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Gigli L, Silva JM, Cerofolini L, Macedo AL, Geraldes CFGC, Suturina EA, Calderone V, Fragai M, Parigi G, Ravera E, Luchinat C. Machine Learning-Enhanced Quantum Chemistry-Assisted Refinement of the Active Site Structure of Metalloproteins. Inorg Chem 2024; 63:10713-10725. [PMID: 38805564 DOI: 10.1021/acs.inorgchem.4c01274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
Understanding the fine structural details of inhibitor binding at the active site of metalloenzymes can have a profound impact on the rational drug design targeted to this broad class of biomolecules. Structural techniques such as NMR, cryo-EM, and X-ray crystallography can provide bond lengths and angles, but the uncertainties in these measurements can be as large as the range of values that have been observed for these quantities in all the published structures. This uncertainty is far too large to allow for reliable calculations at the quantum chemical (QC) levels for developing precise structure-activity relationships or for improving the energetic considerations in protein-inhibitor studies. Therefore, the need arises to rely upon computational methods to refine the active site structures well beyond the resolution obtained with routine application of structural methods. In a recent paper, we have shown that it is possible to refine the active site of cobalt(II)-substituted MMP12, a metalloprotein that is a relevant drug target, by matching to the experimental pseudocontact shifts (PCS) those calculated using multireference ab initio QC methods. The computational cost of this methodology becomes a significant bottleneck when the starting structure is not sufficiently close to the final one, which is often the case with biomolecular structures. To tackle this problem, we have developed an approach based on a neural network (NN) and a support vector regression (SVR) and applied it to the refinement of the active site structure of oxalate-inhibited human carbonic anhydrase 2 (hCAII), another prototypical metalloprotein target. The refined structure gives a remarkably good agreement between the QC-calculated and the experimental PCS. This study not only contributes to the knowledge of CAII but also demonstrates the utility of combining machine learning (ML) algorithms with QC calculations, offering a promising avenue for investigating other drug targets and complex biological systems in general.
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Affiliation(s)
- Lucia Gigli
- Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino 50019, Italy
- Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino 50019, Italy
- Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine (CIRMMP), Sesto Fiorentino 50019, Italy
| | - José Malanho Silva
- Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino 50019, Italy
- Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino 50019, Italy
- Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine (CIRMMP), Sesto Fiorentino 50019, Italy
- UCIBIO, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2819-516 Caparica, Portugal
| | - Linda Cerofolini
- Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino 50019, Italy
- Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino 50019, Italy
- Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine (CIRMMP), Sesto Fiorentino 50019, Italy
| | - Anjos L Macedo
- UCIBIO, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2819-516 Caparica, Portugal
- Associate Laboratory i4HB─Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2819-516 Caparica, Portugal
| | - Carlos F G C Geraldes
- Department of Life Sciences, Faculty of Science and Technology, 3000-393 Coimbra, Portugal
- Coimbra Chemistry Center─Institute of Molecular Sciences (CCC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal
| | | | - Vito Calderone
- Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino 50019, Italy
- Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino 50019, Italy
- Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine (CIRMMP), Sesto Fiorentino 50019, Italy
| | - Marco Fragai
- Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino 50019, Italy
- Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino 50019, Italy
- Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine (CIRMMP), Sesto Fiorentino 50019, Italy
| | - Giacomo Parigi
- Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino 50019, Italy
- Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino 50019, Italy
- Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine (CIRMMP), Sesto Fiorentino 50019, Italy
| | - Enrico Ravera
- Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino 50019, Italy
- Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino 50019, Italy
- Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine (CIRMMP), Sesto Fiorentino 50019, Italy
- Florence Data Science, University of Florence, Florence 50134, Italy
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino 50019, Italy
- Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino 50019, Italy
- Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine (CIRMMP), Sesto Fiorentino 50019, Italy
- Giotto Biotech, S.R.L., Sesto Fiorentino 50019, Italy
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2
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Nagelski AL, Ozerov M, Fataftah MS, Krzystek J, Greer SM, Holland PL, Telser J. Electronic Structure of Three-Coordinate Fe II and Co II β-Diketiminate Complexes. Inorg Chem 2024; 63:4511-4526. [PMID: 38408452 DOI: 10.1021/acs.inorgchem.3c03388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
The β-diketiminate supporting group, [ArNCRCHCRNAr]-, stabilizes low coordination number complexes. Four such complexes, where R = tert-butyl, Ar = 2,6-diisopropylphenyl, are studied: (nacnactBu)ML, where M = FeII, CoII and L = Cl, CH3. These are denoted FeCl, FeCH3, CoCl, and CoCH3 and have been previously reported and structurally characterized. The two FeII complexes (S = 2) have also been previously characterized by Mössbauer spectroscopy, but only indirect assessment of the ligand-field splitting and zero-field splitting (zfs) parameters was available. Here, EPR spectroscopy is used, both conventional field-domain for the CoII complexes (with S = 3/2) and frequency-domain, far-infrared magnetic resonance spectroscopy (FIRMS) for all four complexes. The CoII complexes were also studied by magnetometry. These studies allow accurate determination of the zfs parameters. The two FeII complexes are similar with nearly axial zfs and large magnitude zfs given by D = -37 ± 1 cm-1 for both. The two CoII complexes likewise exhibit large and nearly axial zfs, but surprisingly, CoCl has positive D = +55 cm-1 while CoCH3 has negative D = -49 cm-1. Theoretical methods were used to probe the electronic structures of the four complexes, which explain the experimental spectra and the zfs parameters.
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Affiliation(s)
- Alexandra L Nagelski
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
| | - Mykhaylo Ozerov
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Majed S Fataftah
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
| | - J Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Samuel M Greer
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Patrick L Holland
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
| | - Joshua Telser
- Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605, United States
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3
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Franzke YJ, Bruder F, Gillhuber S, Holzer C, Weigend F. Paramagnetic Nuclear Magnetic Resonance Shifts for Triplet Systems and Beyond with Modern Relativistic Density Functional Methods. J Phys Chem A 2024; 128:670-686. [PMID: 38195394 DOI: 10.1021/acs.jpca.3c07093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
An efficient framework for the calculation of paramagnetic NMR (pNMR) shifts within exact two-component (X2C) theory and (current-dependent) density functional theory (DFT) up to the class of local hybrid functionals (LHFs) is presented. Generally, pNMR shifts for systems with more than one unpaired electron depend on the orbital shielding contribution and a temperature-dependent term. The latter includes zero-field splitting (ZFS), hyperfine coupling (HFC), and the g-tensor. For consistency, we calculate these three tensors at the same level of theory, i.e., using scalar-relativistic X2C augmented with spin-orbit perturbation theory. Results for pNMR chemical shifts of transition-metal complexes reveal that this X2C-DFT framework can yield good results for both the shifts and the individual tensor contributions of metallocenes and related systems, especially if the HFC constant is large. For small HFC constants, the relative error is often large, and sometimes the sign may be off. 4d and 5d complexes with more complicated structures demonstrate the limitations of a fully DFT-based approach. Additionally, a Co-based complex with a very large ZFS and pronounced multireference character is not well described. Here, a hybrid DFT-multireference framework is necessary for accurate results. Our results show that X2C is sufficient to describe relativistic effects and computationally cheaper than a fully relativistic approach. Thus, it allows use of large basis sets for converged HFCs. Overall, current-dependent meta-generalized gradient approximations and LHFs show some potential; however, the currently available functionals leave a lot to be desired, and the predictive power is limited.
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Affiliation(s)
- Yannick J Franzke
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany
| | - Florian Bruder
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany
| | - Sebastian Gillhuber
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, 76131 Karlsruhe, Germany
| | - Christof Holzer
- Institute of Theoretical Solid State Physics, Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Straße 1, 76131 Karlsruhe, Germany
| | - Florian Weigend
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany
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Pérez AL, Kemmerer A, Zapata AJ, Sartoris R, Gonzalez PJ, Urteaga R, Baggio R, Suarez S, Ramos CA, Dalosto SD, Rizzi AC, Brondino CD. Synthesis, structure, and characterisation of a ferromagnetically coupled dinuclear complex containing Co(II) ions in a high spin configuration and thiodiacetate and phenanthroline as ligands and of a series of isomorphous heterodinuclear complexes containing different Co : Zn ratios. Dalton Trans 2023; 52:14595-14605. [PMID: 37786344 DOI: 10.1039/d3dt02115g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
We report the synthesis, crystal structure, and characterisation of a dinuclear Co(II) compound with thiodiacetate (tda) and phenanthroline (phen) as ligands (1), and of a series of metal complexes isomorphous to 1 with different Co : Zn ratios (2, 4 : 1; 3, 1 : 1; 4, 1 : 4; 5, 1 : 10). General characterisation methodologies and X-ray data showed that all the synthesised complexes are isomorphous to Zn(II) and Cu(II) analogues (CSD codes: DUHXEL and BEBQII). 1 consists of centrosymmetric Co(II) ion dimers in which the ions are 3.214 Å apart, linked by two μ-O bridges. Each cobalt atom is in a distorted octahedral environment of the N2O3S type. UV-vis spectra of 1 and 5 are in line with high spin (S = 3/2) Co(II) ions in octahedral coordination and indicate that the electronic structure of both Co(II) ions in the dinuclear unit does not significantly change relative to that of the magnetically isolated Co(II) ion. EPR spectra of powder samples of 5 (Co : Zn ratio of 1 : 10) together with spectral simulation indicated high spin Co(II) ions with high rhombic distortion of the zfs [E/D = 0.31(1), D > 0]. DC magnetic susceptibility experiments on 1 and analysis of the data constraining the E/D value obtained by EPR yielded g = 2.595(7), |D| = 61(1) cm-1, and an intradimer ferromagnetic exchange coupling of J = 1.39(4) cm-1. EPR spectra as a function of Co : Zn ratio for both powder and single crystal samples confirmed that they result from two effective S' = 1/2 spins that interact through dipolar and isotropic exchange interactions to yield magnetically isolated S' = 1 centres and that interdimeric exchange interactions, putatively mediated by hydrophobic interactions between phen moieties, are negligible. The latter observation contrasts with that observed in the Cu(II) analogue, where a transition from S = 1 to S' = 1/2 was observed. Computational calculations indicated that the absence of the interdimeric exchange interaction in 1 is due to a lower Co(II) ion spin density delocalisation towards the metal ligands.
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Affiliation(s)
- Ana L Pérez
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral and CONICET, Ciudad Universitaria, S3000ZAA Santa Fe, Argentina.
- Instituto de Física del Litoral, Universidad Nacional del Litoral - CONICET, Güemes 3450, 3000 Santa Fe, Argentina
| | - Axel Kemmerer
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral and CONICET, Ciudad Universitaria, S3000ZAA Santa Fe, Argentina.
| | - Alejandro J Zapata
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral and CONICET, Ciudad Universitaria, S3000ZAA Santa Fe, Argentina.
| | - Rosana Sartoris
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral and CONICET, Ciudad Universitaria, S3000ZAA Santa Fe, Argentina.
| | - Pablo J Gonzalez
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral and CONICET, Ciudad Universitaria, S3000ZAA Santa Fe, Argentina.
| | - Raul Urteaga
- Instituto de Física del Litoral, Universidad Nacional del Litoral - CONICET, Güemes 3450, 3000 Santa Fe, Argentina
- Facultad de Ingeniería Química, Universidad Nacional del Litoral, Santiago del Estero 2829, 3000 Santa Fe, Argentina
| | - Ricardo Baggio
- Gerencia de Investigación y Aplicaciones, Centro Atómico Constituyentes, Comisión Nacional de Energía Atómica, Buenos Aires, Argentina
| | - Sebastián Suarez
- Gerencia de Investigación y Aplicaciones, Centro Atómico Constituyentes, Comisión Nacional de Energía Atómica, Buenos Aires, Argentina
| | - Carlos A Ramos
- Instituto de Nanociencia y Nanotecnología, CNEA-CONICET, Centro Atómico Bariloche, 8400, San Carlos de Bariloche, Río Negro, Argentina
| | - Sergio D Dalosto
- Instituto de Física del Litoral, Universidad Nacional del Litoral - CONICET, Güemes 3450, 3000 Santa Fe, Argentina
- Facultad de Ingeniería Química, Universidad Nacional del Litoral, Santiago del Estero 2829, 3000 Santa Fe, Argentina
| | - Alberto C Rizzi
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral and CONICET, Ciudad Universitaria, S3000ZAA Santa Fe, Argentina.
| | - Carlos D Brondino
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral and CONICET, Ciudad Universitaria, S3000ZAA Santa Fe, Argentina.
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5
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Kumarage ND, Marts AR, Grindle MP, Kaine JC, Crandall LA, Chen WY, Ziegler CJ, Tierney DL. Field- and Temperature-Dependent Paramagnetic Relaxation Enhancements in Co(II) Trispyrazolylmethanes. Inorg Chem 2023; 62:15952-15962. [PMID: 37725578 DOI: 10.1021/acs.inorgchem.3c02028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/21/2023]
Abstract
A comprehensive field- and temperature-dependent examination of nuclear magnetic resonance paramagnetic relaxation enhancements (PREs) for the constitutive protons of [Co(Tpm)2][BF4]2 is presented. Data for an apically substituted derivative clearly establish that bis-Tpm complexes of Co(II) undergo Jahn-Teller dynamics about the molecular threefold axis. PREs from the parent Tpm complex were used to numerically extract the electron relaxation times (T1e). The Tpm complex showed field-dependent behavior, with an approximately 40% higher activation barrier than the related trispyrazolylborate (Tp) complex, based on fits to the T1e vs T, B0 data. Analysis of the field-dependent line widths revealed a surprisingly large contribution from susceptibility (Curie) relaxation (20-35% at the highest field), and a molecular radius (9.5 Å) that is consistent with a tightly associated counterion slowing rotation in solution. Density functional theory showed a shared vibration that is consistent with the Jahn-Teller and appears proportionately higher in energy in [Co(Tpm)2]2+. Complete active-space self-consistent field calculations support ascribing electron relaxation to enhanced mixing of the two Eg orbital sets that accompanies the tetragonal distortion and the differences in electron correlation times to the higher Jahn-Teller activation barrier in [Co(Tpm)2]2+.
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Affiliation(s)
- Nuwanthika D Kumarage
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Amy R Marts
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Matthew P Grindle
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Joshua C Kaine
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
| | - Laura A Crandall
- Department of Chemistry, University of Akron, Akron, Ohio 44325, United States
| | - Wei-Yuan Chen
- Department of Chemistry, University of Akron, Akron, Ohio 44325, United States
| | | | - David L Tierney
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
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6
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Bacon AM, Tomlinson W, Hooper JP, Zdilla MJ. Titanium(II) as a Fuel Atom in Energetic Materials. Inorg Chem 2023. [PMID: 37267586 DOI: 10.1021/acs.inorgchem.2c04367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The energetic content of the compounds MgTp2, FeTp2, MnTp2, and TiTp2 is measured by bomb calorimetry and compared to theoretical calculations (Tp = trispyrazoylborate). TiTp2 had the largest heat of combustion of the four compounds. Comparison of the heat of combustion of the Ti complex to those of Mg and Mn complexes suggests an effective combustion energy of TiII of between 1400 and 3000 kJ/mol, affirming the role of TiII as a strong fuel atom.
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Affiliation(s)
- Alexandra M Bacon
- Department of Chemistry, Temple University, 1901 N. 13th St., Philadelphia, Pennsylvania 19122, United States
| | - Warren Tomlinson
- Department of Physics, Naval Postgraduate School, 833 Dyer Rd., Monterey, California 93943, United States
| | - Joseph P Hooper
- Department of Physics, Naval Postgraduate School, 833 Dyer Rd., Monterey, California 93943, United States
| | - Michael J Zdilla
- Department of Chemistry, Temple University, 1901 N. 13th St., Philadelphia, Pennsylvania 19122, United States
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7
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Devkota L, SantaLucia DJ, Wheaton AM, Pienkos AJ, Lindeman SV, Krzystek J, Ozerov M, Berry JF, Telser J, Fiedler AT. Spectroscopic and Magnetic Studies of Co(II) Scorpionate Complexes: Is There a Halide Effect on Magnetic Anisotropy? Inorg Chem 2023; 62:5984-6002. [PMID: 37000941 DOI: 10.1021/acs.inorgchem.2c04468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
Abstract
The observation of single-molecule magnetism in transition-metal complexes relies on the phenomenon of zero-field splitting (ZFS), which arises from the interplay of spin-orbit coupling (SOC) with ligand-field-induced symmetry lowering. Previous studies have demonstrated that the magnitude of ZFS in complexes with 3d metal ions is sometimes enhanced through coordination with heavy halide ligands (Br and I) that possess large free-atom SOC constants. In this study, we systematically probe this "heavy-atom effect" in high-spin cobalt(II)-halide complexes supported by substituted hydrotris(pyrazol-1-yl)borate ligands (TptBu,Me and TpPh,Me). Two series of complexes were prepared: [CoIIX(TptBu,Me)] (1-X; X = F, Cl, Br, and I) and [CoIIX(TpPh,Me)(HpzPh,Me)] (2-X; X = Cl, Br, and I), where HpzPh,Me is a monodentate pyrazole ligand. Examination with dc magnetometry, high-frequency and -field electron paramagnetic resonance, and far-infrared magnetic spectroscopy yielded axial (D) and rhombic (E) ZFS parameters for each complex. With the exception of 1-F, complexes in the four-coordinate 1-X series exhibit positive D-values between 10 and 13 cm-1, with no dependence on halide size. The five-coordinate 2-X series exhibit large and negative D-values between -60 and -90 cm-1. Interpretation of the magnetic parameters with the aid of ligand-field theory and ab initio calculations elucidated the roles of molecular geometry, ligand-field effects, and metal-ligand covalency in controlling the magnitude of ZFS in cobalt-halide complexes.
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Ravera E, Gigli L, Suturina EA, Calderone V, Fragai M, Parigi G, Luchinat C. A High-Resolution View of the Coordination Environment in a Paramagnetic Metalloprotein from its Magnetic Properties. Angew Chem Int Ed Engl 2021; 60:14960-14966. [PMID: 33595173 DOI: 10.1002/anie.202101149] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Indexed: 12/13/2022]
Abstract
Metalloproteins constitute a significant fraction of the proteome of all organisms and their characterization is critical for both basic sciences and biomedical applications. A large portion of metalloproteins bind paramagnetic metal ions, and paramagnetic NMR spectroscopy has been widely used in their structural characterization. However, the signals of nuclei in the immediate vicinity of the metal center are often broadened beyond detection. In this work, we show that it is possible to determine the coordination environment of the paramagnetic metal in the protein at a resolution inaccessible to other techniques. Taking the structure of a diamagnetic analogue as a starting point, a geometry optimization is carried out by fitting the pseudocontact shifts obtained from first principles quantum chemical calculations to the experimental ones.
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Affiliation(s)
- Enrico Ravera
- Magnetic Resonance Center (CERM), University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy.,Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
| | - Lucia Gigli
- Magnetic Resonance Center (CERM), University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy.,Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
| | | | - Vito Calderone
- Magnetic Resonance Center (CERM), University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy.,Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
| | - Marco Fragai
- Magnetic Resonance Center (CERM), University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy.,Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
| | - Giacomo Parigi
- Magnetic Resonance Center (CERM), University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy.,Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM), University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy.,Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
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9
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Ravera E, Gigli L, Suturina EA, Calderone V, Fragai M, Parigi G, Luchinat C. A High‐Resolution View of the Coordination Environment in a Paramagnetic Metalloprotein from its Magnetic Properties. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202101149] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Enrico Ravera
- Magnetic Resonance Center (CERM) University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP) Via L. Sacconi 6 50019 Sesto Fiorentino Italy
- Department of Chemistry “Ugo Schiff” University of Florence Via della Lastruccia 3 50019 Sesto Fiorentino Italy
| | - Lucia Gigli
- Magnetic Resonance Center (CERM) University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP) Via L. Sacconi 6 50019 Sesto Fiorentino Italy
- Department of Chemistry “Ugo Schiff” University of Florence Via della Lastruccia 3 50019 Sesto Fiorentino Italy
| | | | - Vito Calderone
- Magnetic Resonance Center (CERM) University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP) Via L. Sacconi 6 50019 Sesto Fiorentino Italy
- Department of Chemistry “Ugo Schiff” University of Florence Via della Lastruccia 3 50019 Sesto Fiorentino Italy
| | - Marco Fragai
- Magnetic Resonance Center (CERM) University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP) Via L. Sacconi 6 50019 Sesto Fiorentino Italy
- Department of Chemistry “Ugo Schiff” University of Florence Via della Lastruccia 3 50019 Sesto Fiorentino Italy
| | - Giacomo Parigi
- Magnetic Resonance Center (CERM) University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP) Via L. Sacconi 6 50019 Sesto Fiorentino Italy
- Department of Chemistry “Ugo Schiff” University of Florence Via della Lastruccia 3 50019 Sesto Fiorentino Italy
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM) University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP) Via L. Sacconi 6 50019 Sesto Fiorentino Italy
- Department of Chemistry “Ugo Schiff” University of Florence Via della Lastruccia 3 50019 Sesto Fiorentino Italy
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10
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Müller L, Nadurata VL, Cula B, Hoof S, Herwig C, Limberg C. Versatile Coordination Behavior of the Asymmetric Bis(3‐mesityl‐pyrazol‐1‐yl)(5‐mesitylpyrazol‐1‐yl) Hydroborate Ligand towards Late 3 d M
2+
Ions. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Lars Müller
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Vincent L. Nadurata
- School of Chemistry University of Melbourne Parkville Victoria 3010 Australia
| | - Beatrice Cula
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Santina Hoof
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Christian Herwig
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Christian Limberg
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
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11
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An electrochemical study of cobalt-salen (N,N′-bis(salicylidene)ethylenediaminocobalt(II) in the oxidation of syringyl alcohol in acetonitrile. J APPL ELECTROCHEM 2020. [DOI: 10.1007/s10800-020-01459-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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12
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Pavlov AA, Nehrkorn J, Zubkevich SV, Fedin MV, Holldack K, Schnegg A, Novikov VV. A Synergy and Struggle of EPR, Magnetometry and NMR: A Case Study of Magnetic Interaction Parameters in a Six-Coordinate Cobalt(II) Complex. Inorg Chem 2020; 59:10746-10755. [DOI: 10.1021/acs.inorgchem.0c01191] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Alexander A. Pavlov
- A.N.Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, Moscow 119991, Russia
- Moscow Institute of Physics and Technology,
Institutskiy per. 9, Dolgoprudny, Moscow 141701, Russia
| | - Joscha Nehrkorn
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
| | | | - Matvey V. Fedin
- International Tomography Center, SB RAS, Institutskaya
3A, Novosibirsk 630090, Russia
- Novosibirsk State University, Novosibirsk 630090, Russia
| | - Karsten Holldack
- Helmholtz-Zentrum für Materialien und Energie GmbH (HZB), Albert-Einstein-Straße 15, D-12489 Berlin, Germany
| | - Alexander Schnegg
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34−36, 45470 Mülheim an der Ruhr, Germany
| | - Valentin V. Novikov
- A.N.Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, Moscow 119991, Russia
- Moscow Institute of Physics and Technology,
Institutskiy per. 9, Dolgoprudny, Moscow 141701, Russia
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13
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Pyykkönen A, Feher R, Köhler FH, Vaara J. Paramagnetic Pyrazolylborate Complexes Tp 2M and Tp* 2M: 1H, 13C, 11B, and 14N NMR Spectra and First-Principles Studies of Chemical Shifts. Inorg Chem 2020; 59:9294-9307. [PMID: 32558559 DOI: 10.1021/acs.inorgchem.0c01176] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The paramagnetic pyrazolylborates Tp2M and Tp*2M (M = Cu, Ni, Co, Fe, Mn, Cr, V) as well as [Tp2M]+ and [Tp*2M]+ (M = Fe, Cr, V) have been synthesized and their NMR spectra recorded. The 1H signal shift ranges vary from ∼30 ppm (Cu(II) and V(III)) to ∼220 ppm (Co(II)), and the 13C signal shift ranges from ∼180 ppm (Fe(III)) to ∼1150 ppm (Cr(II)). The 11B and 14N shifts are ∼360 and ∼730 ppm, respectively. Both negative and positive shifts have been observed for all nuclei. The narrow NMR signals of the Co(II), Fe(II), Fe(III), and V(III) derivatives provide resolved 13C,1H couplings. All chemical shifts have been calculated from first-principles on a modern version of Kurland-McGarvey theory which includes optimized structures, zero-field splitting, and g tensors, as well as signal shift contributions. Temperature dependence in the Fe(II) spin-crossover complex results from the equilibrium of the ground singlet and the excited quintet. We illustrate both the assignment and analysis capabilities, as well as the shortcomings of the current computational methodology.
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Affiliation(s)
- Ari Pyykkönen
- NMR Research Unit, University of Oulu, P.O. Box 3000, Oulu FI-90014, Finland
| | - Robert Feher
- Department Chemie, Technische Universität München, D-85748 Garching, Germany
| | - Frank H Köhler
- Department Chemie, Technische Universität München, D-85748 Garching, Germany
| | - Juha Vaara
- NMR Research Unit, University of Oulu, P.O. Box 3000, Oulu FI-90014, Finland
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14
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Seredyuk M, Znovjyak K, Fritsky IO, Sliva TY, Slobodyanik MS. Crystal structure and magnetic properties of bis[butyltris(1 H-pyrazol-1-yl)borato]iron(II). Acta Crystallogr E Crystallogr Commun 2019; 75:1327-1330. [PMID: 31523459 PMCID: PMC6727041 DOI: 10.1107/s2056989019011137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 08/09/2019] [Indexed: 11/16/2022]
Abstract
The title compound, bis[butyltris(1H-pyrazol-1-yl)borato]iron(II), belongs to the class of neutral scorpionate complexes. The crystal structure at low temperature and the magnetic susceptibility measurement in the high-temperature region reveal the low-spin character of the iron(II) ion. The asymmetric unit of the title compound, [Fe(C13H18BN6)2], contains two half independent complex molecules. In each complex, the FeII atom is located on an inversion center and is surrounded by two scorpionate ligand butyltris(1H-pyrazol-1-yl)borate molecules that coordinate to the iron(II) ion through the N atoms of the pyrazole groups. The two independent complex molecules differ essentially in the conformation of the butyl substituents. In the crystal, the complex molecules are linked by a series of C—H⋯π interactions, which generate a supramolecular three-dimensional structure. At 120 K, the average Fe—N bond distance is 1.969 Å, indicating the low-spin state of the iron(II) atom, which does not change upon heating, as demonstrated by high-temperature magnetic susceptibility measurements.
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15
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De S, Flambard A, Garnier D, Herson P, Köhler FH, Mondal A, Costuas K, Gillon B, Lescouëzec R, Le Guennic B, Gendron F. Probing the Local Magnetic Structure of the [Fe
III
(Tp)(CN)
3
]
−
Building Block Via Solid‐State NMR Spectroscopy, Polarized Neutron Diffraction, and First‐Principle Calculations. Chemistry 2019; 25:12120-12136. [DOI: 10.1002/chem.201902239] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 06/27/2019] [Indexed: 11/06/2022]
Affiliation(s)
- Siddhartha De
- Institut Parisien de Chimie Moléculaire, CNRS UMR 8232Sorbonne Université 4 place Jussieu 75252 Paris cedex 5 France
| | - Alexandrine Flambard
- Institut Parisien de Chimie Moléculaire, CNRS UMR 8232Sorbonne Université 4 place Jussieu 75252 Paris cedex 5 France
| | - Delphine Garnier
- Institut Parisien de Chimie Moléculaire, CNRS UMR 8232Sorbonne Université 4 place Jussieu 75252 Paris cedex 5 France
| | - Patrick Herson
- Institut Parisien de Chimie Moléculaire, CNRS UMR 8232Sorbonne Université 4 place Jussieu 75252 Paris cedex 5 France
| | - Frank H. Köhler
- Technische Universität München Lichtenbergstrasse 4 85747 Garching Germany
| | - Abhishake Mondal
- Institut Parisien de Chimie Moléculaire, CNRS UMR 8232Sorbonne Université 4 place Jussieu 75252 Paris cedex 5 France
| | - Karine Costuas
- Univ Rennes, CNRS, Institut des Sciences Chimiques de Rennes (ISCR), UMR 6226 35000 Rennes France
| | - Béatrice Gillon
- Laboratoire Léon Brillouin, CEA and CNRS, UMR 12Centre d'Etudes de Saclay 91191 Gif-sur-Yvette France
| | - Rodrigue Lescouëzec
- Institut Parisien de Chimie Moléculaire, CNRS UMR 8232Sorbonne Université 4 place Jussieu 75252 Paris cedex 5 France
| | - Boris Le Guennic
- Univ Rennes, CNRS, Institut des Sciences Chimiques de Rennes (ISCR), UMR 6226 35000 Rennes France
| | - Frédéric Gendron
- Univ Rennes, CNRS, Institut des Sciences Chimiques de Rennes (ISCR), UMR 6226 35000 Rennes France
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16
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Diego R, Pavlov A, Darawsheh M, Aleshin D, Nehrkorn J, Nelyubina Y, Roubeau O, Novikov V, Aromí G. Coordination [Co II2] and [Co IIZn II] Helicates Showing Slow Magnetic Relaxation. Inorg Chem 2019; 58:9562-9566. [PMID: 31283191 DOI: 10.1021/acs.inorgchem.9b01334] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The slow magnetic relaxation of CoII ions in the elusive intermediate geometry between the trigonal prism and antiprism has been studied on the new [Co2L3]4+ and [CoZnL3]4+ coordination helicates [L is a bis(pyrazolylpyridine) ligand]. Solution paramagnetic 1H NMR and solid-state magnetization measurements unveil single-molecule-magnet behavior with small axial anisotropy, as predicted previously.
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Affiliation(s)
- Rosa Diego
- Departament de Química Inorgànica i Orgànica , Universitat de Barcelona , Diagonal 645 , 08028 Barcelona , Spain.,Institute of Nanoscience and Nanotechnology of the Unirvesity of Barcelona (IN2UB) , Barcelona , Spain
| | - Alexander Pavlov
- A. N. Nesmeyanov Institute of Organoelement Compounds , Russian Academy of Sciences , Vavilova strasse 28 , Moscow , Russia.,Moscow Institute of Physics and Technology , Institutskiy per. 9, Dolgoprudny, Moscow , Russia
| | - Mohanad Darawsheh
- Departament de Química Inorgànica i Orgànica , Universitat de Barcelona , Diagonal 645 , 08028 Barcelona , Spain
| | - Dmitry Aleshin
- A. N. Nesmeyanov Institute of Organoelement Compounds , Russian Academy of Sciences , Vavilova strasse 28 , Moscow , Russia.,Mendeleev University of Chemical Technology of Russia , Miusskaya sq. 9 , 125047 Moscow , Russia
| | - Joscha Nehrkorn
- Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36 , 45470 Mülheim an der Ruhr , Germany
| | - Yulia Nelyubina
- A. N. Nesmeyanov Institute of Organoelement Compounds , Russian Academy of Sciences , Vavilova strasse 28 , Moscow , Russia.,Moscow Institute of Physics and Technology , Institutskiy per. 9, Dolgoprudny, Moscow , Russia
| | - Olivier Roubeau
- Instituto de Ciencia de Materiales de Aragón (ICMA) , CSIC and Universidad de Zaragoza , 50009 Zaragoza , Spain
| | - Valentin Novikov
- A. N. Nesmeyanov Institute of Organoelement Compounds , Russian Academy of Sciences , Vavilova strasse 28 , Moscow , Russia.,Moscow Institute of Physics and Technology , Institutskiy per. 9, Dolgoprudny, Moscow , Russia
| | - Guillem Aromí
- Departament de Química Inorgànica i Orgànica , Universitat de Barcelona , Diagonal 645 , 08028 Barcelona , Spain.,Institute of Nanoscience and Nanotechnology of the Unirvesity of Barcelona (IN2UB) , Barcelona , Spain
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17
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Krzystek J, Kohl G, Hansen HB, Enders M, Telser J. Combining HFEPR and NMR Spectroscopies to Characterize Organochromium(III) Complexes with Large Zero-Field Splitting. Organometallics 2019. [DOI: 10.1021/acs.organomet.9b00158] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- J. Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Gerald Kohl
- Institute of Inorganic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
| | - Helge-Boj Hansen
- Institute of Inorganic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
| | - Markus Enders
- Institute of Inorganic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
| | - Joshua Telser
- Department of Biological, Physical and Health Sciences, Roosevelt University, 430 S. Michigan Avenue, Chicago, Illinois 60605, United States
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18
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Nishiura T, Uramoto T, Takiyama Y, Nakazawa J, Hikichi S. Cobalt(II) Complexes with N, N, N-Scorpionates and Bidentate Ligands: Comparison of Hydrotris(3,5-dimethylpyrazol-1-yl)borate Tp* vs. Phenyltris(4,4-dimethyloxazolin-2-yl)borate To M to Control the Structural Properties and Reactivities of Cobalt Centers. Molecules 2018; 23:E1466. [PMID: 29914171 PMCID: PMC6099786 DOI: 10.3390/molecules23061466] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 06/13/2018] [Accepted: 06/15/2018] [Indexed: 11/16/2022] Open
Abstract
Scorpionate ligands Tp* (hydrotris(3,5-dimethylpyrazol-1-yl)borate) and ToM (tris(4,4-dimethyloxazolin-2-yl)phenylborate) complexes of cobalt(II) with bidentate ligands were synthesized. Both Tp* and ToM coordinate to cobalt(II) in a tridentate fashion when the bidentate ligand is the less hindered acetylacetonate. In crystal structures, the geometry of cobalt(II) supported by the N₃O₂ donor set in the Tp* complex is a square-pyramid, whereas that in the ToM complex is close to a trigonal-bipyramid. Both Tp*- and ToM-acac complexes exhibit solvatochromic behavior, although the changing structural equilibria of these complexes in MeCN are quite different. In the bis(1-methylimidazol-2-yl)methylphenylborate (LPh) complexes, Tp* retains the tridentate (к³) mode, whereas ToM functions as the bidentate (к²) ligand, giving the tetrahedral cobalt(II) complex. The bowl-shaped cavity derived from the six methyl groups on ToM lead to susceptibility to the bulkiness of the opposite bidentate ligand. The entitled scorpionate compounds mediate hydrocarbon oxidation with organic peroxides. Allylic oxidation of cyclohexene occurs mainly on the reaction with tert-butyl hydroperoxide (TBHP), although the catalytic efficiency of the scorpionate ligand complexes is lower than that of Co(OAc)₂ and Co(acac)₂. On cyclohexane oxidation with meta-chloroperbenzoic acid (mCPBA), both ToM and Tp* complexes function as catalysts for hydroxylation. The higher electron-donating ToM complexes show faster initial reaction rates compared to the corresponding Tp* complexes.
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Affiliation(s)
- Toshiki Nishiura
- Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama 221-8686, Japan.
| | - Takahiro Uramoto
- Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama 221-8686, Japan.
| | - Yuichiro Takiyama
- Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama 221-8686, Japan.
| | - Jun Nakazawa
- Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama 221-8686, Japan.
| | - Shiro Hikichi
- Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawa-ku, Yokohama 221-8686, Japan.
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19
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Scaldini FM, Ramalho Freitas MC, De Souza Reis M, Yoshida MI, Krambrock K, Machado FC. A Co(ii) 1D coordination polymer constructed from 1,3-bisbenzyl-2-oxoimidazoline-4,5-dicarboxylic acid: crystal structure and magnetic properties. NEW J CHEM 2018. [DOI: 10.1039/c7nj04564f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new complex involving 1,3-bisbenzyl-2-oxoimidazoline-4,5-dicarboxylic acid (H2L) and a cobalt(ii) metal ion designated [Co(L)(H2O)2]n has been synthesized under solvothermal conditions and characterized.
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Affiliation(s)
- Felipe Mageste Scaldini
- Departamento de Química
- Instituto de Ciências Exatas
- Universidade Federal de Juiz de Fora
- Juiz de Fora-MG
- Brazil
| | | | | | - Maria Irene Yoshida
- Departamento de Química
- Instituto de Ciências Exatas
- Universidade Federal de Minas Gerais
- Belo Horizonte-MG
- Brazil
| | - Klaus Krambrock
- Departamento de Física
- Instituto de Ciências Exatas
- Universidade Federal de Minas Gerais
- Belo Horizonte-MG
- Brazil
| | - Flávia Cavalieri Machado
- Departamento de Química
- Instituto de Ciências Exatas
- Universidade Federal de Juiz de Fora
- Juiz de Fora-MG
- Brazil
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20
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Gendron F, Bolvin H, Autschbach J. Complete Active Space Wavefunction-Based Analysis of Magnetization and Electronic Structure. TOP ORGANOMETAL CHEM 2018. [DOI: 10.1007/3418_2018_6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
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21
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Dubey RJC, Comito RJ, Wu Z, Zhang G, Rieth AJ, Hendon CH, Miller JT, Dincă M. Highly Stereoselective Heterogeneous Diene Polymerization by Co-MFU-4l: A Single-Site Catalyst Prepared by Cation Exchange. J Am Chem Soc 2017; 139:12664-12669. [DOI: 10.1021/jacs.7b06841] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Romain J.-C. Dubey
- Department
of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Robert J. Comito
- Department
of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Zhenwei Wu
- Davidson
School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - Guanghui Zhang
- Davidson
School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - Adam J. Rieth
- Department
of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Christopher H. Hendon
- Department
of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Jeffrey T. Miller
- Davidson
School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - Mircea Dincă
- Department
of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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22
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Marts AR, Kaine JC, Baum RR, Clayton VL, Bennett JR, Cordonnier LJ, McCarrick R, Hasheminasab A, Crandall LA, Ziegler CJ, Tierney DL. Paramagnetic Resonance of Cobalt(II) Trispyrazolylmethanes and Counterion Association. Inorg Chem 2016; 56:618-626. [PMID: 27977149 DOI: 10.1021/acs.inorgchem.6b02520] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Paramagnetic resonance studies (EPR, ESEEM, ENDOR, and NMR) of a series of cobalt(II) bis-trispyrazolylmethane tetrafluoroborates are presented. The complexes studied include the parent, unsubstituted ligand (Tpm), two pyrazole-substituted derivatives (4Me and 3,5-diMe), and tris(1-pyrazolyl)ethane (Tpe), which includes a methyl group on the apical carbon atom. NMR and ENDOR establish the magnitude of 1H hyperfine couplings, while ESEEM provides information on the coordinated 14N. The data show that the pyrazole 3-position is more electron rich in the Tpm analogues, that the geometry about the apical atom influences the magnetic resonance, and that apical atom geometry appears more fixed in Tpm than in Tp. NMR and ENDOR establish that the BF4- counterion remains associated in fluid solution. In the case of the Tpm3,5Me complex, it appears to associate in solution, in the same position it occupies in the X-ray structure.
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Affiliation(s)
- Amy R Marts
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Joshua C Kaine
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Robert R Baum
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Vivien L Clayton
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Jami R Bennett
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Laura J Cordonnier
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Robert McCarrick
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Abed Hasheminasab
- Department of Chemistry, University of Akron , Akron, Ohio 44325, United States
| | - Laura A Crandall
- Department of Chemistry, University of Akron , Akron, Ohio 44325, United States
| | | | - David L Tierney
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
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23
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Garnier D, Jiménez JR, Li Y, von Bardeleben J, Journaux Y, Augenstein T, Moos EMB, Gamer MT, Breher F, Lescouëzec R. K⊂{[Fe II(Tp)(CN) 3] 4[Co III( pzTp)] 3[Co II( pzTp)]}: a neutral soluble model complex of photomagnetic Prussian blue analogues. Chem Sci 2016; 7:4825-4831. [PMID: 30155130 PMCID: PMC6014070 DOI: 10.1039/c6sc01435f] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 05/13/2016] [Indexed: 11/25/2022] Open
Abstract
Straightforward access to a new cyanide-bridged {Fe4Co4} "molecular box" containing a potassium ion, namely K⊂{[FeII(Tp)(CN)3]4[CoIII(pzTp)]3[CoII(pzTp)]} (1) (with Tp and pzTp = tris- and tetrakis(pyrazolyl)borate, respectively), is provided, alongside its full characterisation. A detailed analysis of the molecular structure (X-ray diffraction, mass spectrometry, NMR spectroscopy) and electronic properties (EPR spectroscopy, SQUID magnetometry, UV/Vis spectroscopy, cyclic voltammetry) reveals that 1 shows slow magnetic relaxation and a remarkable photomagnetic effect at low temperature which is reminiscent of some FeCo Prussian Blue Analogues (PBAs), and is ascribed to a photo-induced electron transfer. However, in contrast with these inorganic polymers, the overall neutral compound 1 is soluble and remarkably stable in organic solvents such as CH2Cl2. Moreover, 1 shows interesting redox versatility, with electrochemical experiments revealing the possible access to six stable redox states.
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Affiliation(s)
- D Garnier
- Institute of Inorganic Chemistry , Karlsruhe Institute of Technology (KIT) , Engesserstr. 15, Geb. 30.45 , D-76131 Karlsruhe , Germany .
- Institut Parisien de Chimie Moléculaire - CNRS UMR 8232 , UPMC - Paris 6 , Sorbonne Universités , 4 place Jussieu , F-75252 Paris cedex 05 , France .
| | - J-R Jiménez
- Institut Parisien de Chimie Moléculaire - CNRS UMR 8232 , UPMC - Paris 6 , Sorbonne Universités , 4 place Jussieu , F-75252 Paris cedex 05 , France .
| | - Y Li
- Institut Parisien de Chimie Moléculaire - CNRS UMR 8232 , UPMC - Paris 6 , Sorbonne Universités , 4 place Jussieu , F-75252 Paris cedex 05 , France .
| | - J von Bardeleben
- Institut des Nanosciences de Paris - CNRS UMR 7588 , UPMC - Paris 6 , Sorbonne Universités , 4 place Jussieu , F-75252 Paris cedex 05 , France
| | - Y Journaux
- Institut Parisien de Chimie Moléculaire - CNRS UMR 8232 , UPMC - Paris 6 , Sorbonne Universités , 4 place Jussieu , F-75252 Paris cedex 05 , France .
| | - T Augenstein
- Institute of Inorganic Chemistry , Karlsruhe Institute of Technology (KIT) , Engesserstr. 15, Geb. 30.45 , D-76131 Karlsruhe , Germany .
| | - E M B Moos
- Institute of Inorganic Chemistry , Karlsruhe Institute of Technology (KIT) , Engesserstr. 15, Geb. 30.45 , D-76131 Karlsruhe , Germany .
| | - M T Gamer
- Institute of Inorganic Chemistry , Karlsruhe Institute of Technology (KIT) , Engesserstr. 15, Geb. 30.45 , D-76131 Karlsruhe , Germany .
| | - F Breher
- Institute of Inorganic Chemistry , Karlsruhe Institute of Technology (KIT) , Engesserstr. 15, Geb. 30.45 , D-76131 Karlsruhe , Germany .
| | - R Lescouëzec
- Institut Parisien de Chimie Moléculaire - CNRS UMR 8232 , UPMC - Paris 6 , Sorbonne Universités , 4 place Jussieu , F-75252 Paris cedex 05 , France .
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24
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Fliedel C, Rosa V, Vileno B, Parizel N, Choua S, Gourlaouen C, Rosa P, Turek P, Braunstein P. Zwitterionic Cobalt Complexes with Bis(diphenylphosphino)(N-thioether)amine Assembling Ligands: Structural, EPR, Magnetic, and Computational Studies. Inorg Chem 2016; 55:4183-98. [PMID: 27054464 DOI: 10.1021/acs.inorgchem.5b02889] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The coordination of two heterofunctional P,P,S ligands of the N-functionalized DPPA-type bearing an alkylthioether or arylthioether N-substituent, (Ph2P)2N(CH2)3SMe (1) and (Ph2P)2N(p-C6H4)SMe (2), respectively, toward cobalt dichloride was investigated to examine the influence of the linker between the PNP nitrogen and the S atoms. The complexes [CoCl2(1)]2 (3) and [CoCl2(2)]2 (4) have been isolated, and 3 was shown by X-ray diffraction to be a unique dinuclear, zwitterion containing one CoCl moiety bis-chelated by two ligands 1 and one CoCl3 fragment coordinated by the S atom of a thioether function. The FT-IR, UV-vis, and EPR spectroscopic features of 3 were analyzed as the superposition of those of constitutive fragments identified by a retrosynthetic-type analysis. A similar approach provided insight into the nature of 4 for which no X-ray diffraction data could be obtained. A comparison between the spectroscopic features of 4 and of its constitutive fragments, [CoCl(2)2]PF6 (7) and [H2']2[CoCl4] (8) (2' = NH2(p-C6H4)SMe), and between those of 4 and 3 suggested that 4 could either have a zwitterionic structure, similar to that of 3, or contain a tetrahedral dicationic bis-chelated Co center associated with a CoCl4 dianion. Magnetic and EPR studies and theoretical calculations were performed. Doublet spin states were found for the pentacoordinated complexes [CoCl(1)2]PF6 (5) and 7 and anisotropic quadruplet spin states for the tetrahedral complexes [CoCl3(H1')] (6) (1' = NH2(CH2)3SMe) and 8. A very similar behavior was observed for 3 and 4, consisting in the juxtaposition of noninteracting doublet and quadruplet spin states. Antiferromagnetic interactions explain the formation of dimers for 6 and of layers for 8. The EPR signatures of 3 and 4 correspond to the superposition of low-spin nuclei in 5 and 7 and high-spin nuclei in 6 and 8, respectively. From DFT calculations, the solid-state structure of 4 appears best described as zwitterionic, with a low-spin state for the Co1 atom.
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Affiliation(s)
| | | | - Bertrand Vileno
- French EPR Federation of Research (REseau NAtional de Rpe interDisciplinaire, RENARD), Fédération IR-RPE CNRS 3443, 67081 Strasbourg, France
| | | | | | | | - Patrick Rosa
- CNRS, Université de Bordeaux, ICMCB , UPR9048, F-33600 Pessac, France
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25
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Baum RR, Myers WK, Greer SM, Breece RM, Tierney DL. The Original CoII Heteroscorpionates Revisited: On the EPR of Pseudotetrahedral CoII. Eur J Inorg Chem 2016. [DOI: 10.1002/ejic.201501356] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Robert R. Baum
- Department of Chemistry and BiochemistryMiami University45056OxfordOHUSA
| | - William K. Myers
- Department of Chemistry and BiochemistryMiami University45056OxfordOHUSA
| | - Samuel M. Greer
- Department of Chemistry and BiochemistryMiami University45056OxfordOHUSA
| | - Robert M. Breece
- Department of Chemistry and BiochemistryMiami University45056OxfordOHUSA
| | - David L. Tierney
- Department of Chemistry and BiochemistryMiami University45056OxfordOHUSA
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26
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Werner TW, Reschke S, Bunzen H, von Nidda HAK, Deisenhofer J, Loidl A, Volkmer D. [Co5Tp*4(Me2bta)6]: A Highly Symmetrical Pentanuclear Kuratowski Complex Featuring Tris(pyrazolyl)borate and Benzotriazolate Ligands. Inorg Chem 2016; 55:1053-60. [DOI: 10.1021/acs.inorgchem.5b01982] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tamas W. Werner
- Chair of Solid State and Materials Chemistry,
Institute of Physics, University of Augsburg, Universitaetsstrasse 1, D-86159 Augsburg, Germany
| | - Stephan Reschke
- Experimental Physics V, Center for Electronic Correlations
and Magnetism, Institute of Physics, University of Augsburg, Universitaetsstrasse
1, D-86159 Augsburg, Germany
| | - Hana Bunzen
- Chair of Solid State and Materials Chemistry,
Institute of Physics, University of Augsburg, Universitaetsstrasse 1, D-86159 Augsburg, Germany
| | - Hans-Albrecht Krug von Nidda
- Experimental Physics V, Center for Electronic Correlations
and Magnetism, Institute of Physics, University of Augsburg, Universitaetsstrasse
1, D-86159 Augsburg, Germany
| | - Joachim Deisenhofer
- Experimental Physics V, Center for Electronic Correlations
and Magnetism, Institute of Physics, University of Augsburg, Universitaetsstrasse
1, D-86159 Augsburg, Germany
| | - Alois Loidl
- Experimental Physics V, Center for Electronic Correlations
and Magnetism, Institute of Physics, University of Augsburg, Universitaetsstrasse
1, D-86159 Augsburg, Germany
| | - Dirk Volkmer
- Chair of Solid State and Materials Chemistry,
Institute of Physics, University of Augsburg, Universitaetsstrasse 1, D-86159 Augsburg, Germany
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27
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Kadel LR, Bullinger JR, Baum RR, Moore CE, Tierney DL, Eichhorn DM. Cyanoscorpionate Ligands: Agostic Interactions in a Series of Metal Complexes Containing the Tris(4‐cyano‐3‐phenylpyrazolyl)borate and Bis(4‐cyano‐3‐phenylpyrazolyl)borate Ligands. Eur J Inorg Chem 2016. [DOI: 10.1002/ejic.201501268] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Lava R. Kadel
- Department of ChemistryWichita State University67260WichitaKSUSA
| | | | - Robert R. Baum
- Department of Chemistry and BiochemistryMiami University45056SAOxfordOHUSA
| | - Curtis E. Moore
- Department of Chemistry and BiochemistryUniversity of CaliforniaSan DiegoCAUSA
| | - David L. Tierney
- Department of Chemistry and BiochemistryMiami University45056SAOxfordOHUSA
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28
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Li J, Han Y, Cao F, Wei RM, Zhang YQ, Song Y. Two field-induced slow magnetic relaxation processes in a mononuclear Co(ii) complex with a distorted octahedral geometry. Dalton Trans 2016; 45:9279-84. [DOI: 10.1039/c6dt00979d] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An easy-axis distorted octahedral mononuclear Co(ii) single-molecule magnet showing two filed-induced slow magnetic relaxation processes.
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Affiliation(s)
- Jing Li
- State Key Laboratory of Coordination Chemistry
- Collaborative Innovation Center of Advanced Mirostructures
- School of Chemistry and Chemical Engineering
- Nanjing University
- Nanjing 210093
| | - Yuan Han
- State Key Laboratory of Coordination Chemistry
- Collaborative Innovation Center of Advanced Mirostructures
- School of Chemistry and Chemical Engineering
- Nanjing University
- Nanjing 210093
| | - Fan Cao
- State Key Laboratory of Coordination Chemistry
- Collaborative Innovation Center of Advanced Mirostructures
- School of Chemistry and Chemical Engineering
- Nanjing University
- Nanjing 210093
| | - Rong-Min Wei
- State Key Laboratory of Coordination Chemistry
- Collaborative Innovation Center of Advanced Mirostructures
- School of Chemistry and Chemical Engineering
- Nanjing University
- Nanjing 210093
| | - Yi-Quan Zhang
- Jiangsu Key Laboratory for NSLSCS
- School of Physical Science and Technology
- Nanjing Normal University
- Nanjing 210023
- China
| | - You Song
- State Key Laboratory of Coordination Chemistry
- Collaborative Innovation Center of Advanced Mirostructures
- School of Chemistry and Chemical Engineering
- Nanjing University
- Nanjing 210093
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29
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Forshaw AP, Smith JM, Ozarowski A, Krzystek J, Smirnov D, Zvyagin SA, Harris TD, Karunadasa HI, Zadrozny JM, Schnegg A, Holldack K, Jackson TA, Alamiri A, Barnes DM, Telser J. Low-Spin Hexacoordinate Mn(III): Synthesis and Spectroscopic Investigation of Homoleptic Tris(pyrazolyl)borate and Tris(carbene)borate Complexes. Inorg Chem 2012; 52:144-59. [DOI: 10.1021/ic301630d] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Adam P. Forshaw
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003, United
States
| | - Jeremy M. Smith
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003, United
States
| | - Andrew Ozarowski
- National High Magnetic
Field Laboratory (NHMFL), Florida State University, Tallahassee, Florida 32310, United States
| | - J. Krzystek
- National High Magnetic
Field Laboratory (NHMFL), Florida State University, Tallahassee, Florida 32310, United States
| | - Dmitry Smirnov
- National High Magnetic
Field Laboratory (NHMFL), Florida State University, Tallahassee, Florida 32310, United States
| | - S. A. Zvyagin
- Dresden High Magnetic Field Laboratory (HLD), Helmholtz-Zentrum Dresden-Rossendorf, D-01314
Dresden, Germany
| | - T. David Harris
- Department
of Chemistry, Northwestern University,
Evanston, Illinois 60208, United States
| | | | - Joseph M. Zadrozny
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Alexander Schnegg
- Helmholtz-Zentrum für Materialien
und Energie, Institut für Silizium-Photovoltaik, D-12489 Berlin, Germany
| | - Karsten Holldack
- Helmholtz-Zentrum für Materialien und Energie, Institut für Methoden und Instrumente der Forschung mit Synchrotronstrahlung, D-12489 Berlin, Germany
| | - Timothy A. Jackson
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
| | - Ahmad Alamiri
- Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605, United
States
| | - Diane M. Barnes
- Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605, United
States
| | - Joshua Telser
- Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605, United
States
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30
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Liang S, Wang H, Deb T, Petersen JL, Yee GT, Jensen MP. Structural and Spectroscopic Trends in a Series of Half-Sandwich Scorpionate Complexes. Inorg Chem 2012; 51:12707-19. [DOI: 10.1021/ic301409s] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Shengwen Liang
- Department of Chemistry and
Biochemistry, Ohio University, Athens,
Ohio 45701, United States
| | - Haoshuang Wang
- Department of Chemistry and
Biochemistry, Ohio University, Athens,
Ohio 45701, United States
| | - Tapash Deb
- Department of Chemistry and
Biochemistry, Ohio University, Athens,
Ohio 45701, United States
| | - Jeffrey L. Petersen
- C. Eugene Bennett Department
of Chemistry, West Virginia University,
Morgantown, West Virginia 26506, United States
| | - Gordon T. Yee
- Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg,
Virginia 24061, United States
| | - Michael P. Jensen
- Department of Chemistry and
Biochemistry, Ohio University, Athens,
Ohio 45701, United States
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31
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Tierney DL. Jahn-Teller dynamics in a series of high-symmetry Co(II) chelates determine paramagnetic relaxation enhancements. J Phys Chem A 2012; 116:10959-72. [PMID: 23095055 DOI: 10.1021/jp309245e] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
NMR paramagnetic relaxation enhancements (PREs) of a series of structurally characterized, trigonal bis-trispyrazolylborate (Tp) chelates of high-spin Co(II), spanning 100-850 MHz in field, are reported. Prior knowledge of the metal-nucleus distances allows numerical extraction of position-dependent electron spin relaxation rates (τ(c)(-1)) from direct measurement of the individual PREs of the four symmetry distinct protons in Co(Tp)(2), using available closed-form expressions. The data for this electronically complex system where spin-orbit coupling defines the ground state electronic structure are analyzed in terms of the Solomon-Bloembergen-Morgan (SBM) relations, as well as available zero-field splitting limit theories. A simple angular correction is shown to be sufficient to reconcile the individual τ(c)(T) data for the four classes of protons. The data identify a previously unrecognized dynamic Jahn-Teller effect in these historically important complexes, with a barrier of ~230 cm(-1), pointing to a level of dynamics in trispyrazolylborate chemistry that has not been described before, and further show that it is the Jahn-Teller that is responsible for the PREs in fluid solution. A field-dependent component is also identified for the two protons nearest g(//), which is suggested to arise due to Zeeman mixing of excited state character into the ground level.
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Affiliation(s)
- David L Tierney
- Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, New Mexico 87131, United States.
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32
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Oseback SN, Shim SW, Kumar M, Greer SM, Gardner SR, Lemar KM, DeGregory PR, Papish ET, Tierney DL, Zeller M, Yap GPA. Crowded bis ligand complexes of TtzPh,Me with first row transition metals rearrange due to ligand field effects: structural and electronic characterization (TtzPh,Me = tris(3-phenyl-5-methyl-1,2,4-triazolyl)borate). Dalton Trans 2012; 41:2774-87. [DOI: 10.1039/c2dt12029a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Shannon N Oseback
- Departments of Chemistry, Drexel University, Philadelphia, PA 19104, USA
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33
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Fielding AJ, Kovaleva EG, Farquhar ER, Lipscomb JD, Que L. A hyperactive cobalt-substituted extradiol-cleaving catechol dioxygenase. J Biol Inorg Chem 2011; 16:341-55. [PMID: 21153851 PMCID: PMC3192431 DOI: 10.1007/s00775-010-0732-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Accepted: 10/27/2010] [Indexed: 11/27/2022]
Abstract
Homoprotocatechuate 2,3-dioxygenase from Brevibacterium fuscum (HPCD) has an Fe(II) center in its active site that can be replaced with Mn(II) or Co(II). Whereas Mn-HPCD exhibits steady-state kinetic parameters comparable to those of Fe-HPCD, Co-HPCD behaves somewhat differently, exhibiting significantly higher [Formula: see text] and k (cat). The high activity of Co-HPCD is surprising, given that cobalt has the highest standard M(III/II) redox potential of the three metals. Comparison of the X-ray crystal structures of the resting and substrate-bound forms of Fe-HPCD, Mn-HPCD, and Co-HPCD shows that metal substitution has no effect on the local ligand environment, the conformational integrity of the active site, or the overall protein structure, suggesting that the protein structure does not differentially tune the potential of the metal center. Analysis of the steady-state kinetics of Co-HPCD suggests that the Co(II) center alters the relative rate constants for the interconversion of intermediates in the catalytic cycle but still allows the dioxygenase reaction to proceed efficiently. When compared with the kinetic data for Fe-HPCD and Mn-HPCD, these results show that dioxygenase catalysis can proceed at high rates over a wide range of metal redox potentials. This is consistent with the proposed mechanism in which the metal mediates electron transfer between the catechol substrate and O(2) to form the postulated [M(II)(semiquinone)superoxo] reactive species. These kinetic differences and the spectroscopic properties of Co-HPCD provide new tools with which to explore the unique O(2) activation mechanism associated with the extradiol dioxygenase family.
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Affiliation(s)
- Andrew J Fielding
- Department of Chemistry, Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant Street, Minneapolis, MN 55455, USA
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34
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Krzystek J, Swenson DC, Zvyagin SA, Smirnov D, Ozarowski A, Telser J. Cobalt(II) “Scorpionate” Complexes as Models for Cobalt-Substituted Zinc Enzymes: Electronic Structure Investigation by High-Frequency and -Field Electron Paramagnetic Resonance Spectroscopy. J Am Chem Soc 2010; 132:5241-53. [PMID: 20329727 DOI: 10.1021/ja910766w] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- J. Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, Dresden High Magnetic Field Laboratory (HLD), Forschungszentrum Dresden-Rossendorf, D-01314 Dresden, Germany, and Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605
| | - Dale C. Swenson
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, Dresden High Magnetic Field Laboratory (HLD), Forschungszentrum Dresden-Rossendorf, D-01314 Dresden, Germany, and Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605
| | - S. A. Zvyagin
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, Dresden High Magnetic Field Laboratory (HLD), Forschungszentrum Dresden-Rossendorf, D-01314 Dresden, Germany, and Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605
| | - Dmitry Smirnov
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, Dresden High Magnetic Field Laboratory (HLD), Forschungszentrum Dresden-Rossendorf, D-01314 Dresden, Germany, and Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, Dresden High Magnetic Field Laboratory (HLD), Forschungszentrum Dresden-Rossendorf, D-01314 Dresden, Germany, and Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605
| | - Joshua Telser
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, Dresden High Magnetic Field Laboratory (HLD), Forschungszentrum Dresden-Rossendorf, D-01314 Dresden, Germany, and Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605
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35
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Myers WK, Scholes CP, Tierney DL. Anisotropic Fermi couplings due to large unquenched orbital angular momentum: Q-band (1)H, (14)N, and (11)B ENDOR of bis(trispyrazolylborate) cobalt(II). J Am Chem Soc 2009; 131:10421-9. [PMID: 19591466 DOI: 10.1021/ja900866y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report Q-band ENDOR of (1)H, (14)N, and (11)B at the g( parallel) extreme of the EPR spectrum of bis(trispyrazolylborate) cobalt(II) [Co(Tp)(2)] and two structural analogs. This trigonally symmetric, high-spin (hs) S = 3/2 Co(II) complex shows large unquenched ground-state orbital angular momentum, which leads to highly anisotropic electronic g-values (g( parallel) = 8.48, g( perpendicular) = 1.02). The large g-anisotropy is shown to result in large dipolar couplings near g( parallel) and uniquely anisotropic (14)N Fermi couplings, which arise from spin transferred to the nitrogen 2s orbital (2.2%) via antibonding interactions with singly occupied metal d(x(2)-y(2)) and d(z(2)) orbitals. Large, well-resolved (1)H and (11)B dipolar couplings were also observed. Taken in concert with our previous X-band ENDOR measurements at g( perpendicular) ( Myers, W. K.; et al. Inorg. Chem. 2008, 47, 6701-6710 ), the present data allow a detailed analysis of the dipolar hyperfine tensors of two of the four symmetry distinct protons in the parent molecule. In the substituted analogs, changes in hyperfine coupling due to altered metal-proton distances give further evidence of an anisotropic Fermi contact interaction. For the pyrazolyl 3H proton, the data indicate a 0.2 MHz anisotropic contact interaction and approximately 4% transfer of spin away from Co(II). Dipolar coupling also dominates for the axial boron atoms, consistent with their distance from the Co(II) ion, and resolved (11)B quadrupolar coupling showed approximately 30% electronic inequivalence between the B-H and B-C sp(3) bonds. This is the first comprehensive ENDOR study of any hs Co(II) species and lays the foundation for future development.
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Affiliation(s)
- William K Myers
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA
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36
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Kuzu I, Krummenacher I, Hewitt I, Lan Y, Mereacre V, Powell AK, Höfer P, Harmer J, Breher F. Syntheses, Structures and Electronic Properties of Zwitterionic Iron(II) and Cobalt(II) Complexes Featuring Ambidentate Tris(pyrazolyl)methanide Ligands. Chemistry 2009; 15:4350-65. [DOI: 10.1002/chem.200802317] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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