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Giraldo JN, Hrubý J, Vavrečková Š, Fellner OF, Havlíček L, Henry D, de Silva S, Herchel R, Bartoš M, Šalitroš I, Santana VT, Barbara P, Nemec I, Neugebauer P. Tetracoordinate Co(II) complexes with semi-coordination as stable single-ion magnets for deposition on graphene. Phys Chem Chem Phys 2023; 25:29516-29530. [PMID: 37901907 PMCID: PMC10631493 DOI: 10.1039/d3cp01426f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 10/03/2023] [Indexed: 10/31/2023]
Abstract
We present a theoretical and experimental study of two tetracoordinate Co(II)-based complexes with semi-coordination interactions, i.e., non-covalent interactions involving the central atom. We argue that such interactions enhance the thermal and structural stability of the compounds, making them appropriate for deposition on substrates, as demonstrated by their successful deposition on graphene. DC magnetometry and high-frequency electron spin resonance (HF-ESR) experiments revealed an axial magnetic anisotropy and weak intermolecular antiferromagnetic coupling in both compounds, supported by theoretical predictions from complete active space self-consistent field calculations complemented by N-electron valence state second-order perturbation theory (CASSCF-NEVPT2), and broken-symmetry density functional theory (BS-DFT). AC magnetometry demonstrated that the compounds are field-induced single-ion magnets (SIMs) at applied static magnetic fields, with slow relaxation of magnetization governed by a combination of quantum tunneling, Orbach, and direct relaxation mechanisms. The structural stability under ambient conditions and after deposition was confirmed by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Theoretical modeling by DFT of different configurations of these systems on graphene revealed n-type doping of graphene originating from electron transfer from the deposited molecules, confirmed by electrical transport measurements and Raman spectroscopy.
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Affiliation(s)
- Jorge Navarro Giraldo
- Central European Institute of Technology, CEITEC BUT, Purkyňova 656/123, 61200 Brno, Czech Republic.
| | - Jakub Hrubý
- Central European Institute of Technology, CEITEC BUT, Purkyňova 656/123, 61200 Brno, Czech Republic.
| | - Šárka Vavrečková
- Central European Institute of Technology, CEITEC BUT, Purkyňova 656/123, 61200 Brno, Czech Republic.
- Institute of Physical Engineering, Faculty of Mechanical Engineering, Brno University of Technology, Technická 2, 61669 Brno, Czech Republic
| | - Ondřej F Fellner
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 77147 Olomouc, Czech Republic
| | - Lubomír Havlíček
- Central European Institute of Technology, CEITEC BUT, Purkyňova 656/123, 61200 Brno, Czech Republic.
- Institute of Physics of Materials, Czech Academy of Sciences, Žižkova 22, 61662 Brno, Czech Republic
| | - DaVonne Henry
- Department of Physics, Georgetown University, Washington, DC, USA
| | - Shehan de Silva
- Department of Physics, Georgetown University, Washington, DC, USA
| | - Radovan Herchel
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 77147 Olomouc, Czech Republic
| | - Miroslav Bartoš
- Central European Institute of Technology, CEITEC BUT, Purkyňova 656/123, 61200 Brno, Czech Republic.
| | - Ivan Šalitroš
- Central European Institute of Technology, CEITEC BUT, Purkyňova 656/123, 61200 Brno, Czech Republic.
- Department of Inorganic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Bratislava SK-81237, Slovakia
| | - Vinicius T Santana
- Central European Institute of Technology, CEITEC BUT, Purkyňova 656/123, 61200 Brno, Czech Republic.
| | - Paola Barbara
- Department of Physics, Georgetown University, Washington, DC, USA
| | - Ivan Nemec
- Central European Institute of Technology, CEITEC BUT, Purkyňova 656/123, 61200 Brno, Czech Republic.
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 77147 Olomouc, Czech Republic
| | - Petr Neugebauer
- Central European Institute of Technology, CEITEC BUT, Purkyňova 656/123, 61200 Brno, Czech Republic.
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2
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Gupta SK, Rao SV, Demeshko S, Dechert S, Bill E, Atanasov M, Neese F, Meyer F. Air-stable four-coordinate cobalt(ii) single-ion magnets: experimental and ab initio ligand field analyses of correlations between dihedral angles and magnetic anisotropy. Chem Sci 2023; 14:6355-6374. [PMID: 37325133 PMCID: PMC10266464 DOI: 10.1039/d3sc00813d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 05/12/2023] [Indexed: 06/17/2023] Open
Abstract
For single-ion magnets (SIMs), understanding the effects of the local coordination environment and ligand field on magnetic anisotropy is key to controlling their magnetic properties. Here we present a series of tetracoordinate cobalt(ii) complexes of the general formula [FL2Co]X2 (where FL is a bidentate diamido ligand) whose electron-withdrawing -C6F5 substituents confer stability under ambient conditions. Depending on the cations X, these complexes adopt structures with greatly varying dihedral twist angle δ between the N-Co-N' chelate planes in the solid state (48.0 to 89.2°). AC and DC field magnetic susceptibility measurements show this to translate into very different magnetic properties, the axial zero-field splitting (ZFS) parameter D ranging from -69 cm-1 to -143 cm-1 with substantial or negligible rhombic component E, respectively. A close to orthogonal arrangement of the two N,N'-chelating σ- and π-donor ligands at the Co(ii) ion is found to raise the energy barrier for magnetic relaxation to above 400 K. Multireference ab initio methods were employed to describe the complexes' electronic structures, and the results were analyzed within the framework of ab initio ligand field theory to probe the nature of the metal-ligand bonding and spin-orbit coupling. A relationship between the energy gaps of the first few electronic transitions and the ZFS was established, and the ZFS was correlated with the dihedral angle δ as well as with the metal-ligand bonding variations, viz. the two angular overlap parameters eσ and eπs. These findings not only give rise to a Co(ii) SIM showing open hysteresis up to 3.5 K at a sweep rate of 30 Oe s-1, but they also provide design guidelines for Co(ii) complexes with favorable SIM signatures or even switchable magnetic relaxation properties.
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Affiliation(s)
- Sandeep K Gupta
- Institut für Anorganische Chemie, Universität Göttingen Tammannstrasse 4 37077 Göttingen Germany
| | - Shashank V Rao
- Max Planck Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
| | - Serhiy Demeshko
- Institut für Anorganische Chemie, Universität Göttingen Tammannstrasse 4 37077 Göttingen Germany
| | - Sebastian Dechert
- Institut für Anorganische Chemie, Universität Göttingen Tammannstrasse 4 37077 Göttingen Germany
| | - Eckhard Bill
- Max Planck Institute for Chemical Energy Conversion Stiftstrasse 34-36 45470 Mülheim an der Ruhr Germany
| | - Mihail Atanasov
- Max Planck Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
- Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences Akad. Georgi Bontchev Street 11 1113 Sofia Bulgaria
| | - Frank Neese
- Max Planck Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
| | - Franc Meyer
- Institut für Anorganische Chemie, Universität Göttingen Tammannstrasse 4 37077 Göttingen Germany
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3
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Pohle MH, Böhme M, Lohmiller T, Ziegenbalg S, Blechschmidt L, Görls H, Schnegg A, Plass W. Magnetic Anisotropy and Relaxation of Pseudotetrahedral [N 2 O 2 ] Bis-Chelate Cobalt(II) Single-Ion Magnets Controlled by Dihedral Twist Through Solvomorphism. Chemistry 2023; 29:e202202966. [PMID: 36468847 DOI: 10.1002/chem.202202966] [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: 09/22/2022] [Revised: 12/04/2022] [Accepted: 12/05/2022] [Indexed: 12/07/2022]
Abstract
The methanol solvomorph 1 ⋅ 2MeOH of the cobalt(II) complex [Co(LSal,2-Ph )2 ] (1) with the sterically demanding Schiff-base ligand 2-(([1,1'-biphenyl]-2-ylimino)methyl)phenol (HLSal,2-Ph ) shows the thus far largest dihedral twist distortion between the two chelate planes compared to an ideal pseudotetrahedral arrangement. The cobalt(II) ion in 1 ⋅ 2MeOH exhibits an easy-axis anisotropy leading to a spin-reversal barrier of 55.3 cm-1 , which corresponds to an increase of about 17 % induced by the larger dihedral twist compared to the solvent-free complex 1. The magnetic relaxation for 1 ⋅ 2MeOH is significantly slower compared to 1. An in-depth frequency-domain Fourier-transform (FD-FT) THz-EPR study not only allowed the direct measurement of the magnetic transition between the two lowest Kramers doublets for the cobalt(II) complexes, but also revealed the presence of spin-phonon coupling. Interestingly, a similar dihedral twist correlation is also observed for a second pair of cobalt(II)-based solvomorphs, which could be benchmarked by FD-FT THz-EPR.
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Affiliation(s)
- Maximilian H Pohle
- Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstraße 8, 07743, Jena, Germany
| | - Michael Böhme
- Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstraße 8, 07743, Jena, Germany
| | - Thomas Lohmiller
- EPR4Energy Joint Lab, Department Spins in Energy Conversion and Quantum Information Science, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 16, 12489, Berlin, Germany.,present address: Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489, Berlin, Germany
| | - Sven Ziegenbalg
- Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstraße 8, 07743, Jena, Germany
| | - Louis Blechschmidt
- Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstraße 8, 07743, Jena, Germany
| | - Helmar Görls
- Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstraße 8, 07743, Jena, Germany
| | - Alexander Schnegg
- EPR4Energy Joint Lab, Department Spins in Energy Conversion and Quantum Information Science, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 16, 12489, Berlin, Germany.,EPR Research Group, MPI for Chemical Energy Conversion, Stiftstr. 34-36, 45470, Mülheim an der Ruhr, Germany
| | - Winfried Plass
- Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstraße 8, 07743, Jena, Germany
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Kumar Sahu P, Kharel R, Shome S, Goswami S, Konar S. Understanding the unceasing evolution of Co(II) based single-ion magnets. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2022.214871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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5
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Sauza-de la Vega A, Pandharkar R, Stroscio GD, Sarkar A, Truhlar DG, Gagliardi L. Multiconfiguration Pair-Density Functional Theory for Chromium(IV) Molecular Qubits. JACS AU 2022; 2:2029-2037. [PMID: 36186551 PMCID: PMC9516709 DOI: 10.1021/jacsau.2c00306] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 08/19/2022] [Accepted: 08/19/2022] [Indexed: 05/30/2023]
Abstract
Pseudotetrahedral organometallic complexes containing chromium(IV) and aryl ligands have been experimentally identified as promising molecular qubit candidates. Here we present a computational protocol based on multiconfiguration pair-density functional theory for computing singlet-triplet gaps and zero-field splitting (ZFS) parameters in Cr(IV) aryl complexes. We find that two multireference methods, multistate complete active space second-order perturbation theory (MS-CASPT2) and hybrid multistate pair-density functional theory (HMS-PDFT), perform better than Kohn-Sham density functional theory for singlet-triplet gaps. Despite the very small values of the ZFS parameters, both multireference methods performed qualitatively well. MS-CASPT2 and HMS-PDFT performed particularly well for predicting the trend in the ratio of the rhombic and axial ZFS parameters, |E/D|. We have also investigated the dependence and sensitivity of the calculated ZFS parameters on the active space and the molecular geometry. The methodologies outlined here can guide future prediction of ZFS parameters in molecular qubit candidates.
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Affiliation(s)
- Arturo Sauza-de la Vega
- Department
of Chemistry, Pritzker School of Molecular Engineering, James Franck
Institute, Chicago Center for Theoretical Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Riddhish Pandharkar
- Department
of Chemistry, Pritzker School of Molecular Engineering, James Franck
Institute, Chicago Center for Theoretical Chemistry, University of Chicago, Chicago, Illinois 60637, United States
- Argonne
National Laboratory, Lemont, Illinois 60439, United States
| | - Gautam D. Stroscio
- Department
of Chemistry, Pritzker School of Molecular Engineering, James Franck
Institute, Chicago Center for Theoretical Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Arup Sarkar
- Department
of Chemistry, Pritzker School of Molecular Engineering, James Franck
Institute, Chicago Center for Theoretical Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Donald G. Truhlar
- Department
of Chemistry, Chemical Theory Center, and Minnesota Supercomputing
Institute, University of Minnesota, Minneapolis, Minnesota 55455−0431, United States
| | - Laura Gagliardi
- Department
of Chemistry, Pritzker School of Molecular Engineering, James Franck
Institute, Chicago Center for Theoretical Chemistry, University of Chicago, Chicago, Illinois 60637, United States
- Argonne
National Laboratory, Lemont, Illinois 60439, United States
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Ferreira PS, Malta JF, Bandeira NAG, Allgaier A, van Slageren J, Paixão JA, Almeida M, Pereira LCJ, Gomes PT. Enhancing SIM behaviour in a mononuclear tetrahedral [Co( N, N'-2-iminopyrrolyl) 2] complex. Chem Commun (Camb) 2022; 58:9682-9685. [PMID: 35950347 DOI: 10.1039/d2cc03511a] [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
A new homoleptic Co(II) complex bearing two highly sterically congested 2-formiminopyrrolyl N,N'-chelating ligands is reported, displaying slow relaxation of the magnetisation at zero static (DC) field. This compound shows a large value for the zero-field splitting (ZFS) parameter D of -42.6(4) cm-1 leading to a spin-reversal energy barrier Ueff of 85 cm-1.
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Affiliation(s)
- Patrícia S Ferreira
- Centro de Química Estrutural, Institute of Molecular Sciences, Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001, Lisboa, Portugal. .,Centro de Ciências e Tecnologias Nucleares, Departamento de Engenharia e Ciências Nucleares, Instituto Superior Técnico, Universidade de Lisboa, 2695-066, Bobadela LRS, Portugal.
| | - José F Malta
- Centro de Ciências e Tecnologias Nucleares, Departamento de Engenharia e Ciências Nucleares, Instituto Superior Técnico, Universidade de Lisboa, 2695-066, Bobadela LRS, Portugal. .,CFisUC - Centro de Física da Universidade de Coimbra, Departamento de Física, Universidade de Coimbra, 3004-516, Coimbra, Portugal
| | - Nuno A G Bandeira
- BioISI - Biosystems & Integrative Sciences Institute, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, Ed. C8, 1749-016, Lisboa, Portugal.
| | - Alexander Allgaier
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, Stuttgart, D-70569, Germany.
| | - Joris van Slageren
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, Stuttgart, D-70569, Germany.
| | - José A Paixão
- CFisUC - Centro de Física da Universidade de Coimbra, Departamento de Física, Universidade de Coimbra, 3004-516, Coimbra, Portugal
| | - Manuel Almeida
- Centro de Ciências e Tecnologias Nucleares, Departamento de Engenharia e Ciências Nucleares, Instituto Superior Técnico, Universidade de Lisboa, 2695-066, Bobadela LRS, Portugal.
| | - Laura C J Pereira
- Centro de Ciências e Tecnologias Nucleares, Departamento de Engenharia e Ciências Nucleares, Instituto Superior Técnico, Universidade de Lisboa, 2695-066, Bobadela LRS, Portugal.
| | - Pedro T Gomes
- Centro de Química Estrutural, Institute of Molecular Sciences, Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001, Lisboa, Portugal.
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7
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Chen Y, Yang Q, Peng G, Zhang YQ, Ren XM. Influence of F-position and solvent on coordination geometry and single ion magnet behavior of Co(II) complexes. Dalton Trans 2021; 50:13830-13840. [PMID: 34522941 DOI: 10.1039/d1dt02148f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Three mononuclear Co(II) complexes with the compositions of [Co(L1)2] (1), [Co(L2)2(CH3CN)] (2) and [Co(L3)2] (3) (HL1 = 2-((E)-(2-fluorobenzylimino)methyl)-4,6-dibromophenol, HL2 = 2-((E)-(3-fluorobenzylimino)methyl)-4,6-dibromophenol and HL3 = 2-((E)-(4-fluorobenzylimino)methyl)-4,6-dibromophenol) were prepared and structurally determined. The changes in the F-positions in the ligands and solvents led to the formation of these products with various coordination geometries. Both complexes 1 and 3 are four-coordinated and their coordination geometries can be described as tetrahedron and seesaw, whereas complex 2 is five coordinated with a coordination configuration in between trigonal bipyramid and square pyramid. Static magnetic studies reveal that all these complexes exhibit considerable easy-axis magnetic anisotropy. The easy-axis magnetic anisotropy of 1 and 3 mainly derives from the first quartet excited state, whereas that of 2 primarily originates from the first, third and fourth quartet excited states established by theoretical calculations. All the resulting complexes display field-induced slow magnetic relaxation. Complex 3 represents the first Co(II) single ion magnet with a seesaw coordination geometry. Ab initio calculations predict that the magnetic anisotropy will enhance when the seesaw coordination geometry varies from distortion to regulation.
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Affiliation(s)
- Yue Chen
- School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, P. R. China.
| | - Qi Yang
- School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, P. R. China.
| | - Guo Peng
- School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, P. R. China.
| | - Yi-Quan Zhang
- Jiangsu Key Laboratory for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing 210023, P. R. China.
| | - Xiao-Ming Ren
- School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, P. R. China.
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8
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Kharwar AK, Mondal A, Sarkar A, Rajaraman G, Konar S. Modulation of Magnetic Anisotropy and Exchange Interaction in Phenoxide-Bridged Dinuclear Co(II) Complexes. Inorg Chem 2021; 60:11948-11956. [PMID: 34314144 DOI: 10.1021/acs.inorgchem.1c00956] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report a new class of four dimeric Co(II) complexes [Co2(bbpen)(X)2] (H2bbpen = N,N'-bis(2-hydroxybenzyl)-N,N'-bis(2-methylpyridyl)ethylenediamine) [X- = SCN (1), Cl (2), Br (3), and I (4)] with different coordination geometry of two Co(II) centers (trigonal-prismatic and pseudo-tetrahedral) and their magnetic study. Interestingly, the two Co(II) centers show two different types of magnetic anisotropy. State of the art ab initio CASSCF analysis reveals that the six-coordinate or the trigonal-prismatic Co(II) center possesses a consistently large negative axial zero-field splitting (negative D) parameter (∼-60 cm-1), while the four-coordinate or the pseudo-tetrahedral Co(II) center exhibits a range of D values from +13 to -23 cm-1. Ab initio calculations employing the lines model were used to estimate the magnetic exchange as both the Co(II) centers possess significant magnetic anisotropy. All the complexes display rare ferromagnetic interaction, and the strength of this interaction decreases as the ligand field on the pseudo-tetrahedral Co(II) center decreases from SCN- > Cl- > Br- > I-.
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Affiliation(s)
- Ajit Kumar Kharwar
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Bhopal, Bypass Road, Bhauri, Bhopal 462066, India
| | - Arpan Mondal
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Bhopal, Bypass Road, Bhauri, Bhopal 462066, India
| | - Arup Sarkar
- 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
| | - Sanjit Konar
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Bhopal, Bypass Road, Bhauri, Bhopal 462066, India
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Wang M, Xu H, Sun T, Cui H, Zhang YQ, Chen L, Tang Y. Optimal N–Co–N bite angle for enhancing the magnetic anisotropy of zero-field Co(II) single-ion magnets in tetrahedral [N4] coordination environment. J SOLID STATE CHEM 2021. [DOI: 10.1016/j.jssc.2021.122209] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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10
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Akintola O, Buchholz A, Görls H, Plass W. Modulator Induced Formation of a Neutral Framework Based on Trinuclear Cobalt(II) Clusters and Nitrilotribenzoic Acid: Synthesis, Magnetism, and Sorption Properties. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Oluseun Akintola
- Institut für Anorganische und Analytische Chemie Friedrich-Schiller-Universität Jena Humboldtstr. 8 07743 Jena Germany
| | - Axel Buchholz
- Institut für Anorganische und Analytische Chemie Friedrich-Schiller-Universität Jena Humboldtstr. 8 07743 Jena Germany
| | - Helmar Görls
- Institut für Anorganische und Analytische Chemie Friedrich-Schiller-Universität Jena Humboldtstr. 8 07743 Jena Germany
| | - Winfried Plass
- Institut für Anorganische und Analytische Chemie Friedrich-Schiller-Universität Jena Humboldtstr. 8 07743 Jena Germany
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11
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Banerjee A, Banerjee S, Gómez García CJ, Benmansour S, Chattopadhyay S. Field-induced single molecule magnet behavior of a dinuclear cobalt(II) complex: a combined experimental and theoretical study. Dalton Trans 2020; 49:16778-16790. [PMID: 33174540 DOI: 10.1039/d0dt02158j] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two dinuclear cobalt(ii) complexes, [(dmso)CoIIL1(μ-(m-NO2)C6H4COO)CoII(NCS)] (1) and [(dmso)CoIIL2(μ-(m-NO2)C6H4COO)CoII(NCS)] (2) [dmso = dimethylsulfoxide, H2L1 = (2,2-dimethyl-1,3-propanediyl)bis(iminomethylene)bis(6-methoxyphenol) and H2L2 = (2,2-dimethyl-1,3-propanediyl)bis(iminomethylene)bis(6-ethoxyphenol)] have been synthesized and structurally characterized by single-crystal X-ray diffraction, magnetic-susceptibility measurements and various spectroscopic techniques. Each complex contains a cobalt(ii) center with a slightly distorted octahedral geometry and a second cobalt(ii) center with a distorted trigonal prismatic one. To obtain insight into the physical nature of weak non-covalent interactions, we have extensively used the Bader's quantum theory of atoms-in-molecules (QTAIM). In addition, the non-covalent interaction reduced density gradient (NCI-RDG) methods established the presence of such non-covalent intermolecular interactions. Variable temperature magnetic susceptibility measurements show that both cobalt centers in each complex are in the high spin state (S = 3/2) and both complexes show weak ferromagnetic couplings through the double phenoxido bridges (J = 3.36(3) cm-1 in 1 and 4.56(2) cm-1 in 2). The magnetic properties of both complexes can be fitted to a Co(ii) dimer model including similar orbital reduction factors (α = -0.94(1) for 1 and -0.85(1) for 2) although different zero field splitting parameters D(1) = 11.0(4) cm-1 and D(2) = 19.5(4) cm-1 in 1 and D(1) = 8.2(4) cm-1 and D(2) = -1.3(4) cm-1 in 2. AC magnetic measurements reveal that the CoII2 unit in complex 2 exhibits field-induced slow relaxation of the magnetization at low temperatures and high frequencies.
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Affiliation(s)
- Abhisek Banerjee
- Department of Chemistry, Inorganic Section, Jadavpur University, Kolkata - 700032, India.
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12
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Jochim A, Rams M, Böhme M, Ceglarska M, Plass W, Näther C. Thermodynamically metastable chain and stable layered Co(NCS) 2 coordination polymers: thermodynamic relations and magnetic properties. Dalton Trans 2020; 49:15310-15322. [PMID: 33118568 DOI: 10.1039/d0dt03227a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Reaction of Co(NCS)2 with 4-bromopyridine leads to the formation of discrete complexes with the composition Co(NCS)2(4-bromopyridine)4·(CH3CN)0.67 (1), Co(NCS)2(4-bromopyridine)2(H2O)2 (2), Co(NCS)2(4-bromopyridine)2(CH3OH)2 (3) and Co(NCS)2(4-bromopyridine)2(CH3CN)2 (4). Upon heating compounds 2 and 4 transform into a crystalline product with the composition Co(NCS)2(4-bromopyridine)2 (5-I) that also can easily be obtained from solution. In this compound, the Co cations are linked by single μ-1,3-bridging thiocyanate anions into layers. Thermal decomposition of 3 leads to a second isomer (5-II), which is thermodynamically metastable and can also be synthesized from solution under kinetic control. In contrast to 5-I, the Co cations are linked by pairs of anionic ligands into linear chains. The magnetic exchange is very weak in 5-I, but much stronger and ferromagnetic along the linear chains in 5-II. AF ordering in 5-II is reached at 3.05 K, and magnetic relaxation is observed at the metamagnetic transition with an Arrhenius barrier of 17.1(3) cm-1. Ab initio computational studies reveal a different type of magnetic anisotropy to be present in the two crystallographically - independent Co centers in 5-II.
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Affiliation(s)
- Aleksej Jochim
- Institut für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Straße 2, 24118 Kiel, Germany.
| | - Michał Rams
- Institute of Physics, Jagiellonian University, Łojasiewicza 11, 30-348 Krakow, Poland
| | - Michael Böhme
- Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstr. 8, 07743 Jena, Germany
| | - Magdalena Ceglarska
- Institute of Physics, Jagiellonian University, Łojasiewicza 11, 30-348 Krakow, Poland
| | - Winfried Plass
- Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstr. 8, 07743 Jena, Germany
| | - Christian Näther
- Institut für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Straße 2, 24118 Kiel, Germany.
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13
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Hrubý J, Dvořák D, Squillantini L, Mannini M, van Slageren J, Herchel R, Nemec I, Neugebauer P. Co(II)-Based single-ion magnets with 1,1'-ferrocenediyl-bis(diphenylphosphine) metalloligands. Dalton Trans 2020; 49:11697-11707. [PMID: 32789384 DOI: 10.1039/d0dt01512a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Herein, we report on investigations of magnetic and spectroscopic properties of three heterobimetallic Fe(ii)-Co(ii) coordination compounds based on the tetracoordinate {CoP2X2} core encapsulated by dppf metalloligand, where X = Cl (1), Br (2), I (3), dppf = 1,1'-ferrocenediyl -bis(diphenylphosphine). The analysis of static magnetic data has revealed the presence of axial magnetic anisotropy in compounds (1) and (2) and this was further confirmed by high-frequency electron spin resonance (HF-ESR) spectroscopy. Dynamic magnetic data confirmed that (1) and (2) behave as field-induced Single-Ion Magnets (SIMs). Together with bulk studies, we have also tested the possibility of depositing (2) as thick films on Au(111), glass, and polymeric acetate by drop-casting as well as thermal sublimation, a key aspect for the development of future devices embedding these magnetic objects.
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Affiliation(s)
- J Hrubý
- Central European Institute of Technology, CEITEC BUT, Purkyňova 656/123, 61200 Brno, Czech Republic.
| | - D Dvořák
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 77147 Olomouc, Czech Republic
| | - L Squillantini
- Department of Chemistry "Ugo Schiff", University of Florence and INSTM Research Unit of Florence, via Lastruccia 3-13, 50019 Sesto Fiorentino, Italy
| | - M Mannini
- Department of Chemistry "Ugo Schiff", University of Florence and INSTM Research Unit of Florence, via Lastruccia 3-13, 50019 Sesto Fiorentino, Italy
| | - J van Slageren
- Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - R Herchel
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 77147 Olomouc, Czech Republic
| | - I Nemec
- Central European Institute of Technology, CEITEC BUT, Purkyňova 656/123, 61200 Brno, Czech Republic. and Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 77147 Olomouc, Czech Republic
| | - P Neugebauer
- Central European Institute of Technology, CEITEC BUT, Purkyňova 656/123, 61200 Brno, Czech Republic.
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14
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Peng G, Chen Y, Li B, Zhang YQ, Ren XM. Bulky Schiff-base ligand supported Co(ii) single-ion magnets with zero-field slow magnetic relaxation. Dalton Trans 2020; 49:5798-5802. [PMID: 32338258 DOI: 10.1039/d0dt00790k] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two mononuclear Co(ii) complexes with tetrahedral coordination geometry have been constructed from different bulky Schiff-base ligands. Both complexes exhibit slow magnetic relaxation without a static field and their relaxation behaviors can be tuned by ligand substitution. Clear magnetic hysteresis loops were observed for both complexes at 2 K.
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Affiliation(s)
- Guo Peng
- School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, P. R. China.
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15
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Rams M, Jochim A, Böhme M, Lohmiller T, Ceglarska M, Rams MM, Schnegg A, Plass W, Näther C. Single-Chain Magnet Based on Cobalt(II) Thiocyanate as XXZ Spin Chain. Chemistry 2020; 26:2837-2851. [PMID: 31702081 PMCID: PMC7078958 DOI: 10.1002/chem.201903924] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Indexed: 11/11/2022]
Abstract
The cobalt(II) in [Co(NCS)2 (4-methoxypyridine)2 ]n are linked by pairs of thiocyanate anions into linear chains. In contrast to a previous structure determination, two crystallographically independent cobalt(II) centers have been found to be present. In the antiferromagnetic state, below the critical temperature (Tc =3.94 K) and critical field (Hc =290 Oe), slow relaxations of the ferromagnetic chains are observed. They originate mainly from defects in the magnetic structure, which has been elucidated by micromagnetic Monte Carlo simulations and ac measurements using pristine and defect samples. The energy barriers of the relaxations are Δτ1 =44.9(5) K and Δτ2 =26.0(7) K for long and short spin chains, respectively. The spin excitation energy, measured by using frequency-domain EPR spectroscopy, is 19.1 cm-1 and shifts 0.1 cm-1 due to the magnetic ordering. Ab initio calculations revealed easy-axis anisotropy for both CoII centers, and also an exchange anisotropy Jxx /Jzz of 0.21. The XXZ anisotropic Heisenberg model (solved by using the density renormalization matrix group technique) was used to reconcile the specific heat, susceptibility, and EPR data.
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Affiliation(s)
- Michał Rams
- Institute of Physics, Jagiellonian University, Łojasiewicza 11, 30348, Kraków, Poland
| | - Aleksej Jochim
- Institut für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Straße 2, 24118, Kiel, Germany
| | - Michael Böhme
- Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstr. 8, 07743, Jena, Germany
| | - Thomas Lohmiller
- EPR4Energy Joint Lab, Institut für Nanospektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Kekuléstr. 5, 12489, Berlin, Germany
| | - Magdalena Ceglarska
- Institute of Physics, Jagiellonian University, Łojasiewicza 11, 30348, Kraków, Poland
| | - Marek M Rams
- Institute of Physics, Jagiellonian University, Łojasiewicza 11, 30348, Kraków, Poland
| | - Alexander Schnegg
- EPR4Energy Joint Lab, Institut für Nanospektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Kekuléstr. 5, 12489, Berlin, Germany.,EPR Research Group, MPI for Chemical Energy Conversion, Stiftstraße 34-36, 45470, Mülheim an der Ruhr, Germany
| | - Winfried Plass
- Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstr. 8, 07743, Jena, Germany
| | - Christian Näther
- Institut für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Straße 2, 24118, Kiel, Germany
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16
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Kowalkowska-Zedler D, Dołęga A, Nedelko N, Łyszczek R, Aleshkevych P, Demchenko I, Łuczak J, Slawska-Waniewska A, Pladzyk A. Structural, magnetic and spectral properties of tetrahedral cobalt(ii) silanethiolates: a variety of structures and manifestation of field-induced slow magnetic relaxation. Dalton Trans 2020; 49:697-710. [PMID: 31848544 DOI: 10.1039/c9dt03722e] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Blue crystals of five heteroleptic cobalt(ii) silanethiolates 1-5 have been obtained by the reaction of [Co{SSi(tBuO)3}2(NH3)]2 with aminopyridines and aminomethylpyridines at an appropriate molar ratio and their structural, spectral, thermal and magnetic properties have been established and described. All complexes 1-5 contain Co(ii) ions in a tetrahedral CoN2S2 environment formed by (tBuO)3SiS- residues and pyridines and present variable structures. Complexes 1-3 are mononuclear [Co{SSi(tBuO)3}2(L1)2] (L1 = 2-aminopyridine 2AP, 3-aminopyridine 3AP, and 4-aminopyridine 4AP). The application of 3AMP and 4AMP (3-aminomethylpyridine and 4-aminomethylpyridine) allows either dinuclear complex 4 [Co{SSi(tBuO)3}2(μ-3AMP)]2 or 1D coordination polymer 5 with the formula of [Co{SSi(tBuO)3}2(μ-4AMP)]n to be obtained. The molecular structures of 1-5 were determined by single-crystal X-ray and powder diffraction, UV-vis and FTIR spectrocopy for solid samples and their thermal properties were characterized by TG-DSC and TG-FTIR methods. The dc and ac magnetic and EPR studies of polycrystalline samples have been performed. For all complexes, the obtained data show a behavior typical of paramagnetic high-spin Co(ii) ions in a tetrahedral geometry, with a considerable contribution of the ZFS effect in a low temperature range. All complexes were also probed for SIM behavior. The modeling of the magnetic and EPR data was done for samples 1, 3, 4 and 5 to estimate ZFS parameters. The obtained results imply a negative value of the axial parameter D in complex 4 and positive D values for the rest of the compounds. A comparative magneto-structural analysis of complexes 4 and 5 points to the high sensitivity of the single-ion magnetic anisotropy of tetrahedral Co(ii) complexes to subtle changes in the first and second coordination spheres of Co(ii) ions.
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Affiliation(s)
- D Kowalkowska-Zedler
- Department of Inorganic Chemistry, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza Str. 11/12, 80-233 Gdańsk, Poland.
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17
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Zoufalý P, Čižmár E, Kuchár J, Herchel R. The Structural and Magnetic Properties of Fe II and Co II Complexes with 2-(furan-2-yl)-5-pyridin-2-yl-1,3,4-oxadiazole. Molecules 2020; 25:molecules25020277. [PMID: 31936620 PMCID: PMC7024161 DOI: 10.3390/molecules25020277] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/06/2020] [Accepted: 01/07/2020] [Indexed: 11/16/2022] Open
Abstract
Two novel coordination compounds containing heterocyclic bidentate N,N-donor ligand 2-(furan-2-yl)-5-(pyridin-2-yl)-1,3,4-oxadiazole (fpo) were synthesized. A general formula for compounds originating from perchlorates of iron, cobalt, and fpo can be written as: [M(fpo)2(H2O)2](ClO4)2 (M = Fe(II) for (1) Co(II) for (2)). The characterization of compounds was performed by general physico-chemical methods-elemental analysis (EA), Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) in case of organics, and single crystal X-ray diffraction (sXRD). Moreover, magneto-chemical properties were studied employing measurements in static field (DC) for 1 and X-band EPR (Electron paramagnetic resonance), direct current (DC), and alternating current (AC) magnetic measurements in case of 2. The analysis of DC magnetic properties revealed a high spin arrangement in 1, significant rhombicity for both complexes, and large magnetic anisotropy in 2 (D = -21.2 cm-1). Moreover, 2 showed field-induced slow relaxation of the magnetization (Ueff = 65.3 K). EPR spectroscopy and ab initio calculations (CASSCF/NEVPT2) confirmed the presence of easy axis anisotropy and the importance of the second coordination sphere.
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Affiliation(s)
- Pavel Zoufalý
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. Listopadu 12, CZ-771 46 Olomouc, Czech Republic; (P.Z.); or
| | - Erik Čižmár
- Institute of Physics, Faculty of Science, P.J. Šafárik University in Košice, Park Angelinum 9, SK-041 54 Košice, Slovakia;
| | - Juraj Kuchár
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. Listopadu 12, CZ-771 46 Olomouc, Czech Republic; (P.Z.); or
- Department of Inorganic Chemistry, Institute of Chemistry, Faculty of Science, P.J. Šafárik University in Košice, Moyzesova 11, SK-041 54 Košice, Slovakia
| | - Radovan Herchel
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. Listopadu 12, CZ-771 46 Olomouc, Czech Republic; (P.Z.); or
- Correspondence: ; Tel.: +420-58563-4435
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18
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Kowalkowska-Zedler D, Nedelko N, Kazimierczuk K, Aleshkevych P, Łyszczek R, Ślawska-Waniewska A, Pladzyk A. Novel tetrahedral cobalt( ii) silanethiolates: structures and magnetism. RSC Adv 2020; 10:29100-29108. [PMID: 35521135 PMCID: PMC9055939 DOI: 10.1039/d0ra06036d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 07/31/2020] [Indexed: 11/23/2022] Open
Abstract
Three heteroleptic complexes of Co(ii) tri-tert-butoxysilanethiolates have been synthesized with piperidine [Co{SSi(OtBu)3}2(ppd)2] 1, piperazine [Co{SSi(OtBu)3}2(NH3)]2(μ-ppz)·2CH3CN 2, and N-ethylimidazole [Co{SSi(OtBu)3}2(etim)2] 3. The complexes have been characterized by a single-crystal X-ray, revealing their tetrahedral geometry on Co(ii) coordinated by two nitrogen and two sulfur atoms. Complexes 1 and 3 are mononuclear, whereas 2 is binuclear. The spectral properties and thermal properties of 1–3 complexes were established by FTIR spectroscopy for solid samples and TGA. The magnetic properties of complexes 1, 2, and 3 have been investigated by static magnetic measurements and X-band EPR spectroscopy. These studies have shown that 1 and 3, regardless of the similarity in structure of CoN2S2 cores, demonstrate different types of local magnetic anisotropy. Magnetic investigations of 2 reveal the presence of weak antiferromagnetic intra-molecular Co(ii)–Co(ii) interactions that are strongly influenced by the local magnetic anisotropy of individual Co(ii) ions. Structural, spectral and thermal properties of three tetrahedral Co(ii) silanethiolates were established by XRD, FTIR for solid samples and TGA. The magnetic properties were investigated by static magnetic measurements and X-band EPR spectroscopy.![]()
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Affiliation(s)
- Daria Kowalkowska-Zedler
- Department of Inorganic Chemistry
- Faculty of Chemistry
- Gdańsk University of Technology
- 80-233 Gdańsk
- Poland
| | - Natalia Nedelko
- Institute of Physics
- Polish Academy of Sciences
- 02-668 Warsaw
- Poland
| | - Katarzyna Kazimierczuk
- Department of Inorganic Chemistry
- Faculty of Chemistry
- Gdańsk University of Technology
- 80-233 Gdańsk
- Poland
| | | | - Renata Łyszczek
- Department of Coordination and General Chemistry and Crystallography
- Institute of Chemical Sciences
- Faculty of Chemistry
- Maria Curie-Skłodowska University in Lublin
- 20-031 Lublin
| | | | - Agnieszka Pladzyk
- Department of Inorganic Chemistry
- Faculty of Chemistry
- Gdańsk University of Technology
- 80-233 Gdańsk
- Poland
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19
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Massoud SS, Perez ZE, Courson JR, Fischer RC, Mautner FA, Vančo J, Čajan M, Trávníček Z. Slow magnetic relaxation in penta-coordinate cobalt(ii) field-induced single-ion magnets (SIMs) with easy-axis magnetic anisotropy. Dalton Trans 2020; 49:11715-11726. [DOI: 10.1039/d0dt02338h] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two penta-coordinate [Co(Ln)(NCS)]ClO4 with substituted pyridyl based bispyrazolyl ligands have been structurally characterized. The complexes show an easy-axis magnetic anisotropy, large rhombicity and slow relaxation of magnetization.
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Affiliation(s)
- Salah S. Massoud
- Department of Chemistry
- University of Louisiana at Lafayette
- Lafayette
- USA
- Department of Chemistry
| | - Zoe E. Perez
- Department of Chemistry
- University of Louisiana at Lafayette
- Lafayette
- USA
| | | | - Roland C. Fischer
- Institut für Anorganische Chemie
- Technische Universität Graz
- A-8010 Graz
- Austria
| | - Franz A. Mautner
- Institut für Physikalische and Theoretische Chemie
- Technische Universität Graz
- A-8010 Graz
- Austria
| | - Ján Vančo
- Regional Centre of Advanced Technologies and Materials
- Division of Biologically Active Complexes and Molecular Magnets
- Palacký University in Olomouc
- CZ-783 71 Olomouc
- Czech Republic
| | - Michal Čajan
- Regional Centre of Advanced Technologies and Materials
- Division of Biologically Active Complexes and Molecular Magnets
- Palacký University in Olomouc
- CZ-783 71 Olomouc
- Czech Republic
| | - Zdeněk Trávníček
- Regional Centre of Advanced Technologies and Materials
- Division of Biologically Active Complexes and Molecular Magnets
- Palacký University in Olomouc
- CZ-783 71 Olomouc
- Czech Republic
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20
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Böhme M, Plass W. How to link theory and experiment for single-chain magnets beyond the Ising model: magnetic properties modeled from ab initio calculations of molecular fragments. Chem Sci 2019; 10:9189-9202. [PMID: 32055306 PMCID: PMC6979495 DOI: 10.1039/c9sc02735a] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 08/15/2019] [Indexed: 12/23/2022] Open
Abstract
Magnetic properties of coordination polymers like single-chain magnets (SCMs) are based on magnetic domains, which are formed due to magnetic exchange between neighboring anisotropic spin centers. However, the computational restrictions imposed by the high level of theory needed for an adequate ab initio quantum mechanical treatment on the basis of multi-reference methods for these systems limit the feasibility of such calculations to mononuclear fragments as appropriate structural cutouts for the metal centers along the chains. Hence, results from such calculations describe single-ion properties and cannot be directly correlated with experimental data representing magnetic domains. We present a theoretical approach based on n-membered Ising-spin rings with n = 3-12, which allows us to simulate magnetic domains and to derive important magnetic properties for SCM compounds. Magnetic exchange, which is not provided by calculations of mononuclear fragments, is obtained by fitting the theoretical magnetic susceptibility against experimental data. The presented approach is tested for cobalt(ii)-based SCMs with three types of repeating sequences, which differ in nuclearity and symmetry. The magnetic parameters derived using the presented approach were found to be in good agreement with the experimental data. Moreover, the energy spectra obtained for the three test cases using the presented approach are characteristic of a deviation of the individual systems from the ideal Ising behavior. An extrapolation technique towards larger systems (n > 12) is presented which can provide information on the statistical mean length of the magnetic domains in the three investigated SCM compounds.
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Affiliation(s)
- Michael Böhme
- Institut für Anorganische und Analytische Chemie , Friedrich-Schiller-Universität Jena , Humboldtstraße 8 , 07743 Jena , Germany . ; ; Tel: +49 3641 948130
| | - Winfried Plass
- Institut für Anorganische und Analytische Chemie , Friedrich-Schiller-Universität Jena , Humboldtstraße 8 , 07743 Jena , Germany . ; ; Tel: +49 3641 948130
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21
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Cui Y, Ge Y, Li Y, Tao J, Yao J, Dong Y. Single-ion magnet behavior of two pentacoordinate CoII complexes with a pincer ligand 2,6-bis(imidazo[1,5-a] pyridin-3-yl)pyridine. Struct Chem 2019. [DOI: 10.1007/s11224-019-01429-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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22
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Cui Y, Xu Y, Liu X, Li Y, Wang BL, Dong Y, Li W, Lei S. Field-Induced Single-Ion Magnetic Behavior in Two Mononuclear Cobalt(II) Complexes. Chem Asian J 2019; 14:2620-2628. [PMID: 31066179 DOI: 10.1002/asia.201900258] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 04/30/2019] [Indexed: 11/08/2022]
Abstract
The employment of a new rigid N-tridentate ligand, bis(1-chloroimidazo[1,5-a]pyridin-3-yl)pyridine (bcpp), in the construction of cobalt(II) single-ion magnets is reported. Two cobalt(II) complexes, [Co(bcpp)Cl2 ] (1) and [Co(bcpp)Br2 ] (2), have been prepared and characterized. Single-crystal XRD analyses reveal that complexes 1 and 2 are isostructural. They are pentacoordinated mononuclear cobalt(II) compounds with expected trigonal bipyramidal geometry. Both analysis of the magnetic data and ab initio calculations reveal easy-plane magnetic anisotropy (D>0) for 1 and 2. Detailed alternating current magnetic susceptibility measurements reveal the occurrence of slow magnetic relaxation behavior for the cobalt(II) centers of 1 and 2; thus indicating that both complexes are field-induced single-ion magnets.
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Affiliation(s)
- Yanfeng Cui
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, P.R. China.,Key Laboratory of Salt Lake Resources and Chemistry, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, 810008, P.R. China
| | - Yameng Xu
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, P.R. China
| | - Xin Liu
- Key Laboratory of Salt Lake Resources and Chemistry, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, 810008, P.R. China
| | - Yahong Li
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, P.R. China
| | - Bao-Lin Wang
- Jiangsu Key Laboratory for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing, 210023, P.R. China
| | - Yaping Dong
- Key Laboratory of Salt Lake Resources and Chemistry, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, 810008, P.R. China
| | - Wu Li
- Key Laboratory of Salt Lake Resources and Chemistry, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, 810008, P.R. China
| | - Shiming Lei
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA
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23
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Kintzel B, Böhme M, Liu J, Burkhardt A, Mrozek J, Buchholz A, Ardavan A, Plass W. Molecular electronic spin qubits from a spin-frustrated trinuclear copper complex. Chem Commun (Camb) 2018; 54:12934-12937. [PMID: 30302454 DOI: 10.1039/c8cc06741d] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The trinuclear copper(ii) complex [Cu3(saltag)(py)6]ClO4 (H5saltag = tris(2-hydroxybenzylidene)triaminoguanidine) was synthesized and characterized by experimental as well as theoretical methods. This complex exhibits a strong antiferromagnetic coupling (J = -298 cm-1) between the copper(ii) ions, mediated by the N-N diazine bridges of the tritopic ligand, leading to a spin-frustrated system. This compound shows a T2 coherence time of 340 ns in frozen pyridine solution, which extends to 591 ns by changing the solvent to pyridine-d5. Hence, the presented compound is a promising candidate as a building block for molecular spintronics.
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Affiliation(s)
- Benjamin Kintzel
- Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstraße 8, 07745 Jena, Germany.
| | - Michael Böhme
- Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstraße 8, 07745 Jena, Germany.
| | - Junjie Liu
- The Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Anja Burkhardt
- Photon Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Jakub Mrozek
- The Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Axel Buchholz
- Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstraße 8, 07745 Jena, Germany.
| | - Arzhang Ardavan
- The Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Winfried Plass
- Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldtstraße 8, 07745 Jena, Germany.
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