1
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Bernbeck M, Orlova AP, Hilgar JD, Gembicky M, Ozerov M, Rinehart JD. Dipolar Coupling as a Mechanism for Fine Control of Magnetic States in ErCOT-Alkyl Molecular Magnets. J Am Chem Soc 2024; 146:7243-7256. [PMID: 38456803 PMCID: PMC10958522 DOI: 10.1021/jacs.3c10412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 02/13/2024] [Accepted: 02/14/2024] [Indexed: 03/09/2024]
Abstract
The design of molecular magnets has progressed greatly by taking advantage of the ability to impart successive perturbations and control vibronic transitions in 4fn systems through the careful manipulation of the crystal field. Herein, we control the orientation and rigidity of two dinuclear ErCOT-based molecular magnets: the inversion-symmetric bridged [ErCOT(μ-Me)(THF)]2 (2) and the nearly linear Li[(ErCOT)2(μ-Me)3] (3). The conserved anisotropy of the ErCOT synthetic unit facilitates the direction of the arrangement of its magnetic anisotropy for the purposes of generating controlled internal magnetic fields, improving control of the energetics and transition probabilities of the electronic angular momentum states with exchange biasing via dipolar coupling. This control is evidenced through the introduction of a second thermal barrier to relaxation operant at low temperatures that is twice as large in 3 as in 2. This barrier acts to suppress through-barrier relaxation by protecting the ground state from interacting with stray local fields while operating at an energy scale an order of magnitude smaller than the crystal field term. These properties are highlighted when contrasted against the mononuclear structure ErCOT(Bn)(THF)2 (1), in which quantum tunneling of the magnetization processes dominate, as demonstrated by magnetometry and ab initio computational methods. Furthermore, far-infrared magnetospectroscopy measurements reveal that the increased rigidity imparted by successive removal of solvent ligands when adding bridging methyl groups, along with the increased excited state purity, severely limits local spin-vibrational interactions that facilitate magnetic relaxation, manifesting as longer relaxation times in 3 relative to those in 2 as temperature is increased.
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Affiliation(s)
- Maximilian
G. Bernbeck
- Department
of Chemistry and Biochemistry, University
of California—San Diego, La Jolla, California 92093, United States
| | - Angelica P. Orlova
- Department
of Chemistry and Biochemistry, University
of California—San Diego, La Jolla, California 92093, United States
| | - Jeremy D. Hilgar
- Department
of Chemistry and Biochemistry, University
of California—San Diego, La Jolla, California 92093, United States
| | - Milan Gembicky
- Department
of Chemistry and Biochemistry, University
of California—San Diego, La Jolla, California 92093, United States
| | - Mykhaylo Ozerov
- National
High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States
| | - Jeffrey D. Rinehart
- Department
of Chemistry and Biochemistry, University
of California—San Diego, La Jolla, California 92093, United States
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2
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Li LL, Su HD, Liu S, Wang WZ. Enhancing the energy barrier by replacing the counterions in two holmium(iii)-pentagonal bipyramidal single-ion magnets. Dalton Trans 2020; 49:6703-6709. [PMID: 32367102 DOI: 10.1039/d0dt00905a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Based on a phosphine oxide ligand, HMPA (hexamethylphosphoric triamide), two mononuclear HoIII-pentagonal bipyramidal complexes were synthesized with the formulas [Ho(HMPA)2(H2O)5]2Cl6·2HMPA·2H2O (1) and [Ho(HMPA)2(H2O)5]Br3·2HMPA (2). Single-crystal X-ray diffraction results show that all HoIII ions in both the two complexes are hepta-coordinated and are located in pentagonal bipyramidal {HoO7} coordination polyhedrons constructed by two axial HMPA ligands and five equatorial water molecules. However, due to the employment of different halide ions as counterions, the second coordination sphere surrounding each [Ho(HMPA)2(H2O)5]3+ moiety is different in the two complexes: in 1, three Cl- ions, one water molecule and one HMPA ligand; in 2, three Br- ions and two HMPA ligands. Ac magnetic susceptibilities under zero dc field show that both the two complexes are single-ion magnets with effective energy barriers of 290 K and 320 K for 1 and 2, respectively. Compared with 1, the enhancement in the energy barrier of 2 is believed to be induced mainly by the change in the second coordination sphere rather than the minor differences in the {HoO7} polyhedrons.
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Affiliation(s)
- Lei-Lei Li
- College of Chemistry and Chemical Engineering, Xi'an Shiyou University, Xi'an, 710065, ShaanXi, China.
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3
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Krylov DS, Liu F, Brandenburg A, Spree L, Bon V, Kaskel S, Wolter AUB, Büchner B, Avdoshenko SM, Popov AA. Magnetization relaxation in the single-ion magnet DySc 2N@C 80: quantum tunneling, magnetic dilution, and unconventional temperature dependence. Phys Chem Chem Phys 2018; 20:11656-11672. [PMID: 29671443 PMCID: PMC5933001 DOI: 10.1039/c8cp01608a] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Quantum tunneling and relaxation of magnetization in single molecule magnet DySc2N@C80 is thoroughly studied as a function of magnetic dilution, temperature, and magnetic field.
Relaxation of magnetization in endohedral metallofullerenes DySc2N@C80 is studied at different temperatures, in different magnetic fields, and in different molecular arrangements. Magnetization behavior and relaxation are analyzed for powder sample, and for DySc2N@C80 diluted in non-magnetic fullerene Lu3N@C80, adsorbed in voids of a metal–organic framework, and dispersed in a polymer. The magnetic field dependence and zero-field relaxation are also studied for single-crystals of DySc2N@C80 co-crystallized with Ni(ii) octaethylporphyrin, as well as for the single crystal diluted with Lu3N@C80. Landau–Zener theory is applied to analyze quantum tunneling of magnetization in the crystals. The field dependence of relaxation rates revealed a dramatic dependence of the zero-field tunneling resonance width on the dilution and is explained with the help of an analysis of dipolar field distributions. AC magnetometry is used then to get access to the relaxation of magnetization in a broader temperature range, from 2 to 87 K. Finally, a theoretical framework describing the spin dynamics with dissipation is proposed to study magnetization relaxation phenomena in single molecule magnets.
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Affiliation(s)
- D S Krylov
- Leibniz Institute for Solid State and Materials Research, 01069 Dresden, Germany.
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4
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Zhang H, Nakanishi R, Katoh K, Breedlove BK, Kitagawa Y, Yamashita M. Low coordinated mononuclear erbium(iii) single-molecule magnets with C3v symmetry: a method for altering single-molecule magnet properties by incorporating hard and soft donors. Dalton Trans 2018; 47:302-305. [DOI: 10.1039/c7dt04053a] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Structures and magnetic characteristics of two three coordinate erbium(iii) compounds with C3v geometry, tris(2,6-di-tert-butyl-p-cresolate)erbium (1) and tris(bis(trimethylsilyl)methyl)erbium (2), were determined.
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Affiliation(s)
- Haitao Zhang
- Department of Chemistry
- Graduate School of Science
- Tohoku University
- Sendai 980-8578
- Japan
| | - Ryo Nakanishi
- Department of Chemistry
- Graduate School of Science
- Tohoku University
- Sendai 980-8578
- Japan
| | - Keiichi Katoh
- Department of Chemistry
- Graduate School of Science
- Tohoku University
- Sendai 980-8578
- Japan
| | - Brian K. Breedlove
- Department of Chemistry
- Graduate School of Science
- Tohoku University
- Sendai 980-8578
- Japan
| | - Yasutaka Kitagawa
- Department of Materials Engineering Science
- Graduate School of Engineering Science
- Osaka University
- Toyonaka
- Japan
| | - Masahiro Yamashita
- Department of Chemistry
- Graduate School of Science
- Tohoku University
- Sendai 980-8578
- Japan
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5
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Novitchi G, Shova S, Lan Y, Wernsdorfer W, Train C. Verdazyl Radical, a Building Block for a Six-Spin-Center 2p–3d–4f Single-Molecule Magnet. Inorg Chem 2016; 55:12122-12125. [DOI: 10.1021/acs.inorgchem.6b02380] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ghénadie Novitchi
- Laboratoire National
des Champs Magnétiques Intenses, UPR CNRS 3228, Université Grenoble-Alpes, B.P. 166, 38042 Grenoble Cedex
9, France
| | - Sergiu Shova
- “Petru Poni” Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, 700487 Iasi, Romania
| | - Yanhua Lan
- Institut Néel, UPR CNRS 2940, Université Grenoble-Alpes, B.P. 166, 38042 Grenoble Cedex 9, France
| | - Wolfgang Wernsdorfer
- Institut Néel, UPR CNRS 2940, Université Grenoble-Alpes, B.P. 166, 38042 Grenoble Cedex 9, France
| | - Cyrille Train
- Laboratoire National
des Champs Magnétiques Intenses, UPR CNRS 3228, Université Grenoble-Alpes, B.P. 166, 38042 Grenoble Cedex
9, France
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6
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Meng YS, Zhang YQ, Wang ZM, Wang BW, Gao S. Weak Ligand-Field Effect from Ancillary Ligands on Enhancing Single-Ion Magnet Performance. Chemistry 2016; 22:12724-31. [DOI: 10.1002/chem.201601934] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Yin-Shan Meng
- Beijing National Laboratory of Molecular Science; State Key Laboratory of Rare Earth Materials Chemistry and Applications; College of Chemistry and Molecular Engineering; Peking University; Beijing 100871 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
| | - Zhe-Ming Wang
- Beijing National Laboratory of Molecular Science; State Key Laboratory of Rare Earth Materials Chemistry and Applications; College of Chemistry and Molecular Engineering; Peking University; Beijing 100871 P. R. China
| | - Bing-Wu Wang
- Beijing National Laboratory of Molecular Science; State Key Laboratory of Rare Earth Materials Chemistry and Applications; College of Chemistry and Molecular Engineering; Peking University; Beijing 100871 P. R. China
| | - Song Gao
- Beijing National Laboratory of Molecular Science; State Key Laboratory of Rare Earth Materials Chemistry and Applications; College of Chemistry and Molecular Engineering; Peking University; Beijing 100871 P. R. China
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7
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Meng YS, Wang CH, Zhang YQ, Leng XB, Wang BW, Chen YF, Gao S. (Boratabenzene)(cyclooctatetraenyl) lanthanide complexes: a new type of organometallic single-ion magnet. Inorg Chem Front 2016. [DOI: 10.1039/c6qi00028b] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
(Boratabenzene)(cyclooctatetraenyl) lanthanide complexes were synthesized, and the erbium ones showed single-ion magnet behaviours. One complex exhibited hysteresis up to 8 K, and another one featured energy barrier of 300 cm−1.
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Affiliation(s)
- Yin-Shan Meng
- Beijing National Laboratory of Molecular Science
- State Key Laboratory of Rare Earth Materials Chemistry and Applications
- College of Chemistry and Molecular Engineering
- Peking University
- Beijing 100871
| | - Chun-Hong Wang
- State Key Laboratory of Organometallic Chemistry
- Shanghai Institute of Organic Chemistry
- Chinese Academy of Sciences
- Shanghai 200032
- 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
| | - Xue-Bing Leng
- State Key Laboratory of Organometallic Chemistry
- Shanghai Institute of Organic Chemistry
- Chinese Academy of Sciences
- Shanghai 200032
- P. R. China
| | - Bing-Wu Wang
- Beijing National Laboratory of Molecular Science
- State Key Laboratory of Rare Earth Materials Chemistry and Applications
- College of Chemistry and Molecular Engineering
- Peking University
- Beijing 100871
| | - Yao-Feng Chen
- State Key Laboratory of Organometallic Chemistry
- Shanghai Institute of Organic Chemistry
- Chinese Academy of Sciences
- Shanghai 200032
- P. R. China
| | - Song Gao
- Beijing National Laboratory of Molecular Science
- State Key Laboratory of Rare Earth Materials Chemistry and Applications
- College of Chemistry and Molecular Engineering
- Peking University
- Beijing 100871
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8
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Chien YL, Chang MW, Tsai YC, Lee GH, Sheu WS, Yang EC. New salen-type dysprosium(III) double-decker and triple-decker complexes. Polyhedron 2015. [DOI: 10.1016/j.poly.2015.07.048] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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9
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Schmid-Lorch D, Häberle T, Reinhard F, Zappe A, Slota M, Bogani L, Finkler A, Wrachtrup J. Relaxometry and Dephasing Imaging of Superparamagnetic Magnetite Nanoparticles Using a Single Qubit. NANO LETTERS 2015; 15:4942-4947. [PMID: 26218205 DOI: 10.1021/acs.nanolett.5b00679] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
To study the magnetic dynamics of superparamagnetic nanoparticles, we use scanning probe relaxometry and dephasing of the nitrogen vacancy (NV) center in diamond, characterizing the spin noise of a single 10 nm magnetite particle. Additionally, we show the anisotropy of the NV sensitivity's dependence on the applied decoherence measurement method. By comparing the change in relaxation (T1) and dephasing (T2) time in the NV center when scanning a nanoparticle over it, we are able to extract the nanoparticle's diameter and distance from the NV center using an Ornstein-Uhlenbeck model for the nanoparticle's fluctuations. This scanning probe technique can be used in the future to characterize different spin label substitutes for both medical applications and basic magnetic nanoparticle behavior.
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Affiliation(s)
| | | | | | | | | | - Lapo Bogani
- §Department of Materials, University of Oxford, 16 Parks Road, OX1 3PH, Oxford, United Kingdom
| | | | - Jörg Wrachtrup
- ∥Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
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10
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Single-Chain Magnets and Related Systems. MOLECULAR NANOMAGNETS AND RELATED PHENOMENA 2014. [DOI: 10.1007/430_2014_154] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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11
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Zhu YY, Cui C, Qian K, Yin J, Wang BW, Wang ZM, Gao S. A family of enantiopure FeIII4 single molecule magnets: fine tuning of energy barrier by remote substituent. Dalton Trans 2014; 43:11897-907. [DOI: 10.1039/c3dt53317d] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report a new family of enantiopure star-shaped FeIII4 single-molecule magnets (SMMs). Interestingly, the SMM properties of this series of clusters can be finely tuned by the remote substituent of the ligands.
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Affiliation(s)
- Yuan-Yuan Zhu
- Key Laboratory of Advanced Functional Materials and Devices
- Anhui Province
- and School of Chemical Engineering
- Hefei University of Technology
- Hefei, P. R. China
| | - Chang Cui
- Beijing National Laboratory for Molecular Sciences
- State Key Laboratory of Rare Earth Materials Chemistry and Applications
- College of Chemistry and Molecular Engineering
- Peking University
- Beijing 100871, P. R. China
| | - Kang Qian
- Beijing National Laboratory for Molecular Sciences
- State Key Laboratory of Rare Earth Materials Chemistry and Applications
- College of Chemistry and Molecular Engineering
- Peking University
- Beijing 100871, P. R. China
| | - Ji Yin
- Key Laboratory of Advanced Functional Materials and Devices
- Anhui Province
- and School of Chemical Engineering
- Hefei University of Technology
- Hefei, P. R. China
| | - Bing-Wu Wang
- Beijing National Laboratory for Molecular Sciences
- State Key Laboratory of Rare Earth Materials Chemistry and Applications
- College of Chemistry and Molecular Engineering
- Peking University
- Beijing 100871, P. R. China
| | - Zhe-Ming Wang
- Beijing National Laboratory for Molecular Sciences
- State Key Laboratory of Rare Earth Materials Chemistry and Applications
- College of Chemistry and Molecular Engineering
- Peking University
- Beijing 100871, P. R. China
| | - Song Gao
- Beijing National Laboratory for Molecular Sciences
- State Key Laboratory of Rare Earth Materials Chemistry and Applications
- College of Chemistry and Molecular Engineering
- Peking University
- Beijing 100871, P. R. China
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12
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Gao F, Cui L, Song Y, Li YZ, Zuo JL. Calix[4]arene-Supported Mononuclear Lanthanide Single-Molecule Magnet. Inorg Chem 2013; 53:562-7. [DOI: 10.1021/ic4026624] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Feng Gao
- State Key Laboratory of Coordination Chemistry, School of Chemistry
and Chemical Engineering, Nanjing National Laboratory of Microstructures, Nanjing University, Hankou Road 9, Nanjing 210093, P. R. China
- School
of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of Green
Synthetic Chemistry for Functional Materials, Jiangsu Normal University, Shanghai Road 101, Xuzhou 221116, P. R. China
| | - Long Cui
- State Key Laboratory of Coordination Chemistry, School of Chemistry
and Chemical Engineering, Nanjing National Laboratory of Microstructures, Nanjing University, Hankou Road 9, Nanjing 210093, P. R. China
| | - You Song
- State Key Laboratory of Coordination Chemistry, School of Chemistry
and Chemical Engineering, Nanjing National Laboratory of Microstructures, Nanjing University, Hankou Road 9, Nanjing 210093, P. R. China
| | - Yi-Zhi Li
- State Key Laboratory of Coordination Chemistry, School of Chemistry
and Chemical Engineering, Nanjing National Laboratory of Microstructures, Nanjing University, Hankou Road 9, Nanjing 210093, P. R. China
| | - Jing-Lin Zuo
- State Key Laboratory of Coordination Chemistry, School of Chemistry
and Chemical Engineering, Nanjing National Laboratory of Microstructures, Nanjing University, Hankou Road 9, Nanjing 210093, P. R. China
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13
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Wang BW, Wang XY, Sun HL, Jiang SD, Gao S. Evolvement of molecular nanomagnets in China. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2013; 371:20120316. [PMID: 24000367 DOI: 10.1098/rsta.2012.0316] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Molecular nanomagnets have been undergoing development for 20 years since the first single-molecule magnet (SMM), Mn₁₂Ac, was characterized as the molecule-behaved magnet. The multi-disciplinary scientists promoted the magnetic characteristics to be more suitable for use in information science and spintronics. The concept of molecular nanomagnets has also evolved to include single-chain magnets (SCMs), single-ion magnets (SIMs) and even magnetic molecules that showed only slow magnetic relaxation, in addition to the initial cluster-type SMMs. In this review, several aspects, including SMMs, SCMs and SIMs, are introduced briefly through some representative examples. In particular, the contribution of Chinese chemists is highlighted in the design, synthesis and understanding of various types of molecular nanomagnets.
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Affiliation(s)
- Bing-Wu Wang
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People's Republic of China
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14
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Ren M, Bao SS, Hoshino N, Akutagawa T, Wang B, Ding YC, Wei S, Zheng LM. Solvent Responsive Magnetic Dynamics of a Dinuclear Dysprosium Single-Molecule Magnet. Chemistry 2013; 19:9619-28. [DOI: 10.1002/chem.201300497] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Indexed: 11/06/2022]
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15
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Zhu YY, Cui C, Zhang YQ, Jia JH, Guo X, Gao C, Qian K, Jiang SD, Wang BW, Wang ZM, Gao S. Zero-field slow magnetic relaxation from single Co(ii) ion: a transition metal single-molecule magnet with high anisotropy barrier. Chem Sci 2013. [DOI: 10.1039/c3sc21893g] [Citation(s) in RCA: 266] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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16
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17
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Jiang SD, Liu SS, Zhou LN, Wang BW, Wang ZM, Gao S. Series of Lanthanide Organometallic Single-Ion Magnets. Inorg Chem 2012; 51:3079-87. [DOI: 10.1021/ic202511n] [Citation(s) in RCA: 210] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shang-Da Jiang
- Beijing National Laboratory of Molecular
Science, State Key Laboratory of Rare Earth Materials Chemistry and
Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
| | - Shan-Shan Liu
- Beijing National Laboratory of Molecular
Science, State Key Laboratory of Rare Earth Materials Chemistry and
Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
| | - Li-Nan Zhou
- Beijing National Laboratory of Molecular
Science, State Key Laboratory of Rare Earth Materials Chemistry and
Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
| | - Bing-Wu Wang
- Beijing National Laboratory of Molecular
Science, State Key Laboratory of Rare Earth Materials Chemistry and
Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
| | - Zhe-Ming Wang
- Beijing National Laboratory of Molecular
Science, State Key Laboratory of Rare Earth Materials Chemistry and
Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
| | - Song Gao
- Beijing National Laboratory of Molecular
Science, State Key Laboratory of Rare Earth Materials Chemistry and
Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
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18
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Duboc C, Ganyushin D, Sivalingam K, Collomb MN, Neese F. Systematic theoretical study of the zero-field splitting in coordination complexes of Mn(III). Density functional theory versus multireference wave function approaches. J Phys Chem A 2011; 114:10750-8. [PMID: 20828179 DOI: 10.1021/jp107823s] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This paper presents a detailed evaluation of the performance of density functional theory (DFT) as well as complete active space self-consistent field (CASSCF)-based methods (CASSCF and second-order N-electron valence state perturbation theory, NEVPT2) to predict the zero-field splitting (zfs) parameters for a series of coordination complexes containing the Mn(III) ion. The physical origin of the experimentally determined zfs's was investigated by studying the different contributions to these parameters. To this end, a series of mononuclear Mn(III) complexes was chosen for which the structures have been resolved by X-ray diffraction and the zfs parameters have been accurately determined by high-field EPR spectroscopy. In a second step, small models have been constructed to allow for a systematic assessment of the factors that dominate the variations in the observed zfs parameters and to establish magnetostructural correlations. Among the tested functionals, the best predictions have been obtained with B3LYP, followed by the nonhybrid BP86 functional, which in turn is more successful than the meta-hybrid GGA functional TPSSh. For the estimation of the spin-orbit coupling (SOC) part of the zfs, it was found that the coupled perturbed SOC approach CP is more successful than the Pederson-Khanna method. Concerning the spin-spin interaction (SS), the restricted open-shell Kohn-Sham (ROKS) approach led to a slightly better agreement with the experiment than the unrestricted KS (UKS) approach. The ab initio state-averaged CASSCF (SA-CASSCF) method with a minimal active space and the most recent implementation that treats the SOC and SS contributions on an equal footing provides the best predictions for the zfs. The analysis demonstrates that the major contribution to the axial zfs parameter (D) originates from the SOC interaction but that the SS part is far from being negligible (between 10 and 20% of D). Importantly, the various excited triplet ligand field states account for roughly half of the value of D, contrary to popular ligand field models. Despite covering dynamic correlation contributions to the transition energies, NEVPT2 does not lead to large improvements in the results as the excitation energies of the Mn(III) d-d transitions are already fairly accurate at the SA-CASSCF level. For a given type of coordination sphere (e.g., elongated or compressed octahedron), the magnetic anisotropy of the Mn(III) ion, D, does not appear to be highly sensitive to the nature of the ligands, while the E/D ratio is notably affected by all octahedral distortions. Furthermore, the introduction of different halides into the coordination sphere of Mn(III) only leads to small effects on D. Nevertheless, it appears that oxygen-based ligands afford larger D values than nitrogen-based ligands.
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Affiliation(s)
- Carole Duboc
- Département de Chimie Moléculaire, UMR-5250, Laboratoire de Chimie Inorganique Redox, Institut de Chimie Moléculaire de Grenoble FR- CNRS-2607, Université Joseph Fourier Grenoble 1/CNRS, BP-53, 38041 Grenoble Cedex 9, France.
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