A novel poly[(N-vinylimidazole)-co-(1-pyrenylmethyl methacrylate)] ferric complex with fluorescence and superparamagnetism

Abstract

Due to its unique physical and chemical properties, the polymer N-vinylimidazole (VI), either as a homopolymer or copolymer, has a large number of important applications. Currently, technological advances have identified further uses for it and there are practical demands for multiply functional forms of the polymer; e.g., fluorescence and magnetism in one VI-polymer material. Toward this end, a novel poly[(N-vinylimidazole)-co-(1-pyrenylmethyl methacrylate)] (VI-co-PyMMA) ferric complex prepared by complexing a VI-co-PyMMA copolymer with 1-chlorobutane and FeCl₃ in succession is presented in this work. The complexed FeCl₃, which predominately exists as the FeCl₄⁻ anion, endows the resultant material with superparamagnetism; while the presence of pyrene moieties allows the complex to exhibit additional fluorescence. Both the fluorescence and magnetism exhibit a strong dependence on the content of the complexed FeCl₃ but in opposite manners. The preferred complex, S₄, shows a balance of the properties, with a fluorescence quantum yield of 0.13 and a magnetic susceptibility of 16.1 × 10⁻⁶ emu g⁻¹. Along with re-dispersibility, this single-component fluorescent–magnetic material may replace some corresponding multi-component nanomaterials, where the polymer component acts only as a protective coating and/or an organic fluorophore and the magnetic performance is usually provided by magnetic nanoparticles (MNPs). It may find potential applications in the booming biotechnology field.