Temperature dependent phase transition XAFS study of Fe-triazole complexes for bioimaging applications

We propose the study of silica covered Fe2+ triazole nanoparticles (with a diameter of 10-50 nm), which have potential applications as thermally responsive agents in Magnetic Resonance Imaging (MRI), by means of temperature dependent XAFS measurements. In the samples under study, Fe forms polynuclear coordination complexes with triazole ligands in a chain-like fashion. It is expected that the magnetic and structural properties of the Fe-triazole nanoparticles will be affected by the synthesis route, the nanoparticle size, and doping with lanthanide elements. Spectra acquisition at temperatures ranging from 300 K to around 470 K is requested, because various types of temperature-induced transitions take place. At intermediate temperatures order-disorder transition of the chain arrangement may be detectable while in the temperature range 300-350 K, spin-crossover happens.