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Wang M, Han Z, Garcia Y, Cheng P. Six-Coordinated Co II Single-Molecule Magnets: Synthetic Strategy, Structure and Magnetic Properties. Chemphyschem 2024; 25:e202400396. [PMID: 38889310 DOI: 10.1002/cphc.202400396] [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: 04/09/2024] [Revised: 06/15/2024] [Accepted: 06/17/2024] [Indexed: 06/20/2024]
Abstract
The pursuit of molecule-based magnetic memory materials contributes significantly to high-density information storage research in the frame of the ongoing information technologies revolution. Remarkable progress has been achieved in both transition metal (TM) and lanthanide based single-molecule magnets (SMMs). Notably, six-coordinated CoII SMMs hold particular research significance owing to the economic and abundant nature of 3d TM ions compared to lanthanide ions, the substantial spin-orbit coupling of CoII ions, the potential for precise control over coordination geometry, and the air-stability of coordination-saturated structures. In this review, we will summarize the progress made in six-coordinated CoII SMMs, organized by their coordination geometry and molecular structure similarity. Valuable insights, principles, and new mechanism gleaned from this research and remaining issues that need to be addressed will also be discussed to guide future optimization.
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Affiliation(s)
- Mengmeng Wang
- Institute of Condensed Matter and Nanosciences, Molecular Chemistry, Materials and Catalysis (IMCN/MOST), Université catholique de Louvain, 1348, Louvain-la-Neuve, Belgium
- Key Laboratory of Advanced Energy Materials Chemistry (MOE) and Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Zongsu Han
- Key Laboratory of Advanced Energy Materials Chemistry (MOE) and Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin, 300071, China
- Department of Chemistry, Texas A&M University, College Station, Texas, 77843, United States
| | - Yann Garcia
- Institute of Condensed Matter and Nanosciences, Molecular Chemistry, Materials and Catalysis (IMCN/MOST), Université catholique de Louvain, 1348, Louvain-la-Neuve, Belgium
| | - Peng Cheng
- Key Laboratory of Advanced Energy Materials Chemistry (MOE) and Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin, 300071, China
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2
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Biswas S, Havlicek L, Nemec I, Salitros I, Mandal L, Neugebauer P, Kuppusamy SK, Ruben M. Levamisole Based Co(II) Single-Ion Magnet. Chem Asian J 2024; 19:e202400574. [PMID: 38870468 DOI: 10.1002/asia.202400574] [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: 05/20/2024] [Revised: 06/13/2024] [Accepted: 06/13/2024] [Indexed: 06/15/2024]
Abstract
A new Co(II) complex, [Co(NCS)2(L)2] (1) has been synthesized based on levamisole (L) as a new ligand. Single-crystal X-ray diffraction analyses confirm that the Co(II) ion is having a distorted tetrahedral coordination geometry in the complex. Notably strong intramolecular S⋅⋅⋅S and S⋅⋅⋅N interactions has been confirmed by employing Quantum Theory of Atoms in Molecules (QTAIM). These intramolecular interactions occur among the sulfur and nitrogen atoms of the levamisole ligands and also the nitrogen atoms of the thiocyanate. Direct current (dc) magnetic analyses reveal presence of zero field splitting (ZFS) and large magnetic anisotropy on Co(II). Detailed ab initio ligand field theory calculations quantitatively predicted the magnitude of ZFS. Prominent field-induced single-ion magnet (SIM) behavior was observed for 1 from dynamic magnetization measurements. Slow magnetic relaxation follows an Orbach mechanism with the effective energy barrier Ueff=29.6 (7) K and relaxation time τo=1.4 (4)×10-9 s.
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Affiliation(s)
- Soumava Biswas
- Dr. Vishwanath Karad MIT World Peace University Survey No, 124, Paud Rd, Kothrud, Pune, 411038, Maharashtra, India
| | - Lubomir Havlicek
- Central European Institute of Technology, Brno University of Technology, Purkynova 656/123, 61200, Brno, Czech Republic
- Institute of Physics of Materials, Czech Academy of Sciences, Zizkova 22, 61662, Brno, Czech Republic
| | - Ivan Nemec
- Central European Institute of Technology, Brno University of Technology, Purkynova 656/123, 61200, Brno, Czech Republic
- Department of Inorganic Chemistry, Faculty of Science, Palacky University, 17. listopadu 12, 77147, Olomouc, Czech Republic
| | - Ivan Salitros
- Central European Institute of Technology, Brno University of Technology, Purkynova 656/123, 61200, Brno, Czech Republic
- Department of Inorganic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava., Bratislava, SK-81237, Slovakia
| | - Leena Mandal
- Department of Chemistry, Polba Mahavidyalaya, Polba Hooghly, PIN-712148, West Bengal, India
| | - Petr Neugebauer
- Central European Institute of Technology, Brno University of Technology, Purkynova 656/123, 61200, Brno, Czech Republic
| | - Senthil Kumar Kuppusamy
- Institute of Quantum Materials and Technologies (IQMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Mario Ruben
- Institute of Quantum Materials and Technologies (IQMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz1, 76344, Eggenstein-Leopoldshafen, Germany
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3
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Jabeur W, Korb M, Hamdi M, Holub M, Princík D, Zeleňák V, Sanchez-Coronilla A, Shalash M, Čižmár E, Naïli H. Structural, optical and magnetic properties of a new metal-organic Co II-based complex. RSC Adv 2024; 14:25048-25061. [PMID: 39135970 PMCID: PMC11317920 DOI: 10.1039/d4ra02149e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Accepted: 06/03/2024] [Indexed: 08/15/2024] Open
Abstract
A mononuclear cobalt(ii) complex [C5H8N3]2[CoCl4(C5H7N3)2] (I) was synthesized and structurally characterized. Single crystal X-ray diffraction analysis indicates that monometallic Co(ii) ions acted as coordination nodes in a distorted octahedral geometry, giving rise to a supramolecular architecture. The latter is made up of a ½ unit form composed of an anionic element [Co0.5Cl2(C5H7N3)]- and one 2-amino-4-methylpyrimidinium cation [C5H8N3]+. The crystalline arrangement of this compound adopts the sandwich form where inorganic parts are sandwiched between the organic sheets following the [100] direction. More information regarding the structure hierarchy has been supplied based on Hirshfeld surface analysis; the X⋯H (X = N, Cl) interactions play a crucial role in stabilizing the self-assembly process of I, complemented by the intervention of π⋯π electrostatic interaction created between organic entities. Thermal analyses were carried out to study the thermal behavior process. Static magnetic measurements and ab initio calculations of compound I revealed the easy-axis anisotropy character of the central Co(ii) ion. Two-channel field-induced slow-magnetic relaxation was observed; the high-frequency channel is characterized by underbarrier relaxation with U eff = 16.5 cm-1, and the low-frequency channel involves a direct relaxation process affected by the phonon-bottleneck effect.
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Affiliation(s)
- Wiem Jabeur
- Laboratory Physico Chemistry of the Solid State, Department of Chemistry, Faculty of Sciences of Sfax, Sfax University POBOX 1171 3000 Sfax Tunisia
| | - Marcus Korb
- The University of Western Australia, School of Molecular Sciences 35 Stirling Highway, Crawley Perth Western Australia 6009 Australia
| | - Mohamed Hamdi
- Department of Chemistry, College of Sciences and Arts Turaif, Northern Border University Arar Saudi Arabia
| | - Mariia Holub
- Institute of Physics, Faculty of Science, P. J. Šafárik University in Košice SK-041 54 Košice Slovakia
| | - Dávid Princík
- Department of Inorganic Chemistry, Faculty of Science, P. J. Šafárik University Košice SK-041 54 Slovakia
| | - Vladimír Zeleňák
- Department of Inorganic Chemistry, Faculty of Science, P. J. Šafárik University Košice SK-041 54 Slovakia
| | | | - Marwan Shalash
- Department of Chemistry, College of Sciences and Arts Turaif, Northern Border University Arar Saudi Arabia
| | - Erik Čižmár
- Institute of Physics, Faculty of Science, P. J. Šafárik University in Košice SK-041 54 Košice Slovakia
| | - Houcine Naïli
- Laboratory Physico Chemistry of the Solid State, Department of Chemistry, Faculty of Sciences of Sfax, Sfax University POBOX 1171 3000 Sfax Tunisia
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Yang EC, Tsai YT, Chang PY, Ozerov M, Krzystek J, Chien SY, He JX, Kuo TS, Sheu HS. Cobalt(II) Single-Ion Magnet Coordinated by Double Deprotonation of 2,2'-Bipyridine-6,6'-diol Ligands. ACS OMEGA 2024; 9:26149-26158. [PMID: 38911747 PMCID: PMC11190935 DOI: 10.1021/acsomega.4c01576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 05/22/2024] [Accepted: 05/27/2024] [Indexed: 06/25/2024]
Abstract
In this study, we synthesized a new Co(II) complex, [NMe4]2[Co(bpyO2)2] (1), using deprotonated 2,2'-bipyridine-6,6'-diol ligands (bpyO2 2-). This compound exhibits a significant zero-field splitting (D) value. The far-infrared magneto spectroscopy and high-frequency and field electron paramagnetic resonance (HFEPR) measurements indicated that compound 1 possesses D = -54.8 cm-1 and E ∼ 0 cm-1. These findings were subsequently confirmed by other experimental data, including DC magnetic susceptibilities and variable temperature and variable magnetic field reduced magnetizations. Additionally, we conducted a series of AC magnetic susceptibility measurements to investigate the kinetics of magnetization relaxation. Below 6.6 K and under zero external magnetic field, fast quantum tunneling of magnetization (QTM) dominates (∼570 Hz), and temperature-independent out-of-phase signals are observed. Above 8.1 K, temperature-dependent behavior is observed. Furthermore, we examined the AC magnetic susceptibility behavior under external magnetic fields ranging from 300 to 4000 G. The effect of QTM is significantly reduced in the presence of an external magnetic field. Temperature-dependent behavior is primarily governed by Raman relaxation. Through structural analysis of compound 1 and a series of pure nitrogen-coordinated single-ion magnets (SIMs), we propose that the oxo substituents from the double-deprotonated form of the 2,2'-bipyridine-6,6'-diol ligands donate their negative charge to the pyridine ring, forming amido anion sites. This triggers a more pronounced out-of-phase signal than that observed in pure pyridine-coordinated compounds. Moreover, we observed intermolecular interactions, including intermolecular hydrogen bonding, which, to some extent, influenced the slow relaxation of molecules. Therefore, we speculate that the slow relaxation phenomenon of compound 1 may be attributed to the combination of oxo back-donating effects and intermolecular interactions.
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Affiliation(s)
- En-Che Yang
- Department
of Chemistry, Fu-Jen Catholic University
Hsinchuang, New Taipei
City 242062, Taiwan, Republic of China
| | - Yu-Tung Tsai
- Department
of Chemistry, Fu-Jen Catholic University
Hsinchuang, New Taipei
City 242062, Taiwan, Republic of China
| | - Po-Ya Chang
- National
Synchrotron Radiation Research Center, Hsinchu 300092, Taiwan, Republic of China
| | - Mykhaylo Ozerov
- National
High Magnetic Field Laboratory, Florida
State University, Tallahassee, Florida 32310, United States
| | - Jurek Krzystek
- National
High Magnetic Field Laboratory, Florida
State University, Tallahassee, Florida 32310, United States
| | - Su-Ying Chien
- Instrumentation
Centre College of Science, National Taiwan
University, Taipei 10617, Taiwan,
Republic of China
| | - Jun-Xian He
- Department
of Chemistry, Fu-Jen Catholic University
Hsinchuang, New Taipei
City 242062, Taiwan, Republic of China
| | - Ting-Shen Kuo
- Centre
of National Taiwan Normal University, Taipei 11677, Taiwan, Republic of China
| | - Hwo-Shuenn Sheu
- National
Synchrotron Radiation Research Center, Hsinchu 300092, Taiwan, Republic of China
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5
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Potočňák I, Bukrynov O, Kliuikov A, Holub M, Vitushkina S, Samoľová E, Čižmár E, Váhovská L. Influence of the phonon-bottleneck effect and low-energy vibrational modes on the slow spin-phonon relaxation in Kramers-ions-based Cu(II) and Co(II) complexes with 4-amino-3,5-bis-(pyridin-2-yl)-1,2,4-triazole and dicyanamide. Dalton Trans 2024; 53:6950-6964. [PMID: 38567872 DOI: 10.1039/d4dt00219a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/24/2024]
Abstract
Two new complexes, bis-[4-amino-3,5-bis-(pyridin-2-yl)-1,2,4-triazole-κ2N2,N6]bis-(dicyanamide-κN8)copper(II), [Cu(abpt)2(dca)2] (1) and bis-[4-amino-3,5-bis-(pyridin-2-yl)-1,2,4-triazole-κ2N2,N6]bis-(dicyanamide-κN8)cobalt(II), [Co(abpt)2(dca)2] (2), have been prepared and magneto-structurally characterised. Single crystal studies of both complexes have shown that their crystal structures are molecular, in which the central atoms are six-coordinated in the form of a distorted octahedron by two bidentate abpt and two monodentate dca ligands. Even if both complexes have the same composition and crystallize in the same P1̄ space group, they are not isostructural. Both structures contain strong intermolecular N-H⋯N hydrogen bonds and π-π stacking interactions. IR spectra are consistent with the solved structures of both complexes and confirmed the terminal character of the dca ligands and the bidentate coordination of the abpt ligands. The analysis of the magnetic properties showed that both complexes exhibit field-induced slow spin-phonon relaxation. In both complexes, the slow spin-phonon relaxation is influenced by a severe phonon-bottleneck effect that affects the direct process, a dominant relaxation mechanism at low temperatures in both complexes. The phonon-bottleneck effect in 1 was suppressed by simply reducing the crystallite size, and further analysis of the field dependence of the relaxation time yielded the characteristic energy of vibrational modes of 11 cm-1 participating in the Raman process at low magnetic fields. The analysis of magnetic properties and ab initio calculations confirmed that 2 represents a system with a moderate uniaxial anisotropy yielding an average energy barrier of 82 cm-1 (from all four nonequivalent Co(II) sites in the structure of 2).
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Affiliation(s)
- Ivan Potočňák
- P. J. Šafárik University in Košice, Faculty of Science, Institute of Chemistry, Department of Inorganic Chemistry, Moyzesova 11, SK-041 54 Košice, Slovakia
| | - Oleksandr Bukrynov
- V. N. Karazin Kharkiv National University, Faculty of Chemistry, Department of Applied Chemistry, Svobody sq. 4, UA-61022 Kharkiv, Ukraine
| | - Andrii Kliuikov
- P. J. Šafárik University in Košice, Faculty of Science, Institute of Physics, Park Angelinum 9, SK-041 54 Košice, Slovakia
- Slovak Metrological Institute, Karloveská 63, SK-842 55 Bratislava, Slovakia
| | - Mariia Holub
- P. J. Šafárik University in Košice, Faculty of Science, Institute of Physics, Park Angelinum 9, SK-041 54 Košice, Slovakia
- Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, FR-91190 Saint-Aubin, France
| | - Svitlana Vitushkina
- V. N. Karazin Kharkiv National University, Faculty of Chemistry, Department of Applied Chemistry, Svobody sq. 4, UA-61022 Kharkiv, Ukraine
- Institute of Experimental Physics of the Slovak Academy of Sciences, Department of Materials Physics, Watsonova 47, SK-040 01 Košice, Slovakia
| | - Erika Samoľová
- Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, CZ-182 21 Prague 8, Czech Republic
| | - Erik Čižmár
- P. J. Šafárik University in Košice, Faculty of Science, Institute of Physics, Park Angelinum 9, SK-041 54 Košice, Slovakia
| | - Lucia Váhovská
- University of Veterinary Medicine and Pharmacy in Košice, Department of Chemistry, Biochemistry and Biophysics, Komenského 73, SK-041 84 Košice, Slovakia.
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Zabala-Lekuona A, Landart-Gereka A, Quesada-Moreno MM, Mota AJ, Díaz-Ortega IF, Nojiri H, Krzystek J, Seco JM, Colacio E. Zero-Field SMM Behavior Triggered by Magnetic Exchange Interactions and a Collinear Arrangement of Local Anisotropy Axes in a Linear Co 3II Complex. Inorg Chem 2023. [PMID: 37991724 DOI: 10.1021/acs.inorgchem.3c02817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
A new linear trinuclear Co(II)3 complex with a formula of [{Co(μ-L)}2Co] has been prepared by self-assembly of Co(II) ions and the N3O3-tripodal Schiff base ligand H3L, which is obtained from the condensation of 1,1,1-tris(aminomethyl)ethane and salicylaldehyde. Single X-ray diffraction shows that this compound is centrosymmetric with triple-phenolate bridging groups connecting neighboring Co(II) ions, leading to a paddle-wheel-like structure with a pseudo-C3 axis lying in the Co-Co-Co direction. The Co(II) ions at both ends of the Co(II)3 molecule exhibit distorted trigonal prismatic CoN3O3 geometry, whereas the Co(II) at the middle presents an elongated trigonal antiprismatic CoO6 geometry. The combined analysis of the magnetic data and theoretical calculations reveal strong easy-axis magnetic anisotropy for both types of Co(II) ions (|D| values higher than 115 cm-1) with the local anisotropic axes lying on the pseudo-C3 axis of the molecule. The magnetic exchange interaction between the middle and ends Co(II) ions, extracted by using either a Hamiltonian accounting for the isotropic magnetic coupling and ZFS or the Lines' model, was found to be medium to strong and antiferromagnetic in nature, whereas the interaction between the external Co(II) ions is weak antiferromagnetic. Interestingly, the compound exhibits slow relaxation of magnetization and open hysteresis at zero field and therefore SMM behavior. The significant magnetic exchange coupling found for [{Co(μ-L)}2Co] is mainly responsible for the quenching of QTM, which combined with the easy-axis local anisotropy of the CoII ions and the collinearity of their local anisotropy axes with the pseudo-C3 axis favors the observation of SMM behavior at zero field.
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Affiliation(s)
- Andoni Zabala-Lekuona
- Departamento de Química Aplicada, Facultad de Química, Universidad del País Vasco (UPV/EHU), 20018 Donostia-San Sebastián, Spain
| | - Aritz Landart-Gereka
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain
| | - María Mar Quesada-Moreno
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain
| | - Antonio J Mota
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain
| | - Ismael F Díaz-Ortega
- Institute for Materials Research, Tohoku University, Katahira, Sendai 980-8577, Japan
| | - Hiroyuki Nojiri
- Institute for Materials Research, Tohoku University, Katahira, Sendai 980-8577, Japan
| | - Jurek Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - José M Seco
- Departamento de Química Aplicada, Facultad de Química, Universidad del País Vasco (UPV/EHU), 20018 Donostia-San Sebastián, Spain
| | - Enrique Colacio
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain
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Dey A, Ali J, Moorthy S, Gonzalez JF, Pointillart F, Singh SK, Chandrasekhar V. Field induced single ion magnet behavior in Co II complexes in a distorted square pyramidal geometry. Dalton Trans 2023; 52:14807-14821. [PMID: 37791680 DOI: 10.1039/d3dt01769a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
We report three CoII-based complexes with the general formula [CoII(L)(X)2] by changing the halide/pseudo-halide ions [X = NCSe (1SeCN); Cl (2Cl) and Br (3Br)]. The obtained τ5 and CShM values confirm a distorted square pyramidal geometry around the CoII ion in all these complexes. In these three complexes, the central CoII ion is situated above the basal plane of the square pyramidal geometry. The extent of distortion from the ideal SPY-5 geometry differs upon changing the coordinating halide/pseudo-halide ion in these complexes. This essentially results in the alteration of the anisotropic parameter D and hence impacts the magnetic properties in these complexes. This phenomenon has been corroborated with the aid of theoretical investigations. All these complexes display field-induced SIM behaviour with magnetic relaxation occurring through a combination of processes depending on the applied dc magnetic field values and dilution.
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Affiliation(s)
- Atanu Dey
- Department of Chemistry, Gandhi Institute of Technology and Management (GITAM), NH 207, Nagadenehalli, Doddaballapur Taluk, Bengaluru 561203, India.
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad, 500 046, India.
| | - Junaid Ali
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad, 500 046, India.
| | - Shruti Moorthy
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, 502285, Telangana, India.
| | - Jessica Flores Gonzalez
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, 35000 Rennes, France.
| | - Fabrice Pointillart
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, 35000 Rennes, France.
| | - Saurabh Kumar Singh
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, 502285, Telangana, India.
| | - Vadapalli Chandrasekhar
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad, 500 046, India.
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
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8
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Wang M, Han Z, Gou X, Shi W, Zhang YQ, Cheng P. Alkyl Chains Modulated Magnetization Dynamics of Mononuclear Trigonal Prismatic Co II Complexes. Chemistry 2023; 29:e202301693. [PMID: 37498805 DOI: 10.1002/chem.202301693] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 07/26/2023] [Accepted: 07/27/2023] [Indexed: 07/29/2023]
Abstract
Four benzeneboron-capped mononuclear CoII complexes with different alkyl substitutions on the fourth position of phenylboronic acid were obtained. The CoII ions are all wrapped by the pocket-like ligands and located in trigonal prismatic coordination geometries. Alternating-current magnetic susceptibility measurements reveal that they show different magnetization dynamics, such as distinct relaxation rates at the same temperature, the faster QTM rates for the ethyl and propyl substituted complexes, as well as different relaxation processes. Magneto-structural correlation study reveals that the various deviations of coordination geometry of CoII ion, diverse crystal packings and possible different vibration modes of substituents caused by modifying alkyl chains are the key factors affecting the magnetization dynamics. This work demonstrates that the alkyl chains even locating far away from the metal center can have a large impact on the magnetic behavior of the CoII complex with a very rigid coordination geometry, offering a new perspective towards transition metal based single-molecule magnets.
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Affiliation(s)
- Mengmeng Wang
- Department of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry (MOE) and Frontiers Science Center for New Organic MatterCollege of Chemistry, Nankai University, Tianjin, 300071, China
| | - Zongsu Han
- Department of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry (MOE) and Frontiers Science Center for New Organic MatterCollege of Chemistry, Nankai University, Tianjin, 300071, China
| | - Xiaoshuang Gou
- Department of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry (MOE) and Frontiers Science Center for New Organic MatterCollege of Chemistry, Nankai University, Tianjin, 300071, China
| | - Wei Shi
- Department of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry (MOE) and Frontiers Science Center for New Organic MatterCollege of Chemistry, Nankai University, Tianjin, 300071, China
| | - Yi-Quan Zhang
- School of Physical Science and Technology, Nanjing Normal University, Nanjing, 210023, P. R. China
| | - Peng Cheng
- Department of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry (MOE) and Frontiers Science Center for New Organic MatterCollege of Chemistry, Nankai University, Tianjin, 300071, China
- Haihe Laboratory of Sustainable Chemical Transformations, Tianjin, 300192, China
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9
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Gupta SK, Rao SV, Demeshko S, Dechert S, Bill E, Atanasov M, Neese F, Meyer F. Air-stable four-coordinate cobalt(ii) single-ion magnets: experimental and ab initio ligand field analyses of correlations between dihedral angles and magnetic anisotropy. Chem Sci 2023; 14:6355-6374. [PMID: 37325133 PMCID: PMC10266464 DOI: 10.1039/d3sc00813d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 05/12/2023] [Indexed: 06/17/2023] Open
Abstract
For single-ion magnets (SIMs), understanding the effects of the local coordination environment and ligand field on magnetic anisotropy is key to controlling their magnetic properties. Here we present a series of tetracoordinate cobalt(ii) complexes of the general formula [FL2Co]X2 (where FL is a bidentate diamido ligand) whose electron-withdrawing -C6F5 substituents confer stability under ambient conditions. Depending on the cations X, these complexes adopt structures with greatly varying dihedral twist angle δ between the N-Co-N' chelate planes in the solid state (48.0 to 89.2°). AC and DC field magnetic susceptibility measurements show this to translate into very different magnetic properties, the axial zero-field splitting (ZFS) parameter D ranging from -69 cm-1 to -143 cm-1 with substantial or negligible rhombic component E, respectively. A close to orthogonal arrangement of the two N,N'-chelating σ- and π-donor ligands at the Co(ii) ion is found to raise the energy barrier for magnetic relaxation to above 400 K. Multireference ab initio methods were employed to describe the complexes' electronic structures, and the results were analyzed within the framework of ab initio ligand field theory to probe the nature of the metal-ligand bonding and spin-orbit coupling. A relationship between the energy gaps of the first few electronic transitions and the ZFS was established, and the ZFS was correlated with the dihedral angle δ as well as with the metal-ligand bonding variations, viz. the two angular overlap parameters eσ and eπs. These findings not only give rise to a Co(ii) SIM showing open hysteresis up to 3.5 K at a sweep rate of 30 Oe s-1, but they also provide design guidelines for Co(ii) complexes with favorable SIM signatures or even switchable magnetic relaxation properties.
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Affiliation(s)
- Sandeep K Gupta
- Institut für Anorganische Chemie, Universität Göttingen Tammannstrasse 4 37077 Göttingen Germany
| | - Shashank V Rao
- Max Planck Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
| | - Serhiy Demeshko
- Institut für Anorganische Chemie, Universität Göttingen Tammannstrasse 4 37077 Göttingen Germany
| | - Sebastian Dechert
- Institut für Anorganische Chemie, Universität Göttingen Tammannstrasse 4 37077 Göttingen Germany
| | - Eckhard Bill
- Max Planck Institute for Chemical Energy Conversion Stiftstrasse 34-36 45470 Mülheim an der Ruhr Germany
| | - Mihail Atanasov
- Max Planck Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
- Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences Akad. Georgi Bontchev Street 11 1113 Sofia Bulgaria
| | - Frank Neese
- Max Planck Institut für Kohlenforschung Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany
| | - Franc Meyer
- Institut für Anorganische Chemie, Universität Göttingen Tammannstrasse 4 37077 Göttingen Germany
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10
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Novitchi G, Shova S, Train C. Investigation by Chemical Substitution within 2p-3d-4f Clusters of the Cobalt(II) Role in the Magnetic Behavior of [vdCoLn] 2 (vd = Verdazyl Radical). Inorg Chem 2022; 61:17037-17048. [PMID: 36240010 DOI: 10.1021/acs.inorgchem.2c01742] [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
1,5-Dimethyl-3-(3'-(hydroxymethyl)-2'-pyridine)-6-oxotetrazane (H3vdpyCH2OH) or its oxidized verdazyl form (vdpyCH2OH) reacted with transition metal and/or lanthanide acetates to yield [(vdpyCH2O)2Co2Ln2(acO)8] (Ln = Y(III): ICo,Y; Gd(III): ICo,Gd), [(vdpyCH2O)2M3(acO)4] (M = Zn(II): IIZn; Co(II): IICo) and [(vdpyCH2OH)Zn(acO)2] (IIIZn) through self-assembly implying a complex-as-ligand intermediate. Single-crystal diffraction reveals that IMT,Ln are composed of 2p-3d-4f centrosymmetric clusters with verdazyl radicals at the two ends coordinated to the transition-metal ion in a tridentate mode and to the {Ln2(acO)4} lanthanide central core in a monodentate mode through its alkoxo moiety. In ICo,Gd, the transition-metal ions adopt an irregular octahedral environment, and the {Ln2(acO)4} core adopts a paddlewheel motif, whereas in ICo,Y, the transition metal is pentacoordinated, and the central core contains only two acetate bridges. Going from ICo,Y to IICo, the central {Y2(acO)4} core is replaced by an axially compressed octahedral cobalt(II) center, whereas the outer parts of the molecule remain still. The dc magnetic studies revealed that the alternate π-stacking of the verdazyl radicals in IIZn led to the formation of alternate antiferromagnetically coupled 1D chains with Jvd-vd = -8.2(1) cm-1 and Jvd-vd' = -7.6(1) cm-1 (-2J convention). In ICo,Y, a complex fitting procedure allowed us to retrieve a complete set of magnetic parameters to take into account both the magnetic anisotropy of the cobalt(II) centers and intra- and inter-molecular exchange effects. For ICo,Y, it led to gCo = 2.13(4), DCo = 100(2) cm-1, ECo = 19.9(5) cm-1, JCo-vd = +26.5(4) cm-1, and Jvd-vd = -7.95(4) cm-1. ac magnetic susceptibility of ICo,Y, ICo,Gd and IICo did not reveal any slow relaxation of the magnetization even when a dc external magnetic field up to 2000 Oe was applied.
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Affiliation(s)
- Ghénadie Novitchi
- Laboratoire National des Champs Magnétiques Intenses (LNCMI) Université Grenoble Alpes, INSA Toulouse, Université Toulouse Paul Sabatier, EMFL, CNRS F-38042 Grenoble, France
| | - Sergiu Shova
- "Petru Poni" Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, 700487 Iasi, Romania
| | - Cyrille Train
- Laboratoire National des Champs Magnétiques Intenses (LNCMI) Université Grenoble Alpes, INSA Toulouse, Université Toulouse Paul Sabatier, EMFL, CNRS F-38042 Grenoble, France
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11
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Field-Induced Slow Magnetic Relaxation in Co II Cyclopropane-1,1-dicarboxylates. Molecules 2022; 27:molecules27196537. [PMID: 36235074 PMCID: PMC9572064 DOI: 10.3390/molecules27196537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 09/23/2022] [Accepted: 09/29/2022] [Indexed: 11/07/2022] Open
Abstract
New CoII substituted malonate field-induced molecular magnets {[Rb6Co3(cpdc)6(H2O)12]∙6H2O}n (1) and [Cs2Co(cpdc)2(H2O)6]n (2) (where cpdc2− stands for cyclopropane-1,1-dicarboxylic acid dianions) were synthesized. Both compounds contain mononuclear bischelate fragments {CoII(cpdc)2(H2O)2}2− where the quasi-octahedral cobalt environment (CoO6) is complemented by water molecules in apical positions. The alkali metal atoms play the role of connectors between the bischelate fragments to form 3D and 2D polymeric structures for 1 and 2, respectively. Analysis of dc magnetic data using the parametric Griffith Hamiltonian for high-spin CoII supported by ab initio calculations revealed that both compounds have an easy axis of magnetic anisotropy. Compounds 1 and 2 exhibit slow magnetic relaxation under an external magnetic field (HDC = 1000 and 1500 Oe, respectively).
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12
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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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13
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Field-Induced Single Molecule Magnetic Behavior of Mononuclear Cobalt(II) Schiff Base Complex Derived from 5-Bromo Vanillin. INORGANICS 2022. [DOI: 10.3390/inorganics10080105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
A mononuclear Co(II) complex of a Schiff base ligand derived from 5-Bromo-vanillin and 4-aminoantipyrine, that has a compressed tetragonal bipyramidal geometry and exhibiting field-induced slow magnetic relaxation, has been synthesized and characterized by single crystal X-ray diffraction, elemental analysis and molecular spectroscopy. In the crystal packing, a hydrogen-bonded dimer structural topology has been observed with two distinct metal centers having slightly different bond parameters. The complex has been further investigated for its magnetic nature on a SQUID magnetometer. The DC magnetic data confirm that the complex behaves as a typical S = 3/2 spin system with a sizable axial zero-field splitting parameter D/hc = 38 cm−1. The AC susceptibility data reveal that the relaxation time for the single-mode relaxation process is τ = 0.16(1) ms at T = 2.0 K and BDC = 0.12 T.
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14
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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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15
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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: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [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. Graphical abstract
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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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16
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Lv W, Cui HH, Chen L, Zhang YQ, Chen XT, Wang Z, Ouyang ZW, Xue ZL. Magnetic anisotropy of two tetrahedral Co(II)-halide complexes with triphenylphosphine ligands. Dalton Trans 2022; 51:7530-7538. [PMID: 35506535 DOI: 10.1039/d2dt00121g] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recently, the choice of ligand and geometric control of mononuclear complexes, which can affect the relaxation pathways and blocking temperature, have received wide attention in the field of single-ion magnets (SIMs). To find out the influence of the coordination environment on SIMs, two four-coordinate mononuclear Co(II) complexes [NEt4][Co(PPh3)X3] (X = Cl-, 1; Br-, 2) have been synthesized and studied by X-ray single crystallography, magnetic measurements, high-frequency and -field EPR (HF-EPR) spectroscopy and theoretical calculations. Both complexes are in a cubic space group Pa3̄ (No. 205), containing a slightly distorted tetrahedral moiety with crystallographically imposed C3v symmetry through the [Co(PPh3)X3]- anion. The direct-current (dc) magnetic data and HF-EPR spectroscopy indicated the anisotropic S = 3/2 spin ground states of the Co(II) ions with the easy-plane anisotropy for 1 and 2. Ab initio calculations were performed to confirm the positive magnetic anisotropies of 1 and 2. Frequency- and temperature-dependent alternating-current (ac) magnetic susceptibility measurements revealed slow magnetic relaxation for 1 and 2 at an applied dc field. Finally, the magnetic properties of 1 and 2 were compared to those of other Co(II) complexes with a [CoAB3] moiety.
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Affiliation(s)
- Wei Lv
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
| | - Hui-Hui Cui
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
| | - Lei Chen
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, China
| | - Yi-Quan Zhang
- Jiangsu Key Laboratory for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing 210023, China
| | - Xue-Tai Chen
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
| | - Zhenxing Wang
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zhong-Wen Ouyang
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zi-Ling Xue
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA
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17
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Lou YS, Lin BR, Wu CM, Chien SY, Yang EC. Phonon-induced relaxation mechanisms are changed by a chelating effect in a Co II single-ion magnet. Dalton Trans 2022; 51:6646-6653. [PMID: 35403640 DOI: 10.1039/d1dt03515k] [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
It is well known that phonon-induced relaxation processes play a significant role in accelerating magnetization relaxation in the low-temperature regime. Unfortunately, many SIMs (single-ion magnets) suffer from being quenched by these mechanisms such that neither out-of-phase signals nor magnetization hysteresis can be readily observed. Nevertheless, because it involves molecular motions at low-frequency (low-energy) levels, methods for synthetically controlling this factor have not yet been addressed by chemists. In this study, we prepared a series of three compounds in which one contains a rigid chelating ligand, and the other two contain analogous ligands that can coordinate more liberally. To our surprise, compound 1, with a rigid chelating ligand, displayed promising SIM behavior with out-of-phase signals up to 11 K in a zero d.c. magnetic field at an a.c. frequency of 1000 Hz. The other two (2 and 3) with dangling ligands failed to show significant out-of-phase signals until an extra d.c. field was applied. The results of magnetization relaxation studies suggest that the phonon-induced relaxation processes play an essential role in 2 and 3, even at very low temperatures. Nevertheless, the rigid chelating ligand in 1 prevents the molecule from being involved in phonon-induced relaxation processes that seriously interfere with the magnetization relaxation up to 5.6 K. Therefore, we concluded that the presence of a rigid chelating ligand can efficiently change the phonon-induced relaxation processes at low temperatures.
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Affiliation(s)
- Yu-Siang Lou
- Department of Chemistry, Fu-Jen Catholic University, Hsinchuang, New Taipei City, 24205, Taiwan, Republic of China.
| | - Bo-Ruei Lin
- Department of Chemistry, Fu-Jen Catholic University, Hsinchuang, New Taipei City, 24205, Taiwan, Republic of China.
| | - Chen-Ming Wu
- Department of Chemistry, Fu-Jen Catholic University, Hsinchuang, New Taipei City, 24205, Taiwan, Republic of China.
| | - Su-Ying Chien
- Instrumentation Centre, College of Science, National Taiwan University, Taipei, 10672, Taiwan, Republic of China
| | - En-Che Yang
- Department of Chemistry, Fu-Jen Catholic University, Hsinchuang, New Taipei City, 24205, Taiwan, Republic of China.
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18
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Plyuta N, Petrusenko SR, Kokozay V, Cauchy T, Lloret F, Julve M, Cano J, Avarvari N. Field-induced mononuclear cobalt(II) single-molecule magnet (SMM) based on a benzothiadiazole-ortho-vanillin ligand. Dalton Trans 2022; 51:4760-4771. [DOI: 10.1039/d1dt04274b] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A unique π-conjugated benzothiadiazole-ortho-vanillin ligand (HL), characterized by single crystal X-ray diffraction and DFT calculations, has been prepared by condensation between 4-amino-benzothiadiazole (BTD) and ortho-vanillin. Its reaction with cobalt(II) acetate...
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19
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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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20
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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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21
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Jie X, Li J, Daniliuc CG, Wübker AL, Hansen MR, Eckert H, Mück-Lichtenfeld C, Kehr G, Erker G. The Bis(η 6 -benzene)lithium Cation: A Fundamental Main-Group Organometallic Species. Angew Chem Int Ed Engl 2021; 60:22879-22884. [PMID: 34363618 DOI: 10.1002/anie.202108376] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 08/04/2021] [Indexed: 01/20/2023]
Abstract
The synthesis and characterization of the bis(η6 -benzene)lithium cation, the benzene metallocene of the lightest metal, is reported. The boron compound FmesBCl2 [Fmes: 2,4,6-tris(trifluoromethyl)phenyl] reacted with three molar equivalents of the lithio-acetylene reagent Li-C≡C-Fmxyl [Fmxyl: 3,5-bis(trifluoromethyl)phenyl]. Subsequent crystallization from benzene gave the [bis(η6 -benzene)Li]+ cation with the [{FmesB(-C≡C-Fmxyl)3 }2 Li]- anion. This parent [(arene)2 Li]+ cation shows an eclipsed arrangement of the pair of benzene ligands at the central lithium cation with uniform carbon-lithium bond lengths. The corresponding [(η6 -toluene)2 Li]+ and [(η6 -durene)2 Li]+ containing salts were similarly prepared. The bis(arene)lithium cations were characterized by X-ray diffraction, by solid-state 7 Li MAS NMR spectroscopy and their bonding features were analyzed by DFT calculations.
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Affiliation(s)
- Xiaoming Jie
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany
| | - Jun Li
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany
| | - Constantin G Daniliuc
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany
| | - Anna-Lena Wübker
- Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 28, 48149, Münster, Germany
| | - Michael Ryan Hansen
- Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 28, 48149, Münster, Germany
| | - Hellmut Eckert
- Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 28, 48149, Münster, Germany
| | - Christian Mück-Lichtenfeld
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany
| | - Gerald Kehr
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany
| | - Gerhard Erker
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany
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22
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Jie X, Li J, Daniliuc CG, Wübker A, Hansen MR, Eckert H, Mück‐Lichtenfeld C, Kehr G, Erker G. The Bis(η
6
‐benzene)lithium Cation: A Fundamental Main‐Group Organometallic Species. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202108376] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Xiaoming Jie
- Organisch-Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
| | - Jun Li
- Organisch-Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
| | - Constantin G. Daniliuc
- Organisch-Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
| | - Anna‐Lena Wübker
- Institut für Physikalische Chemie Westfälische Wilhelms-Universität Münster Corrensstraße 28 48149 Münster Germany
| | - Michael Ryan Hansen
- Institut für Physikalische Chemie Westfälische Wilhelms-Universität Münster Corrensstraße 28 48149 Münster Germany
| | - Hellmut Eckert
- Institut für Physikalische Chemie Westfälische Wilhelms-Universität Münster Corrensstraße 28 48149 Münster Germany
| | - Christian Mück‐Lichtenfeld
- Organisch-Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
| | - Gerald Kehr
- Organisch-Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
| | - Gerhard Erker
- Organisch-Chemisches Institut Westfälische Wilhelms-Universität Münster Corrensstraße 40 48149 Münster Germany
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23
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Bhowmick I, Newell BS, Shores MP. A systematic study of the influence of ligand field on the slow magnetic dynamics of Co(ii)-diimine compounds. Dalton Trans 2021; 50:10737-10748. [PMID: 34269774 DOI: 10.1039/d0dt01597k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein we report heteroleptic Co(ii) diimine complexes [Co(H2bip)2Cl2] (1), [Co(H2bip)2Br2] (2), [Co(H2bip)3]Br2·1MeOH (3) and [Co(H2bip)2(Me2bpy)]Br2·(MeCN)0.5·(H2O)0.25 (4) (H2bip = 2,2'-bi-1,4,5,6-tetrahydropyrimidine, bpy = 2,2'-dipyridyl, Me2bpy = 4,4'-Me-2,2'-dipyridyl), purposefully prepared to enable a systematic study of magnetic property changes arising from the increase of overall ligand field from σ/π-donor chlorido (1) to π-acceptor 4,4'Me-2,2'bpy (4). The presence of axial and rhombic anisotropy (D and E) of these compounds is sufficient to allow 1-4 to show field-induced slow relaxation of magnetization. Interestingly, we found as the effective ligand field is increased in the series, rhombicity (E/D) decreases, and the magnetic relaxation profile changes significantly, where relaxation of magnetization at a specific temperature becomes gradually faster. We performed mechanistic analyses of the temperature dependence of magnetic relaxation times considering Orbach relaxation processes, Raman-like relaxation and quantum tunnelling of magnetization (QTM). The effective energy barrier of the Orbach relaxation process (Ueff) is largest in compound 1 (19.2 cm-1) and gradually decreases in the order 1 > 2 > 3 > 4 giving a minimum value in compound 4 (8.3 cm-1), where the Raman-like mechanism showed the possibility of different types of phonon activity below and above ∼2.5 K. As a precursor of 1, the tetrahedral complex [Co(H2bip)Cl2] (1a) was also synthesized and structurally and magnetically characterized: this compound exhibits slow relaxation of magnetization under an applied dc field (1800 Oe) with a record slow relaxation time of 3.39 s at 1.8 K.
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Affiliation(s)
- Indrani Bhowmick
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872, USA.
| | - Brian S Newell
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872, USA. and Analytical Resources Core, Center for Materials and Molecular Analysis, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Matthew P Shores
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872, USA.
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24
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Kharwar AK, Mondal A, Sarkar A, Rajaraman G, Konar S. Modulation of Magnetic Anisotropy and Exchange Interaction in Phenoxide-Bridged Dinuclear Co(II) Complexes. Inorg Chem 2021; 60:11948-11956. [PMID: 34314144 DOI: 10.1021/acs.inorgchem.1c00956] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report a new class of four dimeric Co(II) complexes [Co2(bbpen)(X)2] (H2bbpen = N,N'-bis(2-hydroxybenzyl)-N,N'-bis(2-methylpyridyl)ethylenediamine) [X- = SCN (1), Cl (2), Br (3), and I (4)] with different coordination geometry of two Co(II) centers (trigonal-prismatic and pseudo-tetrahedral) and their magnetic study. Interestingly, the two Co(II) centers show two different types of magnetic anisotropy. State of the art ab initio CASSCF analysis reveals that the six-coordinate or the trigonal-prismatic Co(II) center possesses a consistently large negative axial zero-field splitting (negative D) parameter (∼-60 cm-1), while the four-coordinate or the pseudo-tetrahedral Co(II) center exhibits a range of D values from +13 to -23 cm-1. Ab initio calculations employing the lines model were used to estimate the magnetic exchange as both the Co(II) centers possess significant magnetic anisotropy. All the complexes display rare ferromagnetic interaction, and the strength of this interaction decreases as the ligand field on the pseudo-tetrahedral Co(II) center decreases from SCN- > Cl- > Br- > I-.
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Affiliation(s)
- Ajit Kumar Kharwar
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Bhopal, Bypass Road, Bhauri, Bhopal 462066, India
| | - Arpan Mondal
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Bhopal, Bypass Road, Bhauri, Bhopal 462066, India
| | - Arup Sarkar
- Department of Chemistry, Indian Institute of Technology, Bombay, Powai, Mumbai 400076, India
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology, Bombay, Powai, Mumbai 400076, India
| | - Sanjit Konar
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Bhopal, Bypass Road, Bhauri, Bhopal 462066, India
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25
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Cirulli M, Salvadori E, Zhang Z, Dommett M, Tuna F, Bamberger H, Lewis JEM, Kaur A, Tizzard GJ, van Slageren J, Crespo‐Otero R, Goldup SM, Roessler MM. Rotaxane Co II Complexes as Field-Induced Single-Ion Magnets. Angew Chem Int Ed Engl 2021; 60:16051-16058. [PMID: 33901329 PMCID: PMC8361961 DOI: 10.1002/anie.202103596] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Indexed: 12/02/2022]
Abstract
Mechanically chelating ligands have untapped potential for the engineering of metal ion properties. Here we demonstrate this principle in the context of CoII -based single-ion magnets. Using multi-frequency EPR, susceptibility and magnetization measurements we found that these complexes show some of the highest zero field splittings reported for five-coordinate CoII complexes to date. The predictable coordination behaviour of the interlocked ligands allowed the magnetic properties of their CoII complexes to be evaluated computationally a priori and our combined experimental and theoretical approach enabled us to rationalize the observed trends. The predictable magnetic behaviour of the rotaxane CoII complexes demonstrates that interlocked ligands offer a new strategy to design metal complexes with interesting functionality.
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Affiliation(s)
- Martina Cirulli
- School of Biological and Chemical SciencesQueen Mary University of LondonMile End RoadLondonE1 4NSUK
| | - Enrico Salvadori
- School of Biological and Chemical SciencesQueen Mary University of LondonMile End RoadLondonE1 4NSUK
- Department of ChemistryUniversity of TorinoVia Giuria 710125TorinoItaly
| | - Zhi‐Hui Zhang
- ChemistryUniversity of SouthamptonHighfieldSO 17 1BJUK
| | - Michael Dommett
- School of Biological and Chemical SciencesQueen Mary University of LondonMile End RoadLondonE1 4NSUK
| | - Floriana Tuna
- Department of Chemistry and Photon Science InstituteUniversity of ManchesterOxford RoadManchesterM13 0PLUK
| | - Heiko Bamberger
- Institut für Physikalische ChemieUniversität StuttgartPfaffenwaldring 5570569StuttgartGermany
| | - James E. M. Lewis
- ChemistryUniversity of SouthamptonHighfieldSO 17 1BJUK
- Department of ChemistryImperial College LondonMolecular Sciences Research HubWood LaneLondonW12 0BZUK
| | | | - Graham J. Tizzard
- EPSRC National Crystallographic ServiceUniversity of SouthamptonHighfieldSouthamptonSO17 1BJUK
| | - Joris van Slageren
- Institut für Physikalische ChemieUniversität StuttgartPfaffenwaldring 5570569StuttgartGermany
| | - Rachel Crespo‐Otero
- School of Biological and Chemical SciencesQueen Mary University of LondonMile End RoadLondonE1 4NSUK
| | | | - Maxie M. Roessler
- School of Biological and Chemical SciencesQueen Mary University of LondonMile End RoadLondonE1 4NSUK
- Department of ChemistryImperial College LondonMolecular Sciences Research HubWood LaneLondonW12 0BZUK
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26
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Cirulli M, Salvadori E, Zhang Z, Dommett M, Tuna F, Bamberger H, Lewis JEM, Kaur A, Tizzard GJ, Slageren J, Crespo‐Otero R, Goldup SM, Roessler MM. Rotaxane Co
II
Complexes as Field‐Induced Single‐Ion Magnets. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202103596] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Martina Cirulli
- School of Biological and Chemical Sciences Queen Mary University of London Mile End Road London E1 4NS UK
| | - Enrico Salvadori
- School of Biological and Chemical Sciences Queen Mary University of London Mile End Road London E1 4NS UK
- Department of Chemistry University of Torino Via Giuria 7 10125 Torino Italy
| | - Zhi‐Hui Zhang
- Chemistry University of Southampton Highfield SO 17 1BJ UK
| | - Michael Dommett
- School of Biological and Chemical Sciences Queen Mary University of London Mile End Road London E1 4NS UK
| | - Floriana Tuna
- Department of Chemistry and Photon Science Institute University of Manchester Oxford Road Manchester M13 0PL UK
| | - Heiko Bamberger
- Institut für Physikalische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - James E. M. Lewis
- Chemistry University of Southampton Highfield SO 17 1BJ UK
- Department of Chemistry Imperial College London Molecular Sciences Research Hub Wood Lane London W12 0BZ UK
| | - Amanpreet Kaur
- Chemistry University of Southampton Highfield SO 17 1BJ UK
| | - Graham J. Tizzard
- EPSRC National Crystallographic Service University of Southampton Highfield Southampton SO17 1BJ UK
| | - Joris Slageren
- Institut für Physikalische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Rachel Crespo‐Otero
- School of Biological and Chemical Sciences Queen Mary University of London Mile End Road London E1 4NS UK
| | | | - Maxie M. Roessler
- School of Biological and Chemical Sciences Queen Mary University of London Mile End Road London E1 4NS UK
- Department of Chemistry Imperial College London Molecular Sciences Research Hub Wood Lane London W12 0BZ UK
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27
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Palacios-Corella M, García-López V, Sánchez-Sánchez C, Clemente-Juan JM, Clemente-León M, Coronado E. Insertion of single-ion magnets based on mononuclear Co(II) complexes into ferromagnetic oxalate-based networks. Dalton Trans 2021; 50:5931-5942. [PMID: 33949535 DOI: 10.1039/d1dt00595b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The 1 : 2 and 1 : 1 Co(ii) complexes of the L ligand (L = 6-(3,5-diamino-2,4,6-triazinyl)2,2'-bipyridine) with formulas [CoII(L)2](ClO4)2·0.5MeCN·Et2O (1) and [CoII(L)(CH3CN)2(H2O)](ClO4)2·MeCN (2) have been prepared. The structural and magnetic characterization of the two compounds shows that they contain octahedral high-spin Co(ii) and present a field-induced slow relaxation of the magnetization. 1 has been inserted into a bimetallic oxalate-based network leading to a novel achiral 3D compound of formula [CoII(L)2][MnIICrIII(ox)3]2·(solvate) (3) exhibiting ferromagnetic ordering below 4.6 K. EPR measurements suggest a weak magnetic coupling between the two sublattices.
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Affiliation(s)
- M Palacios-Corella
- Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, C/Catedrático José Beltrán 2, 46980 Paterna, Spain.
| | - V García-López
- Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, C/Catedrático José Beltrán 2, 46980 Paterna, Spain.
| | - C Sánchez-Sánchez
- Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, C/Catedrático José Beltrán 2, 46980 Paterna, Spain.
| | - J M Clemente-Juan
- Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, C/Catedrático José Beltrán 2, 46980 Paterna, Spain.
| | - M Clemente-León
- Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, C/Catedrático José Beltrán 2, 46980 Paterna, Spain.
| | - E Coronado
- Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, C/Catedrático José Beltrán 2, 46980 Paterna, Spain.
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28
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Guo Z, Deng YF, Pikramenou Z, Dunbar KR, Zhang YZ. Strong Coupling and Slow Relaxation of the Magnetization for an Air-Stable [Co 4] Square with Both Tetrazine Radicals and Azido Bridges. Inorg Chem 2021; 60:3651-3656. [PMID: 33656338 DOI: 10.1021/acs.inorgchem.0c03158] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Introducing both tetrazine radical and azido bridges afforded two air-stable square complexes [MII4(bpztz•-)4(N3)4] (MII = Zn2+, 1; Co2+, 2; bpztz = 3,6-bis(3,5-dimethylpyrazolyl)-1,2,4,5-tetrazine), where the metal ions are cobridged by μ1,1-azido bridges and tetrazine radicals. Magnetic studies revealed strong antiferromagnetic metal-radical interaction with a coupling constant of -64.7 cm-1 in the 2J formalism in 2. Remarkably, 2 exhibits slow relaxation of magnetization with an effective barrier for spin reverse of 96 K at zero applied field.
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Affiliation(s)
- Zhilin Guo
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China.,School of Chemistry, The University of Birmingham, Edgbaston B15 2TT, United Kingdom
| | - Yi-Fei Deng
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
| | - Zoe Pikramenou
- School of Chemistry, The University of Birmingham, Edgbaston B15 2TT, United Kingdom
| | - Kim R Dunbar
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Yuan-Zhu Zhang
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
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29
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Świtlicka A, Machura B, Cano J, Lloret F, Julve M. A Study of the Lack of Slow Magnetic Relaxation in Mononuclear Trigonal Bipyramidal Cobalt(II) Complexes. ChemistrySelect 2021. [DOI: 10.1002/slct.202100061] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Anna Świtlicka
- Department Of Crystallography, Institute of Chemistry University of Silesia 9th Szkolna St., 40–006 Katowice Poland
| | - Barbara Machura
- Department Of Crystallography, Institute of Chemistry University of Silesia 9th Szkolna St., 40–006 Katowice Poland
| | - Joan Cano
- Department of Química Inorgànica/Instituto de Ciencia Molecular (ICMol) Facultat de Quimica de la Universitat de València C/ Catedrático Jose Beltrán 2 46980 Paterna, València Spain
| | - Francesc Lloret
- Department of Química Inorgànica/Instituto de Ciencia Molecular (ICMol) Facultat de Quimica de la Universitat de València C/ Catedrático Jose Beltrán 2 46980 Paterna, València Spain
| | - Miguel Julve
- Department of Química Inorgànica/Instituto de Ciencia Molecular (ICMol) Facultat de Quimica de la Universitat de València C/ Catedrático Jose Beltrán 2 46980 Paterna, València Spain
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30
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Zhang C, Cheng Z, Tan P, Lv W, Cui H, Chen L, Cai X, Zhao Y, Yuan A. Tuning the ligand field in seven-coordinate Dy( iii) complexes to perturb single-ion magnet behavior. NEW J CHEM 2021. [DOI: 10.1039/d1nj00734c] [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
Two mononuclear seven-coordinate Dy(iii) complexes with different strengths of ligand fields exhibit different slow magnetic relaxations.
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Affiliation(s)
- Chunyang Zhang
- School of Environmental and Chemical Engineering
- Jiangsu University of Science and Technology
- Zhenjiang 212003
- P. R. China
| | - Zhijie Cheng
- School of Environmental and Chemical Engineering
- Jiangsu University of Science and Technology
- Zhenjiang 212003
- P. R. China
| | - Pengfei Tan
- School of Environmental and Chemical Engineering
- Jiangsu University of Science and Technology
- Zhenjiang 212003
- P. R. China
| | - Wei Lv
- State Key Laboratory of Coordination Chemistry
- School of Chemistry and Chemical Engineering
- Nanjing University
- Nanjing 210093
- P. R. China
| | - Huihui Cui
- School of Chemistry and Chemical Engineering
- Nantong University
- Nantong 226019
- P. R. China
| | - Lei Chen
- School of Environmental and Chemical Engineering
- Jiangsu University of Science and Technology
- Zhenjiang 212003
- P. R. China
| | - Xingwei Cai
- School of Environmental and Chemical Engineering
- Jiangsu University of Science and Technology
- Zhenjiang 212003
- P. R. China
| | - Yuyuan Zhao
- School of Medical Technology
- Zhenjiang College
- Zhenjiang 212003
- P. R. China
| | - Aihua Yuan
- School of Environmental and Chemical Engineering
- Jiangsu University of Science and Technology
- Zhenjiang 212003
- P. R. China
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31
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Cui HH, Ding MM, Zhang XD, Lv W, Zhang YQ, Chen XT, Wang Z, Ouyang ZW, Xue ZL. Magnetic anisotropy in square pyramidal cobalt(II) complexes supported by a tetraazo macrocyclic ligand. Dalton Trans 2020; 49:14837-14846. [PMID: 33034595 DOI: 10.1039/d0dt01954b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two five-coordinate mononuclear Co(ii) complexes [Co(12-TMC)X][B(C6H5)4] (L = 1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecane (12-TMC), X = Cl- (1), Br- (2)) have been studied by X-ray single crystallography, magnetic measurements, high-frequency and -field EPR (HF-EPR) spectroscopy and theoretical calculations. Both complexes have a distorted square pyramidal geometry with the Co(ii) ion lying above the basal plane constrained by the rigid tetradentate macrocyclic ligand. In contrast to the reported five-coordinate Co(ii) complex [Co(12-TMC)(NCO)][B(C6H5)4] (3) exhibiting easy-axis anisotropy, an easy-plane magnetic anisotropy was found for 1 and 2via the analyses of the direct-current magnetic data and HF-EPR spectroscopy. Frequency- and temperature-dependent alternating-current magnetic susceptibility measurements demonstrated that complexes 1 and 2 show slow magnetic relaxation at an applied dc field. Ab initio calculations were performed to reveal the impact of the terminal ligands on the nature of the magnetic anisotropies of this series of five-coordinate Co(ii) complexes.
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Affiliation(s)
- Hui-Hui Cui
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
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32
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Wu H, Gao L, Zhang J, Zhai L, Gao T, Niu X, Hu T. Syntheses, characterization, and slow magnetic relaxation or luminescence properties of three new 2D coordination polymers. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2020.128613] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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33
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Sarkar A, Dey S, Rajaraman G. Role of Coordination Number and Geometry in Controlling the Magnetic Anisotropy in Fe II , Co II , and Ni II Single-Ion Magnets. Chemistry 2020; 26:14036-14058. [PMID: 32729641 DOI: 10.1002/chem.202003211] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Indexed: 12/22/2022]
Abstract
Since the last decade, the focus in the area of single-molecule magnets (SMMs) has been shifting constructively towards the development of single-ion magnets (SIMs) based on transition metals and lanthanides. Although ground-breaking results have been witnessed for DyIII -based SIMs, significant results have also been obtained for some mononuclear transition metal SIMs. Among others, studies based on CoII ion are very prominent as they often exhibit high magnetic anisotropy or zero-field splitting parameters and offer a large barrier height for magnetisation reversal. Although CoII possibly holds the record for having the largest number of zero-field SIMs known for any transition metal ion, controlling the magnetic anisotropy in these systems are is still a challenge. In addition to the modern spectroscopic techniques, theoretical studies, especially ab initio CASSCF/NEVPT2 approaches, have been used to uncover the electronic structure of various CoII SIMs. In this article, with some selected examples, the aim is to showcase how varying the coordination number from two to eight, and the geometry around the CoII centre alters the magnetic anisotropy. This offers some design principles for the experimentalists to target new generation SIMs based on the CoII ion. Additionally, some important FeII /FeIII and NiII complexes exhibiting large magnetic anisotropy and SIM properties are also discussed.
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Affiliation(s)
- Arup Sarkar
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - Sourav Dey
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India
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34
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Saber MR, Przyojski JA, Tonzetich ZJ, Dunbar KR. Slow magnetic relaxation in cobalt N-heterocyclic carbene complexes. Dalton Trans 2020; 49:11577-11582. [PMID: 32749418 DOI: 10.1039/d0dt02286a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The combined experimental and theoretical investigation of the magnetic properties of the cobalt(ii) NHC complexes (NHC = N-heterocyclic carbene); [Co(CH2SiMe3)2(IPr)] (1), [CoCl2(IMes)2] (2) and [Co(CH3)2(IMes)2] (3) revealed a large easy plane anisotropy for 1 (D = +73.7 cm-1) and a moderate easy axis anisotropy for 2 (D = -7.7 cm-1) due to significant out-of-state spin-orbit coupling. Dynamic magnetic measurements revealed slow relaxation of the magnetization for 1 (Ueff = 22.5 K, τ0 = 3 × 10-7 s, 1000 Oe) and for 2 (Ueff = 20.2 K, τ0 = 1.73 × 10-8 s, 1500 Oe). The molecular origin of the slow relaxation phenomena was further supported by the retention of AC signal in 10% solutions in 2-MeTHF which reveals a second zero field AC signal in 1 at higher frequencies. Compound 3 was found to be an S = 1/2 system.
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Affiliation(s)
- Mohamed R Saber
- Department of Chemistry, Texas A&M University, College Station, TX 77842-3012, USA. and Chemistry Department, Faculty of Science, Fayoum University, Fayoum 63514, Egypt
| | - Jacob A Przyojski
- Department of Chemistry, University of Texas at San Antonio (UTSA), San Antonio, TX 78249, USA
| | - Zachary J Tonzetich
- Department of Chemistry, University of Texas at San Antonio (UTSA), San Antonio, TX 78249, USA
| | - Kim R Dunbar
- Department of Chemistry, Texas A&M University, College Station, TX 77842-3012, USA.
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35
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Paul A, Viciano-Chumillas M, Puschmann H, Cano J, Manna SC. Field-induced slow magnetic relaxation in mixed valence di- and tri-nuclear Co II-Co III complexes. Dalton Trans 2020; 49:9516-9528. [PMID: 32608402 DOI: 10.1039/d0dt00588f] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two novel mixed valence CoII-CoIII complexes, namely [CoIICoIII(L1)(ab)(mb)2(H2O)]·dmf (1) and [CoCoII(L2)4(H2O)4]·2H2O (2) [H2L1 = (E)-2-((1-hydroxybutan-2-ylimino)methyl)-6-methoxyphenol, ab = 2-amino-butan-1-ol anion, mb = p-methyl benzoate, H2L2 = 3-((2-hydroxy-3-methoxy-benzylidene)-amino)-propionic acid, and dmf = N,N-dimethyl-formamide], were synthesized and characterized by single crystal X-ray diffraction and magnetic studies at low temperature. The structure determination reveals that both complexes belong to the monoclinic system with P21/c (1) and I2/a (2) space groups. Complex 1 is a dinuclear CoIIICoII compound with distorted octahedral cobalt centers showing different coordination environments. In 2, a bent trinuclear CoCoII complex, the coordination environments around the two terminal CoIII sites are alike, whereas they are different in the central CoII ion. Alternating current/direct current (ac/dc) magnetic studies revealed that both complexes show field-induced slow magnetic relaxation. The dc magnetic susceptibility and magnetization data were analyzed with the following Hamiltonianwhere D and E are the axial and rhombic zero-field splitting (zfs) parameters, respectively, and a good agreement between experimental and simulated results was found using the parameters g⊥ = 2.585, g∥ = 2.437, D = +98.1 cm-1, E/D = 0.008 and F = 8.2× 10-5 for 1 and g⊥ = 2.580, g∥ = 2.580, D = +55.4 cm-1, and E/D = 0.000 for 2.
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Affiliation(s)
- Aparup Paul
- Department of Chemistry, Vidyasagar University, Midnapore 721102, West Bengal, India.
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36
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Yao B, Singh MK, Deng YF, Wang YN, Dunbar KR, Zhang YZ. Trigonal Prismatic Cobalt(II) Single-Ion Magnets: Manipulating the Magnetic Relaxation Through Symmetry Control. Inorg Chem 2020; 59:8505-8513. [DOI: 10.1021/acs.inorgchem.0c00950] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Binling Yao
- Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen, 518055, China
| | - Mukesh Kumar Singh
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Yi-Fei Deng
- Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen, 518055, China
| | - Yi-Nuo Wang
- Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen, 518055, China
| | - Kim R. Dunbar
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Yuan-Zhu Zhang
- Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen, 518055, China
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37
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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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38
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Deng YF, Singh MK, Gan D, Xiao T, Wang Y, Liu S, Wang Z, Ouyang Z, Zhang YZ, Dunbar KR. Probing the Axial Distortion Effect on the Magnetic Anisotropy of Octahedral Co(II) Complexes. Inorg Chem 2020; 59:7622-7630. [DOI: 10.1021/acs.inorgchem.0c00531] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yi-Fei Deng
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
| | - Mukesh Kumar Singh
- Department of Chemistry, Texas A & M University, College Station, Texas 77842, United States
| | - Dexuan Gan
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
| | - Tongtong Xiao
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | - Yinuo Wang
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
| | - Shihao Liu
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
| | - Zhenxing Wang
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | - Zhongwen Ouyang
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
| | - Yuan-Zhu Zhang
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
| | - Kim R. Dunbar
- Department of Chemistry, Texas A & M University, College Station, Texas 77842, United States
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39
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Huang XC, Li JX, Chen YZ, Wang WY, Xu R, Tao JX, Shao D, Zhang YQ. Tuning Magnetic Anisotropy in a Class of Co(II) Bis(hexafluoroacetylacetonate) Complexes. Chem Asian J 2020; 15:1469-1477. [PMID: 32202396 DOI: 10.1002/asia.201901625] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 03/21/2020] [Indexed: 11/10/2022]
Abstract
Tuning the magnetic anisotropy of metal ions remains highly interesting in the design of improved single-molecule magnets (SMMs). We herein report synthetic, structural, magnetic, and computational studies of four mononuclear CoII complexes, namely [Co(hfac)2 (MeCN)2 ] (1), [Co(hfac)2 (Spy)2 ] (2), [Co(hfac)2 (MBIm)2 ] (3), and [Co(hfac)2 (DMF)2 ] (4) (MeCN=acetonitrile, hfac=hexafluoroacetylacetone, Spy=4-styrylpyridine, MbIm=5,6-dimethylbenzimidazole, DMF=N,N-dimethylformamide), with distorted octahedral geometry constructed from hexafluoroacetylacetone (hfac) and various axial ligands. By a building block approach, complexes 2-4 were synthesized by recrystallization of the starting material of 1 from various ligands containing solution. Magnetic and theoretical studies reveal that 1-4 possess large positive D values and relative small E parameters, indicating easy-plane magnetic anisotropy with significant rhombic anisotropy in 1-4. Dynamic alternative current (ac) magnetic susceptibility measurements indicate that these complexes exhibit slow magnetic relaxation under external fields, suggesting field-induced single-ion magnets (SIMs) of 1-4. These results provide a promising platform to achieve fine tuning of magnetic anisotropy through varying the axial ligands based on Co(II) bis(hexafluoroacetylacetonate) complexes.
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Affiliation(s)
- Xing-Cai Huang
- School of Chemistry and Environmental Engineering, Yancheng Teachers University, Yancheng, 224007, China
| | - Jia-Xin Li
- Jiangsu Key Lab for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing, 210023, China
| | - Yong-Zhi Chen
- School of Chemistry and Environmental Engineering, Yancheng Teachers University, Yancheng, 224007, China
| | - Wen-Yan Wang
- School of Chemistry and Environmental Engineering, Yancheng Teachers University, Yancheng, 224007, China
| | - Rui Xu
- School of Chemistry and Environmental Engineering, Yancheng Teachers University, Yancheng, 224007, China
| | - Jin-Xia Tao
- School of Chemistry and Environmental Engineering, Yancheng Teachers University, Yancheng, 224007, China
| | - Dong Shao
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Yi-Quan Zhang
- Jiangsu Key Lab for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing, 210023, China
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40
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Zhang YJ, Yin L, Li J, Hu ZB, Ouyang ZW, Song Y, Wang Z. Synthesis, crystal structures, HF-EPR, and magnetic properties of six-coordinate transition metal (Co, Ni, and Cu) compounds with a 4-amino-1,2,4-triazole Schiff-base ligand. RSC Adv 2020; 10:12833-12840. [PMID: 35492139 PMCID: PMC9051221 DOI: 10.1039/c9ra10851c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 03/10/2020] [Indexed: 12/15/2022] Open
Abstract
We have synthesized a series of transition metal compounds [M(L)2(H2O)2] (M = Co (1), Ni (2), and Cu (3)) by using the 4-amino-1,2,4-triazole Schiff-base ligand via the hydrothermal methods. They are all mononuclear compounds with the octahedral geometry. Direct-current magnetic and HF-EPR measurements were combined to reveal the negative D values (-28.78 cm-1, -10.79 cm-1) of complexes 1 and 2, showing the easy-axis magnetic anisotropies of compounds 1 and 2. Applying a dc field of 800 Oe at 2.0 K, the slow magnetic relaxation effects were observed in compound 1, which is a remarkable feature of single-ion magnets.
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Affiliation(s)
- Ya-Jie Zhang
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology Wuhan Hubei 430074 P. R. China
| | - Lei Yin
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology Wuhan Hubei 430074 P. R. China
| | - Jing Li
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology Wuhan Hubei 430074 P. R. China
| | - Zhao-Bo Hu
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 P. R. China
| | - Zhong-Wen Ouyang
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology Wuhan Hubei 430074 P. R. China
| | - You Song
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 P. R. China
| | - Zhenxing Wang
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology Wuhan Hubei 430074 P. R. China
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41
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Brachňaková B, Matejová S, Moncol J, Herchel R, Pavlik J, Moreno-Pineda E, Ruben M, Šalitroš I. Stereochemistry of coordination polyhedra vs. single ion magnetism in penta- and hexacoordinated Co(ii) complexes with tridentate rigid ligands. Dalton Trans 2020; 49:1249-1264. [PMID: 31904039 DOI: 10.1039/c9dt04592a] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A tridentate ligand L (2,6-bis(1-(3,5-di-tert-butylbenzyl)-1H-benzimidazol-2-yl)pyridine) was synthesized and used for the preparation of three pentacoordinated Co(ii) complexes of formula [Co(L)X2] (where X = NCS- for 1, X = Cl- for 2 and X = Br- for 3) and one ionic compound 4 ([Co(L)2]Br2·2CH3OH·H2O) containing a hexacoordinated Co(ii) centre. Static magnetic data were analysed with respect to the spin (1-3) or the Griffith-Figgis (4) Hamiltonian. Ab initio calculations enable us to identify the positive axial magnetic anisotropy parameter D accompanied by a significant degree of rhombicity in the reported complexes. Also, magneto-structural correlation was outlined for this class of compounds. Moreover, all four compounds exhibit slow relaxation of magnetisation at an applied static magnetic field with either both low- and high-frequency relaxation channels (3) or a single high-frequency relaxation process (1, 2 and 4). The interplay between the stereochemistry of coordination polyhedra, magnetic anisotropy and the relaxation processes was investigated and discussed in detail.
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Affiliation(s)
- Barbora Brachňaková
- Department of Inorganic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Bratislava SK-81237, Slovakia.
| | - Simona Matejová
- Department of Inorganic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Bratislava SK-81237, Slovakia.
| | - Ján Moncol
- Department of Inorganic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Bratislava SK-81237, Slovakia.
| | - Radovan Herchel
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 771 46 Olomouc, Czech Republic
| | - Ján Pavlik
- Department of Inorganic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Bratislava SK-81237, Slovakia.
| | - Eufemio Moreno-Pineda
- Institut für Nanotechnologie, Karlsruher Institut für Technologie, Postfach 3640, Karlsruhe 76021, Germany
| | - Mario Ruben
- Institut für Nanotechnologie, Karlsruher Institut für Technologie, Postfach 3640, Karlsruhe 76021, Germany and Institute de Physique et Chimie de Matériaux de Strasbourg (IPCMS), CNRS-Université de Strasbourg, 23, rue du Loess, BP 43, 67034 Strasbourg cedex 2, France
| | - Ivan Šalitroš
- Department of Inorganic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Bratislava SK-81237, Slovakia. and Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 771 46 Olomouc, Czech Republic and Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 61200 Brno, Czech Republic
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42
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Zoufalý P, Čižmár E, Kuchár J, Herchel R. The Structural and Magnetic Properties of Fe II and Co II Complexes with 2-(furan-2-yl)-5-pyridin-2-yl-1,3,4-oxadiazole. Molecules 2020; 25:molecules25020277. [PMID: 31936620 PMCID: PMC7024161 DOI: 10.3390/molecules25020277] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/06/2020] [Accepted: 01/07/2020] [Indexed: 11/16/2022] Open
Abstract
Two novel coordination compounds containing heterocyclic bidentate N,N-donor ligand 2-(furan-2-yl)-5-(pyridin-2-yl)-1,3,4-oxadiazole (fpo) were synthesized. A general formula for compounds originating from perchlorates of iron, cobalt, and fpo can be written as: [M(fpo)2(H2O)2](ClO4)2 (M = Fe(II) for (1) Co(II) for (2)). The characterization of compounds was performed by general physico-chemical methods-elemental analysis (EA), Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) in case of organics, and single crystal X-ray diffraction (sXRD). Moreover, magneto-chemical properties were studied employing measurements in static field (DC) for 1 and X-band EPR (Electron paramagnetic resonance), direct current (DC), and alternating current (AC) magnetic measurements in case of 2. The analysis of DC magnetic properties revealed a high spin arrangement in 1, significant rhombicity for both complexes, and large magnetic anisotropy in 2 (D = -21.2 cm-1). Moreover, 2 showed field-induced slow relaxation of the magnetization (Ueff = 65.3 K). EPR spectroscopy and ab initio calculations (CASSCF/NEVPT2) confirmed the presence of easy axis anisotropy and the importance of the second coordination sphere.
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Affiliation(s)
- Pavel Zoufalý
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. Listopadu 12, CZ-771 46 Olomouc, Czech Republic; (P.Z.); or
| | - Erik Čižmár
- Institute of Physics, Faculty of Science, P.J. Šafárik University in Košice, Park Angelinum 9, SK-041 54 Košice, Slovakia;
| | - Juraj Kuchár
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. Listopadu 12, CZ-771 46 Olomouc, Czech Republic; (P.Z.); or
- Department of Inorganic Chemistry, Institute of Chemistry, Faculty of Science, P.J. Šafárik University in Košice, Moyzesova 11, SK-041 54 Košice, Slovakia
| | - Radovan Herchel
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. Listopadu 12, CZ-771 46 Olomouc, Czech Republic; (P.Z.); or
- Correspondence: ; Tel.: +420-58563-4435
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43
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Saber MR, Singh MK, Dunbar KR. Geometrical control of the magnetic anisotropy in six coordinate cobalt complexes. Chem Commun (Camb) 2020; 56:8492-8495. [DOI: 10.1039/d0cc03238g] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Combined experimental and ab initio calculations attribute the suppression of quantum tunneling and zero-field SMM behavior in the trigonal prismatic [CoTppy]PF6 (2), evidenced by hysteresis up to 3 K, to the enforced rigidity and axial geometry.
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Affiliation(s)
- Mohamed R. Saber
- Department of Chemistry
- Texas A&M University
- College Station
- USA
- Chemistry Department
| | - Mukesh K. Singh
- Department of Chemistry
- Texas A&M University
- College Station
- USA
| | - Kim R. Dunbar
- Department of Chemistry
- Texas A&M University
- College Station
- USA
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44
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Guo Z, Deng YF, Zhang Y, Pikramenou Z, Zhang YZ. Two azido-bridged [2×2] cobalt(ii) grids featuring single-molecule magnet behaviour. Dalton Trans 2020; 49:9218-9222. [DOI: 10.1039/d0dt01461c] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two Co(ii) [2 × 2] grid-like clusters containing both pyridazine and azido bridges were reported to exhibit overall intramolecular ferromagnetic coupling and field-induced single-molecule magnet behavior with the effective energy barriers up to 56 K.
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Affiliation(s)
- Zhilin Guo
- Department of Chemistry
- Southern University of Science and Technology (SUSTech)
- Shenzhen
- P. R. China
- School of Chemistry
| | - Yi-Fei Deng
- Department of Chemistry
- Southern University of Science and Technology (SUSTech)
- Shenzhen
- P. R. China
| | - Yipei Zhang
- Department of Chemistry
- Southern University of Science and Technology (SUSTech)
- Shenzhen
- P. R. China
| | - Zoe Pikramenou
- School of Chemistry
- The University of Birmingham
- Edgbaston B15 2TT
- UK
| | - Yuan-Zhu Zhang
- Department of Chemistry
- Southern University of Science and Technology (SUSTech)
- Shenzhen
- P. R. China
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45
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Böhme M, Plass W. How to link theory and experiment for single-chain magnets beyond the Ising model: magnetic properties modeled from ab initio calculations of molecular fragments. Chem Sci 2019; 10:9189-9202. [PMID: 32055306 PMCID: PMC6979495 DOI: 10.1039/c9sc02735a] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 08/15/2019] [Indexed: 12/23/2022] Open
Abstract
Magnetic properties of coordination polymers like single-chain magnets (SCMs) are based on magnetic domains, which are formed due to magnetic exchange between neighboring anisotropic spin centers. However, the computational restrictions imposed by the high level of theory needed for an adequate ab initio quantum mechanical treatment on the basis of multi-reference methods for these systems limit the feasibility of such calculations to mononuclear fragments as appropriate structural cutouts for the metal centers along the chains. Hence, results from such calculations describe single-ion properties and cannot be directly correlated with experimental data representing magnetic domains. We present a theoretical approach based on n-membered Ising-spin rings with n = 3-12, which allows us to simulate magnetic domains and to derive important magnetic properties for SCM compounds. Magnetic exchange, which is not provided by calculations of mononuclear fragments, is obtained by fitting the theoretical magnetic susceptibility against experimental data. The presented approach is tested for cobalt(ii)-based SCMs with three types of repeating sequences, which differ in nuclearity and symmetry. The magnetic parameters derived using the presented approach were found to be in good agreement with the experimental data. Moreover, the energy spectra obtained for the three test cases using the presented approach are characteristic of a deviation of the individual systems from the ideal Ising behavior. An extrapolation technique towards larger systems (n > 12) is presented which can provide information on the statistical mean length of the magnetic domains in the three investigated SCM compounds.
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Affiliation(s)
- Michael Böhme
- Institut für Anorganische und Analytische Chemie , Friedrich-Schiller-Universität Jena , Humboldtstraße 8 , 07743 Jena , Germany . ; ; Tel: +49 3641 948130
| | - Winfried Plass
- Institut für Anorganische und Analytische Chemie , Friedrich-Schiller-Universität Jena , Humboldtstraße 8 , 07743 Jena , Germany . ; ; Tel: +49 3641 948130
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46
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A Series of Field-Induced Single-Ion Magnets Based on the Seven-Coordinate Co(II) Complexes with the Pentadentate (N3O2) H2dapsc Ligand. MAGNETOCHEMISTRY 2019. [DOI: 10.3390/magnetochemistry5040058] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A series of five new mononuclear pentagonal bipyramidal Co(II) complexes with the equatorial 2,6-diacetylpyridine bis(semicarbazone) ligand (H2dapsc) and various axial pseudohalide ligands (SCN, SeCN, N(CN)2, C(CN)3, and N3) was prepared and structurally characterizated: [Co(H2dapsc)(SCN)2]∙0.5C2H5OH (1), [Co(H2dapsc)(SeCN)2]∙0.5C2H5OH (2), [Co(H2dapsc)(N(CN)2)2]∙2H2O (3), [Co(H2dapsc)(C(CN)3)(H2O)](NO3)∙1.16H2O (4), and {[Co(H2dapsc)(H2O)(N3)][Co(H2dapsc)(N3)2]}N3∙4H2O (5). The combined analyses of the experimental DС and AC magnetic data of the complexes (1–5) and two other earlier described those of this family [Co(H2dapsc)(H2O)2)](NO3)2∙2H2O (6) and [Co(H2dapsc)(Cl)(H2O)]Cl∙2H2O (7), their theoretical description and the ab initio CASSCF/NEVPT2 calculations reveal large easy-plane magnetic anisotropies for all complexes (D = + 35 − 40 cm‒1). All complexes under consideration demonstrate slow magnetic relaxation with dominant Raman and direct spin–phonon processes at static magnetic field and so they belong to the class of field-induced single-ion magnets (SIMs).
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47
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Azido-cobalt(II) coordination polymers exhibiting slow magnetic relaxation and metamagnetic transition. Polyhedron 2019. [DOI: 10.1016/j.poly.2019.06.034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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48
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Mondal A, Kharwar AK, Konar S. Sizeable Effect of Lattice Solvent on Field Induced Slow Magnetic Relaxation in Seven Coordinated CoII Complexes. Inorg Chem 2019; 58:10686-10693. [DOI: 10.1021/acs.inorgchem.9b00615] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Arpan Mondal
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal 462066, MP, India
| | - Ajit Kumar Kharwar
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal 462066, MP, India
| | - Sanjit Konar
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal 462066, MP, India
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49
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Diego R, Pavlov A, Darawsheh M, Aleshin D, Nehrkorn J, Nelyubina Y, Roubeau O, Novikov V, Aromí G. Coordination [Co II2] and [Co IIZn II] Helicates Showing Slow Magnetic Relaxation. Inorg Chem 2019; 58:9562-9566. [PMID: 31283191 DOI: 10.1021/acs.inorgchem.9b01334] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The slow magnetic relaxation of CoII ions in the elusive intermediate geometry between the trigonal prism and antiprism has been studied on the new [Co2L3]4+ and [CoZnL3]4+ coordination helicates [L is a bis(pyrazolylpyridine) ligand]. Solution paramagnetic 1H NMR and solid-state magnetization measurements unveil single-molecule-magnet behavior with small axial anisotropy, as predicted previously.
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Affiliation(s)
- Rosa Diego
- Departament de Química Inorgànica i Orgànica , Universitat de Barcelona , Diagonal 645 , 08028 Barcelona , Spain.,Institute of Nanoscience and Nanotechnology of the Unirvesity of Barcelona (IN2UB) , Barcelona , Spain
| | - Alexander Pavlov
- A. N. Nesmeyanov Institute of Organoelement Compounds , Russian Academy of Sciences , Vavilova strasse 28 , Moscow , Russia.,Moscow Institute of Physics and Technology , Institutskiy per. 9, Dolgoprudny, Moscow , Russia
| | - Mohanad Darawsheh
- Departament de Química Inorgànica i Orgànica , Universitat de Barcelona , Diagonal 645 , 08028 Barcelona , Spain
| | - Dmitry Aleshin
- A. N. Nesmeyanov Institute of Organoelement Compounds , Russian Academy of Sciences , Vavilova strasse 28 , Moscow , Russia.,Mendeleev University of Chemical Technology of Russia , Miusskaya sq. 9 , 125047 Moscow , Russia
| | - Joscha Nehrkorn
- Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36 , 45470 Mülheim an der Ruhr , Germany
| | - Yulia Nelyubina
- A. N. Nesmeyanov Institute of Organoelement Compounds , Russian Academy of Sciences , Vavilova strasse 28 , Moscow , Russia.,Moscow Institute of Physics and Technology , Institutskiy per. 9, Dolgoprudny, Moscow , Russia
| | - Olivier Roubeau
- Instituto de Ciencia de Materiales de Aragón (ICMA) , CSIC and Universidad de Zaragoza , 50009 Zaragoza , Spain
| | - Valentin Novikov
- A. N. Nesmeyanov Institute of Organoelement Compounds , Russian Academy of Sciences , Vavilova strasse 28 , Moscow , Russia.,Moscow Institute of Physics and Technology , Institutskiy per. 9, Dolgoprudny, Moscow , Russia
| | - Guillem Aromí
- Departament de Química Inorgànica i Orgànica , Universitat de Barcelona , Diagonal 645 , 08028 Barcelona , Spain.,Institute of Nanoscience and Nanotechnology of the Unirvesity of Barcelona (IN2UB) , Barcelona , Spain
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50
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Alexandropoulos DI, Vignesh KR, Xie H, Dunbar KR. Switching on single-molecule magnet properties of homoleptic sandwich tris(pyrazolyl)borate dysprosium(iii) cations via intermolecular dipolar coupling. Dalton Trans 2019; 48:10610-10618. [PMID: 31225555 DOI: 10.1039/c9dt00597h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Two new homoleptic DyIII compounds [Dy(TpMe2)2][DyCl3(TpMe2)]·CH2Cl2 (1) and [Dy(TpMe2)2]I (3) as well as a heteroleptic (NMe4)[DyCl3(TpMe2)] (2) (TpMe2 = tris(3,5-dimethylpyrazolyl)borate) species are reported. Magnetic studies revealed that 1 is a single-molecule magnet (SMM) with an energy barrier of Ueff = 80.7 K with τ0 = 6.2 × 10-7 s under a zero applied field. Compound 3 exhibits a Ueff of 13.5 K with τ0 = 1.6 × 10-6 s under a 0.08 T applied field. Ab initio CASSCF + RASSI-SO calculations were performed to further investigate the magnetic behavior of complexes 1-3. The results support experimental magnetic data for 1 and 3 and indicate that an intermolecular dipolar interaction of (zJ = -0.1 cm-1) is responsible for the SMM behavior of 1.
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Affiliation(s)
| | - Kuduva R Vignesh
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA.
| | - Haomiao Xie
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA.
| | - Kim R Dunbar
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA.
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