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Cui HH, Xu H, Zhang T, Chen Q, Luo S, Wang M, Wang J, Chen L, Zhang M, Tang Y. Magnetic Anisotropy and Relaxation in Four-Coordinate Cobalt(II) Single-Ion Magnets with a [Co IIO 4] Core. Inorg Chem 2024; 63:9050-9057. [PMID: 38709957 DOI: 10.1021/acs.inorgchem.4c00008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
A mononuclear four-coordinate Co(II) complex with a [CoIIO4] core, namely, PPN[Li(MeOH)4][Co(L)2] (1) (PPN = bis(phosphoranediyl)iminium; H2L = perfluoropinacol), has been studied by X-ray crystallography, magnetic characterization, and theoretical calculations. This complex presents a severely distorted coordination geometry. The O-Co-O bite angle is 83.42°/83.65°, and the dihedral twist angle between the O-Co-O chelate planes is 55.6°. The structural distortion results in a large easy-axis magnetic anisotropy with D = -104(1) cm-1 and a transverse component with |E| = +4(2) cm-1. Alternating current (ac) susceptibility measurements demonstrate that 1 exhibits slow relaxation of magnetization at zero static field. However, the frequency-dependent out-of-phase (χ"M) susceptibilities of 1 at 0 Oe do not show a characteristic maximum. Upon the application of a dc field or the dilution with a diamagnetic Zn matrix, the quantum tunneling of magnetization (QTM) process can be successfully suppressed. Notably, after dilution with the Zn matrix, the obtained sample exhibits a structure different from that of the pristine complex. In this altered sample, the asymmetric unit does not contain the Li(MeOH)4+ cation, resulting in an O-Co-O bite angle of 86.05° and a dihedral twist angle of 75.84°, thereby leading to an approximate D2d symmetry. Although such differences are not desirable for magnetic studies, this study still gives some insights. Theoretical calculations reveal that the D parameter is governed by the O-Co-O bite angle, in line with our previous report for other tetrahedral Co(II) complex with a [CoIIN4] core. On the other hand, the rhombic component is found to increase as the dihedral angle deviates from 90°. These findings provide valuable guidelines for fine-tuning the magnetic properties of Co(II) complexes.
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Affiliation(s)
- Hui-Hui Cui
- School of Chemistry and Chemical Engineering, Nantong University, Nantong 226019, China
| | - Hongjuan Xu
- School of Chemistry and Chemical Engineering, Nantong University, Nantong 226019, China
| | - Tengkun Zhang
- School of Chemistry and Chemical Engineering, Nantong University, Nantong 226019, China
| | - Qiukai Chen
- School of Chemistry and Chemical Engineering, Nantong University, Nantong 226019, China
| | - Shuchang Luo
- School of Chemical Engineering, Guizhou University of Engineering Science, Bijie 551700, China
| | - Miao Wang
- School of Chemistry and Chemical Engineering, Nantong University, Nantong 226019, China
| | - Jin Wang
- School of Chemistry and Chemical Engineering, Nantong University, Nantong 226019, China
| | - Lei Chen
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, China
| | - Mingxing Zhang
- School of Chemistry and Chemical Engineering, Nantong University, Nantong 226019, China
| | - Yanfeng Tang
- School of Chemistry and Chemical Engineering, Nantong University, Nantong 226019, China
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Juráková J, Šalitroš I. Co(II) single-ion magnets: synthesis, structure, and magnetic properties. MONATSHEFTE FUR CHEMIE 2022; 153:1001-1036. [PMID: 35615113 PMCID: PMC9123880 DOI: 10.1007/s00706-022-02920-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 04/25/2022] [Indexed: 01/01/2023]
Abstract
Magnetoactive coordination compounds exhibiting bi- or multistability between two or more magnetic stable states present an attractive example of molecular switches. Currently, the research is focused on molecular nanomagnets, especially single molecule magnets (SMMs), which are molecules, where the slow relaxation of the magnetization based on the purely molecular origin is observed. Contrary to ferromagnets, the magnetic bistability of SMMs does not require intermolecular interactions, which makes them particularly interesting in terms of application potential, especially in the high-density storage of data. This paper aims to introduce the readers into a basic understanding of SMM behaviour, and furthermore, it provides an overview of the attractive Co(II) SMMs with emphasis on the relation between structural features, magnetic anisotropy, and slow relaxation of magnetization in tetra-, penta-, and hexacoordinate complexes. Graphical abstract
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Affiliation(s)
- Jana Juráková
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 61200 Brno, Czech Republic
| | - 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, 81237 Slovakia
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 771 46, Olomouc, Czech Republic
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Lv W, Cui HH, Chen L, Zhang YQ, Chen XT, Wang Z, Ouyang ZW, Xue ZL. Magnetic anisotropy of two tetrahedral Co(II)-halide complexes with triphenylphosphine ligands. Dalton Trans 2022; 51:7530-7538. [PMID: 35506535 DOI: 10.1039/d2dt00121g] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recently, the choice of ligand and geometric control of mononuclear complexes, which can affect the relaxation pathways and blocking temperature, have received wide attention in the field of single-ion magnets (SIMs). To find out the influence of the coordination environment on SIMs, two four-coordinate mononuclear Co(II) complexes [NEt4][Co(PPh3)X3] (X = Cl-, 1; Br-, 2) have been synthesized and studied by X-ray single crystallography, magnetic measurements, high-frequency and -field EPR (HF-EPR) spectroscopy and theoretical calculations. Both complexes are in a cubic space group Pa3̄ (No. 205), containing a slightly distorted tetrahedral moiety with crystallographically imposed C3v symmetry through the [Co(PPh3)X3]- anion. The direct-current (dc) magnetic data and HF-EPR spectroscopy indicated the anisotropic S = 3/2 spin ground states of the Co(II) ions with the easy-plane anisotropy for 1 and 2. Ab initio calculations were performed to confirm the positive magnetic anisotropies of 1 and 2. Frequency- and temperature-dependent alternating-current (ac) magnetic susceptibility measurements revealed slow magnetic relaxation for 1 and 2 at an applied dc field. Finally, the magnetic properties of 1 and 2 were compared to those of other Co(II) complexes with a [CoAB3] moiety.
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Affiliation(s)
- Wei Lv
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
| | - Hui-Hui Cui
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
| | - Lei Chen
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, China
| | - Yi-Quan Zhang
- Jiangsu Key Laboratory for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing 210023, China
| | - Xue-Tai Chen
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
| | - Zhenxing Wang
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zhong-Wen Ouyang
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zi-Ling Xue
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA
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Ishizaki T, Karasaki H, Kage Y, Kamioka M, Wang Y, Mori S, Ishikawa N, Fukuda T, Furuta H, Shimizu S. Janus Pyrrolopyrrole Aza-dipyrrin: Hydrogen-Bonded Assemblies and Slow Magnetic Relaxation of the Cobalt(II) Complex in the Solid State. Chemistry 2021; 27:12686-12692. [PMID: 34137468 DOI: 10.1002/chem.202101755] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Indexed: 11/12/2022]
Abstract
A novel pyrrolopyrrole azadipyrrin (Janus-PPAD) with Janus duality was synthesized by a Schiff base-forming reaction of diketopyrrolopyrrole. The orthogonal interactions of the hydrogen-bonding ketopyrrole and metal-coordinating azadipyrrin moieties in Janus-PPAD enabled the metal ions to be arranged at regular intervals: zinc(II) and cobalt(II) coordination provided metal-coordinated Janus-PPAD dimers, which can subsequently form hydrogen-bonded one-dimensional arrays both in solution and in the solid state. The supramolecular assembly of the zinc(II) complex in solution was investigated by 1 H NMR spectroscopy based on the isodesmic model, in which a binding constant for the elongation of assemblies is constant. Owing to the tetrahedral coordination, in the solid state, the cobalt(II) complex exhibited a slow magnetic relaxation due to the negative D value of -27.1 cm-1 with an effective relaxation energy barrier Ueff of 38.0 cm-1 . The effect of magnetic dilution on the relaxation behavior is discussed. The relaxation mechanism at low temperature was analyzed by considering spin lattice interactions and quantum tunneling effects. The easy-axis magnetic anisotropy was confirmed, and the relevant wave functions were obtained by ab initio CASSCF calculations.
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Affiliation(s)
- Toshiharu Ishizaki
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, 560-0043, Japan.,Current address: Department of Chemistry, College of Humanities and Sciences, Nihon University, Tokyo, 156-8550, Japan
| | - Hideaki Karasaki
- Department of Chemistry and Biochemistry, Graduate School of Engineering and, Center for Molecular Systems (CMS), Kyushu University, Fukuoka, 819-0395, Japan
| | - Yuto Kage
- Department of Chemistry and Biochemistry, Graduate School of Engineering and, Center for Molecular Systems (CMS), Kyushu University, Fukuoka, 819-0395, Japan
| | - Misaki Kamioka
- Department of Chemistry and Biochemistry, Graduate School of Engineering and, Center for Molecular Systems (CMS), Kyushu University, Fukuoka, 819-0395, Japan
| | - Yitong Wang
- Department of Chemistry and Biochemistry, Graduate School of Engineering and, Center for Molecular Systems (CMS), Kyushu University, Fukuoka, 819-0395, Japan
| | - Shigeki Mori
- Advanced Research Support Center (ADRES), Ehime University, Matsuyama, 790-8577, Japan
| | - Naoto Ishikawa
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, 560-0043, Japan
| | - Takamitsu Fukuda
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, 560-0043, Japan
| | - Hiroyuki Furuta
- Department of Chemistry and Biochemistry, Graduate School of Engineering and, Center for Molecular Systems (CMS), Kyushu University, Fukuoka, 819-0395, Japan
| | - Soji Shimizu
- Department of Chemistry and Biochemistry, Graduate School of Engineering and, Center for Molecular Systems (CMS), Kyushu University, Fukuoka, 819-0395, Japan
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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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Reczyński M, Akaki M, Fukuda T, Sawada Y, Nishii K, Hagiwara M, Nitek W, Sieklucka B, Nowicka B. Hepta-coordinated Ni(II) assemblies - structure and magnetic studies. Dalton Trans 2021; 50:5251-5261. [PMID: 33881078 DOI: 10.1039/d1dt00479d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two mononuclear complexes [Ni(dapsc)(H2O)2]Cl(NO3)·H2O (1) and [Ni(dapsc)(NCS)2] (2), and a bimetallic CN-bridged trinuclear molecule [NiII(dapsc)(H2O)]2[WIV(CN)8]·11H2O (3) (dapsc = 2,6-diacetylpyridine-bis(semicarbazone)) were synthesised and characterised in terms of structure and magnetic properties. All three compounds contain Ni(ii) ions in a pentagonal bipyramid coordination geometry afforded by the equatorial pentadentate ligand (dapsc) and two O- or N-donating axial ligands. The compounds differ in the relative arrangement of the complexes, intermolecular interactions and distortion from the ideal coordination geometry. The high-field EPR and magnetometric studies show large anisotropy of the Ni(ii) centres with the D parameters in the range of -10.5 to -21.2 cm-1 and negligible antiferromagnetic interactions. The easy-axis magnetic anisotropies of 1-3 were reproduced by ab initio CASSCF/NEVPT2 calculations. The ground states consist mainly of the |MS = |±1 states, which is consistent with the fact that no out-of-phase signal can be detected in the AC magnetic susceptibility measurements.
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Affiliation(s)
- Mateusz Reczyński
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland.
| | - Mitsuru Akaki
- Center for Advanced High Magnetic Field Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Takamitsu Fukuda
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Yuya Sawada
- Center for Advanced High Magnetic Field Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Kengo Nishii
- Center for Advanced High Magnetic Field Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Masayuki Hagiwara
- Center for Advanced High Magnetic Field Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Wojciech Nitek
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland.
| | - Barbara Sieklucka
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland.
| | - Beata Nowicka
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland.
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Mitsuhashi R, Hosoya S, Suzuki T, Sunatsuki Y, Sakiyama H, Mikuriya M. Zero-field slow relaxation of magnetization in cobalt(ii) single-ion magnets: suppression of quantum tunneling of magnetization by tailoring the intermolecular magnetic coupling. RSC Adv 2020; 10:43472-43479. [PMID: 35519684 PMCID: PMC9058397 DOI: 10.1039/d0ra08286d] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 11/23/2020] [Indexed: 12/03/2022] Open
Abstract
The correlation between magnetic relaxation dynamics and the alignment of single-ion magnets (SIMs) in a crystal was investigated using four analogous cobalt(ii) complexes with unique hydrogen-bond networks. The hydrogen-bonding interactions in the crystals resulted in a relatively short intermolecular Co⋯Co distance, which led to non-zero intermolecular magnetic coupling. All the complexes with a Co⋯Co distance shorter than 6.5 Å exhibited zero-field slow magnetic relaxation as weak magnetic interactions split the ground ±Ms levels and suppressed quantum tunneling of magnetization (QTM). In particular, antiferromagnetically coupled one-dimensional chain SIM networks effectively suppressed QTM when the two intrachain Co⋯Co distances were non-equivalent. However, when the two distances in a chain were equivalent and each molecular symmetry axis aligned parallell within the chain, QTM suppression was insufficient because magnetic coupling from the adjacent molecules was virtually cancelled. Partial substitution of the CoII ion with the diamagnetic ZnII ion up to 33% for this complex resulted in complete QTM suppression in the absence of an external field. These results show that the manipulation of intermolecular distances and alignments is effective for suppressing undesired QTM events in SIMs.
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Affiliation(s)
- Ryoji Mitsuhashi
- Institute of Liberal Arts and Science, Kanazawa University Kakuma Kanazawa Ishikawa 920-1192 Japan
| | - Satoshi Hosoya
- School of Science and Technology, Kwansei Gakuin University 2-1 Gakuen Sanda Hyogo 669-1337 Japan
| | - Takayoshi Suzuki
- Research Institute for Interdisciplinary Science, Okayama University 3-1-1 Tsushima-naka, Kita-ku Okayama 700-8530 Japan
| | - Yukinari Sunatsuki
- Department of Chemistry, Faculty of Science, Okayama University 3-1-1 Tsushima-naka, Kita-ku Okayama 700-8530 Japan
| | - Hiroshi Sakiyama
- Department of Science, Faculty of Science, Yamagata University 1-4-12 Kojirakawa Yamagata 990-8560 Japan
| | - Masahiro Mikuriya
- School of Science and Technology, Kwansei Gakuin University 2-1 Gakuen Sanda Hyogo 669-1337 Japan
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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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Xi L, Sun J, Wang K, Lu J, Jing P, Li L. Slow magnetic relaxation in CoII–LnIII heterodinuclear complexes achieved through a functionalized nitronyl nitroxide biradical. Dalton Trans 2020; 49:1089-1096. [DOI: 10.1039/c9dt04036f] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Five nitronyl nitroxide biradical-CoII–LnIII heterodinuclear complexes were achieved and the DyCo derivative displayed visible temperature/frequency-dependent χ′′ peaks, indicating the SMM behavior.
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Affiliation(s)
- Lu Xi
- Department of Chemistry
- Key Laboratory of Advanced Energy Materials Chemistry
- College of Chemistry
- Nankai University
- Tianjin 300071
| | - Juan Sun
- Department of Chemistry
- Key Laboratory of Advanced Energy Materials Chemistry
- College of Chemistry
- Nankai University
- Tianjin 300071
| | - Kang Wang
- Department of Chemistry
- Key Laboratory of Advanced Energy Materials Chemistry
- College of Chemistry
- Nankai University
- Tianjin 300071
| | - Jiao Lu
- Department of Chemistry
- Key Laboratory of Advanced Energy Materials Chemistry
- College of Chemistry
- Nankai University
- Tianjin 300071
| | - Pei Jing
- Department of Chemistry
- Key Laboratory of Advanced Energy Materials Chemistry
- College of Chemistry
- Nankai University
- Tianjin 300071
| | - Licun Li
- Department of Chemistry
- Key Laboratory of Advanced Energy Materials Chemistry
- College of Chemistry
- Nankai University
- Tianjin 300071
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