Effect of Chelate Ring Size in Iron(II) Isothiocyanato Complexes with Tetradentate Tripyridyl‐alkylamine Ligands on Spin Crossover Properties |
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| Authors: | Michael Leibold Sandra Kisslinger Frank W. Heinemann Frank Hampel Yuko Ichiyanagi Michael Klein Patrick Homenya Franz Renz Siegfried Schneider Markus Reiher Siegfried Schindler |
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| Affiliation: | 1. Universit?t Kassel, Fachbereich für Metallorganische Chemie, Heinrich‐Plett‐Strasse 40, 34132 Kassel, Germany;2. Justus‐Liebig‐Universit?t Gie?en, Institut für Anorganische und Analytische Chemie, Heinrich‐Buff‐Ring 17, 35392 Gie?en, Germany;3. Universit?t Erlangen‐Nürnberg, Department Chemie & Pharmazie, Anorganische Chemie, Egerlandstra?e 1, 91058 Erlangen, Germany;4. Universit?t Erlangen‐Nürnberg, Department Chemie & Pharmazie, Organische Chemie, Henkestrasse 42, 91054 Erlangen, Germany;5. Yokohama National University, Department of Physics, 79–5 Tokiwadai, Hodogaya‐ku, Yokohama 240–8501, Japan;6. Gottfried Wilhelm Leibniz Universit?t, Institut für Anorganische Chemie, Callinstr. 9, 30167 Hannover, Germany;7. Universit?t Erlangen‐Nürnberg, Department Chemie & Pharmazie, Physikalische und Theoretische Chemie, Egerlandstra?e 3, 91058 Erlangen, Germany;8. ETH Zürich, Laboratorium für Physikalische Chemie, Vladimir‐Prelog‐Weg 2, 8093 Zürich, Switzerland |
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| Abstract: | Iron(II) complexes of the type [Fe(L)(NCS)2] with tetradentate ligands L are well known to show spin crossover properties. However, this behavior is quite sensitive in regard to small changes of the ligand system. Starting from the thoroughly investigated complex [Fe(tmpa)(NCS)2] [tmpa = tris(2‐pyridylmethyl)amine, also abbreviated as tpa in the literature] we modified the ligand by increasing systematically the chelate ring sizes from 5 to 6 thus obtaining complexes [Fe(pmea)(NCS)2], [Fe(pmap)(NCS)2], and [Fe(tepa)(NCS)2] [pmea = N,N‐bis[(2‐pyridyl)methyl]‐2‐(2‐pyridyl)ethylamine, pmap = N,N‐bis[2‐(2‐pyridyl)ethyl]‐(2‐pyridyl)methylamine, and tepa = tris[2‐(2‐pyridyl)ethyl]amine]. All complexes were structurally characterized and spin crossover properties were investigated using Mößbauer spectroscopy, magnetic measurements, and IR/Raman analyses. The results demonstrated that only the iron complexes with tmpa and pmea showed spin crossover properties, whereas the complexes with the ligands pmap and tepa only formed high spin complexes. Furthermore, DFT calculations supported these findings demonstrating again the strong influence of ligand environment. Herein the effect of increasing the chelate ring sizes in iron(II) isothiocyanato complexes with tetradentate tripyridyl‐alkylamine ligands is clearly demonstrated. |
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| Keywords: | Tetradentate pyridyl ligands Spin crossover LIESST effect Mö ß bauer Iron |
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