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Imperato M, Nicolini A, Ribas-Ariño J, Antkowiak M, Roubeau O, Cornia A, Novikov V, Barrios LA, Aromí G. Guest selectivity of [Ni 2] supramolecular helicates. Dalton Trans 2024; 53:12301-12306. [PMID: 38984518 DOI: 10.1039/d4dt01611d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2024]
Abstract
Two new paramagnetic supramolecular helicates with the formula (X@[Ni2L3])3+ (X = Cl, or Br; L = a bis-pyrazolylpyridine ligand) have been prepared and are described. Helicates of this metal are very rare with virtually no prior examples of them acting as hosts of anionic species. The persistence of the new assemblies in solution has been demonstrated unambiguously by mass spectrometry and paramagnetic 1H NMR. This has allowed us to establish the preference of the coordination [Ni2] host for Cl- over Br-, in agreement with DFT calculations. These results show the promise of the use of metallohelicates as suitable systems for the selective encapsulation of specific anions in solution.
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Affiliation(s)
- Manuel Imperato
- Dipartimento di Scienze Chimiche e Geologiche e UdR INSTM, Università degli Studi di Modena e Reggio Emilia, via G. Campi 103, 41125 Modena, Italy.
- Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Università degli Studi di Modena e Reggio Emilia, via G. Campi 213/A, 41125 Modena, Italy
- Departament de Química Inorgànica i Orgànica, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain.
| | - Alessio Nicolini
- Dipartimento di Scienze Chimiche e Geologiche e UdR INSTM, Università degli Studi di Modena e Reggio Emilia, via G. Campi 103, 41125 Modena, Italy.
| | - Jordi Ribas-Ariño
- Departament de Química Física, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain
| | - Michał Antkowiak
- Departament de Química Inorgànica i Orgànica, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain.
- Faculty of Physics, Adam Mickiewicz University, ul. Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland
| | - Olivier Roubeau
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC and Universidad de Zaragoza, Plaza San Francisco s/n, 50009, Zaragoza, Spain
| | - Andrea Cornia
- Dipartimento di Scienze Chimiche e Geologiche e UdR INSTM, Università degli Studi di Modena e Reggio Emilia, via G. Campi 103, 41125 Modena, Italy.
| | - Valentin Novikov
- Departament de Química Inorgànica i Orgànica, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain.
- Institute of Nanoscience and Nanotechnology of the University of Barcelona (IN2UB), Barcelona, Spain
| | - Leoní A Barrios
- Departament de Química Inorgànica i Orgànica, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain.
- Institute of Nanoscience and Nanotechnology of the University of Barcelona (IN2UB), Barcelona, Spain
| | - Guillem Aromí
- Departament de Química Inorgànica i Orgànica, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain.
- Institute of Nanoscience and Nanotechnology of the University of Barcelona (IN2UB), Barcelona, Spain
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2
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Risa A, Barrios LA, Diego R, Roubeau O, Aleshin DY, Nelyubina Y, Novikov V, Teat SJ, Ribas-Ariño J, Aromí G. Engineered π⋯π interactions favour supramolecular dimers X@[FeL 3] 2 (X = Cl, Br, I): solid state and solution structure. Chem Sci 2024; 15:9047-9053. [PMID: 38903210 PMCID: PMC11186344 DOI: 10.1039/d4sc01365d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 05/23/2024] [Indexed: 06/22/2024] Open
Abstract
Ditopic bis-pyrazolylpyridine ligands usually react with divalent metal ions (M2+) to produce dinuclear triple-stranded helicates [M2L3]4+ or, via π⋯π interactions, dimers of monoatomic complexes ([ML3]2)4+. The introduction of an additional benzene ring at each end of ligand L increases the number of aromatic contacts within the supramolecular aggregate by 40%, driving the self-recognition process in an irreversible manner. Consequently, the mixing of new bis-pyrazolylquinoline L2 with FeX2 salts leads to crystallization of the tripartite high-spin assemblies (X@[Fe(L2)3]2)3+ (X = Cl, Br or I). The aggregates exhibit exceptional stability, as confirmed by a combination of paramagnetic 1H NMR techniques, demonstrating their persistence in solution. Our investigations further reveal that the guests Br- and I- are retained inside the associate in solution but Cl- is immediately released, resulting in the formation of the empty supramolecular dimer ([Fe(L2)3]2)4+.
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Affiliation(s)
- Arnau Risa
- Departament de Química Inorgànica i Orgànica, Secció Química Inorgànica, Universitat de Barcelona Barcelona Spain
| | - Leoní A Barrios
- Departament de Química Inorgànica i Orgànica, Secció Química Inorgànica, Universitat de Barcelona Barcelona Spain
- Institute of Nanoscience and Nanotechnology of the University of Barcelona (IN2UB) Barcelona Spain
| | - Rosa Diego
- Departament de Química Inorgànica i Orgànica, Secció Química Inorgànica, Universitat de Barcelona Barcelona Spain
- Institute of Nanoscience and Nanotechnology of the University of Barcelona (IN2UB) Barcelona Spain
| | - Olivier Roubeau
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza Zaragoza Spain
- Departamento de Física de la Materia Condensada, Universidad de Zaragoza Zaragoza Spain
| | - Dmitry Y Aleshin
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences 119991 Moscow Russia
| | - Yulia Nelyubina
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences 119991 Moscow Russia
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry, Russian Academy of Sciences Acad. Semenov Str. 1 Chernogolovka 142432 Russia
| | - Valentin Novikov
- Departament de Química Inorgànica i Orgànica, Secció Química Inorgànica, Universitat de Barcelona Barcelona Spain
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry, Russian Academy of Sciences Acad. Semenov Str. 1 Chernogolovka 142432 Russia
| | - Simon J Teat
- Advanced Light Source, Berkeley Laboratory 1 Cyclotron Road Berkeley California 94720 USA
| | - Jordi Ribas-Ariño
- Departament de Química Física, IQTCUB, Universitat de Barcelona Diagonal 645 08028 Barcelona Spain
| | - Guillem Aromí
- Departament de Química Inorgànica i Orgànica, Secció Química Inorgànica, Universitat de Barcelona Barcelona Spain
- Institute of Nanoscience and Nanotechnology of the University of Barcelona (IN2UB) Barcelona Spain
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3
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Barrios LA, Capó N, Boulehjour H, Reta D, Tejedor I, Roubeau O, Aromí G. Modulated spin dynamics of [Co 2] coordination helicates via differential strand composition. Dalton Trans 2024; 53:7611-7618. [PMID: 38618945 DOI: 10.1039/d4dt00629a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Coordination supramolecular chemistry provides a versatile entry into materials with functionalities of technological relevance at the nanoscale. Here, we describe how two different bis-pyrazolylpyridine ligands (L1 and L2) assemble with Co(II) ions into dinuclear triple-stranded helicates, in turn, encapsulating different anionic guests. These constructs are described as (Cl@[Co2(L1)3])3+, (SiF6@[Co2(L1)(L2)3])2+ and (ClO4@[Co2(L2)3])3+, as established by single-crystal X-ray diffraction. Extensive magnetic and calorimetric measurements, numerical treatments and theoretical calculations reveal that the individual Co(II) centers of these supramolecular entities exhibit field-induced slow relaxation of magnetization, dominated by direct and Raman mechanisms. While the small variations in the spin dynamics are not easily correlated with the evident structural differences among the three species, the specific heat measurements suggest two vibronic pathways of magnetic relaxation: one that would be associated with the host lattice and another linked with the guest.
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Affiliation(s)
- Leoní A Barrios
- Departament de Química Inorgànica i Orgànica and IN2UB, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain.
| | - Nuria Capó
- Departament de Química Inorgànica i Orgànica and IN2UB, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain.
| | - Hanae Boulehjour
- Donostia International Physics Center (DIPC), Donostia, 20018, Spain
| | - Daniel Reta
- Faculty of Chemistry, The University of the Basque Country UPV/EHU, Donostia, 20018, Spain
- Donostia International Physics Center (DIPC), Donostia, 20018, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, 48013, Spain
| | - Inés Tejedor
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC and Universidad de Zaragoza, Plaza San Francisco s/n, 50009, Zaragoza, Spain
| | - Olivier Roubeau
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC and Universidad de Zaragoza, Plaza San Francisco s/n, 50009, Zaragoza, Spain
| | - Guillem Aromí
- Departament de Química Inorgànica i Orgànica and IN2UB, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain.
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Fernández-Fariña S, Velo-Heleno I, Martínez-Calvo M, Maneiro M, Pedrido R, González-Noya AM. Schiff Bases Functionalized with T-Butyl Groups as Adequate Ligands to Extended Assembly of Cu(II) Helicates. Int J Mol Sci 2023; 24:ijms24108654. [PMID: 37239998 DOI: 10.3390/ijms24108654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 05/05/2023] [Accepted: 05/10/2023] [Indexed: 05/28/2023] Open
Abstract
The study of the inherent factors that influence the isolation of one type of metallosupramolecular architecture over another is one of the main objectives in the field of Metallosupramolecular Chemistry. In this work, we report two new neutral copper(II) helicates, [Cu2(L1)2]·4CH3CN and [Cu2(L2)2]·CH3CN, obtained by means of an electrochemical methodology and derived from two Schiff-based strands functionalized with ortho and para-t-butyl groups on the aromatic surface. These small modifications let us explore the relationship between the ligand design and the structure of the extended metallosupramolecular architecture. The magnetic properties of the Cu(II) helicates were explored by Electron Paramagnetic Resonance (EPR) spectroscopy and Direct Current (DC) magnetic susceptibility measurements.
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Affiliation(s)
- Sandra Fernández-Fariña
- Departamento de Química Inorgánica, Facultade de Química, Campus Vida, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Isabel Velo-Heleno
- Departamento de Química Inorgánica, Facultade de Química, Campus Vida, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Miguel Martínez-Calvo
- Departamento de Química Inorgánica, Facultade de Química, Campus Vida, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Marcelino Maneiro
- Departamento de Química Inorgánica, Facultade de Ciencias, Universidade de Santiago de Compostela, 27002 Lugo, Spain
| | - Rosa Pedrido
- Departamento de Química Inorgánica, Facultade de Química, Campus Vida, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Ana M González-Noya
- Departamento de Química Inorgánica, Facultade de Química, Campus Vida, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
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5
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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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6
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Aleshin DY, Diego R, Barrios LA, Nelyubina YV, Aromí G, Novikov VV. Unravelling of a [High Spin—Low Spin] ↔ [Low Spin—High Spin] Equilibrium in Spin‐Crossover Iron(II) Dinuclear Helicates Using Paramagnetic NMR Spectroscopy. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202110310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Dmitry Yu. Aleshin
- A. N. Nesmeyanov Institute of Organoelement Compounds Russian Academy of Sciences Vavilova str. 28 11999 Moscow Russia
| | - Rosa Diego
- Department de Quimica Inorganica and IN2UB Universitat de Barcelona Diagonal 647 08028 Barcelona Spain
| | - Leoní A. Barrios
- Department de Quimica Inorganica and IN2UB Universitat de Barcelona Diagonal 647 08028 Barcelona Spain
| | - Yulia V. Nelyubina
- A. N. Nesmeyanov Institute of Organoelement Compounds Russian Academy of Sciences Vavilova str. 28 11999 Moscow Russia
- Moscow Institute of Physics and Technology Institutskiy per. 9 141700 Dolgoprudny Moscow region Russia
| | - Guillem Aromí
- Department de Quimica Inorganica and IN2UB Universitat de Barcelona Diagonal 647 08028 Barcelona Spain
| | - Valentin V. Novikov
- A. N. Nesmeyanov Institute of Organoelement Compounds Russian Academy of Sciences Vavilova str. 28 11999 Moscow Russia
- Moscow Institute of Physics and Technology Institutskiy per. 9 141700 Dolgoprudny Moscow region Russia
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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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8
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Aleshin DY, Diego R, Barrios LA, Nelyubina YV, Aromí G, Novikov VV. Unravelling of a [High Spin-Low Spin] ↔ [Low Spin-High Spin] Equilibrium in Spin-Crossover Iron(II) Dinuclear Helicates Using Paramagnetic NMR Spectroscopy. Angew Chem Int Ed Engl 2021; 61:e202110310. [PMID: 34757659 DOI: 10.1002/anie.202110310] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 11/10/2021] [Indexed: 12/11/2022]
Abstract
Spin-crossover between high-spin (HS) and low-spin (LS) states of selected transition metal ions in polynuclear and polymeric compounds is behind their use as multistep switchable materials in breakthrough electronic and spintronic devices. We report the first successful attempt to observe the dynamics of a rarely found broken-symmetry spin state in binuclear complexes, which mixes the states [HS-LS] and [LS-HS] on a millisecond timescale. The slow exchange between these two states, which was identified by paramagnetic NMR spectroscopy in solutions of two spin-crossover iron(II) binuclear helicates that are amenable to molecular design, opens a path to double quantum dot cellular automata for information storage and processing.
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Affiliation(s)
- Dmitry Yu Aleshin
- A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, 11999, Moscow, Russia
| | - Rosa Diego
- Department de Quimica Inorganica and IN2UB, Universitat de Barcelona, Diagonal 647, 08028, Barcelona, Spain
| | - Leoní A Barrios
- Department de Quimica Inorganica and IN2UB, Universitat de Barcelona, Diagonal 647, 08028, Barcelona, Spain
| | - Yulia V Nelyubina
- A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, 11999, Moscow, Russia.,Moscow Institute of Physics and Technology, Institutskiy per. 9, 141700 Dolgoprudny, Moscow region, Russia
| | - Guillem Aromí
- Department de Quimica Inorganica and IN2UB, Universitat de Barcelona, Diagonal 647, 08028, Barcelona, Spain
| | - Valentin V Novikov
- A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova str. 28, 11999, Moscow, Russia.,Moscow Institute of Physics and Technology, Institutskiy per. 9, 141700 Dolgoprudny, Moscow region, Russia
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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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Giraldi E, Depallens AB, Ortiz D, Fadaei‐Tirani F, Scopelliti R, Severin K. Boronate Ester‐Capped Helicates. Chemistry 2020; 26:7578-7582. [DOI: 10.1002/chem.202001392] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Indexed: 12/30/2022]
Affiliation(s)
- Erica Giraldi
- Institut des Sciences et Ingénierie ChimiquesÉcole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Adrien B. Depallens
- Institut des Sciences et Ingénierie ChimiquesÉcole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Daniel Ortiz
- Institut des Sciences et Ingénierie ChimiquesÉcole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Farzaneh Fadaei‐Tirani
- Institut des Sciences et Ingénierie ChimiquesÉcole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Rosario Scopelliti
- Institut des Sciences et Ingénierie ChimiquesÉcole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Kay Severin
- Institut des Sciences et Ingénierie ChimiquesÉcole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
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Zhu XQ, Cao WH, Su SD, Wu XT, Sheng TL. Effects of ligand substituents on the single-molecule magnetic behavior of quinonoid-bridged dicobalt compounds. Dalton Trans 2020; 49:6738-6743. [PMID: 32373806 DOI: 10.1039/d0dt00033g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of quinonoid-bridged dicobalt compounds [(N4Co)2LX](ClO4)2 (1-4) (X = H, Cl, Br and OMe; N4 = 1,4,7,10-tetrabenzyl-1,4,7,10-tetraazacyclododecane) are synthesized and well characterized. Single crystal X-ray diffraction analyses reveal that the coordination geometry of one side Co in compounds 1-4 changes from a triangular prism to distorted octahedron with a change in the bridged-ligand substituent. Magnetic measurements show that compounds 1 and 3 exhibit single-molecule magnetic behavior. Magneto-structural analyses indicate that the difference in the relaxation barrier U between the four compounds results from the different orientations of the anisotropy axes of the two Co centers in the molecule.
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Affiliation(s)
- Xiao-Quan Zhu
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, 350002, China
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