Light‐Induced Bistability in the 2 D Coordination Network {[Fe(bbtr)3][BF4]2}∞: Wavelength‐Selective Addressing of Molecular Spin States |
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| Authors: | Dr. Pradip Chakraborty Dr. Sebastien Pillet Dr. El‐Eulmi Bendeif Dr. Cristian Enachescu Dr. Robert Bronisz Prof. Andreas Hauser |
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| Affiliation: | 1. Département de chimie physique, Université de Genève, 30 Quai Ernest‐Anserment, 1211 Genève 4 (Switzerland), Fax: (+41)?22‐379‐6103;2. Laboratoire de Cristallographie, Résonance Magnétique et Modélisations, UMR CNRS 7036, Institut Jean Barriol, Université de Lorraine, 54506 Vandoeuvre‐lès‐Nancy (France);3. Faculty of Physics, Al. I. Cuza University, 700506 Iasi (Romania);4. Faculty of Chemistry, University of Wroclaw, F. Joliot‐Curie 14, 50‐383 Wroclaw (Poland) |
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| Abstract: | Whereas the neat polymeric FeII compound {[Fe(bbtr)3][ClO4]2}∞ (bbtr=1,4‐di(1,2,3‐triazol‐1‐yl)butane) shows an abrupt spin transition centered at 107 K facilitated by a crystallographic symmetry breaking, in the covalently linked 2D coordination network of {[Fe(bbtr)3][BF4]2}∞, FeII stays in the high‐spin state down to 10 K. However, strong cooperative effects of elastic origin result in reversible, persistent, and wavelength‐selective photoswitching between the low‐spin and high‐spin manifolds. This compound thus shows true light‐induced bistability below 100 K. The persistent bidirectional optical switching behavior is discussed as a function of temperature, irradiation time, and intensity. Crystallographic studies reveal a photoinduced symmetry breaking and serve to establish the correlation between structure and cooperative effects. The static and kinetic behavior is explicated within the framework of the mean‐field approximation. |
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| Keywords: | cooperative effects iron photoinduced bistability photoswitching spin crossover |
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