Modification of the magnetic properties in molecular magnets based in Prussian blue analogues through adsorbed species.

RICARDO MARTÍNEZ GARCÍA; M. KNOBEL; E. REGUERA RUIZ

JOURNAL OF PHYSICS CONDENSED MATTER

IOP PUBLISHING LTD

Año: 2006 vol. 18 p. 11243 - 11254

0953-8984

The interaction of guest molecules (H2O, N2, CO2, ethanol, methanol) with the metal ions at the pore surface in porous molecular magnets (M3[Fe(CN)6]2·xH2O, M = Mn, Co, Ni, Cu) was studied by x-ray diffraction, together with M¨ossbauer and magnetic data. These compounds can be dehydrated at relatively low temperature, usually below 100 ◦C. On the removal of water a cell contraction of about 4% of the cell volume is observed. This corresponds to a shortening of the metal?metal distance and to a strengthening for the metal?metal interaction through the CN bridge groups. In these materials the outer metal (M) is always found at the pore surface and the guest?host interactions modify the electronic structure of the host solid. Such interactions and their effect on the material electronic structure were studied by M¨ossbauer spectroscopy for the guest molecules mentioned. The most pronounced metal?metal charge overlapping was observed for the host solid free of adsorbed species. When the guest molecules were absorbed the observed changes in the solid electronic structure followed the order N2 ∼ CO2 < ethanol