Researchers in France and Italy have synthesized a series of cp-NPs with controlled size by using silica matrices with tailored pore sizes (Figure). For the first time, the size-dependence of the cp-NPs' magnetic properties has been evidenced by detailed dynamic studies, which permitted a fine characterization and a more profound comprehension of the system. 

The research groups of Yannick Guari, (Institut Charles Gerhardt in Montpellier (ICGM), France) and Claudio Sangregorio, (Consorzio INSTM in Florence, Italy) have been working for several years in the field of molecular magnetism. It was their interest in the synthesis and study of molecule-based magnets, and also in the physical properties of metal and metal oxide nanoparticles that led them to develop the present work. 'The fascinating idea of synthesizing molecule-based magnets with a restricted dimension at the nano-sized level, thus combining the advantages of molecular materials and the specificity of nano-sized objects, emerged from the synergy of both approaches' said Joulia Larionova, a member of the ICGM team. 

The results matched their expectations with the preparation of size-controlled cp-nps that present unusual magnetic behaviour that varies with the particles' size. These findings are important for future developments in this area explained Larionova, 'Given its relative youth, we believe that researchers in this field should focus, in the short term, on thoroughly studying coordination polymer nano-sized objects with the aim to better understand their physical properties.'

'There is an increasing societal demand for the emergence of new original nano-sized magnetic materials for specific applications. Coordination polymer nano-objects constitute an interesting alternative to the currently considered metal-containing nanoparticles and are promising candidates to achieve nanomaterials with tailored properties,' said Larionova.   In particular, the French and Italian collaborators believe that coordination polymer metallic NPs with magnetic properties are promising nano-materials for several applications such as medical diagnosis and sensing. They are pursuing their efforts with these objectives in mind.