1
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Killian MM, Brophy MB, Nolan EM, Brunold TC. Spectroscopic and computational investigations of Cobalt(II) binding to the innate immune protein human calprotectin. J Biol Inorg Chem 2024; 29:127-137. [PMID: 38233645 DOI: 10.1007/s00775-023-02034-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 10/30/2023] [Indexed: 01/19/2024]
Abstract
Human calprotectin (CP) is an innate immune protein that participates in the metal-withholding response to infection by sequestering essential metal nutrients from invading microbial pathogens. CP is comprised of S100A8 (α subunit, 10.8 kDa) and S100A9 (β subunit, 13.2 kDa). Two transition-metal binding sites of CP form at the S100A8/S100A9 dimer interface. Site 1 is a His3Asp motif comprised of His83 and His87 from the S100A8 subunit and His20 and Asp30 from the S100A9 subunit. Site 2 is an unusual hexahistidine motif composed of S100A8 residues His17 and His27 and S100A9 residues His91, His95, His103, and His105. In the present study, the His3Asp and His6 sites of CP were further characterized by utilizing Co2+ as a spectroscopic probe. Magnetic circular dichroism spectroscopy was employed in conjunction with electron paramagnetic resonance spectroscopy and density functional theory computations to characterize the Co2+-bound S100A8(C42S)/S100A9(C3S) CP-Ser variant and six site variants that allowed the His3Asp and His6 sites to be further probed. Our results provide new insight into the metal-binding sites of CP-Ser and the effect of amino acid substitutions on the structure of site 2.
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Affiliation(s)
- Michelle M Killian
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Megan B Brophy
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Elizabeth M Nolan
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
| | - Thomas C Brunold
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA.
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2
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Bhatt G, Sharma T, Gupta SK, Meyer F, Rajaraman G, Murugavel R. Tuning Magnetic Anisotropy in Co(II) Tetrahedral Carbazole-Modified Phosphine Oxide Single-Ion Magnets: Importance of Structural Distortion versus Heavy-Ion Effect. Inorg Chem 2023; 62:18915-18925. [PMID: 37947449 DOI: 10.1021/acs.inorgchem.3c02401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Three mononuclear cobalt(II) tetrahedral complexes [Co(CzPh2PO)2X2] (CzPh2PO = (9H-carbazol-9-yl)diphenylphosphine oxide and X = Cl (1), Br (2), I (3)) have been synthesized using a simple synthetic approach to examine their single-ion magnetic (SIM) behavior. A detailed study of the variation in the dynamic magnetic properties of the Co(II) ion in a tetrahedral ligand field has been carried out by the change of the halide ligand. The axial zero-field splitting parameter D was found to vary from -16.4 cm-1 in 1 to -13.8 cm-1 in 2 and +14.6 cm-1 in 3. All the new complexes exhibit field-induced SIM behavior. The results obtained from ab initio CASSF calculations match well with the experimental data, revealing how halide ions induce a change in the D value as we move from Cl- to I-. The ab initio calculations further reveal that the change in the sign of D is due to the multideterminant characteristics of the ground state wave function of 1 and 2, while single-determinant characteristics are instead observed for 3. To gain a better understanding of the relationship between the structural distortion and the sign and magnitude of D values, magnetostructural D correlations were developed using angular relationships, revealing the importance of structural distortions over the heavy halide effect in controlling the sign of D values. This study broadens the scope of employing electronically and sterically modified phosphine oxide ligands in building new types of air-stable Co(II) SIMs.
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Affiliation(s)
- Gargi Bhatt
- Department of Chemistry, Indian Institute of Technology Bombay, Powai 400076, Mumbai, India
| | - Tanu Sharma
- Department of Chemistry, Indian Institute of Technology Bombay, Powai 400076, Mumbai, India
| | - Sandeep K Gupta
- University of Göttingen, Institute of Inorganic Chemistry, Göttingen D-37077, Germany
| | - Franc Meyer
- University of Göttingen, Institute of Inorganic Chemistry, Göttingen D-37077, Germany
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Powai 400076, Mumbai, India
| | - Ramaswamy Murugavel
- Department of Chemistry, Indian Institute of Technology Bombay, Powai 400076, Mumbai, India
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3
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Du W, Gao F, Cui P, Yu Z, Tong W, Wang J, Ren Z, Song C, Xu J, Ma H, Dang L, Zhang D, Lu Q, Jiang J, Wang J, Pi L, Sheng Z, Lu Q. Twisting, untwisting, and retwisting of elastic Co-based nanohelices. Nat Commun 2023; 14:4426. [PMID: 37481654 PMCID: PMC10363140 DOI: 10.1038/s41467-023-40001-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 07/07/2023] [Indexed: 07/24/2023] Open
Abstract
The reversible transformation of a nanohelix is one of the most exquisite and important phenomena in nature. However, nanomaterials usually fail to twist into helical crystals. Considering the irreversibility of the previously studied twisting forces, the reverse process (untwisting) is more difficult to achieve, let alone the retwisting of the untwisted crystalline nanohelices. Herein, we report a new reciprocal effect between molecular geometry and crystal structure which triggers a twisting-untwisting-retwisting cycle for tri-cobalt salicylate hydroxide hexahydrate. The twisting force stems from competition between the condensation reaction and stacking process, different from the previously reported twisting mechanisms. The resulting distinct nanohelices give rise to unusual structure elasticity, as reflected in the reversible change of crystal lattice parameters and the mutual transformation between the nanowires and nanohelices. This study proposes a fresh concept for designing reversible processes and brings a new perspective in crystallography.
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Affiliation(s)
- Wei Du
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing National Laboratory of Microstructures, Nanjing University, 210023, Nanjing, P. R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, 211816, Nanjing, P. R. China
| | - Feng Gao
- Department of Materials Science and Engineering, Jiangsu Key Laboratory of Artificial Functional Materials, Collaborative Innovation Center of Advanced Microstructures, College of Engineering and Applied Science, Nanjing University, 210023, Nanjing, P. R. China.
| | - Peng Cui
- Hefei National Laboratory for Physical Sciences at Microscale and Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, 230026, Hefei, AnHui, P. R. China
| | - Zhiwu Yu
- High Magnetic Field Laboratory, CAS Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, 230031, Hefei, Anhui, P. R. China
| | - Wei Tong
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory and High Magnetic Field Laboratory of Anhui Province, HFIPS, Chinese Academy of Sciences, 230031, Hefei, Anhui, P. R. China
| | - Jihao Wang
- Hefei National Laboratory for Physical Sciences at Microscale and Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, 230026, Hefei, AnHui, P. R. China
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory and High Magnetic Field Laboratory of Anhui Province, HFIPS, Chinese Academy of Sciences, 230031, Hefei, Anhui, P. R. China
| | - Zhuang Ren
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory and High Magnetic Field Laboratory of Anhui Province, HFIPS, Chinese Academy of Sciences, 230031, Hefei, Anhui, P. R. China
| | - Chuang Song
- Department of Materials Science and Engineering, Jiangsu Key Laboratory of Artificial Functional Materials, Collaborative Innovation Center of Advanced Microstructures, College of Engineering and Applied Science, Nanjing University, 210023, Nanjing, P. R. China
| | - Jiaying Xu
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing National Laboratory of Microstructures, Nanjing University, 210023, Nanjing, P. R. China
| | - Haifeng Ma
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing National Laboratory of Microstructures, Nanjing University, 210023, Nanjing, P. R. China
| | - Liyun Dang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing National Laboratory of Microstructures, Nanjing University, 210023, Nanjing, P. R. China
| | - Di Zhang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing National Laboratory of Microstructures, Nanjing University, 210023, Nanjing, P. R. China
| | - Qingyou Lu
- Hefei National Laboratory for Physical Sciences at Microscale and Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, 230026, Hefei, AnHui, P. R. China.
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory and High Magnetic Field Laboratory of Anhui Province, HFIPS, Chinese Academy of Sciences, 230031, Hefei, Anhui, P. R. China.
| | - Jun Jiang
- Hefei National Laboratory for Physical Sciences at Microscale and Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, 230026, Hefei, AnHui, P. R. China.
| | - Junfeng Wang
- High Magnetic Field Laboratory, CAS Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, 230031, Hefei, Anhui, P. R. China.
| | - Li Pi
- Hefei National Laboratory for Physical Sciences at Microscale and Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, 230026, Hefei, AnHui, P. R. China
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory and High Magnetic Field Laboratory of Anhui Province, HFIPS, Chinese Academy of Sciences, 230031, Hefei, Anhui, P. R. China
| | - Zhigao Sheng
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory and High Magnetic Field Laboratory of Anhui Province, HFIPS, Chinese Academy of Sciences, 230031, Hefei, Anhui, P. R. China
| | - Qingyi Lu
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing National Laboratory of Microstructures, Nanjing University, 210023, Nanjing, P. R. China.
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4
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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: 4] [Impact Index Per Article: 4.0] [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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5
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Ferentinos E, Tzeli D, Sottini S, Groenen EJJ, Ozerov M, Poneti G, Kaniewska-Laskowska K, Krzystek J, Kyritsis P. Magnetic anisotropy and structural flexibility in the field-induced single ion magnets [Co{(OPPh 2)(EPPh 2)N} 2], E = S, Se, explored by experimental and computational methods. Dalton Trans 2023; 52:2036-2050. [PMID: 36692040 PMCID: PMC9926333 DOI: 10.1039/d2dt03335f] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 01/14/2023] [Indexed: 01/25/2023]
Abstract
During the last few years, a large number of mononuclear Co(II) complexes of various coordination geometries have been explored as potential single ion magnets (SIMs). In the work presented herein, the Co(II) S = 3/2 tetrahedral [Co{(OPPh2)(EPPh2)N}2], E = S, Se, complexes (abbreviated as CoO2E2), bearing chalcogenated mixed donor-atom imidodiphosphinato ligands, were studied by both experimental and computational techniques. Specifically, direct current (DC) magnetometry provided estimations of their zero-field splitting (zfs) axial (D) and rhombic (E) parameter values, which were more accurately determined by a combination of far-infrared magnetic spectroscopy and high-frequency and -field EPR spectroscopy studies. The latter combination of techniques was also implemented for the S = 3/2 tetrahedral [Co{(EPiPr2)2N}2], E = S, Se, complexes, confirming the previously determined magnitude of their zfs parameters. For both pairs of complexes (E = S, Se), it is concluded that the identity of the E donor atom does not significantly affect their zfs parameters. High-resolution multifrequency EPR studies of CoO2E2 provided evidence of multiple conformations, which are more clearly observed for CoO2Se2, in agreement with the structural disorder previously established for this complex by X-ray crystallography. The CoO2E2 complexes were shown to be field-induced SIMs, i.e., they exhibit slow relaxation of magnetization in the presence of an external DC magnetic field. Advanced quantum-chemical calculations on CoO2E2 provided additional insight into their electronic and structural properties.
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Affiliation(s)
- Eleftherios Ferentinos
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, GR-15771 Athens, Greece.
| | - Demeter Tzeli
- Physical Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, GR-15771 Athens, Greece
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., GR-11635 Athens, Greece
| | - Silvia Sottini
- Huygens-Kamerlingh Onnes Laboratory, Department of Physics, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands
| | - Edgar J J Groenen
- Huygens-Kamerlingh Onnes Laboratory, Department of Physics, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands
| | - Mykhaylo Ozerov
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA.
| | - Giordano Poneti
- Instituto de Química, Universidade Federal do Rio de Janeiro, 21941-909 Rio de Janeiro, Brazil.
| | - Kinga Kaniewska-Laskowska
- Department of Inorganic Chemistry, Faculty of Chemistry, Gdańsk University of Technology, G. Narutowicza St. 11/12, Gdańsk PL-80-233, Poland
| | - J Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA.
| | - Panayotis Kyritsis
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, GR-15771 Athens, Greece.
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6
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Maurice R, Mallah T, Guihéry N. Magnetism in Binuclear Compounds: Theoretical Insights. TOP ORGANOMETAL CHEM 2023. [DOI: 10.1007/3418_2022_78] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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7
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Moseley DH, Liu Z, Bone AN, Stavretis SE, Singh SK, Atanasov M, Lu Z, Ozerov M, Thirunavukkuarasu K, Cheng Y, Daemen LL, Lubert-Perquel D, Smirnov D, Neese F, Ramirez-Cuesta AJ, Hill S, Dunbar KR, Xue ZL. Comprehensive Studies of Magnetic Transitions and Spin-Phonon Couplings in the Tetrahedral Cobalt Complex Co(AsPh 3) 2I 2. Inorg Chem 2022; 61:17123-17136. [PMID: 36264658 DOI: 10.1021/acs.inorgchem.2c02604] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A combination of inelastic neutron scattering (INS), far-IR magneto-spectroscopy (FIRMS), and Raman magneto-spectroscopy (RaMS) has been used to comprehensively probe magnetic excitations in Co(AsPh3)2I2 (1), a reported single-molecule magnet (SMM). With applied field, the magnetic zero-field splitting (ZFS) peak (2D') shifts to higher energies in each spectroscopy. INS placed the ZFS peak at 54 cm-1, as revealed by both variable-temperature (VT) and variable-magnetic-field data, giving results that agree well with those from both far-IR and Raman studies. Both FIRMS and RaMS also reveal the presence of multiple spin-phonon couplings as avoided crossings with neighboring phonons. Here, phonons refer to both intramolecular and lattice vibrations. The results constitute a rare case in which the spin-phonon couplings are observed with both Raman-active (g modes) and far-IR-active phonons (u modes; space group P21/c, no. 14, Z = 4 for 1). These couplings are fit using a simple avoided crossing model with coupling constants of ca. 1-2 cm-1. The combined spectroscopies accurately determine the magnetic excited level and the interaction of the magnetic excitation with phonon modes. Density functional theory (DFT) phonon calculations compare well with INS, allowing for the assignment of the modes and their symmetries. Electronic calculations elucidate the nature of ZFS in the complex. Features of different techniques to determine ZFS and other spin-Hamiltonian parameters in transition-metal complexes are summarized.
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Affiliation(s)
- Duncan H Moseley
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee37996, United States
| | - Zhiming Liu
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee37996, United States
| | - Alexandria N Bone
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee37996, United States
| | - Shelby E Stavretis
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee37996, United States
| | - Saurabh Kumar Singh
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, 502285Sangareddy, Telangana, India
| | - Mihail Atanasov
- Max Planck Institute for Coal Research, Kaiser-Wilhelm-Platz 1, D-45470Mülheim an der Ruhr, Germany.,Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 1113Sofia, Bulgaria
| | - Zhengguang Lu
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida32310, United States
| | - Mykhaylo Ozerov
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida32310, United States
| | | | - Yongqiang Cheng
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
| | - Luke L Daemen
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
| | - Daphné Lubert-Perquel
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida32310, United States
| | - Dmitry Smirnov
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida32310, United States
| | - Frank Neese
- Max Planck Institute for Coal Research, Kaiser-Wilhelm-Platz 1, D-45470Mülheim an der Ruhr, Germany
| | - A J Ramirez-Cuesta
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
| | - Stephen Hill
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida32310, United States.,Department of Physics, Florida State University, Tallahassee, Florida32306, United States
| | - Kim R Dunbar
- Department of Chemistry, Texas A&M University, College Station, Texas77843, United States
| | - Zi-Ling Xue
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee37996, United States
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8
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Taylor WV, Cashman BK, Xie ZL, Ngo KK, Rose MJ. Synthesis and Magnetic Properties of Antimony-Ligated Co(II) Complexes: Stibines versus Phosphines. Inorg Chem 2022; 61:6733-6741. [PMID: 35466675 DOI: 10.1021/acs.inorgchem.1c03366] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Herein, we test the hypothesis that neutral, heavy-atom stibine donors can increase the extent of spin-orbit coupling on light, 3d transition metal. To this end, we developed a novel synthetic route toward coordinating a paramagnetic 3d metal ion─cobalt(II)─with neutral stibine ligands. Such complexes have not been reported in the literature due to the weak σ donor strength of stibines and the hard-soft mismatch between a 3d metal and a 5p ligand─which herein has been overcome using alkylated Sb donors. Magnetometry of [(SbiPr2Ph)2Co(I)2] (1) reveals that the stibine complex 1 exhibits a higher magnitude D value (D = |24.96| cm-1) than the spectroscopically derived value for the corresponding phosphine complex 3 (D = -13.13 cm-1), indicative of large zero-field splitting. CASSCF/NEVPT2 calculations corroborate the experimental D values for 1 and 3, predicting D = -31.9 and -8.9 cm-1, respectively. A re-examination of magnetic parameters across the entire series [(ER3)2Co(X)2] (E = P → Sb; X = Cl → I) reveals that (i) increasingly heavy pnictogens lead to an increased X-Co-X bond angle, which is correlated with larger magnitude D values, and (ii) for a given X-Co-X bond angle, the D value is always higher in the presence of a heavy pnictogen as compared with a heavy halide. Ab initio ligand field theory calculations for 1 (stibine complex) and 3 (phosphine complex) reveal no substantial differences in spin-orbit coupling (ζ = 479.2, 480.2 cm-1) or Racah parameter (B = 947.5, 943.9 cm-1), an indicator of covalency. Thus, some "heavy atom effect" on the D value beyond geometric perturbation is operative, but its precise mechanism(s) of action remains obscure.
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Affiliation(s)
- William V Taylor
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78757, United States
| | - Brenna K Cashman
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78757, United States
| | - Zhu-Lin Xie
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78757, United States
| | - Karen K Ngo
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78757, United States
| | - Michael J Rose
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78757, United States
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9
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A high-frequency EPR study of magnetic anisotropy and intermolecular interactions of Co(II) ions. Polyhedron 2021. [DOI: 10.1016/j.poly.2021.115389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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10
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Bone AN, Widener CN, Moseley DH, Liu Z, Lu Z, Cheng Y, Daemen LL, Ozerov M, Telser J, Thirunavukkuarasu K, Smirnov D, Greer SM, Hill S, Krzystek J, Holldack K, Aliabadi A, Schnegg A, Dunbar KR, Xue ZL. Applying Unconventional Spectroscopies to the Single-Molecule Magnets, Co(PPh 3 ) 2 X 2 (X=Cl, Br, I): Unveiling Magnetic Transitions and Spin-Phonon Coupling. Chemistry 2021; 27:11110-11125. [PMID: 33871890 DOI: 10.1002/chem.202100705] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Indexed: 11/11/2022]
Abstract
Large separation of magnetic levels and slow relaxation in metal complexes are desirable properties of single-molecule magnets (SMMs). Spin-phonon coupling (interactions of magnetic levels with phonons) is ubiquitous, leading to magnetic relaxation and loss of memory in SMMs and quantum coherence in qubits. Direct observation of magnetic transitions and spin-phonon coupling in molecules is challenging. We have found that far-IR magnetic spectra (FIRMS) of Co(PPh3 )2 X2 (Co-X; X=Cl, Br, I) reveal rarely observed spin-phonon coupling as avoided crossings between magnetic and u-symmetry phonon transitions. Inelastic neutron scattering (INS) gives phonon spectra. Calculations using VASP and phonopy programs gave phonon symmetries and movies. Magnetic transitions among zero-field split (ZFS) levels of the S=3/2 electronic ground state were probed by INS, high-frequency and -field EPR (HFEPR), FIRMS, and frequency-domain FT terahertz EPR (FD-FT THz-EPR), giving magnetic excitation spectra and determining ZFS parameters (D, E) and g values. Ligand-field theory (LFT) was used to analyze earlier electronic absorption spectra and give calculated ZFS parameters matching those from the experiments. DFT calculations also gave spin densities in Co-X, showing that the larger Co(II) spin density in a molecule, the larger its ZFS magnitude. The current work reveals dynamics of magnetic and phonon excitations in SMMs. Studies of such couplings in the future would help to understand how spin-phonon coupling may lead to magnetic relaxation and develop guidance to control such coupling.
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Affiliation(s)
- Alexandria N Bone
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Chelsea N Widener
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Duncan H Moseley
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Zhiming Liu
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Zhengguang Lu
- National High Magnetic Field Laboratory, Tallahassee, Florida, 32310, USA
| | - Yongqiang Cheng
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - Luke L Daemen
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
| | - Mykhaylo Ozerov
- National High Magnetic Field Laboratory, Tallahassee, Florida, 32310, USA
| | - Joshua Telser
- Department of Biological, Physical and Chemical Sciences, Roosevelt University, Chicago, Illinois, 60605, USA
| | | | - Dmitry Smirnov
- National High Magnetic Field Laboratory, Tallahassee, Florida, 32310, USA
| | - Samuel M Greer
- National High Magnetic Field Laboratory, Tallahassee, Florida, 32310, USA.,Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida, 32306, USA
| | - Stephen Hill
- National High Magnetic Field Laboratory, Tallahassee, Florida, 32310, USA.,Department of Physics, Florida State University, Tallahassee, Florida, 32306, USA
| | - J Krzystek
- National High Magnetic Field Laboratory, Tallahassee, Florida, 32310, USA
| | - Karsten Holldack
- Helmholtz-Zentrum Berlin für Materialien und Energie Gmbh, Institut für Methoden und Instrumente der Forschung mit Synchrotronstrahlung, 12489, Berlin, Germany
| | - Azar Aliabadi
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institut für Nanospektroskopie, Berlin Joint EPR Laboratory, 12489, Berlin, Germany
| | - Alexander Schnegg
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institut für Nanospektroskopie, Berlin Joint EPR Laboratory, 12489, Berlin, Germany.,Max Planck Institute for Chemical Energy Conversion, 45470, Mülheim an der Ruhr, Germany
| | - Kim R Dunbar
- Department of Chemistry, Texas A&M University, College Station, Texas, 77842, USA
| | - Zi-Ling Xue
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee, 37996, USA
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11
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Ostrovsky S, Tomkowicz Z, Foro S, Reedijk J, Haase W. Magneto-optical study of the zero-field splitting in a mononuclear tetrahedrally coordinated Co(II) compound with a mixed ligand surrounding. Polyhedron 2020. [DOI: 10.1016/j.poly.2020.114630] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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12
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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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13
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Mantanona AJ, Tolentino DR, Cay KS, Gembicky M, Jazzar R, Bertrand G, Rinehart JD. Tuning electronic structure through halide modulation of mesoionic carbene cobalt complexes. Dalton Trans 2020; 49:2426-2430. [PMID: 32048665 DOI: 10.1039/c9dt04624k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The first examples of Co(ii) mesoionic carbene complexes (CoX2DippMIC2; X = Cl-, Br-, I-) demonstrate a new electronic perturbation on tetrahedral Co(ii) complexes. Using absorption spectroscopy and magnetometry, the consequences of the MIC's strong σ-donating/minimal π-accepting nature are analyzed and shown to be further tunable by the nature of the coordinated halide.
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Affiliation(s)
- Alex J Mantanona
- Department of Chemistry and Biochemistry, University of California - San Diego, La Jolla, CA 92093, USA.
| | - Daniel R Tolentino
- Department of Chemistry and Biochemistry, University of California - San Diego, La Jolla, CA 92093, USA.
| | - Kristine S Cay
- Department of Chemistry and Biochemistry, University of California - San Diego, La Jolla, CA 92093, USA.
| | - Milan Gembicky
- Department of Chemistry and Biochemistry, University of California - San Diego, La Jolla, CA 92093, USA.
| | - Rodolphe Jazzar
- Department of Chemistry and Biochemistry, University of California - San Diego, La Jolla, CA 92093, USA.
| | - Guy Bertrand
- Department of Chemistry and Biochemistry, University of California - San Diego, La Jolla, CA 92093, USA.
| | - Jeffrey D Rinehart
- Department of Chemistry and Biochemistry, University of California - San Diego, La Jolla, CA 92093, USA.
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14
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Plugis NM, Rudd ND, Krzystek J, Swenson DC, Telser J, Larrabee JA. Cobalt(II) "Scorpionate" complexes as electronic ground state models for cobalt-substituted zinc enzymes: Structure investigation by magnetic circular dichroism. J Inorg Biochem 2019; 203:110876. [PMID: 31756558 DOI: 10.1016/j.jinorgbio.2019.110876] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 09/19/2019] [Accepted: 10/01/2019] [Indexed: 12/15/2022]
Abstract
Zinc centers in pseudo-tetrahedral geometry are widely found in biology, often with three histidine ligands from protein. The trispyrazolylborate "scorpionate" ligand is used as a model for this tris(histidine) motif, and spectroscopically active CoII is often used as a substitute for spectroscopically silent ZnII. In this work, four pseudo-tetrahedral scorpionate complexes with the formula (Tpt-Bu,Tn)CoL, where Tpt-Bu,Tn = hydrotris(3-tert-butyl, 5-2'-thienyl-pyrazol-1-yl)borate anion and L = Cl-, N3-, NCO-, or NCS-, were studied using variable-temperature, variable-field magnetic circular dichroism (VTVH MCD) spectroscopy. The major goal was to determine the axial and rhombic zero field splitting (ZFS) parameters (D and E, respectively) of these S = 3/2 systems and compare these ZFS parameters to those determined previously by high-frequency and -field electron paramagnetic resonance (HFEPR) spectroscopy on the same (L = Cl- and NCS-) or closely related complexes. Additionally, HFEPR studies were undertaken here on the complexes with L = N3-, NCO-. Crystal structures for these two complexes are also first reported here. The values of D determined by VTVH MCD were + 12.8 and + 3.6 cm-1 for the L = Cl- and NCS- complexes, respectively. These values are in close agreement with those for the same complexes as previously determined by HFEPR. The values of D determined by VTVH MCD were + 3.0 and + 6.6 cm-1 for the L = N3- and NCO- complexes, respectively. These values were not as close to those determined by HFEPR in the present study, which are 4.2 cm-1 ≤ |D| ≤ 5.6 cm-1 in Tpt-Bu,TnCoN3, and 8.3 cm-1 ≤ |D| ≤ 11.0 cm-1 in Tpt-Bu,TnCoNCO. The bands in MCD spectra of these complexes were assigned in C3v symmetry and a complete ligand-field analysis of the MCD data was made using the Angular Overlap Model (AOM), which is compared to previous results.
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Affiliation(s)
- Nicholas M Plugis
- Department of Chemistry & Biochemistry, 547 Bicentennial Way, Middlebury College, Middlebury, VT 05753, USA
| | - Nathan D Rudd
- Department of Chemistry & Biochemistry, 547 Bicentennial Way, Middlebury College, Middlebury, VT 05753, USA
| | - J Krzystek
- National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, FL 32310, USA
| | - Dale C Swenson
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Joshua Telser
- Department of Biological, Physical and Health Sciences, Roosevelt University, 430 South Michigan Avenue, Chicago, IL 60605, USA
| | - James A Larrabee
- Department of Chemistry & Biochemistry, 547 Bicentennial Way, Middlebury College, Middlebury, VT 05753, USA.
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15
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Ishizaki T, Fukuda T, Akaki M, Fuyuhiro A, Hagiwara M, Ishikawa N. Synthesis of a Neutral Mononuclear Four-Coordinate Co(II) Complex Having Two Halved Phthalocyanine Ligands That Shows Slow Magnetic Relaxations under Zero Static Magnetic Field. Inorg Chem 2019; 58:5211-5220. [DOI: 10.1021/acs.inorgchem.9b00286] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Toshiharu Ishizaki
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Takamitsu Fukuda
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Mitsuru Akaki
- Center for Advanced High Magnetic Field Science (AHMF), Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Akira Fuyuhiro
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Masayuki Hagiwara
- Center for Advanced High Magnetic Field Science (AHMF), Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Naoto Ishikawa
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
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16
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Antholine WE, Zhang S, Gonzales J, Newman N. Better Resolution of High-Spin Cobalt Hyperfine at Low Frequency: Co-Doped Ba(Zn 1/3Ta 2/3)O₃ as a Model Complex. Int J Mol Sci 2018; 19:ijms19113532. [PMID: 30423944 PMCID: PMC6274703 DOI: 10.3390/ijms19113532] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 11/02/2018] [Accepted: 11/06/2018] [Indexed: 11/30/2022] Open
Abstract
Low-frequency electron paramagnetic resonance (EPR) is used to extract the EPR parameter A-mid and support the approximate X-band value of g-mid for Ba(CoyZn1/3−yTa2/3)O3. Although the cobalt hyperfine structure for the |±1/2〉 state is often unresolved at X-band or S-band, it is resolved in measurements on this compound. This allows for detailed analysis of the molecular orbital for the |±1/2〉 state, which is often the ground state. Moreover, this work shows that the EPR parameters for Co substituted into Zn compounds give important insight into the properties of zinc binding sites.
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Affiliation(s)
- William E Antholine
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
| | - Shengke Zhang
- Materials Program, Arizona State University, Tempe, AZ 85287, USA.
| | - Justin Gonzales
- Materials Program, Arizona State University, Tempe, AZ 85287, USA.
| | - Nathan Newman
- Materials Program, Arizona State University, Tempe, AZ 85287, USA.
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17
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Switlicka A, Machura B, Kruszynski R, Cano J, Toma LM, Lloret F, Julve M. The influence of pseudohalide ligands on the SIM behaviour of four-coordinate benzylimidazole-containing cobalt(ii) complexes. Dalton Trans 2018; 47:5831-5842. [PMID: 29648565 DOI: 10.1039/c7dt04735e] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Three, mononuclear complexes of the formula [Co(bmim)2(SCN)2] (1), [Co(bmim)2(NCO)2] (2) and [Co(bmim)2(N3)2] (3) [bmim = 1-benzyl-2-methylimidazole] were prepared and structurally analyzed by single-crystal X-ray crystallography. The cobalt(ii) ions in 1-3 are tetrahedrally coordinated with two bmim molecules and two pseudohalide anions. The angular distortion parameter δ was calculated and the SHAPE program (based on the CShM concept) was used for 1-3 to estimate the angular distortion from an ideal tetrahedron. The molecules of 1-3 are effectively separated, and the values of the shortest distance of cobalt-cobalt are 8.442(6) and 6.774(8) Å for 1, 10.349(8) and 10.716(8) Å for 2 and 6.778(1) and 9.232(1) Å for 3. Direct current (dc) magnetic susceptibility measurements on the crushed crystals of 1-3 were carried out in the temperature range 1.9-295 K. The variable-temperature magnetic data of 1-3 mainly obey the zero-field splitting effect (D) of the 4A2 ground term of the tetrahedral cobalt(ii) complexes (2D being the energy gap between the |±1/2 and |±3/2 levels of the spin). The analysis of their magnetic data through the Hamiltonian H = D[S2z - S(S + 1)/3] + E(Sx2 - Sy2) + gβHS led to the following best-fit parameters: g = 2.29, D = -7.5 cm-1 and E/D = 0.106 (1), g = 2.28, D = + 6.3 cm-1 and E/D = 0.007 (2) and g = 2.36, D = + 6.7 cm-1 and E/D = 0.090 (3). The signs of D for 1-3 were confirmed by Q-band EPR spectra on powdered samples in the temperature range 4.0-20 K. Field-induced SIM behaviour was observed for 1-3 below 4.0 K, and the frequency-dependent maxima of χ''M were observed for 1 and only incipient signals of χ''M occurred for 2 and 3. The values of the exponential factor (τ0) and activation energy (Ea) for 1-3 which were obtained from the Arrhenius plot suggest a single relaxation process characteristic of an Orbach mechanism.
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Affiliation(s)
- A Switlicka
- Department of Crystallography, Institute of Chemistry, University of Silesia, 9th Szkolna St., 40-006 Katowice, Poland.
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18
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Wang L, Zlatar M, Vlahović F, Demeshko S, Philouze C, Molton F, Gennari M, Meyer F, Duboc C, Gruden M. Experimental and Theoretical Identification of the Origin of Magnetic Anisotropy in Intermediate Spin Iron(III) Complexes. Chemistry 2018; 24:5091-5094. [PMID: 29447424 PMCID: PMC5969241 DOI: 10.1002/chem.201705989] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Indexed: 11/24/2022]
Abstract
The complexes [FeLN2S2X] [in which LN2S2=2,2′‐(2,2′‐bipryridine‐6,6′‐diyl)bis(1,1′‐diphenylethanethiolate) and X=Cl, Br and I], characterized crystallographically earlier and here (Fe(L)Br), reveal a square pyramidal coordinated FeIII ion. Unusually, all three complexes have intermediate spin ground states. Susceptibility measurements, powder cw X‐ and Q‐band EPR spectra, and zero‐field powder Mössbauer spectra show that all complexes display distinct magnetic anisotropy, which has been rationalized by DFT calculations.
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Affiliation(s)
- Lianke Wang
- University of Grenoble Alpes, DCM, CNRS UMR 5250, Grenoble, France
| | - Matija Zlatar
- Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Serbia
| | - Filip Vlahović
- Faculty of Chemistry, University of Belgrade, Studentski trg 12-16, 11000, Belgrade, Serbia
| | - Serhiy Demeshko
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstr. 4, 37077, Göttingen, Germany
| | | | - Florian Molton
- University of Grenoble Alpes, DCM, CNRS UMR 5250, Grenoble, France
| | - Marcello Gennari
- University of Grenoble Alpes, DCM, CNRS UMR 5250, Grenoble, France
| | - Franc Meyer
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstr. 4, 37077, Göttingen, Germany
| | - Carole Duboc
- University of Grenoble Alpes, DCM, CNRS UMR 5250, Grenoble, France
| | - Maja Gruden
- Faculty of Chemistry, University of Belgrade, Studentski trg 12-16, 11000, Belgrade, Serbia
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19
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Khan S, Peters V, Kowalewski J, Odelius M. Zero-field splitting in the isoelectronic aqueous Gd(III) and Eu(II) complexes from a first principles analysis. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2018.02.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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20
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Pallares IG, Moore TC, Escalante-Semerena JC, Brunold TC. Spectroscopic Studies of the EutT Adenosyltransferase from Salmonella enterica: Evidence of a Tetrahedrally Coordinated Divalent Transition Metal Cofactor with Cysteine Ligation. Biochemistry 2017; 56:364-375. [PMID: 28045498 DOI: 10.1021/acs.biochem.6b00750] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The EutT enzyme from Salmonella enterica, a member of the family of ATP:cobalt(I) corrinoid adenosyltransferase (ACAT) enzymes, requires a divalent transition metal ion for catalysis, with Fe(II) yielding the highest activity. EutT contains a unique cysteine-rich HX11CCX2C(83) motif (where H and the last C occupy the 67th and 83rd positions, respectively, in the amino acid sequence) not found in other ACATs and employs an unprecedented mechanism for the formation of adenosylcobalamin. Recent kinetic and spectroscopic studies of this enzyme revealed that residues in the HX11CCX2C(83) motif are required for the tight binding of the divalent metal ion and are critical for the formation of a four-coordinate (4c) cob(II)alamin [Co(II)Cbl] intermediate in the catalytic cycle. However, it remained unknown which, if any, of the residues in the HX11CCX2C(83) motif bind the divalent metal ion. To address this issue, we have characterized Co(II)-substituted wild-type EutT (EutTWT/Co) by using electronic absorption, electron paramagnetic resonance, and magnetic circular dichroism (MCD) spectroscopies. Our results indicate that the reduced catalytic activity of EutTWT/Co relative to that of the Fe(II)-containing enzyme arises from the incomplete incorporation of Co(II) ions and, thus, a decrease in the relative population of 4c Co(II)Cbl. Our MCD data for EutTWT/Co also reveal that the Co(II) ions reside in a distorted tetrahedral coordination environment with direct cysteine sulfur ligation. Additional spectroscopic studies of EutT/Co variants possessing a single alanine substitution of either His67, His75, Cys79, Cys80, or Cys83 indicate that Cys80 coordinates to the Co(II) ion, while the additional residues are important for maintaining the structural integrity and/or high affinity of the metal binding site.
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Affiliation(s)
- Ivan G Pallares
- Department of Chemistry, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Theodore C Moore
- Department of Microbiology, University of Georgia , Athens, Georgia 30602, United States
| | | | - Thomas C Brunold
- Department of Chemistry, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
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21
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Iannuzzi TE, Gao Y, Baker TM, Deng L, Neidig ML. Magnetic circular dichroism and density functional theory studies of electronic structure and bonding in cobalt(ii)–N-heterocyclic carbene complexes. Dalton Trans 2017; 46:13290-13299. [DOI: 10.1039/c7dt01748k] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The combination of simple cobalt salts and N-heterocyclic carbene (NHC) ligands has been highly effective in C–H functionalization, hydroarylation and cross-coupling catalysis, though displaying a strong dependence on the identity of the NHC ligand.
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Affiliation(s)
| | - Yafei Gao
- State Key Laboratory of Organometallic Chemistry
- Shanghai Institute of Organic Chemistry
- University of Chinese Academy of Sciences
- Chinese Academy of Sciences
- Shanghai
| | - Tessa M. Baker
- Department of Chemistry
- University of Rochester
- Rochester
- USA
| | - Liang Deng
- State Key Laboratory of Organometallic Chemistry
- Shanghai Institute of Organic Chemistry
- University of Chinese Academy of Sciences
- Chinese Academy of Sciences
- Shanghai
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22
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Charron G, Malkin E, Rogez G, Batchelor LJ, Mazerat S, Guillot R, Guihéry N, Barra AL, Mallah T, Bolvin H. Unraveling σ and π Effects on Magnetic Anisotropy incis-NiA4B2Complexes: Magnetization, HF-HFEPR Studies, First-Principles Calculations, and Orbital Modeling. Chemistry 2016; 22:16850-16862. [DOI: 10.1002/chem.201602837] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Gaëlle Charron
- Institut de Chimie Moléculaire et des Matériaux d'Orsay; CNRS; Université de Paris-Sud 11; 91405 Orsay Cedex France
- Laboratoire MSC; Université Paris 7 Diderot; Paris France
| | - Elena Malkin
- Laboratoire de Chimie et Physique Quantiques; CNRS; Université Toulouse III; 118 route de Narbonne 31062 Toulouse France
- CTCC; Department of Chemistry; University of Tromsø; 9037 Tromsø Norway
| | - Guillaume Rogez
- Institut de Physique et Chimie des Matériaux de Strasbourg; Université de Strasbourg; 23 rue du Loess, BP 43 67034 Strasbourg Cedex 2 France
| | - Luke J. Batchelor
- Institut de Chimie Moléculaire et des Matériaux d'Orsay; CNRS; Université de Paris-Sud 11; 91405 Orsay Cedex France
| | - Sandra Mazerat
- Institut de Chimie Moléculaire et des Matériaux d'Orsay; CNRS; Université de Paris-Sud 11; 91405 Orsay Cedex France
| | - Régis Guillot
- Institut de Chimie Moléculaire et des Matériaux d'Orsay; CNRS; Université de Paris-Sud 11; 91405 Orsay Cedex France
| | - Nathalie Guihéry
- Laboratoire de Chimie et Physique Quantiques; CNRS; Université Toulouse III; 118 route de Narbonne 31062 Toulouse France
| | - Anne-Laure Barra
- Laboratoire National des Champs Magnétiques Intenses; CNRS; 25 rue des Martyrs, B.P. 166 38042 Grenoble Cedex 9 France
| | - Talal Mallah
- Institut de Chimie Moléculaire et des Matériaux d'Orsay; CNRS; Université de Paris-Sud 11; 91405 Orsay Cedex France
| | - Hélène Bolvin
- Laboratoire de Chimie et Physique Quantiques; CNRS; Université Toulouse III; 118 route de Narbonne 31062 Toulouse France
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23
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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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24
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Ziegenbalg S, Hornig D, Görls H, Plass W. Cobalt(II)-Based Single-Ion Magnets with Distorted Pseudotetrahedral [N2O2] Coordination: Experimental and Theoretical Investigations. Inorg Chem 2016; 55:4047-58. [DOI: 10.1021/acs.inorgchem.6b00373] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sven Ziegenbalg
- Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstrasse 8, 07743 Jena, Germany
| | - David Hornig
- Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstrasse 8, 07743 Jena, Germany
| | - Helmar Görls
- Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstrasse 8, 07743 Jena, Germany
| | - Winfried Plass
- Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstrasse 8, 07743 Jena, Germany
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25
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Piecha-Bisiorek A, Bieńko A, Jakubas R, Boča R, Weselski M, Kinzhybalo V, Pietraszko A, Wojciechowska M, Medycki W, Kruk D. Physical and Structural Characterization of Imidazolium-Based Organic–Inorganic Hybrid: (C3N2H5)2[CoCl4]. J Phys Chem A 2016; 120:2014-21. [DOI: 10.1021/acs.jpca.5b11924] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anna Piecha-Bisiorek
- Faculty
of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland
| | - Alina Bieńko
- Faculty
of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland
| | - Ryszard Jakubas
- Faculty
of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland
| | - Roman Boča
- Department
of Chemistry, FPV, University of SS Cyril and Methodius, Trnava, Slovakia
| | - Marek Weselski
- Faculty
of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland
| | - Vasyl Kinzhybalo
- Institute of Low Temperature and Structure Research, PAS, Okólna 2, 50-422 Wrocław, Poland
| | - Adam Pietraszko
- Institute of Low Temperature and Structure Research, PAS, Okólna 2, 50-422 Wrocław, Poland
| | - Martyna Wojciechowska
- Faculty
of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland
| | - Wojciech Medycki
- Institute of Molecular Physics, PAS, M. Smoluchowskiego 17, 60-179 Poznań, Poland
| | - Danuta Kruk
- Faculty of Mathematics and Computer Science, University of Warmia & Mazury, Słoneczna 54, 10-710 Olsztyn, Poland
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26
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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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27
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Krzystek J, Telser J. Measuring giant anisotropy in paramagnetic transition metal complexes with relevance to single-ion magnetism. Dalton Trans 2016; 45:16751-16763. [DOI: 10.1039/c6dt01754a] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
“Giant magnetic anisotropy” is a phenomenon identified in certain coordination complexes of nd- and nf-block ions. The strengths and weaknesses of multiple methods used to measure it are evaluated.
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Affiliation(s)
- J. Krzystek
- National High Magnetic Field Laboratory
- Florida State University
- Tallahassee
- USA
| | - Joshua Telser
- Department of Biological
- Chemical and Physical Sciences
- Roosevelt University
- Chicago
- USA
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28
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Brazzolotto D, Gennari M, Yu S, Pécaut J, Rouzières M, Clérac R, Orio M, Duboc C. An Experimental and Theoretical Investigation on Pentacoordinated Cobalt(III) Complexes with an Intermediate S=
1 Spin State: How Halide Ligands Affect their Magnetic Anisotropy. Chemistry 2015; 22:925-33. [DOI: 10.1002/chem.201502997] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Indexed: 11/06/2022]
Affiliation(s)
| | | | - Shengying Yu
- Univ. Grenoble Alpes, DCM, CNRS UMR 5250; 38000 Grenoble France
| | - Jacques Pécaut
- Univ. Grenoble Alpes, CEA, INAC-SCIB; 38000 Grenoble France
| | - Mathieu Rouzières
- CNRS, CRPP, UPR 8641; F-33600 Pessac France
- Univ. Bordeaux, CRPP, UPR 8641; F-33600 Pessac France
| | - Rodolphe Clérac
- CNRS, CRPP, UPR 8641; F-33600 Pessac France
- Univ. Bordeaux, CRPP, UPR 8641; F-33600 Pessac France
| | - Maylis Orio
- Aix Marseille Université, ISM2, CNRS UMR 7313; 13397 Marseille France
| | - Carole Duboc
- Univ. Grenoble Alpes, DCM, CNRS UMR 5250; 38000 Grenoble France
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29
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Zhang ZH, Wu SY, Li GL, Kuang MQ, Ding CC. Theoretical investigations of the spin Hamiltonian parameters for the CoCl(PPh 3) 3molecules. Mol Phys 2015. [DOI: 10.1080/00268976.2015.1029028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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30
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Use of magnetic circular dichroism to study dinuclear metallohydrolases and the corresponding biomimetics. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2015; 44:393-415. [DOI: 10.1007/s00249-015-1053-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Revised: 05/30/2015] [Accepted: 06/07/2015] [Indexed: 11/26/2022]
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31
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Saber MR, Dunbar KR. Ligands effects on the magnetic anisotropy of tetrahedral cobalt complexes. Chem Commun (Camb) 2015; 50:12266-9. [PMID: 25183324 DOI: 10.1039/c4cc05724d] [Citation(s) in RCA: 160] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The effect of ligands with heavy donor atoms on the magnetic anisotropy of the pseudo-tetrahedral cobalt complexes, Co(quinoline)2I2 (1) and Co(EPh3)2I2 (2-3) (E = P, As) has been investigated. The axial zero-field splitting parameter D was found to vary from +9.2 cm(-1) in 1 to -36.9 cm(-1) in 2 and -74.7 cm(-1) in 3. Compounds 2 and 3 exhibit slow relaxation of the magnetization up to 4 K under an applied dc field, indicating SMM behavior.
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Affiliation(s)
- Mohamed R Saber
- Department of Chemistry, Texas A&M University, College Station, TX 77842-3012, USA.
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32
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Chiu CC, Chen JH, Wang SS, Tung JY. Magnetic susceptibility and EPR spectra of Co(II) 2-N substituted N-confused porphyrin: Co(2-NCH2-p-C6H4-isoC3H7-21-CH2-p-C6H4CH3-NCTPP)Cl. Polyhedron 2014. [DOI: 10.1016/j.poly.2014.06.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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33
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Boča R, Miklovič J, Titiš J. Simple mononuclear cobalt(II) complex: a single-molecule magnet showing two slow relaxation processes. Inorg Chem 2014; 53:2367-9. [PMID: 24524226 DOI: 10.1021/ic5000638] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Complex [Co(PPh3)2Br2] possesses intermediate magnetic anisotropy, D/hc = -13 cm(-1). It displays superparamagnetic behavior either in the absence of the magnetic field or in fields of Bdc = 0.05, 0.1, 0.15, and 0.2 T. At Bdc = 0.1 T, the barrier to spin reversal U/kB = 37 K and the extrapolated relaxation time τ0 = 9.4 × 10(-11) s confirm its classification as a single-molecule magnet. At Bdc = 0.2 T, two relaxation processes are evidenced.
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Affiliation(s)
- Roman Boča
- Department of Chemistry, FPV, University of SS Cyril and Methodius , 91701 Trnava, Slovakia
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34
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Magnetism, IR and Raman spectra of a tetracoordinate and hexacoordinate Co(II) complexes derived from aminopyrimidine. Inorganica Chim Acta 2013. [DOI: 10.1016/j.ica.2013.09.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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35
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36
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Idešicová M, Titiš J, Krzystek J, Boča R. Zero-Field Splitting in Pseudotetrahedral Co(II) Complexes: a Magnetic, High-Frequency and -Field EPR, and Computational Study. Inorg Chem 2013; 52:9409-17. [DOI: 10.1021/ic400980b] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Monika Idešicová
- Department of Chemistry (FPV), University of SS. Cyril and Methodius, SK-917 01 Trnava,
Slovakia
| | - Ján Titiš
- Department of Chemistry (FPV), University of SS. Cyril and Methodius, SK-917 01 Trnava,
Slovakia
| | - J. Krzystek
- National High
Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Roman Boča
- Department of Chemistry (FPV), University of SS. Cyril and Methodius, SK-917 01 Trnava,
Slovakia
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37
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Chibotaru LF. Ab InitioMethodology for Pseudospin Hamiltonians of Anisotropic Magnetic Complexes. ADVANCES IN CHEMICAL PHYSICS 2013. [DOI: 10.1002/9781118571767.ch6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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38
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Jackson TA, Gutman CT, Maliekal J, Miller AF, Brunold TC. Geometric and electronic structures of manganese-substituted iron superoxide dismutase. Inorg Chem 2013; 52:3356-67. [PMID: 23461587 PMCID: PMC3974275 DOI: 10.1021/ic302867y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The active-site structures of the oxidized and reduced forms of manganese-substituted iron superoxide dismutase (Mn(Fe)SOD) are examined, for the first time, using a combination of spectroscopic and computational methods. On the basis of electronic absorption, circular dichroism (CD), magnetic CD (MCD), and variable-temperature variable-field MCD data obtained for oxidized Mn(Fe)SOD, we propose that the active site of this species is virtually identical to that of wild-type manganese SOD (MnSOD), with both containing a metal ion that resides in a trigonal bipyramidal ligand environment. This proposal is corroborated by quantum mechanical/molecular mechanical (QM/MM) computations performed on complete protein models of Mn(Fe)SOD in both its oxidized and reduced states and, for comparison, wild-type (WT) MnSOD. The major differences between the QM/MM optimized active sites of WT MnSOD and Mn(Fe)SOD are a smaller (His)N-Mn-N(His) equatorial angle and a longer (Gln146(69))NH···O(sol) H-bond distance in the metal-substituted protein. Importantly, these modest geometric differences are consistent with our spectroscopic data obtained for the oxidized proteins and high-field electron paramagnetic resonance spectra reported previously for reduced Mn(Fe)SOD and MnSOD. As Mn(Fe)SOD exhibits a reduction midpoint potential (E(m)) almost 700 mV higher than that of MnSOD, which has been shown to be sufficient for explaining the lack of SOD activity displayed by the metal-subtituted species (Vance, C. K.; Miller, A. F. Biochemistry 2001, 40, 13079-13087), E(m)'s were computed for our experimentally validated QM/MM optimized models of Mn(Fe)SOD and MnSOD. These computations properly reproduce the experimental trend and reveal that the drastically elevated E(m) of the metal substituted protein stems from a larger separation between the second-sphere Gln residue and the coordinated solvent in Mn(Fe)SOD relative to MnSOD, which causes a weakening of the corresponding H-bond interaction in the oxidized state and alleviates steric crowding in the reduced state.
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Affiliation(s)
| | | | - James Maliekal
- Department of Chemistry, University of Kentucky, Lexington, KY 40506
| | | | - Thomas C. Brunold
- To whom correspondence should be addressed: 1101 University Ave., Madison, WI 53706, phone: (608) 265-9056, fax: (608) 262-6143,
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39
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Kubica A, Kowalewski J, Kruk D, Odelius M. Zero-field splitting in nickel(II) complexes: A comparison of DFT and multi-configurational wavefunction calculations. J Chem Phys 2013; 138:064304. [DOI: 10.1063/1.4790167] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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40
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Zheng YZ, Qin L, Zheng Z, Xue W, Chen XM. Assembly of alternating spin-chains with magnetically anisotropic cobalt(II) dimers. Dalton Trans 2013; 42:1770-7. [PMID: 23165444 DOI: 10.1039/c2dt32362a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A dimeric carboxylato complex of cobalt(II), [Co(2)(II)(1,2-chedc)(2)(Im)(2)] (1) (1,2-chedc = cyclohex-1-ene-1,2-dicarboxylate and Im = imidazole), has been isolated. This complex can be further linked by chloro- or carboxylato-ligands, affording respectively one-dimensional chain structures of (1)(∞)[Co(2)(II)(μ-Cl)(2)(1,2-chedc)(Im)(2)] (2) and (1)(∞)[Co(II)(1,2-chedc)(Im)] (3). Compound 1 shows weak antiferromagnetic interactions passing through the body of the dicarboxylate as well as substantial single-ion magnetic anisotropy (zero-field splitting energy Δ = 8.5 cm(-1)). Both 2 and 3 exhibit typical alternating spin-chain behaviour in the higher-temperature region, but they display disparate behaviours at lower temperatures. For 2, alternating F-AF interactions compete (J(1) = 6.7 K and J(2) = -8.2 K), resulting in paramagnet-like behaviour with no clear evidence of three-dimensional contact. Compound 3 exhibits stronger intrachain AF-AF exchange-coupling interactions (J(1) = -9.3 K and J(2) = -4.3 K), leading to non-diamagnetic ground state due to the tiling of adjacent spins. Long-range magnetic ordering was observed below 10 K. Its narrow hysteresis loop suggests the use of 3 as a soft magnet.
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Affiliation(s)
- Yan-Zhen Zheng
- Centre for Applied Chemical Research, Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an 710054, China.
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41
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Maurice R, Graaf CD, Guihéry N. Theoretical determination of spin Hamiltonians with isotropic and anisotropic magnetic interactions in transition metal and lanthanide complexes. Phys Chem Chem Phys 2013; 15:18784-804. [DOI: 10.1039/c3cp52521j] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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42
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Liu B, Ding T, Hua WJ, Liu XM, Hu HM, Li SH, Zheng LM. Diruthenium(iii,iii) diphosphonate with a spin ground state S = 2. Dalton Trans 2013; 42:3429-33. [DOI: 10.1039/c2dt32306k] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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43
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Mathies G, Almeida RM, Gast P, Moura JJG, Groenen EJJ. Multifrequency EPR study of Fe3+ and Co2+ in the active site of desulforedoxin. J Phys Chem B 2012; 116:7122-8. [PMID: 22612627 DOI: 10.1021/jp3025655] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The understanding of the electronic structure of S > 1/2 transition-metal sites that show a large zero-field splitting (ZFS) of the magnetic sublevels benefits greatly from study by electron-paramagnetic-resonance (EPR) spectroscopy at frequencies above the standard 9.5 GHz. However, high-frequency EPR spectroscopy is technically challenging and still developing. Particularly the sensitivity of high-frequency EPR spectrometers is often too low to apply the technique in the study of transition-metal sites in proteins and enzymes. Here we report a multifrequency EPR study (at 9.5, 94.9, and 275.7 GHz) of the active site of the protein desulforedoxin, both in its natural Fe(3+) form and substituted with Co(2+). The 275.7 GHz EPR spectra made it possible to determine the ZFS parameters of the Fe(3+) site with high precision. No 275.7 GHz spectrum could be observed of the Co(2+) site, but based on 9.5 GHz spectra, its ZFS parameters could be estimated. We find that the typical variation in the geometry of the active site of a protein or enzyme, referred to as conformational strain, does not only make the detection of EPR spectra challenging, but also their analysis. Comparison of the EPR results on the active site of desulforedoxin to those of the closely related active site of rubredoxin illustrates the necessity of explicit quantum-chemical calculations in order to interrelate the electronic and geometric structure of biological transition-metal sites.
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Affiliation(s)
- Guinevere Mathies
- Department of Physics, Huygens Laboratory, Leiden University, The Netherlands
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44
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Tomkowicz Z, Ostrovsky S, Foro S, Calvo-Perez V, Haase W. Magnetooptical and Structural Investigations of Five Dimeric Cobalt(II) Complexes Mimicking Metalloenzyme Active Sites. Inorg Chem 2012; 51:6046-55. [DOI: 10.1021/ic202529p] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Z. Tomkowicz
- Eduard-Zintl-Institute
of Inorganic and Physical Chemistry, Darmstadt University of Technology, Petersenstrasse 20, 64287
Darmstadt, Germany
- Institute of Physics, Jagiellonian University, Reymonta 4,
30-059 Kraków, Poland
| | - S. Ostrovsky
- Eduard-Zintl-Institute
of Inorganic and Physical Chemistry, Darmstadt University of Technology, Petersenstrasse 20, 64287
Darmstadt, Germany
- Institute of Applied
Physics, Academy of Sciences of Moldova, Academy str. 5, MD-2028 Chisinau, Moldova
| | - S. Foro
- Clemens-Schoepf-Institute
of Organic Chemistry and Biochemistry, Darmstadt University of Technology, Petersenstrasse 23, 64287
Darmstadt, Germany
| | - V. Calvo-Perez
- Facultad Ciencias
Químicas y Farmacéuticas, Universidad de Chile, Casilla 233, Santiago, Chile
| | - W. Haase
- Eduard-Zintl-Institute
of Inorganic and Physical Chemistry, Darmstadt University of Technology, Petersenstrasse 20, 64287
Darmstadt, Germany
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45
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Krzystek J, Ozarowski A, Zvyagin SA, Telser J. High Spin Co(I): High-Frequency and -Field EPR Spectroscopy of CoX(PPh3)3 (X = Cl, Br). Inorg Chem 2012; 51:4954-64. [DOI: 10.1021/ic202185x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- J. Krzystek
- National High Magnetic Field
Laboratory (NHMFL), Florida State University, Tallahassee, Florida 32310, United States
| | - Andrew Ozarowski
- 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 (HZDR), 01314 Dresden, Germany
| | - Joshua Telser
- Department of Biological, Chemical
and Physical Sciences, Roosevelt University, Chicago, Illinois 60605, United States
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46
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Idešicová M, Dlháň Ľ, Moncoľ J, Titiš J, Boča R. Zero-field splitting in tetracoordinate Co(II) complexes. Polyhedron 2012. [DOI: 10.1016/j.poly.2012.01.023] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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47
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Geiger RA, Wijeratne GB, Day VW, Jackson TA. Steric and Electronic Influences on the Structures of Peroxomanganese(III) Complexes Supported by Tetradentate Ligands. Eur J Inorg Chem 2012. [DOI: 10.1002/ejic.201101391] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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48
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Bane K, Geiger RA, Chabolla SA, Jackson TA. Determination of zero-field splitting parameters for a MnIV center using variable-temperature, variable-field magnetic circular dichroism spectroscopy: Comparison to electron paramagnetic resonance spectroscopy. Inorganica Chim Acta 2012. [DOI: 10.1016/j.ica.2011.10.046] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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49
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Krzystek J, Smirnov D, Schlegel C, van Slageren J, Telser J, Ozarowski A. High-frequency and -field EPR and FDMRS study of the [Fe(H2O)6]2+ ion in ferrous fluorosilicate. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2011; 213:158-165. [PMID: 22015248 DOI: 10.1016/j.jmr.2011.09.046] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Revised: 08/24/2011] [Accepted: 09/23/2011] [Indexed: 05/31/2023]
Abstract
The complex [Fe(H2O)6]SiF6 is one of the most stable and best characterized high-spin Fe(II) salts and as such, is a paradigm for the study of this important transition metal ion. We describe high-frequency and -field electron paramagnetic resonance studies of both pure [Fe(H2O)6]SiF6 and [Zn(H2O)6]SiF6 doped with 8% of Fe(II). In addition, frequency domain magnetic resonance spectroscopy was applied to these samples. High signal-to-noise, high resolution spectra were recorded which allowed an accurate determination of spin Hamiltonian parameters for Fe(II) in each of these two, related, environments. For pure [Fe(H2O)6]SiF6, the following parameters were obtained: D=+11.95(1) cm(-1), E=0.658(4) cm(-1), g=[2.099(4),2.151(5),1.997(3)], along with fourth-order zero-field splitting parameters: B4(0)=17(1)×10(-4) cm(-1) and B4(4)=18(4)×10(-4) cm(-1), which are rarely obtainable by any technique. For the doped complex, D=+13.42(1) cm(-1), E=0.05(1) cm(-1), g=[2.25(1),2.22(1),2.23(1)]. These parameters are in good agreement with those obtained using other techniques. Ligand-field theory was used to analyze the electronic absorption data for [Fe(H2O)6]SiF6 and suggests that the ground state is 5A1, which allows successful use of a spin Hamiltonian model. Density functional theory and unrestricted Hartree-Fock calculations were performed which, in the case of latter, reproduced the spin Hamiltonian parameters very well for the doped complex.
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Affiliation(s)
- J Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
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50
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Wojciechowska A, Daszkiewicz M, Staszak Z, Trusz-Zdybek A, Bieńko A, Ozarowski A. Synthesis, Crystal Structure, Spectroscopic, Magnetic, Theoretical, and Microbiological Studies of a Nickel(II) Complex of l-Tyrosine and Imidazole, [Ni(Im)2(l-tyr)2]·4H2O. Inorg Chem 2011; 50:11532-42. [PMID: 22010795 DOI: 10.1021/ic201471f] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Marek Daszkiewicz
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wroclaw, Poland
| | | | | | - Alina Bieńko
- Faculty of Chemistry, University of Wroclaw, 14 F. Joliot-Curie, 50-383 Wroclaw, Poland
| | - Andrzej Ozarowski
- National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
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