Magnetic and optical bistability driven by thermally and photoinduced intramolecular electron transfer in a molecular cobalt-iron Prussian blue analogue

Dongfeng Li (1) , Rodolphe Clérac (2) , Olivier Roubeau (2) , Etienne Harté (2) , Corine Mathonière (3) , Rémy Le Bris (3) , Stephen M. Holmes (1)

1 Department of Chemistry
2 CRPP - Centre de recherches Paul Pascal
3 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux

A soluble molecular analogue of photoresponsive Co/Fe Prussian blues is described within this report. As judged via a variety of spectroscopic, magnetic, and crystallographic methods, electron transfer within the octanuclear complex (below 250 K) converts paramagnetic red crystals into green diamagnetic ones. The color and magnetic changes are associated with the transformation of FeIIILS-CN-CoIIHS units into FeIILS-CN-CoIIILS fragments in manner that is identical to that found for the An[Co(OH2)(6-6m)][Fe(CN)6]m·xH2O (An = alkali metal cation) family of three-dimensional Prussian blues. Moreover, this intramolecular electron transfer can be quantitatively circumvented via rapid thermal quenching and reversed via simple white light irradiation at low temperatures. Remarkably the data suggests that thermally or photoinduced paramagnetic metastable phases are identical and exhibit long relaxation times that approach 10 years at 120 K.

Mots clés: Prussian blue; Electron transfer; Photomagnetism; Bistability; Cobalt; Iron

Domaines: Matériaux

Dongfeng Li, Rodolphe Clérac, Olivier Roubeau, Etienne Harté, Corine Mathonière, et al.. Magnetic and optical bistability driven by thermally and photoinduced intramolecular electron transfer in a molecular cobalt-iron Prussian blue analogue. Journal of the American Chemical Society, 2008, 130 (1), pp.252-258. ⟨10.1021/ja0757632⟩. ⟨hal-00203055⟩