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Spitsyna NG, Ovanesyan NS, Blagov MA. A Comparative Study of Nitrate and Iodide of the Spin-Variable Iron(III) Cation with the N4O2 Coordination Sphere by Mössbauer Spectroscopy. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY B 2022. [DOI: 10.1134/s1990793122040157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Blagov MA, Krapivin VB, Simonov SV, Spitsyna NG. A relationship between the coordination octahedron parameters and ligand conformation during spin transition in the cationic complex [N, N′-3,6-diazaoctane-1,8-diylbis(salicylidenaldiminato)]iron(iii) [FeIII(Sal2trien)]+. Russ Chem Bull 2022. [DOI: 10.1007/s11172-022-3545-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Spitsyna NG, Blagov MA, Lazarenko VA, Svetogorov RD, Zubavichus YV, Zorina LV, Maximova O, Yaroslavtsev SA, Rusakov VS, Raganyan GV, Yagubskii EB, Vasiliev AN. Peculiar Spin-Crossover Behavior in the 2D Polymer K[Fe III(5Cl-thsa) 2]. Inorg Chem 2021; 60:17462-17479. [PMID: 34757728 DOI: 10.1021/acs.inorgchem.1c01821] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A potassium salt of the N2S2O2-coordination Fe(III) anion K[Fe(5Cl-thsa)2] (1) (5Cl-thsa - 5-chlorosalicylaldehyde thiosemicarbazone) is synthesized and characterized structurally and magnetically over a wide temperature range. Two polymorphs of salt 1 characterized by the common 2D polymer nature and assigned to the same orthorhombic Pbcn space group have been identified. The molecular structure of the minor polymorph of 1 was solved and refined at 100, 250, and 300 K is shown to correspond to the LS configuration. The dominant polymorph of 1 features K+ cations disordered over a few crystallographic sites, while the minor polymorph includes fully ordered K+ cations. The major polymorph exhibits a complete three-step cooperative spin-crossover transition both in the heating and cooling modes: The first step occurs in a temperature range from 2 to 50 K; the second abrupt hysteretic step occurs from 200 to 250 K with T1/2 = 230 K and a 6 K hysteresis loop. The third gradual step occurs from 250 to 440 K. According to 57Fe Mössbauer, XRPD, and EXAFS data, the spin-crossover transition for the dominant polymorph is quite peculiar. Indeed, the increase in the HS concentration by 57% at the second step does not result in the expected significant increase in the iron(III)-ligand bond lengths. In addition, the final step of the spin conversion (ΔγHS = 26%) is associated with a structural phase transition with a symmetry lowering from the orthorhombic (Pbcn) to the monoclinic (P21/n) space group. This nontrivial phenomenon was investigated in detail by applying magnetization measurements, electron spin resonance, 57Fe Mössbauer spectroscopy, and DFT calculations. These results provide a new platform for understanding the multistep spin-crossover character in the Fe(III) thsa-complexes and related compounds.
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Affiliation(s)
- Nataliya G Spitsyna
- Institute of Problems of Chemical Physics, RAS, Chernogolovka, 142432, Russia
| | - Maxim A Blagov
- Institute of Problems of Chemical Physics, RAS, Chernogolovka, 142432, Russia
| | | | | | - Yan V Zubavichus
- Synchrotron Radiation Facility SKIF, Boreskov Institute of Catalysis, SB RAS, Koltsovo 630559, Russia
| | | | - Olga Maximova
- Lomonosov Moscow State University, Moscow 119991, Russia
| | | | | | | | - Eduard B Yagubskii
- Institute of Problems of Chemical Physics, RAS, Chernogolovka, 142432, Russia
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