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Bauer, Wolfgang ; Pfaffeneder, Toni ; Achterhold, Klaus ; Weber, Birgit:
Complete Two-Step Spin-Transition in a 1D Chain Iron(II) Complex with a 110-K Wide Intermediate Plateau.
In: European Journal of Inorganic Chemistry.
Bd. 2011
(2011)
Heft 21
.
- S. 3183-3192.
ISSN 1099-0682
DOI: https://doi.org/10.1002/ejic.201100224
Abstract
Three new spin crossover compounds [FeL1(azpy)] (1), [FeL1(azpy)]·toluene [1(tol)] and [FeL2(azpy)] (2), where L1 and L2 are the tetradentate N2O22– coordinating Schiff base like ligands {diethyl (E,E)-2,2′-[1,2-phenyl-bis(iminomethylidyne)]bis[3-oxobutanoate]-(2-)-N,N′,O3,O3′} and {dimethyl(E,E)-2,2′-[1,2-phenyl-bis(iminomethylidyne)]bis[3-oxobutanoate]-(2-)-N,N′,O3,O3′}, respectively, and azpy = 4,4′-azopyridine are presented. All compounds have been investigated by using T-dependent susceptibility measurements, and different types of spin transitions are observed. In the case of 1 and 2, intermediate plateaus (γHS ≈ 0.5) with widths of 110 and 75 K, respectively, were observed, while for 1(tol) a gradual spin transition is obtained. Upon heating of 1(tol) above 390 K, a loss of the included solvent molecule toluene is observed, which results in a two-step spin transition of the tempered sample similar to that of 1. Mössbauer spectra of 1, 1(tol) and the tempered sample 1(temp) reveal two different iron(II) sites in the low-spin (LS) state for all three samples. T-dependent Mössbauer spectra indicate that the inequivalent iron centres are one but not the only reason for the wide plateau of 1. Results from X-ray structure analysis of 1 in the region of the plateau show the presence of two inequivalent iron centres, of which one is in the high-spin (HS) state and one in the low-spin state. The 1D chains of alternating HS and LS iron centres are arranged in a parallel manner within one layer; between the different layers, the direction of the chains rotates by 90° relative to the previous one. This cross-linked arrangement with an interlocking of the layers is most likely the reason for the appearance of the wide plateau.
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| Publikationsform: | Artikel in einer Zeitschrift |
|---|---|
| Begutachteter Beitrag: | Ja |
| Institutionen der Universität: | Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie > Professur Anorganische Chemie IV > Professur Anorganische Chemie IV - Univ.-Prof. Dr. Birgit Weber Fakultäten Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie > Professur Anorganische Chemie IV |
| Titel an der UBT entstanden: | Ja |
| Themengebiete aus DDC: | 500 Naturwissenschaften und Mathematik > 540 Chemie |
| Eingestellt am: | 26 Jul 2017 12:24 |
| Letzte Änderung: | 26 Jul 2017 12:24 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/38830 |