Controlling Physical Properties of Iron Nanoparticles during Assembly by “Click Chemistry”

The use of chemical functionalization of nanoparticles for controlled assembly relies on selective surface modification that promotes highly specific chemical transformations. It is often also important to control physical properties of the materials produced by this approach, and in the case of iron nanoparticles, magnetic properties are often the target of the applications. Here, iron nanoparticles are assembled using “click chemistry”, with two batches of iron nanoparticles functionalized with 5-hexynoic acid and 5-azidopentanoic acid, respectively. The functionalization process and the final assembly are followed by a combination of spectroscopic techniques, scanning electron microscopy, and density functional theory calculations. Most importantly, the magnetic properties of the material produced can be retained, as demonstrated by vibrating sample magnetometer measurements, with substantial changes in the morphology of the material. The observed changes are attributed to partial oxidation of the produced functionalized surfaces, and the suggestions for further improvements are made