Coordination polymer nano-objects into ionic liquids: Nanoparticles and superstructures

A new exploit of ionic liquids as an alternative reaction media in the synthesis of cyano-bridged coordination polymers nano-objects such as nanoparticles and their superstructures is discussed. Stable colloidal solutions containing nanoparticles of cyano-bridged coordination polymers Cu-3[Fe(CN)(6)](2)/[C-n-MIM][An] (where n = 2, 4; An = BF4, Cl) or their superstructures were prepared in the corresponding 1-R-3-methylimidazolium salts [C-n-MIM][An] which acts as both the stabilizing agent and the solvent. Different conditions, such as temperature, nature of the ionic liquid counter anion and N-alkyl substituted chain length, water content and microwave action have been varied in order to check their influence on the size, the shape and the organisation of the nanoparticles. A special emphasis is devoted to detailed studies of the magnetic properties of these frozen colloids. The dynamic study shows that the relaxation of magnetisation for the nanoparticles and their superstructures is influenced by interparticle interactions leading to appearance of a cluster-glass-like behaviour in these systems. (C) 2008 Elsevier B.V. All rights reserved.