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Wang M, Han Z, Garcia Y, Cheng P. Six-Coordinated Co II Single-Molecule Magnets: Synthetic Strategy, Structure and Magnetic Properties. Chemphyschem 2024; 25:e202400396. [PMID: 38889310 DOI: 10.1002/cphc.202400396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Revised: 06/15/2024] [Accepted: 06/17/2024] [Indexed: 06/20/2024]
Abstract
The pursuit of molecule-based magnetic memory materials contributes significantly to high-density information storage research in the frame of the ongoing information technologies revolution. Remarkable progress has been achieved in both transition metal (TM) and lanthanide based single-molecule magnets (SMMs). Notably, six-coordinated CoII SMMs hold particular research significance owing to the economic and abundant nature of 3d TM ions compared to lanthanide ions, the substantial spin-orbit coupling of CoII ions, the potential for precise control over coordination geometry, and the air-stability of coordination-saturated structures. In this review, we will summarize the progress made in six-coordinated CoII SMMs, organized by their coordination geometry and molecular structure similarity. Valuable insights, principles, and new mechanism gleaned from this research and remaining issues that need to be addressed will also be discussed to guide future optimization.
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Affiliation(s)
- Mengmeng Wang
- Institute of Condensed Matter and Nanosciences, Molecular Chemistry, Materials and Catalysis (IMCN/MOST), Université catholique de Louvain, 1348, Louvain-la-Neuve, Belgium
- Key Laboratory of Advanced Energy Materials Chemistry (MOE) and Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Zongsu Han
- Key Laboratory of Advanced Energy Materials Chemistry (MOE) and Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin, 300071, China
- Department of Chemistry, Texas A&M University, College Station, Texas, 77843, United States
| | - Yann Garcia
- Institute of Condensed Matter and Nanosciences, Molecular Chemistry, Materials and Catalysis (IMCN/MOST), Université catholique de Louvain, 1348, Louvain-la-Neuve, Belgium
| | - Peng Cheng
- Key Laboratory of Advanced Energy Materials Chemistry (MOE) and Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin, 300071, China
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2
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Biswas S, Havlicek L, Nemec I, Salitros I, Mandal L, Neugebauer P, Kuppusamy SK, Ruben M. Levamisole Based Co(II) Single-Ion Magnet. Chem Asian J 2024; 19:e202400574. [PMID: 38870468 DOI: 10.1002/asia.202400574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2024] [Revised: 06/13/2024] [Accepted: 06/13/2024] [Indexed: 06/15/2024]
Abstract
A new Co(II) complex, [Co(NCS)2(L)2] (1) has been synthesized based on levamisole (L) as a new ligand. Single-crystal X-ray diffraction analyses confirm that the Co(II) ion is having a distorted tetrahedral coordination geometry in the complex. Notably strong intramolecular S⋅⋅⋅S and S⋅⋅⋅N interactions has been confirmed by employing Quantum Theory of Atoms in Molecules (QTAIM). These intramolecular interactions occur among the sulfur and nitrogen atoms of the levamisole ligands and also the nitrogen atoms of the thiocyanate. Direct current (dc) magnetic analyses reveal presence of zero field splitting (ZFS) and large magnetic anisotropy on Co(II). Detailed ab initio ligand field theory calculations quantitatively predicted the magnitude of ZFS. Prominent field-induced single-ion magnet (SIM) behavior was observed for 1 from dynamic magnetization measurements. Slow magnetic relaxation follows an Orbach mechanism with the effective energy barrier Ueff=29.6 (7) K and relaxation time τo=1.4 (4)×10-9 s.
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Affiliation(s)
- Soumava Biswas
- Dr. Vishwanath Karad MIT World Peace University Survey No, 124, Paud Rd, Kothrud, Pune, 411038, Maharashtra, India
| | - Lubomir Havlicek
- Central European Institute of Technology, Brno University of Technology, Purkynova 656/123, 61200, Brno, Czech Republic
- Institute of Physics of Materials, Czech Academy of Sciences, Zizkova 22, 61662, Brno, Czech Republic
| | - Ivan Nemec
- Central European Institute of Technology, Brno University of Technology, Purkynova 656/123, 61200, Brno, Czech Republic
- Department of Inorganic Chemistry, Faculty of Science, Palacky University, 17. listopadu 12, 77147, Olomouc, Czech Republic
| | - Ivan Salitros
- Central European Institute of Technology, Brno University of Technology, Purkynova 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
| | - Leena Mandal
- Department of Chemistry, Polba Mahavidyalaya, Polba Hooghly, PIN-712148, West Bengal, India
| | - Petr Neugebauer
- Central European Institute of Technology, Brno University of Technology, Purkynova 656/123, 61200, Brno, Czech Republic
| | - Senthil Kumar Kuppusamy
- Institute of Quantum Materials and Technologies (IQMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Mario Ruben
- Institute of Quantum Materials and Technologies (IQMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz1, 76344, Eggenstein-Leopoldshafen, Germany
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Zahradníková E, Pichon C, Duhayon C, Sutter JP, Halaš P, Drahoš B. Synthesis, structural and magnetic properties of cobalt(ii) complexes with pyridine-based macrocyclic ligand containing two pyridine pendant arms. RSC Adv 2024; 14:28138-28147. [PMID: 39228762 PMCID: PMC11369886 DOI: 10.1039/d4ra02387k] [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: 03/28/2024] [Accepted: 08/13/2024] [Indexed: 09/05/2024] Open
Abstract
With the aim of tuning the magnetic anisotropy, a series of Co(ii) complexes with the general formula of complex cations [Co(L)X]+, where X = Br- (1); I- (2); NCO- (3); NCS- (4a); N3 - (5), and [Co(L)(NCS)2] (4b), (L = a 17-membered pyridine-based N3O2-macrocyclic ligand containing two pyridin-2-ylmethyl pendant arms) were prepared and thoroughly characterized. The molecular structures for all complexes showed strongly distorted geometry in between octahedral and trigonal prismatic. The magnetic studies confirmed substantial magnetic anisotropy with positive values of D, the axial zero-field splitting parameter, but E/D ratios close to 1/3. This was supported by theoretical CASSCF calculations showing no significant effect of the co-ligands. Complex 4b was found to behave as a field-induced SMM.
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Affiliation(s)
- Eva Zahradníková
- Department of Inorganic Chemistry, Faculty of Science, Palacký University Olomouc 17. listopadu 12 CZ-771 46 Olomouc Czech Republic +420 585 634 954 +420 585 634 429
| | - Céline Pichon
- Laboratoire de Chimie de Coordination du CNRS (LCC-CNRS), Université de Toulouse, CNRS Toulouse France
| | - Carine Duhayon
- Laboratoire de Chimie de Coordination du CNRS (LCC-CNRS), Université de Toulouse, CNRS Toulouse France
| | - Jean-Pascal Sutter
- Laboratoire de Chimie de Coordination du CNRS (LCC-CNRS), Université de Toulouse, CNRS Toulouse France
| | - Petr Halaš
- Department of Inorganic Chemistry, Faculty of Science, Palacký University Olomouc 17. listopadu 12 CZ-771 46 Olomouc Czech Republic +420 585 634 954 +420 585 634 429
| | - Bohuslav Drahoš
- Department of Inorganic Chemistry, Faculty of Science, Palacký University Olomouc 17. listopadu 12 CZ-771 46 Olomouc Czech Republic +420 585 634 954 +420 585 634 429
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Landart A, Quesada-Moreno MM, Palacios MA, Li Y, Ozerov M, Krzystek J, Colacio E. Control of the geometry and anisotropy driven by the combination of steric and anion coordination effects in Co II complexes with N 6-tripodal ligands: the impact of the size of the ligand on the magnetization relaxation time. Dalton Trans 2024; 53:12876-12892. [PMID: 38716508 DOI: 10.1039/d4dt00622d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/07/2024]
Abstract
Four mononuclear CoII complexes of formula [Co(L)(SCN)2(CH3OH)0.5(H2O)0.5]·1.5H2O·0.75CH3OH (1), [Co(L1)Cl2]·H2O·2CH3CN (2), [Co(L1)(SCN)2]·1.5H2O·CH3OH (3) and [Co(L1)]ClO4·2CH3OH (4) were prepared from the N6-tripodal Schiff base ligands (S)P[N(Me)NC(H)2-Q]3 (L) and (S)P[N(Me)NC(H)1-ISOQ]3 (L1), where Q and ISOQ represent quinolyl and isoquinolyl moieties, respectively. In 1, the L ligand does not coordinate to the CoII ion in a tripodal manner but using a new N,N,S tridentate mode, which is due to the fact that the N6-tripodal coordination promotes a strong steric hindrance between the quinolyl moieties. However, L1 can coordinate to the CoII ions either in a tripodal manner using CoII salts with poorly coordinating anions to give 4 or in a bisbidentate fashion using CoII salt-containing medium to strongly coordinating anions to afford 2 and 3. In the case of L1, there is no steric hindrance between ISOQ moieties after coordination to the CoII ion. The CoII ion exhibits a distorted octahedral geometry for compounds 1-3, with the anions in cis positions for the former and in trans positions for the two latter compounds. Compound 4 shows an intermediate geometry between an octahedral and trigonal prism but closer to the latter one. DC magnetic properties, HFEPR and FIRMS measurements and ab initio calculations demonstrate that distorted octahedral complexes 1-3 exhibit easy-plane magnetic anisotropy (D > 0), whereas compound 4 shows large easy-axis magnetic anisotropy (D < 0). Comparative analysis of the magneto-structural data underlines the important role that is played not only by the coordination geometry but also the electronic effects in determining the anisotropy of the CoII ions. Compounds 2-3 show a field-induced slow relaxation of magnetization. Despite its large easy-axis magnetic anisotropy, compound 4 does not show significant slow relaxation (SMR) above 2 K under zero applied magnetic fields, but its magnetic dilution with ZnII triggers SMR at zero field. Finally, it is worth remarking that compounds 2-4 show smaller relaxation times than the analogous complexes with the tripodal ligand bearing in its arms pyridine instead of isoquinoline moieties, which is most likely due to the increase of the molecular size in the former one.
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Affiliation(s)
- Aritz Landart
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain.
| | - María Mar Quesada-Moreno
- Departamento de Química Física y Analítica, Facultad de Ciencias Experimentales, Universidad de Jaén, Campus Las Lagunillas, 23071 Jaén, Spain
| | - María A Palacios
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain.
| | - Yanling Li
- Sorbonne Université Institut Parisien de Chimie Moléculaire, CNRS UMR 8232 4 place Jussieu 75252, Paris cedex 5, France
| | - Mykhaylo Ozerov
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - J Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - Enrique Colacio
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain.
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Juráková J, Santana VT, Pavlik J, Moncoľ J, Nemec I, Clemente-León M, Kuppusamy SK, Ruben M, Čižmár E, Šalitroš I. Magnetic anisotropy and slow relaxation of magnetisation in double salts containing four- and six-coordinate cobalt(II) complex ions. Dalton Trans 2024; 53:12962-12972. [PMID: 39026489 DOI: 10.1039/d4dt01509f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Four novel Co(II) coordination compounds 1-4 of the general formula [Co(Ln)2][Co(NCY)4]·mCH3CN (where Ln are tridentate ligands L1 = 2,6-bis(1-hexyl-1H-benzimidazol-2-yl)pyridine for 1 and 2; L2 = 2,6-bis(1-octyl-1H-benzimidazol-2-yl)pyridine for 3; L3 = 2,6-bis(1-dodecyl-1H-benzimidazol-2-yl)pyridine for 4, Y = O for 1, 3, and 4 and Y = S for 2; m = 0 for 1 and 3, m = 0.5 for 2 and m = 2 for 4) were prepared and characterised. The molecular structures of all four compounds consist of the hexacoordinate complex cation [Co(Ln)2]2+ and tetracoordinate complex anion [Co(NCY)4]2-, with distorted octahedral and tetrahedral symmetry of coordination polyhedra, respectively. The electronic structures of all compounds feature an orbitally non-degenerate ground state well-separated from the lowest excited state, which allows the analysis of the magnetic anisotropy by the spin Hamiltonian model. ZFS parameters, derived from both CASSCF-NEVPT2 calculations and magnetic data analysis, indicate that tetrahedral anions [Co(NCY)4]2- exhibit small axial parameters |D| spanning the range of 2.2 to 7.7 cm-1, while octahedral cations [Co(Ln)2]2+ display significantly larger |D| parameters in the range of 37 to 95 cm-1. For 1-3, the Fourier-transform infrared magnetic spectroscopy (FIRMS) revealed a reasonable transmission with a magnetic absorption around the expected value for the ZFS accompanied by features allowing to identify phonon frequencies and simulate spin-phonon couplings. Dynamic magnetic investigations unveiled the field-induced slow relaxation of magnetisation, with maximal relaxation times (τ) of 92(2) μs for 2 at 2 K and BDC = 0.3 T. The temperature evolution of τ was analysed using a combination of Orbach, direct and Raman relaxations (Ueff = 8(1) K (5.6 cm-1)) or Orbach, direct and spin-phonon induced relaxations (Ueff = 10.3(9) K (7.2 cm-1)). The rest of the complexes, namely 1, 3, and 4 show field-induced slow relaxation of magnetisation with τ smaller than 16 μs.
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Affiliation(s)
- Jana Juráková
- Central European Institute of Technology, Brno University of Technology, Purkyňova 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 Tadeu Santana
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 61200 Brno, Czech Republic
| | - Ján Pavlik
- Department of Inorganic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Bratislava SK-81237, Slovakia.
| | - Ján Moncoľ
- Department of Inorganic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Bratislava SK-81237, Slovakia.
| | - Ivan Nemec
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 61200 Brno, Czech Republic
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 771 46 Olomouc, Czech Republic
| | - Miguel Clemente-León
- Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, Catedrático José Beltrán 2, 46980 Paterna, Spain
| | - Senthil Kumar Kuppusamy
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Mario Ruben
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Erik Čižmár
- Institute of Physics, Faculty of Science, P.J. Šafárik University, Park Angelinum 9, 04154 Košice, Slovakia
| | - Ivan Šalitroš
- Central European Institute of Technology, Brno University of Technology, Purkyňova 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.
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6
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Hand AT, Watson-Sanders BD, Xue ZL. Spectroscopic techniques to probe magnetic anisotropy and spin-phonon coupling in metal complexes. Dalton Trans 2024; 53:4390-4405. [PMID: 38380640 DOI: 10.1039/d3dt03609j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Magnetism of molecular quantum materials such as single-molecule magnets (SMMs) has been actively studied for potential applications in the new generation of high-density data storage using SMMs and quantum information science. Magnetic anisotropy and spin-phonon coupling are two key properties of d- and f-metal complexes. Here, phonons refer to both intermolecular and intramolecular vibrations. Direct determination of magnetic anisotropy and experimental studies of spin-phonon coupling are critical to the understanding of molecular magnetism. This article discusses our recent approach in using three complementary techniques, far-IR and Raman magneto-spectroscopies (FIRMS and RaMS, respectively) and inelastic neutron scatterings (INS), to determine magnetic excited states. Spin-phonon couplings are observed in FIRMS and RaMS. DFT phonon calculations give energies and symmetries of phonons as well as calculated INS spectra which help identify magnetic peaks in experimental INS spectra.
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Affiliation(s)
- Adam T Hand
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA.
| | | | - Zi-Ling Xue
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA.
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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.
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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
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Zabala-Lekuona A, Landart-Gereka A, Quesada-Moreno MM, Mota AJ, Díaz-Ortega IF, Nojiri H, Krzystek J, Seco JM, Colacio E. Zero-Field SMM Behavior Triggered by Magnetic Exchange Interactions and a Collinear Arrangement of Local Anisotropy Axes in a Linear Co 3II Complex. Inorg Chem 2023. [PMID: 37991724 DOI: 10.1021/acs.inorgchem.3c02817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
A new linear trinuclear Co(II)3 complex with a formula of [{Co(μ-L)}2Co] has been prepared by self-assembly of Co(II) ions and the N3O3-tripodal Schiff base ligand H3L, which is obtained from the condensation of 1,1,1-tris(aminomethyl)ethane and salicylaldehyde. Single X-ray diffraction shows that this compound is centrosymmetric with triple-phenolate bridging groups connecting neighboring Co(II) ions, leading to a paddle-wheel-like structure with a pseudo-C3 axis lying in the Co-Co-Co direction. The Co(II) ions at both ends of the Co(II)3 molecule exhibit distorted trigonal prismatic CoN3O3 geometry, whereas the Co(II) at the middle presents an elongated trigonal antiprismatic CoO6 geometry. The combined analysis of the magnetic data and theoretical calculations reveal strong easy-axis magnetic anisotropy for both types of Co(II) ions (|D| values higher than 115 cm-1) with the local anisotropic axes lying on the pseudo-C3 axis of the molecule. The magnetic exchange interaction between the middle and ends Co(II) ions, extracted by using either a Hamiltonian accounting for the isotropic magnetic coupling and ZFS or the Lines' model, was found to be medium to strong and antiferromagnetic in nature, whereas the interaction between the external Co(II) ions is weak antiferromagnetic. Interestingly, the compound exhibits slow relaxation of magnetization and open hysteresis at zero field and therefore SMM behavior. The significant magnetic exchange coupling found for [{Co(μ-L)}2Co] is mainly responsible for the quenching of QTM, which combined with the easy-axis local anisotropy of the CoII ions and the collinearity of their local anisotropy axes with the pseudo-C3 axis favors the observation of SMM behavior at zero field.
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Affiliation(s)
- Andoni Zabala-Lekuona
- Departamento de Química Aplicada, Facultad de Química, Universidad del País Vasco (UPV/EHU), 20018 Donostia-San Sebastián, Spain
| | - Aritz Landart-Gereka
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain
| | - María Mar Quesada-Moreno
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain
| | - Antonio J Mota
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain
| | - Ismael F Díaz-Ortega
- Institute for Materials Research, Tohoku University, Katahira, Sendai 980-8577, Japan
| | - Hiroyuki Nojiri
- Institute for Materials Research, Tohoku University, Katahira, Sendai 980-8577, Japan
| | - Jurek Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - José M Seco
- Departamento de Química Aplicada, Facultad de Química, Universidad del País Vasco (UPV/EHU), 20018 Donostia-San Sebastián, Spain
| | - Enrique Colacio
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain
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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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Dey A, Ali J, Moorthy S, Gonzalez JF, Pointillart F, Singh SK, Chandrasekhar V. Field induced single ion magnet behavior in Co II complexes in a distorted square pyramidal geometry. Dalton Trans 2023; 52:14807-14821. [PMID: 37791680 DOI: 10.1039/d3dt01769a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
We report three CoII-based complexes with the general formula [CoII(L)(X)2] by changing the halide/pseudo-halide ions [X = NCSe (1SeCN); Cl (2Cl) and Br (3Br)]. The obtained τ5 and CShM values confirm a distorted square pyramidal geometry around the CoII ion in all these complexes. In these three complexes, the central CoII ion is situated above the basal plane of the square pyramidal geometry. The extent of distortion from the ideal SPY-5 geometry differs upon changing the coordinating halide/pseudo-halide ion in these complexes. This essentially results in the alteration of the anisotropic parameter D and hence impacts the magnetic properties in these complexes. This phenomenon has been corroborated with the aid of theoretical investigations. All these complexes display field-induced SIM behaviour with magnetic relaxation occurring through a combination of processes depending on the applied dc magnetic field values and dilution.
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Affiliation(s)
- Atanu Dey
- Department of Chemistry, Gandhi Institute of Technology and Management (GITAM), NH 207, Nagadenehalli, Doddaballapur Taluk, Bengaluru 561203, India.
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad, 500 046, India.
| | - Junaid Ali
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad, 500 046, India.
| | - Shruti Moorthy
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, 502285, Telangana, India.
| | - Jessica Flores Gonzalez
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, 35000 Rennes, France.
| | - Fabrice Pointillart
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, 35000 Rennes, France.
| | - Saurabh Kumar Singh
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, 502285, Telangana, India.
| | - Vadapalli Chandrasekhar
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad, 500 046, India.
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
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Interplay of Anisotropic Exchange Interactions and Single-Ion Anisotropy in Single-Chain Magnets Built from Ru/Os Cyanidometallates(III) and Mn(III) Complex. Molecules 2023; 28:molecules28031516. [PMID: 36771182 PMCID: PMC9921754 DOI: 10.3390/molecules28031516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 01/26/2023] [Accepted: 01/27/2023] [Indexed: 02/08/2023] Open
Abstract
Two novel 1D heterobimetallic compounds {[MnIII(SB2+)MIII(CN)6]·4H2O}n (SB2+ = N,N'-ethylenebis(5-trimethylammoniomethylsalicylideneiminate) based on orbitally degenerate cyanidometallates [OsIII(CN)6]3- (1) and [RuIII(CN)6]3- (2) and MnIII Schiff base complex were synthesized and characterized structurally and magnetically. Their crystal structures consist of electrically neutral, well-isolated chains composed of alternating [MIII(CN)6]3- anions and square planar [MnIII(SB2+)]3+ cations bridged by cyanide groups. These -ion magnetic anisotropy of MnIII centers. These results indicate that the presence of compounds exhibit single-chain magnet (SCM) behavior with the energy barriers of Δτ1/kB = 73 K, Δτ2/kB = 41.5 K (1) and Δτ1/kB = 51 K, Δτ2 = 27 K (2). Blocking temperatures of TB = 2.8, 2.1 K and magnetic hysteresis with coercive fields (at 1.8 K) of 8000, 1600 Oe were found for 1 and 2, respectively. Theoretical analysis of the magnetic data reveals that their single-chain magnet behavior is a product of a complicated interplay of extremely anisotropic triaxial exchange interactions in MIII(4d/5d)-CN-MnIII fragments: -JxSMxSMnx-JySMySMny-JzSMzSMnz, with opposite sign of exchange parameters Jx = -22, Jy = +28, Jz = -26 cm-1 and Jx = -18, Jy = +20, Jz = -18 cm-1 in 1 and 2, respectively) and single orbitally degenerate [OsIII(CN)6]3- and [RuIII(CN)6]3- spin units with unquenched orbital angular momentum in the chain compounds 1 and 2 leads to a peculiar regime of slow magnetic relaxation, which is beyond the scope of the conventional Glaubers's 1D Ising model and anisotropic Heisenberg model.
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Aerogel-Based Single-Ion Magnets: A Case Study of a Cobalt(II) Complex Immobilized in Silica. MOLECULES (BASEL, SWITZERLAND) 2023; 28:molecules28010418. [PMID: 36615607 PMCID: PMC9824035 DOI: 10.3390/molecules28010418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/15/2022] [Accepted: 12/27/2022] [Indexed: 01/05/2023]
Abstract
The chemical immobilization of cobalt(II) ions in a silica aerogel matrix enabled the synthesis of the first representative example of aerogel-based single-ion magnets. For the synthesis of the lyogels, methyl-trimethoxysilane and N-3-(trimethoxysilyl)propyl ethylenediamine were co-hydrolyzed, then the ethylenediamine groups that were immobilized on the silica matrix enabled the subsequent binding of cobalt(II) ions. Lyogels with various amounts of ethylenediamine moieties (0.1-15 mol %) were soaked in isopropanol solutions of cobalt(II) nitrate and further supercritically dried in carbon dioxide to obtain aerogels with a specific surface area of 210-596 m2·g-1, an apparent density of 0.403-0.740 cm3·g-1 and a porosity of 60-78%. The actual cobalt content in the aerogels was 0.01-1.50 mmol per 1 g of SiO2, which could easily be tuned by the concentration of ethylenediamine moieties in the silica matrix. The introduction of cobalt(II) ions into the ethylenediamine-modified silica aerogel promoted the stability of the diamine moieties at the supercritical drying stage. The molecular prototype of the immobilized cobalt(II) complex, bearing one ethylenediamine ligand [Co(en)(MeCN)(NO3)2], was synthesized and structurally characterized. Using magnetometry in the DC mode, it was shown that cobalt(II)-modified silica aerogels exhibited slow magnetic relaxation in a nonzero field. A decrease in cobalt(II) concentration in aerogels from 1.5 mmol to 0.14 mmol per 1 g of SiO2 resulted in a weakening of inter-ion interactions; the magnetization reversal energy barrier likewise increased from 4 to 18 K.
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The Role of the Bridge in Single-Ion Magnet Behaviour: Reinvestigation of Cobalt(II) Succinate and Fumarate Coordination Polymers with Nicotinamide. INORGANICS 2022. [DOI: 10.3390/inorganics10090128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Two previously synthesized cobalt(II) coordination polymers; {[Co(μ2-suc)(nia)2(H2O)2]·2H2O}n (suc = succinate(2−), nia = nicotinamide) and [Co(μ2-fum)(nia)2(H2O)2]n (fum = fumarate(2−)) were prepared and thoroughly characterized. Both complexes form 1D coordination chains by bonding of Co(nia)2(H2O)2 units through succinate or fumarate ligands while these chains are further linked through hydrogen bonds to 3D supramolecular networks. The intermolecular interactions of both complexes are quantified using Hirshfeld surface analysis and their infrared spectra, electronic spectra and static magnetic properties are confronted with DFT and state-of-the-art ab-initio calculations. Dynamic magnetic measurements show that both complexes exhibit single-ion magnet behaviour induced by a magnetic field. Since they possess very similar chemical structure, differing only in the rigidity of the bridge between the magnetic centres, this chemical feature is put into context with changes in their magnetic relaxation.
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