Olefin metathesis for the functionalization of superparamagnetic nanoparticles

The functionalization of iron oxide superparamagnetic nanoparticles (NP) is one of the most active research fields due to the necessity of robust and, particularly, reproducible methods for the attachment of new biomolecules on the surface. Olefin metathesis offers many of these features, thanks to the new family of catalysts, especially Hoveyda-Grubbs second generation. Iron oxide NP were synthesized by the decomposition of organic precursors obtaining hydrophobic Fe₃O₄ NP with oleic acid as surfactant. These NP have been functionalized by the use of olefin metathesis reaction with different ligands. The metathesis was performed between the double bond in oleic acid structure and four different molecules with a terminal olefin, methyl acrylate, 6-hexenenitrile, allyltrifluoroacetate and 3-allyloxy-1,2-propandiol, in presence of the catalyst. These new NPs were fully characterized showing the success of the functionalization, small hydrodynamic size, narrow size distribution, and stability in water. This proof of concept opens a new way for the formation of carbon–carbon bonds on the surface of NP for biomedical applications.