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Juráková J, Santana VT, Pavlik J, Moncoľ J, Nemec I, Clemente-León M, Kuppusamy SK, Ruben M, Čižmár E, Šalitroš I. Magnetic anisotropy and slow relaxation of magnetisation in double salts containing four- and six-coordinate cobalt(II) complex ions. Dalton Trans 2024. [PMID: 39026489 DOI: 10.1039/d4dt01509f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Four novel Co(II) coordination compounds 1-4 of the general formula [Co(Ln)2][Co(NCY)4]·mCH3CN (where Ln are tridentate ligands L1 = 2,6-bis(1-hexyl-1H-benzimidazol-2-yl)pyridine for 1 and 2; L2 = 2,6-bis(1-octyl-1H-benzimidazol-2-yl)pyridine for 3; L3 = 2,6-bis(1-dodecyl-1H-benzimidazol-2-yl)pyridine for 4, Y = O for 1, 3, and 4 and Y = S for 2; m = 0 for 1 and 3, m = 0.5 for 2 and m = 2 for 4) were prepared and characterised. The molecular structures of all four compounds consist of the hexacoordinate complex cation [Co(Ln)2]2+ and tetracoordinate complex anion [Co(NCY)4]2-, with distorted octahedral and tetrahedral symmetry of coordination polyhedra, respectively. The electronic structures of all compounds feature an orbitally non-degenerate ground state well-separated from the lowest excited state, which allows the analysis of the magnetic anisotropy by the spin Hamiltonian model. ZFS parameters, derived from both CASSCF-NEVPT2 calculations and magnetic data analysis, indicate that tetrahedral anions [Co(NCY)4]2- exhibit small axial parameters |D| spanning the range of 2.2 to 7.7 cm-1, while octahedral cations [Co(Ln)2]2+ display significantly larger |D| parameters in the range of 37 to 95 cm-1. For 1-3, the Fourier-transform infrared magnetic spectroscopy (FIRMS) revealed a reasonable transmission with a magnetic absorption around the expected value for the ZFS accompanied by features allowing to identify phonon frequencies and simulate spin-phonon couplings. Dynamic magnetic investigations unveiled the field-induced slow relaxation of magnetisation, with maximal relaxation times (τ) of 92(2) μs for 2 at 2 K and BDC = 0.3 T. The temperature evolution of τ was analysed using a combination of Orbach, direct and Raman relaxations (Ueff = 8(1) K (5.6 cm-1)) or Orbach, direct and spin-phonon induced relaxations (Ueff = 10.3(9) K (7.2 cm-1)). The rest of the complexes, namely 1, 3, and 4 show field-induced slow relaxation of magnetisation with τ smaller than 16 μs.
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Affiliation(s)
- Jana Juráková
- 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 SK-81237, Slovakia.
| | - Vinicius Tadeu Santana
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 61200 Brno, Czech Republic
| | - Ján Pavlik
- Department of Inorganic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Bratislava SK-81237, Slovakia.
| | - Ján Moncoľ
- Department of Inorganic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Bratislava SK-81237, Slovakia.
| | - Ivan Nemec
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 61200 Brno, Czech Republic
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 771 46 Olomouc, Czech Republic
| | - Miguel Clemente-León
- Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, Catedrático José Beltrán 2, 46980 Paterna, Spain
| | - Senthil Kumar Kuppusamy
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Mario Ruben
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Erik Čižmár
- Institute of Physics, Faculty of Science, P.J. Šafárik University, Park Angelinum 9, 04154 Košice, Slovakia
| | - 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 SK-81237, Slovakia.
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Choroba K, Palion-Gazda J, Machura B, Bieńko A, Wojtala D, Bieńko D, Rajnák C, Boča R, Ozarowski A, Ozerov M. Large Magnetic Anisotropy in Mono- and Binuclear cobalt(II) Complexes: The Role of the Distortion of the Coordination Sphere in Validity of the Spin-Hamiltonian Formalism. Inorg Chem 2024; 63:1068-1082. [PMID: 38166196 DOI: 10.1021/acs.inorgchem.3c03405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
To get a better insight into understanding the factors affecting the enhancement of the magnetic anisotropy in single molecule (single ion) magnets, two cobalt(II) complexes based on a tridentate ligand 2,6-di(thiazol-2-yl)pyridine substituted at the 4-position with N-methyl-pyrrol-2-yl have been synthesized and studied by X-ray crystallography, AC and DC magnetic data, FIRMS and HFEPR spectra, and theoretical calculations. The change of the counteranion in starting Co(II) salts results in the formation of pentacoordinated mononuclear [Co(mpyr-dtpy)Cl2]·2MeCN (1) complex and binuclear [Co(mpyr-dtpy)2][Co(NCS)4] (2) compound. The observed marked distortion of trigonal bipyramid geometry in 1 and cationic octahedral and anionic tetrahedral units in 2 brings up a question about the validity of the spin-Hamiltonian formalism and the possibility of determining the value and sign of the zero-field splitting D parameter. Both complexes exhibit field-induced slow magnetic relaxation with two or three relaxation channels at BDC = 0.3 T. The high-frequency relaxation time in the reciprocal form τ(HF)-1 = CTn develops according to the Raman relaxation mechanism (for 2, n = 8.8) and the phonon-bottleneck-like mechanism (for 1, n = 2.3). The high-frequency relaxation time at T = 2.0 K and BDC = 0.30 T is τ(HF) = 96 and 47 μs for 1 and 2, respectively.
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Affiliation(s)
- Katarzyna Choroba
- Institute of Chemistry, Faculty of Science and Technology, University of Silesia, Szkolna St. 9, Katowice 40-006, Poland
| | - Joanna Palion-Gazda
- Institute of Chemistry, Faculty of Science and Technology, University of Silesia, Szkolna St. 9, Katowice 40-006, Poland
| | - Barbara Machura
- Institute of Chemistry, Faculty of Science and Technology, University of Silesia, Szkolna St. 9, Katowice 40-006, Poland
| | - Alina Bieńko
- Faculty of Chemistry, Joliot-Curie 14, Wroclaw 50-383, Poland
| | - Daria Wojtala
- Faculty of Chemistry, Joliot-Curie 14, Wroclaw 50-383, Poland
| | - Dariusz Bieńko
- Faculty of Chemistry, Wroclaw University of Science Technology, Wybrzeze Wyspiańskiego 27, Wroclaw 50-370, Poland
| | - Cyril Rajnák
- Faculty of Health Science and Faculty of Natural Sciences, University of SS Cyril and Methodius, Trnava SK-917 01, Slovakia
| | - Roman Boča
- Institute of Chemistry, Faculty of Science and Technology, University of Silesia, Szkolna St. 9, Katowice 40-006, Poland
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Mykhaylo Ozerov
- National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
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Macek L, Bellamy JC, Faber K, Milson CR, Landee CP, Dickie DA, Turnbull MM. Transition metal halide complexes of 4′-aminoacetophenone: Syntheses, structures, and magnetic behavior. Polyhedron 2023. [DOI: 10.1016/j.poly.2022.116214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Thierer LM, Brooks SH, Weberg AB, Cui P, Zhang S, Gau MR, Manor BC, Carroll PJ, Tomson NC. Macrocycle-Induced Modulation of Internuclear Interactions in Homobimetallic Complexes. Inorg Chem 2022; 61:6263-6280. [PMID: 35422117 PMCID: PMC9252315 DOI: 10.1021/acs.inorgchem.2c00522] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A synthetic route has been developed for a series of 3d homobimetallic complexes of Mn, Fe, Co, Ni, and Cu using three different pyridyldiimine and pyridyldialdimine macrocyclic ligands with ring sizes of 18, 20, and 22 atoms. Crystallographic analyses indicate that while the distances between the metals can be modulated by the size of the macrocycle pocket, the flexibility in the alkyl linkers used to construct the macrocycles enables the ligand to adjust the orientation of the PD(A)I fragments in response to the geometry of the [M2(μ-Cl)2]2+ core, particularly with respect to Jahn-Teller distortions. Analyses by UV-vis spectroscopy and SQUID magnetometry revealed deviations in the properties [M2(μ-Cl)2]2+-containing complexes bound by standard mononucleating ligands, highlighting the ability of macrocycles to use ring size to control the magnetic interactions of pseudo-octahedral, high-spin metal centers.
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Affiliation(s)
- Laura M. Thierer
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Sam H. Brooks
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Alexander B. Weberg
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Peng Cui
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Shaoguang Zhang
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Michael R. Gau
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Brian C. Manor
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Patrick J. Carroll
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Neil C. Tomson
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States
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Synthesis, structure and magnetic properties of binuclear 3d-metal complexes of new 3-(2-pyridyl)-6-phenyl-1,2,4-triazine derivative. Polyhedron 2021. [DOI: 10.1016/j.poly.2020.114901] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Che Hassan H, Mohd Said S, Nik Ibrahim NMJ, Megat Hasnan MMI, Mohd Noor IS, Zakaria R, Mohd Salleh MF, Md. Noor NL, Abdullah N. Ultra-high Seebeck coefficient of a thermal sensor through entropic optimisation of ligand length of Fe( ii) spin-crossover (SCO) materials. RSC Adv 2021; 11:20970-20982. [PMID: 35479345 PMCID: PMC9034036 DOI: 10.1039/d1ra01387d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 06/03/2021] [Indexed: 11/21/2022] Open
Abstract
In this work, we present a spin-crossover (SCO) complex molecular formulation [Fe(Ln)2](BF4)2 in an electrochemical single couple solution. A Seebeck voltage arises when an electrochemical single couple solution is subjected to a temperature difference, resulting in a single couple reaction at either terminal of the electrochemical cell. The ultrahigh Seebeck coefficients were obtained due to a number of molecular optimisation strategies. The [Fe(L16)2](BF4)2 complex demonstrated a maximum Seebeck coefficient of 8.67 mV K−1, achieved through a six-pronged approach to maximise entropy during the transition from low spin (LS) to high spin (HS) through: (i) a change in spin state, (ii) a change in physical liquid crystalline state, (iii) the spin Seebeck effect, (iv) the kosmotropic and chaotropic effect, (v) the fastener effect and (vi) thermal heat absorbance. A reduction of the Seebeck coefficient to 1.68 mV K−1 during the HS–LS transition at higher temperatures is related to the single spin state transition entropy change. In summary, this paper presents a systematic study to identify the contributing factors in the production of a sensor with an ultrahigh Seebeck coefficient for energy harvesting through the optimisation of its molecular entropy elements. The molecular optimisation strategies exhibit ultrahigh Seebeck coefficient through a six-pronged approach to maximise entropy during the transition from low spin (LS) to high spin (HS).![]()
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Affiliation(s)
- Hazirah Che Hassan
- Department of Electrical Engineering
- Faculty of Engineering
- University of Malaya
- 50603 Kuala Lumpur
- Malaysia
| | - Suhana Mohd Said
- Department of Electrical Engineering
- Faculty of Engineering
- University of Malaya
- 50603 Kuala Lumpur
- Malaysia
| | - Nik Muhd Jazli Nik Ibrahim
- Department of Electrical Engineering
- Faculty of Engineering
- University of Malaya
- 50603 Kuala Lumpur
- Malaysia
| | - Megat Muhammad Ikhsan Megat Hasnan
- Microelectronic and Nanotechnology – Shamsuddin Research Centre (MiNT-SRC)
- Faculty of Electrical and Electronic Engineering
- University Tun Hussein Onn
- 86400 Batu Pahat
- Malaysia
| | - Ikhwan Syafiq Mohd Noor
- Physics Division
- Centre of Foundation Studies for Agricultural Science
- University Putra Malaysia
- 43400 UPM Serdang
- Malaysia
| | - Rozalina Zakaria
- Department of Physics
- Faculty of Science
- University of Malaya
- 50603 Kuala Lumpur
- Malaysia
| | - Mohd Faiz Mohd Salleh
- Department of Electrical Engineering
- Faculty of Engineering
- University of Malaya
- 50603 Kuala Lumpur
- Malaysia
| | | | - Norbani Abdullah
- Department of Chemistry
- Faculty of Science
- University of Malaya
- 50603 Kuala Lumpur
- Malaysia
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Spin Crossover in 3D Metal Centers Binding Halide-Containing Ligands: Magnetism, Structure and Computational Studies. SUSTAINABILITY 2020. [DOI: 10.3390/su12062512] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The capability of a given substance to change its spin state by the action of a stimulus, such as a change in temperature, is by itself a very challenging property. Its interest is increased by the potential applications and the need to find sustainable functional materials. 3D transition metal complexes, mainly with octahedral geometry, display this property when coordinated to particular sets of ligands. The prediction of this behavior has been attempted by many authors. It is, however, made very difficult because spin crossover (SCO), as it is called, occurs most often in the solid state, where besides complexes, counter ions, and solvents are also present in many cases. Intermolecular interactions definitely play a major role in SCO. In this review, we decided to analyze SCO in mono- and binuclear transition metal complexes containing halogens as ligands or as substituents of the ligands. The aim was to try and find trends in the properties which might be correlated to halogen substitution patterns. Besides a revision of the properties, we analyzed structures and other information. We also tried to build a simple model to run Density Functional Theory (DFT) calculations and calculate several parameters hoping to find correlations between calculated indices and SCO data. Although there are many experimental studies and single-crystal X-ray diffraction structures, there are only few examples with the F, Cl, Br and series. When their intermolecular interactions were not very different, T1/2 (temperature with 50% high spin and 50% low spin states) usually increased with the calculated ligand field parameter (Δoct) within a given family. A way to predict SCO remains elusive.
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Coordination Polymer Based on Nickel(II) Maleate and 4′-Phenyl-2,2′:6′,2″-Terpyridine: Synthesis, Crystal Structure and Conjugated Thermolysis. J Inorg Organomet Polym Mater 2019. [DOI: 10.1007/s10904-019-01227-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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