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Bauer, Wolfgang ; Scherer, Wolfgang ; Altmannshofer, Sandra ; Weber, Birgit:
Two-Step versus One-Step Spin Transitions in Iron(II) 1D Chain Compounds.
In: European Journal of Inorganic Chemistry.
Bd. 2011
(2011)
Heft 18
.
- S. 2803-2818.
ISSN 1099-0682
DOI: https://doi.org/10.1002/ejic.201001363
Abstract
Eleven iron(II) 1D coordination polymers with the general formula [FeLeq(Lax)]·solvent were synthesised and characterised, where Leq = (E,E)-{diethyl 2,2′-[1,2-phenylenebis(iminomethylidyne)]bis(3-oxobutanato) (2-)-N,N′,O3,O3′} (L1) and {[3,3′]-[1,2-phenylenebis(iminomethylidyne)]bis(2,4-pentane-dionato)(2-)-N,N′,O2,O2′} (L2); Lax = 4,4′-bipyridine (bipy), 1,2-bis(4-pyridyl)ethane (bpea) and 1,3-bis(4-pyridyl)propane (bppa) and solvent = MeOH, EtOH and toluene (Tol). [FeL1(bpea)]·MeOH (3·MeOH) shows an abrupt one-step spin crossover with thermal hysteresis(27 K) and [FeL2(bppa)]·MeOH (2·MeOH), [FeL2(bpea)] (4), [FeL2(bpea)]·0.25MeOH (4·0.25MeOH) and [FeL1(bipy)]·MeOH (5·MeOH) show a two-step spin transition with an IP at γHS ≈ 0.5 (IP is intermediate plateau and γHS is high-spin mol fraction) and up to 50 K wide hysteresis loops (5·MeOH). [FeL1(bppa)] (1), [FeL2(bppa)]·EtOH (2·EtOH) and [FeL1(bpea)]·1.5Tol (3·1.5Tol) show an abrupt incomplete spin transition that stops at γHS ≈ 0.5; for [FeL1(bppa)]·0.25MeOH (1·0.25MeOH) and [FeL1(bpea)] (3), the spin transition is gradual and incomplete. The X-ray crystal structures of six complexes were determined (1, 2·MeOH, 3·MeOH, 3·1.5Tol, 4·0.25MeOH and 5·MeOH). In the case of 4·0.25MeOH, the crystal structures for the HS and LS states were dertermined; for compounds 1, 2·MeOH and 3·1.5Tol, the crystal structure of the HS and the IP state was investigated. For all complexes, the iron(II) centre is located in a distorted octahedral coordination sphere. Each axially coordinated ligand “connects” two iron(II) centres, which results in the formation of extended 1D chains with varying structures from linear (bipy) over steplike (bpea) to zigzag (bppa). Analysis of the intermolecular interactions reveals that the hysteresis width depends on both the stiffness of the axial ligand and the number of intermolecular contacts, while zigzag chains support stepwise spin transitions.
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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: | Nein |
| Themengebiete aus DDC: | 500 Naturwissenschaften und Mathematik > 540 Chemie |
| Eingestellt am: | 26 Jul 2017 14:02 |
| Letzte Änderung: | 26 Jul 2017 14:02 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/38831 |