Kershaw Cook, LJ, Kulmaczewski, R, Barrett, SA et al. (1 more author) (2015) Iron(II) complexes of 4-sulfanyl-, 4-sulfinyl- and 4-sulfonyl-2,6-dipyrazolylpyridine ligands. A subtle interplay between spin-crossover and crystallographic phase changes. Inorganic Chemistry Frontiers, 2 (7). 662 - 670 (9). ISSN 2052-1553
Abstract
Oxidation of 4-(methylsulfanyl)-2,6-di(pyrazol-1-yl)pyridine (LSMe) with hydrogen peroxide or mCPBA yields 4-(methylsulfinyl)-2,6-di(pyrazol-1-yl)pyridine (LSOMe) and 4-(methylsulfonyl)-2,6-di(pyrazol-1-yl)-pyridine (LSO2Me), respectively. Solid [Fe(LSMe)2][ClO4]2 (1[ClO4]2) is high-spin at room temperature, and exhibits an abrupt spin-transition at T1/2 = 256 K. A shoulder on the cooling side of the χMT vs. T curve is associated with a hysteretic crystallographic phase change, occurring around T↓ = 245 K and T↑ = 258 K. The phase change involves a 180° rotation of around half the methylsulfanyl substituents in the crystal. This contrasts with the previously reported BF4 − salt of the same compound, which is isostructural to 1[ClO4]2 at room temperature but transforms to a different crystal phase in its low-spin state. Solid [Fe(LSOMe)2][BF4]2 (2[BF4]2) and [Fe(LSO2Me)2][BF4]2 (3[BF4]2) both exhibit gradual spin-crossover equilibria centred significantly above room temperature. Solution measurements show that the oxidised sulphur centers in 2[BF4]2 and 3[BF4]2 stabilise the low spin states of those complexes.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2015, Royal Society of Chemistry. This is an author produced version of a paper published in Inorganic Chemistry Frontiers. 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) |
Funding Information: | Funder Grant number EPSRC EP/I014039/1 EPSRC EP/K012568/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 06 Aug 2015 13:55 |
Last Modified: | 23 Jun 2016 03:17 |
Published Version: | http://dx.doi.org/10.1039/c5qi00083a |
Status: | Published |
Publisher: | Royal Society of Chemistry |
Identification Number: | 10.1039/c5qi00083a |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:88638 |