1
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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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2
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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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3
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Bhatt G, Sharma T, Gupta SK, Meyer F, Rajaraman G, Murugavel R. Tuning Magnetic Anisotropy in Co(II) Tetrahedral Carbazole-Modified Phosphine Oxide Single-Ion Magnets: Importance of Structural Distortion versus Heavy-Ion Effect. Inorg Chem 2023; 62:18915-18925. [PMID: 37947449 DOI: 10.1021/acs.inorgchem.3c02401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Three mononuclear cobalt(II) tetrahedral complexes [Co(CzPh2PO)2X2] (CzPh2PO = (9H-carbazol-9-yl)diphenylphosphine oxide and X = Cl (1), Br (2), I (3)) have been synthesized using a simple synthetic approach to examine their single-ion magnetic (SIM) behavior. A detailed study of the variation in the dynamic magnetic properties of the Co(II) ion in a tetrahedral ligand field has been carried out by the change of the halide ligand. The axial zero-field splitting parameter D was found to vary from -16.4 cm-1 in 1 to -13.8 cm-1 in 2 and +14.6 cm-1 in 3. All the new complexes exhibit field-induced SIM behavior. The results obtained from ab initio CASSF calculations match well with the experimental data, revealing how halide ions induce a change in the D value as we move from Cl- to I-. The ab initio calculations further reveal that the change in the sign of D is due to the multideterminant characteristics of the ground state wave function of 1 and 2, while single-determinant characteristics are instead observed for 3. To gain a better understanding of the relationship between the structural distortion and the sign and magnitude of D values, magnetostructural D correlations were developed using angular relationships, revealing the importance of structural distortions over the heavy halide effect in controlling the sign of D values. This study broadens the scope of employing electronically and sterically modified phosphine oxide ligands in building new types of air-stable Co(II) SIMs.
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Affiliation(s)
- Gargi Bhatt
- Department of Chemistry, Indian Institute of Technology Bombay, Powai 400076, Mumbai, India
| | - Tanu Sharma
- Department of Chemistry, Indian Institute of Technology Bombay, Powai 400076, Mumbai, India
| | - Sandeep K Gupta
- University of Göttingen, Institute of Inorganic Chemistry, Göttingen D-37077, Germany
| | - Franc Meyer
- University of Göttingen, Institute of Inorganic Chemistry, Göttingen D-37077, Germany
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Powai 400076, Mumbai, India
| | - Ramaswamy Murugavel
- Department of Chemistry, Indian Institute of Technology Bombay, Powai 400076, Mumbai, India
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4
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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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5
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Budagumpi S, Keri RS, Nagaraju D, Yhobu Z, Monica V, Geetha B, Kadu RD, Neole N. Progress in the catalytic applications of cobalt N–heterocyclic carbene complexes: Emphasis on their synthesis, structure and mechanism. MOLECULAR CATALYSIS 2023. [DOI: 10.1016/j.mcat.2022.112850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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6
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Kumar Sahu P, Kharel R, Shome S, Goswami S, Konar S. Understanding the unceasing evolution of Co(II) based single-ion magnets. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2022.214871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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7
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Milani JLS, da Mata ÁFA, Oliveira IS, Valdo AKSM, Martins FT, Rabelo R, Cangussu D, Cano J, Lloret F, Julve M, das Chagas RP. Single-molecule magnet behaviour and catalytic properties of tetrahedral Co(II) complexes bearing chloride and 1,2-disubstituted benzimidazole as ligands. Dalton Trans 2022; 51:12258-12270. [PMID: 35895288 DOI: 10.1039/d2dt01440h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Five cobalt(II) complexes of formula [CoCl2(Ln)2] [1 with L1 = 1-benzyl-2-phenyl-1H-benzimidazole, 2 with L2 = 2-(furan-2-yl)-1-(furan-2-ylmethyl)-1H-benzimidazole, 3 with L3 = 1-(4-chlorobenzyl)-2-(4-chlorophenyl)-1H-benzimidazole, 4 with L4 = 1-(2-methoxybenzyl)-2-(2-methoxyphenyl)-1H-benzimidazole and 5 with L5 = 2-(thiophen-2-yl)-1-(thiophen-2-ylmethyl)-1H-benzimidazole] have been synthesised, spectroscopically characterised and cryomagnetically investigated. The crystal structures of 1, 3, 4 and 5 have been determined by X-ray diffraction on single crystals. Each cobalt(II) ion is four-coordinate in a distorted tetrahedral environment built by two chloride anions and two benzimidazole ligands. The neutral molecules are well separated from each other, shortest intermolecular cobalt⋯cobalt distances being greater than 9.0 Å. Static (dc) magnetic susceptibility measurements in the temperature range 2.0-300 K of 1-5 reveal the occurrence of a Curie law behaviour of magnetically non-interacting spin quadruplets in the high-temperature domain with a downturn at low temperatures due to magnetic anisotropy. The values of the D and E/D parameters for these compounds vary in the ranges -8.75 to +8.96 cm-1 and 0.00140 to 0.23, respectively. Dynamic (ac) magnetic susceptibility measurements of 1-5 show slow magnetic relaxation in the lack (1) or under the presence (1-5) of applied dc magnetic fields, a feature which is typical of single-molecule magnet behaviour (SMM). The analysis of the ac data shows that a thermally activated Orbach relaxation mechanism dominates this behaviour. Complexes 1-5 also act as efficient and highly selective eco-friendly catalysts in the coupling reaction between CO2 and epoxides to produce cyclic carbonates under solvent-free conditions. Under optimized reaction conditions, different epoxides were converted to the respective cyclic carbonate, with excellent conversions, using catalyst 4.
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Affiliation(s)
- Jorge Luiz Sônego Milani
- Instituto de Química, Universidade Federal de Goiás - UFG, Goiânia, GO, Brazil. .,Departamento de Química, Universidade Federal de Juiz de Fora - UFJF, Juiz de Fora, MG, Brazil.
| | | | | | - Ana Karoline Silva Mendanha Valdo
- Instituto de Química, Universidade Federal de Goiás - UFG, Goiânia, GO, Brazil. .,Instituto Federal Goiano, IF Goiano, Iporá, GO, Brazil
| | | | - Renato Rabelo
- Universitat de València, Departament de Química Inorgánica/Instituto de Ciencia Molecular (ICMol), Paterna, València, Spain.
| | - Danielle Cangussu
- Instituto de Química, Universidade Federal de Goiás - UFG, Goiânia, GO, Brazil.
| | - Joan Cano
- Universitat de València, Departament de Química Inorgánica/Instituto de Ciencia Molecular (ICMol), Paterna, València, Spain.
| | - Francesc Lloret
- Universitat de València, Departament de Química Inorgánica/Instituto de Ciencia Molecular (ICMol), Paterna, València, Spain.
| | - Miguel Julve
- Universitat de València, Departament de Química Inorgánica/Instituto de Ciencia Molecular (ICMol), Paterna, València, Spain.
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8
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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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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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10
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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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11
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Comba P, Rajaraman G, Sarkar A, Velmurugan G. What controls the magnetic anisotropy in heptacoordinate high-spin cobalt(II) complexes? A theoretical perspective. Dalton Trans 2022; 51:5175-5183. [PMID: 35274660 DOI: 10.1039/d1dt03903b] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The magnetic anisotropy of sixteen seven-coordinate high-spin CoII complexes with O, N, Cl and I donors was investigated with state-of-the-art ab initio CASSCF/NEVPT2 calculations and compared with experimental data. Based on the nature of the equatorial and axial ligands, which were found to tune the zero-field splitting, the complexes were classified into four groups. The experimental zero-field splitting parameters D which, for the various structures are in a range of +30 to +60 cm-1, as well as the g and E values are well reproduced. The investigation of the electronic structure shows that in these pentagonal bipyramidal complexes the donors and symmetry in the equatorial plane play an important role in the values of the axial zero-field splitting parameter D, and breaking of the horizontal plane of symmetry was found to enhance the magnitude of the D value. Although negative values of D are a desired condition for SIMs, many CoII based SIMs with positive zero-field splitting are fundamentally important to understand the nature of magnetic anisotropy, and seven coordinate CoII complexes with a large overall crystal field splitting might provide a way forward in this class of molecules.
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Affiliation(s)
- Peter Comba
- Heidelberg University, Institute of Inorganic Chemistry and Interdisciplinary Center for Scientific Computing, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.
| | - Arup Sarkar
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.
| | - Gunasekaran Velmurugan
- Heidelberg University, Institute of Inorganic Chemistry and Interdisciplinary Center for Scientific Computing, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
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12
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Ferreira PS, Cerdeira AC, Cruz TFC, Bandeira NAG, Hunger D, Allgaier A, van Slageren J, Almeida M, Pereira LCJ, Gomes PT. Single-ion magnet behaviour in homoleptic Co( ii) complexes bearing 2-iminopyrrolyl ligands. Inorg Chem Front 2022. [DOI: 10.1039/d2qi00601d] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Four-coordinate distorted tetrahedral bis(2-iminopyrrolyl)cobalt(ii) complexes behave as Single-Ion Magnets (SIMs) in the absence of an external magnetic field.
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Affiliation(s)
- Patrícia S. Ferreira
- Centro de Química Estrutural, Institute of Molecular Sciences, Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa, Portugal
| | - Ana C. Cerdeira
- Centro de Ciências e Tecnologias Nucleares, Departamento de Engenharia e Ciências Nucleares, Instituto Superior Técnico, Universidade de Lisboa, 2695-066 Bobadela LRS, Portugal
| | - Tiago F. C. Cruz
- Centro de Química Estrutural, Institute of Molecular Sciences, Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa, Portugal
| | - Nuno A. G. Bandeira
- BioISI – Biosystems & Integrative Sciences Institute, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, Ed. C8, 1749-016 Lisboa, Portugal
| | - David Hunger
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, Stuttgart D-70569, Germany
| | - Alexander Allgaier
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, Stuttgart D-70569, Germany
| | - Joris van Slageren
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, Stuttgart D-70569, Germany
| | - Manuel Almeida
- Centro de Ciências e Tecnologias Nucleares, Departamento de Engenharia e Ciências Nucleares, Instituto Superior Técnico, Universidade de Lisboa, 2695-066 Bobadela LRS, Portugal
| | - Laura C. J. Pereira
- Centro de Ciências e Tecnologias Nucleares, Departamento de Engenharia e Ciências Nucleares, Instituto Superior Técnico, Universidade de Lisboa, 2695-066 Bobadela LRS, Portugal
| | - Pedro T. Gomes
- Centro de Química Estrutural, Institute of Molecular Sciences, Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa, Portugal
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13
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Ksiądzyna M, Kinzhybalo V, Bieńko A, Medycki W, Jakubas R, Rajnák C, Boca R, Ozarowski A, Ozerov M, Piecha-Bisiorek A. Symmetry-Breaking Phase Transitions, Dielectric and Magnetic properties of Pyrrolidinium-Tetrahalidocobaltates. Inorg Chem Front 2022. [DOI: 10.1039/d2qi00187j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
We report the physicochemical characteristics of novel Co-based pyrrolidinium analogs: (C4H10N)2CoCl4 (PCC) and (C4H10N)2CoBr4 (PCB). Both compounds consist of the zero-dimensional (OD) anionic network and disordered pyrolidinium cations. The structural...
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14
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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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15
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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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16
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Kharwar AK, Mondal A, Konar S. Alignment of axial anisotropy of a mononuclear hexa-coordinated Co(ii) complex in a lattice shows improved single molecule magnetic behavior over a 2D coordination polymer having a similar ligand field. Dalton Trans 2021; 50:2832-2840. [DOI: 10.1039/d0dt04065g] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The parallel orientation of the anisotropic axes minimizes the transverse component and slow down the relaxation process and results in a higher energy barrier in 0D complex as compared to 2D framework where anisotropic axes are randomly oriented.
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Affiliation(s)
- Ajit Kumar Kharwar
- Department of Chemistry
- Indian Institute of Science Education and Research Bhopal
- Bhouri
- India
| | - Arpan Mondal
- Department of Chemistry
- Indian Institute of Science Education and Research Bhopal
- Bhouri
- India
| | - Sanjit Konar
- Department of Chemistry
- Indian Institute of Science Education and Research Bhopal
- Bhouri
- India
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17
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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: 65] [Impact Index Per Article: 16.3] [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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18
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Slow Magnetic Relaxation in a One-Dimensional Coordination Polymer Constructed from Hepta-Coordinate Cobalt(II) Nodes. MAGNETOCHEMISTRY 2020. [DOI: 10.3390/magnetochemistry6040045] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A one-dimensional coordination polymer was synthesized employing hepta-coordinate CoII as nodes and dicyanamide as linkers. Detailed direct current (DC) and alternating current (AC) magnetic susceptibility measurements reveal the presence of field-induced slow magnetic relaxation behavior of the magnetically isolated seven-coordinate CoII center with an easy-plane magnetic anisotropy. Detailed ab initio calculations were performed to understand the magnetic relaxation processes. To our knowledge, the reported complex represents the first example of slow magnetic relaxation in a one-dimensional coordination polymer constructed from hepta-coordinate CoII nodes and dicyanamide linkers.
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19
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Mantanona AJ, Tolentino DR, Cay KS, Gembicky M, Jazzar R, Bertrand G, Rinehart JD. Tuning electronic structure through halide modulation of mesoionic carbene cobalt complexes. Dalton Trans 2020; 49:2426-2430. [PMID: 32048665 DOI: 10.1039/c9dt04624k] [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
The first examples of Co(ii) mesoionic carbene complexes (CoX2DippMIC2; X = Cl-, Br-, I-) demonstrate a new electronic perturbation on tetrahedral Co(ii) complexes. Using absorption spectroscopy and magnetometry, the consequences of the MIC's strong σ-donating/minimal π-accepting nature are analyzed and shown to be further tunable by the nature of the coordinated halide.
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Affiliation(s)
- Alex J Mantanona
- Department of Chemistry and Biochemistry, University of California - San Diego, La Jolla, CA 92093, USA.
| | - Daniel R Tolentino
- Department of Chemistry and Biochemistry, University of California - San Diego, La Jolla, CA 92093, USA.
| | - Kristine S Cay
- Department of Chemistry and Biochemistry, University of California - San Diego, La Jolla, CA 92093, USA.
| | - Milan Gembicky
- Department of Chemistry and Biochemistry, University of California - San Diego, La Jolla, CA 92093, USA.
| | - Rodolphe Jazzar
- Department of Chemistry and Biochemistry, University of California - San Diego, La Jolla, CA 92093, USA.
| | - Guy Bertrand
- Department of Chemistry and Biochemistry, University of California - San Diego, La Jolla, CA 92093, USA.
| | - Jeffrey D Rinehart
- Department of Chemistry and Biochemistry, University of California - San Diego, La Jolla, CA 92093, USA.
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20
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Kowalkowska-Zedler D, Dołęga A, Nedelko N, Łyszczek R, Aleshkevych P, Demchenko I, Łuczak J, Slawska-Waniewska A, Pladzyk A. Structural, magnetic and spectral properties of tetrahedral cobalt(ii) silanethiolates: a variety of structures and manifestation of field-induced slow magnetic relaxation. Dalton Trans 2020; 49:697-710. [PMID: 31848544 DOI: 10.1039/c9dt03722e] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Blue crystals of five heteroleptic cobalt(ii) silanethiolates 1-5 have been obtained by the reaction of [Co{SSi(tBuO)3}2(NH3)]2 with aminopyridines and aminomethylpyridines at an appropriate molar ratio and their structural, spectral, thermal and magnetic properties have been established and described. All complexes 1-5 contain Co(ii) ions in a tetrahedral CoN2S2 environment formed by (tBuO)3SiS- residues and pyridines and present variable structures. Complexes 1-3 are mononuclear [Co{SSi(tBuO)3}2(L1)2] (L1 = 2-aminopyridine 2AP, 3-aminopyridine 3AP, and 4-aminopyridine 4AP). The application of 3AMP and 4AMP (3-aminomethylpyridine and 4-aminomethylpyridine) allows either dinuclear complex 4 [Co{SSi(tBuO)3}2(μ-3AMP)]2 or 1D coordination polymer 5 with the formula of [Co{SSi(tBuO)3}2(μ-4AMP)]n to be obtained. The molecular structures of 1-5 were determined by single-crystal X-ray and powder diffraction, UV-vis and FTIR spectrocopy for solid samples and their thermal properties were characterized by TG-DSC and TG-FTIR methods. The dc and ac magnetic and EPR studies of polycrystalline samples have been performed. For all complexes, the obtained data show a behavior typical of paramagnetic high-spin Co(ii) ions in a tetrahedral geometry, with a considerable contribution of the ZFS effect in a low temperature range. All complexes were also probed for SIM behavior. The modeling of the magnetic and EPR data was done for samples 1, 3, 4 and 5 to estimate ZFS parameters. The obtained results imply a negative value of the axial parameter D in complex 4 and positive D values for the rest of the compounds. A comparative magneto-structural analysis of complexes 4 and 5 points to the high sensitivity of the single-ion magnetic anisotropy of tetrahedral Co(ii) complexes to subtle changes in the first and second coordination spheres of Co(ii) ions.
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Affiliation(s)
- D Kowalkowska-Zedler
- Department of Inorganic Chemistry, Faculty of Chemistry, Gdańsk University of Technology, Narutowicza Str. 11/12, 80-233 Gdańsk, Poland.
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21
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Świtlicka A, Machura B, Kruszynski R, Moliner N, Carbonell JM, Cano J, Lloret F, Julve M. Magneto-structural diversity of Co(ii) compounds with 1-benzylimidazole induced by linear pseudohalide coligands. Inorg Chem Front 2020. [DOI: 10.1039/d0qi00752h] [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
The magneto-structural diversity of 1-benzylimidazole-containing cobalt(ii) compounds with linear pseudohalide ions (NCS−, NCO−, and N3−) is explored.
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Affiliation(s)
- Anna Świtlicka
- Department of Crystallography
- Institute of Chemistry
- University of Silesia
- 40-006 Katowice
- Poland
| | - Barbara Machura
- Department of Crystallography
- Institute of Chemistry
- University of Silesia
- 40-006 Katowice
- Poland
| | - Rafał Kruszynski
- Department of X-ray Crystallography and Crystal Chemistry
- Institute of General and Ecological Chemistry
- Lodz University of Technology
- 90-924 Łodz
- Poland
| | - Nicolás Moliner
- Department of Química Inorgànica/Instituto de Ciencia Molecular (ICMol)
- Facultat de Quimica de la Universitat de València
- 46980 Paterna
- Spain
| | - José Miguel Carbonell
- Department of Química Inorgànica/Instituto de Ciencia Molecular (ICMol)
- Facultat de Quimica de la Universitat de València
- 46980 Paterna
- Spain
| | - Joan Cano
- Department of Química Inorgànica/Instituto de Ciencia Molecular (ICMol)
- Facultat de Quimica de la Universitat de València
- 46980 Paterna
- Spain
| | - Francesc Lloret
- Department of Química Inorgànica/Instituto de Ciencia Molecular (ICMol)
- Facultat de Quimica de la Universitat de València
- 46980 Paterna
- Spain
| | - Miguel Julve
- Department of Química Inorgànica/Instituto de Ciencia Molecular (ICMol)
- Facultat de Quimica de la Universitat de València
- 46980 Paterna
- Spain
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22
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Sarkar A, Tewary S, Sinkar S, Rajaraman G. Magnetic Anisotropy in Co
II
X
4
(X=O, S, Se) Single‐Ion Magnets: Role of Structural Distortions versus Heavy Atom Effect. Chem Asian J 2019; 14:4696-4704. [DOI: 10.1002/asia.201901140] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/04/2019] [Indexed: 11/10/2022]
Affiliation(s)
- Arup Sarkar
- Department of ChemistryIndian Institute of Technology Bombay Powai Mumbai 400076 India
| | - Subrata Tewary
- Department of ChemistryIndian Institute of Technology Bombay Powai Mumbai 400076 India
- Current address: RIKEN Center for Computational Science 7-1-26, Minatojima-minami-machi Chuo-ku Kobe 650-0047 Japan
| | - Shwetali Sinkar
- Department of ChemistryIndian Institute of Technology Bombay Powai Mumbai 400076 India
| | - Gopalan Rajaraman
- Department of ChemistryIndian Institute of Technology Bombay Powai Mumbai 400076 India
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23
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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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24
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Sharma DM, Punji B. Selective Synthesis of Secondary Amines from Nitriles by a User‐Friendly Cobalt Catalyst. Adv Synth Catal 2019. [DOI: 10.1002/adsc.201900586] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Dipesh M. Sharma
- Organometallic Synthesis and Catalysis Group, Chemical Engineering Division CSIR-National Chemical Laboratory (CSIR-NCL) Dr. Homi Bhabha Road Pune 411 008 India
- Academy of Scientific and Innovative Research (AcSIR) CSIR-NCL Pune 411 008 India
| | - Benudhar Punji
- Organometallic Synthesis and Catalysis Group, Chemical Engineering Division CSIR-National Chemical Laboratory (CSIR-NCL) Dr. Homi Bhabha Road Pune 411 008 India
- Academy of Scientific and Innovative Research (AcSIR) CSIR-NCL Pune 411 008 India
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25
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Yang RC, Wang DR, Liu JL, Wang YF, Lin WQ, Leng JD, Zhou AJ. Phosphine Oxide Ligand Based Tetrahedral Co II Complexes with Field-induced Slow Magnetic Relaxation Behavior Modified by Terminal Ligands. Chem Asian J 2019; 14:1467-1471. [PMID: 30865374 DOI: 10.1002/asia.201900280] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 03/12/2019] [Indexed: 11/08/2022]
Abstract
Two isostructural mononuclear CoII complexes, [Co(xantpo)(NCE)2 ] (E=S (1) and O (2); xantpo=9,9-dimethyl-4,5-bis(diphenylphosphoryl) xanthene), supported by a bidentate phosphine oxide ligand are reported. The cobalt complexes exhibit characteristic tetrahedral structures coordinated with two oxygen and two nitrogen atoms. Magnetic property measurements show their similar static magnetic behaviours but very different dynamic magnetic behaviours. Both complexes show field-induced slow magnetic relaxation behaviours, but the relaxation of 2 is much slower than that of 1. Fittings to the magnetic data and ab initio CASSCF calculations reveal significant changes in the zero field splitting (ZFS) parameters (D and E), which can be attributed to the small geometrical changes of the Co ions and the different ligand field strength of the two terminal ligands.
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Affiliation(s)
- Rui-Chong Yang
- School of Chemistry and Chemical Engineering/Institute of Clean Energy and Materials, Guangzhou University, Guangzhou Higher Education Mega Center, No. 230 Wai Huan Xi Road, Guangzhou, 510006, P. R. China
| | - Dan-Ru Wang
- School of Chemistry and Chemical Engineering/Institute of Clean Energy and Materials, Guangzhou University, Guangzhou Higher Education Mega Center, No. 230 Wai Huan Xi Road, Guangzhou, 510006, P. R. China
| | - Jun-Liang Liu
- Key Lab of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry, Sun Yat-Sen University, Guangzhou, 510275, P. R. China
| | - Yu-Fei Wang
- School of Chemistry and Chemical Engineering/Institute of Clean Energy and Materials, Guangzhou University, Guangzhou Higher Education Mega Center, No. 230 Wai Huan Xi Road, Guangzhou, 510006, P. R. China.,Analytical and Testing Center of Guangzhou University, No. 230 Wai Huan Xi Road, Guangzhou, 510006, P. R. China
| | - Wei-Quan Lin
- School of Chemistry and Chemical Engineering/Institute of Clean Energy and Materials, Guangzhou University, Guangzhou Higher Education Mega Center, No. 230 Wai Huan Xi Road, Guangzhou, 510006, P. R. China.,Analytical and Testing Center of Guangzhou University, No. 230 Wai Huan Xi Road, Guangzhou, 510006, P. R. China
| | - Ji-Dong Leng
- School of Chemistry and Chemical Engineering/Institute of Clean Energy and Materials, Guangzhou University, Guangzhou Higher Education Mega Center, No. 230 Wai Huan Xi Road, Guangzhou, 510006, P. R. China
| | - Ai-Ju Zhou
- School of Chemistry and Chemical Engineering/Institute of Clean Energy and Materials, Guangzhou University, Guangzhou Higher Education Mega Center, No. 230 Wai Huan Xi Road, Guangzhou, 510006, P. R. China
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26
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Field Induced Single Ion Magnetic Behaviour in Square-Pyramidal Cobalt(II) Complexes with Easy-Plane Magnetic Anisotropy. MAGNETOCHEMISTRY 2019. [DOI: 10.3390/magnetochemistry5010012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Two penta-coordinate CoII complexes with formulae [Co(14-TMC)Cl](BF4) (1, 14-TMC = 1,4,8,11-Tetramethyl-1,4,8,11-tetraazacyclotetradecane) and [Co(12-TBC)Cl](ClO4)·(MeCN) (2, 12-TBC = 1,4,7,10-Tetrabenzyl-1,4,7,10-tetraazacyclododecane) were synthesized and characterized. Structural analysis revealed that ligand coordinates to the CoII centre in a tetradentate fashion and the fifth position is occupied by chloride ion and the geometries around CoII centres are best described as distorted square pyramidal. Detailed magnetic measurements disclose the presence of significant easy-plane magnetic anisotropy and field induced slow magnetic relaxation behaviours of the studied complexes. More insight into the magnetic anisotropy has been given using ab initio theory calculations, which agree well with the experimental values and further confirmed the easy-plane magnetic anisotropy.
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27
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Ferentinos E, Xu M, Grigoropoulos A, Bratsos I, Raptopoulou CP, Psycharis V, Jiang SD, Kyritsis P. Field-induced slow relaxation of magnetization in the S = 3/2 octahedral complexes trans-[Co{(OPPh 2)(EPPh 2)N} 2(dmf) 2], E = S, Se: effects of Co–Se vs. Co–S coordination. Inorg Chem Front 2019. [DOI: 10.1039/c9qi00135b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Magnetometry studies on octahedral trans-[Co{(OPPh2)(EPPh2)N}2(dmf)2], E = S, Se, complexes.
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Affiliation(s)
- Eleftherios Ferentinos
- Inorganic Chemistry Laboratory
- Department of Chemistry
- National and Kapodistrian University of Athens
- GR-15771 Athens
- Greece
| | - Meixing Xu
- College of Chemistry and Molecular Engineering
- Beijing National Laboratory for Molecular Sciences
- Beijing Key Laboratory of Magnetoelectric Materials and Devices
- Peking University
- Beijing 100871
| | - Alexios Grigoropoulos
- Inorganic Chemistry Laboratory
- Department of Chemistry
- National and Kapodistrian University of Athens
- GR-15771 Athens
- Greece
| | - Ioannis Bratsos
- NCSR “Demokritos”
- Institute of Nanoscience and Nanotechnology
- Athens
- Greece
| | | | - Vassilis Psycharis
- NCSR “Demokritos”
- Institute of Nanoscience and Nanotechnology
- Athens
- Greece
| | - Shang-Da Jiang
- College of Chemistry and Molecular Engineering
- Beijing National Laboratory for Molecular Sciences
- Beijing Key Laboratory of Magnetoelectric Materials and Devices
- Peking University
- Beijing 100871
| | - Panayotis Kyritsis
- Inorganic Chemistry Laboratory
- Department of Chemistry
- National and Kapodistrian University of Athens
- GR-15771 Athens
- Greece
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28
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Shi L, Shen FX, Shao D, Zhang YQ, Wang XY. Syntheses, structures, and magnetic properties of three two-dimensional cobalt(ii) single-ion magnets with a CoIIN4X2 octahedral geometry. CrystEngComm 2019. [DOI: 10.1039/c9ce00030e] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Three two-dimensional CoII SIMs with (4,4) layer structures have been synthesized and characterized structurally and magnetically.
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Affiliation(s)
- Le Shi
- State Key Laboratory of Coordination Chemistry
- Collaborative Innovation Center of Advanced Microstructures
- School of Chemistry and Chemical Engineering
- Nanjing University
- Nanjing
| | - Fu-Xing Shen
- State Key Laboratory of Coordination Chemistry
- Collaborative Innovation Center of Advanced Microstructures
- School of Chemistry and Chemical Engineering
- Nanjing University
- Nanjing
| | - Dong Shao
- State Key Laboratory of Coordination Chemistry
- Collaborative Innovation Center of Advanced Microstructures
- School of Chemistry and Chemical Engineering
- Nanjing University
- Nanjing
| | - Yi-Quan Zhang
- Jiangsu Key Laboratory for NSLSCS
- School of Physical Science and Technology
- Nanjing Normal University
- Nanjing 210023
- China
| | - Xin-Yi Wang
- State Key Laboratory of Coordination Chemistry
- Collaborative Innovation Center of Advanced Microstructures
- School of Chemistry and Chemical Engineering
- Nanjing University
- Nanjing
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Mondal AK, Jover J, Ruiz E, Konar S. Single-ion magnetic anisotropy in a vacant octahedral Co(ii) complex. Dalton Trans 2018; 48:25-29. [PMID: 30417181 DOI: 10.1039/c8dt03862g] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The first example of a pentacoordinate CoII single-ion magnet based on a P-donor ligand with vacant octahedral coordination geometry is reported here. Thorough magnetic measurements reveal the presence of field induced slow relaxation behavior with an easy-plane magnetic anisotropy. The combined theoretical and experimental studies disclose that direct and quantum tunneling processes become dominant at low temperature to relax the magnetization; however, from the thermal dependence of relaxation time it can be observed that the optical or acoustic Raman processes become important to the overall relaxation process.
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Affiliation(s)
- Amit Kumar Mondal
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Bhopal Bypass Road, Bhauri, Bhopal-462066, India.
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Mondal AK, Mondal A, Dey B, Konar S. Influence of the Coordination Environment on Easy-Plane Magnetic Anisotropy of Pentagonal Bipyramidal Cobalt(II) Complexes. Inorg Chem 2018; 57:9999-10008. [DOI: 10.1021/acs.inorgchem.8b01162] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Amit Kumar Mondal
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal, 462066 Madhya Pradesh, India
| | - Arpan Mondal
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal, 462066 Madhya Pradesh, India
| | - Bijoy Dey
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal, 462066 Madhya Pradesh, India
| | - Sanjit Konar
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal, 462066 Madhya Pradesh, India
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Enachi A, Baabe D, Zaretzke MK, Schweyen P, Freytag M, Raeder J, Walter MD. [(NHC)CoR2]: pre-catalysts for homogeneous olefin and alkyne hydrogenation. Chem Commun (Camb) 2018; 54:13798-13801. [DOI: 10.1039/c8cc08891h] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
[(ItBu)Co(CH2SiMe3)2] serves as an efficient, homogeneous olefin hydrogenation catalyst.
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Affiliation(s)
- Andreea Enachi
- Technische Universität Braunschweig
- Institut für Anorganische und Analytische Chemie
- 38106 Braunschweig
- Germany
| | - Dirk Baabe
- Technische Universität Braunschweig
- Institut für Anorganische und Analytische Chemie
- 38106 Braunschweig
- Germany
| | - Marc-Kevin Zaretzke
- Technische Universität Braunschweig
- Institut für Anorganische und Analytische Chemie
- 38106 Braunschweig
- Germany
| | - Peter Schweyen
- Technische Universität Braunschweig
- Institut für Anorganische und Analytische Chemie
- 38106 Braunschweig
- Germany
| | - Matthias Freytag
- Technische Universität Braunschweig
- Institut für Anorganische und Analytische Chemie
- 38106 Braunschweig
- Germany
| | - Jan Raeder
- Technische Universität Braunschweig
- Institut für Anorganische und Analytische Chemie
- 38106 Braunschweig
- Germany
| | - Marc D. Walter
- Technische Universität Braunschweig
- Institut für Anorganische und Analytische Chemie
- 38106 Braunschweig
- Germany
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