Kulmaczewski, R orcid.org/0000-0002-3855-4530, Bamiduro, F orcid.org/0000-0002-1914-5731, Shahid, N orcid.org/0000-0002-8090-7619 et al. (2 more authors) (2021) Structural Transformations and Spin‐Crossover in [FeL2]2+ Salts (L = 4‐{tertbutylsulfanyl}‐2,6‐di{pyrazol‐1‐yl}pyridine) − the Influence of Bulky Ligand Substituents. Chemistry: A European Journal, 27 (6). pp. 2082-2092. ISSN 0947-6539
Abstract
4‐(Tert‐butylsulfanyl)‐2,6‐di(pyrazol‐1‐yl)pyridine (L) was obtained in low yield from a one‐pot reaction of 2,4,6‐trifluoropyridine with 2‐methylpropane‐2‐thiolate and sodium pyrazolate in a 1:1:2 ratio. The materials [FeL2][BF4]2·solv (1[BF4]2·solv) and [FeL2][ClO4]2·solv (1[ClO4]2·solv; solv = MeNO2, MeCN or Me2CO) exhibit a variety of structures and spin‐state behaviors including thermal spin‐crossover (SCO). Solvent loss on heating 1[BF4]2·xMeNO2 (x ≈ 2.3) occurs in two steps. The intermediate phase exhibits hysteretic SCO around 250 K, involving a “reverse‐SCO” step in its warming cycle at a scan rate of 5 Kmin‒1. The reverse‐SCO is not observed in a slower 1 Kmin‒1 measurement, however, confirming its kinetic nature. The final product [FeL2][BF4]2·0.75MeNO2 was crystallographically characterized, and shows abrupt but incomplete SCO at 172 K which correlates with disorder of an L ligand. The asymmetric unit of 1[BF4]2·yMe2CO (y ≈ 1.6) contains five unique complex molecules, four of which undergo gradual SCO in at least two discrete steps. Low‐spin 1[ClO4 ]2·0.5Me2CO is not isostructural with its BF4− congener, and undergoes single‐crystal‐to‐single‐crystal solvent loss with a tripling of the crystallographic unit cell volume, while retaining the P ‐1 space group. Three other solvate salts undergo gradual thermal SCO. Two of these are isomorphous at room temperature, but transform to different low‐temperature phases when the materials are fully low‐spin.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2020 Wiley‐VCH GmbH. This is the peer reviewed version of the following article: Kulmaczewski, R, Bamiduro, F, Shahid, N et al. (2 more authors) (2021) Structural Transformations and Spin‐Crossover in [FeL2]2+ Salts (L = 4‐{tertbutylsulfanyl}‐2,6‐di{pyrazol‐1‐yl}pyridine) − the Influence of Bulky Ligand Substituents. Chemistry: A European Journal, 27 (6). pp. 2082-2092. ISSN 0947-6539, which has been published in final form at https://doi.org/10.1002/chem.202004072. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. |
Keywords: | spin-crossover; iron; N-ligands; symmetry breaking; X-ray diffraction |
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 EPSRC (Engineering and Physical Sciences Research Council) EP/J021156/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 21 Oct 2020 10:14 |
Last Modified: | 08 Jan 2025 12:13 |
Status: | Published |
Publisher: | Wiley |
Identification Number: | 10.1002/chem.202004072 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:166874 |