of Physics
- Jagiellonian University
- 30-348 Krakow
- Poland
| | | | - Shin-ichi Ohkoshi
- Department of Chemistry
- School of Science
- The University of Tokyo
- Tokyo 113-0033
- Japan
| | | | - Robert Podgajny
- Faculty of Chemistry
- Jagiellonian University
- 30-060 Krakow
- Poland
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19
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Khusniyarov MM. How to Switch Spin-Crossover Metal Complexes at Constant Room Temperature. Chemistry 2016; 22:15178-15191. [DOI: 10.1002/chem.201601140] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Indexed: 12/27/2022]
Affiliation(s)
- Marat M. Khusniyarov
- Department of Chemistry and Pharmacy; Friedrich-Alexander University Erlangen-Nürnberg (FAU); Egerlandstr. 1 91058 Erlangen Germany
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20
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Conde A, Sabenya G, Rodríguez M, Postils V, Luis JM, Díaz-Requejo MM, Costas M, Pérez PJ. Iron and Manganese Catalysts for the Selective Functionalization of Arene C(sp2
)−H Bonds by Carbene Insertion. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201601750] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Ana Conde
- Laboratorio de Catálisis Homogénea; Unidad Asociada al CSIC; CIQSO-Centro de Investigación en Química Sostenible; Departamento de Química; Universidad de Huelva; Campus de El Carmen s/n 21007 Huelva Spain
| | - Gerard Sabenya
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química; Universitat de Girona; Campus Montilivi 17071 Girona Spain
| | - Mònica Rodríguez
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química; Universitat de Girona; Campus Montilivi 17071 Girona Spain
| | - Verònica Postils
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química; Universitat de Girona; Campus Montilivi 17071 Girona Spain
| | - Josep M. Luis
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química; Universitat de Girona; Campus Montilivi 17071 Girona Spain
| | - M. Mar Díaz-Requejo
- Laboratorio de Catálisis Homogénea; Unidad Asociada al CSIC; CIQSO-Centro de Investigación en Química Sostenible; Departamento de Química; Universidad de Huelva; Campus de El Carmen s/n 21007 Huelva Spain
| | - Miquel Costas
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química; Universitat de Girona; Campus Montilivi 17071 Girona Spain
| | - Pedro J. Pérez
- Laboratorio de Catálisis Homogénea; Unidad Asociada al CSIC; CIQSO-Centro de Investigación en Química Sostenible; Departamento de Química; Universidad de Huelva; Campus de El Carmen s/n 21007 Huelva Spain
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21
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Conde A, Sabenya G, Rodríguez M, Postils V, Luis JM, Díaz-Requejo MM, Costas M, Pérez PJ. Iron and Manganese Catalysts for the Selective Functionalization of Arene C(sp2
)−H Bonds by Carbene Insertion. Angew Chem Int Ed Engl 2016; 55:6530-4. [DOI: 10.1002/anie.201601750] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Ana Conde
- Laboratorio de Catálisis Homogénea; Unidad Asociada al CSIC; CIQSO-Centro de Investigación en Química Sostenible; Departamento de Química; Universidad de Huelva; Campus de El Carmen s/n 21007 Huelva Spain
| | - Gerard Sabenya
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química; Universitat de Girona; Campus Montilivi 17071 Girona Spain
| | - Mònica Rodríguez
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química; Universitat de Girona; Campus Montilivi 17071 Girona Spain
| | - Verònica Postils
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química; Universitat de Girona; Campus Montilivi 17071 Girona Spain
| | - Josep M. Luis
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química; Universitat de Girona; Campus Montilivi 17071 Girona Spain
| | - M. Mar Díaz-Requejo
- Laboratorio de Catálisis Homogénea; Unidad Asociada al CSIC; CIQSO-Centro de Investigación en Química Sostenible; Departamento de Química; Universidad de Huelva; Campus de El Carmen s/n 21007 Huelva Spain
| | - Miquel Costas
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química; Universitat de Girona; Campus Montilivi 17071 Girona Spain
| | - Pedro J. Pérez
- Laboratorio de Catálisis Homogénea; Unidad Asociada al CSIC; CIQSO-Centro de Investigación en Química Sostenible; Departamento de Química; Universidad de Huelva; Campus de El Carmen s/n 21007 Huelva Spain
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22
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Hogue RW, Feltham HLC, Miller RG, Brooker S. Spin Crossover in Dinuclear N4S2 Iron(II) Thioether–Triazole Complexes: Access to [HS-HS], [HS-LS], and [LS-LS] States. Inorg Chem 2016; 55:4152-65. [DOI: 10.1021/acs.inorgchem.5b02851] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ross W. Hogue
- Department of Chemistry and MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Otago,
PO Box 56, Dunedin 9054, New Zealand
| | - Humphrey L. C. Feltham
- Department of Chemistry and MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Otago,
PO Box 56, Dunedin 9054, New Zealand
| | - Reece G. Miller
- Department of Chemistry and MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Otago,
PO Box 56, Dunedin 9054, New Zealand
| | - Sally Brooker
- Department of Chemistry and MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Otago,
PO Box 56, Dunedin 9054, New Zealand
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23
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Olivo G, Nardi M, Vìdal D, Barbieri A, Lapi A, Gómez L, Lanzalunga O, Costas M, Di Stefano S. C-H Bond Oxidation Catalyzed by an Imine-Based Iron Complex: A Mechanistic Insight. Inorg Chem 2015; 54:10141-52. [PMID: 26457760 DOI: 10.1021/acs.inorgchem.5b01500] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A family of imine-based nonheme iron(II) complexes (LX)2Fe(OTf)2 has been prepared, characterized, and employed as C-H oxidation catalysts. Ligands LX (X = 1, 2, 3, and 4) stand for tridentate imine ligands resulting from spontaneous condensation of 2-pycolyl-amine and 4-substituted-2-picolyl aldehydes. Fast and quantitative formation of the complex occurs just upon mixing aldehyde, amine, and Fe(OTf)2 in a 2:2:1 ratio in acetonitrile solution. The solid-state structures of (L1)2Fe(OTf)(ClO4) and (L3)2Fe(OTf)2 are reported, showing a low-spin octahedral iron center, with the ligands arranged in a meridional fashion. (1)H NMR analyses indicate that the solid-state structure and spin state is retained in solution. These analyses also show the presence of an amine-imine tautomeric equilibrium. (LX)2Fe(OTf)2 efficiently catalyze the oxidation of alkyl C-H bonds employing H2O2 as a terminal oxidant. Manipulation of the electronic properties of the imine ligand has only a minor impact on efficiency and selectivity of the oxidative process. A mechanistic study is presented, providing evidence that C-H oxidations are metal-based. Reactions occur with stereoretention at the hydroxylated carbon and selectively at tertiary over secondary C-H bonds. Isotopic labeling analyses show that H2O2 is the dominant origin of the oxygen atoms inserted in the oxygenated product. Experimental evidence is provided that reactions involve initial oxidation of the complexes to the ferric state, and it is proposed that a ligand arm dissociates to enable hydrogen peroxide binding and activation. Selectivity patterns and isotopic labeling studies strongly suggest that activation of hydrogen peroxide occurs by heterolytic O-O cleavage, without the assistance of a cis-binding water or alkyl carboxylic acid. The sum of these observations provides sound evidence that controlled activation of H2O2 at (LX)2Fe(OTf)2 differs from that occurring in biomimetic iron catalysts described to date.
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Affiliation(s)
- Giorgio Olivo
- Dipartimento di Chimica, Università degli Studi di Roma "La Sapienza" and Istituto CNR di Metodologie Chimiche (IMC-CNR), Sezione Meccanismi di Reazione, c/o Dipartimento di Chimica, Università degli Studi di Roma "La Sapienza", P.le A. Moro 5, I-00185 Rome, Italy.,Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona , Campus de Montilivi, 17071 Girona, Spain
| | - Martina Nardi
- Dipartimento di Chimica, Università degli Studi di Roma "La Sapienza" and Istituto CNR di Metodologie Chimiche (IMC-CNR), Sezione Meccanismi di Reazione, c/o Dipartimento di Chimica, Università degli Studi di Roma "La Sapienza", P.le A. Moro 5, I-00185 Rome, Italy
| | - Diego Vìdal
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona , Campus de Montilivi, 17071 Girona, Spain
| | - Alessia Barbieri
- Dipartimento di Chimica, Università degli Studi di Roma "La Sapienza" and Istituto CNR di Metodologie Chimiche (IMC-CNR), Sezione Meccanismi di Reazione, c/o Dipartimento di Chimica, Università degli Studi di Roma "La Sapienza", P.le A. Moro 5, I-00185 Rome, Italy
| | - Andrea Lapi
- Dipartimento di Chimica, Università degli Studi di Roma "La Sapienza" and Istituto CNR di Metodologie Chimiche (IMC-CNR), Sezione Meccanismi di Reazione, c/o Dipartimento di Chimica, Università degli Studi di Roma "La Sapienza", P.le A. Moro 5, I-00185 Rome, Italy.,Consortium of Chemical Catalysis and Reactivity, CIRCC Interuniversity , Via Celso Ulpiani 27, 70126 Bari, Italy
| | - Laura Gómez
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona , Campus de Montilivi, 17071 Girona, Spain.,Serveis Tècnics de Recerca (STR), Universitat de Girona , Parc Cientı́fic i Tecnològic, E-17003 Girona, Spain
| | - Osvaldo Lanzalunga
- Dipartimento di Chimica, Università degli Studi di Roma "La Sapienza" and Istituto CNR di Metodologie Chimiche (IMC-CNR), Sezione Meccanismi di Reazione, c/o Dipartimento di Chimica, Università degli Studi di Roma "La Sapienza", P.le A. Moro 5, I-00185 Rome, Italy.,Consortium of Chemical Catalysis and Reactivity, CIRCC Interuniversity , Via Celso Ulpiani 27, 70126 Bari, Italy
| | - Miquel Costas
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona , Campus de Montilivi, 17071 Girona, Spain
| | - Stefano Di Stefano
- Dipartimento di Chimica, Università degli Studi di Roma "La Sapienza" and Istituto CNR di Metodologie Chimiche (IMC-CNR), Sezione Meccanismi di Reazione, c/o Dipartimento di Chimica, Università degli Studi di Roma "La Sapienza", P.le A. Moro 5, I-00185 Rome, Italy.,Consortium of Chemical Catalysis and Reactivity, CIRCC Interuniversity , Via Celso Ulpiani 27, 70126 Bari, Italy
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24
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England J, Prakash J, Cranswick MA, Mandal D, Guo Y, Münck E, Shaik S, Que L. Oxoiron(IV) Complex of the Ethylene-Bridged Dialkylcyclam Ligand Me2EBC. Inorg Chem 2015; 54:7828-39. [PMID: 26244657 DOI: 10.1021/acs.inorgchem.5b00861] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We report herein the first example of an oxoiron(IV) complex of an ethylene-bridged dialkylcyclam ligand, [Fe(IV)(O)(Me2EBC)(NCMe)](2+) (2; Me2EBC = 4,11-dimethyl-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane). Complex 2 has been characterized by UV-vis, (1)H NMR, resonance Raman, Mössbauer, and X-ray absorption spectroscopy as well as electrospray ionization mass spectrometry, and its properties have been compared with those of the closely related [Fe(IV)(O)(TMC)(NCMe)](2+) (3; TMC = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane), the intensively studied prototypical oxoiron(IV) complex of the macrocyclic tetramethylcyclam ligand. Me2EBC has an N4 donor set nearly identical with that of TMC but possesses an ethylene bridge in place of the 1- and 8-methyl groups of TMC. As a consequence, Me2EBC is forced to deviate from the trans-I configuration typically found for Fe(IV)(O)(TMC) complexes and instead adopts a folded cis-V stereochemistry that requires the MeCN ligand to coordinate cis to the Fe(IV)═O unit in 2 rather than in the trans arrangement found in 3. However, switching from the trans geometry of 3 to the cis geometry of 2 did not significantly affect their ground-state electronic structures, although a decrease in ν(Fe═O) was observed for 2. Remarkably, despite having comparable Fe(IV/III) reduction potentials, 2 was found to be significantly more reactive than 3 in both oxygen-atom-transfer (OAT) and hydrogen-atom-transfer (HAT) reactions. A careful analysis of density functional theory calculations on the HAT reactivity of 2 and 3 revealed the root cause to be the higher oxyl character of 2, leading to a stronger O---H bond specifically in the quintet transition state.
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Affiliation(s)
- Jason England
- †Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Jai Prakash
- †Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Matthew A Cranswick
- †Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Debasish Mandal
- §Institute of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel
| | - Yisong Guo
- ‡Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Eckard Münck
- ‡Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Sason Shaik
- §Institute of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel
| | - Lawrence Que
- †Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, United States
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25
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Samanta S, Demesko S, Dechert S, Meyer F. A two-in-one pincer ligand and its diiron(II) complex showing spin state switching in solution through reversible ligand exchange. Angew Chem Int Ed Engl 2015; 54:583-7. [PMID: 25412962 DOI: 10.1002/anie.201408966] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Indexed: 11/09/2022]
Abstract
A novel pyrazolate-bridged ligand providing two {PNN} pincer-type compartments has been synthesized. Its diiron(II) complex LFe2(OTf)3(CH3CN) (1; Tf = triflate) features, in solid state, two bridging triflate ligands, with a terminal triflate and a MeCN ligand completing the octahedral coordination spheres of the two high-spin metal ions. In MeCN solution, 1 is shown to undergo a sequential, reversible, and complete spin transition to the low-spin state upon cooling. Detailed UV/Vis and (19)F NMR spectroscopic studies as well as magnetic measurements have unraveled that spin state switching correlates with a rapid multistep triflate/MeCN ligand exchange equilibrium. The spin transition temperature can be continuously tuned by varying the triflate concentration in solution.
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Affiliation(s)
- Subhas Samanta
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstrasse 4, 37077 Göttingen (Germany) http://www.meyer.chemie.uni-goettingen.de
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26
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Samanta S, Demesko S, Dechert S, Meyer F. A Two-in-one Pincer Ligand and its Diiron(II) Complex Showing Spin State Switching in Solution through Reversible Ligand Exchange. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201408966] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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27
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Falkenhagen JP, Braun B, Bill E, Sattler D, Limberg C. A cubic Fe4Mo4 oxo framework and its reversible four-electron redox chemistry. Inorg Chem 2014; 53:7294-308. [PMID: 24981960 DOI: 10.1021/ic500584a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The potential of iron molybdates as catalysts in the Formox process stimulates research on aggregated but molecular iron-molybdenum oxo compounds. In this context, [(Me3TACN)Fe](OTf)2 was reacted with (nBu4N)2[MoO4], which led to an oxo cluster, [[(Me3TACN)Fe][μ-(MoO4-κ(3)O,O',O″)]]4 (1, Fe4Mo4) with a distorted cubic structure, where the corners are occupied by (Me3TACN)Fe(2+) and [Mo═O](4+) units in an alternating fashion, being bridged by oxido ligands. The cyclic voltammogram revealed four reversible oxidation waves that are assigned to four consecutive Fe(II) → Fe(III) transfers and motivated attempts to isolate compounds containing the respective cations. Indeed, a salt with a Fe(II)2Fe(III)2Mo(VI)4 constellation, [Fe4Mo4](TCNQ)2 (2), could be isolated after treatment with TCNQ. The Fe(II)Fe(III)3Mo(VI)4 stage could be reached via oxidation with DDQ or 3 equiv of thianthrenium hexafluorophosphate (ThPF6), giving [Fe4Mo4](DDQ)3 (4) or [Fe4Mo4](PF6)3 (5), respectively. The fully oxidized Fe(III)4Mo(VI)4 state was generated through oxidation with 4 equiv of ThPF6, leading to [Fe4Mo4](PF6)4, which showed a unique behavior: upon storage, one of the [Mo═O](4+) corners inverts, so that the terminal oxido ligand is located in the interior of the cage, leading to the formation of [[(Me3TACN)Fe]4[μ-([MoO4]3[MoO4(MeCN-κN)])-κ(3)O,O',O″)](PF6)4 (7). In this form, the compound could no longer be employed to enter the cyclic voltammogram recorded for 1, 3, and 5 from the oxidized side; no discrete redox events were observed. Compounds 1-3 and 7 were characterized structurally and 1, 3, and 7 additionally by SQUID measurements and Mössbauer spectroscopy. The data reveal a high degree of charge delocalization. (16)O/(18)O exchange experiments with labeled water performed with 1 revealed an interesting parallel with the Formox catalyst: water-(18)O exchanges its label with all of the oxido ligands (bridging and terminal). This property relates to the ion mobility being held responsible for the activity of iron molybdate catalysts compared to neat MoO3 or Fe2O3.
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Affiliation(s)
- Jan P Falkenhagen
- Institut für Chemie, Humboldt-Universität zu Berlin , Brook-Taylor-Straße 2, 12489 Berlin, Germany
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Oishi M, Endo T, Oshima M, Suzuki H. Aluminum-stabilized low-spin iron(II) hydrido complexes of 1,4,7-trimethyl-1,4,7-triazacyclononane. Inorg Chem 2014; 53:5100-8. [PMID: 24801527 DOI: 10.1021/ic500195q] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We investigated herein the reactions of (Me3tacn)FeCln (1a: n = 3, 1b: n = 2) with common aluminum hydride reagents and a bulky dihydridoaluminate {Li(ether)2}{Al(OC6H3-2,6-(t)Bu2)}(μ-H)2, which yielded the diamagnetic hydrido complexes 2-4 containing Fe(II) and Al(III). In particular, the use of divalent 1b afforded excellent isolated yields. The structures of 2-4 were determined using spectroscopic and crystallographic analyses. The crystal structures showed distorted octahedral Fe centers and fairly short Fe-Al distances [2.19-2.24 Å]. The structures of cation moiety 2 and neutral complex 4 were further probed using DFT calculations, which indicated a stable low-spin Fe(II) state and strongly electron-donating nature of the (Me3tacn)FeH3 fragment toward the Al(III) center.
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Affiliation(s)
- Masataka Oishi
- Graduate School of Science and Engineering, Tokyo Institute of Technology , 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552, Japan
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Nitschke C, Köckerling M, Bernhardt E, Küppers T, Willner H. Structural diversity and spectral and thermal properties of the first alkaline earth metal tetracyanidoborates: [Mg(H2O)6][B(CN)4]2, [Mg(H2O)2][B(CN)4]2, [Mg(DMF)6][B(CN)4]2, [Ca(H2O)3][B(CN)4]2, and [Ca(H2O)2(CH3CN)][B(CN)4]2. Dalton Trans 2014; 43:7128-38. [DOI: 10.1039/c3dt51945g] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The syntheses, structures, and spectral and thermal properties of the first tetracyanidoborate salts coordinating weakly to solvated alkaline earth cations are discussed.
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Affiliation(s)
- Christian Nitschke
- Institut für Chemie
- Anorganische Chemie/Festkörperchemie
- Universität Rostock
- D-18059 Rostock, Germany
| | - Martin Köckerling
- Institut für Chemie
- Anorganische Chemie/Festkörperchemie
- Universität Rostock
- D-18059 Rostock, Germany
| | - Eduard Bernhardt
- FB C – Anorganische Chemie
- Bergische Universität Wuppertal
- D-42119 Wuppertal, Germany
| | - Torsten Küppers
- FB C – Anorganische Chemie
- Bergische Universität Wuppertal
- D-42119 Wuppertal, Germany
| | - Helge Willner
- FB C – Anorganische Chemie
- Bergische Universität Wuppertal
- D-42119 Wuppertal, Germany
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Mitra M, Lloret-Fillol J, Haukka M, Costas M, Nordlander E. Evidence that steric factors modulate reactivity of tautomeric iron–oxo species in stereospecific alkane C–H hydroxylation. Chem Commun (Camb) 2014; 50:1408-10. [DOI: 10.1039/c3cc47830k] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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31
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Hasserodt J, Kolanowski JL, Touti F. Magnetogenese in Wasser, ausgelöst durch einen chemischen Analyten. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201305662] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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32
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Hasserodt J, Kolanowski JL, Touti F. Magnetogenesis in Water Induced by a Chemical Analyte. Angew Chem Int Ed Engl 2013; 53:60-73. [DOI: 10.1002/anie.201305662] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Indexed: 11/12/2022]
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Cussó O, Garcia-Bosch I, Ribas X, Lloret-Fillol J, Costas M. Asymmetric epoxidation with H2O2 by manipulating the electronic properties of non-heme iron catalysts. J Am Chem Soc 2013; 135:14871-8. [PMID: 24060452 DOI: 10.1021/ja4078446] [Citation(s) in RCA: 186] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A non-heme iron complex that catalyzes highly enantioselective epoxidation of olefins with H2O2 is described. Improvement of enantiomeric excesses is attained by the use of catalytic amounts of carboxylic acid additives. Electronic effects imposed by the ligand on the iron center are shown to synergistically cooperate with catalytic amounts of carboxylic acids in promoting efficient O-O cleavage and creating highly chemo- and enantioselective epoxidizing species which provide a broad range of epoxides in synthetically valuable yields and short reaction times.
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Affiliation(s)
- Olaf Cussó
- QBIS ResearchGroup, Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona , Campus Montilivi, Girona E-17071, Catalonia, Spain
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Prat I, Company A, Corona T, Parella T, Ribas X, Costas M. Assessing the Impact of Electronic and Steric Tuning of the Ligand in the Spin State and Catalytic Oxidation Ability of the FeII(Pytacn) Family of Complexes. Inorg Chem 2013; 52:9229-44. [DOI: 10.1021/ic4004033] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Irene Prat
- Grup de Química Bioinorgànica
i Supramolecular (QBIS), Institut de Química Computacional
i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, E17071 Girona,
Catalonia, Spain
| | - Anna Company
- Grup de Química Bioinorgànica
i Supramolecular (QBIS), Institut de Química Computacional
i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, E17071 Girona,
Catalonia, Spain
| | - Teresa Corona
- Grup de Química Bioinorgànica
i Supramolecular (QBIS), Institut de Química Computacional
i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, E17071 Girona,
Catalonia, Spain
| | - Teodor Parella
- Servei
de Ressonància
Magnètica Nuclear, Universitat Autònoma de Barcelona, Bellaterra, E08193 Barcelona, Catalonia,
Spain
| | - Xavi Ribas
- Grup de Química Bioinorgànica
i Supramolecular (QBIS), Institut de Química Computacional
i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, E17071 Girona,
Catalonia, Spain
| | - Miquel Costas
- Grup de Química Bioinorgànica
i Supramolecular (QBIS), Institut de Química Computacional
i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, E17071 Girona,
Catalonia, Spain
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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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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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37
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Tsitovich PB, Morrow JR. Macrocyclic ligands for Fe(II) paraCEST and chemical shift MRI contrast agents. Inorganica Chim Acta 2012. [DOI: 10.1016/j.ica.2012.06.010] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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38
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Podgajny R, Chorazy S, Nitek W, Rams M, Majcher AM, Marszałek B, Żukrowski J, Kapusta C, Sieklucka B. Co-NC-W and Fe-NC-W Electron-Transfer Channels for Thermal Bistability in Trimetallic {Fe6Co3[W(CN)8]6} Cyanido-Bridged Cluster. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/anie.201208023] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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39
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Podgajny R, Chorazy S, Nitek W, Rams M, Majcher AM, Marszałek B, Żukrowski J, Kapusta C, Sieklucka B. Co-NC-W and Fe-NC-W Electron-Transfer Channels for Thermal Bistability in Trimetallic {Fe6Co3[W(CN)8]6} Cyanido-Bridged Cluster. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201208023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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40
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Synthesis and structure of binuclear iron(ii) complex with the cage-like ligand as a model of methane monooxygenase. Russ Chem Bull 2012. [DOI: 10.1007/s11172-011-0319-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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41
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Ward AL, Elbaz L, Kerr JB, Arnold J. Nonprecious metal catalysts for fuel cell applications: electrochemical dioxygen activation by a series of first row transition metal tris(2-pyridylmethyl)amine complexes. Inorg Chem 2012; 51:4694-706. [PMID: 22458367 DOI: 10.1021/ic2026957] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A series of divalent first row triflate complexes supported by the ligand tris(2-pyridylmethyl)amine (TPA) have been investigated as oxygen reduction catalysts for fuel cell applications. [(TPA)M(2+)](n+) (M = Mn, Fe, Co, Ni, and Cu) derivatives were synthesized and characterized by X-ray crystallography, cyclic voltammetry, NMR spectroscopy, magnetic susceptibility, IR spectroscopy, and conductance measurements. The stoichiometric and electrochemical O(2) reactivities of the series were examined. Rotating-ring disk electrode (RRDE) voltammetry was used to examine the catalytic activity of the complexes on a carbon support in acidic media, emulating fuel cell performance. The iron complex displayed a selectivity of 89% for four-electron conversion and demonstrated the fastest reaction kinetics, as determined by a kinetic current of 7.6 mA. Additionally, the Mn, Co, and Cu complexes all showed selective four-electron oxygen reduction (<28% H(2)O(2)) at onset potentials (~0.44 V vs RHE) comparable to state of the art molecular catalysts, while being straightforward to access synthetically and derived from nonprecious metals.
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Affiliation(s)
- Ashleigh L Ward
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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42
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Dorazio SJ, Morrow JR. The Development of Iron(II) Complexes as ParaCEST MRI Contrast Agents. Eur J Inorg Chem 2012. [DOI: 10.1002/ejic.201101169] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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43
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Synthesis of two-coordinate iron aryloxides and their reactions with organic azide: Intramolecular C–H bond amination. J Organomet Chem 2011. [DOI: 10.1016/j.jorganchem.2011.06.049] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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44
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Furukawa S, Hitomi Y, Shishido T, Tanaka T. Efficient aerobic oxidation of hydrocarbons promoted by high-spin nonheme Fe(II) complexes without any reductant. Inorganica Chim Acta 2011. [DOI: 10.1016/j.ica.2011.08.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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45
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Nitschke C, Köckerling M. Iron Salts with the Tetracyanidoborate Anion: [FeIII(H2O)6][B(CN)4]3, Coordination Polymer [FeII(H2O)2{κ2N[B(CN)4]}2], and [FeII(DMF)6][B(CN)4]2. Inorg Chem 2011; 50:4313-21. [DOI: 10.1021/ic102278z] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Christian Nitschke
- Institute of Chemistry, Inorganic-Solid State Chemistry Group, University of Rostock, Albert-Einstein-Strasse 3a, D-18059 Rostock, Germany
| | - Martin Köckerling
- Institute of Chemistry, Inorganic-Solid State Chemistry Group, University of Rostock, Albert-Einstein-Strasse 3a, D-18059 Rostock, Germany
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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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47
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Atmani C, El Hajj F, Benmansour S, Marchivie M, Triki S, Conan F, Patinec V, Handel H, Dupouy G, Gómez-García CJ. Guidelines to design new spin crossover materials. Coord Chem Rev 2010. [DOI: 10.1016/j.ccr.2009.11.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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48
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Filimon SA, Hrib C, Randoll S, Neda I, Jones P, Tamm M. Quinine-Derived Imidazolidin-2-imine Ligands: Synthesis, Coordination Chemistry, and Application in Catalytic Transfer Hydrogenation. Z Anorg Allg Chem 2010. [DOI: 10.1002/zaac.200900485] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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49
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El Hajj F, Sebki G, Patinec V, Marchivie M, Triki S, Handel H, Yefsah S, Tripier R, Gómez-García CJ, Coronado E. Macrocycle-based spin-crossover materials. Inorg Chem 2010; 48:10416-23. [PMID: 19780566 DOI: 10.1021/ic9012476] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
New iron(II) complexes of formula [Fe(L1)](BF(4))(2) (1) and [Fe(L2)](BF(4))(2) x H(2)O (2) (L1 = 1,7-bis(2'-pyridylmethyl)-1,4,7,10-tetraazacyclododecane; L2 = 1,8-bis(2'-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane) have been synthesized and characterized by infrared spectroscopy, variable-temperature single-crystal X-ray diffraction, and variable-temperature magnetic susceptibility measurements. The crystal structure determinations of 1 and 2 reveal in both cases discrete iron(II) monomeric structures in which the two functionalized tetraazamacrocycles (L1 and L2) act as hexadentate ligands; the iron(II) ions are coordinated with six nitrogen atoms: four from the macrocycle and two from two pyridine groups occupying two cis positions around the metal ion. In 1, the N-Fe-N bond angles indicate that the Fe(II) ion adopts an unusual distorted trigonal prismatic geometry. In agreement with the observed paramagnetic behavior, the average of the six Fe-N distances at 293 K (2.218(6) A) and at 90 K (2.209(2) A) correspond well with distances observed for high-spin (HS) Fe(II) complexes with a coordination index of 6. For 2, the Fe(II) ion adopts a distorted octahedral geometry for which the six Fe-N distances (average 2.197(4) A) at room temperature are in the range expected for HS Fe(II) complexes. The crystal structure solved at 90 K showed a strong modification of the iron coordination sphere, suggesting the presence of a spin-crossover transition from HS to low spin (LS). Surprisingly, the averaged Fe-N value (2.077(4) A) at this temperature is not in agreement with the magnetic measurements since the chi(m)T product versus T showed a full LS state at 90 K. This may be explained by the presence of important distortions arising from the macrocycle constraints. To understand how the crystal and the lattice parameters were affected by the magnetic transition, the temperature dependence of the lattice parameters of 2 was determined in the range 293-90 K: the a and b parameters show essentially linear and gradual decreases, while the c and beta parameters show dramatic decreases nearly similar to that observed in the magnetic behavior.
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Affiliation(s)
- Fatima El Hajj
- UMR CNRS 6521, Chimie, Electrochimie Moleculaires, Chimie Analytique, Université de Bretagne Occidentale, BP 809, 29285 Brest Cedex, France
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