1
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Heim P, Biswas S, Lopez H, Gericke R, Twamley B, McDonald AR. A Co II-Hydroxide Complex That Converts Directly to a Co II-Acetamide during Catalytic Nitrile Hydration. Inorg Chem 2024; 63:7896-7902. [PMID: 38607349 PMCID: PMC11061833 DOI: 10.1021/acs.inorgchem.4c00754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 03/25/2024] [Accepted: 04/01/2024] [Indexed: 04/13/2024]
Abstract
In exploring structural and functional mimics of nitrile hydratases, we report the synthesis of the pseudo-trigonal bipyramidal CoII complexes (K)[CoII(DMF)(LPh)] (1(DMF)), (NMe4)2[CoII(OAc)(LPh)] (1(OAc)), and (NMe4)2[CoII(OH)(LPh)] (1(OH)) (LPh = 2,2',2''-nitrilo-tris-(N-phenylacetamide; DMF = N,N-dimethylformamide; -OAc = acetate)). The complexes were characterized using NMR, FT-IR, ESI-MS, electronic absorption spectroscopy, and X-ray crystallography, showing the LPh ligand to bind in a tetradentate tripodal fashion alongside the respective ancillary donor. One of the complexes, 1(OH), is an unusual structural and functional mimic of the Co active site in Co nitrile hydratases. 1(OH) reacted with acetonitrile to yield the CoII-acetamide complex (NMe4)2[CoII(NHC(O)CH3)(LPh)], 2, which was also thoroughly characterized. In the presence of excess hydroxide, 1(OH) was found to catalyze quantitative conversion of the added hydroxide into acetamide. Despite the differences in Co oxidation state in nitrile hydratases and 1(OH) (CoIII versus CoII, respectively), 1(OH) was nonetheless an effective nitrile hydration catalyst, selectively producing acetamide over multiple turnovers.
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Affiliation(s)
- Philipp Heim
- School
of Chemistry, Trinity College Dublin, The
University of Dublin, College Green, Dublin 2, Ireland
| | - Sachidulal Biswas
- School
of Chemistry, Trinity College Dublin, The
University of Dublin, College Green, Dublin 2, Ireland
| | - Hugo Lopez
- School
of Chemistry, Trinity College Dublin, The
University of Dublin, College Green, Dublin 2, Ireland
| | - Robert Gericke
- School
of Chemistry, Trinity College Dublin, The
University of Dublin, College Green, Dublin 2, Ireland
- Helmholtz-Zentrum
Dresden-Rossendorf e.V., Institute of Resource
Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Brendan Twamley
- School
of Chemistry, Trinity College Dublin, The
University of Dublin, College Green, Dublin 2, Ireland
| | - Aidan R. McDonald
- School
of Chemistry, Trinity College Dublin, The
University of Dublin, College Green, Dublin 2, Ireland
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2
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Nagelski AL, Ozerov M, Fataftah MS, Krzystek J, Greer SM, Holland PL, Telser J. Electronic Structure of Three-Coordinate Fe II and Co II β-Diketiminate Complexes. Inorg Chem 2024; 63:4511-4526. [PMID: 38408452 DOI: 10.1021/acs.inorgchem.3c03388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
The β-diketiminate supporting group, [ArNCRCHCRNAr]-, stabilizes low coordination number complexes. Four such complexes, where R = tert-butyl, Ar = 2,6-diisopropylphenyl, are studied: (nacnactBu)ML, where M = FeII, CoII and L = Cl, CH3. These are denoted FeCl, FeCH3, CoCl, and CoCH3 and have been previously reported and structurally characterized. The two FeII complexes (S = 2) have also been previously characterized by Mössbauer spectroscopy, but only indirect assessment of the ligand-field splitting and zero-field splitting (zfs) parameters was available. Here, EPR spectroscopy is used, both conventional field-domain for the CoII complexes (with S = 3/2) and frequency-domain, far-infrared magnetic resonance spectroscopy (FIRMS) for all four complexes. The CoII complexes were also studied by magnetometry. These studies allow accurate determination of the zfs parameters. The two FeII complexes are similar with nearly axial zfs and large magnitude zfs given by D = -37 ± 1 cm-1 for both. The two CoII complexes likewise exhibit large and nearly axial zfs, but surprisingly, CoCl has positive D = +55 cm-1 while CoCH3 has negative D = -49 cm-1. Theoretical methods were used to probe the electronic structures of the four complexes, which explain the experimental spectra and the zfs parameters.
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Affiliation(s)
- Alexandra L Nagelski
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
| | - Mykhaylo Ozerov
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Majed S Fataftah
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
| | - J Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Samuel M Greer
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Patrick L Holland
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, United States
| | - Joshua Telser
- Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605, United States
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3
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Titiš J, Rajnák C, Boča R. Limitations on the D-Parameter in Ni(II) Complexes. J Phys Chem A 2023; 127:6412-6424. [PMID: 37494700 DOI: 10.1021/acs.jpca.3c02543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/28/2023]
Abstract
A number of hexacoordinate, pentacoordinate, and tetracoordinate Ni(II) complexes have been investigated by applying ab initio CASSCF + NEVPT2 + SOC calculations and Generalized Crystal Field Theory. The geometry of the coordination polyhedron covers D4h, D3h, D2h, D2d, C4v, C3v, and C2v symmetry. The calculated spin-Hamiltonian parameters D and E were compared to the available experimental data. The limiting values of the D-parameter in the class of Ni(II) complexes are identified. Magnetic anisotropy in Ni(II) complexes, expressed by the axial zero-field splitting parameter D, seriously depends upon the ground and first excited electronic states. In hexacoordinate complexes, the ground electronic term is nondegenerate 3B1g for the D4h symmetry; D is slightly positive or negative. In tetracoordinate systems, D is only positive when the electronic ground state is nondegenerate 3A or 3B; this diverges on the τ4 path when oblate bisphenoid approaches the prolate geometry and a level crossing with 3E occurs. In pentacoordinate systems, D could be extremely negative when approaching a trigonal bipyramid (Addison index τ5 ∼ 1, ground state 3E″). In pentacoordinate Ni(II) complexes with the D3h and C3v symmetry of the coordination polyhedron, the ground electronic term is orbitally doubly degenerate which causes the D-parameter stays undefined. It is emphasized that one has to inspect compositions of the spin-orbit multiplets from the spin states |MS⟩ and check whether the weights confirm the expected spin-Hamiltonian picture: with D > 0, the ground state contains a dominant part of |0⟩ (close to 100%) whereas with D < 0 the spin-orbit doublet is formed of |±1⟩ with high weights (approaching 50 + 50%). The calculations show that the situations are not black and white, and the mixing of the states might be more complex especially when the rhombic zero-field splitting parameter E is in the play. In the case of the 3E ground term, six spin-orbit multiplets are formed by mixing six |MS⟩ states from the ground and quasi-degenerate excited states.
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Affiliation(s)
- Ján Titiš
- Department of Chemistry, Faculty of Natural Sciences, University of SS Cyril and Methodius, 91701 Trnava, Slovakia
| | - Cyril Rajnák
- Department of Chemistry, Faculty of Natural Sciences, University of SS Cyril and Methodius, 91701 Trnava, Slovakia
| | - Roman Boča
- Department of Chemistry, Faculty of Natural Sciences, University of SS Cyril and Methodius, 91701 Trnava, Slovakia
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4
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Georgiev M, Chamati H. Magnetic Behavior of Trigonal (Bi-)pyramidal 3d 8 Mononuclear Nanomagnets: The Case of [Ni(MDABCO) 2Cl 3]ClO 4. ACS OMEGA 2023; 8:28640-28650. [PMID: 37576657 PMCID: PMC10413474 DOI: 10.1021/acsomega.3c03208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 06/30/2023] [Indexed: 08/15/2023]
Abstract
This paper attempts to shed light on the origin of the magnetic behavior specific to trigonal bi- and pyramidal 3d8 mono- and polynuclear nanomagnets. The focus lies on entirely unraveling the system's intrinsic microscopic mechanisms and fundamental quantum mechanical relations governing the underlying electron dynamics. To this end, we develop a self-consistent approach to characterize, in great detail, all electron correlations and the ensuing fine structure of the energy spectra of a broad class of 3d8 systems. The mathematical framework is based on the multiconfigurational self-consistent field method and is devised to account for prospective quantum mechanical constraints that may confine the electron orbital dynamics while preserving the properties of all measurable quantities. We successfully characterize the experimentally observed magnetic anisotropy properties of a slightly distorted trigonal bipyramidal Ni2+ coordination complex, demonstrating that such compounds do not exhibit intrinsic huge zero-field splitting and inherent giant magnetic anisotropy. We reproduce qualitatively and quantitatively the behavior of the low-field magnetic susceptibility, magnetization, low-, and high-field electron paramagnetic resonance spectroscopy measurements and provide an in-depth analysis of the obtained results.
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Affiliation(s)
- Miroslav Georgiev
- Bulgarian Academy of Sciences, G Nadjakov Institute of Solid State Physics, Tsarigradsko Chaussée 72, 1784 Sofia, Bulgaria
| | - Hassan Chamati
- Bulgarian Academy of Sciences, G Nadjakov Institute of Solid State Physics, Tsarigradsko Chaussée 72, 1784 Sofia, Bulgaria
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5
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Hastings CD, Huffman LSX, Tiwari CK, Betancourth JG, Brennessel WW, Barnett BR. Coordinatively Unsaturated Metallates of Cobalt(II), Nickel(II), and Zinc(II) Guarded by a Rigid and Narrow Void. Inorg Chem 2023; 62:11920-11931. [PMID: 37462947 PMCID: PMC10394664 DOI: 10.1021/acs.inorgchem.3c01335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/01/2023]
Abstract
Both natural enzymatic systems and synthetic porous material catalysts utilize well-defined and uniform channels to dictate reaction selectivities on the basis of size or shape. Mimicry of this design element in homogeneous systems is generally difficult owing to the flexibility inherent in most small molecular species. Herein, we report the synthesis of a tripodal ligand scaffold that orients a narrow and rigid cavity atop accessible metal coordination space. The permanent void is formed through a macrocyclization reaction whereby the 3,5-dihydroxyphenyl arms are covalently linked through methylene bridges. Deprotonative metallation leads to anionic and coordinatively unsaturated complexes of divalent cobalt, nickel, and zinc. An analogous series of trigonal monopyramidal complexes bearing a nonmacrocyclized variant of the tripodal ligand are also reported. Physical characterization of the coordination complexes has been carried out using multiple spectroscopic techniques (NMR, EPR, and UV-vis), cyclic voltammetry, and X-ray diffraction. Complexes of the macrocyclized [LOCH2O]3- ligand retain a rigid cavity upon metallation, with this cavity guarding the entrance to the open axial coordination site. Through a combination of spectroscopic and computational studies, it is shown that acetonitrile entry into the void is sterically precluded, disrupting anticipated coordination at the intracavity site.
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Affiliation(s)
- Christopher D Hastings
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Lucy S X Huffman
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Chandan Kumar Tiwari
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | | | - William W Brennessel
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Brandon R Barnett
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
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6
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Fine Structure and the Huge Zero-Field Splitting in Ni 2+ Complexes. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27248887. [PMID: 36558020 PMCID: PMC9784865 DOI: 10.3390/molecules27248887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 12/11/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022]
Abstract
We perform a thorough study of the ground state magnetic properties of nickel-based 3d8 complexes. This includes an in-depth analysis of the contribution of the crystal field, spin exchange and spin-orbit interactions to the ground state magnetic properties. Of particular interest to the current investigation are the presence and occurrence of non-trivial zero-field splitting. The study focuses on the cases of Ni2+ ideal octahedral, trigonal bipyramidal, square planar and tetrahedral geometries. We provide results for the complete energy spectrum, the fine structure related to the ground state and the second set of excited states, low-field magnetic susceptibility and magnetization. In addition, we examine the zero-field fine structure in square pyramidal, trigonal pyramidal and trigonal planar complexes. The obtained results unequivocally show that a moderate or highly coordinated 3d8 complex can neither exhibit spin-orbit-driven large and giant magnetic anisotropy nor a huge zero-field splitting. Moreover, in the trigonal bipyramidal coordination, a fine structure associated to the ground state cannot result from the spin-orbit coupling alone.
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7
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Zhou Y, Zhang YL, Zhang Q, Yang SY, Wei XQ, Tian Z, Shao D. Supramolecular porous frameworks of two Ni(II) coordination polymers with varying structures, porosities, and magnetic properties. Polyhedron 2022. [DOI: 10.1016/j.poly.2022.116078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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8
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Liu M, Yang Y, Jing R, Zheng S, Yuan A, Wang Z, Luo SC, Liu X, Cui HH, Ouyang ZW, Chen L. Slow magnetic relaxation in dinuclear Co(III)-Co(II) complexes containing a five-coordinated Co(II) centre with easy-axis anisotropy. Dalton Trans 2022; 51:8382-8389. [PMID: 35587605 DOI: 10.1039/d2dt00857b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Two air-stable Co(III)-Co(II) mixed-valence complexes of molecular formulas [CoIICoIII(L)(DMAP)3(CH3COO)]·H2O·CH3OH (1) and [CoIICoIII(L)(4-Pyrrol)3 (CH3COO)]·0.5CH2Cl2 (2) (H4L = 1,3-bis-(5-methyl pyrazole-3-carboxamide) propane; DMAP = 4-dimethylaminopyridine; and 4-Pyrrol = 4-pyrrolidinopyridine) were synthesized and characterized by single-crystal X-ray crystallography, high-field electron paramagnetic resonance (HFEPR) spectroscopy, and magnetic measurements. Both complexes possess one five-coordinated paramagnetic Co(II) ion and one six-coordinated Co(III) ion with octahedral geometry. Direct-current magnetic susceptibility and magnetization measurements show the easy-axis magnetic anisotropy that is also confirmed by low-temperature HFEPR measurements and theoretical calculations. Frequency- and temperature-dependent alternating-current magnetic susceptibility measurements reveal their field-assisted slow magnetic relaxation, which is a characteristic behavior of single-molecule magnets (SMMs), caused by the individual Co(II) ion. The effective energy barrier of complex 1 (49.2 cm-1) is significantly higher than those of the other dinuclear Co(III)-Co(II) SMMs. This work hence presents the first instance of the dinuclear Co(III)-Co(II) single-molecule magnets with a five-coordinated environment around the Co(II) ion.
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Affiliation(s)
- Mengyao Liu
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, P. R. China.
| | - Yimou Yang
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, P. R. China.
| | - Rong Jing
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, P. R. China.
| | - Shaojun Zheng
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, P. R. China.
| | - Aihua Yuan
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, P. R. China.
| | - Zhenxing Wang
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology, Wuhan 430074, P. R. China.
| | - Shu-Chang Luo
- School of Chemical Engineering, Guizhou University of Engineering Science, Bijie 551700, P. R. China.
| | - Xiangyu Liu
- State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering, National Demonstration Center for Experimental Chemistry Education, College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, P. R. China.
| | - Hui-Hui Cui
- School of Chemistry and Chemical Engineering, Nantong University, Nantong 226019, P. R. China
| | - Zhong-Wen Ouyang
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology, Wuhan 430074, P. R. China.
| | - Lei Chen
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, P. R. China.
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9
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Lv W, Cui HH, Chen L, Zhang YQ, Chen XT, Wang Z, Ouyang ZW, Xue ZL. Magnetic anisotropy of two tetrahedral Co(II)-halide complexes with triphenylphosphine ligands. Dalton Trans 2022; 51:7530-7538. [PMID: 35506535 DOI: 10.1039/d2dt00121g] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recently, the choice of ligand and geometric control of mononuclear complexes, which can affect the relaxation pathways and blocking temperature, have received wide attention in the field of single-ion magnets (SIMs). To find out the influence of the coordination environment on SIMs, two four-coordinate mononuclear Co(II) complexes [NEt4][Co(PPh3)X3] (X = Cl-, 1; Br-, 2) have been synthesized and studied by X-ray single crystallography, magnetic measurements, high-frequency and -field EPR (HF-EPR) spectroscopy and theoretical calculations. Both complexes are in a cubic space group Pa3̄ (No. 205), containing a slightly distorted tetrahedral moiety with crystallographically imposed C3v symmetry through the [Co(PPh3)X3]- anion. The direct-current (dc) magnetic data and HF-EPR spectroscopy indicated the anisotropic S = 3/2 spin ground states of the Co(II) ions with the easy-plane anisotropy for 1 and 2. Ab initio calculations were performed to confirm the positive magnetic anisotropies of 1 and 2. Frequency- and temperature-dependent alternating-current (ac) magnetic susceptibility measurements revealed slow magnetic relaxation for 1 and 2 at an applied dc field. Finally, the magnetic properties of 1 and 2 were compared to those of other Co(II) complexes with a [CoAB3] moiety.
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Affiliation(s)
- Wei Lv
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
| | - Hui-Hui Cui
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
| | - Lei Chen
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, China
| | - Yi-Quan Zhang
- Jiangsu Key Laboratory for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing 210023, China
| | - Xue-Tai Chen
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
| | - Zhenxing Wang
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zhong-Wen Ouyang
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zi-Ling Xue
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA
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10
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Kornowicz A, Terlecki M, Justyniak I, Prochowicz D, van Leusen J, Kögerler P, Lewiński J. Cyclodextrin-Templated Co(II) Grids: Symmetry Control over Supramolecular Topology and Magnetic Properties. Inorg Chem 2022; 61:2499-2508. [PMID: 35072458 PMCID: PMC8826275 DOI: 10.1021/acs.inorgchem.1c03344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
While inherent complexation
properties and propensity for self-organization
of cyclodextrins (CDs) render them potentially promising scaffolds
of magnetic materials, this research area is still at an embryonic
stage. We report on the synthesis and structure characterization of
a new sandwich-type complex, [(α-CD)2Co3Li6(H2O)9] (α-1), which represents a smaller analogue of the previously characterized
[(γ-CD)2Co4Li8(H2O)12] (γ-1) cluster. A comprehensive
structural analysis of α-1 and a careful reinvestigation
of γ-1 reveal how the symmetry of CD ligands determines
the molecular composition and supramolecular arrangements of Co/Li
sandwich-type complexes. Furthermore, the first comparative studies
of the magnetic properties in this type of system point to subtle
differences in the magnetic behavior of both compounds. The sandwich-type
complexes α-1 and γ-1 exhibit
field-induced slow magnetic relaxation, defining a new family of magnetic
materials with a pillared grid-like supramolecular structure composed
of weakly interacting CoII centers forming an SMM. Cyclodextrin-based coordination systems
are potentially
promising scaffolds of supramolecular materials, including functional
magnetic systems. A comprehensive structural analysis of α-
and γ-cyclodextrin-based Co(II) coordination complexes reveals
how the symmetry of macrocyclic ligands determines the molecular composition
and supramolecular arrangements of Co/Li sandwich-type structures.
Furthermore, the first comparative studies of the magnetic properties
in this type of system point to subtle differences in the magnetic
behavior of both compounds.
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Affiliation(s)
- Arkadiusz Kornowicz
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Michał Terlecki
- Faculty of Chemistry,Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Iwona Justyniak
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Daniel Prochowicz
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Jan van Leusen
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, D-52074 Aachen, Germany
| | - Paul Kögerler
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, D-52074 Aachen, Germany
| | - Janusz Lewiński
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
- Faculty of Chemistry,Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
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11
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Luo R, Xu C, Tong JP, Shi H, Kong XJ, Fan Y, Shao F. Synthesis, structure and magnetism of a novel series of trinuclear nickel(II) clusters. CrystEngComm 2022. [DOI: 10.1039/d2ce00846g] [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
Five novel trinuclear nickel(II) clusters have been successfully synthesized, namely Ni3(fshz)2(L)4·n(sol) (H3fshz = N-formylsalicylhydrazide; L = pyridine, n = 0, 1; L = 4-methylpyridine, n = 1, sol = CH3CN,...
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12
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MacInnes MM, Jones ZR, Li B, Anderson NH, Batista ER, DiMucci IM, Eiroa-Lledo C, Knope KE, Livshits MY, Kozimor SA, Mocko V, Pace KA, Rocha FR, Stein BW, Wacker JN, Yang P. Using molten salts to probe outer-coordination sphere effects on lanthanide(III)/(II) electron-transfer reactions. Dalton Trans 2021; 50:15696-15710. [PMID: 34693951 DOI: 10.1039/d1dt02708e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Controlling structure and reactivity by manipulating the outer-coordination sphere around a given reagent represents a longstanding challenge in chemistry. Despite advances toward solving this problem, it remains difficult to experimentally interrogate and characterize outer-coordination sphere impact. This work describes an alternative approach that quantifies outer-coordination sphere effects. It shows how molten salt metal chlorides (MCln; M = K, Na, n = 1; M = Ca, n = 2) provided excellent platforms for experimentally characterizing the influence of the outer-coordination sphere cations (Mn+) on redox reactions accessible to lanthanide ions; Ln3+ + e1- → Ln2+ (Ln = Eu, Yb, Sm; e1- = electron). As a representative example, X-ray absorption spectroscopy and cyclic voltammetry results showed that Eu2+ instantaneously formed when Eu3+ dissolved in molten chloride salts that had strongly polarizing cations (like Ca2+ from CaCl2) via the Eu3+ + Cl1- → Eu2+ + ½Cl2 reaction. Conversely, molten salts with less polarizing outer-sphere M1+ cations (e.g., K1+ in KCl) stabilized Ln3+. For instance, the Eu3+/Eu2+ reduction potential was >0.5 V more positive in CaCl2 than in KCl. In accordance with first-principle molecular dynamics (FPMD) simulations, we postulated that hard Mn+ cations (high polarization power) inductively removed electron density from Lnn+ across Ln-Cl⋯Mn+ networks and stabilized electron-rich and low oxidation state Ln2+ ions. Conversely, less polarizing Mn+ cations (like K1+) left electron density on Lnn+ and stabilized electron-deficient and high-oxidation state Ln3+ ions.
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Affiliation(s)
- Molly M MacInnes
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Zachary R Jones
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Bo Li
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Nickolas H Anderson
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Enrique R Batista
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Ida M DiMucci
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Cecilia Eiroa-Lledo
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Karah E Knope
- Department of Chemistry, Georgetown University, 37th and O Streets NW, Washington, D.C. 20057, USA
| | - Maksim Y Livshits
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Stosh A Kozimor
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Veronika Mocko
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Kristen A Pace
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Francisca R Rocha
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Benjamin W Stein
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
| | - Jennifer N Wacker
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA. .,Department of Chemistry, Georgetown University, 37th and O Streets NW, Washington, D.C. 20057, USA
| | - Ping Yang
- Los Alamos National Laboratory (LANL), P.O. Box 1663, Los Alamos, New Mexico, 87545, USA.
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13
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Chen Y, Yang Q, Peng G, Zhang YQ, Ren XM. Influence of F-position and solvent on coordination geometry and single ion magnet behavior of Co(II) complexes. Dalton Trans 2021; 50:13830-13840. [PMID: 34522941 DOI: 10.1039/d1dt02148f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Three mononuclear Co(II) complexes with the compositions of [Co(L1)2] (1), [Co(L2)2(CH3CN)] (2) and [Co(L3)2] (3) (HL1 = 2-((E)-(2-fluorobenzylimino)methyl)-4,6-dibromophenol, HL2 = 2-((E)-(3-fluorobenzylimino)methyl)-4,6-dibromophenol and HL3 = 2-((E)-(4-fluorobenzylimino)methyl)-4,6-dibromophenol) were prepared and structurally determined. The changes in the F-positions in the ligands and solvents led to the formation of these products with various coordination geometries. Both complexes 1 and 3 are four-coordinated and their coordination geometries can be described as tetrahedron and seesaw, whereas complex 2 is five coordinated with a coordination configuration in between trigonal bipyramid and square pyramid. Static magnetic studies reveal that all these complexes exhibit considerable easy-axis magnetic anisotropy. The easy-axis magnetic anisotropy of 1 and 3 mainly derives from the first quartet excited state, whereas that of 2 primarily originates from the first, third and fourth quartet excited states established by theoretical calculations. All the resulting complexes display field-induced slow magnetic relaxation. Complex 3 represents the first Co(II) single ion magnet with a seesaw coordination geometry. Ab initio calculations predict that the magnetic anisotropy will enhance when the seesaw coordination geometry varies from distortion to regulation.
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Affiliation(s)
- Yue Chen
- School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, P. R. China.
| | - Qi Yang
- School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, P. R. China.
| | - Guo Peng
- School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, P. R. China.
| | - Yi-Quan Zhang
- Jiangsu Key Laboratory for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing 210023, P. R. China.
| | - Xiao-Ming Ren
- School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, P. R. China.
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14
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Alessio M, Krylov AI. Equation-of-Motion Coupled-Cluster Protocol for Calculating Magnetic Properties: Theory and Applications to Single-Molecule Magnets. J Chem Theory Comput 2021; 17:4225-4241. [PMID: 34191507 DOI: 10.1021/acs.jctc.1c00430] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
We present a new computational protocol for computing macroscopic magnetic properties of transition-metal complexes using the equation-of-motion coupled-cluster (EOM-CC) framework. The approach follows a two-step state-interaction scheme: we first compute zero-order states using nonrelativistic EOM-CC and then use these states to evaluate matrix elements of the spin-orbit and Zeeman operators. Diagonalization of the resulting Hamiltonian yields spin-orbit- and field-perturbed eigenstates. Temperature- and field-dependent magnetization and susceptibility are computed by numerical differentiation of the partition function. To compare with powder-sample experiments, these quantities are numerically averaged over field orientations. We applied this protocol to several single-molecule magnets (SMMs) with Fe(II) and Fe(III) in trigonal pyramidal, linear, and trigonal bipyramidal coordination environments. We described the underlying electronic structure by the electron-attachment (EOM-EA) and spin-flip (EOM-SF) variants of EOM-CC. The computed energy barriers for spin inversion, and macroscopic magnetization and susceptibility agree well with experimental data. Trends in magnetic anisotropy and spin-reversal energy barriers are explained in terms of a molecular orbital picture rigorously distilled from spinless transition density matrices between many-body states. The results illustrate excellent performances of EOM-CC in describing magnetic behavior of mononuclear transition-metal SMMs.
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Affiliation(s)
- Maristella Alessio
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Anna I Krylov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
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15
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Wang JH, Li ZY, Yamashita M, Bu XH. Recent progress on cyano-bridged transition-metal-based single-molecule magnets and single-chain magnets. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2020.213617] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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16
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Świtlicka A, Machura B, Cano J, Lloret F, Julve M. A Study of the Lack of Slow Magnetic Relaxation in Mononuclear Trigonal Bipyramidal Cobalt(II) Complexes. ChemistrySelect 2021. [DOI: 10.1002/slct.202100061] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Anna Świtlicka
- Department Of Crystallography, Institute of Chemistry University of Silesia 9th Szkolna St., 40–006 Katowice Poland
| | - Barbara Machura
- Department Of Crystallography, Institute of Chemistry University of Silesia 9th Szkolna St., 40–006 Katowice Poland
| | - Joan Cano
- Department of Química Inorgànica/Instituto de Ciencia Molecular (ICMol) Facultat de Quimica de la Universitat de València C/ Catedrático Jose Beltrán 2 46980 Paterna, València Spain
| | - Francesc Lloret
- Department of Química Inorgànica/Instituto de Ciencia Molecular (ICMol) Facultat de Quimica de la Universitat de València C/ Catedrático Jose Beltrán 2 46980 Paterna, València Spain
| | - Miguel Julve
- Department of Química Inorgànica/Instituto de Ciencia Molecular (ICMol) Facultat de Quimica de la Universitat de València C/ Catedrático Jose Beltrán 2 46980 Paterna, València Spain
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17
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Bhanja A, Smythe L, Herchel R, Nemec I, Murrie M, Ray D. Hydroxido supported and differently networked octanuclear Ni6Ln2 [Ln = GdIII and DyIII] complexes: structural variation, magnetic properties and theoretical insights. Dalton Trans 2021; 50:5023-5035. [DOI: 10.1039/d0dt04168h] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Solvent derived hydroxido bridge driven Ni6Ln2 [Ln = GdIII (1) and DyIII (2)] coordination aggregates of two different types has been synthesized. Magnetic susceptibility study confirms field induced slow relaxation of magnetization for Ni6Dy2.
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Affiliation(s)
- Avik Bhanja
- Department of Chemistry
- Indian Institute of Technology
- Kharagpur 721302
- India
| | - Lucy Smythe
- School of Chemistry
- University of Glasgow
- University Avenue
- Glasgow G12 8QQ
- UK
| | - Radovan Herchel
- Department of Inorganic Chemistry
- Faculty of Science
- Palacky University
- CZ-771 46 Olomouc
- Czech Republic
| | - Ivan Nemec
- Department of Inorganic Chemistry
- Faculty of Science
- Palacky University
- CZ-771 46 Olomouc
- Czech Republic
| | - Mark Murrie
- School of Chemistry
- University of Glasgow
- University Avenue
- Glasgow G12 8QQ
- UK
| | - Debashis Ray
- Department of Chemistry
- Indian Institute of Technology
- Kharagpur 721302
- India
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18
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Kumar P, SantaLucia DJ, Kaniewska-Laskowska K, Lindeman SV, Ozarowski A, Krzystek J, Ozerov M, Telser J, Berry JF, Fiedler AT. Probing the Magnetic Anisotropy of Co(II) Complexes Featuring Redox-Active Ligands. Inorg Chem 2020; 59:16178-16193. [DOI: 10.1021/acs.inorgchem.0c01812] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Praveen Kumar
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
| | - Daniel J. SantaLucia
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Kinga Kaniewska-Laskowska
- Department of Inorganic Chemistry, Faculty of Chemistry, Gdańsk University of Technology, Gdańsk PL-80-233, Poland
| | - Sergey V. Lindeman
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - J. Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Mykhaylo Ozerov
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Joshua Telser
- Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605, United States
| | - John F. Berry
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Adam T. Fiedler
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
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19
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Cui HH, Ding MM, Zhang XD, Lv W, Zhang YQ, Chen XT, Wang Z, Ouyang ZW, Xue ZL. Magnetic anisotropy in square pyramidal cobalt(II) complexes supported by a tetraazo macrocyclic ligand. Dalton Trans 2020; 49:14837-14846. [PMID: 33034595 DOI: 10.1039/d0dt01954b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two five-coordinate mononuclear Co(ii) complexes [Co(12-TMC)X][B(C6H5)4] (L = 1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecane (12-TMC), X = Cl- (1), Br- (2)) have been studied by X-ray single crystallography, magnetic measurements, high-frequency and -field EPR (HF-EPR) spectroscopy and theoretical calculations. Both complexes have a distorted square pyramidal geometry with the Co(ii) ion lying above the basal plane constrained by the rigid tetradentate macrocyclic ligand. In contrast to the reported five-coordinate Co(ii) complex [Co(12-TMC)(NCO)][B(C6H5)4] (3) exhibiting easy-axis anisotropy, an easy-plane magnetic anisotropy was found for 1 and 2via the analyses of the direct-current magnetic data and HF-EPR spectroscopy. Frequency- and temperature-dependent alternating-current magnetic susceptibility measurements demonstrated that complexes 1 and 2 show slow magnetic relaxation at an applied dc field. Ab initio calculations were performed to reveal the impact of the terminal ligands on the nature of the magnetic anisotropies of this series of five-coordinate Co(ii) complexes.
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Affiliation(s)
- Hui-Hui Cui
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
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20
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Sarkar A, Dey S, Rajaraman G. Role of Coordination Number and Geometry in Controlling the Magnetic Anisotropy in Fe II , Co II , and Ni II Single-Ion Magnets. Chemistry 2020; 26:14036-14058. [PMID: 32729641 DOI: 10.1002/chem.202003211] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Indexed: 12/22/2022]
Abstract
Since the last decade, the focus in the area of single-molecule magnets (SMMs) has been shifting constructively towards the development of single-ion magnets (SIMs) based on transition metals and lanthanides. Although ground-breaking results have been witnessed for DyIII -based SIMs, significant results have also been obtained for some mononuclear transition metal SIMs. Among others, studies based on CoII ion are very prominent as they often exhibit high magnetic anisotropy or zero-field splitting parameters and offer a large barrier height for magnetisation reversal. Although CoII possibly holds the record for having the largest number of zero-field SIMs known for any transition metal ion, controlling the magnetic anisotropy in these systems are is still a challenge. In addition to the modern spectroscopic techniques, theoretical studies, especially ab initio CASSCF/NEVPT2 approaches, have been used to uncover the electronic structure of various CoII SIMs. In this article, with some selected examples, the aim is to showcase how varying the coordination number from two to eight, and the geometry around the CoII centre alters the magnetic anisotropy. This offers some design principles for the experimentalists to target new generation SIMs based on the CoII ion. Additionally, some important FeII /FeIII and NiII complexes exhibiting large magnetic anisotropy and SIM properties are also discussed.
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Affiliation(s)
- Arup Sarkar
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - Sourav Dey
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India
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21
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Wang Y, Yuan Z, Guo Y, Ma X, Meng Z, Sha J, Zhang H. Single‐Molecule Magnetism in Dy
2
Cluster Based on a Schiff Base Ligand. Z Anorg Allg Chem 2020. [DOI: 10.1002/zaac.202000089] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Yingying Wang
- Department of Chemistry and Chemical Engineering Key Laboratory of Inorganic Chemistry in Universities of Shandong Jining University 273155 Qufu P. R. China
| | - Zhuangdong Yuan
- Department of Chemistry and Chemical Engineering Key Laboratory of Inorganic Chemistry in Universities of Shandong Jining University 273155 Qufu P. R. China
| | - Yunjie Guo
- Department of Chemistry and Chemical Engineering Key Laboratory of Inorganic Chemistry in Universities of Shandong Jining University 273155 Qufu P. R. China
| | - Xuxiao Ma
- Department of Chemistry and Chemical Engineering Key Laboratory of Inorganic Chemistry in Universities of Shandong Jining University 273155 Qufu P. R. China
| | - Zitong Meng
- Department of Chemistry and Chemical Engineering Key Laboratory of Inorganic Chemistry in Universities of Shandong Jining University 273155 Qufu P. R. China
| | - Jingquan Sha
- Department of Chemistry and Chemical Engineering Key Laboratory of Inorganic Chemistry in Universities of Shandong Jining University 273155 Qufu P. R. China
| | - Haifeng Zhang
- Department of Chemistry and Chemical Engineering Key Laboratory of Inorganic Chemistry in Universities of Shandong Jining University 273155 Qufu P. R. China
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22
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Peng G, Chen Y, Li B, Zhang YQ, Ren XM. Bulky Schiff-base ligand supported Co(ii) single-ion magnets with zero-field slow magnetic relaxation. Dalton Trans 2020; 49:5798-5802. [PMID: 32338258 DOI: 10.1039/d0dt00790k] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two mononuclear Co(ii) complexes with tetrahedral coordination geometry have been constructed from different bulky Schiff-base ligands. Both complexes exhibit slow magnetic relaxation without a static field and their relaxation behaviors can be tuned by ligand substitution. Clear magnetic hysteresis loops were observed for both complexes at 2 K.
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Affiliation(s)
- Guo Peng
- School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, P. R. China.
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23
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Huang XC, Li JX, Chen YZ, Wang WY, Xu R, Tao JX, Shao D, Zhang YQ. Tuning Magnetic Anisotropy in a Class of Co(II) Bis(hexafluoroacetylacetonate) Complexes. Chem Asian J 2020; 15:1469-1477. [PMID: 32202396 DOI: 10.1002/asia.201901625] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 03/21/2020] [Indexed: 11/10/2022]
Abstract
Tuning the magnetic anisotropy of metal ions remains highly interesting in the design of improved single-molecule magnets (SMMs). We herein report synthetic, structural, magnetic, and computational studies of four mononuclear CoII complexes, namely [Co(hfac)2 (MeCN)2 ] (1), [Co(hfac)2 (Spy)2 ] (2), [Co(hfac)2 (MBIm)2 ] (3), and [Co(hfac)2 (DMF)2 ] (4) (MeCN=acetonitrile, hfac=hexafluoroacetylacetone, Spy=4-styrylpyridine, MbIm=5,6-dimethylbenzimidazole, DMF=N,N-dimethylformamide), with distorted octahedral geometry constructed from hexafluoroacetylacetone (hfac) and various axial ligands. By a building block approach, complexes 2-4 were synthesized by recrystallization of the starting material of 1 from various ligands containing solution. Magnetic and theoretical studies reveal that 1-4 possess large positive D values and relative small E parameters, indicating easy-plane magnetic anisotropy with significant rhombic anisotropy in 1-4. Dynamic alternative current (ac) magnetic susceptibility measurements indicate that these complexes exhibit slow magnetic relaxation under external fields, suggesting field-induced single-ion magnets (SIMs) of 1-4. These results provide a promising platform to achieve fine tuning of magnetic anisotropy through varying the axial ligands based on Co(II) bis(hexafluoroacetylacetonate) complexes.
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Affiliation(s)
- Xing-Cai Huang
- School of Chemistry and Environmental Engineering, Yancheng Teachers University, Yancheng, 224007, China
| | - Jia-Xin Li
- Jiangsu Key Lab for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing, 210023, China
| | - Yong-Zhi Chen
- School of Chemistry and Environmental Engineering, Yancheng Teachers University, Yancheng, 224007, China
| | - Wen-Yan Wang
- School of Chemistry and Environmental Engineering, Yancheng Teachers University, Yancheng, 224007, China
| | - Rui Xu
- School of Chemistry and Environmental Engineering, Yancheng Teachers University, Yancheng, 224007, China
| | - Jin-Xia Tao
- School of Chemistry and Environmental Engineering, Yancheng Teachers University, Yancheng, 224007, China
| | - Dong Shao
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Yi-Quan Zhang
- Jiangsu Key Lab for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing, 210023, China
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24
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Hu ZB, Feng X, Li J, Zhang YQ, Yin L, Wang Z, Ouyang Z, Kurmoo M, Song Y. Optimal diamagnetic dilution concentration for suppressing the dipole-dipole interaction in single-ion magnets. Dalton Trans 2020; 49:2159-2167. [PMID: 31994553 DOI: 10.1039/c9dt04403e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The effect of screening the CoII moment of monomeric [CoIIL2(H2O)] (L = 8-hydroxyquinaldine), having a trigonal bipyramid coordination, by diamagnetic Zn in CoxZn1-x solid solutions on its magnetic relaxation was explored using ac-susceptibility, high-field electron-spin-resonance measurements and CASPT2 calculations. The retention of the crystal structure for all the solid solutions was demonstrated using single crystal diffraction. The dc-magnetization and theoretical fittings of the susceptibility for Co1 and Co0.1Zn0.9 gave a large zero-field-splitting (ZFS) D of 50 ± 6 cm-1, and very weak dipole interaction between the nearest neighbors, while EPR and calculations confirmed the positive sign of the axial component (D). Consistent parameters were obtained from experiments and theory. Importantly, only field-induced relaxation was observed for the samples with less than 50% Co and a gradual change in the barrier energy to moment reversal and relaxation times was observed between 11% and 20% Co, while both were enhanced for higher dilutions. The results establish a clear barrier for extending the longevity of the magnetism for this type of single-ion species by lowering the intramolecular interactions. The results suggest that the magnetic interaction persists up to the second sphere, that is, for a dilution of 1 in 9 (11% Co). Importantly, this method is applicable to all single-ion magnet systems, that is, the optimum dilution concentration to restrain the dipole field can be given only by the single crystal structure.
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Affiliation(s)
- Zhao-Bo Hu
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
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25
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Hay MA, Sarkar A, Craig GA, Marriott KER, Wilson C, Rajaraman G, Murrie M. A large axial magnetic anisotropy in trigonal bipyramidal Fe(ii). Chem Commun (Camb) 2020; 56:6826-6829. [DOI: 10.1039/d0cc02382e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Minimising geometric distortion in the first coordination sphere generates a large axial magnetic anisotropy in trigonal bipyramidal Fe(ii) and rare slow magnetic relaxation.
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Affiliation(s)
- Moya A. Hay
- School of Chemistry
- University of Glasgow
- Glasgow
- UK
| | - Arup Sarkar
- Department of Chemistry
- Institute of Technology Bombay
- Mumbai
- India
| | | | | | | | | | - Mark Murrie
- School of Chemistry
- University of Glasgow
- Glasgow
- UK
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26
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Singh MK, Shukla P, Khatua M, Rajaraman G. A Design Criteria to Achieve Giant Ising-Type Anisotropy in Co II -Encapsulated Metallofullerenes. Chemistry 2019; 26:464-477. [PMID: 31506987 DOI: 10.1002/chem.201903618] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/05/2019] [Indexed: 11/10/2022]
Abstract
Discovery of permanent magnetisation in molecules just like in hard magnets decades ago led to the proposal of utilising these molecules for information storage devices and also as Q-bits in quantum computing. A significant breakthrough with a blocking temperature as high as 80 K has been recently reported for lanthanocene complexes. While enhancing the blocking temperature further remains one of the primary challenges, obtaining molecules that are suitable for the fabrication of the devices sets the bar very high in this area. Encouraged by the fact that our earlier predictions of potential single-molecule magnets (SMMs) in lanthanide-containing endohedral fullerenes have been verified, here we set out to undertake a comprehensive study on CoII -ion-encapsulated fullerene as potential SMMs. To study this class of molecules, we have utilised an array of theoretical methods ranging from density functional to ab initio CASSCF/NEVPT2 methods for obtaining reliable estimate of zero-field splitting parameters D and E. Additionally, we have also employed, for the first time a combination of molecular dynamics based on DFT methods coupled with CASSCF/NEVPT2 methods to seek the role of conformational isomers in the relaxation of magnetisation. Particularly, we have studied, Co@C28 , Co@C38 and Co@C48 cages and their isomers as potential target molecules that could yield substantial magnetic anisotropy. Our calculations categorically reveal a very large Ising anisotropy in this class of molecules, with Co@C48 cages predicted to yield D values as high as -127 cm-1 . Our calculations on the smaller cages reveal the free movement of CoII ion inside the cage, leading to the likely scenario of faster relaxation of magnetisation. However, larger fullerene cages were found to solve this issue. Further models with incorporating units such as {CoOZn}, {CoScZnN} inside larger fullerenes yield axial zero-field splitting values as high as -200 cm-1 with negligible E/D values. As these units represent a strong axiality coupled with a viable way to obtain air-stable low-coordinate CoII complexes, this opens up a new paradigm in the search of SMMs in this class of molecules.
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Affiliation(s)
- Mukesh Kumar Singh
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Pratima Shukla
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Munmun Khatua
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
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27
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Ma D, Peng G, Zhang YY, Li B. Field-induced slow magnetic relaxation in two-dimensional and three-dimensional Co(ii) coordination polymers. Dalton Trans 2019; 48:15529-15536. [PMID: 31314024 DOI: 10.1039/c9dt02070e] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two coordination polymers formulated as [Co(1,4-bimb)0.5(5-aip)(H2O)]n (1) and [Co(1,4-bib)1.5(5-hip)(H2O)]n (2) (1,4-bimb = 1,4-bis(imidazol-1-ylmethyl)benzene, 5-aip = 5-aminoisophthalic acid, 1,4-bib = 1,4-bis(1-imidazolyl)benzene and 5-hip = 5-hydroxyisophthalic acid) have been prepared and structurally characterized. Complex 1 is a two-dimensional (2D) network where Co(ii) is six coordinate in a CoO4N2 coordination environment, while the structure of 2 consists of a three-dimensional (3D) framework built from mononuclear Co(ii) units with distorted octahedral geometry as nodes. Static magnetic studies show that first-order orbital angular momentum may play an important role in the magnetic properties of 1, whereas strong easy-axis anisotropy (D = -102 cm-1) was observed in 2. Alternating current (ac) susceptibility measurements demonstrate that both the complexes display field-induced single ion magnet (SIM) behavior.
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Affiliation(s)
- Deyun Ma
- School of Food and Pharmaceutical Engineering, Zhaoqing University, Zhaoqing 526061, P. R. China
| | - Guo Peng
- College of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, P. R. China. and Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, P. R. China.
| | - Ying-Ying Zhang
- Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, P. R. China.
| | - Bo Li
- College of Chemistry and Pharmaceutical Engineering, Nanyang Normal University, Nanyang 473061, P. R. China.
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28
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Single‐Molecule Magnetism in Three Dy
2
Complexes from the Use of a Pentadentate Schiff Base Ligand and Different Benzoates. Chem Asian J 2019; 14:2846-2852. [DOI: 10.1002/asia.201900636] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 06/19/2019] [Indexed: 01/13/2023]
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29
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Hay MA, McMonagle CJ, Wilson C, Probert MR, Murrie M. Trigonal to Pentagonal Bipyramidal Coordination Switching in a Co(II) Single-Ion Magnet. Inorg Chem 2019; 58:9691-9697. [DOI: 10.1021/acs.inorgchem.9b00515] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Moya A. Hay
- WestCHEM, School of Chemistry, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - Charles J. McMonagle
- Chemistry, School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom
| | - Claire Wilson
- WestCHEM, School of Chemistry, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - Michael R. Probert
- Chemistry, School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom
| | - Mark Murrie
- WestCHEM, School of Chemistry, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
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30
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Hay MA, Sarkar A, Craig GA, Bhaskaran L, Nehrkorn J, Ozerov M, Marriott KER, Wilson C, Rajaraman G, Hill S, Murrie M. In-depth investigation of large axial magnetic anisotropy in monometallic 3d complexes using frequency domain magnetic resonance and ab initio methods: a study of trigonal bipyramidal Co(ii). Chem Sci 2019; 10:6354-6361. [PMID: 31341591 PMCID: PMC6601423 DOI: 10.1039/c9sc00987f] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 05/19/2019] [Indexed: 11/21/2022] Open
Abstract
The magnetic properties of 3d monometallic complexes can be tuned through geometric control, owing to their synthetic accessibility and relative structural simplicity. Monodentate ligands offer great potential for fine-tuning the coordination environment to engineer both the axial and rhombic zero-field splitting (ZFS) parameters. In [CoCl3(DABCO)(HDABCO)] (1), the trigonal bipyramidal Co(ii) centre has two bulky axial ligands and three equatorial chloride ligands. An in-depth experimental and theoretical study of 1 reveals a large easy-plane magnetic anisotropy (+ve D) with a negligible rhombic zero-field splitting (E) due to the strict axial symmetry imposed by the C 3 symmetric ligand and trigonal space group. The large easy-plane magnetic anisotropy (D = +44.5 cm-1) is directly deduced using high-field EPR and frequency-domain magnetic resonance (FDMR) studies. Ab initio calculations reveal a large positive contribution to the D term arising from ground state/excited state mixing of the 4E'' states at ∼4085 cm-1 and a minor contribution from the spin-flip transition as well. The nature of the slow relaxation in 1 is elucidated through analysis of the rates of relaxation of magnetisation, taking into account Raman and direct spin-lattice relaxation processes and Quantum Tunnelling of the Magnetisation (QTM). The terms relating to the direct process and QTM were found based on the fit of the field-dependence of τ at 2 K. Subsequently, these were used as fixed parameters in the fit of the temperature-dependence of τ to obtain the Raman terms. This experimental-theoretical investigation provides further insight into the power of FDMR and ab initio methods for the thorough investigation of magnetic anisotropy. Thus, these results contribute to design criteria for high magnetic anisotropy systems.
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Affiliation(s)
- Moya A Hay
- WestCHEM , School of Chemistry , University of Glasgow , University Avenue , Glasgow , G12 8QQ , UK .
| | - Arup Sarkar
- Department of Chemistry , Institute of Technology Bombay , Powai , Mumbai , Maharashtra 400 076 , India .
| | - Gavin A Craig
- WestCHEM , School of Chemistry , University of Glasgow , University Avenue , Glasgow , G12 8QQ , UK .
| | - Lakshmi Bhaskaran
- Department of Physics , Florida State University , Tallahassee , FL 32306 , USA .
- National High Magnetic Field Laboratory , 1800 E. Paul Dirac Drive Tallahassee , FL 32310 , USA
| | - Joscha Nehrkorn
- National High Magnetic Field Laboratory , 1800 E. Paul Dirac Drive Tallahassee , FL 32310 , USA
- Max Planck Institute for Chemical Energy Conversion , Stiftstr. 34-36 , 45470 Mülheim an der Ruhr , Germany
| | - Mykhailo Ozerov
- National High Magnetic Field Laboratory , 1800 E. Paul Dirac Drive Tallahassee , FL 32310 , USA
| | - Katie E R Marriott
- WestCHEM , School of Chemistry , University of Glasgow , University Avenue , Glasgow , G12 8QQ , UK .
| | - Claire Wilson
- WestCHEM , School of Chemistry , University of Glasgow , University Avenue , Glasgow , G12 8QQ , UK .
| | - Gopalan Rajaraman
- Department of Chemistry , Institute of Technology Bombay , Powai , Mumbai , Maharashtra 400 076 , India .
| | - Stephen Hill
- Department of Physics , Florida State University , Tallahassee , FL 32306 , USA .
- National High Magnetic Field Laboratory , 1800 E. Paul Dirac Drive Tallahassee , FL 32310 , USA
| | - Mark Murrie
- WestCHEM , School of Chemistry , University of Glasgow , University Avenue , Glasgow , G12 8QQ , UK .
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31
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Chen Q, Fan S, Taddei KM, Stone MB, Kolesnikov AI, Cheng J, Musfeldt JL, Zhou H, Aczel AA. Large Positive Zero-Field Splitting in the Cluster Magnet Ba3CeRu2O9. J Am Chem Soc 2019; 141:9928-9936. [DOI: 10.1021/jacs.9b03389] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | - Keith M. Taddei
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Matthew B. Stone
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Alexander I. Kolesnikov
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Jinguang Cheng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | | | | | - Adam A. Aczel
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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32
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Wang HS, Chen Y, Hu ZB, Yin CL, Zhang Z, Pan ZQ. Modulation of the directions of the anisotropic axes of DyIII ions through utilizing two kinds of organic ligands or replacing DyIII ions by FeIII ions. CrystEngComm 2019. [DOI: 10.1039/c9ce00894b] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two complexes based on Dy4 or Fe2Dy2 tetrahedral unit have been obtained by employing mixed organic ligands. The directions of the easy magnetization for the DyIII in both complexes were successfully modulated.
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Affiliation(s)
- Hui-Sheng Wang
- School of Chemistry and Environmental Engineering
- Key Laboratory of Green Chemical Process of Ministry of Education
- Wuhan Institute of Technology
- Wuhan 430074
- P. R. China
| | - Yong Chen
- School of Chemistry and Environmental Engineering
- Key Laboratory of Green Chemical Process of Ministry of Education
- Wuhan Institute of Technology
- Wuhan 430074
- P. R. China
| | - Zhao-Bo Hu
- State Key Laboratory of Coordination Chemistry
- School of Chemistry and Chemical Engineering
- Collaborative Innovation Center of Advanced Microstructures
- Nanjing University
- Nanjing 210046
| | - Cheng-Ling Yin
- School of Chemistry and Environmental Engineering
- Key Laboratory of Green Chemical Process of Ministry of Education
- Wuhan Institute of Technology
- Wuhan 430074
- P. R. China
| | - Zaichao Zhang
- Jiangsu Key Laboratory for the Chemistry of Low-dimensional Materials
- School of Chemistry and Chemical Engineering
- Huaiyin Normal University
- Huaiyin 223300
- P. R. China
| | - Zhi-Quan Pan
- School of Chemistry and Environmental Engineering
- Key Laboratory of Green Chemical Process of Ministry of Education
- Wuhan Institute of Technology
- Wuhan 430074
- P. R. China
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