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Blagov MA, Spitsyna NG, Ovanesyan NS, Lobach AS, Zorina LV, Simonov SV, Zakharov KV, Vasiliev AN. First crystal structure of an Fe(III) anionic complex based on a pyruvic acid thiosemicarbazone ligand with Li +: synthesis, features of magnetic behavior and theoretical analysis. Dalton Trans 2023; 52:1806-1819. [PMID: 36661046 DOI: 10.1039/d2dt03630d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The iron(III) anionic complex based on a pyruvic acid thiosemicarbazone ligand with the lithium cation Li[FeIII(thpy)2]·3H2O (1) has been synthesized and characterized by FTIR spectroscopy, powder and single crystal X-ray diffraction, direct current magnetic susceptibility measurements, and 57Fe Mössbauer spectroscopy. Moreover, the molecular structure of the [Fe(thpy)2]- anion has been determined for the first time. The [Fe(thpy)2]- units in the triclinic P1̄ lattice of 1 are assembled into layers parallel to the bc plane. The Li+ cations and water molecules are located between the layers and the structure is stabilized by hydrogen bonding. The [Fe(thpy)2]- anions form interconnected dimer pairs through hydrogen bonds and short contacts with Fe⋯Fe separation of 6.7861(4) Å. According to dc magnetic measurements, compound 1 demonstrates an incipient spin-crossover transition from the LS (S = 1/2) to the HS (S = 5/2) state above 250 K. The Bleaney-Bowers equation for a model of an isolated LS dimer with a mean-field correction was applied to fit the experimental data of magnetic susceptibility dependence on temperature in the temperature range of 2-250 K. The intra-dimer J1 = -1.79(1) K and inter-dimer J2 = -0.24(3) K antiferromagnetic coupling constants were defined. The analysis of the 57Fe Mössbauer spectra at 80 K and 296 K confirms the presence of the shortened distances between the iron nuclei. Moreover, the influence of the lithium cation on the stabilization of the LS state was shown for the [Fe(thpy)2]- anion. BS-DFT calculations for the optimized structure of two isolated [Fe(thpy)2]- anions also correctly predict a weak exchange J1(calc) = -0.92 K. DFT calculations revealed the OPBE (GGA-type) functional that correctly predicts the spin-crossover transition for the iron(III) thpy compounds. Besides, the effect of the N2O4, N2S2O2, and N2Se2O2 coordination environments on the energy stabilization of the LS state of iron(III) anionic thpy complexes was noted as well.
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Affiliation(s)
- Maxim A Blagov
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry, Russian Academy of Sciences, Chernogolovka, Moscow region 142432, Russia.,Lomonosov Moscow State University, Moscow 119991, Russia
| | - Nataliya G Spitsyna
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry, Russian Academy of Sciences, Chernogolovka, Moscow region 142432, Russia
| | - Nikolai S Ovanesyan
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry, Russian Academy of Sciences, Chernogolovka, Moscow region 142432, Russia
| | - Anatolii S Lobach
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry, Russian Academy of Sciences, Chernogolovka, Moscow region 142432, Russia
| | - Leokadiya V Zorina
- Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow region 142432, Russia.
| | - Sergey V Simonov
- Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow region 142432, Russia.
| | | | - Alexander N Vasiliev
- Lomonosov Moscow State University, Moscow 119991, Russia.,National University of Science and Technology "MISiS", Moscow 119049, Russia
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Spin crossover of a dinuclear Fe(II) complex in the trans-isomeric structure. INORG CHEM COMMUN 2022. [DOI: 10.1016/j.inoche.2022.109475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Kiehl J, Hochdörffer T, Carrella LM, Schünemann V, Nygaard MH, Overgaard J, Rentschler E. Pronounced Magnetic Bistability in Highly Cooperative Mononuclear [Fe(L npdtz) 2(NCX) 2] Complexes. Inorg Chem 2022; 61:3141-3151. [PMID: 35142508 DOI: 10.1021/acs.inorgchem.1c03491] [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
Molecular materials that exhibit stimuli-responsive bistability are promising candidates for the development of molecular switches and sensors. We herein report on the coexistence of a wide thermal hysteretic spin crossover (SCO) effect and a thermally inducible metastable high-spin state at low temperatures achieved with the two new complexes [FeII(Lnpdtz)2(NCX)2] (X = S; Se), with Lnpdtz being (2-naphthyl-5-pyridyl-1,2,4-thiadiazole) and X = S (1) and Se (2). Pronounced π-π-stacking of the aromatic side residues of the ligands enables strong intermolecular interactions, leading to abrupt SCO properties and broad magnetic hysteresis of 10 K for X = S and 58 K for X = Se. In this paper, we also present the pressure-induced spin-state switching around 0.8 GPa. A pronounced thermally induced excited spin state trapping (TIESST effect) is observed for the highly cooperative SCO compounds, which was experimentally followed by low-temperature single crystal structure analysis (20 K) and temperature-dependent Mössbauer spectroscopy.
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Affiliation(s)
- Jonathan Kiehl
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany
| | - Tim Hochdörffer
- Department of Physics, Technische Universität Kaiserslautern, Erwin-Schroedinger-Str. 46, D-67663 Kaiserslautern, Germany
| | - Luca M Carrella
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany
| | - Volker Schünemann
- Department of Physics, Technische Universität Kaiserslautern, Erwin-Schroedinger-Str. 46, D-67663 Kaiserslautern, Germany
| | - Mathilde H Nygaard
- Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus, Denmark
| | - Jacob Overgaard
- Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus, Denmark
| | - Eva Rentschler
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany
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