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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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Zeng M, Ruan Z, Wu S, Tong M. Field-Induced Slow Magnetic Relaxation in Mononuclear Cobalt(II) Complexes Decorated by Macrocyclic Pentaaza Ligands. Molecules 2024; 29:2810. [PMID: 38930875 PMCID: PMC11206533 DOI: 10.3390/molecules29122810] [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: 05/08/2024] [Revised: 06/04/2024] [Accepted: 06/08/2024] [Indexed: 06/28/2024] Open
Abstract
Two cobalt(II) complexes [CoL1](OTf)2 (1, L1 = 6,6''-di(anilino)-4'-phenyl-2,2':6',2''-terpyridine) and [CoL2](OTf)2·MeOH (2, L2 = 6,6''-di(N,N-dimethylamino)-4'-phenyl-2,2':6',2''-terpyridine) were synthesized and characterized. Crystal structure analyses showed that the spin carries were coordinated by five N atoms from the neutral pentaaza ligands, forming distorted trigonal bipyramidal coordination environments. Ab initio calculations revealed large easy-axial anisotropy in complexes 1 and 2. Magnetic measurements suggest that complexes 1 and 2 are field-induced single-molecule magnets, whose relaxations are mainly predominated by Raman and direct processes.
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Affiliation(s)
| | | | - Siguo Wu
- Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry, Sun Yat-Sen University, Guangzhou 510006, China; (M.Z.); (Z.R.); (M.T.)
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3
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Zhang P, Tian YC, Wang Z, Lee WZ, Ye S. Magneto-Structural Correlation of Five-Coordinate Trigonal Bipyramidal High Spin Cobalt(II) Complexes. Chemistry 2024; 30:e202400336. [PMID: 38438303 DOI: 10.1002/chem.202400336] [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: 01/26/2024] [Revised: 03/01/2024] [Accepted: 03/04/2024] [Indexed: 03/06/2024]
Abstract
Here, we combined magnetometry, multi-frequency electronic paramagnetic resonance, and wave function based ab initio calculations to investigate magnetic properties of two high spin Co(II) complexes Co(BDPRP) (BDPRP=2,6-bis((2-(S)-di(4-R)phenylhydroxylmethyl-1-pyrrolidi-nyl)methyl)pyridine, R=H for 8; R=tBu for 9). Complexes 8 and 9 featuring effective D3h symmetry were found to possess D=24.0 and 32.0 cm-1, respectively, in their S=3/2 ground states of1 e ' ' d x z / y z 4 1 e ' d x y / x 2 - y 2 2 1 a 1 ' d z 2 1 ${{\left(1{{\rm e}}^{{\rm { {^\prime}}}{\rm { {^\prime}}}}\right({d}_{xz/yz}\left)\right)}^{4}{\left(1{{\rm e}}^{{\rm { {^\prime}}}}\right({d}_{{xy/{x}^{2}-y}^{2}}\left)\right)}^{2}{\left(1{{\rm a}}_{1}^{{\rm { {^\prime}}}}\right({d}_{{z}^{2}}\left)\right)}^{1}}$ . Ligand field analyses revealed that the low-lying d-d excited states make either positive or vanishing contributions to D. Hence, total positive D values were measured for 8 and 9, as well as related D3h high spin Co(II) complexes. In contrast, negative D values are usually observed for C3v congeners. In-depth analyses suggested that lowering symmetry from D3h to C3v induces orbital mixing between1 e d x z / y z ${1{\rm e}\left({d}_{xz/yz}\right)}$ and2 e d x y / x 2 - y 2 ${2{\rm e}\left({d}_{{xy/{x}^{2}-y}^{2}}\right)}$ and admixes excited state4 A 2 1 e → 2 e ${{}^{4}{{\rm A}}_{2}\left(1e\to 2e\right)}$ into the ground state. Both factors turn the total D value progressively negative with the increasing distance (δ) of the Co(II) center out of the equatorial plane. Therefore, δ determines the sign and magnitude of final D values of five-coordinate trigonal bipyramidal S=3/2 Co(II) complexes as measured for a series of such species with varying δ.
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Affiliation(s)
- Peng Zhang
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Yao-Cheng Tian
- Department of Chemistry, National Taiwan Normal University, Taipei, 11677, Taiwan
| | - Zhenxing Wang
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Way-Zen Lee
- Department of Chemistry, National Taiwan Normal University, Taipei, 11677, Taiwan
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung, 807, Taiwan
| | - Shengfa Ye
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, P. R. China
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Biswas B, Siddiqui AI, Majee MC, Saha SK, Mondal B, Saha R, Gómez García CJ. Heptanuclear Mixed-Valence Co 4IIICo 3II Molecular Wheel─A Molecular Analogue of Layered Double Hydroxides with Single-Molecule Magnet Behavior and Electrocatalytic Activity for Hydrogen Evolution Reactions. Inorg Chem 2024; 63:6161-6172. [PMID: 38526851 PMCID: PMC11005049 DOI: 10.1021/acs.inorgchem.3c04065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 01/26/2024] [Accepted: 02/26/2024] [Indexed: 03/27/2024]
Abstract
We present a bifunctional heptanuclear cobalt(II)/cobalt(III) molecular complex formulated as [Co7(μ3-OH)4(H2L1)2(HL2)2](NO3)6·6H2O (1) (where H5L1 is 2,2'-(((1E,1'E)-((2-hydroxy-5-methyl-1,3-phenylene)bis(methanylylidene))bis(azanylylidene))bis(propane-1,3-diol)) and H2L2 is 2-amino-1,3-propanediol). Compound 1 has been characterized by single-crystal X-ray diffraction analysis along with other spectral and magnetic measurements. Structural analysis indicates that 1 contains a mixed-valence Co7 cluster where a central Co(II) ion is connected to six different Co centers (four CoIII and two CoII ions) by four μ3-OH groups, giving rise to a planar heptanuclear cluster that resembles a molecular fragment of a layered double hydroxide (LDH). Two triply deprotonated (H2L1)3- ligands form the outer side of the cluster while two singly deprotonated (HL2)- ligands are located at the top and bottom of the central heptanuclear core. Variable temperature magnetic measurements indicate the presence of weak ferromagnetic CoII···CoII interactions (J = 3.53(6) cm-1) within the linear trinuclear CoII cluster. AC susceptibility measurements show that 1 is a field-induced single-molecule magnet (SMM) with τ0 = 8.2(7) × 10-7 s and Ueff = 11.3(4) K. The electrocatalytic hydrogen evolution reaction (HER) activity of 1 in homogeneous phase shows an overpotential of 455 mV, with a Faradaic efficiency of 81% and a TOF of 8.97 × 104 μmol H2 h-1 mol-1.
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Affiliation(s)
- Biplab Biswas
- Department
of Chemistry, Kazi Nazrul University, Asansol 713340, West Bengal, India
- Department
of Chemistry, Hooghly Mohsin College, Chinsurah 712101, West Bengal, India
| | | | | | - Swadhin Kumar Saha
- Department
of Chemistry, Kazi Nazrul University, Asansol 713340, West Bengal, India
| | - Biswajit Mondal
- Department
of Chemistry, IIT Gandhinagar, Palaj 382355, Gujarat, India
| | - Rajat Saha
- Department
of Chemistry, Kazi Nazrul University, Asansol 713340, West Bengal, India
- Departamento
de Química Inorgánica, Universidad
de Valencia, Burjasot, Valencia 46100, Spain
| | - Carlos J. Gómez García
- Departamento
de Química Inorgánica, Universidad
de Valencia, Burjasot, Valencia 46100, Spain
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5
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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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6
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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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7
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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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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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9
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The Role of the Bridge in Single-Ion Magnet Behaviour: Reinvestigation of Cobalt(II) Succinate and Fumarate Coordination Polymers with Nicotinamide. INORGANICS 2022. [DOI: 10.3390/inorganics10090128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Two previously synthesized cobalt(II) coordination polymers; {[Co(μ2-suc)(nia)2(H2O)2]·2H2O}n (suc = succinate(2−), nia = nicotinamide) and [Co(μ2-fum)(nia)2(H2O)2]n (fum = fumarate(2−)) were prepared and thoroughly characterized. Both complexes form 1D coordination chains by bonding of Co(nia)2(H2O)2 units through succinate or fumarate ligands while these chains are further linked through hydrogen bonds to 3D supramolecular networks. The intermolecular interactions of both complexes are quantified using Hirshfeld surface analysis and their infrared spectra, electronic spectra and static magnetic properties are confronted with DFT and state-of-the-art ab-initio calculations. Dynamic magnetic measurements show that both complexes exhibit single-ion magnet behaviour induced by a magnetic field. Since they possess very similar chemical structure, differing only in the rigidity of the bridge between the magnetic centres, this chemical feature is put into context with changes in their magnetic relaxation.
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10
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Pilichos E, Font-Bardia M, Cano J, Escuer A, Mayans J. Slow magnetic relaxation for cobalt(II) complexes in axial bipyramidal environment: an S = 1/2 spin case. Dalton Trans 2022; 51:8986-8993. [PMID: 35536562 DOI: 10.1039/d2dt00880g] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A new family of magnetically mononuclear cobalt(II) complexes with formula [{NiII(L)CoII(H2O)2(MeOH)}{NiII(L)}2](ClO4)2 where H2L1 = bis(N,N'-bis(3-methoxysalicylidene)ethylene-1,2-diamine) (1), H2L2 = bis(N,N'-bis(3-methoxysalicylidene)propane-1,2-diamine) (2) and [{CuII(L4)}2CoII](ClO4)2 (3) where H2L4 = bis(N,N'-bis(3-ethoxysalicylidene)cyclohexane-1,2-diamine) have been obtained employing non chiral or enantiomerically pure Schiff bases. The structural studies have been carried out by single crystal X-ray and powder diffraction. Dynamic magnetic studies indicate that some members of this family present field induced slow relaxation of the magnetization and its response has been compared with the magnetically diluted [Zn0.9Co0.1] complex 1D. Ultra-low frequency Raman spectroscopy has been used to relate the slow relaxation with lattice vibrations.
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Affiliation(s)
- Evangelos Pilichos
- Departament de Química Inorgànica i Orgànica, Secció Inorgànica and Institute of Nanoscience (IN2UB) and Nanotecnology, Universitat de Barcelona, Marti i Franques 1-11, Barcelona-08028, Spain.
| | - Mercè Font-Bardia
- Departament de Mineralogia, Cristal lografia i Dipòsits Minerals and Unitat de Difracció de R-X, Centre Científic i Tecnològic de la Universitat de Barcelona (CCiTUB), Universitat de Barcelona, Solé i Sabarís 1-3, 08028 Barcelona, Spain
| | - Joan Cano
- Instituto de Ciencia Molecular (ICMol), Universitat de València, 46980 Paterna, València, Spain
| | - Albert Escuer
- Departament de Química Inorgànica i Orgànica, Secció Inorgànica and Institute of Nanoscience (IN2UB) and Nanotecnology, Universitat de Barcelona, Marti i Franques 1-11, Barcelona-08028, Spain.
| | - Júlia Mayans
- Departament de Química Inorgànica i Orgànica, Secció Inorgànica and Institute of Nanoscience (IN2UB) and Nanotecnology, Universitat de Barcelona, Marti i Franques 1-11, Barcelona-08028, Spain.
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11
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Liu M, Yang Y, Jing R, Zheng S, Yuan A, Wang Z, Luo SC, Liu X, Cui HH, Ouyang ZW, Chen L. Slow magnetic relaxation in dinuclear Co(III)-Co(II) complexes containing a five-coordinated Co(II) centre with easy-axis anisotropy. Dalton Trans 2022; 51:8382-8389. [PMID: 35587605 DOI: 10.1039/d2dt00857b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Two air-stable Co(III)-Co(II) mixed-valence complexes of molecular formulas [CoIICoIII(L)(DMAP)3(CH3COO)]·H2O·CH3OH (1) and [CoIICoIII(L)(4-Pyrrol)3 (CH3COO)]·0.5CH2Cl2 (2) (H4L = 1,3-bis-(5-methyl pyrazole-3-carboxamide) propane; DMAP = 4-dimethylaminopyridine; and 4-Pyrrol = 4-pyrrolidinopyridine) were synthesized and characterized by single-crystal X-ray crystallography, high-field electron paramagnetic resonance (HFEPR) spectroscopy, and magnetic measurements. Both complexes possess one five-coordinated paramagnetic Co(II) ion and one six-coordinated Co(III) ion with octahedral geometry. Direct-current magnetic susceptibility and magnetization measurements show the easy-axis magnetic anisotropy that is also confirmed by low-temperature HFEPR measurements and theoretical calculations. Frequency- and temperature-dependent alternating-current magnetic susceptibility measurements reveal their field-assisted slow magnetic relaxation, which is a characteristic behavior of single-molecule magnets (SMMs), caused by the individual Co(II) ion. The effective energy barrier of complex 1 (49.2 cm-1) is significantly higher than those of the other dinuclear Co(III)-Co(II) SMMs. This work hence presents the first instance of the dinuclear Co(III)-Co(II) single-molecule magnets with a five-coordinated environment around the Co(II) ion.
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Affiliation(s)
- Mengyao Liu
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, P. R. China.
| | - Yimou Yang
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, P. R. China.
| | - Rong Jing
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, P. R. China.
| | - Shaojun Zheng
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, P. R. China.
| | - Aihua Yuan
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, P. R. China.
| | - Zhenxing Wang
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology, Wuhan 430074, P. R. China.
| | - Shu-Chang Luo
- School of Chemical Engineering, Guizhou University of Engineering Science, Bijie 551700, P. R. China.
| | - Xiangyu Liu
- State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering, National Demonstration Center for Experimental Chemistry Education, College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, P. R. China.
| | - Hui-Hui Cui
- School of Chemistry and Chemical Engineering, Nantong University, Nantong 226019, P. R. China
| | - Zhong-Wen Ouyang
- Wuhan National High Magnetic Field Center & School of Physics, Huazhong University of Science and Technology, Wuhan 430074, P. R. China.
| | - Lei Chen
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, P. R. China.
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12
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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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13
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Dakua KK, Rajak K, Mishra S. Spin–vibronic coupling in the quantum dynamics of a Fe(III) trigonal-bipyramidal complex. J Chem Phys 2022; 156:134103. [DOI: 10.1063/5.0080611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The presence of a high density of excited electronic states in the immediate vicinity of the optically bright state of a molecule paves the way for numerous photo-relaxation channels. In transition-metal complexes, the presence of heavy atoms results in a stronger spin–orbit coupling, which enables spin forbidden spin-crossover processes to compete with the spin-allowed internal conversion processes. However, no matter how effectively the states cross around the Franck–Condon region, the degree of vibronic coupling, of both relativistic and non-relativistic nature, drives the population distribution among these states. One such case is demonstrated in this work for the intermediate-spin Fe(III) trigonal-bipyramidal complex. A quantum dynamical investigation of the photo-deactivation mechanism in the Fe(III) system is presented using the multi-configurational time-dependent Hartree approach based on the vibronic Hamiltonian whose coupling terms are derived from the state-averaged complete active space self-consistent field/complete active space with second-order perturbation theory (CASPT2) calculations and spin–orbit coupling of the scalar-relativistic CASPT2 states. The results of this study show that the presence of a strong (non-relativistic) vibronic coupling between the optically bright intermediate-spin state and other low-lying states of the same spin-multiplicity overpowers the spin–orbit coupling between the intermediate-spin and high-spin states, thereby lowering the chances of spin-crossover while exhibiting ultrafast relaxation among the intermediate-spin states. In a special case, where the population transfer pathway via the non-relativistic vibronic coupling is blocked, the probability of the spin-crossover is found to increase. This suggests that a careful modification of the complex by incorporation of heavier atoms with stronger relativistic effects can enhance the spin-crossover potential of Fe(III) intermediate-spin complexes.
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Affiliation(s)
- Kishan Kumar Dakua
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Karunamoy Rajak
- Centre for Theoretical Studies, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Sabyashachi Mishra
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, India
- Centre for Computational and Data Sciences, Indian Institute of Technology Kharagpur, Kharagpur, India
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14
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Xia Z, Li Y, Ji C, Jiang Y, Ma C, Gao J, Zhang J. Slow-Relaxation Behavior of a Mononuclear Co(II) Complex Featuring Long Axial Co-O Bond. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:707. [PMID: 35215035 PMCID: PMC8875892 DOI: 10.3390/nano12040707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 02/13/2022] [Accepted: 02/18/2022] [Indexed: 02/01/2023]
Abstract
Co(II) mononuclear complex with different coordination geometry would display various of field-induced single-ion magnet (SIM) behaviors. Here, we identify a field-induced single-ion magnet in a mononuclear complex Co(H2DPA)2·H2O (H2DPA = 2,6-pyridine-dicarboxylic acid) by the hydrothermal method. The long axial Co-O coordination bond (Co1‧‧‧O3) can be formed by Co1 and O3. Therefore, Co(II) ion is six-coordinated in a distorted elongated octahedron. AC magnetization susceptibilities show that the effective energy barrier is up to 43.28 K. This is much larger than most mononuclear Co(II). The distorted elongated octahedron caused by the axial Co-O coordination bond is responsible for the high effective energy barrier. The distribution of electron density in Co1 and O3 atoms in the long axial bond would influence the magnetic relaxation process in turn. Our work deepens the relationship between the effective energy barrier and the weak change of ligand field by long axial bonds, which would facilitate constructing SIM with high energy temperature.
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Affiliation(s)
- Zhengyao Xia
- Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application, School of Physical Science and Technology, Suzhou University of Science and Technology, Suzhou 215009, China; (Z.X.); (C.J.); (C.M.)
| | - Yan Li
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China;
| | - Cheng Ji
- Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application, School of Physical Science and Technology, Suzhou University of Science and Technology, Suzhou 215009, China; (Z.X.); (C.J.); (C.M.)
| | - Yucheng Jiang
- Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application, School of Physical Science and Technology, Suzhou University of Science and Technology, Suzhou 215009, China; (Z.X.); (C.J.); (C.M.)
| | - Chunlan Ma
- Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application, School of Physical Science and Technology, Suzhou University of Science and Technology, Suzhou 215009, China; (Z.X.); (C.J.); (C.M.)
| | - Ju Gao
- Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application, School of Physical Science and Technology, Suzhou University of Science and Technology, Suzhou 215009, China; (Z.X.); (C.J.); (C.M.)
- School of Optoelect Engn, Zaozhuang University, Zaozhuang 277160, China
| | - Jinlei Zhang
- Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application, School of Physical Science and Technology, Suzhou University of Science and Technology, Suzhou 215009, China; (Z.X.); (C.J.); (C.M.)
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15
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Depenbrock F, Limpke T, Stammler A, Oldengott J, Bögge H, Glaser T. Molecular and Electronic Structures of a Series of Dinuclear CoII Complexes varied by Exogeneous Ligands: Influence of π‐Bonding on Redox Potentials. Eur J Inorg Chem 2022. [DOI: 10.1002/ejic.202100992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Felix Depenbrock
- Bielefeld University: Universitat Bielefeld Chemistry Department GERMANY
| | - Thomas Limpke
- Bielefeld University: Universitat Bielefeld Chemistry Department GERMANY
| | - Anja Stammler
- Bielefeld University: Universitat Bielefeld Chemistry Department GERMANY
| | - Jan Oldengott
- Bielefeld University: Universitat Bielefeld Chemistry Department GERMANY
| | - Hartmut Bögge
- Bielefeld University: Universitat Bielefeld Chemistry department GERMANY
| | - Thorsten Glaser
- Bielefeld University: Universitat Bielefeld Department of Chemistry Universitätsstr. 24 33615 Bielefeld GERMANY
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16
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Juráková J, Midlikova J, Hrubý J, Kliuikov A, Santana VT, Pavlik J, Moncol J, Cizmar E, Orlita M, Mohelsky I, Neugebauer P, Gentili D, Cavallini M, Salitros I. Pentacoordinate Cobalt(II) Single Ion Magnets with Pendant Alkyl Chains: Shall We Go for Chloride or Bromide? Inorg Chem Front 2022. [DOI: 10.1039/d1qi01350e] [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
Four pentacoordinate complexes 1-4 of the type [Co(L1)X2] and [Co(L2)X2] (where L1=2,6-bis(1-octyl-1H-benzimidazol-2-yl)pyridine for 1 and 2, L2=2,6-bis(1-dodecyl-1H-benzimidazol -2-yl)-pyridine for 3 and 4; X = Cl- for 1 and 3, X...
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17
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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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18
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Bamberger H, Albold U, Dubnická Midlíková J, Su CY, Deibel N, Hunger D, Hallmen PP, Neugebauer P, Beerhues J, Demeshko S, Meyer F, Sarkar B, van Slageren J. Iron(II), Cobalt(II), and Nickel(II) Complexes of Bis(sulfonamido)benzenes: Redox Properties, Large Zero-Field Splittings, and Single-Ion Magnets. Inorg Chem 2021; 60:2953-2963. [PMID: 33591172 DOI: 10.1021/acs.inorgchem.0c02949] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Metal complexes of 1,2-diamidobenzenes have been long studied because of their intriguing redox properties and electronic structures. We present here a series of such complexes with 1,2-bis(sulfonamido)benzene ligands to probe the utility of these ligands for generating a large zero-field splitting (ZFS, D) in metal complexes that possibly act as single-ion magnets. To this end, we have synthesized a series of homoleptic ate complexes of the form (X)n[M{bis(sulfonamido)benzene}2] (n equals 4 minus the oxidation state of the metal), where M (Fe/Co/Ni), X [K+/(K-18-c-6)+/(HNEt3)+, with 18-c-6 = 18-crown ether 6], and the substituents (methyl and tolyl) on the ligand [bmsab = 1,2-bis(methanesulfonamido)benzene; btsab = 1,2-bis(toluenesulfonamido)benzene] were varied to analyze their effect on the ZFS, possible single-ion-magnet properties, and redox behavior of these metal complexes. A combination of X-ray crystallography, (spectro)electrochemistry, superconducting quantum interference device magnetometry, high-frequency electron paramagnetic resonance spectroscopy, and Mössbauer spectroscopy was used to investigate the electronic/geometric structures of these complexes and the aforementioned properties. These investigations show that the cobalt(II) complexes display very high negative D values in the range of -100 to -130 cm-1, and the nickel(II) complexes display very high positive D values of 76 and 58 cm-1. In addition, the cobalt(II) complexes shows barriers of 200-260 cm-1 and slow relaxation of the magnetization in the absence of an external magnetic field, underscoring the robustness of this class of complexes. The iron(II) complex exhibits a D value of -3.29 cm-1 and can be chemically oxidized to an iron(III) complex that has D = -1.96 cm-1. These findings clearly show that bis(sulfonamido)benzenes are ideally suited to stabilize ate complexes, to generate very high ZFSs at the metal centers with single-ion-magnet properties, and to induce exclusive oxidation at the metal center (for iron) despite the presence of ligands that are potentially noninnocent. Our results therefore substantially enhance the scope for this class of redox-active ligands.
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Affiliation(s)
- Heiko Bamberger
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Uta Albold
- Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstrasse 34-36, 14195 Berlin, Germany
| | | | - Cheng-Yong Su
- Lehn Institute of Functional Materials, School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China
| | - Naina Deibel
- Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstrasse 34-36, 14195 Berlin, Germany
| | - David Hunger
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Philipp P Hallmen
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Petr Neugebauer
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany.,CEITEC BUT, Brno University of Technology, Purkyňova 123, Brno 61200, Czech Republic
| | - Julia Beerhues
- Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstrasse 34-36, 14195 Berlin, Germany.,Lehrstuhl für Anorganische Koordinationschemie, Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
| | - Serhiy Demeshko
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Franc Meyer
- Institut für Anorganische Chemie, Universität Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Biprajit Sarkar
- Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstrasse 34-36, 14195 Berlin, Germany.,Lehrstuhl für Anorganische Koordinationschemie, Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
| | - Joris van Slageren
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
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19
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Cabrosi D, Cruz C, Paredes-García V, Alborés P. Anisotropic exchange interaction and field-induced SMM behaviour in a mixed valence {CoCo} complex. Dalton Trans 2021; 50:1402-1412. [PMID: 33433551 DOI: 10.1039/d0dt03075a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We are reporting the synthesis and structural characterization of a new hexanuclear Co(ii)/Co(iii) complex starting from a versatile pivalate cobalt precursor and the racemic mixture of a chelating Schiff base type ligand. The main [CoII4CoIII2(μ3-OH)2(μ-OR)2(μ-OR')2(μ-OR'')2]6+ core is unprecedented and exhibits an inversion center that affords only two unique Co(ii) sites. We performed DC and AC magnetic measurements and analysed them in terms of the anisotropic exchange of ground Kramers doublets at each Co(ii) site due to their unquenched angular orbital contribution to the magnetic moment. Quantum computations support the experimental data treatment. The interplay of dominant antiferromagnetic exchange, inversion symmetry and a non-collinear main quantization axis affords an exchange energy spectrum with mostly non-magnetic states. Nevertheless, field induced SMM behaviour is observed at 1500 Oe and below 3 K which might be explained by the relaxation of the first excited magnetic state (which is populated enough) through the next closest excited state. The Orbach and/or Raman mechanism could be operative from the experimental and quantum computed results.
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Affiliation(s)
- Daiana Cabrosi
- Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE (CONICET), Facultad de Ciencias Exactas y Naturales Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina.
| | - Carlos Cruz
- Departamento de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Avenida República 275, Santiago de Chile, Chile and Centro para el Desarrollo de la Nanociencia y Nanotecnología, CEDENNA, Santiago, Chile
| | - Verónica Paredes-García
- Departamento de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Avenida República 275, Santiago de Chile, Chile and Centro para el Desarrollo de la Nanociencia y Nanotecnología, CEDENNA, Santiago, Chile
| | - Pablo Alborés
- Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE (CONICET), Facultad de Ciencias Exactas y Naturales Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina.
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20
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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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21
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Kumar P, SantaLucia DJ, Kaniewska-Laskowska K, Lindeman SV, Ozarowski A, Krzystek J, Ozerov M, Telser J, Berry JF, Fiedler AT. Probing the Magnetic Anisotropy of Co(II) Complexes Featuring Redox-Active Ligands. Inorg Chem 2020; 59:16178-16193. [DOI: 10.1021/acs.inorgchem.0c01812] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Praveen Kumar
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
| | - Daniel J. SantaLucia
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Kinga Kaniewska-Laskowska
- Department of Inorganic Chemistry, Faculty of Chemistry, Gdańsk University of Technology, Gdańsk PL-80-233, Poland
| | - Sergey V. Lindeman
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - J. Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Mykhaylo Ozerov
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Joshua Telser
- Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605, United States
| | - John F. Berry
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Adam T. Fiedler
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
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22
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Das C, Rasamsetty A, Tripathi S, Shanmugam M. Magnetization relaxation dynamics of a rare coordinatively unsaturated Co(II) complex: experimental and theoretical insights. Chem Commun (Camb) 2020; 56:13397-13400. [PMID: 33035279 DOI: 10.1039/d0cc05963c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A robust and unusual three coordinate Co(ii) complex [Li(DME)3][Co(L)3] (1, where L = Lithium (2,6-diisopropylphenyl) amide and DME = Dimethoxyethane) shows easy plane magnetic anisotropy (D) which is validated by variable temperature X-band EPR studies. 1 also registered with the largest anisotropic barrier (51.1 K, τ0 = 1.98 × 10-8 s; Hdc ≠ 0) to the magnetization reversal among the three coordinate Co(ii) complexes. The role of its geometry on the SH parameters and the experimental observations are rationalized by theoretical calculations including the origin of magnetic anisotropy.
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Affiliation(s)
- Chinmoy Das
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, Maharashtra, India. and Current address: AIST-Kyoto University Chemical Energy Materials Open Innovation Laboratory (ChEM-OIL), National Institute of Advanced Industrial Science and Technology (AIST), Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501, Japan
| | - Amaleswari Rasamsetty
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, Maharashtra, India.
| | - Shalini Tripathi
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, Maharashtra, India.
| | - Maheswaran Shanmugam
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, Maharashtra, India.
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23
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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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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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25
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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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Zenno H, Akiyoshi R, Nakamura M, Morgan GG, Hayami S. Orbital Angular Momentum Crossover in 1-D High Spin Cobalt(II) Complex. CHEM LETT 2020. [DOI: 10.1246/cl.200395] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Hikaru Zenno
- Department of Chemistry, Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan
| | - Ryohei Akiyoshi
- Department of Chemistry, Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan
| | - Masaaki Nakamura
- Department of Chemistry, Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan
| | - Grace G. Morgan
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
| | - Shinya Hayami
- Department of Chemistry, Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan
- Institute of Industrial Nanomaterials (IINa), Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan
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Cui H, Sun T, Wang M, Chen L, Tang Y. Bulky anion supported a five-coordinate spin-crossover cobalt(II) complex with slow magnetic relaxation. J SOLID STATE CHEM 2020. [DOI: 10.1016/j.jssc.2020.121535] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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28
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Hrubý J, Dvořák D, Squillantini L, Mannini M, van Slageren J, Herchel R, Nemec I, Neugebauer P. Co(II)-Based single-ion magnets with 1,1'-ferrocenediyl-bis(diphenylphosphine) metalloligands. Dalton Trans 2020; 49:11697-11707. [PMID: 32789384 DOI: 10.1039/d0dt01512a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Herein, we report on investigations of magnetic and spectroscopic properties of three heterobimetallic Fe(ii)-Co(ii) coordination compounds based on the tetracoordinate {CoP2X2} core encapsulated by dppf metalloligand, where X = Cl (1), Br (2), I (3), dppf = 1,1'-ferrocenediyl -bis(diphenylphosphine). The analysis of static magnetic data has revealed the presence of axial magnetic anisotropy in compounds (1) and (2) and this was further confirmed by high-frequency electron spin resonance (HF-ESR) spectroscopy. Dynamic magnetic data confirmed that (1) and (2) behave as field-induced Single-Ion Magnets (SIMs). Together with bulk studies, we have also tested the possibility of depositing (2) as thick films on Au(111), glass, and polymeric acetate by drop-casting as well as thermal sublimation, a key aspect for the development of future devices embedding these magnetic objects.
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Affiliation(s)
- J Hrubý
- Central European Institute of Technology, CEITEC BUT, Purkyňova 656/123, 61200 Brno, Czech Republic.
| | - D Dvořák
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 77147 Olomouc, Czech Republic
| | - L Squillantini
- Department of Chemistry "Ugo Schiff", University of Florence and INSTM Research Unit of Florence, via Lastruccia 3-13, 50019 Sesto Fiorentino, Italy
| | - M Mannini
- Department of Chemistry "Ugo Schiff", University of Florence and INSTM Research Unit of Florence, via Lastruccia 3-13, 50019 Sesto Fiorentino, Italy
| | - J van Slageren
- Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - R Herchel
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 77147 Olomouc, Czech Republic
| | - I Nemec
- Central European Institute of Technology, CEITEC BUT, Purkyňova 656/123, 61200 Brno, Czech Republic. and Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 77147 Olomouc, Czech Republic
| | - P Neugebauer
- Central European Institute of Technology, CEITEC BUT, Purkyňova 656/123, 61200 Brno, Czech Republic.
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Huang GZ, Ruan ZY, Zheng JY, Chen YC, Wu SG, Liu JL, Tong ML. Seeking magneto-structural correlations in easily tailored pentagonal bipyramid Dy(III) single-ion magnets. Sci China Chem 2020. [DOI: 10.1007/s11426-020-9746-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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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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31
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Hu ZB, Feng X, Li J, Zhang YQ, Yin L, Wang Z, Ouyang Z, Kurmoo M, Song Y. Optimal diamagnetic dilution concentration for suppressing the dipole-dipole interaction in single-ion magnets. Dalton Trans 2020; 49:2159-2167. [PMID: 31994553 DOI: 10.1039/c9dt04403e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The effect of screening the CoII moment of monomeric [CoIIL2(H2O)] (L = 8-hydroxyquinaldine), having a trigonal bipyramid coordination, by diamagnetic Zn in CoxZn1-x solid solutions on its magnetic relaxation was explored using ac-susceptibility, high-field electron-spin-resonance measurements and CASPT2 calculations. The retention of the crystal structure for all the solid solutions was demonstrated using single crystal diffraction. The dc-magnetization and theoretical fittings of the susceptibility for Co1 and Co0.1Zn0.9 gave a large zero-field-splitting (ZFS) D of 50 ± 6 cm-1, and very weak dipole interaction between the nearest neighbors, while EPR and calculations confirmed the positive sign of the axial component (D). Consistent parameters were obtained from experiments and theory. Importantly, only field-induced relaxation was observed for the samples with less than 50% Co and a gradual change in the barrier energy to moment reversal and relaxation times was observed between 11% and 20% Co, while both were enhanced for higher dilutions. The results establish a clear barrier for extending the longevity of the magnetism for this type of single-ion species by lowering the intramolecular interactions. The results suggest that the magnetic interaction persists up to the second sphere, that is, for a dilution of 1 in 9 (11% Co). Importantly, this method is applicable to all single-ion magnet systems, that is, the optimum dilution concentration to restrain the dipole field can be given only by the single crystal structure.
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Affiliation(s)
- Zhao-Bo Hu
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
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32
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Shao F, Cahier B, Wang YT, Yang FL, Rivière E, Guillot R, Guihéry N, Tong JP, Mallah T. Magnetic Relaxation Studies on Trigonal Bipyramidal Cobalt(II) Complexes. Chem Asian J 2020; 15:391-397. [PMID: 31851414 DOI: 10.1002/asia.201901511] [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: 10/28/2019] [Revised: 12/17/2019] [Indexed: 01/05/2023]
Abstract
We report the preparation and the full characterization of a novel mononuclear trigonal bipyramidal CoII complex [Co(NS3 iPr )Br](BPh4 ) (1) with the tetradentate sulfur-containing ligand NS3 iPr (N(CH2 CH2 SCH(CH3 )2 )3 ). The comparison of its magnetic behaviour with those of two previously reported compounds [Co(NS3 iPr )Cl](BPh4 ) (2) and [Co(NS3 tBu )Br](ClO4 ) (3) (NS3 tBu =N(CH2 CH2 SC(CH3 )3 )3 ) with similar structures shows that 1 displays a single-molecule magnet behaviour with the longest magnetic relaxation time (0.051 s) at T=1.8 K, which is almost thirty times larger than that of 3 (0.0019 s) and more than three times larger than that of 2 (0.015 s), though its effective energy barrier (26 cm-1 ) is smaller. Compound 1, which contains two crystallographically independent molecules, presents smaller rhombic parameters (E=1.45 and 0.59 cm-1 ) than 2 (E=2.05 and 1.02 cm-1 ) and 3 (E=2.00 and 0.80 cm-1 ) obtained from theoretical calculations. Compounds 2 and 3 have almost the same axial (D) and rhombic (E) parameter values, but present a large difference of their effective energy barrier and magnetic relaxation which may be attributed to the larger volume of BPh4 - than ClO4 - leading to larger diamagnetic dilution (weaker magnetic dipolar interaction) for 2 than for 3. The combination of these factors leads to a much slower magnetic relaxation for 1 than for the two other compounds.
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Affiliation(s)
- Feng Shao
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405, Orsay Cedex, France.,State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P. R. China.,Present address: Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British, Columbia, V6T 1Z1, Canada
| | - Benjamin Cahier
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405, Orsay Cedex, France.,Present address: Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Yi-Ting Wang
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405, Orsay Cedex, France.,State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P. R. China
| | - Feng-Lei Yang
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405, Orsay Cedex, France.,State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P. R. China.,School of Chemistry and Material Science, Jiangsu Key Laboratory of Green Synthetic Chemistry for Functional Materials, Jiangsu Normal University, Xuzhou, Jiangsu, 221116, P. R. China
| | - Eric Rivière
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405, Orsay Cedex, France
| | - Régis Guillot
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405, Orsay Cedex, France
| | - Nathalie Guihéry
- Laboratoire de Chimie et Physique Quantiques, Université Toulouse III, Paul Sabatier, 118 route de Narbonne, 31062, Toulouse, France
| | - Jia-Ping Tong
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P. R. China.,Lab of Chemical Materials and Devices, Training Base of Army Logistics University of PLA, Xiangyang, 441000, P. R. China
| | - Talal Mallah
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405, Orsay Cedex, France
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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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Massoud SS, Perez ZE, Courson JR, Fischer RC, Mautner FA, Vančo J, Čajan M, Trávníček Z. Slow magnetic relaxation in penta-coordinate cobalt(ii) field-induced single-ion magnets (SIMs) with easy-axis magnetic anisotropy. Dalton Trans 2020; 49:11715-11726. [DOI: 10.1039/d0dt02338h] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two penta-coordinate [Co(Ln)(NCS)]ClO4 with substituted pyridyl based bispyrazolyl ligands have been structurally characterized. The complexes show an easy-axis magnetic anisotropy, large rhombicity and slow relaxation of magnetization.
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Affiliation(s)
- Salah S. Massoud
- Department of Chemistry
- University of Louisiana at Lafayette
- Lafayette
- USA
- Department of Chemistry
| | - Zoe E. Perez
- Department of Chemistry
- University of Louisiana at Lafayette
- Lafayette
- USA
| | | | - Roland C. Fischer
- Institut für Anorganische Chemie
- Technische Universität Graz
- A-8010 Graz
- Austria
| | - Franz A. Mautner
- Institut für Physikalische and Theoretische Chemie
- Technische Universität Graz
- A-8010 Graz
- Austria
| | - Ján Vančo
- Regional Centre of Advanced Technologies and Materials
- Division of Biologically Active Complexes and Molecular Magnets
- Palacký University in Olomouc
- CZ-783 71 Olomouc
- Czech Republic
| | - Michal Čajan
- Regional Centre of Advanced Technologies and Materials
- Division of Biologically Active Complexes and Molecular Magnets
- Palacký University in Olomouc
- CZ-783 71 Olomouc
- Czech Republic
| | - Zdeněk Trávníček
- Regional Centre of Advanced Technologies and Materials
- Division of Biologically Active Complexes and Molecular Magnets
- Palacký University in Olomouc
- CZ-783 71 Olomouc
- Czech Republic
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35
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Alexandropoulos DI, Vignesh KR, Xie H, Dunbar KR. Quinoxaline radical-bridged transition metal complexes with very strong antiferromagnetic coupling. Chem Commun (Camb) 2020; 56:9122-9125. [DOI: 10.1039/d0cc03713c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Synthesis, magnetic studies and, theoretical calculations of a new family of transition metal complexes bridged by a quinoxaline-based radical.
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Affiliation(s)
| | | | - Haomiao Xie
- 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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36
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Huang XC, Xu R, Chen YZ, Zhang YQ, Shao D. Two Four-Coordinate and Seven-Coordinate Co II Complexes Based on the Bidentate Ligand 1, 8-Naphthyridine Showing Slow Magnetic Relaxation Behavior. Chem Asian J 2019; 15:279-286. [PMID: 31793204 DOI: 10.1002/asia.201901395] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 11/30/2019] [Indexed: 12/11/2022]
Abstract
For a long time, the cobalt(II) complex ([Co(napy)4 ](ClO4 )2 ) (napy=1, 8-naphthyridine) has been considered as an eight-coordinate complex without any structural proof. After careful considerations, two complexes [Co(napy)2 Cl2 ] (1) and [Co(napy)4 ](ClO4 )2 (2) based on the bidentate ligand napy were synthesized and structurally characterized. X-ray single-crystal structural determination showed that the cobalt(II) center in [Co(napy)2 Cl2 ] (1) is four-coordinate with a tetrahedral geometry (Td ), while [Co(napy)4 ](ClO4 )2 (2) is seven-coordinate rather than eight-coordinate with a capped trigonal prism geometry (C2v ). Direct-current (dc) magnetic data revealed that complexes 1 and 2 possess positive zero-field splitting (ZFS) parameters of 11.08 and 25.30 cm-1 , respectively, with easy-plane magnetic anisotropy. Alternating current(ac) susceptibility measurements revealed that both complexes showed slow magnetic relaxation behaviour. Theoretical calculations demonstrated that the presence of easy-plane magnetic anisotropy (D>0) for complexes 1 and 2 is in agreement with the experimental data. Furthermore, these results pave the way to obtain four-coordinate and seven-coordinate cobalt(II) single-ion magnets (SIMs) by using a bidentate ligand.
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Affiliation(s)
- Xing-Cai Huang
- 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
| | - Yong-Zhi Chen
- School of Chemistry and Environmental Engineering, Yancheng Teachers University, Yancheng, 224007, China
| | - Yi-Quan Zhang
- Jiangsu Key Lab for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing, 210023, China
| | - Dong Shao
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China
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37
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Cui Y, Ge Y, Li Y, Tao J, Yao J, Dong Y. Single-ion magnet behavior of two pentacoordinate CoII complexes with a pincer ligand 2,6-bis(imidazo[1,5-a] pyridin-3-yl)pyridine. Struct Chem 2019. [DOI: 10.1007/s11224-019-01429-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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38
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Cui Y, Xu Y, Liu X, Li Y, Wang BL, Dong Y, Li W, Lei S. Field-Induced Single-Ion Magnetic Behavior in Two Mononuclear Cobalt(II) Complexes. Chem Asian J 2019; 14:2620-2628. [PMID: 31066179 DOI: 10.1002/asia.201900258] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 04/30/2019] [Indexed: 11/08/2022]
Abstract
The employment of a new rigid N-tridentate ligand, bis(1-chloroimidazo[1,5-a]pyridin-3-yl)pyridine (bcpp), in the construction of cobalt(II) single-ion magnets is reported. Two cobalt(II) complexes, [Co(bcpp)Cl2 ] (1) and [Co(bcpp)Br2 ] (2), have been prepared and characterized. Single-crystal XRD analyses reveal that complexes 1 and 2 are isostructural. They are pentacoordinated mononuclear cobalt(II) compounds with expected trigonal bipyramidal geometry. Both analysis of the magnetic data and ab initio calculations reveal easy-plane magnetic anisotropy (D>0) for 1 and 2. Detailed alternating current magnetic susceptibility measurements reveal the occurrence of slow magnetic relaxation behavior for the cobalt(II) centers of 1 and 2; thus indicating that both complexes are field-induced single-ion magnets.
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Affiliation(s)
- Yanfeng Cui
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, P.R. China.,Key Laboratory of Salt Lake Resources and Chemistry, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, 810008, P.R. China
| | - Yameng Xu
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, P.R. China
| | - Xin Liu
- Key Laboratory of Salt Lake Resources and Chemistry, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, 810008, P.R. China
| | - Yahong Li
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, P.R. China
| | - Bao-Lin Wang
- Jiangsu Key Laboratory for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing, 210023, P.R. China
| | - Yaping Dong
- Key Laboratory of Salt Lake Resources and Chemistry, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, 810008, P.R. China
| | - Wu Li
- Key Laboratory of Salt Lake Resources and Chemistry, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, 810008, P.R. China
| | - Shiming Lei
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA
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39
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Hay MA, McMonagle CJ, Wilson C, Probert MR, Murrie M. Trigonal to Pentagonal Bipyramidal Coordination Switching in a Co(II) Single-Ion Magnet. Inorg Chem 2019; 58:9691-9697. [DOI: 10.1021/acs.inorgchem.9b00515] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Moya A. Hay
- WestCHEM, School of Chemistry, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - Charles J. McMonagle
- Chemistry, School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom
| | - Claire Wilson
- WestCHEM, School of Chemistry, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - Michael R. Probert
- Chemistry, School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom
| | - Mark Murrie
- WestCHEM, School of Chemistry, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
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40
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Cui HH, Zhang YQ, Chen XT, Wang Z, Xue ZL. Magnetic anisotropy and slow magnetic relaxation processes of cobalt(ii)-pseudohalide complexes. Dalton Trans 2019; 48:10743-10752. [PMID: 31250855 DOI: 10.1039/c9dt00644c] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Three mononuclear six-coordinate Co(ii)-pseudohalide complexes [Co(L)X2] with two N-donor pseudohalido coligands occupying the cis-positions (X = NCS- (1), NCSe- (2) or N(CN)2- (3)), and a five-coordinate complex [Co(L)(NCO)][B(C6H5)4] (4) [L = 1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecane (12-TMC)] have been prepared and structurally characterized. Easy-plane magnetic anisotropy for 1-3 and easy-axis anisotropy for 4 were revealed via the analyses of the direct-current magnetic data, high-frequency and -field EPR (HFEPR) spectra and ab initio theoretical calculations. They display slow magnetic relaxations under an external applied dc field. Typically, two slow relaxation processes were found in 1 and 2 while only one relaxation process occurs in 3 and 4. The Raman-like mechanism is found to be dominant in the studied temperature range in 1. For 2-4, the Raman process is dominant in the low temperature region, while the Orbach mechanism dominates in the high temperature range.
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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.
| | - 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, 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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41
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Hay MA, Sarkar A, Craig GA, Bhaskaran L, Nehrkorn J, Ozerov M, Marriott KER, Wilson C, Rajaraman G, Hill S, Murrie M. In-depth investigation of large axial magnetic anisotropy in monometallic 3d complexes using frequency domain magnetic resonance and ab initio methods: a study of trigonal bipyramidal Co(ii). Chem Sci 2019; 10:6354-6361. [PMID: 31341591 PMCID: PMC6601423 DOI: 10.1039/c9sc00987f] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 05/19/2019] [Indexed: 11/21/2022] Open
Abstract
The magnetic properties of 3d monometallic complexes can be tuned through geometric control, owing to their synthetic accessibility and relative structural simplicity. Monodentate ligands offer great potential for fine-tuning the coordination environment to engineer both the axial and rhombic zero-field splitting (ZFS) parameters. In [CoCl3(DABCO)(HDABCO)] (1), the trigonal bipyramidal Co(ii) centre has two bulky axial ligands and three equatorial chloride ligands. An in-depth experimental and theoretical study of 1 reveals a large easy-plane magnetic anisotropy (+ve D) with a negligible rhombic zero-field splitting (E) due to the strict axial symmetry imposed by the C 3 symmetric ligand and trigonal space group. The large easy-plane magnetic anisotropy (D = +44.5 cm-1) is directly deduced using high-field EPR and frequency-domain magnetic resonance (FDMR) studies. Ab initio calculations reveal a large positive contribution to the D term arising from ground state/excited state mixing of the 4E'' states at ∼4085 cm-1 and a minor contribution from the spin-flip transition as well. The nature of the slow relaxation in 1 is elucidated through analysis of the rates of relaxation of magnetisation, taking into account Raman and direct spin-lattice relaxation processes and Quantum Tunnelling of the Magnetisation (QTM). The terms relating to the direct process and QTM were found based on the fit of the field-dependence of τ at 2 K. Subsequently, these were used as fixed parameters in the fit of the temperature-dependence of τ to obtain the Raman terms. This experimental-theoretical investigation provides further insight into the power of FDMR and ab initio methods for the thorough investigation of magnetic anisotropy. Thus, these results contribute to design criteria for high magnetic anisotropy systems.
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Affiliation(s)
- Moya A Hay
- WestCHEM , School of Chemistry , University of Glasgow , University Avenue , Glasgow , G12 8QQ , UK .
| | - Arup Sarkar
- Department of Chemistry , Institute of Technology Bombay , Powai , Mumbai , Maharashtra 400 076 , India .
| | - Gavin A Craig
- WestCHEM , School of Chemistry , University of Glasgow , University Avenue , Glasgow , G12 8QQ , UK .
| | - Lakshmi Bhaskaran
- Department of Physics , Florida State University , Tallahassee , FL 32306 , USA .
- National High Magnetic Field Laboratory , 1800 E. Paul Dirac Drive Tallahassee , FL 32310 , USA
| | - Joscha Nehrkorn
- National High Magnetic Field Laboratory , 1800 E. Paul Dirac Drive Tallahassee , FL 32310 , USA
- Max Planck Institute for Chemical Energy Conversion , Stiftstr. 34-36 , 45470 Mülheim an der Ruhr , Germany
| | - Mykhailo Ozerov
- National High Magnetic Field Laboratory , 1800 E. Paul Dirac Drive Tallahassee , FL 32310 , USA
| | - Katie E R Marriott
- WestCHEM , School of Chemistry , University of Glasgow , University Avenue , Glasgow , G12 8QQ , UK .
| | - Claire Wilson
- WestCHEM , School of Chemistry , University of Glasgow , University Avenue , Glasgow , G12 8QQ , UK .
| | - Gopalan Rajaraman
- Department of Chemistry , Institute of Technology Bombay , Powai , Mumbai , Maharashtra 400 076 , India .
| | - Stephen Hill
- Department of Physics , Florida State University , Tallahassee , FL 32306 , USA .
- National High Magnetic Field Laboratory , 1800 E. Paul Dirac Drive Tallahassee , FL 32310 , USA
| | - Mark Murrie
- WestCHEM , School of Chemistry , University of Glasgow , University Avenue , Glasgow , G12 8QQ , UK .
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42
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Li M, Zhao Q, Gao L, Zhang J, Zhai L, Niu X, Hu T. Slow magnetic relaxation in two mononuclear trigonal antiprismatic Co(II) complexes. Polyhedron 2019. [DOI: 10.1016/j.poly.2019.03.034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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43
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Klug CM, Ozumerzifon TJ, Bhowmick I, Livesay BN, Rappé AK, Shores MP. Anionic guest-dependent slow magnetic relaxation in Co(ii) tripodal iminopyridine complexes. Dalton Trans 2019; 48:9117-9126. [PMID: 30843557 DOI: 10.1039/c9dt00739c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We report the syntheses and magnetic property characterizations of four mononuclear cobalt(ii) complex salts featuring a tripodal iminopyridine ligand with external anion receptor groups, [CoL5-ONHtBu]X2 (X = Cl (1), Br (2), I (3) and ClO4 (4)). While all four salts exhibit anion binding through pendant amide moieties, only in the case of 1 is field-induced slow relaxation of magnetisation observed, whereas in the other salts this phenomenon is absent at the limits of our instrumentation. The effect of chloride inducing a seventh Co-N interaction and concomitant structural distortion is hypothesized as the origin of the observed dynamic magnetic properties observed in 1. Ab initio computational studies carried out on a 7-coordinate Co(ii) model species survey the complex interplay of coordination number and trigonal twisting on the sign and magnitude of the axial anisotropy parameter (D), and identify structural features whose distortions can trigger large switches in the sign and magnitude of magnetic anisotropy.
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Affiliation(s)
- Christina M Klug
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA.
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44
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Deng YF, Yao B, Zhan PZ, Gan D, Zhang YZ, Dunbar KR. Synthesis and magnetic studies of pentagonal bipyramidal metal complexes of Fe, Co and Ni. Dalton Trans 2019; 48:3243-3248. [PMID: 30775732 DOI: 10.1039/c8dt05074k] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Three mononuclear metal complexes [MII(L-N3O2)(MeCN)2][BPh4]2 (M = Fe, 1; Co, 2; Ni, 3) were isolated and structurally characterized. Magnetic studies revealed uniaxial magnetic anisotropy for 1 (D = -17.1 cm-1) and 3 (D = -14.3 cm-1) and easy-plane magnetic anisotropy for 2 (D = +36.9 cm-1). Slow magnetic relaxation was observed for complexes 1 and 2 under an applied magnetic field, both of which are dominated by a Raman process.
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Affiliation(s)
- Yi-Fei Deng
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055, P. R. China.
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45
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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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46
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Collet A, Wilson C, Murrie M. Microwave-assisted synthesis: from a mononuclear {CoII} complex to {CoII9} solvomorphs. Dalton Trans 2019; 48:854-858. [DOI: 10.1039/c8dt04557g] [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
Microwave-assisted control over nuclearity and solvomorphism.
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Affiliation(s)
- Alexandra Collet
- WestCHEM
- School of Chemistry
- University of Glasgow
- University Avenue
- Glasgow G12 8QQ
| | - Claire Wilson
- WestCHEM
- School of Chemistry
- University of Glasgow
- University Avenue
- Glasgow G12 8QQ
| | - Mark Murrie
- WestCHEM
- School of Chemistry
- University of Glasgow
- University Avenue
- Glasgow G12 8QQ
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47
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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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48
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Schulte KA, Vignesh KR, Dunbar KR. Effects of coordination sphere on unusually large zero field splitting and slow magnetic relaxation in trigonally symmetric molecules. Chem Sci 2018; 9:9018-9026. [PMID: 30647894 PMCID: PMC6301199 DOI: 10.1039/c8sc02820f] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 09/15/2018] [Indexed: 01/29/2023] Open
Abstract
Geometric control in mononuclear complexes has come to the forefront in the field of molecular magnets due to its profound effects on relaxation pathways and blocking temperature in single molecule magnets (SMMs). Herein we report the synthesis and magnetic characterization of six trigonally symmetric, divalent Fe, Co, and Ni molecules, with the rigid geometry enforced via the use of the tris-anionic, tetradentate ligand MST (N,N',N''-[2,2',2''-nitrilotris-(ethane-2,1-diyl)]tris(2,4,6-trimethylbenzenesulfonamide)). A systematic study on the effect of converting between trigonal monopyramidal complexes, (Me4N)[M(MST)], and trigonal bipyramidal complexes, (Me4N)[M(MST)(OH2)] was conducted experimentally and computationally. It was found that (Me4N)[Ni(MST)] exhibits a very large, near record zero-field splitting parameter (D) value of -434 cm-1, owing to an extremely low lying first excited state. The trigonal monopyramidal cobalt and iron complexes exhibit slow magnetic relaxation under applied fields, resulting in barriers of 45 K and 63.9 K respectively. Coordination of a single water molecule in the open axial site of the trigonal monopyramidal complexes exerts drastic dampening effects on the D value as well as slow relaxation. Computations reveal that coordination of water rotates the D zz axis away from the C 3 axis of symmetry resulting in a smaller D value. The aquo species (Me4N)[Co(MST)(OH2)] also exhibits magnetic relaxation under an applied field, but the barrier is reduced to 9.9 K. Water coordination totally quenches the magnetic behavior in the iron complex, and reduces the D value for nickel to -185 cm-1. These results showcase the drastic effect that a small change in the coordination environment can have on magnetic behavior, as well as that trigonal monopyramidal geometry can lead to near record D values.
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Affiliation(s)
- Kelsey A Schulte
- Department of Chemistry , Texas A&M University , College Station , Texas 77843 , USA .
| | - Kuduva R Vignesh
- 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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49
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Sarto C, Rouzières M, Liu JL, Bamberger H, van Slageren J, Clérac R, Alborés P. Slow magnetization dynamics in Co(ii)/Co(iii) triethanolamine/pivalate complexes. Dalton Trans 2018; 47:17055-17066. [PMID: 30462116 DOI: 10.1039/c8dt04041a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report the synthesis, structural characterization and a combined computational and experimental study of the magnetic properties of two pivalate cobalt complexes, a mononuclear Co(ii) one and a tetranuclear Co(ii)3Co(iii) mixed valence polynuclear one. The latter shows SMM behaviour revealed under an applied DC field with a thermal barrier of ca. 30 cm-1 competing with direct and Raman relaxation processes. The Orbach thermal barrier can be understood from the doublets energy ladder arising from the anisotropic exchange interaction among ground Seff = 1/2 of each Co(ii) sites. The strong local zero-field splitting of the S = 3/2 Co(ii) states affords these well isolated ground Kramers doublets. DC and AC magnetic susceptibility measurements as well as HF-EPR spectra support this interpretation. CASSCF quantum chemical computations have been also performed in order to aid the overall comprehension of the magnetic behaviour in the reported complexes.
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Affiliation(s)
- Carolina Sarto
- Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE (CONICET), Facultad de Ciencias Exactas y Naturales Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina.
| | - Mathieu Rouzières
- CNRS, CRPP, UMR 5031, 33600 Pessac, France and Univ. Bordeaux, CRPP, UMR 5031, F-33600 Pessac, France
| | - Jun-Liang Liu
- CNRS, CRPP, UMR 5031, 33600 Pessac, France and Univ. Bordeaux, CRPP, UMR 5031, F-33600 Pessac, France
| | - Heiko Bamberger
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569, Stuttgart, Germany
| | - Joris van Slageren
- Institut für Physikalische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569, Stuttgart, Germany
| | - Rodolphe Clérac
- CNRS, CRPP, UMR 5031, 33600 Pessac, France and Univ. Bordeaux, CRPP, UMR 5031, F-33600 Pessac, France
| | - Pablo Alborés
- Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE (CONICET), Facultad de Ciencias Exactas y Naturales Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina.
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50
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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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