Photomagnetic CoFe Prussian blue analogues: role of the cyanide ions as active electron transfer bridges modulated by cyanide-alkali metal ion interactions.
X-ray absorption spectra at the Co L(2,3)-edges were analyzed by means of ligand field multiplet calculations in different states of three photomagnetic CoFe Prussian blue analogues of chemical formula Cs(2)Co(4)[Fe(CN)(6)](3.3) x 11 H(2)O, Rb(2)Co(4)[Fe(CN)(6)](3.3) x 11 H(2)O and Na(2)Co(4)[Fe(CN)(6)](3.3) x 11 H(2)O. These simulations of the experimental spectra allowed the quantification of the crystal field parameter (10Dq). This determination led us (i) to evidence different behaviors of the Co(III)(LS) and Co(II)(HS) ions in the three-dimensional structure related to their electronic configurations, (ii) to propose an approach based on the electronic density distribution along the Co-NC-Fe linkage to account for the energy position of the states implied in the switching properties of the compounds, and (iii) to explain the different photomagnetic properties observed as a function of the size of the inserted alkali cation by competing interactions between the cyanide ion and the transition metal ions within the CoFe cyanide bimetallic network on the one hand and the cyanide ion and the alkali metal ions on the other hand.
Cafun
Jean-Daniel
JD
Institut de Chimie Moléculaire et des Matériaux d'Orsay, UMR CNRS 8182, Equipe de Chimie Inorganique, Université Paris-Sud 11, 91405 Orsay Cedex, France.
Champion
Guillaume
G
Arrio
Marie-Anne
MA
Cartier dit Moulin
Christophe
C
Bleuzen
Anne
A
D000497:Alloys / Q000737:chemistry*; D003035:Cobalt / Q000737:chemistry; D003486:Cyanides / Q000737:chemistry*; D004583:Electrons; D005295:Ferrocyanides / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D007501:Iron / Q000737:chemistry; D008280:Magnetics; D008672:Metals, Alkali / Q000737:chemistry*; D010777:Photochemistry
D000497:Alloys; D003486:Cyanides; D005295:Ferrocyanides; D007477:Ions; D008672:Metals, Alkali; D003035:Cobalt; D007501:Iron; C000170:ferric ferrocyanide