51
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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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52
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Yang Q, Wang GL, Zhang YQ, Tang J. Self-assembly of fish-bone and grid-like Co II-based single-molecule magnets using dihydrazone ligands with NNN and NNO pockets. Dalton Trans 2022; 51:13928-13937. [PMID: 36040449 DOI: 10.1039/d2dt02451a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Three CoII complexes, [Co2(H2L1)2](ClO4)4·4CH3OH (1), [Co2(H4L2)2](ClO4)4 (2) and [Co4(H4L2)4](ClO4)8 (3), were constructed by the self-assembly of the symmetrical dihydrazone ligands H2L1 and H4L2 with CoII ions under different synthetic conditions. The fish-bone-like complex 1 was obtained using the ligand H2L1 in methanol via the solvothermal method, while the self-assembly of H4L2 with CoII ions is solvent-dependent, producing the fish-bone-like complex 2 and [2 × 2] grid-like complex 3. Magnetic susceptibility measurements and theoretical calculations reveal that the large negative D values for the three complexes stem from their easy-axis magnetic anisotropy. Ac magnetic susceptibility measurements disclosed field-induced slow magnetic relaxation behaviors and the presence of Raman and/or direct processes of the three complexes at various applied dc fields.
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Affiliation(s)
- Qianqian Yang
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China. .,School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, P. R. China
| | - Guo-Lu Wang
- Jiangsu Key Lab for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing 210023, P. R. China
| | - Yi-Quan Zhang
- Jiangsu Key Lab 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. .,School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, P. R. China
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53
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Gil Y, Castro-Alvarez A, Fuentealba P, Spodine E, Aravena D. Lanthanide SMMs Based on Belt Macrocycles: Recent Advances and General Trends. Chemistry 2022; 28:e202200336. [PMID: 35648577 DOI: 10.1002/chem.202200336] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Indexed: 11/06/2022]
Abstract
Enhancement of axial magnetic anisotropy is the central objective to push forward the performance of Single-Molecule Magnet (SMM) complexes. In the case of mononuclear lanthanide complexes, the chemical environment around the paramagnetic ion must be tuned to place strongly interacting ligands along either the axial positions or the equatorial plane, depending on the oblate or prolate preference of the selected lanthanide. One classical strategy to achieve a precise chemical environment for a metal centre is using highly structured, chelating ligands. A natural approach for axial-equatorial control is the employment of macrocycles acting in a belt conformation, providing the equatorial coordination environment, and leaving room for axial ligands. In this review, we present a survey of SMMs based on the macrocycle belt motif. Literature systems are divided in three families (crown ether, Schiff-base and metallacrown) and their general properties in terms of structural stability and SMM performance are briefly discussed.
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Affiliation(s)
- Yolimar Gil
- Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Casilla 233, Santiago, Chile.,Centro para la Nanociencia y Nanotecnología (CEDENNA), Santiago, Estación Central, Región Metropolitana, Chile
| | - Alejandro Castro-Alvarez
- Departamento de Química de los Materiales, Facultad de Química y Biología, Universidad de Santiago de Chile, Casilla 40, Correo 33, Santiago, Chile
| | - Pablo Fuentealba
- Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Casilla 233, Santiago, Chile
| | - Evgenia Spodine
- Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Casilla 233, Santiago, Chile.,Centro para la Nanociencia y Nanotecnología (CEDENNA), Santiago, Estación Central, Región Metropolitana, Chile
| | - Daniel Aravena
- Departamento de Química de los Materiales, Facultad de Química y Biología, Universidad de Santiago de Chile, Casilla 40, Correo 33, Santiago, Chile
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54
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Martín-Fuentes C, Parreiras SO, Urgel JI, Rubio-Giménez V, Muñiz Cano B, Moreno D, Lauwaet K, Valvidares M, Valbuena MA, Gargiani P, Kuch W, Camarero J, Gallego JM, Miranda R, Martínez JI, Martí-Gastaldo C, Écija D. On-Surface Design of a 2D Cobalt-Organic Network Preserving Large Orbital Magnetic Moment. J Am Chem Soc 2022; 144:16034-16041. [PMID: 36007260 DOI: 10.1021/jacs.2c05894] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The design of antiferromagnetic nanomaterials preserving large orbital magnetic moments is important to protect their functionalities against magnetic perturbations. Here, we exploit an archetype H6HOTP species for conductive metal-organic frameworks to design a Co-HOTP one-atom-thick metal-organic architecture on a Au(111) surface. Our multidisciplinary scanning probe microscopy, X-ray absorption spectroscopy, X-ray linear dichroism, and X-ray magnetic circular dichroism study, combined with density functional theory simulations, reveals the formation of a unique network design based on threefold Co+2 coordination with deprotonated ligands, which displays a large orbital magnetic moment with an orbital to effective spin moment ratio of 0.8, an in-plane easy axis of magnetization, and large magnetic anisotropy. Our simulations suggest an antiferromagnetic ground state, which is compatible with the experimental findings. Such a Co-HOTP metal-organic network exemplifies how on-surface chemistry can enable the design of field-robust antiferromagnetic materials.
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Affiliation(s)
- Cristina Martín-Fuentes
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanoscience), E-28049 Madrid, Spain
| | - Sofia O Parreiras
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanoscience), E-28049 Madrid, Spain
| | - José I Urgel
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanoscience), E-28049 Madrid, Spain
| | - Víctor Rubio-Giménez
- Instituto de Ciencia Molecular (ICMol), Universitat de València, 46980 Paterna, Spain
| | - Beatriz Muñiz Cano
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanoscience), E-28049 Madrid, Spain
| | - Daniel Moreno
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanoscience), E-28049 Madrid, Spain
| | - Koen Lauwaet
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanoscience), E-28049 Madrid, Spain
| | | | - Miguel A Valbuena
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanoscience), E-28049 Madrid, Spain
| | | | - Wolfgang Kuch
- Institut für Experimentalphysik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Julio Camarero
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanoscience), E-28049 Madrid, Spain.,Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
| | - José M Gallego
- Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Cantoblanco, 28049 Madrid, Spain
| | - Rodolfo Miranda
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanoscience), E-28049 Madrid, Spain.,Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
| | - José I Martínez
- Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Cantoblanco, 28049 Madrid, Spain
| | - Carlos Martí-Gastaldo
- Instituto de Ciencia Molecular (ICMol), Universitat de València, 46980 Paterna, Spain
| | - David Écija
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanoscience), E-28049 Madrid, Spain
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55
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Wen GH, Zou Q, Xu K, Huang XD, Bao SS, Chen XT, Ouyang Z, Wang Z, Zheng LM. Layered Uranyl Phosphonates Encapsulating Co(II)/Mn(II)/Zn(II) Ions: Exfoliation into Nanosheets and Its Impact on Magnetic and Luminescent Properties. Chemistry 2022; 28:e202200721. [PMID: 35570193 DOI: 10.1002/chem.202200721] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Indexed: 01/17/2023]
Abstract
Layered heterometallic 5f-3d uranyl phosphonates can exhibit unique luminescent and/or magnetic properties, but the fabrication and properties of their 2D counterparts have not been investigated. Herein we report three heterobimetallic uranyl phosphonates, namely, [(UO2 )3 M(2-pmbH)4 (H2 O)4 ] ⋅ 2H2 O [MU, M=Co(II), CoU; Mn(II), MnU; Zn(II), ZnU; 2-pmbH3 =2-(phosphonomethyl)benzoic acid]. They are isostructural and display two-dimensional layered structures where the M(II) centers are encapsulated inside the windows generated by the diamagnetic uranyl phosphonate layer. Each M(II) has an octahedral geometry filled with four water molecules in the equatorial positions and two phosphonate oxygen atoms in the axial positions. The uranium atoms adopt UO7 pentagonal bipyramidal and UO6 square bipyramidal geometries. The lattice and coordination water molecules can be released by thermal treatment and reabsorbed in a reversible manner, accompanied with changes of magnetic dynamics. Interestingly, the bulk samples of MU can be exfoliated in acetone via freezing and thawing processes forming nanosheets with single-layer or two-layer thickness (MU-ns). Magnetic studies revealed that the CoU and MnU systems exhibited field-induced slow magnetization relaxation at low temperature. Compared with crystalline CoU, the magnetic relaxation of the CoU-ns aggregates is significantly accelerated. Moreover, photoluminescence measured at 77 K showed slight red-shift of the five characteristic uranyl emission bands for ZnU-ns in comparison with those of the crystalline ZnU. This work gives the first examples of 2D materials based on 5f-3d heterometallic uranyl phosphonates and illustrates the impact of dimension reduction on their magnetic/optical properties.
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Affiliation(s)
- Ge-Hua Wen
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, China
| | - Qian Zou
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, China
| | - Kui Xu
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, China
| | - Xin-Da Huang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, China
| | - Song-Song Bao
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, China
| | - Xue-Tai Chen
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, China
| | - Zhongwen Ouyang
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Zhenxing Wang
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Li-Min Zheng
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, China
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56
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Yureva EA, Korchagin DV, Anichkin AA, Shilov GV, Babeshkin KA, Efimov NN, Palii AV, Aldoshin SM. Evidence for zero-field slow magnetic relaxation in a Co(II) complex with a pseudo-tetrahedral N 2I 2 environment. Dalton Trans 2022; 51:11916-11921. [PMID: 35876183 DOI: 10.1039/d2dt01336c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Herein, we report on the synthesis, structure and magnetic properties of a four-coordinate mononuclear Co(II) diiodide complex with the 3,5-dimethylpyrazole ligand. A distorted tetrahedral local coordination environment around the central cobalt ion is formed by the two nitrogen atoms of two monodentate pyrazole ligands and by iodide ions. Direct current (dc) magnetic measurements in combination with ab initio SA-CASSCF/NEVPT2 quantum-chemical calculations revealed a strong easy-axis-type magnetic anisotropy with a record value Dexp = -30.58(3) cm-1 of the axial zero field splitting parameter for pseudo-tetrahedral Co(II)-based CoL2Hal2 complexes. Moreover, it is the only complex in this series demonstrating the slow relaxation of magnetization at zero dc field. The Orbach process is shown to be the dominant mechanism of magnetic relaxations in the high temperature range, while the quantum tunneling of magnetization produces the leading contribution to the overall relaxation at temperatures below 4 K.
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Affiliation(s)
- E A Yureva
- Institute of Problems of Chemical Physics, Russian Academy of Sciences, 1, Acad. Semenov prosp., 142432 Chernogolovka, Moscow Region, Russia.
| | - D V Korchagin
- Institute of Problems of Chemical Physics, Russian Academy of Sciences, 1, Acad. Semenov prosp., 142432 Chernogolovka, Moscow Region, Russia.
| | - A A Anichkin
- Institute of Problems of Chemical Physics, Russian Academy of Sciences, 1, Acad. Semenov prosp., 142432 Chernogolovka, Moscow Region, Russia. .,Faculty of Fundamental Physical and Chemical Engineering, Moscow State University, 1-3, Leninskiye Gory, 119991 Moscow, Russia
| | - G V Shilov
- Institute of Problems of Chemical Physics, Russian Academy of Sciences, 1, Acad. Semenov prosp., 142432 Chernogolovka, Moscow Region, Russia.
| | - K A Babeshkin
- N. S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, 31, Leninsky prosp., 119991 Moscow, Russia
| | - N N Efimov
- N. S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, 31, Leninsky prosp., 119991 Moscow, Russia
| | - A V Palii
- Institute of Problems of Chemical Physics, Russian Academy of Sciences, 1, Acad. Semenov prosp., 142432 Chernogolovka, Moscow Region, Russia.
| | - S M Aldoshin
- Institute of Problems of Chemical Physics, Russian Academy of Sciences, 1, Acad. Semenov prosp., 142432 Chernogolovka, Moscow Region, Russia.
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57
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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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58
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Wang W, Shang T, Wang J, Yao BL, Li LC, Ma Y, Wang QL, Zhang YZ, Zhang YQ, Zhao B. Slow magnetic relaxation in a Dy 3 triangle and a bistriangular Dy 6 cluster. Dalton Trans 2022; 51:9404-9411. [PMID: 35674238 DOI: 10.1039/d1dt03414f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Two lanthanide single-molecule magnets (SMMs) [Dy3(μ3-OH)(HL-1)3(H2O)3](NO3)2·3H3O (1, H3L-1 = (E)-3-(((8-hydroxyquinolin-2-yl)methylene)amino)propane-1,2-diol) and [Dy6(μ3-OH)4(H2L-2)4(HL-2)2(L-2)2] (2, H3L-2 = (E)-2-hydroxy-N'-(2-hydroxy-3-methoxybenzylidene)benzohydrazide) were synthesized and characterized structurally and magnetically. Complex 1 contains a triangular Dy3 core in which the three Dy3+ ions share a μ3-OH- anion and the deprotonated ligands of (HL-1)2- serve both capping and bridging functions, while 2 displays a centrosymmetric hexanuclear DyIII structure with two similar Dy3 triangular cores ligated by two fully deprotonated (L-2)3- ligands, each of which shares two μ3-OH- anions. All the DyIII ions are eight-coordinated with quasi D2d or C2v symmetry. Magnetic studies reveal that 1 exhibited two-step magnetic relaxation under an applied dc field of 800 Oe, with effective energy barriers of 40.1 and 31.0 K for the slow relaxation (SR) and fast relaxation regimes (FR), respectively. Meanwhile, 2 only showed a tail of slow magnetic relaxation at above 2 K. Ab initio calculations have been carried out to show the nature of their different magnetic properties.
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Affiliation(s)
- Wen Wang
- Department of Chemistry and Key Laboratory of Advanced Energy Materials Chemistry (MOE) and TKL of Metal and Molecule Based Material Chemistry, Nankai University, Tianjin 300071, China.
| | - Tao Shang
- Jiangsu Key Lab for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing 210023, P. R. China.
| | - Juan Wang
- Department of Chemistry and Key Laboratory of Advanced Energy Materials Chemistry (MOE) and TKL of Metal and Molecule Based Material Chemistry, Nankai University, Tianjin 300071, China.
| | - Bin-Ling Yao
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055, P. R. China.
| | - Li-Cun Li
- Department of Chemistry and Key Laboratory of Advanced Energy Materials Chemistry (MOE) and TKL of Metal and Molecule Based Material Chemistry, Nankai University, Tianjin 300071, China.
| | - Yue Ma
- Department of Chemistry and Key Laboratory of Advanced Energy Materials Chemistry (MOE) and TKL of Metal and Molecule Based Material Chemistry, Nankai University, Tianjin 300071, China.
| | - Qing-Lun Wang
- Department of Chemistry and Key Laboratory of Advanced Energy Materials Chemistry (MOE) and TKL of Metal and Molecule Based Material Chemistry, Nankai University, Tianjin 300071, China.
| | - Yuan-Zhu Zhang
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055, P. R. China.
| | - Yi-Quan Zhang
- Jiangsu Key Lab for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing 210023, P. R. China.
| | - Bin Zhao
- Department of Chemistry and Key Laboratory of Advanced Energy Materials Chemistry (MOE) and TKL of Metal and Molecule Based Material Chemistry, Nankai University, Tianjin 300071, China.
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59
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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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60
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Ahmed N, Ansari KU. Zero-field slow magnetic relaxation behavior of Zn 2Dy in a family of trinuclear near-linear Zn 2Ln complexes: synthesis, experimental and theoretical investigations. Dalton Trans 2022; 51:8766-8776. [PMID: 35615914 DOI: 10.1039/d2dt00926a] [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
We hereby report a series of near-linear trinuclear [Zn2LnIII(HL)4(CH3COO)]·(NO3)2 (where LnIII = La (1-La), Ce (2-Ce), Nd (3-Nd), Sm (4-Sm), Tb (5-Tb), and Dy (6-Dy)) complexes with Schiff base ligand (H2L). Magnetization relaxation dynamic studies on complexes 2-Ce, 5-Tb, and 6-Dy reveal the existence of well resolved frequency dependent zero-field out-of-phase χ''M signals, which is an indicator of a typical single-ion magnet behavior observed only for complex 6-Dy with Ueff = 43.7 K (τ0 = 2.42 × 10-6 s). The presence of two Zn(II) ions near the coordination geometry of Dy(III) ion in 6-Dy is likely to keep the first excited mJ levels significantly away from the ground state mJ level and is responsible for the observation of zero field slow magnetic relaxation behavior. The data collected in the presence of a magnetic field of Hdc = 2 kOe enhances the energy barrier by two-fold (88.63 K, τ0 = 1.36 × 10-7 s) in 6-Dy, suggesting the presence of QTM at zero field along with other under barrier relaxations, such as the Raman process. On the other hand, complex 2-Ce shows field induced slow relaxation of magnetization behavior with an effective energy barrier of 12.24 K (τ0 = 1.89 × 10-4 s). The CASSCF/SO-RASSI/SINGLE_ANISO based ab initio calculations using MOLCAS 8.0 code further rationalized our experimentally observed magnetization dynamics.
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Affiliation(s)
- Naushad Ahmed
- Department of Chemistry, Indian Institute of Technology Bombay Powai, Mumbai-400076, Maharashtra, India.
| | - Kamal Uddin Ansari
- Department of Chemistry, Indian Institute of Technology Bombay Powai, Mumbai-400076, Maharashtra, India.
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61
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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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Ghosh S, Kamilya S, Mehta S, Herchel R, Kiskin M, Veber S, Fedin M, Mondal A. Effect of Ligand Chain Length for Tuning of Molecular Dimensionality and Magnetic Relaxation in Redox Active Cobalt(II) EDOT Complexes (EDOT = 3,4-Ethylenedioxythiophene). Chem Asian J 2022; 17:e202200404. [PMID: 35617522 DOI: 10.1002/asia.202200404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 05/17/2022] [Indexed: 11/07/2022]
Abstract
Four cobalt(II) complexes, [Co(L1)2(NCX)2(MeOH)2] (X = S (1), Se (2)) and {[Co(L2)2(NCX)2]}n (X = S (3), Se (4)) (L1 = 2,5dipyridyl-3,4,-ethylenedioxylthiophene and L2 = 2,5diethynylpyridinyl-3,4-ethylenedioxythiophene), were synthesized by incorporating ethylenedioxythiophene based redox-active luminescence ligands. All these complexes have been well characterized using single-crystal X-ray diffraction analyses, spectroscopic and magnetic investigations. Magneto-structural studies showed that 1 and 2 adopt a mononuclear structure with CoN4O2 octahedral coordination geometry while 3 and 4 have a 2D [4 x 4] rhombic grid coordination networks (CNs) where each cobalt(II) center is in a CoN6 octahedral coordination environment. Static magnetic measurements reveal that all four complexes displayed a high spin (HS) (S = 3/2) state between 2 and 280 K which was further confirmed by X-band and Q-band EPR studies. Remarkably, along with the molecular dimensionality (0D and 2D) the modification in the axial coligands lead to a significant difference in the dynamic magnetic properties of the monomers and CNs at low temperatures. All complexes display slow magnetic relaxation behavior under an external dc magnetic field. For the complexes with NCS- as coligand observed higher energy barrier for spin reversal in comparison to the complexes with NCSe- as coligand, while mononuclear complex 1 exhibited a higher energy barrier than that of CN 3. Theoretical calculations at the DFT and CASSCF level of theory have been performed to get more insight into the electronic structure and magnetic properties of all four complexes.
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Affiliation(s)
- Subrata Ghosh
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Sir C. V. Raman Road, 560012, Bangalore, India
| | - Sujit Kamilya
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Sir C. V. Raman Road, 560012, Bangalore, India
| | - Sakshi Mehta
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Sir C. V. Raman Road, 560012, Bangalore, India
| | - Radovan Herchel
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, CZ-771 46, Olomouc, Czech Republic
| | - Mikhail Kiskin
- N. S. Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Leninsky Prosp. 31, 119991, Moscow, Russia
| | - Sergey Veber
- International Tomography Center of the Siberian Branch of the Russian Academy of Sciences, Institutskaya Str. 3a, 630090, Novosibirsk, Russia
- Novosibirsk State University, Pirogova Str. 1, 630090, Novosibirsk, Russia
| | - Matvey Fedin
- International Tomography Center of the Siberian Branch of the Russian Academy of Sciences, Institutskaya Str. 3a, 630090, Novosibirsk, Russia
- Novosibirsk State University, Pirogova Str. 1, 630090, Novosibirsk, Russia
| | - Abhishake Mondal
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Sir C. V. Raman Road, 560012, Bangalore, India
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63
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Juráková J, Šalitroš I. Co(II) single-ion magnets: synthesis, structure, and magnetic properties. MONATSHEFTE FUR CHEMIE 2022; 153:1001-1036. [PMID: 35615113 PMCID: PMC9123880 DOI: 10.1007/s00706-022-02920-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 04/25/2022] [Indexed: 01/01/2023]
Abstract
Magnetoactive coordination compounds exhibiting bi- or multistability between two or more magnetic stable states present an attractive example of molecular switches. Currently, the research is focused on molecular nanomagnets, especially single molecule magnets (SMMs), which are molecules, where the slow relaxation of the magnetization based on the purely molecular origin is observed. Contrary to ferromagnets, the magnetic bistability of SMMs does not require intermolecular interactions, which makes them particularly interesting in terms of application potential, especially in the high-density storage of data. This paper aims to introduce the readers into a basic understanding of SMM behaviour, and furthermore, it provides an overview of the attractive Co(II) SMMs with emphasis on the relation between structural features, magnetic anisotropy, and slow relaxation of magnetization in tetra-, penta-, and hexacoordinate complexes.
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Affiliation(s)
- Jana Juráková
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 61200 Brno, Czech Republic
| | - Ivan Šalitroš
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 61200 Brno, Czech Republic
- Department of Inorganic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Bratislava, 81237 Slovakia
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 771 46, Olomouc, Czech Republic
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64
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Nain S, Khurana R, Ali ME. Harnessing Colossal Magnetic Anisotropy in Sandwiched 3d 2-Metallocenes. J Phys Chem A 2022; 126:2811-2817. [PMID: 35507013 DOI: 10.1021/acs.jpca.2c01605] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Single-molecule magnets are gaining attention in recent years with the growing focus on achieving higher barriers of magnetization reversal. Metallocenes, owing to their unique sandwiched structure, assure themselves as plausible molecular systems for the development of novel single-molecule magnets (SMMs). Here in this work, we have explicitly investigated metallocenes of first-row transition elements, along with their one-electron-oxidized (cationic) and -reduced (anionic) analogues, for their magnetic anisotropies by adopting multireference ab initio calculations. Herein, we report a high magnetic anisotropy for 3d2 systems among all 3d-metallocenes.
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Affiliation(s)
- Sakshi Nain
- Institute of Nano Science and Technology, Sector-81, Mohali 140306, Punjab, India
| | - Rishu Khurana
- Institute of Nano Science and Technology, Sector-81, Mohali 140306, Punjab, India
| | - Md Ehesan Ali
- Institute of Nano Science and Technology, Sector-81, Mohali 140306, Punjab, India
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65
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Comba P, Rajaraman G, Sarkar A, Velmurugan G. What controls the magnetic anisotropy in heptacoordinate high-spin cobalt(II) complexes? A theoretical perspective. Dalton Trans 2022; 51:5175-5183. [PMID: 35274660 DOI: 10.1039/d1dt03903b] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The magnetic anisotropy of sixteen seven-coordinate high-spin CoII complexes with O, N, Cl and I donors was investigated with state-of-the-art ab initio CASSCF/NEVPT2 calculations and compared with experimental data. Based on the nature of the equatorial and axial ligands, which were found to tune the zero-field splitting, the complexes were classified into four groups. The experimental zero-field splitting parameters D which, for the various structures are in a range of +30 to +60 cm-1, as well as the g and E values are well reproduced. The investigation of the electronic structure shows that in these pentagonal bipyramidal complexes the donors and symmetry in the equatorial plane play an important role in the values of the axial zero-field splitting parameter D, and breaking of the horizontal plane of symmetry was found to enhance the magnitude of the D value. Although negative values of D are a desired condition for SIMs, many CoII based SIMs with positive zero-field splitting are fundamentally important to understand the nature of magnetic anisotropy, and seven coordinate CoII complexes with a large overall crystal field splitting might provide a way forward in this class of molecules.
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Affiliation(s)
- Peter Comba
- Heidelberg University, Institute of Inorganic Chemistry and Interdisciplinary Center for Scientific Computing, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.
| | - Arup Sarkar
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.
| | - Gunasekaran Velmurugan
- Heidelberg University, Institute of Inorganic Chemistry and Interdisciplinary Center for Scientific Computing, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
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66
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Yin ZB, Wei J, Xi Z. Trisyl-based multidentate ligands: synthesis and their transition-metal complexes. Dalton Trans 2022; 51:3431-3438. [PMID: 35179149 DOI: 10.1039/d2dt00049k] [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
Herein we report the synthesis and applications of unusual trisyl-based multidentate ligands [trisyl = tris(trimethylsilyl)methyl, -C(SiMe3)3]. First, by applying a new trisyl synthon (Me3Si)2CH(SiMe2CH2Cl) 1, trisyl-based S- or N-containing compounds 2 were efficiently obtained. On treatment of these compounds 2 with MeLi, their corresponding S- or N-coordinated pincer-like trisyl-based lithium salts 3, including the S-bridged ditrisyl compound 3a [Li{C(SiMe3)2SiMe2CH2SCH2SiMe2C(SiMe3)2}Li(DME)3] and the N-coordinated monotrisyl compounds 3b [(NacNacDippLiCH2SiMe2C(SiMe3)2Li(THF)], 3c [Li(THF){C(SiMe3)2SiMe2CH2N(Me)CH2C5H4N-2}], and 3d [Li{C(SiMe3)2SiMe2CH2N(Me)CH2CH2N(iPr)2}] were synthesized and structurally characterized by single-crystal X-ray structural analysis. Second, to test these novel lithium salts as straightforward precursors for the synthesis of transition-metal complexes with unique structures, these lithium salts were applied to react with MCl2 (M = Cr, Mn, Fe, Co). Their corresponding transition-metal complexes 4-8 were obtained in high yields and structurally characterized by single-crystal X-ray structural analysis. Third, the preliminary reactivities of compound 4 were explored.
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Affiliation(s)
- Zhu-Bao Yin
- Beijing National Laboratory for Molecular Sciences, MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry, Peking University, Beijing 100871, China.
| | - Junnian Wei
- Beijing National Laboratory for Molecular Sciences, MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry, Peking University, Beijing 100871, China.
| | - Zhenfeng Xi
- Beijing National Laboratory for Molecular Sciences, MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry, Peking University, Beijing 100871, China.
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67
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Slow-Relaxation Behavior of a Mononuclear Co(II) Complex Featuring Long Axial Co-O Bond. NANOMATERIALS 2022; 12:nano12040707. [PMID: 35215035 PMCID: PMC8875892 DOI: 10.3390/nano12040707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 02/13/2022] [Accepted: 02/18/2022] [Indexed: 02/01/2023]
Abstract
Co(II) mononuclear complex with different coordination geometry would display various of field-induced single-ion magnet (SIM) behaviors. Here, we identify a field-induced single-ion magnet in a mononuclear complex Co(H2DPA)2·H2O (H2DPA = 2,6-pyridine-dicarboxylic acid) by the hydrothermal method. The long axial Co-O coordination bond (Co1‧‧‧O3) can be formed by Co1 and O3. Therefore, Co(II) ion is six-coordinated in a distorted elongated octahedron. AC magnetization susceptibilities show that the effective energy barrier is up to 43.28 K. This is much larger than most mononuclear Co(II). The distorted elongated octahedron caused by the axial Co-O coordination bond is responsible for the high effective energy barrier. The distribution of electron density in Co1 and O3 atoms in the long axial bond would influence the magnetic relaxation process in turn. Our work deepens the relationship between the effective energy barrier and the weak change of ligand field by long axial bonds, which would facilitate constructing SIM with high energy temperature.
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68
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Kragskow JGC, Marbey J, Buch CD, Nehrkorn J, Ozerov M, Piligkos S, Hill S, Chilton NF. Analysis of vibronic coupling in a 4f molecular magnet with FIRMS. Nat Commun 2022; 13:825. [PMID: 35149674 PMCID: PMC8837795 DOI: 10.1038/s41467-022-28352-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 01/19/2022] [Indexed: 11/09/2022] Open
Abstract
Vibronic coupling, the interaction between molecular vibrations and electronic states, is a fundamental effect that profoundly affects chemical processes. In the case of molecular magnetic materials, vibronic, or spin-phonon, coupling leads to magnetic relaxation, which equates to loss of magnetic memory and loss of phase coherence in molecular magnets and qubits, respectively. The study of vibronic coupling is challenging, and most experimental evidence is indirect. Here we employ far-infrared magnetospectroscopy to directly probe vibronic transitions in [Yb(trensal)] (where H3trensal = 2,2,2-tris(salicylideneimino)trimethylamine). We find intense signals near electronic states, which we show arise due to an "envelope effect" in the vibronic coupling Hamiltonian, which we calculate fully ab initio to simulate the spectra. We subsequently show that vibronic coupling is strongest for vibrational modes that simultaneously distort the first coordination sphere and break the C3 symmetry of the molecule. With this knowledge, vibrational modes could be identified and engineered to shift their energy towards or away from particular electronic states to alter their impact. Hence, these findings provide new insights towards developing general guidelines for the control of vibronic coupling in molecules.
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Affiliation(s)
- Jon G C Kragskow
- Department of Chemistry, School of Natural Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Jonathan Marbey
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA.,Department of Physics, Florida State University, Tallahassee, FL, 32306, USA
| | - Christian D Buch
- Department of Chemistry, University of Copenhagen, DK-2100, Copenhagen, Denmark
| | - Joscha Nehrkorn
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA
| | - Mykhaylo Ozerov
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA
| | - Stergios Piligkos
- Department of Chemistry, University of Copenhagen, DK-2100, Copenhagen, Denmark.
| | - Stephen Hill
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA. .,Department of Physics, Florida State University, Tallahassee, FL, 32306, USA.
| | - Nicholas F Chilton
- Department of Chemistry, School of Natural Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
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69
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Trigonally Distorted Hexacoordinate Co(II) Single-Ion Magnets. MATERIALS 2022; 15:ma15031064. [PMID: 35161010 PMCID: PMC8839918 DOI: 10.3390/ma15031064] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 01/21/2022] [Accepted: 01/26/2022] [Indexed: 02/01/2023]
Abstract
By simple reactions involving various cobalt(II) carboxylates (acetate and in situ prepared pivalate and 4-hydroxybenzoate salts) and neocuproine (neo), we were able to prepare three different carboxylate complexes with the general formula [Co(neo)(RCOO)2] (R = –CH3 for 1, (CH3)3C– for 2, and 4OH-C4H6– for 3). The [Co(neo)(RCOO)2] molecules in the crystal structures of 1–3 adopt a rather distorted coordination environment, with the largest trigonal distortion observed for 1, whereas 2 and 3 are similarly distorted from ideal octahedral geometry. The combined theoretical and experimental investigations of magnetic properties revealed that the spin Hamiltonian formalism was not a valid approach and the L-S Hamiltonian had to be used to reveal very large magnetic anisotropies for 1–3. The measurements of AC susceptibility showed that all three compounds exhibited slow-relaxation of magnetization in a weak external static magnetic field, and thus can be classified as field-induced single-ion magnets. It is noteworthy that 1 also exhibits a weak AC signal in a zero-external magnetic field.
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70
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Harper DR, Nandy A, Arunachalam N, Duan C, Janet JP, Kulik HJ. Representations and strategies for transferable machine learning Improve model performance in chemical discovery. J Chem Phys 2022; 156:074101. [DOI: 10.1063/5.0082964] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Daniel R Harper
- Massachusetts Institute of Technology, United States of America
| | - Aditya Nandy
- Massachusetts Institute of Technology, United States of America
| | | | - Chenru Duan
- Massachusetts Institute of Technology, United States of America
| | | | - Heather J. Kulik
- Dept of Chemical Engineering, Massachusetts Institute of Technology, United States of America
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71
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Yambulatov DS, Nikolaevskii SA, Babeshkin KA, Efimov NN, Kiskin MA, Eremenko IL. Synthesis, structure, and magnetic properties of the cobalt(ii) iodide complex with 1,4-diazabuta-1,3-diene ligand. Russ Chem Bull 2022. [DOI: 10.1007/s11172-021-3358-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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72
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Blackaby WJM, Harriman KLM, Greer SM, Folli A, Hill S, Krewald V, Mahon MF, Murphy DM, Murugesu M, Richards E, Suturina E, Whittlesey MK. Extreme g-Tensor Anisotropy and Its Insensitivity to Structural Distortions in a Family of Linear Two-Coordinate Ni(I) Bis-N-heterocyclic Carbene Complexes. Inorg Chem 2022; 61:1308-1315. [PMID: 35005902 DOI: 10.1021/acs.inorgchem.1c02413] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report a new series of homoleptic Ni(I) bis-N-heterocyclic carbene complexes with a range of torsion angles between the two ligands from 68° to 90°. Electron paramagnetic resonance measurements revealed a strongly anisotropic g-tensor in all complexes with a small variation in g∥ ∼ 5.7-5.9 and g⊥ ∼ 0.6. The energy of the first excited state identified by variable-field far-infrared magnetic spectroscopy and SOC-CASSCF/NEVPT2 calculations is in the range 270-650 cm-1. Magnetic relaxation measured by alternating current susceptibility up to 10 K is dominated by Raman and direct processes. Ab initio ligand-field analysis reveals that a torsion angle of <90° causes the splitting between doubly occupied dxz and dyz orbitals, which has little effect on the magnetic properties, while the temperature dependence of the magnetic relaxation appears to have no correlation with the torsion angle.
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Affiliation(s)
| | - Katie L M Harriman
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie, Ottawa, Ontario K1N 6N5, Canada
| | - Samuel M Greer
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States.,Department of Chemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Andrea Folli
- School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, 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
| | - Vera Krewald
- Theoretical Chemistry, TU Darmstadt, Alarich-Weiss-Strasse 4, 64287 Darmstadt, Germany
| | - Mary F Mahon
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, U.K
| | - Damien M Murphy
- School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, U.K
| | - Muralee Murugesu
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie, Ottawa, Ontario K1N 6N5, Canada
| | - Emma Richards
- School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, U.K
| | - Elizaveta Suturina
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, U.K
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73
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Shao D, Moorthy S, Zhou Y, Wu ST, Zhu JY, Yang J, Wu D, Tian Z, Singh SKK. Field-induced slow magnetic relaxation behaviours in binuclear cobalt(II) metallocycle and exchange-coupled cluster. Dalton Trans 2022; 51:9357-9368. [DOI: 10.1039/d2dt01620f] [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
Precise control of structures and magnetic properties of a molecular material constitutes an important challenge to realize the tailor-made magnetic function. Herein, we reported that the ligand-directed coordination self-assembly of...
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74
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Zhu Z, Tang J. Metal–metal bond in lanthanide single-molecule magnets. Chem Soc Rev 2022; 51:9469-9481. [DOI: 10.1039/d2cs00516f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This review surveys recent critical advances in lanthanide SMMs, highlighting the influences of metal–metal bonds on the magnetization dynamics.
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Affiliation(s)
- 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
| | - Jinkui Tang
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
- School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, P. R. China
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75
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Qu YX, Ruan ZY, Lyu BH, Chen YC, Huang GZ, Liu JL, Tong ML. Opening Magnetic Hysteresis via Improving Planarity of Equatorial Coordination by Hydrogen Bonding. Dalton Trans 2022; 51:7986-7996. [DOI: 10.1039/d2dt01107g] [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
Through a mixed-ligand strategy, the structural change from a discrete dinuclear DyIII cluster to a one-dimensional polymeric chain was achieved, maintaining the two magnetic entities with the same {Dy(dppbO2)2(H2O)5} (dppbO2...
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76
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Otlyotov A, Moshchenkov A, Cavallo L, Minenkov Y. 16OSTM10: A new open-shell transition metal conformational energies database to challenge contemporary semiempirical and force field methods. Phys Chem Chem Phys 2022; 24:17314-17322. [DOI: 10.1039/d2cp01659a] [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
transition metal (OSTM) complexes has been developed. Contemporary composite density functional theory (DFT) (PBEh-3c, B97-3c), semiempirical (PM6, PM7) and the methods of GFNn-xTB/FF family were examined against conventional DFT (PBE-D3(BJ),...
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77
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Tao Y, Wang LN, Li HY, Qin XH, Yao D, Huang FP. Crystal structure, assembly process, and single-molecule magnet behavior of a triangular prismatic {Co 9} cluster. Dalton Trans 2022; 51:16653-16658. [DOI: 10.1039/d2dt02468c] [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
The crystal structure, assembly process and magnetic properties of a triangular prismatic [Co9(btdpa)3(CH2OCH2OH)6]·3.5H2O were reported: the cluster exhibits slow magnetization relaxation of single molecule magnets at zero field.
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Affiliation(s)
- Ye Tao
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin 541004, P. R. China
| | - Lu-Na Wang
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin 541004, P. R. China
| | - Hai-Ye Li
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin 541004, P. R. China
| | - Xiao-Huan Qin
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin 541004, P. R. China
| | - Di Yao
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin 541004, P. R. China
| | - Fu-Ping Huang
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin 541004, P. R. China
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78
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Li Y, Xi J, Ferrando-Soria J, Zhang YQ, Wang W, Song Y, Guo Y, Pardo E, Liu X. Slow magnetic relaxation in a trigonal-planar mononuclear Fe(II) complex. Dalton Trans 2022; 51:8266-8272. [DOI: 10.1039/d2dt00899h] [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
Based on a β-diketiminate ligand, an iron(III) tetrahedral high-spin complex, [LFeIII(Cl)2] (1), and an iron(II) high-spin triangular planar complex, [LFeIICl] (2), have been synthesized and structurally characterized. Also, complex 1...
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79
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Ding MM, Shang T, Hu R, Zhang YQ. Understanding the Magnetic Anisotropy for Linear Sandwich [Er(COT)]+-based Compounds: A Theoretical Investigation. Dalton Trans 2022; 51:3295-3303. [DOI: 10.1039/d1dt04157f] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of linear sandwich single-ion magnets containing [Er(COT)]+ fragment were selected to probe the magneto-structural correlations using ab initio methods. For prolate shaped ErIII ion, an equatorially coordinating geometry...
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80
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Tian Z, Moorthy S, Xiang H, Peng P, You M, Zhang Q, Yang SY, Zhang YL, Wu D, Singh SKK, Shao D. Tuning chain topologies and magnetic anisotropy in one-dimensional cobalt(II) coordination polymers via distinct dicarboxylates. CrystEngComm 2022. [DOI: 10.1039/d2ce00437b] [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
Based on a terpyridine derivative and two different dicarboxylate ligands, two new cobalt(II) coordination polymers, namely [Co(pytpy)(DClbdc)]n (1) and [Co(pytpy)(ndc)]n (2) (pytpy = 4'-(4-Pyridyl)-2,2':6',2''-terpyridine, H2DClbc = 2,5-Dichloroterephthalic acid, and H2ndc...
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81
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Charytanowicz T, Jankowski R, Zychowicz M, Chorazy S, Sieklucka B. The rationalized pathway from field-induced slow magnetic relaxation in CoII–WIV chains to single-chain magnetism in isotopological CoII–WV analogues. Inorg Chem Front 2022. [DOI: 10.1039/d1qi01427g] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The change of the oxidation state from WIV to WV in isotopological CoII–[W(CN)8]n− chains leads to the appearence of pronounced single-chain magnet behaviour.
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Affiliation(s)
- Tomasz Charytanowicz
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
| | - Robert Jankowski
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
| | - Mikolaj Zychowicz
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
| | - Szymon Chorazy
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
| | - Barbara Sieklucka
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
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82
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Luo QC, Ge N, Zhai YQ, Wang T, Sun L, Sun Q, Li F, Ouyang Z, Wang Z, Zheng YZ. A C,S Bonded Quasi-Two-Coordinate Chromium(II) Complex Showing Field-induced Slow Magnetic Relaxation Behaviour. Dalton Trans 2022; 51:9218-9222. [DOI: 10.1039/d2dt01131j] [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
A C,S bonded quasi-two-coordinate Cr(II) complex, Cr(SAr*)2 (HSAr* = HSC6H3-2,6(C6H2-2,4,6-Pri3)2), has been successfully synthesized. Magnetic, high-frequency / field electron paramagnetic resonance (HF-EPR) experiments and ab initio calculation studies show that...
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83
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Zhou Y, Li Y, Xi J, Qin Y, Cen P, Zhang YQ, Guo Y, Ding Y, Liu X. Modulation of the architectures and magnetic dynamics in pseudotetrahedral cobalt(II) complexes. Dalton Trans 2022; 51:7673-7680. [DOI: 10.1039/d2dt01047j] [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
Two β-Diketiminate cobalt(II) compounds of formula [LCo(μ-Cl)]2∙2C6H14 (1) and [LCoClPy]∙0.5C7H8∙0.5C6H14 (2) (L = [PhC-(PhCN-Dip)2]−, Dip = 2,6-iPr2C6H3) have been synthesized and structurally characterized by single crystal X-ray diffraction. Compound 1...
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84
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Chen YC, Tong ML. Single-Molecule Magnets beyond a Single Lanthanide Ion: The Art of Coupling. Chem Sci 2022; 13:8716-8726. [PMID: 35975153 PMCID: PMC9350631 DOI: 10.1039/d2sc01532c] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 06/23/2022] [Indexed: 11/22/2022] Open
Abstract
The promising future of storing and processing quantized information at the molecular level has been attracting the study of Single-Molecule Magnets (SMMs) for almost three decades. Although some recent breakthroughs are mainly about the SMMs containing only one lanthanide ion, we believe SMMs can tell a much deeper story than the single-ion anisotropy. Here in this Perspective, we will try to draw a unified picture of SMMs as a delicately coupled spin system between multiple spin centres. The hierarchical couplings will be presented step-by-step, from the intra-atomic hyperfine coupling, to the direct and indirect intra-molecular couplings with neighbouring spin centres, and all the way to the inter-molecular and spin–phonon couplings. Along with the discussions on their distinctive impacts on the energy level structures and thus magnetic behaviours, a promising big picture for further studies is proposed, encouraging the multifaceted developments of molecular magnetism and beyond. In this Perspective, we draw a unified picture for single-molecule magnets as delicately coupled spin systems, discuss the hierarchical couplings (from intra-atomic to inter-molecular) and their distinctive impacts on the magnetic behaviours.![]()
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Affiliation(s)
- Yan-Cong Chen
- Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry, Sun Yat-Sen University Guangzhou 510006 P. R. China
| | - Ming-Liang Tong
- Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry, Sun Yat-Sen University Guangzhou 510006 P. R. China
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85
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Landart Gereka A, Quesada-Moreno MM, Díaz-Ortega IF, Nojiri H, Ozerov M, Krzystek J, Palacios MA, Colacio E. Large easy-axis magnetic anisotropy in a series of trigonal prismatic mononuclear cobalt (II) complexes with zero-field hidden single-molecule magnet behaviour: The important role of the distortion of the coordination sphere and intermolecular interactions on the slow relaxation. Inorg Chem Front 2022. [DOI: 10.1039/d2qi00275b] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The complexes [Co(L)]X·S (X = CoCl42- , S = CH3CN (1); X = ZnCl42- , S = CH3OH (2)), [Co(L)]X2·S (X = ClO4-, S = 2CH3OH (3) and X =...
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86
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Deeth RJ. Ligand Field Theory for Linear ML
2
Complexes. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Robert J. Deeth
- Department of Chemistry University of Warwick CV4 7AL Coventry UK
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87
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Yao B, Singh MK, Deng YF, Zhang YZ. A Dicobalt(II) Single-Molecule Magnet via a Well-Designed Dual-Capping Tetrazine Radical Ligand. Inorg Chem 2021; 60:18698-18705. [PMID: 34823356 DOI: 10.1021/acs.inorgchem.1c02094] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The recent years have witnessed the glory development for the construction of high-performance mononuclear single molecule magnets (SMMs) within a specific coordination geometry, which, however, is not well applied in cluster-based SMMs due to the synthetic challenges. Given that the monocobalt(II) complexes within a trigonal-prismatic (TPR) coordination geometry have been classified as excellent SMMs with huge axial anisotropy (D ≈ -100 cm-1), here we designed and synthesized a new dual-capping tetrazine ligand, 3,6-bis(6-(di(1H-pyrazol-1-yl)methyl)pyridin-2-yl)-1,2,4,5-tetrazine (bpptz), and prepared a novel dicobalt(II) complex, [Cp2CoIII][{(hfac)CoII}2(bpptz•-)][hfac]2·2Et2O (1, hfac = hexafluoroacetylacetonate). In the structure of 1, the bpptz•- radical ligand enwraps two Co(II) centers within quasi-TPR geometries, which are further bridged by the tetrazine radical in the trans mode. The magnetic study revealed that the interaction between the Co centers and the tetrazine radical is strongly antiferromagnetic with a coupling constant (J) of -65.8 cm-1 (in the -2J formalism). Remarkably, 1 exhibited the typical SMM behavior with an effective energy barrier of 69 cm-1 under a 1.5 kOe dc field, among the largest for polynuclear transition metal SMMs. In addition, DFT and ab initio calculations suggested that the presence of a strong Co(II)-radical magnetic interaction effectively quenches the QTM effect and enhances the barrier height for the magnetization reversal.
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Affiliation(s)
- Binling Yao
- Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
| | - Mukesh Kumar Singh
- EastCHEM School of Chemistry, The University of Edinburgh, David Brewster Road, Edinburgh, Scotland EH9 3FJ, U.K
| | - Yi-Fei Deng
- Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
| | - Yuan-Zhu Zhang
- Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
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88
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Lu F, Guo WX, Zhang YQ. Largely Enhancing the Blocking Energy Barrier and Temperature of a Linear Cobalt(II) Complex through the Structural Distortion: A Theoretical Exploration. Inorg Chem 2021; 61:295-301. [PMID: 34923824 DOI: 10.1021/acs.inorgchem.1c02858] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Complete-active-space self-consistent field and N-electron valence second-order perturbation theory have both been employed to investigate the magnetic anisotropy of one two-coordinate cobalt(II) compound via altering the Co-C bond lengths and twist angle φ. The calculated energy barrier Ueff decreases with the decrease in the Co-C bond lengths due to the gradually increasing interaction between the 3d orbitals of CoII and the coordination ligand field and then to the decrease in the ground orbital angular moment L of CoII. Thus, we cannot improve Ueff simply by shortening the Co-C bond lengths. However, by rotating the twist angle φ from 60 to 0°, it is surprising to find that the energy barrier and blocking temperature can be enhanced up to 1559.1 cm-1 and 90 K, respectively, with φ = 0°, which are prominent even among lanthanide-based single-molecule magnets.
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Affiliation(s)
- Fang Lu
- Jiangsu Key Lab for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing 210023, P. R. China
| | - Wen-Xiao Guo
- Jiangsu Key Lab for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing 210023, P. R. China
| | - Yi-Quan Zhang
- Jiangsu Key Lab for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing 210023, P. R. China
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89
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Amoza M, Maxwell L, Aliaga-Alcalde N, Gómez-Coca S, Ruiz E. Spin-Phonon Coupling and Slow-Magnetic Relaxation in Pristine Ferrocenium. Chemistry 2021; 27:16440-16447. [PMID: 34582589 PMCID: PMC9298439 DOI: 10.1002/chem.202102603] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Indexed: 01/23/2023]
Abstract
We report the spin dynamic properties of non‐substituted ferrocenium complexes. Ferrocenium shows a field‐induced single‐molecule magnet behaviour in DMF solution while cobaltocene lacks slow spin relaxation neither in powder nor in solution. Multireference quantum mechanical calculations give a non‐Aufbau orbital occupation for ferrocenium with small first excitation energy that agrees with the relatively large measured magnetic anisotropy for a transition metal S=1/2 system. The analysis of the spin relaxation shows an important participation of quantum tunnelling, Raman, direct and local‐mode mechanisms which depend on temperature and the external field conditions. The calculation of spin‐phonon coupling constants for the vibrational modes shows that the first vibrational mode, despite having a low spin‐phonon constant, is the most efficient process for the spin relaxation at low temperatures. In such conditions, vibrational modes with higher spin‐phonon coupling constants are not populated. Additionally, the vibrational energy of this first mode is in excellent agreement with the experimental fitted value obtained from the local‐mode mechanism.
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Affiliation(s)
- Martín Amoza
- Departament de Química Inorgànica i Orgànica and, Institut de Recerca de Química Teòrica i Computacional, Universitat de Barcelona, Diagonal 645, 08028, Barcelona, Spain
| | - Lindley Maxwell
- Departament de Química Inorgànica i Orgànica and, Institut de Recerca de Química Teòrica i Computacional, Universitat de Barcelona, Diagonal 645, 08028, Barcelona, Spain.,Advanced Lithium and Industrial Minerals Research Center, Universidad de Antofagasta, Av. Universidad de Antofagasta, 02800, Antofagasta, Chile
| | - Núria Aliaga-Alcalde
- ICREA, Institució Catalana de Recerca i Estudis Avançats, Passeig, Passeig Lluis Companys 23, 08010, Barcelona, Spain.,Institut de Ciència de Materials de Barcelona ICMAB-CSIC, Campus UAB, 08193, Bellaterra, Catalonia, Spain
| | - Silvia Gómez-Coca
- Departament de Química Inorgànica i Orgànica and, Institut de Recerca de Química Teòrica i Computacional, Universitat de Barcelona, Diagonal 645, 08028, Barcelona, Spain
| | - Eliseo Ruiz
- Departament de Química Inorgànica i Orgànica and, Institut de Recerca de Química Teòrica i Computacional, Universitat de Barcelona, Diagonal 645, 08028, Barcelona, Spain
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90
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Syntheses, Structures and Magnetic Properties of M2 (M = Fe, Co) Complexes with N6 Coordination Environment: Field-Induced Slow Magnetic Relaxation in Co2. MAGNETOCHEMISTRY 2021. [DOI: 10.3390/magnetochemistry7120153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Two dinuclear complexes [M2(H2L)2](ClO4)4·2MeCN (M = Co for Co2 and Fe for Fe2) were synthesized using a symmetric hydrazone ligand with the metal ions in an N6 coordination environment. The crystal structures and magnetic properties were determined by single-crystal X-ray diffraction and magnetic susceptibility measurements. The crystal structure study revealed that the spin centers were all in the high-spin state with a distorted octahedron (Oh) geometry. Dynamic magnetic properties measurements revealed that complex Co2 exhibited field-induced single-molecule magnet properties with two-step relaxation in which the fast relaxation path was from QTM and the slow relaxation path from the thermal relaxation under an applied field.
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91
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Briganti M, Totti F, Andruh M. Hetero-tri-spin systems: an alternative stairway to the single molecule magnet heaven? Dalton Trans 2021; 50:15961-15972. [PMID: 34647933 DOI: 10.1039/d1dt02511b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The search for molecule-based magnetic materials has stimulated over the years the development of extremely rich coordination chemistry. Various combinations of spin carriers have been investigated and illustrated by a plethora of hetero-spin complexes: 3d-nd, 3d-4f, 2p-3d, and 2p-4f. More recently, two other classes of hetero-spin complexes have grown rapidly: compounds containing three different paramagnetic metal ions, or one radical and two different paramagnetic metal ions (all within the same molecular entity). Such new classes of systems represent a challenge both from a synthetic and theoretical point of view. Indeed, the synthetic control and the understanding of the spin topology effect on the overall magnetic behavior from first-principles is a difficult problem to be solved. The presence of different spin carriers in a single molecule makes such compounds particularly interesting because they offer the possibility of developing new magnetic properties, different from those of hetero-bi-spin or homo-spin systems. A critical overview taking the case of 2p-3d-4f complexes is the focus of this perspective paper. An original organic picture of the state-of-art in this field and new hints about the main directions that should be pursued to achieve hetero-tri-spin systems with large anisotropy barriers, low quantum tunneling of magnetization and, possibly, large blocking temperatures are provided in this article through an analysis based on numerically revisiting already published data and a critical survey of the literature reported so far. The reasons for the limited success obtained for the largely used 3d-2p-4f topology are given along with the ones explaining the failure for the 2p-4f-3d case. The still never synthesized linear 2p-3d-4f spin topology seemed to be the most promising one based on the results obtained for the unique closed hetero-tri-spin closed triangular system synthesized so far.
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Affiliation(s)
- Matteo Briganti
- Department of Chemistry "U. Schiff" and INSTM UdR Firenze, University of Florence, Via della Lastruccia 3-13, 50019 Sesto Fiorentino, Italy.
| | - Federico Totti
- Department of Chemistry "U. Schiff" and INSTM UdR Firenze, University of Florence, Via della Lastruccia 3-13, 50019 Sesto Fiorentino, Italy.
| | - Marius Andruh
- Inorganic Chemistry Laboratory, Faculty of Chemistry, University of Bucharest, Str. Dumbrava Rosie nr. 23, 020464 Bucharest, Romania. .,"Costin D. Nenitzescu" Institute of Organic Chemistry of the Romanian Academy, Spl. Independentei nr. 202B, Bucharest, Romania
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92
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Jiménez JR, Xu B, El Said H, Li Y, von Bardeleben J, Chamoreau LM, Lescouëzec R, Shova S, Visinescu D, Alexandru MG, Cano J, Julve M. Field-induced single ion magnet behaviour of discrete and one-dimensional complexes containing [bis(1-methylimidazol-2-yl)ketone]-cobalt(II) building units. Dalton Trans 2021; 50:16353-16363. [PMID: 34734603 DOI: 10.1039/d1dt02441h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We describe herein the first examples of six-coordinate CoII single-ion magnets (SIMs) based on the β-diimine Mebik ligand [Mebik = bis(1-methylimidazol-2-yl)ketone]: two mononuclear [CoII(Rbik)2L2] complexes and one mixed-valence {CoIII2CoII}n chain of formulas [CoII(Mebik)(H2O)(dmso)(μ-NC)2CoIII2(μ-2,5-dpp)(CN)6]n·1.4nH2O (3) [L = NCS (1), NCSe (2) and 2,5-dpp = 2,5-bis(2-pyridyl)pyrazine (3)]. Two bidentate Mebik molecules plus two monodentate N-coordinated pseudohalide groups in cis positions build somewhat distorted octahedral surroundings around the high-spin cobalt(II) ions in 1 and 2. The diamagnetic [CoIII2(μ-2,5-dpp)(CN)8]2- metalloligand coordinates the paramagnetic [CoII(Mebik)(H2O)(dmso)]2+ complex cations in a bis-monodentate fashion to afford neutral zigzag heterobimetallic chains in 3. Ab initio calculations, and cryomagnetic dc (2.0-300 K) and ac (2.0-12 K) measurements as well as EPR spectroscopy for 1-3 show the existence of magnetically isolated high-spin cobalt(II) ions with D values of 59.84-89.90 (1), 66.32-93.90 (2) and 70.40-127.20 cm-1 (3) and field-induced slow relaxation of the magnetization, being thus new examples of SIMs with transversal magnetic anisotropy. The analysis of their relaxation dynamics reveals that the relaxation of the magnetization occurs by the Raman (with values of the n parameter covering the range 6.0-6.8) and direct spin-phonon processes.
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Affiliation(s)
- Juan-Ramón Jiménez
- Sorbonne Université, Institut Parisien de Chimie Moléculaire, UMR CNRS 8232, 4 place Jussieu, F-75252 Paris, France.
| | - Buqing Xu
- Sorbonne Université, Institut Parisien de Chimie Moléculaire, UMR CNRS 8232, 4 place Jussieu, F-75252 Paris, France.
| | - Hasnaa El Said
- Sorbonne Université, Institut Parisien de Chimie Moléculaire, UMR CNRS 8232, 4 place Jussieu, F-75252 Paris, France.
| | - Yanling Li
- Sorbonne Université, Institut Parisien de Chimie Moléculaire, UMR CNRS 8232, 4 place Jussieu, F-75252 Paris, France.
| | - Jurgen von Bardeleben
- Sorbonne Université, Institut des NanoSciences de Paris, UMR CNRS 7588, 4 place Jussieu, F-75252 Paris, France
| | - Lise-Marie Chamoreau
- Sorbonne Université, Institut Parisien de Chimie Moléculaire, UMR CNRS 8232, 4 place Jussieu, F-75252 Paris, France.
| | - Rodrigue Lescouëzec
- Sorbonne Université, Institut Parisien de Chimie Moléculaire, UMR CNRS 8232, 4 place Jussieu, F-75252 Paris, France.
| | - Sergiu Shova
- "Petru Poni" Institute of Macromolecular Chemistry, Romanian Academy, Aleea Grigore Ghica Vodă 41-A, RO-700487 Iasi, Romania
| | - Diana Visinescu
- Coordination and Supramolecular Chemistry Laboratory, "Ilie Murgulescu" Institute of Physical Chemistry, Romanian Academy, Splaiul Independentei 202, Bucharest 060021, Romania
| | - Maria-Gabriela Alexandru
- Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, 1-7 Gh. Polizu Street, 011061 Bucharest, Romania.
| | - Joan Cano
- Departament de Química Inorgànica/Instituto de Ciencia Molecular (ICMol), Universitat de València, C/Catedrático José Beltrán 2, 46990 Paterna, Valencia, Spain.
| | - Miguel Julve
- Departament de Química Inorgànica/Instituto de Ciencia Molecular (ICMol), Universitat de València, C/Catedrático José Beltrán 2, 46990 Paterna, Valencia, Spain.
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93
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Peng M, Wu XF, Wang LX, Chen SH, Xiang J, Jin XX, Yiu SM, Wang BW, Gao S, Lau TC. Slow magnetic relaxation in high-coordinate Co(II) and Fe(II) compounds bearing neutral tetradentate ligands. Dalton Trans 2021; 50:15327-15335. [PMID: 34636819 DOI: 10.1039/d1dt02575a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The first-row transition metal compounds, [MII(L1)2](ClO4)2 (M = Ni (1); Co (2)), have been prepared by treatment of a neutral tetradentate ligand (L1 = N2,N9-dibutyl-1,10-phenanthroline-2,9-dicarboxamide) with metal perchlorate salts in MeOH. Both compounds have been structurally characterized by X-ray crystallography and it was found that the coordination numbers are 6 and 7, respectively. The reaction of 6,6'-bis(2-tbutyl-tetrazol-5-yl)-2,2'-bipyridine (L2) with hydrated FeII(ClO4)2 afforded a 8-coordinate Fe(II) compound, [FeII(L2)2](ClO4)2 (3); however its reaction with hydrated CoII(ClO4)2 resulted in 6-coordinate [CoII(L2)2](ClO4)2. It is interesting to observe field-induced slow magnetic relaxation in the 7-coordinate Co(II) compound 2 and 8-coordinate Fe(II) compound 3, which further supports the validity of designing high coordination number compounds as single-molecule magnets. Direct current magnetic studies demonstrate that 2 has a very large positive D value (56.2 cm-1) and a small E value (0.66 cm-1), indicating easy plane magnetic anisotropy. Consistent with the larger D value, an effective spin-reversal barrier of Ueff = 100 K (71.4 cm-1) is obtained, which is the highest value reported for 7-coordinate Co(II) complexes with a pentagonal bipyramidal geometry. In contrast, 8-coordinate Fe(II) compound 3 exhibits uniaxial magnetic anisotropy.
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Affiliation(s)
- Min Peng
- College of Chemistry and Environmental Engineering, Yangtze University, Jingzhou 434020, HuBei, P. R. China.
| | - Xiao-Fan Wu
- State Key Laboratory of Rare Earth Materials Chemistry and Applications and PKU-HKU Joint Laboratory on Rare Earth Materials and Bioinorganic Chemistry, Peking University, Beijing 100871, P. R. China.
| | - Li-Xin Wang
- College of Chemistry and Environmental Engineering, Yangtze University, Jingzhou 434020, HuBei, P. R. China.
| | - Si-Huai Chen
- School of Chemistry and Environmental Engineering, Wuhan Institute of Technology, Wuhan 430073, P. R. China
| | - Jing Xiang
- College of Chemistry and Environmental Engineering, Yangtze University, Jingzhou 434020, HuBei, P. R. China.
| | - Xin-Xin Jin
- State Key Laboratory of Rare Earth Materials Chemistry and Applications and PKU-HKU Joint Laboratory on Rare Earth Materials and Bioinorganic Chemistry, Peking University, Beijing 100871, P. R. China.
| | - Shek-Man Yiu
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong, P. R. China.
| | - Bing-Wu Wang
- State Key Laboratory of Rare Earth Materials Chemistry and Applications and PKU-HKU Joint Laboratory on Rare Earth Materials and Bioinorganic Chemistry, Peking University, Beijing 100871, P. R. China.
| | - Song Gao
- State Key Laboratory of Rare Earth Materials Chemistry and Applications and PKU-HKU Joint Laboratory on Rare Earth Materials and Bioinorganic Chemistry, Peking University, Beijing 100871, P. R. China. .,South China University of Technology, P. R. China
| | - Tai-Chu Lau
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong, P. R. China.
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94
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Novikov VV, Nelyubina YV. Modern physical methods for the molecular design of single-molecule magnets. RUSSIAN CHEMICAL REVIEWS 2021. [DOI: 10.1070/rcr5002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Abstract
Many paramagnetic metal complexes have emerged as unique magnetic materials (single-molecule magnets), which behave as conventional magnets at the single-molecule level, thereby making it possible to use them in modern devices for data storage and processing. The rational design of these complexes, however, requires a deep understanding of the physical laws behind a single-molecule magnet behaviour, the mechanisms of magnetic relaxation that determines the magnetic properties and the relationship of these properties with the structure of single-molecule magnets. This review focuses on the physical methods providing such understanding, including different versions and various combinations of magnetometry, electron paramagnetic and nuclear magnetic resonance spectroscopy, optical spectroscopy and X-ray diffraction. Many of these methods are traditionally used to determine the composition and structure of new chemical compounds. However, they are rarely applied to study molecular magnetism.
The bibliography includes 224 references.
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95
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Gorbachev EA, Kozlyakova ES, Trusov LA, Sleptsova AE, Zykin MA, Kazin PE. Design of modern magnetic materials with giant coercivity. RUSSIAN CHEMICAL REVIEWS 2021. [DOI: 10.1070/rcr4989] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Abstract
The review is devoted to compounds and materials demonstrating extremely high magnetic hardness. The recent advances in the synthesis of modern materials for permanent magnets are considered, and a range of exotic compounds interesting for fundamental research is described. The key details of chemical composition, crystal structure and magnetic microstructure responsible for the appearance of high magnetic anisotropy and giant coercivity are analyzed. The challenges of developing the title materials are noted and strategies for their solution are discussed.
The bibliography includes 389 references.
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96
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Mondal A, Konar S. A remarkable energy barrier for spin reversal in a field induced dinuclear ytterbium single molecule magnet. Dalton Trans 2021; 50:13666-13670. [PMID: 34586116 DOI: 10.1039/d1dt02130c] [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
A dinuclear ytterbium complex has been designed with a strong ligand field in equatorial positions. Magnetic studies reveal the presence of easy-axis anisotropy and field induced slow relaxation of magnetization with a remarkable energy barrier, Ueff = 53.58 cm-1, the highest value reported for any Yb-based SMMs to date. Furthermore, the ab initio calculations disclose the importance of a weak axial ligand field to design high-performance Yb-based SMMs.
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Affiliation(s)
- Arpan Mondal
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal (IISERB), Bhopal By-pass Road, Bhauri, Bhopal-462066, India.
| | - Sanjit Konar
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal (IISERB), Bhopal By-pass Road, Bhauri, Bhopal-462066, India.
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97
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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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98
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Robert J, Turek P, Bailleul M, Boudalis AK. Broadband electron paramagnetic resonance of a molecular spin triangle. Phys Chem Chem Phys 2021; 23:20268-20274. [PMID: 34486006 DOI: 10.1039/d1cp03295j] [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 built a broadband Electron Paramagnetic Resonance (EPR) spectrometer capable of field- and frequency sweep experiments under field-, microwave amplitude- and microwave frequency-modulation detection modes (HM, AM, and FM, respectively). The spectrometer is based on a coplanar waveguide (CPW) architecture, with the sample being deposited on top of the transmission line. We tested the functionality of this spectrometer by measuring a standard 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl (DPPH) sample, and complex (NnBu4)2[Cu3(μ3-Cl)2(μ-pz)3Cl3] (1), drop-casted on the CPW. Complex 1 had been previously studied by conventional X-band EPR spectroscopy (Chem. - Eur. J., 2020, 26, 12769-1784), and comparison with the past studies validated the functionality of the spectrometer and confirmed the stability of the sample upon deposition. Moreover, our results highlighted the importance of surface effects and of the orientation of the microwave magnetic component B1 on the lineshapes of the recorded spectra.
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Affiliation(s)
- Jérôme Robert
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), UMR 7504, F-67000 Strasbourg, France
| | - Philippe Turek
- Institut de Chimie de Strasbourg (UMR 7177, CNRS-Unistra), Université de Strasbourg, 4 rue Blaise Pascal, CS 90032, F-67081 Strasbourg, France
| | - Matthieu Bailleul
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), UMR 7504, F-67000 Strasbourg, France
| | - Athanassios K Boudalis
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), UMR 7504, F-67000 Strasbourg, France.,Institut de Chimie de Strasbourg (UMR 7177, CNRS-Unistra), Université de Strasbourg, 4 rue Blaise Pascal, CS 90032, F-67081 Strasbourg, France.,Institut de Science et d'Ingénierie Suparamolaiculaires - ISIS, 8 allée Gaspard Monge, BP 70028, F-67083 Strasbourg Cedex, France.
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99
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Klahn EA, Damgaard-Møller E, Krause L, Kibalin I, Gukasov A, Tripathi S, Swain A, Shanmugam M, Overgaard J. Quantifying magnetic anisotropy using X-ray and neutron diffraction. IUCRJ 2021; 8:833-841. [PMID: 34584744 PMCID: PMC8420765 DOI: 10.1107/s2052252521008290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 08/11/2021] [Indexed: 06/13/2023]
Abstract
In this work, the magnetic anisotropy in two iso-structural distorted tetrahedral Co(II) complexes, CoX 2tmtu2 [X = Cl(1) and Br(2), tmtu = tetra-methyl-thio-urea] is investigated, using a combination of polarized neutron diffraction (PND), very low-temperature high-resolution synchrotron X-ray diffraction and CASSCF/NEVPT2 ab initio calculations. Here, it was found consistently among all methods that the compounds have an easy axis of magnetization pointing nearly along the bis-ector of the compression angle, with minute deviations between PND and theory. Importantly, this work represents the first derivation of the atomic susceptibility tensor based on powder PND for a single-molecule magnet and the comparison thereof with ab initio calculations and high-resolution X-ray diffraction. Theoretical ab initio ligand field theory (AILFT) analysis finds the d xy orbital to be stabilized relative to the d xz and d yz orbitals, thus providing the intuitive explanation for the presence of a negative zero-field splitting parameter, D, from coupling and thus mixing of d xy and . Experimental d-orbital populations support this interpretation, showing in addition that the metal-ligand covalency is larger for Br-ligated 2 than for Cl-ligated 1.
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Affiliation(s)
- Emil Andreasen Klahn
- Department of Chemistry, Aarhus University, Langelandsgade 140, Aarhus C 8000, Denmark
| | - Emil Damgaard-Møller
- Department of Chemistry, Aarhus University, Langelandsgade 140, Aarhus C 8000, Denmark
| | - Lennard Krause
- Department of Chemistry, Aarhus University, Langelandsgade 140, Aarhus C 8000, Denmark
| | - Iurii Kibalin
- LLB, CEA, CE de Saclay, Gif sur Yvette 91191, France
| | - Arsen Gukasov
- LLB, CEA, CE de Saclay, Gif sur Yvette 91191, France
| | - Shalini Tripathi
- Department of Chemistry, IIT Bombay, Powai, Mumbai, Maharashtra 400076, India
| | - Abinash Swain
- Department of Chemistry, IIT Bombay, Powai, Mumbai, Maharashtra 400076, India
| | | | - Jacob Overgaard
- Department of Chemistry, Aarhus University, Langelandsgade 140, Aarhus C 8000, Denmark
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100
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Yambulatov DS, Nikolaevskii SA, Shmelev MA, Babeshkin KA, Korchagin DV, Efimov NN, Goloveshkin AS, Petrov PA, Kiskin MA, Sokolov MN, Eremenko IL. Heterometallic Coii-Lii carboxylate complexes with N-heterocyclic carbene, triphenylphosphine and pyridine: a comparative study of magnetic properties. MENDELEEV COMMUNICATIONS 2021. [DOI: 10.1016/j.mencom.2021.09.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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