Kulmaczewski, R orcid.org/0000-0002-3855-4530, Kershaw Cook, LJ orcid.org/0000-0003-1255-2307, Pask, CM orcid.org/0000-0002-2241-5069 et al. (2 more authors) (2022) Iron(II) Complexes of 4‑(Alkyldisulfanyl)-2,6-di(pyrazolyl)pyridine Derivatives. Correlation of Spin-Crossover Cooperativity with Molecular Structure Following Single-Crystal-to-Single-Crystal Desolvation. Crystal Growth and Design, 22 (3). pp. 1960-1971. ISSN 1528-7483
Abstract
The complex salts [Fe(L1)2]X2 (1X2; L1 = 4-(isopropyldisulfanyl)-2,6-bis(pyrazolyl)pyridine; X– = BF4–, ClO4–) form solvated crystals from common organic solvents. Crystals of 1X2·Me2CO show abrupt spin transitions near 160 K, with up to 22 K thermal hysteresis. 1X2·Me2CO cocrystallizes with other, less cooperative acetone solvates, which all transform into the same solvent-free materials 1X2·sf upon exposure to air, or mild heating. Conversion of 1X2·Me2CO to 1X2·sf proceeds in a single-crystal to single-crystal fashion. 1X2·sf are not isomorphous with the acetone solvates, and exhibit abrupt spin transitions at low temperature with hysteresis loops of 30–38 K (X– = BF4–) and 10–20 K (X– = ClO4–), depending on the measurement method. Interestingly, the desolvation has an opposite effect on the SCO temperature and hysteresis in the two salts. The hysteretic spin transitions in 1X2·Me2CO and 1X2·sf do not involve a crystallographic phase change but are accompanied by a significant rearrangement of the metal coordination sphere. Other solvates 1X2·MeNO2, 1X2·MeCN, and 1X2·H2O are mostly isomorphous with each other and show more gradual spin-crossover equilibria near room temperature. All three of these lattice types have similar unit cell dimensions and contain cations associated into chains through pairwise, intermolecular S···π interactions. Polycrystalline [Fe(L2)2][BF4]2·MeNO2 (2[BF4]2·MeNO2; L2 = 4-(methyldisulfanyl)-2,6-bis(pyrazolyl)pyridine) shows an abrupt spin transition just above room temperature, with an unsymmetrical and structured hysteresis loop, whose main features are reversible upon repeated thermal scanning.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2022 American Chemical Society. This is an author produced version of an article, published in Crystal Growth and Design. Uploaded in accordance with the publisher's self-archiving policy. |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemistry (Leeds) > Inorganic Chemistry (Leeds) The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Physics and Astronomy (Leeds) > Condensed Matter (Leeds) |
Funding Information: | Funder Grant number EPSRC (Engineering and Physical Sciences Research Council) EP/K012568/1 EPSRC (Engineering and Physical Sciences Research Council) EP/K00512X/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 07 Feb 2022 16:01 |
Last Modified: | 13 Jan 2025 09:56 |
Status: | Published |
Publisher: | American Chemical Society |
Identification Number: | 10.1021/acs.cgd.2c00005 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:183263 |