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Keisers K, Hüppe HM, Iffland-Mühlhaus L, Hoffmann A, Göbel C, Apfel UP, Weber B, Herres-Pawlis S. Interplay of Spin Crossover and Coordination-Induced Spin State Switch for Iron Bis(pyrazolyl)methanes in Solution. Inorg Chem 2020; 59:15343-15354. [PMID: 33002361 DOI: 10.1021/acs.inorgchem.0c02306] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Bis(pyrazolyl)bipyridinylmethane iron(II) complexes show a versatile spin state switching behavior in different solvents. In the solid, the magnetic properties of the compounds have been characterized by X-ray diffraction, Mößbauer spectroscopy, and SQUID magnetometry and point toward a high spin state. For nitrilic solvents, the solvation of the complexes leads to a change of the coordination environment from {N5O} to {N6} and results in a temperature-dependent SCO behavior. Thermodynamic properties of this transformation are obtained via UV/vis spectroscopy, SQUID measurements, and the Evans NMR method. Moreover, a coordination-induced spin state switch (CISSS) to low spin is observed by using methanol as solvent, triggered through a rearrangement of the coordination sphere. The same behavior can be observed by changing the stoichiometry of the ligand-to-metal ratio in MeCN, where the process is reversible. This transformation is monitored via UV/vis spectroscopy, and the resulting new bis-meridional coordination motif, first described for bis(pyrazolyl)methanes, is characterized in the solid state via X-ray diffraction, Mößbauer spectroscopy, and SQUID measurements. The sophisticated correlation of these switchable properties in dependence on different types of solvents reveals that the influence of the solvent on the coordination environment and magnetic properties should not be underestimated. Furthermore, careful investigation is necessary to differentiate between a thermally-induced spin crossover and a coordination-induced spin state switch.
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Affiliation(s)
- Kristina Keisers
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1a, 52074 Aachen, Germany
| | - Henrika M Hüppe
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1a, 52074 Aachen, Germany
| | - Linda Iffland-Mühlhaus
- Inorganic Chemistry I, Ruhr-Universität Bochum, Universitätsstraße 150, 44801 Bochum, Germany
| | - Alexander Hoffmann
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1a, 52074 Aachen, Germany
| | - Christoph Göbel
- Department of Chemistry, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Ulf-Peter Apfel
- Inorganic Chemistry I, Ruhr-Universität Bochum, Universitätsstraße 150, 44801 Bochum, Germany.,Fraunhofer UMSICHT, Osterfelder Straße 3, 46047 Oberhausen, Germany
| | - Birgit Weber
- Department of Chemistry, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany
| | - Sonja Herres-Pawlis
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1a, 52074 Aachen, Germany
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Synthesis, structures and magnetic properties of two iron(ii) tris(pyridyl)phosphine sulfide complexes. MENDELEEV COMMUNICATIONS 2018. [DOI: 10.1016/j.mencom.2018.03.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Hu X, Sun T, Zheng C. Synthesis, crystal structures and magnetic properties of two iron (II) tris(pyridyl)phosphine selenides complexes. PHOSPHORUS SULFUR 2018. [DOI: 10.1080/10426507.2017.1417295] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Xuecheng Hu
- Hubei Collaborative Innovation Center for Rare Metal Chemistry, Hubei Key Laboratory of Pollutant Analysis and Reuse Technology, Institute for Advanced Materials, Hubei Normal University, Huangshi, P. R. China
- Department of Chemistry, The School of Art and Science of Hubei Normal University, Huangshi, P. R. China
| | - Tingquan Sun
- Hubei Collaborative Innovation Center for Rare Metal Chemistry, Hubei Key Laboratory of Pollutant Analysis and Reuse Technology, Institute for Advanced Materials, Hubei Normal University, Huangshi, P. R. China
| | - Chunyang Zheng
- Hubei Collaborative Innovation Center for Rare Metal Chemistry, Hubei Key Laboratory of Pollutant Analysis and Reuse Technology, Institute for Advanced Materials, Hubei Normal University, Huangshi, P. R. China
- Department of Chemistry, The School of Art and Science of Hubei Normal University, Huangshi, P. R. China
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Zhang YZ, Gómez-Coca S, Brown AJ, Saber MR, Zhang X, Dunbar KR. Trigonal antiprismatic Co(ii) single molecule magnets with large uniaxial anisotropies: importance of Raman and tunneling mechanisms. Chem Sci 2016; 7:6519-6527. [PMID: 27928492 PMCID: PMC5125373 DOI: 10.1039/c6sc02035f] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 06/15/2016] [Indexed: 11/21/2022] Open
Abstract
A trigonal antiprismatic Co(ii) molecule exhibits counterion-dependent relaxation of the magnetization due to the importance of the Raman relaxation process.
The air-stable mononuclear Co(ii) compounds [CoII(Tpm)2][ClO4]2 (1, Tpm = tris(pyrazol-1-yl)methane), [CoII(Tpm)2][BPh4]2·2MeCN (2) with trigonal antiprismatic geometry (trigonally elongated octahedral geometry) are reported. Magnetic and theoretical studies reveal that the complexes exhibit single-molecule magnet behavior with uniaxial anisotropy and a huge energy difference between ground and first excited Karmers' doublets (∼200 cm–1). Under applied DC fields, compounds 1 and 2 exhibit frequency and temperature dependence of the imaginary susceptibility. The fit of the data to an Orbach relaxation process yields effective energy barriers of 30.6(1) and 44.7(6) cm–1 for 1 and 2, respectively, but there is no real state at that energy. The inclusion of tunneling, direct and Raman relaxation processes leads to the conclusion that the inclusion of an Orbach process is not required to provide a good fit to the data. More interestingly, a detailed study of the dependence of the relaxation time with field shows that for these Kramers' ions, tunneling is the predominant process at low temperature and that differences in the counteranion allow for a tuning of the Raman process at higher temperatures. These findings underscore the fact that large uniaxial anisotropy can be achieved in hexacoordinate Co(ii) trigonal antiprismatic complexes which is an unexplored geometry in mononuclear single molecule magnets.
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Affiliation(s)
- Yuan-Zhu Zhang
- Department of Chemistry , Texas A & M University , College Station , TX 77842-3012 , USA . ; ; Department of Chemistry , South University of Science and Technology of China , 518055 , Shenzhen , P. R. China
| | - Silvia Gómez-Coca
- Department of Chemistry , Texas A & M University , College Station , TX 77842-3012 , USA . ;
| | - Andrew J Brown
- Department of Chemistry , Texas A & M University , College Station , TX 77842-3012 , USA . ;
| | - Mohamed R Saber
- Department of Chemistry , Texas A & M University , College Station , TX 77842-3012 , USA . ; ; Department of Chemistry , Fayoum University , Fayoum 63514 , Egypt
| | - Xuan Zhang
- Department of Chemistry , Texas A & M University , College Station , TX 77842-3012 , USA . ;
| | - Kim R Dunbar
- Department of Chemistry , Texas A & M University , College Station , TX 77842-3012 , USA . ;
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Müller C, Koch A, Görls H, Krieck S, Westerhausen M. Tris(pyrazolyl)methanides of the Alkaline Earth Metals: Influence of the Substitution Pattern on Stability and Degradation. Inorg Chem 2015; 54:635-45. [DOI: 10.1021/ic5025907] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Christoph Müller
- Institute of Inorganic and
Analytical Chemistry (IAAC), Friedrich Schiller University Jena, Humboldtstrasse
8, 07743 Jena, Germany
| | - Alexander Koch
- Institute of Inorganic and
Analytical Chemistry (IAAC), Friedrich Schiller University Jena, Humboldtstrasse
8, 07743 Jena, Germany
| | - Helmar Görls
- Institute of Inorganic and
Analytical Chemistry (IAAC), Friedrich Schiller University Jena, Humboldtstrasse
8, 07743 Jena, Germany
| | - Sven Krieck
- Institute of Inorganic and
Analytical Chemistry (IAAC), Friedrich Schiller University Jena, Humboldtstrasse
8, 07743 Jena, Germany
| | - Matthias Westerhausen
- Institute of Inorganic and
Analytical Chemistry (IAAC), Friedrich Schiller University Jena, Humboldtstrasse
8, 07743 Jena, Germany
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Lavrenova LG, Shakirova OG. Spin Crossover and Thermochromism of Iron(II) Coordination Compounds with 1,2,4-Triazoles and Tris(pyrazol-1-yl)methanes. Eur J Inorg Chem 2012. [DOI: 10.1002/ejic.201200980] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Swart M, Güell M, Solà M. A multi-scale approach to spin crossover in Fe(ii) compounds. Phys Chem Chem Phys 2011; 13:10449-56. [DOI: 10.1039/c1cp20646j] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Güell M, Solà M, Swart M. Spin-state splittings of iron(II) complexes with trispyrazolyl ligands. Polyhedron 2010. [DOI: 10.1016/j.poly.2009.06.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Reger DL, Elgin JD, Foley EA, Smith MD, Grandjean F, Long GJ. Structural, Magnetic, and Mössbauer Spectral Study of the Electronic Spin-State Transition in [Fe{HC(3-Mepz)2(5-Mepz)}2](BF4)2. Inorg Chem 2009; 48:9393-401. [DOI: 10.1021/ic901259e] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Daniel L. Reger
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - J. Derek Elgin
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
- Department of Chemistry and Physics, Coastal Carolina University, Conway, South Carolina 29528
| | - Elizabeth A. Foley
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - Mark D. Smith
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - Fernande Grandjean
- Department of Physics, B5, University of Liège, B-4000 Sart-Tilman, Belgium
| | - Gary J. Long
- Department of Chemistry, Missouri University of Science and Technology, University of Missouri, Rolla, Missouri 65409-0010
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Xia H, Liu Y. Di-μ-chlorido-bis-{bis-[3,5-dimethyl-pyrazol-1-yl-κN)methane]iron(II)} bis-[tetra-chloridoferrate(III)]. Acta Crystallogr Sect E Struct Rep Online 2008; 64:m1504. [PMID: 21581124 PMCID: PMC2959963 DOI: 10.1107/s1600536808035253] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2008] [Accepted: 10/28/2008] [Indexed: 11/12/2022]
Abstract
In the title complex, [Fe2Cl2(C11H16N4)4][FeCl4]2, the asymmetric unit is composed of one and a half units of [Fe(bdmpm)2Cl]2(FeCl4)2(bdmpm = bis(bis(3,5-dimethylpyrazol-1-yl)methane). The three independent FeII atom have a distorted octahedral coordination geometry comprising two bridging chloride anions and four N atoms from two bis(3,5-dimethylpyrazol-1-yl)methane ligands. The FeIII atom has a tetrahedral coordination geometry comprising four chloride anions.
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Affiliation(s)
- Hongying Xia
- College of Chemistry and Chemical Engineering, Jiangxi Science and Technology Normal University, Nanchang 330013, People's Republic of China
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Abibat Salaudeen A, Kilner CA, Halcrow MA. Mononuclear and dinuclear iron thiocyanate and selenocyanate complexes of tris-pyrazolylmethane ligands. Polyhedron 2008. [DOI: 10.1016/j.poly.2008.05.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Halcrow MA. The spin-states and spin-transitions of mononuclear iron(II) complexes of nitrogen-donor ligands. Polyhedron 2007. [DOI: 10.1016/j.poly.2007.03.033] [Citation(s) in RCA: 270] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Moubaraki B, Leita BA, Halder GJ, Batten SR, Jensen P, Smith JP, Cashion JD, Kepert CJ, Létard JF, Murray KS. Structure, magnetism and photomagnetism of mixed-ligand tris(pyrazolyl)methane iron(ii) spin crossover compounds. Dalton Trans 2007:4413-26. [PMID: 17909653 DOI: 10.1039/b708773j] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A range of bis-facial tridentate chelate complexes of type [Fe((R-pz)(3)CH)((3,5-Me(2)pz)(3)CH)](BF(4))(2) has been characterised that contain two different tris-pyrazolylmethane ligands, with variations in R being H (complex crystallised as polymorphs and ) and 4-Me (), as well as R = H with a CH(2)OH arm off the methane carbon (). A tris(pyridyl)methane analogue is also described (). The tris(3,5-dimethylpyrazolyl)methane co-ligand (3,5-Me(2)pz), and the BF(4)(-) counterion, are constant throughout. The spin-crossover properties of these Fe(ii) d(6) compounds have been probed in detail by variable temperature magnetic, Mössbauer spectral and crystallographic methods. The effects of distortions from octahedral symmetry around the Fe(ii) centres, of crystal solvate molecules (1.5 MeCN in and 2 MeCN in ) and of supramolecular/crystal packing, are discussed. In the case of , subtle twisting of pyrazole rings occurs, as a function of temperature, that has a greater effect upon the relative positions of the Fe(ii) chelate molecules in polymorph than in polymorph ; this is thought to drive the cooperativity differences observed in the magnetism of the polymorphs. Comparisons are also made between to and their homoleptic, parent [Fe(L)(2)] (2+) materials. The complexes were screened for the LIESST (light induced excited spin state trapping) effect by measurements of diffuse absorption spectra on the surface of powder samples, at different temperatures. One example, , showed a 2-step thermal spin crossover transition and it was probed in detail for its photomagnetic features. The T(LIESST) and T(1/2) values for did not obey an empirical relationship, T(LIESST) = 150 - 0.3T(1/2) followed by many Fe(ii)(N-donor)(6) crossover compounds of the bis-tridentate (meridional) type, and possible reasons for this are discussed.
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Affiliation(s)
- Boujemaa Moubaraki
- School of Chemistry, Building 23, Monash University, Clayton, Victoria 3800, Australia
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