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Gamage EH, Kamali S, Kumar GS, Clark JK, Lee Y, Abusa Y, Yox P, Ke L, Shatruk M, Kovnir K. Inducing Ferrimagnetic Exchange in 1D-FeSe 2 Chains Using Heteroleptic Amine Complexes: [Fe(en)(tren)][FeSe 2] 2. Inorg Chem 2024; 63:2443-2453. [PMID: 38252972 DOI: 10.1021/acs.inorgchem.3c03440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
[Fe(en)(tren)][FeSe2]2 (en = ethylenediamine, C2H8N2, tren = tris(2-aminoethyl)amine, C6H18N4) has been synthesized by a mixed-ligand solvothermal method. Its crystal structure contains heteroleptic [Fe(en)(tren)]2+ complexes with distorted octahedral coordination, incorporated between 1D-FeSe2 chains composed of edge-sharing FeSe4 tetrahedra. The twisted octahedral coordination environment of the Fe-amine complex leads to partial dimerization of Fe-Fe distances in the FeSe2 chains so that the FeSe4 polyhedra deviate strongly from the regular tetrahedral geometry. 57Fe Mössbauer spectroscopy reveals oxidation states of +3 for the Fechain atoms and +2 for the Fecomplex atoms. The close proximity of Fe atoms in the chains promotes ferromagnetic nearest neighbor interactions, as indicated by a positive Weiss constant, θ = +53.8(6) K, derived from the Curie-Weiss fitting. Magnetometry and heat capacity reveal two consecutive magnetic transitions below 10 K. DFT calculations suggest that the ordering observed at 4 K is due to antiferromagnetic intrachain interactions in the 1D-FeSe2 chains. The combination of two different ligands creates an asymmetric coordination environment that induces changes in the structure of the Fe-Se fragments. This synthetic strategy opens new ways to explore the effects of ligand field strength on the structure of both Fe-amine complexes and surrounding Fe-Se chains.
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Affiliation(s)
- Eranga H Gamage
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
- U.S. Department of Energy, Ames National Laboratory, Ames, Iowa 50011, United States
| | - Saeed Kamali
- Mechanical, Aerospace & Biomedical Engineering Department, University of Tennessee Space Institute, Tullahoma, Tennessee 37388, United States
- Department of Physics and Astronomy, Middle Tennessee State University, Murfreesboro, Tennessee 37132, United States
| | - Govind Sasi Kumar
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Judith K Clark
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Yongbin Lee
- U.S. Department of Energy, Ames National Laboratory, Ames, Iowa 50011, United States
| | - Yao Abusa
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Philip Yox
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
- U.S. Department of Energy, Ames National Laboratory, Ames, Iowa 50011, United States
| | - Liqin Ke
- U.S. Department of Energy, Ames National Laboratory, Ames, Iowa 50011, United States
| | - Michael Shatruk
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
- National High Magnetic Field Laboratory, 1800 E Paul Dirac Dr, Tallahassee, Florida 32310, United States
| | - Kirill Kovnir
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
- U.S. Department of Energy, Ames National Laboratory, Ames, Iowa 50011, United States
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Gamage EH, Kamali S, Clark JK, Lee Y, Yox P, Shafer P, Yaroslavtsev AA, Ke L, Shatruk M, Kovnir K. As-Se Pentagonal Linkers to Induce Chirality and Polarity in Mixed-Valent Fe-Se Tetrahedral Chains Resulting in Hidden Magnetic Ordering. J Am Chem Soc 2022; 144:11283-11295. [PMID: 35700396 DOI: 10.1021/jacs.2c02936] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A novel mixed-valent hybrid chiral and polar compound, Fe7As3Se12(en)6(H2O), has been synthesized by a single-step solvothermal method. The crystal structure consists of 1D [Fe5Se9] chains connected via [As3Se2]-Se pentagonal linkers and charge-balancing interstitial [Fe(en)3]2+ complexes (en = ethylenediamine). Neutron powder diffraction verified that interstitial water molecules participate in the crystal packing. Magnetic polarizability of the produced compound was confirmed by X-ray magnetic circular dichroism (XMCD) spectroscopy. X-ray absorption spectroscopy (XAS) and 57Fe Mössbauer spectroscopy showed the presence of mixed-valent Fe2+/Fe3+ in the Fe-Se chains. Magnetic susceptibility measurements reveal strong antiferromagnetic nearest neighbor interactions within the chains with no apparent magnetic ordering down to 2 K. Hidden short-range magnetic ordering below 70 K was found by 57Fe Mössbauer spectroscopy, showing that a fraction of the Fe3+/Fe2+ in the chains are magnetically ordered. Nevertheless, complete magnetic ordering is not achieved even at 6 K. Analysis of XAS spectra demonstrates that the fraction of Fe3+ in the chain increases with decreasing temperature. Computational analysis points out several competing ferrimagnetic ordered models within a single chain. This competition, together with variation in the Fe oxidation state and additional weak intrachain interactions, is hypothesized to prevent long-range magnetic ordering.
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Affiliation(s)
- Eranga H Gamage
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States.,Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
| | - Saeed Kamali
- Mechanical, Aerospace & Biomedical Engineering Department, University of Tennessee Space Institute, Tullahoma, Tennessee 37388, United States.,Department of Physics and Astronomy, Middle Tennessee State University, Murfreesboro, Tennessee 37132, United States
| | - Judith K Clark
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Yongbin Lee
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
| | - Philip Yox
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States.,Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
| | - Padraic Shafer
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | | | - Liqin Ke
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
| | - Michael Shatruk
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States.,National High Magnetic Field Laboratory, 1800 E Paul Dirac Dr, Tallahassee, Florida 32310, United States
| | - Kirill Kovnir
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States.,Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
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Gamage EH, Ribeiro RA, Harmer CP, Canfield PC, Ozarowski A, Kovnir K. Tuning of Cr-Cr Magnetic Exchange through Chalcogenide Linkers in Cr 2 Molecular Dimers. Inorg Chem 2022; 61:6160-6174. [PMID: 35412816 DOI: 10.1021/acs.inorgchem.2c00298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A set of three Cr-dimer compounds, Cr2Q2(en)4X2 (Q: S, Se; X: Br, Cl; en: ethylenediamine), with monoatomic chalcogenide bridges have been synthesized via a single-step solvothermal route. Chalcogenide linkers mediate magnetic exchange between Cr3+ centers, while bidentate ethylenediamine ligands complete the distorted octahedral coordination of Cr centers. Unlike the compounds previously reported, none of the chalcogenide atoms are connected to extra ligands. Magnetic susceptibility studies indicate antiferromagnetic coupling between Cr3+ centers, which are moderate in Cr2Se2(en)4X2 and stronger in Cr2S2(en)4Cl2. Fitting the magnetic data requires a biquadratic exchange term. High-frequency EPR spectra showing characteristic signals due to coupled S = 1 spin states could be interpreted in terms of the "giant spin" Hamiltonian. A fourth compound, Cr2Se8(en)4, has a single diatomic Se bridge connecting the two Cr3+ centers and shows weak ferromagnetic exchange interactions. This work demonstrates the tunability in strength and type of exchange interactions between metal centers by manipulating the interatomic distances and number of bridging chalcogenide linkers.
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Affiliation(s)
- Eranga H Gamage
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States.,Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
| | - Raquel A Ribeiro
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States.,Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, United States
| | - Colin P Harmer
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States.,Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
| | - Paul C Canfield
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States.,Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, United States
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, 1800 E Paul Dirac Dr, Tallahassee, Florida 32310, United States
| | - Kirill Kovnir
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States.,Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, United States
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