1
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Nath M, Joshi S, Mishra S. Ab initio calculation of magnetic anisotropy and thermal spin transition in the variable temperature crystal conformations of [Co(terpy) 2] 2. Phys Chem Chem Phys 2024; 26:15405-15416. [PMID: 38747204 DOI: 10.1039/d4cp00591k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
The structure-property correlation of [Co(terpy)2]2+, which shows a spin crossover at 270 K, has been computationally investigated based on its variable temperature crystal structures. Among the employed DFT functionals, only the re-parametrized hybrid B3LYP* functional could describe the correct spin transition temperature. Explicit consideration of metal-ligand sigma bonding with dynamic electron correlation is found to be necessary for an accurate determination of the SCO temperature with multi-reference calculations. The metal-ligand axial bond distances are found to be the most significant internal coordinates in deciding SCO. A small structural change along the axial distance causes a change in the t2g orbital splitting pattern and a reorientation of the magnetization axes at the SCO temperature. The complex shows an unusual triaxial magnetic anisotropy, with an easy axis of magnetization developing at higher temperatures. The strong coupling of low-frequency wagging motion of the two terpyridine ligands with the spin states of the complex provides an effective pathway for the relaxation of magnetization, resulting in a small magnetic anisotropy barrier.
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Affiliation(s)
- Moromi Nath
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, India.
| | - Shalini Joshi
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, India.
| | - Sabyashachi Mishra
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, India.
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2
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Chen QW, Ding YS, Zhu XF, Wang BW, Zheng Z. Substituent Positioning Effects on the Magnetic Properties of Sandwich-Type Erbium(III) Complexes with Bis(trimethylsilyl)-Substituted Cyclooctatetraenyl Ligands. Inorg Chem 2024; 63:9511-9519. [PMID: 38135507 DOI: 10.1021/acs.inorgchem.3c03369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2023]
Abstract
Lanthanide complexes with judiciously designed ligands have been extensively studied for their potential applications as single-molecule magnets. With the influence of ligands on their magnetic properties generally established, recent research has unearthed certain effects inherent to site differentiation due to the different types and varying numbers of substituents on the same ligand platform. Using two new sandwich-type Er(III) complexes with cyclooctatetraenyl (COT) ligands featuring two differently positioned trimethylsilyl (TMS) substituents, namely, [Li(DME)Er(COT1,5-TMS2)2]n (Er1) and [Na(DME)3][Er(COT1,3-TMS2)2] (Er2) [COT1,3-TMS2 and COT1,5-TMS2 donate 1,3- and 1,5-bis(trimethylsilyl)-substituted cyclooctatetraenyl ligands, respectively; DME = 1,2-dimethoxyethane], and with reference to previously reported [Li(DME)3][Er(COT1,4-TMS2)2] (A) and [K(DME)2][Er(COT1,4-TMS2)2] (B), any possible substituent position effects have been explored for the first time. The rearrangement of the TMS substituents from the starting COT1,4-TMS2 to COT1,3-TMS2 and COT1,5-TMS2, by way of formal migration of the TMS group, was thermally induced in the case of Er1, while for the formation of Er2, the use of Na+ in the placement of its Li+ and K+ congeners is essential. Both Er1 and Er2 display single-molecule magnetic behaviors with energy barriers of 170(3) and 172(6) K, respectively. Magnetic hysteresis loops, butterfly-shaped for Er1 and wide open for Er2, were observed up to 12 K for Er1 and 13 K for Er2. Studies of magnetic dynamics reveal the different pathways for relaxation of magnetization below 10 K, mainly by the Raman process for Er1 and by quantum tunneling of magnetization for Er2, leading to the order of magnitude difference in magnetic relaxation times and sharply different magnetic hysteresis loops.
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Affiliation(s)
- Qi-Wei Chen
- School of Chemistry and Life Science, Changchun University of Technology, Changchun 130012, China
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - You-Song Ding
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
- Key University Laboratory of Rare Earth Chemistry of Guangdong, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Xiao-Fei Zhu
- School of Chemistry and Life Science, Changchun University of Technology, Changchun 130012, China
| | - Bing-Wu Wang
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Zhiping Zheng
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
- Key University Laboratory of Rare Earth Chemistry of Guangdong, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
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3
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Zhu Y, Mahoney J, Babson AJ, Zhou Z, Wei Z, Gakiya-Teruya M, McNeely J, Rogachev AY, Shatruk M, Petrukhina MA. Homoleptic Rare-Earth-Metal Sandwiches with Dibenzo[ a, e]cyclooctatetraene Dianions. Inorg Chem 2024; 63:9579-9587. [PMID: 38374612 PMCID: PMC11134502 DOI: 10.1021/acs.inorgchem.3c04249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 02/01/2024] [Accepted: 02/02/2024] [Indexed: 02/21/2024]
Abstract
A family of rare-earth complexes [RE(III) = Y, La, Gd, Tb, Dy, and Er] with doubly reduced dibenzo[a,e]cyclooctatetraene (DBCOT) has been synthesized and structurally characterized. X-ray diffraction analysis confirms that all products of the [RE(DBCOT)(THF)4][RE(DBCOT)2] composition consist of the anionic sandwich [RE(DBCOT)2]- and the cationic counterpart [RE(DBCOT)(THF)4]+. Within the sandwich, two elongated π decks are slightly bent toward the metal center (avg. 7.3°) with a rotation angle of 35.9-37.6°. The RE(III) ion is entrapped between the central eight-membered rings of DBCOT2- in a η8 fashion. The trends in the RE-COT bond lengths are consistent with the variations of the ionic radii of RE(III) centers. The 1H NMR spectra of the diamagnetic Y(III) and La(III) analogues illustrate the distinct solution behavior for the cationic and anionic parts in this series. Magnetic measurements for the Dy analogue reveal single-molecule magnetism, which was rationalized by considering the effect of crystal-field splitting for both building units analyzed by electronic structure calculations.
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Affiliation(s)
- Yikun Zhu
- Department
of Chemistry, University at Albany, State
University of New York, Albany, New York 12222, United States
| | - James Mahoney
- Department
of Chemistry, University at Albany, State
University of New York, Albany, New York 12222, United States
| | - Aaron J. Babson
- Department
of Chemistry, University at Albany, State
University of New York, Albany, New York 12222, United States
| | - Zheng Zhou
- Department
of Chemistry, University at Albany, State
University of New York, Albany, New York 12222, United States
- Interdisciplinary
Materials Research Center, School of Materials Science and Engineering, Tongji University, Shanghai 201804, China
| | - Zheng Wei
- Department
of Chemistry, University at Albany, State
University of New York, Albany, New York 12222, United States
| | - Miguel Gakiya-Teruya
- Department
of Chemistry and Biochemistry, Florida State
University, Tallahassee, Florida 32306, United States
| | - James McNeely
- Department
of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Andrey Yu. Rogachev
- Department
of Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616, United States
| | - Michael Shatruk
- Department
of Chemistry and Biochemistry, Florida State
University, Tallahassee, Florida 32306, United States
| | - Marina A. Petrukhina
- Department
of Chemistry, University at Albany, State
University of New York, Albany, New York 12222, United States
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4
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Zakrzewski J, Liberka M, Wang J, Chorazy S, Ohkoshi SI. Optical Phenomena in Molecule-Based Magnetic Materials. Chem Rev 2024; 124:5930-6050. [PMID: 38687182 PMCID: PMC11082909 DOI: 10.1021/acs.chemrev.3c00840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
Since the last century, we have witnessed the development of molecular magnetism which deals with magnetic materials based on molecular species, i.e., organic radicals and metal complexes. Among them, the broadest attention was devoted to molecule-based ferro-/ferrimagnets, spin transition materials, including those exploring electron transfer, molecular nanomagnets, such as single-molecule magnets (SMMs), molecular qubits, and stimuli-responsive magnetic materials. Their physical properties open the application horizons in sensors, data storage, spintronics, and quantum computation. It was found that various optical phenomena, such as thermochromism, photoswitching of magnetic and optical characteristics, luminescence, nonlinear optical and chiroptical effects, as well as optical responsivity to external stimuli, can be implemented into molecule-based magnetic materials. Moreover, the fruitful interactions of these optical effects with magnetism in molecule-based materials can provide new physical cross-effects and multifunctionality, enriching the applications in optical, electronic, and magnetic devices. This Review aims to show the scope of optical phenomena generated in molecule-based magnetic materials, including the recent advances in such areas as high-temperature photomagnetism, optical thermometry utilizing SMMs, optical addressability of molecular qubits, magneto-chiral dichroism, and opto-magneto-electric multifunctionality. These findings are discussed in the context of the types of optical phenomena accessible for various classes of molecule-based magnetic materials.
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Affiliation(s)
- Jakub
J. Zakrzewski
- Faculty
of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
- Doctoral
School of Exact and Natural Sciences, Jagiellonian
University, Lojasiewicza
11, 30-348 Krakow, Poland
| | - Michal Liberka
- Faculty
of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
- Doctoral
School of Exact and Natural Sciences, Jagiellonian
University, Lojasiewicza
11, 30-348 Krakow, Poland
| | - Junhao Wang
- Department
of Materials Science, Faculty of Pure and Applied Science, University of Tsukuba, 1-1-1 Tonnodai, Tsukuba, Ibaraki 305-8573, Japan
| | - Szymon Chorazy
- Faculty
of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
| | - Shin-ichi Ohkoshi
- Department
of Chemistry, School of Science, The University
of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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5
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Stewart R, Canaj AB, Liu S, Regincós Martí E, Celmina A, Nichol G, Cheng HP, Murrie M, Hill S. Engineering Clock Transitions in Molecular Lanthanide Complexes. J Am Chem Soc 2024; 146:11083-11094. [PMID: 38619978 PMCID: PMC11046435 DOI: 10.1021/jacs.3c09353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 03/11/2024] [Accepted: 03/27/2024] [Indexed: 04/17/2024]
Abstract
Molecular lanthanide (Ln) complexes are promising candidates for the development of next-generation quantum technologies. High-symmetry structures incorporating integer spin Ln ions can give rise to well-isolated crystal field quasi-doublet ground states, i.e., quantum two-level systems that may serve as the basis for magnetic qubits. Recent work has shown that symmetry lowering of the coordination environment around the Ln ion can produce an avoided crossing or clock transition within the ground doublet, leading to significantly enhanced coherence. Here, we employ single-crystal high-frequency electron paramagnetic resonance spectroscopy and high-level ab initio calculations to carry out a detailed investigation of the nine-coordinate complexes, [HoIIIL1L2], where L1 = 1,4,7,10-tetrakis(2-pyridylmethyl)-1,4,7,10-tetraaza-cyclododecane and L2 = F- (1) or [MeCN]0 (2). The pseudo-4-fold symmetry imposed by the neutral organic ligand scaffold (L1) and the apical anionic fluoride ion generates a strong axial anisotropy with an mJ = ±8 ground-state quasi-doublet in 1, where mJ denotes the projection of the J = 8 spin-orbital moment onto the ∼C4 axis. Meanwhile, off-diagonal crystal field interactions give rise to a giant 116.4 ± 1.0 GHz clock transition within this doublet. We then demonstrate targeted crystal field engineering of the clock transition by replacing F- with neutral MeCN (2), resulting in an increase in the clock transition frequency by a factor of 2.2. The experimental results are in broad agreement with quantum chemical calculations. This tunability is highly desirable because decoherence caused by second-order sensitivity to magnetic noise scales inversely with the clock transition frequency.
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Affiliation(s)
- Robert Stewart
- National
High Magnetic Field Laboratory, Florida
State University, Tallahassee, Florida 32310, United States
- Department
of Physics, Florida State University, Tallahassee, Florida 32306, United States
- Center
for Molecular Magnetic Quantum Materials, University of Florida, Gainesville, Florida 32611, United States
| | - Angelos B. Canaj
- School
of Chemistry, University of Glasgow, University Avenue, Glasgow G12 8QQ, U.K.
| | - Shuanglong Liu
- Center
for Molecular Magnetic Quantum Materials, University of Florida, Gainesville, Florida 32611, United States
- Department
of Physics, Northeastern University, Boston, Massachusetts 02115, United States
| | - Emma Regincós Martí
- School
of Chemistry, University of Glasgow, University Avenue, Glasgow G12 8QQ, U.K.
| | - Anna Celmina
- School
of Chemistry, University of Glasgow, University Avenue, Glasgow G12 8QQ, U.K.
| | - Gary Nichol
- EastCHEM
School of Chemistry, The University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland, U.K.
| | - Hai-Ping Cheng
- Center
for Molecular Magnetic Quantum Materials, University of Florida, Gainesville, Florida 32611, United States
- Department
of Physics, Northeastern University, Boston, Massachusetts 02115, United States
| | - Mark Murrie
- School
of Chemistry, University of Glasgow, University Avenue, Glasgow G12 8QQ, U.K.
| | - Stephen Hill
- National
High Magnetic Field Laboratory, Florida
State University, Tallahassee, Florida 32310, United States
- Department
of Physics, Florida State University, Tallahassee, Florida 32306, United States
- Center
for Molecular Magnetic Quantum Materials, University of Florida, Gainesville, Florida 32611, United States
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6
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Nain S, Mukhopadhyaya A, Ali ME. Unravelling the Highest Magnetic Anisotropy Among all the nd-Shells in [WCp2]0 Metallocene. Inorg Chem 2024; 63:7401-7411. [PMID: 38578709 DOI: 10.1021/acs.inorgchem.4c00437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2024]
Abstract
Single-molecule magnets (SMMs) with a large magnetization reversal barrier are predominated by the lanthanide systems due to their strong spin-orbit coupling (SOC). However, the transition metals have also emerged as potential contenders and the largest magnetic anisotropy has been identified for a cobalt system among any d-series-based SMMs (Bunting et al. Science 2018, 362, eaat7319). In this work, we have explored the magnetic anisotropy in highly axial ligand field systems of metallocene, having different d-subshell (3d4, 4d4, and 5d4). The wave function-based multireference methods including static and dynamic electron correlations have been employed to investigate the zero-field splitting (ZFS) parameters. Here, we report exceptionally large magnetic anisotropy for a 5d complex of [WCp2]0 with the highest energy barrier that is nearly twice as high as the previous record value for the Co complex. We have also observed that the axial ZFS parameter (D) is increasing down the group in the order of 3d < 4d < 5d, pertaining to a large SOC.
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Affiliation(s)
- Sakshi Nain
- Institute of Nano Science and Technology, Sector-81, Mohali, Punjab 140306, India
| | - Aritra Mukhopadhyaya
- Institute of Nano Science and Technology, Sector-81, Mohali, Punjab 140306, India
| | - Md Ehesan Ali
- Institute of Nano Science and Technology, Sector-81, Mohali, Punjab 140306, India
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7
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Selikhov AN, Félix G, Lyubov DM, Nelyubina YV, Cherkasov AV, Sene S, Taydakov IV, Metlin MT, Tyutyunov AA, Guari Y, Larionova J, Trifonov AA. Luminescent Er 3+ based single molecule magnets with fluorinated alkoxide or aryloxide ligands. Dalton Trans 2024; 53:6352-6366. [PMID: 38488577 DOI: 10.1039/d3dt04375d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
We report the synthesis, structures, and magnetic and luminescence properties of a series of new mono- and dinuclear Er3+ complexes derived from sterically demanding aryloxide and fluorinated alkoxide ligands: [4-tBu-2,6-(Ph2CH)2C6H2O]3Er(THF) (1), [(C6F5)3CO]3Er(Me3SiOH) (2), [(C6F5)3CO]3Er[(Me3Si)2NH] (3), [(C6F5)3CO]3Er(C6H5CH3) (4), [(C6F5)3CO]3Er(o-Me2NC6H4CH3) (5) and {[Ph(CF3)2CO]2Er(μ2-OC(CF3)2Ph)}2 (6). In compounds 1, 2, and 4, the Er3+ ion is four-coordinated and adopts a distorted trigonal pyramidal geometry, while in 3, 5, and 6, the coordination geometry of Er3+ is impacted by the presence of several relatively short Er⋯F distances, making them rather 6-coordinated. All compounds behave as field-induced Single Molecule Magnets (SMMs) and exhibit an Er3+ characteristic near infrared (NIR) emission associated with the 4I13/2 → 4I15/2 transition with a remarkably long lifetime going up to 73 μs, which makes them multifunctional luminescent SMMs. The deconvolution of the NIR emission spectra allowed us to provide a direct probe of the crystal field splitting in these compounds, which was correlated with magnetic data.
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Affiliation(s)
- Alexander N Selikhov
- A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, 28 Vavilova str., 119334, Moscow, Russia.
- Institute of Organometallic Chemistry of Russian Academy of Sciences, 49 Tropinina str., GSP-445, 630950, Nizhny Novgorod, Russia
| | - Gautier Félix
- ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France.
| | - Dmitry M Lyubov
- A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, 28 Vavilova str., 119334, Moscow, Russia.
- Institute of Organometallic Chemistry of Russian Academy of Sciences, 49 Tropinina str., GSP-445, 630950, Nizhny Novgorod, Russia
| | - Yulia V Nelyubina
- A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, 28 Vavilova str., 119334, Moscow, Russia.
| | - Anton V Cherkasov
- Institute of Organometallic Chemistry of Russian Academy of Sciences, 49 Tropinina str., GSP-445, 630950, Nizhny Novgorod, Russia
| | - Saad Sene
- ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France.
| | - Ilya V Taydakov
- P. N. Lebedev Physical Institute of the Russian Academy of Sciences, Leninskiy Prospect 53, 119991, Moscow, Russia
- N. D. Zelinsky Institute of Organic Chemistry Russian Academy of Sciences, Leninsky Prospect, 47, 119991, Moscow, Russia
| | - Mikhail T Metlin
- P. N. Lebedev Physical Institute of the Russian Academy of Sciences, Leninskiy Prospect 53, 119991, Moscow, Russia
| | - Andrey A Tyutyunov
- A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, 28 Vavilova str., 119334, Moscow, Russia.
| | - Yannick Guari
- ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France.
| | | | - Alexander A Trifonov
- A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, 28 Vavilova str., 119334, Moscow, Russia.
- Institute of Organometallic Chemistry of Russian Academy of Sciences, 49 Tropinina str., GSP-445, 630950, Nizhny Novgorod, Russia
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8
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Liu D, Guo X, Zhang X, Al-Kahtani AA, Chibotaru LF. Building Molecular Nanomagnets by Encapsulating Lanthanide Ions in Boron Nitride Nanotubes: Ab Initio Investigation. Inorg Chem 2024; 63:3769-3780. [PMID: 38346334 DOI: 10.1021/acs.inorgchem.3c03930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Lanthanide-based single-ion magnets have attracted much interest due to their great potential for information storage at the level of one molecule. Among various strategies to enhance magnetization blocking in such complexes, the synthesis of axially symmetric compounds is regarded as the most promising. Here, we investigate theoretically the magnetization blocking of several lanthanide ions (Tb3+, Dy3+, Ho3+, Er3+, and Tm3+) encapsulated in highly symmetric zigzag boron nitride nanotubes (BNNTs) of different diameters with ab initio methodology. We found that Tb3+@(7,0)BNNT, Dy3+@(7,0)BNNT, and Tm3+@(5,0)BNNT are suitable SIM candidates, while the other investigated complexes from this series show no signs of magnetization blocking owing to a hard competition between contributions to the crystal field of the lanthanide ion from neighboring and more distant atoms of the nanotube.
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Affiliation(s)
- Dan Liu
- School of Sciences, Great Bay University, Dongguan 523000, China
- Great Bay Institute for Advanced Study, Dongguan 523000, China
- Institute of Flexible Electronics, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, Shaanxi 710072, China
| | - Xuefeng Guo
- Institute of Flexible Electronics, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, Shaanxi 710072, China
| | - Xiaoyong Zhang
- School of Sciences, Great Bay University, Dongguan 523000, China
- Great Bay Institute for Advanced Study, Dongguan 523000, China
| | - Abdullah A Al-Kahtani
- Chemistry Department, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Liviu F Chibotaru
- Theory of Nanomaterials Group, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Leuven B-3001, Belgium
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9
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Sergentu DC, Le Guennic B, Maurice R. The resolution of the weak-exchange limit made rigorous, simple and general in binuclear complexes. Phys Chem Chem Phys 2024; 26:6844-6861. [PMID: 38328993 DOI: 10.1039/d3cp04943d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
The correct interpretation of magnetic properties in the weak-exchange regime has remained a challenging task for several decades. In this regime, the effective exchange interaction between local spins is quite weak, of the same order of magnitude or smaller than the various anisotropic terms, which generates a complex set of levels characterized by spin mixing. Although the model multispin Hamiltonian in the absence of local orbital momentum, , is considered good enough to map the experimental energies at zero field and in the strong-exchange limit, theoretical works pointed out limitations of this simple model. This work revives the use of ĤMS from a new theoretical perspective, detailing point-by-point a strategy to correctly map the computational energies and wave functions onto ĤMS, thus validating it regardless of the exchange limit. We will distinguish two cases, based on experimentally characterized dicobalt(II) complexes from the literature. If centrosymmetry imposes alignment of the various rank-2 tensors constitutive of ĤMS in the first case, the absence of any symmetry element prevents such alignment in the second case. In such a context, the strategy provided herein becomes a powerful tool to rationalize the experimental magnetic data, since it is capable of fully and rigorously extracting the multispin model without any assumption on the orientation of its constitutive tensors. Furthermore, the strategy allows to question the use of the spin Hamiltonian approach by explicitly controlling the projection norms on the model space, which is showcased in the second complex where local orbital momentum could have occurred (distorted octahedra). Finally, previous theoretical data related to a known dinickel(II) complex is reinterpreted, clarifying initial wanderings regarding the weak exchange limit.
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Affiliation(s)
- Dumitru-Claudiu Sergentu
- Univ Rennes, CNRS ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, 35000 Rennes, France.
- Laboratorul RA-03 (RECENT AIR), Universitatea Alexandru Ioan Cuza din Iaşi, 700506 Iaşi, Romania
- Facultatea de Chimie, Universitatea Alexandru Ioan Cuza din Iaşi, 700506 Iaşi, Romania
| | - Boris Le Guennic
- Univ Rennes, CNRS ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, 35000 Rennes, France.
| | - Rémi Maurice
- Univ Rennes, CNRS ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, 35000 Rennes, France.
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10
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Yang W, Rosenkranz M, Velkos G, Ziegs F, Dubrovin V, Schiemenz S, Spree L, de Souza Barbosa MF, Guillemard C, Valvidares M, Büchner B, Liu F, Avdoshenko SM, Popov AA. Covalency versus magnetic axiality in Nd molecular magnets: Nd-photoluminescence, strong ligand-field, and unprecedented nephelauxetic effect in fullerenes NdM 2N@C 80 (M = Sc, Lu, Y). Chem Sci 2024; 15:2141-2157. [PMID: 38332818 PMCID: PMC10848757 DOI: 10.1039/d3sc05146c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 12/20/2023] [Indexed: 02/10/2024] Open
Abstract
Nd-based nitride clusterfullerenes NdM2N@C80 with rare-earth metals of different sizes (M = Sc, Y, Lu) were synthesized to elucidate the influence of the cluster composition, shape and internal strain on the structural and magnetic properties. Single crystal X-ray diffraction revealed a very short Nd-N bond length in NdSc2N@C80. For Lu and Y analogs, the further shortening of the Nd-N bond and pyramidalization of the NdM2N cluster are predicted by DFT calculations as a result of the increased cluster size and a strain caused by the limited size of the fullerene cage. The short distance between Nd and nitride ions leads to a very large ligand-field splitting of Nd3+ of 1100-1200 cm-1, while the variation of the NdM2N cluster composition and concomitant internal strain results in the noticeable modulation of the splitting, which could be directly assessed from the well-resolved fine structure in the Nd-based photoluminescence spectra of NdM2N@C80 clusterfullerenes. Photoluminescence measurements also revealed an unprecedentedly strong nephelauxetic effect, pointing to a high degree of covalency. The latter appears detrimental to the magnetic axiality despite the strong ligand field. As a result, the ground magnetic state has considerable transversal components of the pseudospin g-tensor, and the slow magnetic relaxation of NdSc2N@C80 could be observed by AC magnetometry only in the presence of a magnetic field. A combination of the well-resolved magneto-optical states and slow relaxation of magnetization suggests that Nd clusterfullerenes can be useful building blocks for magneto-photonic quantum technologies.
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Affiliation(s)
- Wei Yang
- Leibniz Institute for Solid State and Materials Research (IFW Dresden) 01069 Dresden Germany
| | - Marco Rosenkranz
- Leibniz Institute for Solid State and Materials Research (IFW Dresden) 01069 Dresden Germany
| | - Georgios Velkos
- Leibniz Institute for Solid State and Materials Research (IFW Dresden) 01069 Dresden Germany
| | - Frank Ziegs
- Leibniz Institute for Solid State and Materials Research (IFW Dresden) 01069 Dresden Germany
| | - Vasilii Dubrovin
- Leibniz Institute for Solid State and Materials Research (IFW Dresden) 01069 Dresden Germany
| | - Sandra Schiemenz
- Leibniz Institute for Solid State and Materials Research (IFW Dresden) 01069 Dresden Germany
| | - Lukas Spree
- Leibniz Institute for Solid State and Materials Research (IFW Dresden) 01069 Dresden Germany
- Center for Quantum Nanoscience, Institute for Basic Science (IBS) Seoul Republic of Korea
| | | | | | | | - Bernd Büchner
- Leibniz Institute for Solid State and Materials Research (IFW Dresden) 01069 Dresden Germany
| | - Fupin Liu
- Leibniz Institute for Solid State and Materials Research (IFW Dresden) 01069 Dresden Germany
| | - Stanislav M Avdoshenko
- Leibniz Institute for Solid State and Materials Research (IFW Dresden) 01069 Dresden Germany
| | - Alexey A Popov
- Leibniz Institute for Solid State and Materials Research (IFW Dresden) 01069 Dresden Germany
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11
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Panja A, Paul S, Moreno-Pineda E, Herchel R, Jana NC, Brandão P, Novitchi G, Wernsdorfer W. Insight into ferromagnetic interactions in Cu II-Ln III dimers with a compartmental ligand. Dalton Trans 2024; 53:2501-2511. [PMID: 38205580 PMCID: PMC10845014 DOI: 10.1039/d3dt03557c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 12/27/2023] [Indexed: 01/12/2024]
Abstract
In the last two decades, efforts have been devoted to obtaining insight into the magnetic interactions between CuII and LnIII utilizing experimental and theoretical means. Experimentally, it has been observed that the exchange coupling (J) in CuII-LnIII systems is often found to be ferromagnetic for ≥4f7 metal ions. However, exchange interactions at sub-Kelvin temperatures between CuII and the anisotropic/isotropic LnIII ions are not often explored. In this report, we have synthesized a series of heterobimetallic [CuLn(HL)(μ-piv)(piv)2] complexes (LnIII = Gd (1), Tb (2), Dy (3) and Er (4)) from a new compartmental Schiff base ligand, N,N'-bis(3-methoxy-5-methylsalicylidene)-1,3-diamino-2-propanol (H3L). X-ray crystallographic analysis reveals that all four complexes are isostructural and isomorphous. Magnetic susceptibility measurements reveal a ferromagnetic coupling between the CuII ion and its respective LnIII ion for all the complexes, as often observed. Moreover, μ-SQUID studies, at sub-Kelvin temperatures, show S-shaped hysteresis loops indicating the presence of antiferromagnetic coupling in complexes 1-3. The antiferromagnetic interaction is explained by considering the shortest Cu⋯Cu distance in the crystal structure. The nearly closed loops for 1-3 highlight their fast relaxation characteristics, while the opened loops for 4 might arise from intermolecular ordering. CASSCF calculations allow the quantitative assessment of the interactions, which are further supported by BS-DFT calculations.
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Affiliation(s)
- Anangamohan Panja
- Department of Chemistry, Gokhale Memorial Girls' College, 1/1 Harish Mukherjee Road, Kolkata-700020, India.
- Department of Chemistry, Panskura Banamali College, Panskura RS, WB 721152, India
| | - Sagar Paul
- Physikalisches Institut, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany.
| | - Eufemio Moreno-Pineda
- Universidad de Panamá, Facultad de Ciencias Naturales, Exactas y Tecnología, Depto. de Química-Física, 0824 Panamá, Panama
- Universidad de Panamá, Facultad de Ciencias Naturales, Exactas y Tecnología, Grupo de Investigación de Materiales, 0824 Panamá, Panama
| | - Radovan Herchel
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 77146 Olomouc, Czech Republic
| | - Narayan Ch Jana
- Department of Chemistry, Panskura Banamali College, Panskura RS, WB 721152, India
| | - Paula Brandão
- Department of Chemistry, CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Ghenadie Novitchi
- Laboratoire National des Champs Magnétiques Intenses, UPR CNRS 3228, Université Grenoble-Alpes, B.P. 166, 38042 Grenoble Cedex 9, France
| | - Wolfgang Wernsdorfer
- Physikalisches Institut, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany.
- Institute for Quantum Materials and Technology (IQMT), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen D-76344, Germany
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12
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Sánchez-Lara E, Favela R, Tzian K, Monroy-Torres B, Romo-Pérez A, Ramírez-Apan MT, Flores-Alamo M, Rodríguez-Diéguez A, Cepeda J, Castillo I. Effects of the tetravanadate [V 4O 12] 4- anion on the structural, magnetic, and biological properties of copper/phenanthroline complexes. J Biol Inorg Chem 2024; 29:139-158. [PMID: 38175299 PMCID: PMC11001746 DOI: 10.1007/s00775-023-02035-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 10/30/2023] [Indexed: 01/05/2024]
Abstract
The aim to access linked tetravanadate [V4O12]4- anion with mixed copper(II) complexes, using α-amino acids and phenanthroline-derived ligands, resulted in the formation of four copper(II) complexes [Cu(dmb)(Gly)(OH2)]2[Cu(dmb)(Gly)]2[V4O12]·9H2O (1) [Cu(dmb)(Lys)]2[V4O12]·8H2O (2), [Cu(dmp)2][V4O12]·C2H5OH·11H2O (3), and [Cu(dmp)(Gly)Cl]·2H2O (4), where dmb = 4,4'-dimethioxy-2,2'-bipyridine; Gly = glycine; Lys = lysine; and dmp = 2,9-dimethyl-1,10-phenanthroline. The [V4O12]4- anion is functionalized with mixed copper(II) units in 1 and 2; while in 3, it acts as a counterion of two [Cu(dmp)]2+ units. Compound 4 crystallized as a unit that did not incorporate the vanadium cluster. All compounds present magnetic couplings arising from Cu⋯O/Cu⋯Cu bridges. Stability studies of water-soluble 3 and 4 by UV-Vis spectroscopy in cell culture medium confirmed the robustness of 3, while 4 appears to undergo ligand scrambling over time, resulting partially in the stable species [Cu(dmp)2]+ that was also identified by electrospray ionization mass spectrometry at m/z = 479. The in vitro cytotoxicity activity of 3 and 4 was determined in six cancer cell lines; the healthy cell line COS-7 was also included for comparative purposes. MCF-7 cells were more sensitive to compound 3 with an IC50 value of 12 ± 1.2 nmol. The tested compounds did not show lipid peroxidation in the TBARS assay, ruling out a mechanism of action via reactive oxygen species formation. Both compounds inhibited cell migration at 5 µM in wound-healing assays using MCF-7, PC-3, and SKLU-1 cell lines, opening a new window to study the anti-metastatic effect of mixed vanadium-copper(II) systems.
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Affiliation(s)
- Eduardo Sánchez-Lara
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Interior, CU, 04510, Ciudad de Mexico, Mexico.
| | - Roberto Favela
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Interior, CU, 04510, Ciudad de Mexico, Mexico
| | - Kitze Tzian
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Interior, CU, 04510, Ciudad de Mexico, Mexico
| | - Brian Monroy-Torres
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Interior, CU, 04510, Ciudad de Mexico, Mexico
| | - Adriana Romo-Pérez
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Interior, CU, 04510, Ciudad de Mexico, Mexico
| | - María Teresa Ramírez-Apan
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Interior, CU, 04510, Ciudad de Mexico, Mexico
| | - Marcos Flores-Alamo
- Facultad de Química, Universidad Nacional Autónoma de México, Circuito Exterior, CU, 04510, Ciudad de Mexico, Mexico
| | - Antonio Rodríguez-Diéguez
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, Avda. Fuentenueva, 18071, Granada, Spain
| | - Javier Cepeda
- Departamento de Química Aplicada, Facultad de Química, Universidad del País Vasco UPV/EHU, 20018, Donostia-San Sebastian, Spain
| | - Ivan Castillo
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Interior, CU, 04510, Ciudad de Mexico, Mexico.
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13
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Mariano L, Mondal S, Lunghi A. Spin-Vibronic Dynamics in Open-Shell Systems beyond the Spin Hamiltonian Formalism. J Chem Theory Comput 2024; 20:323-332. [PMID: 38153836 PMCID: PMC10782446 DOI: 10.1021/acs.jctc.3c01130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 12/05/2023] [Accepted: 12/05/2023] [Indexed: 12/30/2023]
Abstract
Vibronic coupling has a dramatic influence over a large number of molecular processes, ranging from photochemistry to spin relaxation and electronic transport. The simulation of vibronic coupling with multireference wave function methods has been largely applied to organic compounds, and only early efforts are available for open-shell systems such as transition metal and lanthanide complexes. In this work, we derive a numerical strategy to differentiate the molecular electronic Hamiltonian in the context of multireference ab initio methods and inclusive of spin-orbit coupling effects. We then provide a formulation of open quantum system dynamics able to predict the time evolution of the electron density matrix under the influence of a Markovian phonon bath up to fourth-order perturbation theory. We apply our method to Co(II) and Dy(III) molecular complexes exhibiting long spin relaxation times and successfully validate our strategy against the use of an effective spin Hamiltonian. Our study sheds light on the nature of vibronic coupling, the importance of electronic excited states in spin relaxation, and the need for high-level computational chemistry to quantify it.
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Affiliation(s)
- Lorenzo
A. Mariano
- School of Physics, AMBER and CRANN
Institute, Trinity College, Dublin 2, Ireland
| | - Sourav Mondal
- School of Physics, AMBER and CRANN
Institute, Trinity College, Dublin 2, Ireland
| | - Alessandro Lunghi
- School of Physics, AMBER and CRANN
Institute, Trinity College, Dublin 2, Ireland
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14
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Manvell AS, Pfleger R, Bonde NA, Briganti M, Mattei CA, Nannestad TB, Weihe H, Powell AK, Ollivier J, Bendix J, Perfetti M. LnDOTA puppeteering: removing the water molecule and imposing tetragonal symmetry. Chem Sci 2023; 15:113-123. [PMID: 38131074 PMCID: PMC10732010 DOI: 10.1039/d3sc03928e] [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: 07/29/2023] [Accepted: 10/25/2023] [Indexed: 12/23/2023] Open
Abstract
Complexes of lanthanide(iii) ions (Ln) with tetraazacyclododecane-N,N',N'',N'''-tetraacetate (DOTA) are a benchmark in the field of magnetism due to their well-investigated and sometimes surprising features. Ab initio calculations suggest that the ninth ligand, an axial water molecule, is key in defining the magnetic properties because it breaks the potential C4 symmetry of the resulting complexes. In this paper, we experimentally isolate the role of the water molecule by excluding it from the metal coordination sphere without altering the chemical structure of the ligand. Our complexes are therefore designed to be geometrically tetragonal and strict crystallographic symmetry is achieved by exploiting a combination of solution ionic strength and solid state packing effects. A thorough multitechnique approach has been used to unravel the electronic structure and magnetic anisotropy of the complexes. Moreover, the geometry enhancement allows us to predict, using only one angle obtained from the crystal structure, the ground state composition of all the studied derivatives (Ln = Tb to Yb). Therefore, these systems also provide an excellent platform to test the validity and limitations of the ab initio methods. Our combined experimental and theoretical investigation proves that the water molecule is indeed key in defining the magnetic anisotropy and the slow relaxation of these complexes.
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Affiliation(s)
- Anna Schannong Manvell
- Department of Chemistry, University of Copenhagen Universitetsparken 5 DK-2100 Copenhagen Denmark
| | - Rouven Pfleger
- Department of Chemistry, University of Copenhagen Universitetsparken 5 DK-2100 Copenhagen Denmark
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology Engesserstrasse 15 76131 Karlsruhe Germany
| | - Niels Andreas Bonde
- Department of Chemistry, University of Copenhagen Universitetsparken 5 DK-2100 Copenhagen Denmark
- Institut Laue-Langevin 71 avenue des Martyrs, CS 20156 38042 Grenoble Cedex 9 France
| | - Matteo Briganti
- Department of Chemistry U. Schiff Via della Lastruccia 3 50019 Sesto Fiorentino Italy
| | - Carlo Andrea Mattei
- Department of Chemistry U. Schiff Via della Lastruccia 3 50019 Sesto Fiorentino Italy
| | - Theis Brock Nannestad
- Department of Chemistry, University of Copenhagen Universitetsparken 5 DK-2100 Copenhagen Denmark
| | - Høgni Weihe
- Department of Chemistry, University of Copenhagen Universitetsparken 5 DK-2100 Copenhagen Denmark
| | - Annie K Powell
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology Engesserstrasse 15 76131 Karlsruhe Germany
| | - Jacques Ollivier
- Institut Laue-Langevin 71 avenue des Martyrs, CS 20156 38042 Grenoble Cedex 9 France
| | - Jesper Bendix
- Department of Chemistry, University of Copenhagen Universitetsparken 5 DK-2100 Copenhagen Denmark
| | - Mauro Perfetti
- Department of Chemistry U. Schiff Via della Lastruccia 3 50019 Sesto Fiorentino Italy
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15
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Lukens WW, Minasian SG, Booth CH. Strengths of covalent bonds in LnO 2 determined from O K-edge XANES spectra using a Hubbard model. Chem Sci 2023; 14:12784-12795. [PMID: 38020387 PMCID: PMC10646950 DOI: 10.1039/d3sc03304j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 10/25/2023] [Indexed: 12/01/2023] Open
Abstract
In LnO2 (Ln = Ce, Pr, and Tb), the amount of Ln 4f mixing with O 2p orbitals was determined by O K-edge X-ray absorption near edge (XANES) spectroscopy and was similar to the amount of mixing between the Ln 5d and O 2p orbitals. This similarity was unexpected since the 4f orbitals are generally perceived to be "core-like" and can only weakly stabilize ligand orbitals through covalent interactions. While the degree of orbital mixing seems incompatible with this view, orbital mixing alone does not determine the degree of stabilization provided by a covalent interaction. We used a Hubbard model to determine this stabilization from the energies of the O 2p to 4f, 5d(eg), and 5d(t2g) excited charge-transfer states and the amount of excited state character mixed into the ground state, which was determined using Ln L3-edge and O K-edge XANES spectroscopy. The largest amount of stabilization due to mixing between the Ln 4f and O 2p orbitals was 1.6(1) eV in CeO2. While this energy is substantial, the stabilization provided by mixing between the Ln 5d and O 2p orbitals was an order of magnitude greater consistent with the perception that covalent bonding in the lanthanides is largely driven by the 5d orbitals rather than the 4f orbitals.
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Affiliation(s)
- Wayne W Lukens
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley CA 94720 USA
| | - Stefan G Minasian
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley CA 94720 USA
| | - Corwin H Booth
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley CA 94720 USA
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16
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Nabi R, Staab JK, Mattioni A, Kragskow JGC, Reta D, Skelton JM, Chilton NF. Accurate and Efficient Spin-Phonon Coupling and Spin Dynamics Calculations for Molecular Solids. J Am Chem Soc 2023; 145. [PMID: 37917936 PMCID: PMC10655086 DOI: 10.1021/jacs.3c06015] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 10/16/2023] [Accepted: 10/18/2023] [Indexed: 11/04/2023]
Abstract
Molecular materials are poised to play a significant role in the development of future optoelectronic and quantum technologies. A crucial aspect of these areas is the role of spin-phonon coupling and how it facilitates energy transfer processes such as intersystem crossing, quantum decoherence, and magnetic relaxation. Thus, it is of significant interest to be able to accurately calculate the molecular spin-phonon coupling and spin dynamics in the condensed phase. Here, we demonstrate the maturity of ab initio methods for calculating spin-phonon coupling by performing a case study on a single-molecule magnet and showing quantitative agreement with the experiment, allowing us to explore the underlying origins of its spin dynamics. This feat is achieved by leveraging our recent developments in analytic spin-phonon coupling calculations in conjunction with a new method for including the infinite electrostatic potential in the calculations. Furthermore, we make the first ab initio determination of phonon lifetimes and line widths for a molecular magnet to prove that the commonplace Born-Markov assumption for the spin dynamics is valid, but such "exact" phonon line widths are not essential to obtain accurate magnetic relaxation rates. Calculations using this approach are facilitated by the open-source packages we have developed, enabling cost-effective and accurate spin-phonon coupling calculations on molecular solids.
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Affiliation(s)
- Rizwan Nabi
- Department
of Chemistry, University of Manchester, Manchester M13 9PL, U.K.
| | - Jakob K. Staab
- Department
of Chemistry, University of Manchester, Manchester M13 9PL, U.K.
| | - Andrea Mattioni
- Department
of Chemistry, University of Manchester, Manchester M13 9PL, U.K.
| | - Jon G. C. Kragskow
- Department
of Chemistry, University of Manchester, Manchester M13 9PL, U.K.
- Department
of Chemistry, University of Bath, Bath BA2 7AY, U.K.
| | - Daniel Reta
- Department
of Chemistry, University of Manchester, Manchester M13 9PL, U.K.
- Faculty
of Chemistry, University of the Basque Country
UPV/EHU, 20018 Donostia, Spain
- Donostia
International Physics Center (DIPC), 20018 Donostia, Spain
- IKERBASQUE,
Basque Foundation for Science, 48013 Bilbao, Spain
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17
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Tarannum I, Moorthy S, Singh SK. Understanding electrostatics and covalency effects in highly anisotropic organometallic sandwich dysprosium complexes [Dy(C mR m) 2] (where R = H, SiH 3, CH 3 and m = 4 to 9): a computational perspective. Dalton Trans 2023; 52:15576-15589. [PMID: 37786345 DOI: 10.1039/d3dt01646c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
In this article, we have thoroughly studied the electronic structure and 4f-ligand covalency of six mononuclear dysprosium organometallic sandwich complexes [Dy(CmRm)2]n+/- (where R = H, SiH3, CH3; m = 4 to 9; n = 1, 3) using both the scalar relativistic density functional and complete active space self-consistent field (CASSCF) and N-electron valence perturbation theory (NEVPT2) method to shed light on the ligand field effects in fine-tuning the magnetic anisotropy of these complexes. Energy decomposition analysis (EDA) and ab initio-based ligand field theory AILFT calculations predict the sizable 4f-ligand covalency in all these complexes. The analysis of CASSCF/NEVPT2 computed spin-Hamiltonian (SH) parameters indicates the stabilization of mJ |±15/2〉 for [Dy(C4(SiH3)4)2]- (1), [Dy(C5(CH3)5)2]+ (2) and [Dy(C6H6)2]3+ (3) complexes with the Ucal value of 1867.5, 1621.5 and 1070.8 cm-1, respectively. On the other hand, we observed mJ |±9/2〉 as the ground state for [Dy(C7H7)2]3- (4) and [Dy(C8H8)2]- (5) complexes with significantly smaller Ucal values of 237.1 and 38.6 cm-1 respectively. For the nine-membered ring [Dy(C9H9)2]+ (6) complex, we observed the stabilization of the mJ |±1/2〉 ground state, with the first excited state being located ∼29 cm-1 higher in energy. AILFT-NEVPT2 ligand field splitting analysis indicates that the presence of π-type 4f-ligand interactions in complexes 1-3 help generate the axial-ligand field, while the δ-type interactions in complexes 4-5 generate the equatorial ligand field despite the ligands approaching from the axial direction. As the ring size increases, φ-type interactions dominate, generating a pure equatorial ligand field stabilising mJ |±1/2〉 as the ground state for 6. Calculations suggest that the nature of the ligand field mainly governs the Ucal values in the following order: 4f-Lσ > 4f-Lπ > 4f-Lδ > 4f-Lφ. Calculations were performed by replacing ligands with CHELPG charges to access the crystal field (CF) effects which suggests the stabilization of pure mJ |±15/2〉 in all the charge-embedded models (1Q-6Q). Our findings point out that the crystal field and ligand field effects complement each other and generate a giant barrier for magnetic relaxation in the small ring complexes 1-3, while a relatively weak crystal field and adverse 4f-Lδ/4f-Lφ interactions diminish the SMM behaviour in the large ring complexes 4-6.
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Affiliation(s)
- Ibtesham Tarannum
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana, 502285, India.
| | - Shruti Moorthy
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana, 502285, India.
| | - Saurabh Kumar Singh
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana, 502285, India.
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18
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Islam MA, Berthon C, Jung J, Bolvin H. Bonding and Magnetic Trends in the [An III(DPA) 3] 3- Series Compared to the Ln(III) and An(IV) Analogues. Inorg Chem 2023; 62:17254-17264. [PMID: 37818639 DOI: 10.1021/acs.inorgchem.3c02482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/12/2023]
Abstract
The crystal field parameters are determined from first-principles calculations in the [AnIII(DPA)3]3- series, completing previous work on the [LnIII(DPA)3]3- and [AnIV(DPA)3]2- series. The crystal field strength parameter follows the Ln(III) < An(III) < An(IV) trend. The parameters deduced at the orbital level decrease along the series, while J-mixing strongly impacts the many-electron parameters, especially for the Pu(III) complex. We further compile the available data for the three series. In some aspects, An(III) complexes are closer to Ln(III) than to An(IV) complexes with regard to the geometrical structure and bonding descriptors. At the beginning of the series, up to Pu(III), there is a quantitative departure from the free ion, especially for the Pa(III) complex. The magnetic properties of the actinides keep the trends of the lanthanides; in particular, the axial magnetic susceptibility follows Bleaney's theory qualitatively.
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Affiliation(s)
- Md Ashraful Islam
- Laboratoire de Chimie et Physique Quantiques, CNRS, Université Toulouse III, 118 Route de Narbonne, 31062 Toulouse, France
| | - Claude Berthon
- CEA, DES, ISEC, DMRC, Univ Montpellier, Marcoule, 30207 Bagnols-sur-Cèze, France
| | - Julie Jung
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Hélène Bolvin
- Laboratoire de Chimie et Physique Quantiques, CNRS, Université Toulouse III, 118 Route de Narbonne, 31062 Toulouse, France
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19
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Ghosh R, Sarkar S, Jana Y, Piwowarska D, Gnutek P, Rudowicz C. Eu 3+ ions as a crystal-field probe for low-symmetry sites in doped phosphors - a case study: Eu 3+ at triclinic sites in Li 6RE(BO 3) 3 (RE = Y, Gd), YBO 3 and ZnO and at trigonal sites in YAl 3(BO 3) 4. Phys Chem Chem Phys 2023; 25:25537-25551. [PMID: 37712933 DOI: 10.1039/d3cp03090c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/16/2023]
Abstract
We present crystal-field (CF) calculations of energy levels (Ei) of Eu3+ ions doped in various hosts aimed at exploring the low-symmetry properties of CF parameters (CFPs) and reliability of CFP modelling with decreasing site symmetry. The hosts studied are: Li6Y(BO3)3, Li6Gd(BO3)3, YBO3, and ZnO with Eu3+ at triclinic sites; YAl3(BO3)4 with Eu3+ ions at trigonal D3 symmetry. Two independent CFP modelling approaches utilizing the hosts' structural data are employed: the exchange charge model (ECM) and the superposition model (SPM). We adopt the Eu3+ actual site symmetry and not the approximated one. The Ei values calculated using CFPs modelled by the ECM and SPM mutually agree with the observed ones. For triclinic symmetry, the ECM/CFPs and SPM/CFPs were numerically distinct, yet turned out to be physically equivalent yielding identical rotational invariants, Sk (k = 2, 4, 6) and Ei. For trigonal symmetry, both CFP sets agree numerically, thus Sk and Ei are identical. This disparity poses a dilemma, since the modified crystallographic axis system was used in both approaches. The standardization of the triclinic CFPs using the 3DD package was performed to solve this dilemma. It has enabled discussing standardization aspects in experimental and computed CFP sets and elucidating intricate low-symmetry aspects inherent in CFP sets. Understanding of low-symmetry aspects in CF studies may bring about a better interpretation of the spectroscopic and magnetic properties of rare-earth ion doped host crystals. Thus, our study could provide more deep insights into the importance of clear definitions of axis systems and adequate treatment of actual site symmetry in the modelling of CFPs for low-symmetry cases which is essential for technological applications and engineering of rare-earth activated phosphor materials.
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Affiliation(s)
- Riti Ghosh
- Department of Physics, University of Kalyani, Kalyani-741235, Nadia, WB, India.
| | - Shankhanil Sarkar
- Department of Physics, University of Kalyani, Kalyani-741235, Nadia, WB, India.
| | - Yatramohan Jana
- Department of Physics, University of Kalyani, Kalyani-741235, Nadia, WB, India.
| | - Danuta Piwowarska
- Department of Technical Physics, Faculty of Mechanical Engineering and Mechatronics, West Pomeranian University of Technology in Szczecin, 70-311 Szczecin, Poland
| | - Paweł Gnutek
- Laboratory for Research on Structure and Mechanical Properties of Materials POLITEST, Faculty of Mechanical Engineering and Mechatronics, West Pomeranian University of Technology in Szczecin, 70-311 Szczecin, Poland
| | - Czesław Rudowicz
- Faculty of Chemistry, Adam Mickiewicz University, 61-614 Poznań, Poland.
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20
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Marcinkowski D, Kubicki M, Patroniak V, Muzioł T, Chorazy S, Shi L, Zychowicz M, Majcher-Fitas AM, Podgajny R, Gorczyński A. Trityl-Based Lanthanide-Supramolecular Assemblies Exhibiting Slow Magnetic Relaxation. Chemistry 2023; 29:e202300695. [PMID: 37408381 DOI: 10.1002/chem.202300695] [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: 03/03/2023] [Revised: 06/26/2023] [Accepted: 07/03/2023] [Indexed: 07/07/2023]
Abstract
The triphenylmethane (trityl) group has been recognized as a supramolecular synthon in crystal engineering, molecular machine rotors and stereochemical chirality inductors in materials science. Herein we demonstrate for the first time how it can be utilized in the domain of molecular magnetic materials through shaping of single molecule magnet (SMM) properties within the lanthanide complexes in tandem with other non-covalent interactions. Trityl-appended mono- (HL1 ) and bis-compartmental (HL2 ) hydrazone ligands were synthesized and complexated with Dy(III) and Er(III) triflate and nitrate salts to generate four monometallic (1-4) and two bimetallic (5, 6) complexes. The static and dynamic magnetic properties of 1-6 were investigated, revealing that only ligand HL1 induces assemblies (1-4) capable of showing SMM behaviour, with Dy(III) congeners (1, 2) able to exhibit the phenomenon also under zero field conditions. Theoretical ab initio studies helped in determination of Dy(III) energetic levels, magnetic anisotropic axes and corroborated magnetic relaxation mechanisms to be a combination of Raman and quantum tunnelling in zero dc field, the latter being cancelled in the optimum non-zero dc field. Our work represents the first study of magneto-structural correlations within the trityl Ln-SMMs, leading to generation of slowly relaxing zero-field dysprosium complexes within the hydrogen-bonded assemblies.
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Affiliation(s)
- Dawid Marcinkowski
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614, Poznań, Poland
| | - Maciej Kubicki
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614, Poznań, Poland
| | - Violetta Patroniak
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614, Poznań, Poland
| | - Tadeusz Muzioł
- Nicolaus Copernicus University in Torun, Faculty of Chemistry, Jurija Gagarina 11, 87-100, Toruń, Poland
| | - Szymon Chorazy
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
| | - Le Shi
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
| | - Mikołaj Zychowicz
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
| | - Anna M Majcher-Fitas
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Łojasiewicza 11, 30-348, Kraków, Poland
| | - Robert Podgajny
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
| | - Adam Gorczyński
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614, Poznań, Poland
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21
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Zanella S, Aragon-Alberti M, Brite CDS, Salles F, Carlos LD, Long J. Luminescent Single-Molecule Magnets as Dual Magneto-Optical Molecular Thermometers. Angew Chem Int Ed Engl 2023; 62:e202306970. [PMID: 37418512 DOI: 10.1002/anie.202306970] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/30/2023] [Accepted: 07/03/2023] [Indexed: 07/09/2023]
Abstract
Luminescent thermometry allows the remote detection of the temperature and holds great potential in future technological applications in which conventional systems could not operate. Complementary approaches to measuring the temperature aiming to enhance the thermal sensitivity would however represent a decisive step forward. For the first time, we demonstrate the proof-of-concept that luminescence thermometry could be associated with a complementary temperature readout related to a different property. Namely, we propose to take advantage of the temperature dependence of both magnetic (canonical susceptibility and relaxation time) and luminescence features (emission intensity) found in Single-Molecule Magnets (SMM) to develop original dual magneto-optical molecular thermometers to conciliate high-performance SMM and Boltzmann-type luminescence thermometry. We highlight this integrative approach to concurrent luminescent and magnetic thermometry using an air-stable benchmark SMM [Dy(bbpen)Cl] (H2 bbpen=N,N'-bis(2-hydroxybenzyl)-N,N'-bis(2-methylpyridyl)ethyl-enediamine)) exhibiting Dy3+ luminescence. The synergy between multiparametric magneto-optical readouts and multiple linear regression makes possible a 10-fold improvement in the relative thermal sensitivity of the thermometer over the whole temperature range, compared with the values obtained with the single optical or magnetic devices.
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Affiliation(s)
- Sofia Zanella
- Phantom-g, CICECO-Aveiro Institute of Materials, Physics Department, University of Aveiro, 3810-193, Aveiro, Portugal
| | | | - Carlos D S Brite
- Phantom-g, CICECO-Aveiro Institute of Materials, Physics Department, University of Aveiro, 3810-193, Aveiro, Portugal
| | - Fabrice Salles
- ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France
| | - Luís D Carlos
- Phantom-g, CICECO-Aveiro Institute of Materials, Physics Department, University of Aveiro, 3810-193, Aveiro, Portugal
| | - Jérôme Long
- ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France
- Institut Universitaire de France, (IUF), 1 rue Descartes, 75231, Paris Cedex 05, France
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22
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Kragskow JGC, Mattioni A, Staab JK, Reta D, Skelton JM, Chilton NF. Spin-phonon coupling and magnetic relaxation in single-molecule magnets. Chem Soc Rev 2023; 52:4567-4585. [PMID: 37377351 PMCID: PMC10351214 DOI: 10.1039/d2cs00705c] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Indexed: 06/29/2023]
Abstract
Electron-phonon coupling is important in many physical phenomena, e.g. photosynthesis, catalysis and quantum information processing, but its impacts are difficult to grasp on the microscopic level. One area attracting wide interest is that of single-molecule magnets, which is motivated by searching for the ultimate limit in the miniaturisation of binary data storage media. The utility of a molecule to store magnetic information is quantified by the timescale of its magnetic reversal processes, also known as magnetic relaxation, which is limited by spin-phonon coupling. Several recent accomplishments of synthetic organometallic chemistry have led to the observation of molecular magnetic memory effects at temperatures above that of liquid nitrogen. These discoveries have highlighted how far chemical design strategies for maximising magnetic anisotropy have come, but have also highlighted the need to characterise the complex interplay between phonons and molecular spin states. The crucial step is to make a link between magnetic relaxation and chemical motifs, and so be able to produce design criteria to extend molecular magnetic memory. The basic physics associated with spin-phonon coupling and magnetic relaxation was outlined in the early 20th century using perturbation theory, and has more recently been recast in the form of a general open quantum systems formalism and tackled with different levels of approximations. It is the purpose of this Tutorial Review to introduce the topics of phonons, molecular spin-phonon coupling, and magnetic relaxation, and to outline the relevant theories in connection with both the traditional perturbative texts and the more modern open quantum systems methods.
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Affiliation(s)
- Jon G C Kragskow
- Department of Chemistry, The University of Manchester, Manchester, M13 9PL, UK.
| | - Andrea Mattioni
- Department of Chemistry, The University of Manchester, Manchester, M13 9PL, UK.
| | - Jakob K Staab
- Department of Chemistry, The University of Manchester, Manchester, M13 9PL, UK.
| | - Daniel Reta
- Department of Chemistry, The University of Manchester, Manchester, M13 9PL, UK.
- Faculty of Chemistry, The University of the Basque Country UPV/EHU, Donostia, 20018, Spain
- Donostia International Physics Center (DIPC), Donostia, 20018, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, 48013, Spain
| | - Jonathan M Skelton
- Department of Chemistry, The University of Manchester, Manchester, M13 9PL, UK.
| | - Nicholas F Chilton
- Department of Chemistry, The University of Manchester, Manchester, M13 9PL, UK.
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23
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Yang QQ, Wang YF, Wang YX, Tang MJ, Yin B. Ab initio prediction of key parameters and magneto-structural correlation of tetracoordinated lanthanide single-ion magnets. Phys Chem Chem Phys 2023. [PMID: 37401358 DOI: 10.1039/d3cp01766d] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2023]
Abstract
Single-molecule magnets (SMMs) have great potential in becoming revolutionary materials for micro-electronic devices. As one type of SMM and holding the performance record, lanthanide single-ion magnets (Ln-SIMs) stand at the forefront of the family. Lowering the coordination number (CN) is an important strategy to improve the performance of Ln-SIMs. Here, we report a theoretical study on a typical group of low-CN Ln-SIMs, i.e., tetracoordinated structures. Our results are consistent with those of experiments and they identify the same three best Ln-SIMs via a concise criterion, i.e., the co-existence of long τQTM and high Ueff. Compared to the record-holding dysprosocenium systems, the best SIMs here possess τQTM values that are shorter by several orders of magnitude and Ueff values that are lower by ∼1000 Kelvin (K). These are important reasons for the fact that the tetracoordinated Ln-SIMs are clearly inferior to dysprosocenium. A simple but intuitive crystal-field analysis leads to several routes to improve the performance of a given Ln-SIM, including compression of the axial bond length, widening the axial bond angle, elongation of the equatorial bond length and usage of weaker equatorial donor ligands. Although these routes are not brand-new, the most efficient option and the degree of improvement resulting from it are not known in advance. Consequently, a theoretical magneto-structural study, covering various routes, is carried out for the best Ln-SIM here and the most efficient route is shown to be widening the axial ∠O-Dy-O angle. The most optimistic case, having a ∠O-Dy-O of 180°, could have a τQTM (up to 103 s) and Ueff (∼2400 K) close to those of the record-holders. Subsequently, a blocking temperature (TB) of 64 K is predicted to be possible for it. A more practical case, with ∠O-Dy-O being 160°, could have a τQTM of up to 400 s, Ueff of around 2200 K and the possibility of a TB of 57 K. Although having an inherent precision limit, these predictions provide a guide to performance improvement, starting from an existing system.
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Affiliation(s)
- Qi-Qi Yang
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, Lab of Theoretical Molecular Magnetism (LTMM), College of Chemistry and Materials Science, Northwest University, Xi'an, 710127, P. R. China.
| | - Yu-Fei Wang
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, Lab of Theoretical Molecular Magnetism (LTMM), College of Chemistry and Materials Science, Northwest University, Xi'an, 710127, P. R. China.
| | - Yu-Xi Wang
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, Lab of Theoretical Molecular Magnetism (LTMM), College of Chemistry and Materials Science, Northwest University, Xi'an, 710127, P. R. China.
| | - Ming-Jing Tang
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, Lab of Theoretical Molecular Magnetism (LTMM), College of Chemistry and Materials Science, Northwest University, Xi'an, 710127, P. R. China.
| | - Bing Yin
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, Lab of Theoretical Molecular Magnetism (LTMM), College of Chemistry and Materials Science, Northwest University, Xi'an, 710127, P. R. China.
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24
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Price CGT, Mondal A, Durrant JP, Tang J, Layfield RA. Structural and Magnetization Dynamics of Borohydride-Bridged Rare-Earth Metallocenium Cations. Inorg Chem 2023. [PMID: 37314885 DOI: 10.1021/acs.inorgchem.3c01038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The structure and magnetic properties of the bimetallic borohydride-bridged dysprosocenium compound [{(η5-Cpttt)(η5-CpMe4t)Dy}2(μ:κ2:κ2-BH4)]+[B(C6F5)4]- ([3Dy][B(C6F5)4]) are reported along with the solution-phase dynamics of the isostructural yttrium and lutetium analogues (Cpttt is 1,2,4-tri(tert-butyl)cyclopentadienyl, CpMe4t is tetramethyl(tert-butyl)cyclopentadienyl). The synthesis of [3M][B(C6F5)4] was accomplished in the 2:1 stoichiometric reactions of [(η5-Cpttt)(η5-CpMe4t)Dy(BH4)] (2M) with [CPh3][B(C6F5)4], with the metallocenes 2M obtained from reactions of the half-sandwich complexes [(η5-Cpttt)M(BH4)2(THF)] (1M) (M = Y, Dy, Lu) with NaCpMe4t. Crystallographic studies show significant lengthening of the M···B distance on moving through the series 1M, 2M, and 3M, with essentially linear {M···B···M} bridges in 3M. Multinuclear NMR spectroscopy indicates restricted rotation of the Cpttt ligands in 3Y and 3Lu in solution. The single-molecule magnet (SMM) properties of [3M][B(C6F5)4] are characterized by Raman and Orbach processes, with an effective barrier of 533(18) cm-1 and relaxation via the second-excited Kramers doublet. Although quantum tunneling of the magnetization (QTM) was not observed for [3M][B(C6F5)4], it was, surprisingly, found in its magnetically dilute version, which has a very similar barrier of Ueff = 499(21) cm-1. Consistent with this observation, slightly wider openings of the magnetic hysteresis loop at 2 K are found for [3M][B(C6F5)4] but not for the diluted analogue. The dynamic magnetic properties of the dysprosium SMMs and the role of exchange interactions in 3Dy are interpreted with the aid of multireference ab initio calculations.
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Affiliation(s)
- Christopher G T Price
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QJ, U.K
| | - Arpan Mondal
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QJ, U.K
| | - James P Durrant
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QJ, U.K
| | - Jinkui Tang
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
| | - Richard A Layfield
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QJ, U.K
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25
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Taran G, Moreno-Pineda E, Schulze M, Bonet E, Ruben M, Wernsdorfer W. Direct determination of high-order transverse ligand field parameters via µSQUID-EPR in a Et 4N[ 160GdPc 2] SMM. Nat Commun 2023; 14:3361. [PMID: 37291099 DOI: 10.1038/s41467-023-39003-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 05/25/2023] [Indexed: 06/10/2023] Open
Abstract
The development of quantum technologies requires a thorough understanding of systems possessing quantum effects that can ultimately be manipulated. In the field of molecular magnetism, one of the main challenges is to measure high-order ligand field parameters, which play an essential role in the relaxation properties of SMMs. The development of highly advanced theoretical calculations has allowed the ab-initio determination of such parameters; however, currently, there is a lack of quantitative assessment of how good the ab-initio parameters are. In our quest for technologies that can allow the extraction of such elusive parameters, we develop an experimental technique that combines the EPR spectroscopy and µSQUID magnetometry. We demonstrate the power of the technique by performing EPR-µSQUID measurement of a magnetically diluted single crystal of Et4N[GdPc2], by sweeping the magnetic field and applying a range of multifrequency microwave pulses. As a result, we were able to directly determine the high-order ligand field parameters of the system, enabling us to test theoretical predictions made by state-of-the-art ab-initio methods.
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Affiliation(s)
- Gheorghe Taran
- Physikalisches Institut, Karlsruhe Institute of Technology, D-76131, Karlsruhe, Germany
| | - Eufemio Moreno-Pineda
- Depto. de Química-Física, Facultad de Ciencias Naturales, Exactas y Tecnología, Universidad de Panamá, Panamá, Panamá.
- Grupo de Investigación de Materiales, Facultad de Ciencias Naturales, Exactas y Tecnología, Universidad de Panamá, Panamá, Panamá.
| | - Michael Schulze
- Physikalisches Institut, Karlsruhe Institute of Technology, D-76131, Karlsruhe, Germany
| | - Edgar Bonet
- Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble, 38000, France
| | - Mario Ruben
- Centre Européen de Sciences Quantiques (CESQ) within the Institut de Science et d'Ingénierie Supramoléculaires (ISIS), 8 allée Gaspard Monge, BP 70028, 67083, Strasbourg Cedex, France.
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Plats 1, D-76344, Eggenstein-Leopoldshafen, Germany.
- Institute for Quantum Materials and Technology (IQMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, D-76344, Eggenstein-Leopoldshafen, Germany.
| | - Wolfgang Wernsdorfer
- Physikalisches Institut, Karlsruhe Institute of Technology, D-76131, Karlsruhe, Germany.
- Institute for Quantum Materials and Technology (IQMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, D-76344, Eggenstein-Leopoldshafen, Germany.
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26
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Slow Magnetic Relaxation and Modulated Photoluminescent Emission of Coordination Polymer Based on 3-Amino-4-hydroxybenzoate Zn and Co Metal Ions. Molecules 2023; 28:molecules28041846. [PMID: 36838833 PMCID: PMC9964557 DOI: 10.3390/molecules28041846] [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: 01/11/2023] [Revised: 01/31/2023] [Accepted: 02/01/2023] [Indexed: 02/18/2023] Open
Abstract
As a starting point, a new 3D porous framework with the {[CoL]·0.5DMF·H2O}n chemical formula (where L = 3-amino-4-hydroxybenzoate) is described. Its performance as a single molecule magnet was explored. The study of magnetic properties reveals that Co-MOF shows no frequency-fdependant alternating current (ac) signals under zero direct current (dc) magnetic field, whereas single-molecule magnet behaviour is achieved when CoII ions are diluted in a ZnII based matrix. Interestingly, this strategy renders a bifunctional [CoxZn1-xL]n material that is also characterized by a strong photoluminescent emitting capacity.
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27
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Atkin AM, Giansiracusa MJ, Calvello S, Rousset E, Gable RW, Phonsri W, Murray KS, Howard JK, Soncini A, Mole RA, Boskovic C. Inelastic Neutron Scattering Measurement of the Ground State Tunneling Gap in Tb and Ho Analogues of a Dy Field-Induced Single-Molecule Magnet. Inorg Chem 2023; 62:1141-1155. [PMID: 36630675 DOI: 10.1021/acs.inorgchem.2c03457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Recent advances in single-molecule magnet (SMM) research have placed great value on interpretation of inelastic neutron scattering (INS) data for rare earth (RE)-containing SMMs. Here, we present the synthesis of several rare earth complexes where combined magnetic and INS studies have been performed, supported by ab initio calculations. The reaction of rare earth nitrate salts with 2,2'-bipyridine (2,2'-bpy) and tetrahalocatecholate (X4Cat2-, X = Br, Cl) ligands in methanol (MeOH) afforded two new families of compounds [RE(2,2'-bpy)2(X4Cat)(X4CatH)(MeOH)] (X = Br and RE = Y, Eu, Gd, Tb, Dy, Ho, Yb for 1-RE; X = Cl and RE = Y, Tb, Dy, Ho, and Yb for 2-RE). Addition of triethylamine (Et3N) to the reaction mixture delivered Et3NH[RE(2,2'-bpy)2(Br4Cat)2] (3-RE, RE = Er and Yb). Interestingly, cerium behaves differently to the rest of the series, generating (2,2'-bpyH)2[Ce(Br4Cat)3(2,2'-bpy)] (4-Ce) with tetravalent Ce(IV) in contrast to the trivalent metal ions in 1-3. The static magnetic properties of 1-RE (RE = Gd, Tb, Dy and Ho) were investigated in conjunction with INS measurements on 1-Y, 1-Tb, and 1-Ho to probe their ground state properties and any crystal field excitations. To facilitate interpretation of the INS spectra and provide insight into the magnetic behavior, ab initio calculations were performed using the single-crystal X-ray diffraction structural data of 1-RE (RE = Tb, Dy and Ho). The ab initio calculations indicate ground doublets dominated by the maximal angular momentum projection states of Kramers type for 1-Dy and Ising type for 1-Tb and 1-Ho. Dynamic magnetic susceptibility measurements indicate that 1-Dy exhibits slow magnetic relaxation in the presence of a small applied magnetic field mainly through Raman pathways. Inelastic neutron scattering spectra exhibit distinct transitions corresponding to crystal field-induced tunneling gaps between the pseudo-doublet ground state components for 1-Tb and 1-Ho, which is one of the first direct experimental measurements with INS of such tunneling transitions in a molecular nanomagnet. The power of high-resolution INS is demonstrated with evidence of two distinct tunneling gaps measurable for the two crystallographically unique Tb coordination environments observed in the single crystal X-ray structure.
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Affiliation(s)
- Aiden M Atkin
- School of Chemistry, University of Melbourne, Parkville, Victoria3010, Australia
| | | | - Simone Calvello
- School of Chemistry, University of Melbourne, Parkville, Victoria3010, Australia.,Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC2232, Australia
| | - Elodie Rousset
- School of Chemistry, University of Melbourne, Parkville, Victoria3010, Australia
| | - Robert W Gable
- School of Chemistry, University of Melbourne, Parkville, Victoria3010, Australia
| | - Wasinee Phonsri
- School of Chemistry, Monash University, Clayton, Victoria3168, Australia
| | - Keith S Murray
- School of Chemistry, Monash University, Clayton, Victoria3168, Australia
| | - James K Howard
- Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC2232, Australia
| | - Alessandro Soncini
- School of Chemistry, University of Melbourne, Parkville, Victoria3010, Australia
| | - Richard A Mole
- Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC2232, Australia
| | - Colette Boskovic
- School of Chemistry, University of Melbourne, Parkville, Victoria3010, Australia
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28
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Ray D, Oakley MS, Sarkar A, Bai X, Gagliardi L. Theoretical Investigation of Single-Molecule-Magnet Behavior in Mononuclear Dysprosium and Californium Complexes. Inorg Chem 2023; 62:1649-1658. [PMID: 36652606 PMCID: PMC9890484 DOI: 10.1021/acs.inorgchem.2c04013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Early-actinide-based (U, Np, and Pu) single-molecule magnets (SMMs) have yet to show magnetic properties similar to those of highly anisotropic lanthanide-based ones. However, there are not many studies exploring the late-actinides (more than half-filled f shells) as potential candidates for SMM applications. We computationally explored the electronic structure and magnetic properties of a hypothetical Cf(III) complex isostructural to the experimentally synthesized Dy(dbm)3(bpy) complex (bpy = 2,2'-bipyridine; dbm = dibenzoylmethanoate) via multireference methods and compared them to those of the Dy(III) analogue. This study shows that the Cf(III) complex can behave as a SMM and has a greater magnetic susceptibility compared to other experimentally and computationally studied early-actinide-based (U, Np, and Pu) magnetic complexes. However, Cf spontaneously undergoes α-decay and converts to Cm. Thus, we also explored the isostructural Cm(III)-based complex. The computed magnetic susceptibility and g-tensor values show that the Cm(III) complex has poor SMM behavior in comparison to both the Dy(III) and Cf(III) complexes, suggesting that the performance of Cf(III)-based magnets may be affected by α-decay and can explain the poor performance of experimentally studied Cf(III)-based molecular magnets in the literature. Further, this study suggests that the ligand field is dominant in Cf(III), which helps to increase the magnetization blocking barrier by nearly 3 times that of its 4f congener.
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Affiliation(s)
- Debmalya Ray
- Department
of Chemistry, Chemical Theory Center, and Minnesota Supercomputing
Institute, University of Minnesota, Minneapolis, Minnesota55455, United States
| | - Meagan S. Oakley
- Department
of Chemistry, Chemical Theory Center, and Minnesota Supercomputing
Institute, University of Minnesota, Minneapolis, Minnesota55455, United States
| | - Arup Sarkar
- Department
of Chemistry, Pritzker School of Molecular Engineering, James Franck
Institute, Chicago Center for Theoretical Chemistry, The University of Chicago, Chicago, Illinois60637, United States
| | - Xiaojing Bai
- Department
of Chemistry, Chemical Theory Center, and Minnesota Supercomputing
Institute, University of Minnesota, Minneapolis, Minnesota55455, United States
| | - Laura Gagliardi
- Department
of Chemistry, Pritzker School of Molecular Engineering, James Franck
Institute, Chicago Center for Theoretical Chemistry, The University of Chicago, Chicago, Illinois60637, United States,
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29
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Vincent A, Whyatt YL, Chilton NF, Long JR. Strong Axiality in a Dysprosium(III) Bis(borolide) Complex Leads to Magnetic Blocking at 65 K. J Am Chem Soc 2023; 145:1572-1579. [PMID: 36629382 PMCID: PMC9923674 DOI: 10.1021/jacs.2c08568] [Citation(s) in RCA: 29] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Substituted dysprosocenium complexes of the type [Dy(CpR)2]+ exhibit slow magnetic relaxation at cryogenic temperatures and have emerged as top-performing single-molecule magnets. The remarkable properties of these compounds derive in part from the strong axial ligand field afforded by the cyclopentadiene anions, and the design of analogous compounds with even stronger ligand fields is one promising route toward identifying new single-molecule magnets that retain a magnetic memory at even higher temperatures. Here, we report the synthesis and characterization of a dysprosium bis(borolide) compound, [K(18-crown-6)][Dy(BC4Ph5)2] (1), featuring the dysprosocenate anion [Dy(BC4Ph5)2]- with a pseudoaxial coordination environment afforded by two dianionic pentaphenyl borolide ligands. Variable-field magnetization data reveal open magnetic hysteresis up to 66 K, establishing 1 as a top-performing single-molecule magnet among its dysprosocenium analogues. Ac magnetic susceptibility data indicate that 1 relaxes via an Orbach mechanism above ∼80 K with Ueff = 1500(100) cm-1 and τ0 = 10-12.0(9) s, whereas Raman relaxation and quantum tunneling of the magnetization dominate at lower temperatures. Compound 1 exhibits a 100 s blocking temperature of 65 K, among the highest reported for dysprosium-based single-molecule magnets. Ab initio spin dynamics calculations support the experimental Ueff and τ0 values and enable a quantitative comparison of the relaxation dynamics of 1 and two representative dysprosocenium cations, yielding additional insights into the impact of the crystal field splitting and vibronic coupling on the observed relaxation behavior. Importantly, compound 1 represents a step toward the development of alternatives to substituted dysprosocenium single-molecule magnets with increased axiality.
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Affiliation(s)
- Alexandre
H. Vincent
- Department
of Chemistry, University of California,
Berkeley, Berkeley, California94720, United States
| | - Yasmin L. Whyatt
- Department
of Chemistry, The University of Manchester, Oxford Road, ManchesterM13 9PL, U.K.
| | - Nicholas F. Chilton
- Department
of Chemistry, The University of Manchester, Oxford Road, ManchesterM13 9PL, U.K.,
| | - Jeffrey R. Long
- Department
of Chemistry, University of California,
Berkeley, Berkeley, California94720, United States,Department
of Chemical & Biomolecular Engineering, University of California, Berkeley, Berkeley, California94720, United States,Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California94720, United States,
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30
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Liu W. Perspective: Simultaneous treatment of relativity, correlation, and
QED. WIRES COMPUTATIONAL MOLECULAR SCIENCE 2022. [DOI: 10.1002/wcms.1652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Wenjian Liu
- Qingdao Institute for Theoretical and Computational Sciences, Institute of Frontier and Interdisciplinary Science Shandong University Qingdao Shandong China
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31
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Ying X, Zhu Z, Zhao C, Zhang YQ, Tang J. Five-Coordinated Dysprosium Single-Molecule Magnet Functionalized by the SMe Group. Inorg Chem 2022; 61:20547-20551. [DOI: 10.1021/acs.inorgchem.2c03375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Xu Ying
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
- University of Science and Technology of China, Hefei 230026, P. R. China
| | - Zhenhua Zhu
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Chen Zhao
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
- University of Science and Technology of China, Hefei 230026, 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
| | - Jinkui Tang
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
- University of Science and Technology of China, Hefei 230026, P. R. China
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32
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Staab JK, Chilton NF. Analytic Linear Vibronic Coupling Method for First-Principles Spin-Dynamics Calculations in Single-Molecule Magnets. J Chem Theory Comput 2022; 18:6588-6599. [PMID: 36269220 PMCID: PMC9648194 DOI: 10.1021/acs.jctc.2c00611] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Indexed: 11/28/2022]
Abstract
Accurate modeling of vibronically driven magnetic relaxation from ab initio calculations is of paramount importance to the design of next-generation single-molecule magnets (SMMs). Previous theoretical studies have been relying on numerical differentiation to obtain spin-phonon couplings in the form of derivatives of spin Hamiltonian parameters. In this work, we introduce a novel approach to obtain these derivatives fully analytically by combining the linear vibronic coupling (LVC) approach with analytic complete active space self-consistent field derivatives and nonadiabatic couplings computed at the equilibrium geometry with a single electronic structure calculation. We apply our analytic approach to the computation of Orbach and Raman relaxation rates for a bis-cyclobutadienyl Dy(III) sandwich complex in the frozen-solution phase, where the solution environment is modeled by electrostatic multipole expansions, and benchmark our findings against results obtained using conventional numerical derivatives and a fully electronic description of the whole system. We demonstrate that our LVC approach exhibits high accuracy over a wide range of coupling strengths and enables significant computational savings due to its analytic, "single-shot" nature. Evidently, this offers great potential for advancing the simulation of a wide range of vibronic coupling phenomena in magnetism and spectroscopy, ultimately aiding the design of high-performance SMMs. Considering different environmental representations, we find that a point charge model shows the best agreement with the reference calculation, including the full electronic environment, but note that the main source of discrepancies observed in the magnetic relaxation rates originates from the approximate equilibrium electronic structure computed using the electrostatic environment models rather than from the couplings.
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Affiliation(s)
- Jakob K. Staab
- Department of Chemistry, The
University of Manchester, Manchester M13 9PL, U.K.
| | - Nicholas F. Chilton
- Department of Chemistry, The
University of Manchester, Manchester M13 9PL, U.K.
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33
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Kapurwan S, Mondal A, Sahu PK, Konar S. Windmill-like Ln 4 Clusters [Ln = Tb(III) and Dy(III)] Bridged by [α-AsW 9O 33] 9– Unit Showing Zero-Field SMM Behavior: Experimental and Theoretical Investigation. Inorg Chem 2022; 61:17459-17468. [DOI: 10.1021/acs.inorgchem.2c02298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sandhya Kapurwan
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal462066Madhya Pradesh, India
| | - Arpan Mondal
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal462066Madhya Pradesh, India
| | - Pradip Kumar Sahu
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal462066Madhya Pradesh, India
| | - Sanjit Konar
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal462066Madhya Pradesh, India
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34
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Lunghi A, Sanvito S. Computational design of magnetic molecules and their environment using quantum chemistry, machine learning and multiscale simulations. Nat Rev Chem 2022; 6:761-781. [PMID: 37118096 DOI: 10.1038/s41570-022-00424-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/15/2022] [Indexed: 11/09/2022]
Abstract
Having served as a playground for fundamental studies on the physics of d and f electrons for almost a century, magnetic molecules are now becoming increasingly important for technological applications, such as magnetic resonance, data storage, spintronics and quantum information. All of these applications require the preservation and control of spins in time, an ability hampered by the interaction with the environment, namely with other spins, conduction electrons, molecular vibrations and electromagnetic fields. Thus, the design of a novel magnetic molecule with tailored properties is a formidable task, which does not only concern its electronic structures but also calls for a deep understanding of the interaction among all the degrees of freedom at play. This Review describes how state-of-the-art ab initio computational methods, combined with data-driven approaches to materials modelling, can be integrated into a fully multiscale strategy capable of defining design rules for magnetic molecules.
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35
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Khurana R, Ali ME. Single-Molecule Magnetism in Linear Fe(I) Complexes with Aufbau and Non-Aufbau Ground States. Inorg Chem 2022; 61:15335-15345. [PMID: 36129329 DOI: 10.1021/acs.inorgchem.2c00981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
With the ongoing efforts on synthesizing mononuclear single-ion magnets (SIMs) with promising applications in high-density data storage and spintronics devices, the linear or quasi-linear Fe(I) complexes emerge as the enticing candidates possessing large unquenched angular momentum. Herein, we have studied five experimentally synthesized linear Fe(I) complexes to uncover the origin of single-molecule magnetic behavior of these complexes. To begin with, we benchmarked the methodology on the experimentally and theoretically well-studied complex [Fe(C(SiMe3)3)2]-1 (1) (SiMe3 = trimethylsilyl), which is characterized with a large spin-reversal barrier of 226 cm-1. Subsequently, the spin-phonon coupling coefficients are calculated for the low-frequency vibrational modes to understand the relaxation mechanism of the complex. Furthermore, the two Fe(I) complexes, that is, [Fe(cyIDep)2]+1 (2) (cyIDep = 1,3-bis(2',6'-diethylphenyl)-4,5-(CH2)4-imidazole-2-ylidene) and [Fe(sIDep)2]+1 (3) (sIDep = 1,3-bis(2',6'-diethylphenyl)-imidazolin-2-ylidene), are studied that are experimentally reported with no SIM behavior under ac or dc magnetic fields; however, they exhibit large opposite axial zero field splitting (-62.4 and +34.0 cm-1, respectively) from ab initio calculations. We have unwrapped the origin of this contrasting observation between experiment and theory by probing their magnetic relaxation pathways and the pattern of d orbital splitting. Additionally, the two experimentally synthesized Fe(I) complexes, that is, [(η6-C6H6)FeAr*-3,5-Pr2i] (4) (Ar*-3,5-Pr2i = C6H-2,6-(C6H2-2,4,6-Pr3i)2-3,5-Pr2i) and [(CAAC)2Fe]+1 (5) (CAAC = cyclic (alkyl) (amino)carbene), are investigated for SIM behavior, since there is no report on their magnetic anisotropy. To this end, complex 4 presents itself as the possible candidate for SIM.
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Affiliation(s)
- Rishu Khurana
- Institute of Nano Science and Technology, Sector-81, Mohali, Punjab 140306, India
| | - Md Ehesan Ali
- Institute of Nano Science and Technology, Sector-81, Mohali, Punjab 140306, India
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36
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Storm Thomsen M, Andersen HOB, Sørensen TJ. Long story short: donor set symmetry in [Eu(DOTA)(H 2O)] - crystals determines the electronic structure. Dalton Trans 2022; 51:14118-14124. [PMID: 36043508 DOI: 10.1039/d2dt02172b] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Lanthanide complexes of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid DOTA have been studied in great detail due to their use as MRI contrast agents. Since the first report from Desreux in 1980, the Ln[DOTA]- complexes of gadolinium(III) in particular have been thoroughly investigated. The forms of the nine-coordinated [Ln(DOTA)(H2O)]- complexes are well known, and the ligand backbone has been used extensively to create functional MRI contrast agents, luminescent probes, and as a model system for studying the properties of lanthanide(III) ions. In solution, the photophysical properties have been mapped, but as the structures are not known, direct structure-property relationships have not been created. Here, the electronic properties of two Eu[DOTA] compounds (1 and 2) and a Eu[DOTA]-like compound (3) were studied using single-crystal luminescence spectroscopy. The donor set in the three compounds is identical (4N 4O 1O), and using the symmetry deviation value σideal it was shown that the coordination geometry is close to identical. Nevertheless, the electronic properties evaluated using the luminescence spectrum were found to differ significantly between the three compounds. The magnitude of the crystal field splitting was found not to scale with the symmetry of the coordination geometry. It was concluded that the donor set dictates the splitting, yet the structure-property relationships governing the electronic properties of europium(III) ions still elude us.
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Affiliation(s)
- Maria Storm Thomsen
- Nano-Science Center & Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark.
| | - Helene Obel Bøch Andersen
- Nano-Science Center & Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark.
| | - Thomas Just Sørensen
- Nano-Science Center & Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark.
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37
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Rousset E, Piccardo M, Gable RW, Massi M, Sorace L, Soncini A, Boskovic C. Elucidation of LMCT Excited States for Lanthanoid Complexes: A Theoretical and Solid-State Experimental Framework. Inorg Chem 2022; 61:14004-14018. [PMID: 35998349 DOI: 10.1021/acs.inorgchem.2c01985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Photophysical and magnetic properties arising from both ground and excited states of lanthanoid ions are relevant for numerous applications. These properties can be substantially affected, both adversely and beneficially, by ligand-to-metal charge-transfer (LMCT) states. However, probing LMCT states remains a significant challenge in f-block chemistry, particularly in the solid state. Intriguingly, the europium compounds [EuIII(18-c-6)(X4Cat)(NO3)]·MeCN (18-c-6 = 18-crown-6; X = Cl (tetrachlorocatecholate, 1-Eu) or Br (tetrabromocatecholate, 2-Eu) are distinctly darkly-colored, in marked contrast to the analogues with other lanthanoid ions in the 1-Ln and 2-Ln series (Ln = La, Ce, Nd, Gd, Tb, and Dy). Herein, we report a multi-technique investigation of these compounds that has allowed elucidation of the LMCT character of the relevant absorption bands using magnetometry, absorption and emission spectroscopies, and solid-state electrochemistry. To support experimental observations, we present a semi-quantitative multireference ab initio model that (i) captures the anomalously low-lying LMCT excited state observed in the visible spectrum of 1-Eu (and its absence in the other 1-Ln analogues); (ii) elucidates the contribution of the LMCT excitation to the crystal field split 7FJ ground-state wave functions; and (iii) identifies the crucial role played by radial dynamical correlation of the EuIII 4f electrons in the description of the LMCT excited state, modeled by the inclusion of 4f → 5f excitations in the optimized wave function. By providing a set of experimental and theoretical tools, this work establishes a framework for the elucidation of LMCT excited states in lanthanoid compounds in the solid state.
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Affiliation(s)
- Elodie Rousset
- School of Chemistry, University of Melbourne, Parkville, VIC 3010, Australia
| | - Matteo Piccardo
- School of Chemistry, University of Melbourne, Parkville, VIC 3010, Australia
| | - Robert W Gable
- School of Chemistry, University of Melbourne, Parkville, VIC 3010, Australia
| | - Massimiliano Massi
- School of Molecular and Life Sciences─Curtin Institute for Functional Materials and Interfaces, Curtin University, Kent Street, Bentley, WA 6102, Australia
| | - Lorenzo Sorace
- UdR INSTM and Department of Chemistry "U. Schiff", University of Florence, Sesto Fiorentino, FI 50019, Italy
| | - Alessandro Soncini
- School of Chemistry, University of Melbourne, Parkville, VIC 3010, Australia
| | - Colette Boskovic
- School of Chemistry, University of Melbourne, Parkville, VIC 3010, Australia
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38
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Lunghi A. Toward exact predictions of spin-phonon relaxation times: An ab initio implementation of open quantum systems theory. SCIENCE ADVANCES 2022; 8:eabn7880. [PMID: 35930642 PMCID: PMC9355363 DOI: 10.1126/sciadv.abn7880] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 06/23/2022] [Indexed: 05/28/2023]
Abstract
Spin-phonon coupling is the main driver of spin relaxation and decoherence in solid-state semiconductors at finite temperature. Controlling this interaction is a central problem for many disciplines, ranging from magnetic resonance to quantum technologies. Spin relaxation theories have been developed for almost a century but often use a phenomenological description of phonons and their coupling to spin, resulting in a nonpredictive tool and hindering our detailed understanding of spin dynamics. Here, we combine time-local master equations up to the fourth order with advanced electronic structure methods and perform predictions of spin-phonon relaxation time for a series of solid-state coordination compounds based on both transition metals and lanthanide Kramers ions. The agreement between experiments and simulations demonstrates that an accurate, universal, and fully ab initio implementation of spin relaxation theory is possible, thus paving the way to a systematic study of spin-phonon relaxation in solid-state materials.
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Affiliation(s)
- Alessandro Lunghi
- School of Physics, AMBER and CRANN Institute, Trinity College, Dublin 2, Ireland
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39
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Soncini A, Piccardo M. Ab initio non-covalent crystal field theory for lanthanide complexes: a multiconfigurational non-orthogonal group function approach. Phys Chem Chem Phys 2022; 24:18915-18930. [PMID: 35913488 DOI: 10.1039/d1cp05488k] [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
We present a multiconfigurational ab initio methodology based on non-orthogonal fragments for the calculation of crystal field energy levels and magnetic properties of lanthanide complexes, implementing a systematic description of non-covalent contributions to metal-ligand bonding. The approach consists of two steps. In the first step, appropriate ab initio wave functions for the various ionic fragments (lanthanide ions and coordinating ligands) are optimized separately, accounting for the influence of the surrounding environment within various approximations. In the second and final step, the scalar relativistic (DKH2) electrostatic Hamiltonian of the whole molecule is represented on the basis of the optimized metal-ligand multiconfigurational non-orthogonal group functions (MC-NOGFs), and reduced to an effective (2J + 1)-dimensional non-orthogonal configuration interaction (CI) problem via Löwdin-partitioning. Within the proposed formalism, the projected non-orthogonal CI Hamiltonian can be expanded to any desired order of perturbation theory in the fragment-localised excitations out of the degenerate space, and its eigenvalues and eigenfunctions provide systematic approximations to the crystal field energies and wave functions. We present here a preliminary implementation of the proposed MC-NOGF method developed for first-order degenerate perturbation theory within our own ab initio code CERES, and compare its performance both with the simpler non-covalent orthogonal ab initio approach, Fragment Ab Initio Model Potential (FAIMP) approximation, and the full CAHF/CASCI-SO method, accounting for metal-ligand covalency in a mean-field manner. We found that the energies and magnetic properties of 44 complexes obtained via an iteratively optimized version of our MC-NOGF first-order non-covalent method compare remarkably well with those obtained using the full CAHF/CASCI-SO method including metal-ligand covalency, thus exposing the predominantly electrostatic character of the metal-ligand interactions, and are superior to those obtained using the FAIMP approach, which in its iteratively optimised variant was believed to date to be the best ab initio description of non-covalent metal-ligand interactions.
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Affiliation(s)
- Alessandro Soncini
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova, Via Marzolo 1, 35131 Padova, Italy. .,School of Chemistry, The University of Melbourne, Australia
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40
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Dergachev VD, Nakritskaia DD, Varganov SA. Strong Relativistic Effects in Lanthanide-Based Single-Molecule Magnets. J Phys Chem Lett 2022; 13:6749-6754. [PMID: 35852301 DOI: 10.1021/acs.jpclett.2c01627] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Lanthanide-based single-molecule magnets (SMMs) are promising building blocks for quantum memory and spintronic devices. Designing lanthanide-based SMMs with long spin relaxation time requires a detailed understanding of their electronic structure, including the crucial role of the spin-orbit coupling (SOC). While traditional calculations of SOC using the perturbation theory applied to a solution of the nonrelativistic Schrödinger equation are valid for light atoms, this approach is questionable for systems containing heavy elements such as lanthanides. We investigate the accuracy of the perturbation estimates of SOC by variationally solving the Dirac equation for the [DyO]+ molecule, a prototype of a lanthanide-based SMM. We show that the energy splittings between the M J states involved in spin relaxation depend on the interplay between strong SOC and dynamic electron correlation. We demonstrate that this interplay affects the resonances between the spin and vibrational transitions and, therefore, the spin relaxation time.
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Affiliation(s)
- Vsevolod D Dergachev
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, Nevada 89557-0216, United States
| | - Daria D Nakritskaia
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, Nevada 89557-0216, United States
| | - Sergey A Varganov
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, Nevada 89557-0216, United States
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41
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Razquin-Bobillo L, Pajuelo-Corral O, Artetxe B, Zabala-Lekuona A, Choquesillo-Lazarte D, Rodríguez-Diéguez A, San Sebastian E, Cepeda J. Combined experimental and theoretical investigation on the magnetic properties derived from the coordination of 6-methyl-2-oxonicotinate to 3d-metal ions. Dalton Trans 2022; 51:9780-9792. [PMID: 35704920 DOI: 10.1039/d2dt00838f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Five new compounds are reported herein starting from 2-hydroxy-6-methylnicotinic acid (H2h6mnic) and first-row transition metal ions, although H2h6mnic shows a prototropy in solution to lead to the 6-methyl-2-oxonicotinate (6m2onic) ligand that is the molecule eventually present in the compounds. The structural and chemical characterization reveals the following chemical formulae: {[MnNa(μ3-6m2onic)2(μ-6m2onic)(MeOH)]·H2O·MeOH}n (1Mn), {[M2Na2(μ3-6m2onic)2(μ-6m2onic)2(μ-H2O)(H2O)6](NO3)2}n [MII = Co (2Co) and Ni (3Ni)], 2[Cu2(6m2onic)3(μ-6m2onic)(MeOH)]·[Cu2(6m2onic)2(μ-6m2onic)2]·2[Cu(6m2onic)2(MeOH)]·32H2O (4Cu) and {[Cu(μ-6m2onic)2]·6H2O}n (5Cu) (where 6m2onic = 6-methyl-2-oxonicotinate). An unusual structural diversity is observed for the compounds, ranging from isolated complexes (in 4Cu), 1D arrays (in 1Mn and 5Cu) and 3D frameworks (in 2Co and 3Ni). Magnetic properties have been studied for all compounds. Analysis of the magnetic dc susceptibility and magnetization data for 4Cu and 5Cu suggests the occurrence of ferromagnetic exchange, which is well explained by broken-symmetry and CASSCF calculations. The sizeable easy-plane magnetic anisotropy present in compound 2Co allows for a field-induced magnet behaviour with an experimental effective energy barrier of 16.2 cm-1, although the slow relaxation seems to be best described through Raman and direct processes in agreement with the results of ab initio calculations.
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Affiliation(s)
- Laura Razquin-Bobillo
- Departamento de Química Aplicada, Facultad de Química, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 20018 Donostia-San Sebastián, Spain.
| | - Oier Pajuelo-Corral
- Departamento de Química Aplicada, Facultad de Química, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 20018 Donostia-San Sebastián, Spain.
| | - Beñat Artetxe
- Departamento de Química Orgánica e Inorgánica, Facultad de Ciencia y Tecnología, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 48940, Leioa, Spain
| | - Andoni Zabala-Lekuona
- Departamento de Química Aplicada, Facultad de Química, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 20018 Donostia-San Sebastián, Spain.
| | - Duane Choquesillo-Lazarte
- Laboratorio de Estudios Cristalográficos, IACT, CSIC-Universidad de Granada, Avda. de las Palmeras 4, 18100 Armilla, Spain
| | - Antonio Rodríguez-Diéguez
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain
| | - Eider San Sebastian
- Departamento de Química Aplicada, Facultad de Química, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 20018 Donostia-San Sebastián, Spain.
| | - Javier Cepeda
- Departamento de Química Aplicada, Facultad de Química, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 20018 Donostia-San Sebastián, Spain.
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42
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Islam MA, Autillo M, Guérin L, Tamain C, Moisy P, Bolvin H, Berthon C. Dipolar and Contact Paramagnetic NMR Chemical Shifts in An IV Complexes with Dipicolinic Acid Derivatives. Inorg Chem 2022; 61:10329-10341. [PMID: 35749686 DOI: 10.1021/acs.inorgchem.2c00845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Actinide +IV complexes (AnIV = ThIV, UIV, NpIV, and PuIV) with two dipicolinic acid derivatives (DPA and Et-DPA) have been studied by 1H and 13C NMR spectroscopies and first-principles calculations. The Fermi contact and dipolar contributions to the actinide-induced shifts (AIS) are evaluated from a temperature dependence analysis, combined with ab initio results. It allows an experimental estimation of the axial anisotropy of the magnetic susceptibility Δχax and of the hyperfine coupling constants of the NMR-active nuclei. Due to the compactness of the coordination sphere, the magnetic anisotropy of the paramagnetic center is small, and this makes the contact contribution to be the dominant one, even on the remote atoms. The sign of the hyperfine coupling constants and related spin densities is alternating on the nuclei of the ligand cycle, denoting a preponderant spin polarization mechanism. This is well reproduced by unrestricted density functional theory (DFT) calculations. Those values are furthermore slightly decreasing in the actinide series, which indicates a small decrease of the covalency from UIV to PuIV.
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Affiliation(s)
- Md Ashraful Islam
- Laboratoire de Chimie et Physique Quantiques, CNRS, Université Toulouse III, 118 Route de Narbonne, 31062 Toulouse, France
| | | | - Laetitia Guérin
- CEA, DES, ISEC, DMRC, Univ. Montpellier, Marcoule 30207, France
| | | | - Philippe Moisy
- CEA, DES, ISEC, DMRC, Univ. Montpellier, Marcoule 30207, France
| | - Hélène Bolvin
- Laboratoire de Chimie et Physique Quantiques, CNRS, Université Toulouse III, 118 Route de Narbonne, 31062 Toulouse, France
| | - Claude Berthon
- CEA, DES, ISEC, DMRC, Univ. Montpellier, Marcoule 30207, France
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43
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Shao D, Xu F, Yin L, Li H, Sun Y, Ouyang Z, Wang Z, Zhang Y, Wang X. Fine‐Tuning
of Structural Distortion and Magnetic Anisotropy by Organosulfonates in Octahedral Cobalt(
II
) Complexes. CHINESE J CHEM 2022. [DOI: 10.1002/cjoc.202200284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Dong Shao
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering Nanjing University Nanjing 210023 P. R. China
- Hubei Key Laboratory of Processing and Application of Catalytic Materials, College of Chemistry and Chemical Engineering Huanggang Normal University Huanggang 438000 P. R. China
| | - Fang‐Xue Xu
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering Nanjing University Nanjing 210023 P. R. China
| | - Lei Yin
- Wuhan National High Magnetic Field Centre Huazhong University of Science and Technology Wuhan 430074 P. R. China
| | - Hong‐Qing Li
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering Nanjing University Nanjing 210023 P. R. China
| | - Yu‐Chen Sun
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering Nanjing University Nanjing 210023 P. R. China
| | - Zhong‐Wen Ouyang
- Wuhan National High Magnetic Field Centre Huazhong University of Science and Technology Wuhan 430074 P. R. China
| | - Zhen‐Xing Wang
- Wuhan National High Magnetic Field Centre Huazhong University of Science and Technology Wuhan 430074 P. R. China
| | - Yi‐Quan Zhang
- Jiangsu Key Laboratory for NSLSCS, School of Physical Science and Technology Nanjing Normal University Nanjing 210097 P. R. China
| | - Xin‐Yi Wang
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering Nanjing University Nanjing 210023 P. R. China
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44
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Storm Thomsen M, Anker AS, Kacenauskaite L, Sørensen TJ. We are never ever getting (back to) ideal symmetry: structure and luminescence in a ten-coordinated europium(III) sulfate crystal. Dalton Trans 2022; 51:8960-8963. [PMID: 35660819 DOI: 10.1039/d2dt01522f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Our theoretical treatment of electronic structures in coordination complexes often rests on assumptions of symmetry. Experiments rarely provide fully symmetric systems to study. In solutions, fluctuations in solvation, variations in conformations, and even changes in constitution occur and complicate the picture. In crystals, lattice distortion, energy transfer, and phonon quenching play a role, but we are able to identify distinct symmetries. Yet the question remains: How is the real symmetry in a crystal compared to ideal symmetries?
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Affiliation(s)
- Maria Storm Thomsen
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 København Ø, Denmark.
| | - Andy S Anker
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 København Ø, Denmark.
| | - Laura Kacenauskaite
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 København Ø, Denmark.
| | - Thomas Just Sørensen
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 København Ø, Denmark.
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45
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Kumar K, Stefanczyk O, Nakabayashi K, Mineo Y, Ohkoshi SI. Development of Nd (III)-Based Terahertz Absorbers Revealing Temperature Dependent Near-Infrared Luminescence. Int J Mol Sci 2022; 23:ijms23116051. [PMID: 35682730 PMCID: PMC9181137 DOI: 10.3390/ijms23116051] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 05/25/2022] [Accepted: 05/26/2022] [Indexed: 02/06/2023] Open
Abstract
Molecular vibrations in the solid-state, detectable in the terahertz (THz) region, are the subject of research to further develop THz technologies. To observe such vibrations in terahertz time-domain spectroscopy (THz-TDS) and low-frequency (LF) Raman spectroscopy, two supramolecular assemblies with the formula [NdIII (phen)3 (NCX)3] 0.3EtOH (X = S, 1-S; Se, 1-Se) were designed and prepared. Both compounds show several THz-TDS and LF-Raman peaks in the sub-THz range, with the lowest frequencies of 0.65 and 0.59 THz for 1-S and 1-Se, and 0.75 and 0.61 THz for 1-S and 1-Se, respectively. The peak redshift was observed due to the substitution of SCN− by SeCN−. Additionally, temperature-dependent TDS-THz studies showed a thermal blueshift phenomenon, as the peak position shifted to 0.68 THz for 1-S and 0.62 THz for 1-Se at 10 K. Based on ab initio calculations, sub-THz vibrations were ascribed to the swaying of the three thiocyanate/selenocyanate. Moreover, both samples exhibited near-infrared (NIR) emission from Nd (III), and very good thermometric properties in the 300–150 K range, comparable to neodymium (III) oxide-based thermometers and higher than previously reported complexes. Moreover, the temperature dependence of fluorescence and THz spectroscopy analysis showed that the reduction in anharmonic thermal vibrations leads to a significant increase in the intensity and a reduction in the width of the emission and LF absorption peaks. These studies provide the basis for developing new routes to adjust the LF vibrational absorption.
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46
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Nguyen GT, Ungur L. The Role of Radical Bridges in Polynuclear Single‐Molecule Magnets. Chemistry 2022; 28:e202200227. [DOI: 10.1002/chem.202200227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Indexed: 11/08/2022]
Affiliation(s)
- Giang Truong Nguyen
- Department of Chemistry Faculty of Science National University of Singapore Block S8 Level 3, 3 Science Drive 3 Singapore Singapore 117543
| | - Liviu Ungur
- Department of Chemistry Faculty of Science National University of Singapore Block S8 Level 3, 3 Science Drive 3 Singapore Singapore 117543
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47
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Liu H, Li JF, Yin B. The coexistence of long τQTM and high Ueff as a concise criterion for a good single-molecule magnet: a theoretical case study of square antiprism dysprosium single-ion magnets. Phys Chem Chem Phys 2022; 24:11729-11742. [PMID: 35506508 DOI: 10.1039/d2cp00776b] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A systematic theoretical study is performed on a group of 16 square antiprism dysprosium single-ion magnets. Based on ab initio calculations, the quantum tunneling of magnetization (QTM) time, i.e., τQTM, and effective barrier of magnetic reversal, Ueff, are theoretically predicted. The theoretical τQTM is able to identify the ones with the longest QTM time with small numerical deviations. Similar results occur with respect to Ueff too. The systems possessing the best single-molecule magnet (SMM) properties here are just the ones having both the longest τQTM and the highest Ueff, from either experiment or theory. Thus, our results suggest the coexistence of long τQTM and high Ueff to be a criterion for high-performance SMMs. Although having its own limits, this criterion is easy to be applied in a large number of systems since both τQTM and Ueff could be predicted by theory with satisfactory efficiency and reliability. Therefore, this concise criterion could provide screened candidates for high-performance SMMs quickly and, hence, ease the burden of further exploration aiming for a higher degree of precision. This screening is important since the further exploration could easily demand tens or even hundreds of ab initio calculations for a single SMM. A semi-quantitative crystal field (CF) analysis is performed and shown here to be capable of indicating the general trends in a more chemically intuitive way. This analysis could help to identify the most important coordinating atoms for both diagonal and non-diagonal CF components. Thus, it could give some direct clues for improving the SMM properties: reducing the distance of the axial atom to the central ion, rotating the axial atom closer to the easy axis or increasing the amount of its negative charge. Correspondingly, opposite operations on the equatorial atom could give the same result.
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Affiliation(s)
- Hong Liu
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, Lab of Theoretical Molecular Magnetism, College of Chemistry and Materials Science, Northwest University, Xi'an, 710127, P. R. China.
| | - Jin-Feng Li
- College of Chemistry and Chemical Engineering, Yan'an University, Yan'an, 716000, P. R. China
| | - Bing Yin
- Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, Lab of Theoretical Molecular Magnetism, College of Chemistry and Materials Science, Northwest University, Xi'an, 710127, P. R. China.
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48
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Durrant JP, Day BM, Tang J, Mansikkamäki A, Layfield RA. Dominance of Cyclobutadienyl Over Cyclopentadienyl in the Crystal Field Splitting in Dysprosium Single-Molecule Magnets. Angew Chem Int Ed Engl 2022; 61:e202200525. [PMID: 35108431 PMCID: PMC9302998 DOI: 10.1002/anie.202200525] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Indexed: 01/12/2023]
Abstract
Replacing a monoanionic cyclopentadienyl (Cp) ligand in dysprosium single‐molecule magnets (SMMs) with a dianionic cyclobutadienyl (Cb) ligand in the sandwich complexes [(η4‐Cb′′′′)Dy(η5‐C5Me4tBu)(BH4)]− (1), [(η4‐Cb′′′′)Dy(η8‐Pn†)K(THF)] (2) and [(η4‐Cb′′′′)Dy(η8‐Pn†)]− (3) leads to larger energy barriers to magnetization reversal (Cb′′′′=C4(SiMe3)4, Pn†=1,4‐di(tri‐isopropylsilyl)pentalenyl). Short distances to the Cb′′′′ ligands and longer distances to the Cp ligands in 1–3 are consistent with the crystal field splitting being dominated by the former. Theoretical analysis shows that the magnetic axes in the ground Kramers doublets of 1–3 are oriented towards the Cb′′′′ ligands. The theoretical axiality parameter and the relative axiality parameter Z and Zrel are introduced to facilitate comparisons of the SMM performance of 1–3 with a benchmark SMM. Increases in Z and Zrel when Cb′′′ replaces Cp signposts a route to SMMs with properties that could surpass leading systems.
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Affiliation(s)
- James P Durrant
- Department of Chemistry, University of Sussex Falmer, Brighton, BN1 9QR, UK
| | - Benjamin M Day
- Department of Chemistry, University of Sussex Falmer, Brighton, BN1 9QR, UK
| | - Jinkui Tang
- State Key Laboratory of Rare Earth Resource Utilization, Changchun, Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, P.R. China
| | | | - Richard A Layfield
- Department of Chemistry, University of Sussex Falmer, Brighton, BN1 9QR, UK
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49
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Ungur L, Szabo B, ALOthman ZA, Al-Kahtani AAS, Chibotaru LF. Mechanisms of Luminescence in Lanthanide Complexes: A Crucial Role of Metal-Ligand Covalency. Inorg Chem 2022; 61:5972-5976. [PMID: 35420038 DOI: 10.1021/acs.inorgchem.2c00071] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A current understanding of the luminescence of lanthanide complexes is based on the phenomenological Judd-Ofelt (JO) theory. However, the mechanisms of electric-dipole transitions lying at its basis were never subjected to a rigorous analysis. Here, we investigate the contributions to the electric-dipole transitions in the Er3+ 4S3/2 → 4I15/2 band of an erbium trensal complex using state-of-the-art ab initio calculations. We find that the conventional JO mechanism based on the electrostatic crystal field yields only a quarter of the integral intensity of this band. Accordingly, three quarters of it is contributed by covalent binding of erbium and ligand orbitals via three major mechanisms, the 4f ligand and ligand-ligand electric-dipole transitions and covalent enhancement of the hybridization of 4f and even empty orbitals of erbium. We expect that these findings will inspire the design of efficient rare-earth luminescent materials.
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Affiliation(s)
- Liviu Ungur
- Department of Chemistry, National University of Singapore, Block S8, Level 3, 3 Science Drive 3, Singapore 117543, Singapore
| | - Bernat Szabo
- Theory of Nanomaterials Group, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Leuven B-3001, Belgium
| | - Zeid A ALOthman
- Chemistry Department, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Abdullah A S Al-Kahtani
- Chemistry Department, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Liviu F Chibotaru
- Theory of Nanomaterials Group, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Leuven B-3001, Belgium.,Chemistry Department, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
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50
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Guo FS, He M, Huang GZ, Giblin SR, Billington D, Heinemann FW, Tong ML, Mansikkamäki A, Layfield RA. Discovery of a Dysprosium Metallocene Single-Molecule Magnet with Two High-Temperature Orbach Processes. Inorg Chem 2022; 61:6017-6025. [PMID: 35420419 PMCID: PMC9044448 DOI: 10.1021/acs.inorgchem.1c03980] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Magnetic bistability
in single-molecule magnets (SMMs) is a potential
basis for new types of nanoscale information storage material. The
standard model for thermally activated relaxation of the magnetization
in SMMs is based on the occurrence of a single Orbach process. Here,
we show that incorporating a phosphorus atom into the framework of
the dysprosium metallocene [(CpiPr5)Dy(CpPEt4)]+[B(C6F5)4]− (CpiPr5 is penta-isopropylcyclopentadienyl,
CpPEt4 is tetraethylphospholyl) leads to the occurrence
of two distinct high-temperature Orbach processes, with energy barriers
of 1410(10) and 747(7) cm–1, respectively. These
barriers provide experimental evidence for two different spin–phonon
coupling regimes, which we explain with the aid of ab initio calculations.
The strong and highly axial crystal field in this SMM also allows
magnetic hysteresis to be observed up to 70 K, using a scan rate of
25 Oe s–1. In characterizing this SMM, we show that
a conventional Debye model and consideration of rotational contributions
to the spin–phonon interaction are insufficient to explain
the observed phenomena. A
phospholyl-ligated dysprosium metallocene single-molecule
magnet shows two high-temperature Orbach relaxation processes with
effective energy barriers of 1410(10) and 747(7) cm−1, and magnetic hysteresis up to 70 K when using a scan rate of 25
Oe s−1.
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Affiliation(s)
- Fu-Sheng Guo
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QR, U.K
| | - Mian He
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QR, U.K
| | - Guo-Zhang Huang
- Key Laboratory of Bioinorganic and Synthetic Chemistry of the Ministry of Education, School of Chemistry, Sun-Yat Sen University, Guangzhou 510006, P. R. China
| | - Sean R Giblin
- School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA, U.K
| | - David Billington
- School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA, U.K
| | - Frank W Heinemann
- Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich-Alexander-University Erlangen-Nürnberg, Egerlandstrabe 1, 91058 Erlangen, Germany
| | - Ming-Liang Tong
- Key Laboratory of Bioinorganic and Synthetic Chemistry of the Ministry of Education, School of Chemistry, Sun-Yat Sen University, Guangzhou 510006, P. R. China
| | - Akseli Mansikkamäki
- NMR Research Group, University of Oulu, P.O. Box 8000, Oulu FI-90014, Finland
| | - Richard A Layfield
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QR, U.K
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