1
|
Errulat D, Harriman KLM, Gálico DA, Salerno EV, van Tol J, Mansikkamäki A, Rouzières M, Hill S, Clérac R, Murugesu M. Slow magnetic relaxation in a europium(II) complex. Nat Commun 2024; 15:3010. [PMID: 38589348 PMCID: PMC11001981 DOI: 10.1038/s41467-024-46196-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 02/14/2024] [Indexed: 04/10/2024] Open
Abstract
Single-ion anisotropy is vital for the observation of Single-Molecule Magnet (SMM) properties (i.e., a slow dynamics of the magnetization) in lanthanide-based systems. In the case of europium, the occurrence of this phenomenon has been inhibited by the spin and orbital quantum numbers that give way to J = 0 in the trivalent state and the half-filled population of the 4f orbitals in the divalent state. Herein, by optimizing the local crystal field of a quasi-linear bis(silylamido) EuII complex, the [EuII(N{SiMePh2}2)2] SMM is described, providing an example of a europium complex exhibiting slow relaxation of its magnetization. This behavior is dominated by a thermally activated (Orbach-like) mechanism, with an effective energy barrier of approximately 8 K, determined by bulk magnetometry and electron paramagnetic resonance. Ab initio calculations confirm second-order spin-orbit coupling effects lead to non-negligible axial magnetic anisotropy, splitting the ground state multiplet into four Kramers doublets, thereby allowing for the observation of an Orbach-like relaxation at low temperatures.
Collapse
Affiliation(s)
- Dylan Errulat
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Katie L M Harriman
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Diogo A Gálico
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Elvin V Salerno
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32310, USA
| | - Johan van Tol
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32310, USA
| | | | | | - Stephen Hill
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32310, USA.
- Department of Physics, Florida State University, Tallahassee, FL, 32306, USA.
| | - Rodolphe Clérac
- Univ. Bordeaux, CNRS, CRPP, UMR 5031, F-33600, Pessac, France.
| | - Muralee Murugesu
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada.
| |
Collapse
|
2
|
Toubiana LA, Valaydon-Pillay A, Elinburg JK, Bacon JW, Ozarowski A, Doerrer LH, Stoian SA. Spectroscopic and Theoretical Investigation of High-Spin Square-Planar and Trigonal Fe(II) Complexes Supported by Fluorinated Alkoxides. Inorg Chem 2024; 63:2370-2387. [PMID: 38259134 DOI: 10.1021/acs.inorgchem.3c03236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The electronic structures and spectroscopic behavior of three high-spin FeII complexes of fluorinated alkoxides were studied: square-planar {K(DME)2}2[Fe(pinF)2] (S) and quasi square-planar {K(C222)}2[Fe(pinF)2] (S') and trigonal-planar {K(18C6)}[Fe(OC4F9)3] (T) where pinF = perfluoropinacolate and OC4F9 = tris-perfluoro-t-butoxide. The zero-field splitting (ZFS) and hyperfine structure parameters of the S = 2 ground states were determined using field-dependent 57Fe Mössbauer and high-field and -frequency electron paramagnetic resonance (HFEPR) spectroscopies. The spin Hamiltonian parameters were analyzed with crystal field theory and corroborated by density functional theory (DFT) and ab initio complete active space self-consistent field (CASSCF) calculations. Whereas the ZFS tensor of S has a small rhombicity, E/D = 0.082, and a positive D = 15.17 cm-1, T exhibits a negative D = -9.16 cm-1 and a large rhombicity, E/D = 0.246. Computational investigation of the structural factors suggests that the ground-state electronic configuration and geometry of T's Fe site are determined by the interaction of [Fe(OC4F9)3]- with {K(18C6)}+. In contrast, two distinct countercations of S/S' have a negligible influence on their [Fe(pinF)2]2- moieties. Instead, the distortions in S' are likely induced by the chelate ring conformation change from δλ, observed for S, to the δδ conformation, determined for S'.
Collapse
Affiliation(s)
- Léa A Toubiana
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Adam Valaydon-Pillay
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844, United States
| | - Jessica K Elinburg
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Jeffrey W Bacon
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Linda H Doerrer
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Sebastian A Stoian
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844, United States
| |
Collapse
|
3
|
Choroba K, Palion-Gazda J, Machura B, Bieńko A, Wojtala D, Bieńko D, Rajnák C, Boča R, Ozarowski A, Ozerov M. Large Magnetic Anisotropy in Mono- and Binuclear cobalt(II) Complexes: The Role of the Distortion of the Coordination Sphere in Validity of the Spin-Hamiltonian Formalism. Inorg Chem 2024; 63:1068-1082. [PMID: 38166196 DOI: 10.1021/acs.inorgchem.3c03405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
To get a better insight into understanding the factors affecting the enhancement of the magnetic anisotropy in single molecule (single ion) magnets, two cobalt(II) complexes based on a tridentate ligand 2,6-di(thiazol-2-yl)pyridine substituted at the 4-position with N-methyl-pyrrol-2-yl have been synthesized and studied by X-ray crystallography, AC and DC magnetic data, FIRMS and HFEPR spectra, and theoretical calculations. The change of the counteranion in starting Co(II) salts results in the formation of pentacoordinated mononuclear [Co(mpyr-dtpy)Cl2]·2MeCN (1) complex and binuclear [Co(mpyr-dtpy)2][Co(NCS)4] (2) compound. The observed marked distortion of trigonal bipyramid geometry in 1 and cationic octahedral and anionic tetrahedral units in 2 brings up a question about the validity of the spin-Hamiltonian formalism and the possibility of determining the value and sign of the zero-field splitting D parameter. Both complexes exhibit field-induced slow magnetic relaxation with two or three relaxation channels at BDC = 0.3 T. The high-frequency relaxation time in the reciprocal form τ(HF)-1 = CTn develops according to the Raman relaxation mechanism (for 2, n = 8.8) and the phonon-bottleneck-like mechanism (for 1, n = 2.3). The high-frequency relaxation time at T = 2.0 K and BDC = 0.30 T is τ(HF) = 96 and 47 μs for 1 and 2, respectively.
Collapse
Affiliation(s)
- Katarzyna Choroba
- Institute of Chemistry, Faculty of Science and Technology, University of Silesia, Szkolna St. 9, Katowice 40-006, Poland
| | - Joanna Palion-Gazda
- Institute of Chemistry, Faculty of Science and Technology, University of Silesia, Szkolna St. 9, Katowice 40-006, Poland
| | - Barbara Machura
- Institute of Chemistry, Faculty of Science and Technology, University of Silesia, Szkolna St. 9, Katowice 40-006, Poland
| | - Alina Bieńko
- Faculty of Chemistry, Joliot-Curie 14, Wroclaw 50-383, Poland
| | - Daria Wojtala
- Faculty of Chemistry, Joliot-Curie 14, Wroclaw 50-383, Poland
| | - Dariusz Bieńko
- Faculty of Chemistry, Wroclaw University of Science Technology, Wybrzeze Wyspiańskiego 27, Wroclaw 50-370, Poland
| | - Cyril Rajnák
- Faculty of Health Science and Faculty of Natural Sciences, University of SS Cyril and Methodius, Trnava SK-917 01, Slovakia
| | - Roman Boča
- Institute of Chemistry, Faculty of Science and Technology, University of Silesia, Szkolna St. 9, Katowice 40-006, Poland
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Mykhaylo Ozerov
- National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
| |
Collapse
|
4
|
Tin P, Jenkins MJ, Xing J, Caci N, Gai Z, Jin R, Wessel S, Krzystek J, Li C, Daemen LL, Cheng Y, Xue ZL. Haldane topological spin-1 chains in a planar metal-organic framework. Nat Commun 2023; 14:5454. [PMID: 37673921 PMCID: PMC10482874 DOI: 10.1038/s41467-023-41014-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 08/18/2023] [Indexed: 09/08/2023] Open
Abstract
Haldane topological materials contain unique antiferromagnetic chains with symmetry-protected energy gaps. Such materials have potential applications in spintronics and future quantum computers. Haldane topological solids typically consist of spin-1 chains embedded in extended three-dimensional (3D) crystal structures. Here, we demonstrate that [Ni(μ-4,4'-bipyridine)(μ-oxalate)]n (NiBO) instead adopts a two-dimensional (2D) metal-organic framework (MOF) structure of Ni2+ spin-1 chains weakly linked by 4,4'-bipyridine. NiBO exhibits Haldane topological properties with a gap between the singlet ground state and the triplet excited state. The latter is split by weak axial and rhombic anisotropies. Several experimental probes, including single-crystal X-ray diffraction, variable-temperature powder neutron diffraction (VT-PND), VT inelastic neutron scattering (VT-INS), DC susceptibility and specific heat measurements, high-field electron spin resonance, and unbiased quantum Monte Carlo simulations, provide a detailed, comprehensive characterization of NiBO. Vibrational (also known as phonon) properties of NiBO have been probed by INS and density-functional theory (DFT) calculations, indicating the absence of phonons near magnetic excitations in NiBO, suppressing spin-phonon coupling. The work here demonstrates that NiBO is indeed a rare 2D-MOF Haldane topological material.
Collapse
Affiliation(s)
- Pagnareach Tin
- Department of Chemistry, University of Tennessee, Knoxville, TN, 37996, USA
| | - Michael J Jenkins
- Department of Chemistry, University of Tennessee, Knoxville, TN, 37996, USA
| | - Jie Xing
- Center for Experimental Nanoscale Physics, Department of Physics and Astronomy, University of South Carolina, Columbia, SC, 29208, USA
| | - Nils Caci
- Institut für Theoretische Festkörperphysik, RWTH Aachen University, 52056, Aachen, Germany
| | - Zheng Gai
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Rongyin Jin
- Center for Experimental Nanoscale Physics, Department of Physics and Astronomy, University of South Carolina, Columbia, SC, 29208, USA
| | - Stefan Wessel
- Institut für Theoretische Festkörperphysik, RWTH Aachen University, 52056, Aachen, Germany
| | - J Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32310, USA
| | - Cheng Li
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Luke L Daemen
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Yongqiang Cheng
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Zi-Ling Xue
- Department of Chemistry, University of Tennessee, Knoxville, TN, 37996, USA.
| |
Collapse
|
5
|
Xiang L, Dhakal R, Ozerov M, Jiang Y, Mou BS, Ozarowski A, Huang Q, Zhou H, Fang J, Winter SM, Jiang Z, Smirnov D. Disorder-Enriched Magnetic Excitations in a Heisenberg-Kitaev Quantum Magnet Na_{2}Co_{2}TeO_{6}. PHYSICAL REVIEW LETTERS 2023; 131:076701. [PMID: 37656855 DOI: 10.1103/physrevlett.131.076701] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 07/31/2023] [Accepted: 08/03/2023] [Indexed: 09/03/2023]
Abstract
Using optical magnetospectroscopy, we investigate the magnetic excitations of Na_{2}Co_{2}TeO_{6} in a broad magnetic field range (0 T≤B≤17.5 T) at low temperature. Our measurements reveal rich spectra of in-plane magnetic excitations with a surprisingly large number of modes, even in the high-field spin-polarized state. Theoretical calculations find that the Na-occupation disorder in Na_{2}Co_{2}TeO_{6} plays a crucial role in generating these modes. Our Letter demonstrates the necessity to consider disorder in the spin environment in the search for Kitaev quantum spin liquid states in practicable materials.
Collapse
Affiliation(s)
- Li Xiang
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, USA
| | - Ramesh Dhakal
- Department of Physics and Center for Functional Materials, Wake Forest University, Winston-Salem, North Carolina 27109, USA
| | - Mykhaylo Ozerov
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, USA
| | - Yuxuan Jiang
- School of Physics and Optoelectronics, Anhui University, Hefei, Anhui 230601, China
- Center of Free Electron Laser and High Magnetic Field, Anhui University, Hefei 230601, China
| | - Banasree S Mou
- Department of Physics and Center for Functional Materials, Wake Forest University, Winston-Salem, North Carolina 27109, USA
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, USA
| | - Qing Huang
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Haidong Zhou
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Jiyuan Fang
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Stephen M Winter
- Department of Physics and Center for Functional Materials, Wake Forest University, Winston-Salem, North Carolina 27109, USA
| | - Zhigang Jiang
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Dmitry Smirnov
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, USA
| |
Collapse
|
6
|
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.
Collapse
|
7
|
Khatri G, Fritjofson G, Hanson-Flores J, Kwon J, Del Barco E. A 220 GHz-1.1 THz continuous frequency and polarization tunable quasi-optical electron paramagnetic resonance spectroscopic system. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2023; 94:034714. [PMID: 37012778 DOI: 10.1063/5.0107237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Accepted: 03/09/2023] [Indexed: 06/19/2023]
Abstract
Here, we describe a custom-designed quasi-optical system continuously operating in the frequency range 220 GHz to 1.1 THz with a temperature range of 5-300 K and magnetic fields up to 9 T capable of polarization rotation in both transmitter and receiver arms at any given frequency within the range through a unique double Martin-Puplett interferometry approach. The system employs focusing lenses to amplify the microwave power at the sample position and recollimate the beam to the transmission branch. The cryostat and split coil magnets are furnished with five optical access ports from all three major directions to the sample sitting on a two-axes rotatable sample holder capable of performing arbitrary rotations with respect to the field direction, enabling broad accessibility to experimental geometries. Initial results from test measurements on antiferromagnetic MnF2 single crystals are included to verify the operation of the system.
Collapse
Affiliation(s)
- Gyan Khatri
- Department of Physics, University of Central Florida, Orlando, Florida 32816, USA
| | - Gregory Fritjofson
- Department of Physics, University of Central Florida, Orlando, Florida 32816, USA
| | - Jacob Hanson-Flores
- Department of Physics, University of Central Florida, Orlando, Florida 32816, USA
| | - Jaesuk Kwon
- Department of Physics, University of Central Florida, Orlando, Florida 32816, USA
| | - Enrique Del Barco
- Department of Physics, University of Central Florida, Orlando, Florida 32816, USA
| |
Collapse
|
8
|
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: 0] [Impact Index Per Article: 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.
Collapse
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.
| |
Collapse
|
9
|
de Souza MS, Reis SG, Stinghen D, Escobar LBL, Allão Cassaro RA, Poneti G, S Bortolot C, Marbey J, Hill S, Vaz MGF. High-Frequency EPR Studies of New 2p-3d Complexes Based on a Triazolyl-Substituted Nitronyl Nitroxide Radical: The Role of Exchange Anisotropy in a Cu-Radical System. Inorg Chem 2022; 61:12118-12128. [PMID: 35876616 DOI: 10.1021/acs.inorgchem.2c00679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Using the 1-(m-tolyl)-1H-1,2,3-triazole-4-(4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) (TlTrzNIT) radical and metal β-diketonate complexes [M(hfac)2(H2O)2], where hfac is hexafluoroacetylacetonato, three new 2p-3d heterospin complexes were synthesized. Their structures were solved using single crystal X-ray diffraction data, and magnetic investigation was performed by DC and AC measurements and multifrequency EPR spectroscopy. Compounds 1 and 2 are isostructural complexes with molecular formula [M3(TlTrzNIT)2(hfac)6] (MII = Mn or Cu) while compound 3 is the mononuclear [Co(TlTrzNIT)(hfac)2] complex. In all complexes, the radical acts as a bidentate ligand through the oxygen atom of the nitroxide moiety and the nitrogen atom from the triazole group. Furthermore, in compounds 1 and 2, the TlTrzNIT is bridge-coordinated between two metal centers, leading to the formation of trinuclear complexes. The fitting of the static magnetic behavior reveals antiferromagnetic and ferromagnetic intramolecular interactions for complexes 1 and 2, respectively. The EPR spectra of 1 are well described by an isolated ferrimagnetic S = 13/2 (= 5/2 - 1/2 + 5/2 - 1/2 + 5/2) ground state with a biaxial zero-field splitting (ZFS) interaction characterized, respectively, by 2nd order axial and rhombic parameters, D and E, such that E/D is close to the maximum of 0.33. Meanwhile, EPR spectra for 2 are explained in terms of a ferromagnetic model with weakly anisotropic Cu-radical exchange interactions, giving rise to an isolated S = 5/2 (= 5 × 1/2) ground state with both an anisotropic g tensor and a weak ZFS interaction. Complex 2 represents one of only a few examples of Cu-radical moieties with measurable exchange anisotropy.
Collapse
Affiliation(s)
- Mateus S de Souza
- Instituto de Química, Universidade Federal Fluminense, Niterói, Rio de Janeiro 24020-150, Brazil
| | - Samira G Reis
- Instituto de Química, Universidade Federal Fluminense, Niterói, Rio de Janeiro 24020-150, Brazil
| | - Danilo Stinghen
- Instituto de Química, Universidade Federal Fluminense, Niterói, Rio de Janeiro 24020-150, Brazil
| | - Lívia B L Escobar
- Instituto de Física, Universidade Federal Fluminense, Niterói, Rio de Janeiro 24210-346, Brazil.,NHMFL, Florida State University, Tallahassee, Florida 32310, United States.,Departamento de Química, Pontifícia Universidade Católica, Gávea, Rio de Janeiro, RJ 22453-900, Brazil
| | - Rafael A Allão Cassaro
- Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro 21941-909, Brazil
| | - Giordano Poneti
- Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro 21941-909, Brazil
| | - Carolina S Bortolot
- Instituto de Química, Universidade Federal Fluminense, Niterói, Rio de Janeiro 24020-150, Brazil
| | - Jonathan Marbey
- NHMFL, Florida State University, Tallahassee, Florida 32310, United States.,Department of Physics, Florida State University, Tallahassee, Florida 32306, United States
| | - Stephen Hill
- NHMFL, Florida State University, Tallahassee, Florida 32310, United States.,Department of Physics, Florida State University, Tallahassee, Florida 32306, United States
| | - Maria G F Vaz
- Instituto de Química, Universidade Federal Fluminense, Niterói, Rio de Janeiro 24020-150, Brazil
| |
Collapse
|
10
|
Hansen HB, Krzystek J, Telser J, Swain A, Rajaraman G, Wadepohl H, Enders M. Solid-State Conformational Isomerism Lacking a Gas-Phase Energy Barrier: Its Structural, Spectroscopic, and Theoretical Identification in an Organochromium(III) Complex. Organometallics 2022. [DOI: 10.1021/acs.organomet.2c00182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Helge-Boj Hansen
- Institute of Inorganic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
| | - J. Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Joshua Telser
- Department of Biological, Physical, and Health Sciences, Roosevelt University, Chicago, Illinois 60605, United States
| | - Abinash Swain
- Institute of Inorganic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Hubert Wadepohl
- 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
| |
Collapse
|
11
|
Gamage EH, Ribeiro RA, Harmer CP, Canfield PC, Ozarowski A, Kovnir K. Tuning of Cr-Cr Magnetic Exchange through Chalcogenide Linkers in Cr 2 Molecular Dimers. Inorg Chem 2022; 61:6160-6174. [PMID: 35412816 DOI: 10.1021/acs.inorgchem.2c00298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A set of three Cr-dimer compounds, Cr2Q2(en)4X2 (Q: S, Se; X: Br, Cl; en: ethylenediamine), with monoatomic chalcogenide bridges have been synthesized via a single-step solvothermal route. Chalcogenide linkers mediate magnetic exchange between Cr3+ centers, while bidentate ethylenediamine ligands complete the distorted octahedral coordination of Cr centers. Unlike the compounds previously reported, none of the chalcogenide atoms are connected to extra ligands. Magnetic susceptibility studies indicate antiferromagnetic coupling between Cr3+ centers, which are moderate in Cr2Se2(en)4X2 and stronger in Cr2S2(en)4Cl2. Fitting the magnetic data requires a biquadratic exchange term. High-frequency EPR spectra showing characteristic signals due to coupled S = 1 spin states could be interpreted in terms of the "giant spin" Hamiltonian. A fourth compound, Cr2Se8(en)4, has a single diatomic Se bridge connecting the two Cr3+ centers and shows weak ferromagnetic exchange interactions. This work demonstrates the tunability in strength and type of exchange interactions between metal centers by manipulating the interatomic distances and number of bridging chalcogenide linkers.
Collapse
Affiliation(s)
- Eranga H Gamage
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States.,Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
| | - Raquel A Ribeiro
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States.,Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, United States
| | - Colin P Harmer
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States.,Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
| | - Paul C Canfield
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States.,Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, United States
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, 1800 E Paul Dirac Dr, Tallahassee, Florida 32310, United States
| | - Kirill Kovnir
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States.,Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
| |
Collapse
|
12
|
Kühne IA, Ozarowski A, Sultan A, Esien K, Carter AB, Wix P, Casey A, Heerah-Booluck M, Keene TD, Müller-Bunz H, Felton S, Hill S, Morgan GG. Homochiral Mn 3+ Spin-Crossover Complexes: A Structural and Spectroscopic Study. Inorg Chem 2022; 61:3458-3471. [PMID: 35175771 PMCID: PMC8889584 DOI: 10.1021/acs.inorgchem.1c03379] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Structural, magnetic,
and spectroscopic data on a Mn3+ spin-crossover complex
with Schiff base ligand 4-OMe-Sal2323, isolated in crystal
lattices with five different counteranions,
are reported. Complexes of [Mn(4-OMe-Sal2323)]X where X
= ClO4– (1), BF4– (2), NO3– (3), Br– (4), and I– (5) crystallize isotypically in the chiral
orthorhombic space group P21212 with a range of spin state preferences for the [Mn(4-OMe-Sal2323)]+ complex cation over the temperature range
5–300 K. Complexes 1 and 2 are high-spin,
complex 4 undergoes a gradual and complete thermal spin
crossover, while complexes 3 and 5 show
stepped crossovers with different ratios of spin triplet and quintet
forms in the intermediate temperature range. High-field electron paramagnetic
resonance was used to measure the zero-field splitting parameters
associated with the spin triplet and quintet states at temperatures
below 10 K for complexes 4 and 2 with respective
values: DS=1 = +23.38(1) cm–1, ES=1 = +2.79(1) cm–1,
and DS=2 =
+6.9(3) cm–1, with a distribution of E parameters for the S = 2 state. Solid-state circular
dichroism (CD) spectra on high-spin complex 1 at room
temperature reveal a 2:1 ratio of enantiomers in the chiral conglomerate,
and solution CD measurements on the same sample in methanol show that
it is stable toward racemization. Solid-state UV–vis absorption
spectra on high-spin complex 1 and mixed S = 1/S = 2 sample 5 reveal different
intensities at higher energies, in line with the different electronic
composition. The statistical prevalence of homochiral crystallization
of [Mn(4-OMe-Sal2323)]+ in five lattices with
different achiral counterions suggests that the chirality may be directed
by the 4-OMe-Sal2323 ligand. Zero-field
splitting parameters of the spin triplet and
quintet forms of a spin-crossover Mn3+ complex stabilized
in lattices with different counterions are measured by high-field
electron paramagnetic resonance at different frequencies. The homochiral
crystallization of the enantiopure Δ or Λ forms of the
chelate complex, despite the use of achiral anions, is attributed
to the steric influence of the ligand substituent.
Collapse
Affiliation(s)
- Irina A Kühne
- School of Chemistry, University College Dublin (UCD), Belfield, Dublin 4, Ireland.,FZU - Institute of Physics - Czech Academy of Sciences, Na Slovance 1999/2, Prague 8 182 21, Czech Republic
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Aizuddin Sultan
- School of Chemistry, University College Dublin (UCD), Belfield, Dublin 4, Ireland
| | - Kane Esien
- School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN, United Kingdom
| | - Anthony B Carter
- School of Chemistry, University College Dublin (UCD), Belfield, Dublin 4, Ireland
| | - Paul Wix
- School of Chemistry & CRANN Institute & AMBER Centre, Trinity College Dublin, University of Dublin, College Green, Dublin 2, Ireland
| | - Aoife Casey
- School of Chemistry, University College Dublin (UCD), Belfield, Dublin 4, Ireland
| | | | - Tony D Keene
- School of Chemistry, University College Dublin (UCD), Belfield, Dublin 4, Ireland
| | - Helge Müller-Bunz
- School of Chemistry, University College Dublin (UCD), Belfield, Dublin 4, Ireland
| | - Solveig Felton
- School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN, United Kingdom
| | - Stephen Hill
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States.,Department of Physics, Florida State University, Tallahassee, Florida 32306, United States
| | - Grace G Morgan
- School of Chemistry, University College Dublin (UCD), Belfield, Dublin 4, Ireland
| |
Collapse
|
13
|
Abstract
Baird's rule predicts that molecules with 4n π electrons should be aromatic in the triplet state, but the realization of simple ring systems with such an electronic ground state has been stymied by these molecules' tendency to distort into structures bearing a large singlet-triplet gap. Here, we show that the elusive benzene diradical dianion can be stabilized through creation of a binucleating ligand that enforces a tightly constrained inverse sandwich structure and direct magnetic exchange coupling. Specifically, we report the compounds [K(18-crown-6)(THF)2]2[M2(BzN6-Mes)] (M = Y, Gd; BzN6-Mes = 1,3,5-tris[2',6'-(N-mesityl)dimethanamino-4'-tert-butylphenyl]benzene), which feature a trigonal ligand that binds one trivalent metal ion on each face of a central benzene dianion. Antiferromagnetic exchange in the Gd3+ compound preferentially stabilizes the triplet state such that it becomes the molecular ground state. Single-crystal X-ray diffraction data and nucleus-independent chemical shift calculations support aromaticity, in agreement with Baird's rule.
Collapse
|
14
|
Stoian SA, Moshari M, Ferentinos E, Grigoropoulos A, Krzystek J, Telser J, Kyritsis P. Electronic Structure of Tetrahedral, S = 2, [Fe{(EP iPr 2) 2N} 2], E = S, Se, Complexes: Investigation by High-Frequency and -Field Electron Paramagnetic Resonance, 57Fe Mössbauer Spectroscopy, and Quantum Chemical Studies. Inorg Chem 2021; 60:10990-11005. [PMID: 34288665 DOI: 10.1021/acs.inorgchem.1c00670] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this work, we assessed the electronic structures of two pseudotetrahedral complexes of FeII, [Fe{(SPiPr2)2N}2] (1) and [Fe{(SePiPr2)2N}2] (2), using high-frequency and -field EPR (HFEPR) and field-dependent 57Fe Mössbauer spectroscopies. This investigation revealed S = 2 ground states characterized by moderate, negative zero-field splitting (zfs) parameters D. The crystal-field (CF) theory analysis of the spin Hamiltonian (sH) and hyperfine structure parameters revealed that the orbital ground states of 1 and 2 have a predominant dx2-y2 character, which is admixed with dz2 (∼10%). Although replacing the S-containing ligands of 1 by their Se-containing analogues in 2 leads to a smaller |D| value, our theoretical analysis, which relied on extensive ab initio CASSCF calculations, suggests that the ligand spin-orbit coupling (SOC) plays a marginal role in determining the magnetic anisotropy of these compounds. Instead, the dx2-y2β → dxyβ excitations yield a large negative contribution, which dominates the zfs of both 1 and 2, while the different energies of the dx2-y2β → dxzβ transitions are the predominant factor responsible for the difference in zfs between 1 and 2. The electronic structures of these compounds are contrasted with those of other [FeS4] sites, including reduced rubredoxin by considering a D2-type distortion of the [Fe(E-X)4] cores, where E = S, Se; X = C, P. Our combined CASSCF/DFT calculations indicate that while the character of the orbital ground state and the quintet excited states' contribution to the zfs of 1 and 2 are modulated by the magnitude of the D2 distortion, this structural change does not impact the contribution of the excited triplet states.
Collapse
Affiliation(s)
- Sebastian A Stoian
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844, United States
| | - Mahsa Moshari
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844, United States
| | - Eleftherios Ferentinos
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Zografou, 15771 Athens, Greece
| | - Alexios Grigoropoulos
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Zografou, 15771 Athens, Greece
| | - J Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Joshua Telser
- Department of Biological, Physical, and Health Sciences, Roosevelt University, Chicago, Illinois 60605, United States
| | - Panayotis Kyritsis
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Zografou, 15771 Athens, Greece
| |
Collapse
|
15
|
Gompa TP, Greer SM, Rice NT, Jiang N, Telser J, Ozarowski A, Stein BW, La Pierre HS. High-Frequency and -Field Electron Paramagnetic Resonance Spectroscopic Analysis of Metal-Ligand Covalency in a 4f 7 Valence Series (Eu 2+, Gd 3+, and Tb 4+). Inorg Chem 2021; 60:9064-9073. [PMID: 34106710 DOI: 10.1021/acs.inorgchem.1c01062] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The recent isolation of molecular tetravalent lanthanide complexes has enabled renewed exploration of the effect of oxidation state on the single-ion properties of the lanthanide ions. Despite the isotropic nature of the 8S ground state in a tetravalent terbium complex, [Tb(NP(1,2-bis-tBu-diamidoethane)(NEt2))4], preliminary X-band electron paramagnetic resonance (EPR) measurements on tetravalent terbium complexes show rich spectra with broad resonances. The complexity of these spectra highlights the limits of conventional X-band EPR for even qualitative determination of zero-field splitting (ZFS) in these complexes. Therefore, we report the synthesis and characterization of a novel valence series of 4f7 molecular complexes spanning three oxidation states (Eu2+, Gd3+, and Tb4+) featuring a weak-field imidophosphorane ligand system, and employ high-frequency and -field electron paramagnetic resonance (HFEPR) to obtain quantitative values for ZFS across this valence series. The series was designed to minimize deviation in the first coordination sphere from the pseudotetrahedral geometry in order to directly interrogate the role of metal identity and charge on the complexes' electronic structures. These HFEPR studies are supported by crystallographic analysis and quantum-chemical calculations to assess the relative covalent interactions in each member of this valence series and the effect of the oxidation state on the splitting of the ground state and first excited state.
Collapse
Affiliation(s)
| | - Samuel M Greer
- Los Alamos National Laboratory (LANL), Los Alamos, New Mexico 87545, United States
| | | | | | - Joshua Telser
- Department of Biological, Physical and Health Sciences, Roosevelt University, Chicago, Illinois 60605, United States
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory (NHMFL), Florida State University, Tallahassee, Florida 32310, United States
| | - Benjamin W Stein
- Los Alamos National Laboratory (LANL), Los Alamos, New Mexico 87545, United States
| | | |
Collapse
|
16
|
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: 9] [Impact Index Per Article: 3.0] [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.
Collapse
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
| |
Collapse
|
17
|
Ghosh T, Marbey J, Wernsdorfer W, Hill S, Abboud KA, Christou G. Exchange-biased quantum tunnelling of magnetization in a [Mn 3] 2 dimer of single-molecule magnets with rare ferromagnetic inter-Mn 3 coupling. Phys Chem Chem Phys 2021; 23:8854-8867. [PMID: 33876045 DOI: 10.1039/d0cp06611g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A covalently-linked dimer of two single-molecule magnets (SMMs), [Mn6O(O2CMe)6(1,3-ppmd)3](ClO4)2, has been synthesized from the reaction of [Mn3O(O2CMe)6(py)3](ClO4) with 1,3-phenylene-bis(pyridin-2-ylmethanone) dioxime (1,3-ppmdH2). It contains two [MnIII3O]+7 triangular units linked by three 1,3-ppmd2- groups into an [Mn3]2 dimer with D3 symmetry. Solid-state dc and ac magnetic susceptibility measurements showed that each Mn3 subunit retains its properties as an SMM with an S = 6 ground state. Magnetization vs. dc field sweeps on a single crystal reveal hysteresis loops below 1.3 K exhibiting exchange-biased quantum tunnelling of magnetization (QTM) steps with a bias field of +0.06 T. This is the first example of a dimer of SMMs showing a positive exchange bias of the QTM steps in the hysteresis loops, and it has therefore been subjected to a detailed analysis. Simulation of the loops determines that each Mn3 unit is exchange-coupled with its neighbour primarily through the 1,3-ppmd2- linkers, confirming a weak ferromagnetic inter-Mn3 interaction of J12≈ +6.5 mK (Ĥ = -2Jŝi·ŝj convention). High-frequency EPR studies of a microcrystalline powder sample enable accurate determination of the zero-field splitting parameters of the uncoupled Mn3 SMMs, while also confirming the weak exchange interaction between the two SMMs within each [Mn3]2 dimer. The combined results emphasize the ability of designed covalent linkers to generate inter-SMM coupling of a particular sign and relative magnitude, and thus the ability of such linkers to modulate the quantum physics. As such, this work supports the feasibility of using designed covalent linkers to develop molecular oligomers of SMMs, or other magnetic molecules, as multi-qubit systems and/or other components of new quantum technologies.
Collapse
Affiliation(s)
- Tuhin Ghosh
- Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, USA.
| | | | | | | | | | | |
Collapse
|
18
|
Nehrkorn J, Greer SM, Malbrecht BJ, Anderton KJ, Aliabadi A, Krzystek J, Schnegg A, Holldack K, Herrmann C, Betley TA, Stoll S, Hill S. Spectroscopic Investigation of a Metal-Metal-Bonded Fe 6 Single-Molecule Magnet with an Isolated S = 19/ 2 Giant-Spin Ground State. Inorg Chem 2021; 60:4610-4622. [PMID: 33683105 DOI: 10.1021/acs.inorgchem.0c03595] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The metal-metal-bonded molecule [Bu4N][(HL)2Fe6(dmf)2] (Fe6) was previously shown to possess a thermally isolated spin S = 19/2 ground state and found to exhibit slow magnetization relaxation below a blocking temperature of ∼5 K [J. Am. Chem. Soc. 2015, 137, 13949-13956]. Here, we present a comprehensive spectroscopic investigation of this unique single-molecule magnet (SMM), combining ultrawideband field-swept high-field electron paramagnetic resonance (EPR) with frequency-domain Fourier-transform terahertz EPR to accurately quantify the spin Hamiltonian parameters of Fe6. Of particular importance is the near absence of a 4th-order axial zero-field splitting term, which is known to arise because of quantum mechanical mixing of spin states on account of the relatively weak spin-spin (superexchange) interactions in traditional polynuclear SMMs such as the celebrated Mn12-acetate. The combined high-resolution measurements on both powder samples and an oriented single crystal provide a quantitative measure of the isolated nature of the spin ground state in the Fe6 molecule, as well as additional microscopic insights into factors that govern the quantum tunneling of its magnetization. This work suggests strategies for improving the performance of polynuclear SMMs featuring direct metal-metal bonds and strong ferromagnetic spin-spin (exchange) interactions.
Collapse
Affiliation(s)
- Joscha Nehrkorn
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States.,Department of Chemistry, Institute for Inorganic and Applied Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany.,Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195, United States.,Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Samuel M Greer
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States.,Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Brian J Malbrecht
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Kevin J Anderton
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Azar Aliabadi
- Berlin Joint EPR Laboratory, Institut für Nanospektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Kekuléstraße 5, Berlin 12489, Germany
| | - J Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Alexander Schnegg
- Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany.,Berlin Joint EPR Laboratory, Institut für Nanospektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Kekuléstraße 5, Berlin 12489, Germany
| | - Karsten Holldack
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialen und Energie, Albert-Einstein-Straße 15, Berlin 12489, Germany
| | - Carmen Herrmann
- Department of Chemistry, Institute for Inorganic and Applied Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany
| | - Theodore A Betley
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Stefan Stoll
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195, United States
| | - Stephen Hill
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States.,Department of Physics, Florida State University, Tallahassee 32306, Florida, United States
| |
Collapse
|
19
|
Vassilyeva OY, Buvaylo EA, Kokozay VN, Skelton BW, Sobolev AN, Bieńko A, Ozarowski A. Ferro- vs. antiferromagnetic exchange between two Ni(II) ions in a series of Schiff base heterometallic complexes: what makes the difference? Dalton Trans 2021; 50:2841-2853. [PMID: 33533773 DOI: 10.1039/d0dt03957h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Three new NiII/ZnII heterometallics, [NiZnL'2(OMe)Cl]2 (1), [NiZnL''(Dea)Cl]2·2DMF (2) and [Ni2(H3L''')2(o-Van)(MeOH)2]Cl·[ZnCl2(H4L''')(MeOH)]·2MeOH (3), containing three-dentate Schiff bases as well as methanol or diethanolamine (H2Dea) or o-vanillin (o-VanH), all deprotonated, as bridging ligands were synthesized and structurally characterized. The Schiff base ligands were produced in situ from o-VanH and CH3NH2 (HL'), or NH2OH (HL"), or 2-amino-2-hydroxymethyl-propane-1,3-diol (H4L'''); a zerovalent metal (Ni and Zn in 1, Zn only in 2 and 3) was employed as a source of metal ions. The first two complexes are dimers with a Ni2Zn2O6 central core, while the third compound is a novel heterometallic cocrystal salt solvate built of a neutral zwitterionic ZnII Schiff base complex and of ionic salt containing dinuclear NiII complex cations. The crystal structures contain either centrosymmetric (1 and 2) or non-symmetric di-nickel fragment (3) with NiNi distances in the range 3.146-3.33 Å. The exchange coupling is antiferromagnetic for 1, J = 7.7 cm-1, and ferromagnetic for 2, J = -6.5 cm-1 (using the exchange Hamiltonian in a form Ĥ = Jŝ1ŝ2). The exchange interactions in 1 and 2 are comparable to the zero-field splitting (ZFS). High-field EPR revealed moderate magnetic anisotropy of opposite signs: D = 2.27 cm-1, E = 0.243 cm-1 (1) and D = -4.491 cm-1, E = -0.684 cm-1 (2). Compound 3 stands alone with very weak ferromagnetism (J = -0.6 cm-1) and much stronger magnetic anisotropy with D = -11.398 cm-1 and E = -1.151 cm-1. Attempts to calculate theoretically the exchange coupling (using the DFT "broken symmetry" method) and ZFS parameters (with the ab initio CASSCF method) were successful in predicting the trends of J and D among the three complexes, while the quantitative results were less good for 1 and 3.
Collapse
Affiliation(s)
- Olga Yu Vassilyeva
- Department of Chemistry, Taras Shevchenko National University of Kyiv, 64/13 Volodymyrska str., Kyiv 01601, Ukraine.
| | - Elena A Buvaylo
- Department of Chemistry, Taras Shevchenko National University of Kyiv, 64/13 Volodymyrska str., Kyiv 01601, Ukraine.
| | - Vladimir N Kokozay
- Department of Chemistry, Taras Shevchenko National University of Kyiv, 64/13 Volodymyrska str., Kyiv 01601, Ukraine.
| | - Brian W Skelton
- School of Molecular Sciences, M310, University of Western Australia, Perth, WA 6009, Australia
| | - Alexandre N Sobolev
- School of Molecular Sciences, M310, University of Western Australia, Perth, WA 6009, Australia
| | - Alina Bieńko
- Faculty of Chemistry, University of Wroclaw, F. Joliot-Curie 14, Wroclaw 50-383, Poland
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, USA
| |
Collapse
|
20
|
Soler M, Mahalay P, Wernsdorfer W, Lubert-Perquel D, Huffman JC, Abboud KA, Hill S, Christou G. Extending the family of reduced [Mn12O12(O2CR)16(H2O)x]n− complexes, and their sensitivity to environmental factors. Polyhedron 2021. [DOI: 10.1016/j.poly.2020.114968] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
21
|
Janas Z, Jezierska J, Ozarowski A, Bieńko A, Lis T, Jezierski A, Krawczyk M. Investigation of vanadium(III) and vanadium(IV) compounds supported by the linear diaminebis(phenolate) ligands: correlation between structures and magnetic properties. Dalton Trans 2021; 50:5184-5196. [PMID: 33881036 DOI: 10.1039/d0dt04302h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A family of oxidovanadium(iv) compounds containing linear diaminebis(phenolate (salans) L1-5 ligands (L1 = [MeNCH2CH2NMe(CH2-4-CMe2CH2CMe3-C6H3O)2]2-; L2 = [MeNCH2CH2NMe(CH2-4-CH3-C6H3O)2]2-; L3 = [MeNCH2CH2NMe(CH2-4-Cl-C6H3O)2]2-; L4 = {MeNCH2CH2NMe[CH2-4,6-(CH3)2-C6H2O]2}2-; and L5 = {MeNCH2CH2NMe[CH2-4,6-(Br)2-C6H2O]2}2-) and non-oxidovanadium(iii) with L2,4 and acac ligands has been prepared and characterized by chemical and physical techniques. Reactions of [VO(acac)2] with ligand precursors H2L2,4 in toluene or hexane afforded vanadium(iii) compounds [V(L-κ4ONNO)(acac)] (1, L2; 2, L4), while the use of acetonitrile or ethanol led to the formation of dimeric oxidovanadium(iv) [(VO)2(μ-L-κ4ONNO)2] (3, L1; 4, L2; 5, L3) and monomeric [VO(L-κ4ONNO)] (6, L4, 7, L5) compounds. As shown by X-ray crystallography, compounds 1 and 2 are monomeric, in which the chelating ligands afford octahedral cis-α geometry at the vanadium center. In the dimeric structures of 3-5, the six-coordinate vanadium centers are bridged via two oxygen atoms of the L1-3 ligands while the L4,5 ligands generate square pyramidal structures of the monomeric 6 and 7 compounds. HFEPR studies allowed the determination of the spin Hamiltonian parameters of the S = 1 spin state of the monomeric V(iii) and dimeric V(iv), and S = ½ in monomeric V(iv) compounds. Magnetic measurements of 3-5 indicated weak ferromagnetic metal-metal exchange interactions. A reaction course for the deoxygenation and reduction of vanadyl-salan compounds is proposed.
Collapse
Affiliation(s)
- Zofia Janas
- Faculty of Chemistry, University of Wrocław, 14, F. Joliot-Curie, 50-383 Wrocław, Poland.
| | - Julia Jezierska
- Faculty of Chemistry, University of Wrocław, 14, F. Joliot-Curie, 50-383 Wrocław, Poland.
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Drive, Tallahassee, FL 32310, USA.
| | - Alina Bieńko
- Faculty of Chemistry, University of Wrocław, 14, F. Joliot-Curie, 50-383 Wrocław, Poland.
| | - Tadeusz Lis
- Faculty of Chemistry, University of Wrocław, 14, F. Joliot-Curie, 50-383 Wrocław, Poland.
| | - Adam Jezierski
- Faculty of Chemistry, University of Wrocław, 14, F. Joliot-Curie, 50-383 Wrocław, Poland.
| | - Marta Krawczyk
- Faculty of Pharmacy, Wrocław Medical University, 211 Borowska, 50-556 Wrocław, Poland
| |
Collapse
|
22
|
Chen SY, Lv W, Cui HH, Chen L, Zhang YQ, Chen XT, Wang Z, Ouyang ZW, Yan H, Xue ZL. Magnetic anisotropies and slow magnetic relaxation of three tetrahedral tetrakis(pseudohalido)–cobalt( ii) complexes. NEW J CHEM 2021. [DOI: 10.1039/d1nj01916c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Magnetic anisotropies and slow magnetic relaxation of three homoleptic cobalt(ii) complexes with different pseudohalide ligands were studied via magnetometry, HFEPR and theoretical calculations.
Collapse
Affiliation(s)
- Shu-Yang Chen
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Wei Lv
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Hui-Hui Cui
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Lei Chen
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, China
| | - Yi-Quan Zhang
- Jiangsu Key Laboratory for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing 210023, China
| | - Xue-Tai Chen
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Zhenxing Wang
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zhong-Wen Ouyang
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Hong Yan
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Zi-Ling Xue
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee, 37996, USA
| |
Collapse
|
23
|
Świtlicka A, Machura B, Bieńko A, Kozieł S, Bieńko DC, Rajnák C, Boča R, Ozarowski A, Ozerov M. Non-traditional thermal behavior of Co( ii) coordination networks showing slow magnetic relaxation. Inorg Chem Front 2021. [DOI: 10.1039/d1qi00667c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Three new Co(ii) coordination polymers show the DC magnetic data consistent with the S = 3/2 spin system with large zero-field splitting D > 0, which was confirmed by HF EPR and FIRMS measurements.
Collapse
Affiliation(s)
- Anna Świtlicka
- Department of Crystallography, Institute of Chemistry, University of Silesia, 9 Szkolna St., 40-006 Katowice, Poland
| | - Barbara Machura
- Department of Crystallography, Institute of Chemistry, University of Silesia, 9 Szkolna St., 40-006 Katowice, Poland
| | - Alina Bieńko
- Faculty of Chemistry, University of Wroclaw, 14 F. Joliot-Curie, 50-383 Wroclaw, Poland
| | - Sandra Kozieł
- Faculty of Chemistry, University of Wroclaw, 14 F. Joliot-Curie, 50-383 Wroclaw, Poland
| | - Dariusz C. Bieńko
- Faculty of Chemistry, Wroclaw University of Technology, Wybrzeze Wyspiańskiego 27, 50-370 Wroclaw, Poland
| | - Cyril Rajnák
- Department of Chemistry, Faculty of Natural Sciences, University of SS Cyril and Methodius, 917 01 Trnava, Slovakia
| | - Roman Boča
- Department of Chemistry, Faculty of Natural Sciences, University of SS Cyril and Methodius, 917 01 Trnava, Slovakia
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, USA
| | - Mykhaylo Ozerov
- National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, USA
| |
Collapse
|
24
|
Greer SM, Gramigna KM, Thomas CM, Stoian SA, Hill S. Insights into Molecular Magnetism in Metal-Metal Bonded Systems as Revealed by a Spectroscopic and Computational Analysis of Diiron Complexes. Inorg Chem 2020; 59:18141-18155. [PMID: 33253552 DOI: 10.1021/acs.inorgchem.0c02605] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A pair of bimetallic compounds featuring Fe-Fe bonds, [Fe(iPrNPPh2)3FeR] (R = PMe3, ≡NtBu), have been investigated using High-Frequency Electron Paramagnetic Resonance (HFEPR) as well as field- and temperature-dependent 57Fe nuclear γ resonance (Mössbauer) spectroscopy. To gain insight into the local site electronic structure, we have concurrently studied a compound containing a single Fe(II) in a geometry analogous to that of one of the dimer sites. Our spectroscopic studies have allowed for the assessment of the electronic structure via the determination of the zero-field splitting and 57Fe hyperfine parameters for the entire series. We also report on our efforts to correlate structure with physical properties in metal-metal bonded systems using ligand field theory guided by quantum chemical calculations. Through the insight gained in this study, we discuss strategies for the design of single-molecule magnets based on polymetallic compounds linked via direct metal-metal bonds.
Collapse
Affiliation(s)
- Samuel M Greer
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States.,Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Kathryn M Gramigna
- Department of Chemistry, Brandeis University, Waltham, Massachusetts 02453, United States
| | - Christine M Thomas
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Sebastian A Stoian
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844, United States
| | - Stephen Hill
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States.,Department of Physics, Florida State University, Tallahassee, Florida 32306, United States
| |
Collapse
|
25
|
Chakarawet K, Atanasov M, Marbey J, Bunting PC, Neese F, Hill S, Long JR. Strong Electronic and Magnetic Coupling in M 4 (M = Ni, Cu) Clusters via Direct Orbital Interactions between Low-Coordinate Metal Centers. J Am Chem Soc 2020; 142:19161-19169. [PMID: 33111523 DOI: 10.1021/jacs.0c08460] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present an extensive study of tetranuclear transition-metal cluster compounds M4(NPtBu3)4 and [M4(NPtBu3)4][B(C6F5)4] (M = Ni, Cu; tBu = tert-butyl), which feature low-coordinate metal centers and direct metal-metal orbital overlap. X-ray diffraction, electrochemical, magnetic, spectroscopic, and computational analysis elucidate the nature of the bonding interactions in these clusters and the impact of these interactions on the electronic and magnetic properties. Direct orbital overlap results in strongly coupled, large-spin ground states in the [Ni4(NPtBu3)4]+/0 clusters and fully delocalized, spin-correlated electrons. Correlated electronic structure calculations confirm the presence of ferromagnetic ground states that arise from direct exchange between magnetic orbitals, and, in the case of the neutral cluster, itinerant electron magnetism similar to that in metallic ferromagnets. The cationic nickel cluster also possesses large magnetic anisotropy exemplified by a large, positive axial zero-field splitting parameter of D = +7.95 or +9.2 cm-1, as determined by magnetometry or electron paramagnetic resonance spectroscopy, respectively. The [Ni4(NPtBu3)4]+ cluster is also the first molecule with easy-plane magnetic anisotropy to exhibit zero-field slow magnetic relaxation, and under a small applied field, it exhibits relaxation exclusively through an Orbach mechanism with a spin relaxation barrier of 16 cm-1. The S = 1/2 complex [Cu4(NPtBu3)4]+ exhibits slow magnetic relaxation via a Raman process on the millisecond time scale, supporting the presence of slow relaxation via an Orbach process in the nickel analogue. Overall, this work highlights the unique electronic and magnetic properties that can be realized in metal clusters featuring direct metal-metal orbital interactions between low-coordinate metal centers.
Collapse
Affiliation(s)
| | - Mihail Atanasov
- Max-Planck Institut für Kohlenforschung, Mülheim an der Ruhr D-45470, Germany.,Institute of General and Inorganic Chemistry, Bulgarian Academy of Science, Akad. Georgi Bontchev, Street 11, 1113 Sofia, Bulgaria
| | - Jonathan Marbey
- Department of Physics and National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | | | - Frank Neese
- Max-Planck Institut für Kohlenforschung, Mülheim an der Ruhr D-45470, Germany
| | - Stephen Hill
- Department of Physics and National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Jeffrey R Long
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| |
Collapse
|
26
|
Kumar P, SantaLucia DJ, Kaniewska-Laskowska K, Lindeman SV, Ozarowski A, Krzystek J, Ozerov M, Telser J, Berry JF, Fiedler AT. Probing the Magnetic Anisotropy of Co(II) Complexes Featuring Redox-Active Ligands. Inorg Chem 2020; 59:16178-16193. [DOI: 10.1021/acs.inorgchem.0c01812] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Praveen Kumar
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
| | - Daniel J. SantaLucia
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Kinga Kaniewska-Laskowska
- Department of Inorganic Chemistry, Faculty of Chemistry, Gdańsk University of Technology, Gdańsk PL-80-233, Poland
| | - Sergey V. Lindeman
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - J. Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Mykhaylo Ozerov
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Joshua Telser
- Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605, United States
| | - John F. Berry
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Adam T. Fiedler
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
| |
Collapse
|
27
|
A 3D interpenetrated Co(II)-glutarate coordination polymer: Synthesis, crystal structure, magnetic and adsorption properties. Inorganica Chim Acta 2020. [DOI: 10.1016/j.ica.2020.119791] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
28
|
Saber MR, Thirunavukkuarasu K, Greer SM, Hill S, Dunbar KR. Magnetostructural and EPR Studies of Anisotropic Vanadium trans-Dicyanide Molecules. Inorg Chem 2020; 59:13262-13269. [PMID: 32869626 DOI: 10.1021/acs.inorgchem.0c01595] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A series of trans-dicyanide vanadium(III) compounds based on acetylacetonate, (PPN)[VIII(acac)2(CN)2]·(PPN)Cl·2MeCN (1), and salen ligands, (Et4N)[VIII(salen)(CN)2] (2a), (PPN)[VIII(MeOsalen)(CN)2]·DMF·2MeCN (3), and (PPN)[VIII(salphen)(CN)2]·DMF (4) [salen = N,N'-ethylenebis(salicyl-imine), MeOsalen = N,N'-ethylenebis(methoxysalicylimine), salphen = N,N'-phenylenebis(salicyl-imine), and PPN = bis(triphenylphosphine)iminium], were prepared and structurally characterized. High-field EPR studies reveal that the complexes exhibit moderate magnetic anisotropy with positive D values of +5.70, +3.80, +4.05, and +3.99 cm-1 for 1-4, respectively.
Collapse
Affiliation(s)
- Mohamed R Saber
- Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012, United States.,Chemistry Department, Faculty of Science, Fayoum University, Fayoum 63514, Egypt
| | - Komalavalli Thirunavukkuarasu
- Department of Physics, Florida A&M University, Tallahassee, Florida 32307, United States.,National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Samuel M Greer
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States.,Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Stephen Hill
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States.,Department of Physics, Florida State University, Tallahassee, Florida 32306, United States
| | - Kim R Dunbar
- Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012, United States
| |
Collapse
|
29
|
Sanakis Y, Krzystek J, Maganas D, Grigoropoulos A, Ferentinos E, Kostakis MG, Petroulea V, Pissas M, Thirunavukkuarasu K, Wernsdorfer W, Neese F, Kyritsis P. Magnetic Properties and Electronic Structure of the S = 2 Complex [Mn III{(OPPh 2) 2N} 3] Showing Field-Induced Slow Magnetization Relaxation. Inorg Chem 2020; 59:13281-13294. [PMID: 32897702 DOI: 10.1021/acs.inorgchem.0c01636] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The high-spin S = 2 Mn(III) complex [Mn{(OPPh2)2N}3] (1Mn) exhibits field-induced slow relaxation of magnetization (Inorg. Chem. 2013, 52, 12869). Magnetic susceptibility and dual-mode X-band electron paramagnetic resonance (EPR) studies revealed a negative value of the zero-field-splitting (zfs) parameter D. In order to explore the magnetic and electronic properties of 1Mn in detail, a combination of experimental and computational studies is presented herein. Alternating-current magnetometry on magnetically diluted samples (1Mn/1Ga) of 1Mn in the diamagnetic gallium analogue, [Ga{(OPPh2)2N}3], indicates that the slow relaxation behavior of 1Mn is due to the intrinsic properties of the individual molecules of 1Mn. Investigation of the single-crystal magnetization of both 1Mn and 1Mn/1Ga by a micro-SQUID device reveals hysteresis loops below 1 K. Closed hysteresis loops at a zero direct-current magnetic field are observed and attributed to fast quantum tunneling of magnetization. High-frequency and -field EPR (HFEPR) spectroscopic studies reveal that, apart from the second-order zfs terms (D and E), fourth-order terms (B4m) are required in order to appropriately describe the magnetic properties of 1Mn. These studies provide accurate spin-Hamiltonian (sH) parameters of 1Mn, i.e., zfs parameters |D| = 3.917(5) cm-1, |E| = 0.018(4) cm-1, B04 = B42 = 0, and B44 = (3.6 ± 1.7) × 10-3 cm-1 and g = [1.994(5), 1.996(4), 1.985(4)], and confirm the negative sign of D. Parallel-mode X-band EPR studies on 1Mn/1Ga and CH2Cl2 solutions of 1Mn probe the electronic-nuclear hyperfine interactions in the solid state and solution. The electronic structure of 1Mn is investigated by quantum-chemical calculations by employing recently developed computational protocols that are grounded on ab initio wave function theory. From computational analysis, the contributions of spin-spin and spin-orbit coupling to the magnitude of D are obtained. The calculations provide also computed values of the fourth-order zfs terms B4m, as well as those of the g and hyperfine interaction tensor components. In all cases, a very good agreement between the computed and experimentally determined sH parameters is observed. The magnetization relaxation properties of 1Mn are rationalized on the basis of the composition of the ground-state wave functions in the absence or presence of an external magnetic field.
Collapse
Affiliation(s)
- Yiannis Sanakis
- Institute of Nanoscience and Nanotechnolgy, National Centre of Scientific Research "Demokritos", Aghia Paraskevi 15310, Attiki, Greece
| | - J Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Dimitrios Maganas
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Alexios Grigoropoulos
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, 15771 Athens, Greece
| | - Eleftherios Ferentinos
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, 15771 Athens, Greece
| | - Marios G Kostakis
- Analytical Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens,15771 Athens, Greece
| | - Vasiliki Petroulea
- Institute of Nanoscience and Nanotechnolgy, National Centre of Scientific Research "Demokritos", Aghia Paraskevi 15310, Attiki, Greece
| | - Michael Pissas
- Institute of Nanoscience and Nanotechnolgy, National Centre of Scientific Research "Demokritos", Aghia Paraskevi 15310, Attiki, Greece
| | | | - Wolfgang Wernsdorfer
- Physikalisches Institut, Karlsruher Institut für Technologie, Wolfgang-Gaede-Strasse 1, 76131 Karlsruhe, Germany.,Institute of Quantum Materials and Technologies, Karlsruher Institut für Technologie, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Frank Neese
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Panayotis Kyritsis
- Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, 15771 Athens, Greece
| |
Collapse
|
30
|
Premužić D, Hołyńska M, Ozarowski A, Pietzonka C, Roseborough A, Stoian SA. Model Dimeric Manganese(IV) Complexes Featuring Terminal Tris-hydroxotetraazaadamantane and Various Bridging Ligands. Inorg Chem 2020; 59:10768-10784. [PMID: 32687708 DOI: 10.1021/acs.inorgchem.0c01242] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A series of model dinuclear manganese(IV) complexes of the general formula [(H3COH)(L')MnIV(μ-L)2MnIV(L')(HOCH3)] is presented. These compounds feature capping 4,6,10-trihydroxo-3,5,7-trimethyl-1,4,6,10-tetraazaadamantane ligands derived from a polydentate oxime compound (L'). The bridging ligands L include azide (1), methoxide (2), and oxalate (3) anions. The magnetic properties and high-field (HF) EPR spectra of 1-3 were studied in detail and revealed varying weak antiferromagnetic coupling and modest zero-field splitting (ZFS) of the local quartet spin sites. Our HF EPR studies provide insight into the dimer ZFS, including determination of the corresponding parameters by giant spin approach for methoxido-bridged complex 2. Furthermore, the physicochemical properties of 1-3 were studied using IR, UV-vis, and electrochemical (cyclic voltammetry) methods. Theoretical exchange coupling constants were obtained using broken-symmetry (BS) density functional theory (DFT). Computational estimates of the local quartet ground spins state ZFSs of 1-3 were obtained using coupled-perturbed (CP) DFT and complete active space self-consistent field (CASSCF) calculations with n-electron valence state perturbation theory (NEVPT2) corrections. We found that the CP DFT calculations which used the B3LYP functional and models derived experimental structures performed best in reproducing both the magnitude and the sign of the experimental D values. Moreover, our computational investigation of 1-3 suggests that we observe metals sites which have an increased +3 character and are supported by redox noninnocent 4,6,10-trihydroxo-3,5,7-trimethyl-1,4,6,10-tetraazaadamantane ligands. The latter conclusion is further corroborated by the observation that the free ligand can be readily oxidized to yield a NO-based radical.
Collapse
Affiliation(s)
- Dejan Premužić
- Fachbereich Chemie and Wissenschaftliches Zentrum für Materialwissenschaften(WZMW), Philipps-Universität Marburg Hans-Meerwein-Straße, Marburg D-35043, Germany
| | - Małgorzata Hołyńska
- Fachbereich Chemie and Wissenschaftliches Zentrum für Materialwissenschaften(WZMW), Philipps-Universität Marburg Hans-Meerwein-Straße, Marburg D-35043, Germany
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Clemens Pietzonka
- Fachbereich Chemie and Wissenschaftliches Zentrum für Materialwissenschaften(WZMW), Philipps-Universität Marburg Hans-Meerwein-Straße, Marburg D-35043, Germany
| | - Alexander Roseborough
- Department of Chemistry, University of Idaho, 875 Perimeter Drive, Moscow, Idaho 83844, United States
| | - Sebastian A Stoian
- Department of Chemistry, University of Idaho, 875 Perimeter Drive, Moscow, Idaho 83844, United States
| |
Collapse
|
31
|
Das Gupta S, Stewart RL, Chen DT, Abboud KA, Cheng HP, Hill S, Christou G. Long-Range Ferromagnetic Exchange Interactions Mediated by Mn-Ce IV-Mn Superexchange Involving Empty 4f Orbitals. Inorg Chem 2020; 59:8716-8726. [PMID: 32573216 DOI: 10.1021/acs.inorgchem.0c00332] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Reactions involving reductive aggregation of MnO4- in methanol in the presence of CeIV and an excess of carboxylic acid have led to the synthesis of structurally related Ce/Mn clusters, [Ce3Mn5O8(OMe)(O2CBut)13(MeOH)] (1) and [Ce2Mn3O5(O2CPh)9(MeOH)3] (2), containing at least one {Mn2Ce2O4} cubane unit. The cores of both clusters contain Mnx units separated by three (1) or two (2) CeIV ions. Fits of variable-temperature, solid-state dc and ac magnetic susceptibility data reveal dominant ferromagnetic interactions within 1 and 2, resulting in the maximum S = 17/2 and S = 5 ground state spins, respectively, and thus suggesting significant ferromagnetic (F) interactions between the Mnx units that are ≥6 Å apart and separated by four intervening bonds through diamagnetic CeIV. Fits of magnetic susceptibility data also revealed unusual long-range F interactions, and this finding was further supported by high-field EPR measurements and simulations. Density functional theory calculations and a Wannier function analysis confirm long-range interactions and indicate a Mn-Ce-Mn superexchange pathway via Mn-d/Ce-f orbital overlap/hybridization.
Collapse
Affiliation(s)
- Sayak Das Gupta
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
| | - Robert L Stewart
- National High Magnetic Field Laboratory and Department of Physics, Florida State University, Tallahassee, Florida 32310, United States
| | - Dian-Teng Chen
- Department of Physics, University of Florida, Gainesville, Florida 32611, United States
| | - Khalil A Abboud
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
| | - Hai-Ping Cheng
- Department of Physics, University of Florida, Gainesville, Florida 32611, United States
| | - Stephen Hill
- National High Magnetic Field Laboratory and Department of Physics, Florida State University, Tallahassee, Florida 32310, United States
| | - George Christou
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
| |
Collapse
|
32
|
Manganese tetraphenylporphyrin bromide and iodide. Studies of structures and magnetic properties. Polyhedron 2020. [DOI: 10.1016/j.poly.2020.114488] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
|
33
|
Impert O, Kozakiewicz A, Wrzeszcz G, Katafias A, Bieńko A, van Eldik R, Ozarowski A. Characterization of a Mixed-Valence Ru(II)/Ru(III) Ion-Pair Complex. Unexpected High-Frequency Electron Paramagnetic Resonance Evidence for Ru(III)-Ru(III) Dimer Coupling. Inorg Chem 2020; 59:8609-8619. [PMID: 32441928 DOI: 10.1021/acs.inorgchem.0c01068] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In this contribution, we report the synthesis and full characterization of the first mixed-valence Ru(II)/Ru(III) ion-pair complex, [RuII(bipy)2(pic)]+[cis-RuIIICl2(pic)2]-, in the solid state and in aqueous solution, where bipy = 2,2'-bipyridine and pic- = picolinate. In addition, unexpected high-frequency electron paramagnetic resonance evidence for interactions between two neighboring Ru(III) ions, resulting in a triplet state, S = 1, was found.
Collapse
Affiliation(s)
- Olga Impert
- Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100 Toruń, Poland
| | - Anna Kozakiewicz
- Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100 Toruń, Poland
| | - Grzegorz Wrzeszcz
- Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100 Toruń, Poland
| | - Anna Katafias
- Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100 Toruń, Poland
| | - Alina Bieńko
- Faculty of Chemistry, University of Wroclaw, 14 F. Joliot-Curie, 50-383 Wroclaw, Poland
| | - Rudi van Eldik
- Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100 Toruń, Poland.,Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland.,Department of Chemistry and Pharmacy, University of Erlangen-Nuremberg, Egerlandstrasse 1, 91058 Erlangen, Germany
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310 United States
| |
Collapse
|
34
|
Zolnhofer EM, Wijeratne GB, Jackson TA, Fortier S, Heinemann FW, Meyer K, Krzystek J, Ozarowski A, Mindiola DJ, Telser J. Electronic Structure and Magnetic Properties of a Titanium(II) Coordination Complex. Inorg Chem 2020; 59:6187-6201. [PMID: 32279487 DOI: 10.1021/acs.inorgchem.0c00311] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Stable coordination complexes of TiII (3d2) are relatively uncommon, but are of interest as synthons for low oxidation state titanium complexes for application as potential catalysts and reagents for organic synthesis. Specifically, high-spin TiII ions supported by redox-inactive ligands are still quite rare due to the reducing power of this soft ion. Among such TiII complexes is trans-[TiCl2(tmeda)2], where tmeda = N,N,N',N'-tetramethylethane-1,2-diamine. This complex was first reported by Gambarotta and co-workers almost 30 years ago, but it was not spectroscopically characterized and theoretical investigation by quantum chemical theory (QCT) was not feasible at that time. As part of our interest in low oxidation state early transition metal complexes, we have revisited this complex and report a modified synthesis and a low temperature (100 K) crystal structure that differs slightly from that originally reported at ambient temperature. We have used magnetometry, high-frequency and -field EPR (HFEPR), and variable-temperature variable-field magnetic circular dichroism (VTVH-MCD) spectroscopies to characterize trans-[TiCl2(tmeda)2]. These techniques yield the following S = 1 spin Hamiltonian parameters for the complex: D = -5.23(1) cm-1, E = -0.88(1) cm-1, (E/D = 0.17), g = [1.86(1), 1.94(2), 1.77(1)]. This information, in combination with electronic transitions from MCD, was used as input for both classical ligand-field theory (LFT) and detailed QCT studies, the latter including both density functional theory (DFT) and ab initio methods. These computational methods are seldom applied to paramagnetic early transition metal complexes, particularly those with S > 1/2. Our studies provide a complete picture of the electronic structure of this complex that can be put into context with the few other high-spin and mononuclear TiII species characterized to date.
Collapse
Affiliation(s)
- Eva M Zolnhofer
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander University Erlangen-Nürnberg (FAU), 91058 Erlangen, Germany
| | - Gayan B Wijeratne
- Department of Chemistry, University of Kansas, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States
| | - Timothy A Jackson
- Department of Chemistry, University of Kansas, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States
| | - Skye Fortier
- Department of Chemistry and Molecular Structure Center, Indiana University, Bloomington, Indiana 47405, United States
| | - Frank W Heinemann
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander University Erlangen-Nürnberg (FAU), 91058 Erlangen, Germany
| | - Karsten Meyer
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander University Erlangen-Nürnberg (FAU), 91058 Erlangen, Germany
| | - J Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Daniel J Mindiola
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Joshua Telser
- Department of Biological, Physical and Health Sciences, Roosevelt University, Chicago, Illinois 60605, United States
| |
Collapse
|
35
|
Obaleye JA, Ajibola AA, Bernardus VB, Hosten EC, Ozarowski A. Synthesis, spectroscopic, structural and antimicrobial studies of a dimeric complex of copper(II) with trichloroacetic acid and metronidazole. Inorganica Chim Acta 2020. [DOI: 10.1016/j.ica.2019.119404] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
36
|
Ferromagnetically-coupled, triangular, [Bu4N]2[CuII3(μ3-Br)2(μ-4-O2N-pz)3Br3] complex revisited: The effect of coordinated halides on spin relaxation properties. Polyhedron 2020. [DOI: 10.1016/j.poly.2019.114258] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
37
|
Krzystek J, Schnegg A, Aliabadi A, Holldack K, Stoian SA, Ozarowski A, Hicks SD, Abu-Omar MM, Thomas KE, Ghosh A, Caulfield KP, Tonzetich ZJ, Telser J. Advanced Paramagnetic Resonance Studies on Manganese and Iron Corroles with a Formal d 4 Electron Count. Inorg Chem 2020; 59:1075-1090. [PMID: 31909979 DOI: 10.1021/acs.inorgchem.9b02635] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Metallocorroles wherein the metal ion is MnIII and formally FeIV are studied here using field- and frequency-domain electron paramagnetic resonance techniques. The MnIII corrole, Mn(tpfc) (tpfc = 5,10,15-tris(pentafluorophenyl)corrole trianion), exhibits the following S = 2 zero-field splitting (zfs) parameters: D = -2.67(1) cm-1, |E| = 0.023(5) cm-1. This result and those for other MnIII tetrapyrroles indicate that when D ≈ - 2.5 ± 0.5 cm-1 for 4- or 5-coordinate and D ≈ - 3.5 ± 0.5 cm-1 for 6-coordinate complexes, the ground state description is [MnIII(Cor3-)]0 or [MnIII(P2-)]+ (Cor = corrole, P = porphyrin). The situation for formally FeIV corroles is more complicated, and it has been shown that for Fe(Cor)X, when X = Ph (phenyl), the ground state is a spin triplet best described by [FeIV(Cor3-)]+, but when X = halide, the ground state corresponds to [FeIII(Cor•2-)]+, wherein an intermediate spin (S = 3/2) FeIII is antiferromagnetically coupled to a corrole radical dianion (S = 1/2) to also give an S = 1 ground state. These two valence isomers can be distinguished by their zfs parameters, as determined here for Fe(tpc)X, X = Ph, Cl (tpc = 5,10,15-triphenylcorrole trianion). The complex with axial phenyl gives D = 21.1(2) cm-1, while that with axial chloride gives D = 14.6(1) cm-1. The D value for Fe(tpc)Ph is in rough agreement with the range of values reported for other FeIV complexes. In contrast, the D value for Fe(tpc)Cl is inconsistent with an FeIV description and represents a different type of iron center. Computational studies corroborate the zfs for the two types of iron corrole complexes. Thus, the zfs of metallocorroles can be diagnostic as to the electronic structure of a formally high oxidation state metallocorrole, and by extension to metalloporphyrins, although such studies have yet to be performed.
Collapse
Affiliation(s)
- J Krzystek
- National High Magnetic Field Laboratory , Florida State University , Tallahassee , Florida 32310 , United States
| | - Alexander Schnegg
- EPR Research Group , Max Planck Institute for Chemical Energy Conversion , Stiftstraße 34-36 , D-45470 Mülheim Ruhr , Germany.,Berlin Joint EPR Laboratory , Helmholtz-Zentrum Berlin , Kekulestraße 5 , D-12489 Berlin , Germany
| | - Azar Aliabadi
- Berlin Joint EPR Laboratory , Helmholtz-Zentrum Berlin , Kekulestraße 5 , D-12489 Berlin , Germany
| | - Karsten Holldack
- Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung am Elektronenspeicherring BESSY II , Albert-Einstein-Straße 15 , D-12489 Berlin , Germany
| | - Sebastian A Stoian
- Department of Chemistry , University of Idaho , Moscow , Idaho 83844 , United States
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory , Florida State University , Tallahassee , Florida 32310 , United States
| | - Scott D Hicks
- Department of Chemistry , Purdue University , West Lafayette , Indiana 47907 , United States
| | - Mahdi M Abu-Omar
- Departments of Chemistry and Biochemistry , University of California , Santa Barbara , California 93106-9510 , United States
| | - Kolle E Thomas
- Department of Chemistry , UiT-The Arctic University of Norway , N-9037 Tromsø , Norway
| | - Abhik Ghosh
- Department of Chemistry , UiT-The Arctic University of Norway , N-9037 Tromsø , Norway
| | - Kenneth P Caulfield
- Department of Chemistry , University of Texas at San Antonio (UTSA) , One UTSA Circle , San Antonio , Texas 78249 , United States
| | - Zachary J Tonzetich
- Department of Chemistry , University of Texas at San Antonio (UTSA) , One UTSA Circle , San Antonio , Texas 78249 , United States
| | - Joshua Telser
- Department of Biological, Physical, and Health Sciences , Roosevelt University , Chicago , Illinois 60605 , United States
| |
Collapse
|
38
|
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.
Collapse
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.
| |
Collapse
|
39
|
Misochko EY, Akimov AV, Korchagin DV, Nehrkorn J, Ozerov M, Palii AV, Clemente-Juan JM, Aldoshin SM. Purely Spectroscopic Determination of the Spin Hamiltonian Parameters in High-Spin Six-Coordinated Cobalt(II) Complexes with Large Zero-Field Splitting. Inorg Chem 2019; 58:16434-16444. [DOI: 10.1021/acs.inorgchem.9b02195] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | | | - Joscha Nehrkorn
- National High Magnetic Field Laboratory & Florida State University, Tallahassee, Florida, United States
- Max Planck Institute for Chemical Energy Conversion, Mülheim/Ruhr, Germany
| | - Mykhaylo Ozerov
- National High Magnetic Field Laboratory & Florida State University, Tallahassee, Florida, United States
| | - Andrew V. Palii
- Institute of Problems of Chemical Physics of RAS, Chernogolovka, Russia
- Institute of Applied Physics, Chisinau, Moldova
| | | | | |
Collapse
|
40
|
Escobar LBL, Guedes GP, Soriano S, Marbey J, Hill S, Novak MA, Vaz MGF. Synthesis, Magnetic and High-Field EPR Investigation of Two Tetranuclear Ni II-Based Complexes. Inorg Chem 2019; 58:14420-14428. [PMID: 31625735 DOI: 10.1021/acs.inorgchem.9b01816] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Two tetranuclear compounds with a cubane-like structure were synthesized from a one-pot reaction between NiII and 2,2,6,6-tetramethyl-3,5-heptanedione (Hdpm) for 1 or 4,4,4-trifluoro-1-phenyl-1,3-butanedione (Hbta) for 2 in the presence of sodium methoxide. The crystal structures of both compounds have been determined by single-crystal X-ray diffraction, and their magnetic properties have been studied by SQUID magnetometry as well as by high-field electron paramagnetic resonance (HFEPR) spectroscopy. For 1, the temperature dependence of the magnetic susceptibility can be fitted by taking into account Ni···Ni ferromagnetic interactions, which leads to an S = 4 ground-state spin. For 2, both antiferromagnetic and ferromagnetic interactions are present. However, the latter are dominant, which also leads to an S = 4 ground-state spin, in good agreement with the HFEPR study.
Collapse
Affiliation(s)
- Lívia B L Escobar
- Instituto de Química , Universidade Federal Fluminense , Niterói , Rio de Janeiro 24020-141 , Brazil.,NHMFL, Florida State University , Tallahassee , Florida 32310 , United States
| | - Guilherme P Guedes
- Instituto de Química , Universidade Federal Fluminense , Niterói , Rio de Janeiro 24020-141 , Brazil
| | - Stéphane Soriano
- Instituto de Física , Universidade Federal Fluminense , Niterói , Rio de Janeiro 24210-346 , Brazil
| | - Jonathan Marbey
- NHMFL, Florida State University , Tallahassee , Florida 32310 , United States.,Department of Physics , Florida State University , Tallahassee , Florida 32306 , United States
| | - Stephen Hill
- NHMFL, Florida State University , Tallahassee , Florida 32310 , United States.,Department of Physics , Florida State University , Tallahassee , Florida 32306 , United States
| | - Miguel A Novak
- Instituto de Física , Universidade Federal do Rio de Janeiro , Rio de Janeiro , 21941-972 , Brazil
| | - Maria G F Vaz
- Instituto de Química , Universidade Federal Fluminense , Niterói , Rio de Janeiro 24020-141 , Brazil
| |
Collapse
|
41
|
Nehrkorn J, Bonke SA, Aliabadi A, Schwalbe M, Schnegg A. Examination of the Magneto-Structural Effects of Hangman Groups on Ferric Porphyrins by EPR. Inorg Chem 2019; 58:14228-14237. [PMID: 31599581 DOI: 10.1021/acs.inorgchem.9b02348] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ferric hangman porphyrins are bioinspired models for haem hydroperoxidase enzymes featuring an acid/base group in close vicinity to the metal center, which results in improved catalytic activity for reactions requiring O-O bond activation. These functional biomimics are examined herein with a combination of EPR techniques to determine the effects of the hanging group on the electronics of the ferric center. These results are compared to those for ferric octaethylporphyrin chloride [Fe(OEP)Cl], tetramesitylporphyrin chloride [Fe(TMP)Cl], and the pentafluorophenyl derivative [Fe(TPFPP)Cl], which were also examined herein to study the electronic effects of various substituents. Frequency-domain Fourier-transform THz-EPR combined with field domain EPR in a broad frequency range from 9.5 to 629 GHz allowed the determination of zero-field splitting parameters, revealing minor rhombicity E/D and D values in a narrow range of 6.24(8) to 6.85(5) cm-1. Thus, the hangman porphyrins display D values in the expected range for ferric porphyrin chlorides, though D appears to be correlated with the Fe-Cl bond length. Extrapolating this trend to the ferric hangman porphyrin chlorides, for which no crystal structure has been reported, indicates a slightly elongated Fe-Cl bond length compared to the non-hangman equivalent.
Collapse
Affiliation(s)
- Joscha Nehrkorn
- EPR Research Group , Max-Planck-Institut für Chemische Energiekonversion , Stiftstraße 34-36 , 45470 Mülheim an der Ruhr , Germany.,Institut für Anorganische und Angewandte Chemie , Universität Hamburg , Martin-Luther-King-Platz 6 , 20146 Hamburg , Germany.,Institut Nanospektroskopie , Helmholtz-Zentrum Berlin für Materialien und Energie , Kekuléstraße 5 , 12489 Berlin , Germany
| | - Shannon A Bonke
- EPR Research Group , Max-Planck-Institut für Chemische Energiekonversion , Stiftstraße 34-36 , 45470 Mülheim an der Ruhr , Germany.,Institut Nanospektroskopie , Helmholtz-Zentrum Berlin für Materialien und Energie , Kekuléstraße 5 , 12489 Berlin , Germany
| | - Azar Aliabadi
- Institut Nanospektroskopie , Helmholtz-Zentrum Berlin für Materialien und Energie , Kekuléstraße 5 , 12489 Berlin , Germany
| | - Matthias Schwalbe
- Institut für Chemie , Humboldt Universität zu Berlin , Brook-Taylor-Straße 2 , 12489 Berlin , Germany
| | - Alexander Schnegg
- EPR Research Group , Max-Planck-Institut für Chemische Energiekonversion , Stiftstraße 34-36 , 45470 Mülheim an der Ruhr , Germany.,Institut Nanospektroskopie , Helmholtz-Zentrum Berlin für Materialien und Energie , Kekuléstraße 5 , 12489 Berlin , Germany
| |
Collapse
|
42
|
Cui HH, Zhang YQ, Chen XT, Wang Z, Xue ZL. Magnetic anisotropy and slow magnetic relaxation processes of cobalt(ii)-pseudohalide complexes. Dalton Trans 2019; 48:10743-10752. [PMID: 31250855 DOI: 10.1039/c9dt00644c] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Three mononuclear six-coordinate Co(ii)-pseudohalide complexes [Co(L)X2] with two N-donor pseudohalido coligands occupying the cis-positions (X = NCS- (1), NCSe- (2) or N(CN)2- (3)), and a five-coordinate complex [Co(L)(NCO)][B(C6H5)4] (4) [L = 1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecane (12-TMC)] have been prepared and structurally characterized. Easy-plane magnetic anisotropy for 1-3 and easy-axis anisotropy for 4 were revealed via the analyses of the direct-current magnetic data, high-frequency and -field EPR (HFEPR) spectra and ab initio theoretical calculations. They display slow magnetic relaxations under an external applied dc field. Typically, two slow relaxation processes were found in 1 and 2 while only one relaxation process occurs in 3 and 4. The Raman-like mechanism is found to be dominant in the studied temperature range in 1. For 2-4, the Raman process is dominant in the low temperature region, while the Orbach mechanism dominates in the high temperature range.
Collapse
Affiliation(s)
- Hui-Hui Cui
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
| | - Yi-Quan Zhang
- Jiangsu Key Laboratory for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing 210023, China
| | - Xue-Tai Chen
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
| | - Zhenxing Wang
- Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zi-Ling Xue
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA
| |
Collapse
|
43
|
Hay MA, Sarkar A, Craig GA, Bhaskaran L, Nehrkorn J, Ozerov M, Marriott KER, Wilson C, Rajaraman G, Hill S, Murrie M. In-depth investigation of large axial magnetic anisotropy in monometallic 3d complexes using frequency domain magnetic resonance and ab initio methods: a study of trigonal bipyramidal Co(ii). Chem Sci 2019; 10:6354-6361. [PMID: 31341591 PMCID: PMC6601423 DOI: 10.1039/c9sc00987f] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 05/19/2019] [Indexed: 11/21/2022] Open
Abstract
The magnetic properties of 3d monometallic complexes can be tuned through geometric control, owing to their synthetic accessibility and relative structural simplicity. Monodentate ligands offer great potential for fine-tuning the coordination environment to engineer both the axial and rhombic zero-field splitting (ZFS) parameters. In [CoCl3(DABCO)(HDABCO)] (1), the trigonal bipyramidal Co(ii) centre has two bulky axial ligands and three equatorial chloride ligands. An in-depth experimental and theoretical study of 1 reveals a large easy-plane magnetic anisotropy (+ve D) with a negligible rhombic zero-field splitting (E) due to the strict axial symmetry imposed by the C 3 symmetric ligand and trigonal space group. The large easy-plane magnetic anisotropy (D = +44.5 cm-1) is directly deduced using high-field EPR and frequency-domain magnetic resonance (FDMR) studies. Ab initio calculations reveal a large positive contribution to the D term arising from ground state/excited state mixing of the 4E'' states at ∼4085 cm-1 and a minor contribution from the spin-flip transition as well. The nature of the slow relaxation in 1 is elucidated through analysis of the rates of relaxation of magnetisation, taking into account Raman and direct spin-lattice relaxation processes and Quantum Tunnelling of the Magnetisation (QTM). The terms relating to the direct process and QTM were found based on the fit of the field-dependence of τ at 2 K. Subsequently, these were used as fixed parameters in the fit of the temperature-dependence of τ to obtain the Raman terms. This experimental-theoretical investigation provides further insight into the power of FDMR and ab initio methods for the thorough investigation of magnetic anisotropy. Thus, these results contribute to design criteria for high magnetic anisotropy systems.
Collapse
Affiliation(s)
- Moya A Hay
- WestCHEM , School of Chemistry , University of Glasgow , University Avenue , Glasgow , G12 8QQ , UK .
| | - Arup Sarkar
- Department of Chemistry , Institute of Technology Bombay , Powai , Mumbai , Maharashtra 400 076 , India .
| | - Gavin A Craig
- WestCHEM , School of Chemistry , University of Glasgow , University Avenue , Glasgow , G12 8QQ , UK .
| | - Lakshmi Bhaskaran
- Department of Physics , Florida State University , Tallahassee , FL 32306 , USA .
- National High Magnetic Field Laboratory , 1800 E. Paul Dirac Drive Tallahassee , FL 32310 , USA
| | - Joscha Nehrkorn
- National High Magnetic Field Laboratory , 1800 E. Paul Dirac Drive Tallahassee , FL 32310 , USA
- Max Planck Institute for Chemical Energy Conversion , Stiftstr. 34-36 , 45470 Mülheim an der Ruhr , Germany
| | - Mykhailo Ozerov
- National High Magnetic Field Laboratory , 1800 E. Paul Dirac Drive Tallahassee , FL 32310 , USA
| | - Katie E R Marriott
- WestCHEM , School of Chemistry , University of Glasgow , University Avenue , Glasgow , G12 8QQ , UK .
| | - Claire Wilson
- WestCHEM , School of Chemistry , University of Glasgow , University Avenue , Glasgow , G12 8QQ , UK .
| | - Gopalan Rajaraman
- Department of Chemistry , Institute of Technology Bombay , Powai , Mumbai , Maharashtra 400 076 , India .
| | - Stephen Hill
- Department of Physics , Florida State University , Tallahassee , FL 32306 , USA .
- National High Magnetic Field Laboratory , 1800 E. Paul Dirac Drive Tallahassee , FL 32310 , USA
| | - Mark Murrie
- WestCHEM , School of Chemistry , University of Glasgow , University Avenue , Glasgow , G12 8QQ , UK .
| |
Collapse
|
44
|
Gagnon DM, Hadley RC, Ozarowski A, Nolan EM, Britt RD. High-Field EPR Spectroscopic Characterization of Mn(II) Bound to the Bacterial Solute-Binding Proteins MntC and PsaA. J Phys Chem B 2019; 123:4929-4934. [PMID: 31117618 DOI: 10.1021/acs.jpcb.9b03633] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
During infection, the bacterial pathogens Staphylococcus aureus and Streptococcus pneumoniae employ ATP-binding cassette (ABC) transporters to acquire Mn(II), an essential nutrient, from the host environment. Staphylococcal MntABC and streptococcal PsaABC attract the attention of the biophysical and bacterial pathogenesis communities because of their established importance during infection. Previous biophysical examination of Mn(II)-MntC and Mn(II)-PsaA using continuous-wave (≈9 GHz) electron paramagnetic resonance (EPR) spectroscopy revealed broad, difficult-to-interpret spectra (Hadley et al. J. Am. Chem. Soc. 2018, 140, 110-113). Herein, we employ high-frequency (>90 GHz), high-field (>3 T) EPR spectroscopy to investigate the Mn(II)-binding sites of these proteins and determine the spin Hamiltonian parameters. Our analyses demonstrate that the zero-field splitting (ZFS) is large for Mn(II)-MntC and Mn(II)-PsaA at +2.72 and +2.87 GHz, respectively. The measured 55Mn hyperfine coupling values for Mn(II)-MntC and Mn(II)-PsaA of 241 and 236 MHz, respectively, demonstrate a more covalent interaction between Mn(II) and the protein compared to Mn(II) in aqueous solution (≈265 MHz). These studies indicate that MntC and PsaA bind Mn(II) in a similar coordination geometry. Comparison of the ZFS values determined herein with those ascertained for other Mn(II) proteins suggests that the Mn(II)-MntC and Mn(II)-PsaA coordination spheres are not five-coordinate in solution.
Collapse
Affiliation(s)
- Derek M Gagnon
- Department of Chemistry , University of California Davis , Davis , California 95616 , United States
| | - Rose C Hadley
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory , Florida State University , Tallahassee , Florida 32310 , United States
| | - Elizabeth M Nolan
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - R David Britt
- Department of Chemistry , University of California Davis , Davis , California 95616 , United States
| |
Collapse
|
45
|
Hadley RC, Gagnon DM, Ozarowski A, Britt RD, Nolan EM. Murine Calprotectin Coordinates Mn(II) at a Hexahistidine Site with Ca(II)-Dependent Affinity. Inorg Chem 2019; 58:13578-13590. [PMID: 31145609 DOI: 10.1021/acs.inorgchem.9b00763] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Manganese is an essential metal ion that bacterial pathogens need to acquire from the vertebrate host during infection. In the mammalian nutritional immunity strategy to combat bacterial infection, the host restricts bacterial access to Mn(II) by sequestering this metal nutrient using the protein calprotectin (CP). The role of murine calprotectin (mCP) in Mn(II) sequestration has been demonstrated in vivo, but the molecular basis of this function has not been evaluated. Herein, biochemical assays and electron paramagnetic resonance (EPR) spectroscopy are employed to characterize the Mn(II) binding properties of mCP. We report that mCP has one high-affinity Mn(II) binding site. This site is a His6 site composed of His17 and His27 of mS100A8 and His92, His97, His105, and His107 of mS100A9. Similar to the human ortholog (hCP), Ca(II) binding to the EF-hand domains of mCP enhances the Mn(II) affinity of the protein; however, this effect requires ≈10-fold more Ca(II) than was previously observed for hCP. Mn(II) coordination to the His6 site also promotes self-association of two mCP heterodimers to form a heterotetramer. Low-temperature X-band EPR spectroscopy revealed a nearly octahedral Mn(II) coordination sphere for the Mn(II)-His6 site characterized by the zero-field splitting parameters D = 525 MHz and E/D = 0.3. Further electron-nuclear double resonance studies with globally 15N-labeled mCP provided hyperfine couplings from the coordinating ε-nitrogen atoms of the His ligands (aiso = 4.3 MHz) as well as the distal δ-nitrogen atoms (aiso = 0.25 MHz). Mn(II) competition assays between mCP and two bacterial Mn(II) solute-binding proteins, staphylococcal MntC and streptococcal PsaA, showed that mCP outcompetes both proteins for Mn(II) under conditions of excess Ca(II). In total, this work provides the first coordination chemistry study of mCP and reveals striking similarities in the Mn(II) coordination sphere as well as notable differences in the Ca(II) sensitivity and oligomerization behavior between hCP and mCP.
Collapse
Affiliation(s)
- Rose C Hadley
- Department of Chemistry , Massachusetts Institute of Technology (MIT) , Cambridge , Massachusetts 02139 , United States
| | - Derek M Gagnon
- Department of Chemistry , University of California, Davis , Davis , California 95616 , United States
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory , Florida State University , Tallahassee , Florida 32310 , United States
| | - R David Britt
- Department of Chemistry , University of California, Davis , Davis , California 95616 , United States
| | - Elizabeth M Nolan
- Department of Chemistry , Massachusetts Institute of Technology (MIT) , Cambridge , Massachusetts 02139 , United States
| |
Collapse
|
46
|
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
| |
Collapse
|
47
|
Bucinsky L, Breza M, Malček M, Powers DC, Hwang SJ, Krzystek J, Nocera DG, Telser J. High-Frequency and -Field EPR (HFEPR) Investigation of a Pseudotetrahedral CrIV Siloxide Complex and Computational Studies of Related CrIVL4 Systems. Inorg Chem 2019; 58:4907-4920. [DOI: 10.1021/acs.inorgchem.8b03512] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Lukas Bucinsky
- Institute of Physical Chemistry and Chemical Physics, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, SK-81237 Bratislava, Slovakia
| | - Martin Breza
- Institute of Physical Chemistry and Chemical Physics, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, SK-81237 Bratislava, Slovakia
| | - Michal Malček
- Institute of Physical Chemistry and Chemical Physics, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, SK-81237 Bratislava, Slovakia
| | - David C. Powers
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Seung Jun Hwang
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - J. Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Daniel G. Nocera
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Joshua Telser
- Department of Biological, Physical and Health Sciences, Roosevelt University, Chicago, Illinois 60605, United States
| |
Collapse
|
48
|
Banerjee A, Tolla AS, Stjepanovic S, Sevilla MD, Goodsell JL, Angerhofer A, Brennessel WW, Loloee R, Chavez FA. Structural, Spectroscopic, Electrochemical, and Magnetic Properties for Manganese(II) Triazamacrocyclic Complexes. Inorganica Chim Acta 2019; 486:546-555. [PMID: 33981118 PMCID: PMC8112617 DOI: 10.1016/j.ica.2018.11.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We report the synthesis of [Mn(tacud)2](OTf)2 (1) (tacud = 1,4,8-triazacycloundecane), [Mn(tacd)2](OTf)2 (2) (tacd = 1,4,7-triazacyclodecane), and [Mn(tacn)2](OTf)2 (3) (tacn = 1,4,7-triazacyclononane). Electrochemical measurements on the MnIII/II redox couple show that complex 1 has the largest anodic potential of the set (E 1/2 = 1.16 V vs NHE, ΔE p = 106 mV) compared to 2 (E 1/2 = 0.95 V, ΔE p = 108 mV) and 3 (E 1/2 = 0.93 V, ΔE p = 96 mV). This is due to the fact that 1 has the fewest 5-membered chelate rings and thus is least stabilized. Magnetic studies of 1-3 revealed that all complexes remain high spin throughout the temperature range investigated (2 - 300 K). X-band EPR investigations in methanol glass indicated that the manganese(II) centers for 2 and 3 resided in a more distorted octahedral geometric configuration compared to 1. To ease spectral interpretation and extract ZFS parameters, we performed high-frequency high-field EPR (HFEPR) at frequencies above 200 GHz and a field of 7.5 T. Simulation of the spectral data yielded g = 2.0013 and D = -0.031 cm-1 for 1, g = 2.0008, D = -0.0824 cm-1, |E/D| = 0.12 for 2, and g = 2.00028, D = -0.0884 cm-1 for 3. These results are consistent with 3 possessing the most distorted geometry. Calculations (PBE0/6-31G(d)) were performed on 1-3. Results show that 1 has the largest HOMO-LUMO gap energy (6.37 eV) compared to 2 (6.12 eV) and 3 (6.26 eV). Complex 1 also has the lowest HOMO energies indicating higher stability.
Collapse
Affiliation(s)
- Atanu Banerjee
- Department of Chemistry, Oakland University, Rochester, MI 48309-4477, USA
| | - Azam S Tolla
- Department of Chemistry, Oakland University, Rochester, MI 48309-4477, USA
| | | | - Michael D Sevilla
- Department of Chemistry, Oakland University, Rochester, MI 48309-4477, USA
| | - Justin L Goodsell
- Department of Chemistry, University of Florida, Gainesville, FL 32611-7200, USA
| | | | | | - Reza Loloee
- Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824-1322, USA
| | - Ferman A Chavez
- Department of Chemistry, Oakland University, Rochester, MI 48309-4477, USA
| |
Collapse
|
49
|
Masegosa A, Palacios MA, Ruiz E, Gómez-Coca S, Krzystek J, Moreno JM, Colacio E. Dinuclear CoIIYIIIvs. tetranuclear CoII2YIII2 complexes: the effect of increasing molecular size on magnetic anisotropy and relaxation dynamics. Dalton Trans 2019; 48:14873-14884. [DOI: 10.1039/c9dt02969a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The lower distortion of the CoII ions in the new tetranuclear CoII2YIII2 complex leads to a larger magnetic anisotropy than in its CoIIYIII counterparts, whereas its larger size and flexibility seem to promote a faster relaxation dynamic.
Collapse
Affiliation(s)
- Alberto Masegosa
- Departamento de Química Inorgánica
- Facultad de Ciencias
- Universidad de Granada
- 18071 Granada
- Spain
| | - María A. Palacios
- Departamento de Química Inorgánica
- Facultad de Ciencias
- Universidad de Granada
- 18071 Granada
- Spain
| | - Eliseo Ruiz
- Departament de Química Inorgànica and Institut de Recerca de Química Teòrica i Computacional
- Universitat de Barcelona
- Barcelona E-08028
- Spain
| | - Silvia Gómez-Coca
- Departament de Química Inorgànica and Institut de Recerca de Química Teòrica i Computacional
- Universitat de Barcelona
- Barcelona E-08028
- Spain
| | - J. Krzystek
- National High Magnetic Field Laboratory
- Florida State University
- Tallahassee
- USA
| | - José M. Moreno
- Departamento de Química Inorgánica
- Facultad de Ciencias
- Universidad de Granada
- 18071 Granada
- Spain
| | - Enrique Colacio
- Departamento de Química Inorgánica
- Facultad de Ciencias
- Universidad de Granada
- 18071 Granada
- Spain
| |
Collapse
|
50
|
Shova S, Vlad A, Cazacu M, Krzystek J, Ozarowski A, Malček M, Bucinsky L, Rapta P, Cano J, Telser J, Arion VB. Dinuclear manganese(iii) complexes with bioinspired coordination and variable linkers showing weak exchange effects: a synthetic, structural, spectroscopic and computation study. Dalton Trans 2019; 48:5909-5922. [DOI: 10.1039/c8dt04596h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
High-resolution HFEPR indicates weak exchange interactions between MnIII ions in agreement with DFT calculations.
Collapse
Affiliation(s)
- Sergiu Shova
- Inorganic Polymers Department
- “Petru Poni” Institute of Macromolecular Chemistry
- Iasi 700487
- Romania
| | - Angelica Vlad
- Inorganic Polymers Department
- “Petru Poni” Institute of Macromolecular Chemistry
- Iasi 700487
- Romania
| | - Maria Cazacu
- Inorganic Polymers Department
- “Petru Poni” Institute of Macromolecular Chemistry
- Iasi 700487
- Romania
| | - J. Krzystek
- National High Magnetic Field Laboratory
- Florida State University
- Tallahassee
- USA
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory
- Florida State University
- Tallahassee
- USA
| | - Michal Malček
- Institute of Physical Chemistry and Chemical Physics
- Slovak University of Technology in Bratislava
- 81237 Bratislava
- Slovak Republic
| | - Lukas Bucinsky
- Institute of Physical Chemistry and Chemical Physics
- Slovak University of Technology in Bratislava
- 81237 Bratislava
- Slovak Republic
| | - Peter Rapta
- Institute of Physical Chemistry and Chemical Physics
- Slovak University of Technology in Bratislava
- 81237 Bratislava
- Slovak Republic
| | - Joan Cano
- Institut de Ciència Molecular
- Universitat de València
- 46980 Paterna
- Spain
| | - Joshua Telser
- Department of Biological
- Physical and Health Sciences
- Roosevelt University
- Chicago
- USA
| | - Vladimir B. Arion
- Institute of Inorganic Chemistry of the University of Vienna
- A1090 Vienna
- Austria
| |
Collapse
|