Interaction between dirhodium(II) tetraacetate and PAMAM dendrimer grafted onto magnetite nanoparticles: Effects on magnetic properties

In this study, we report on fabrication and characterization of a novel magnetic nanocarrier based on association of magnetite nanoparticles (NPs) with poly(amidoamine) (PAMAM) dendrimers loading dirhodium(II) tetraacetate complex (DiRh(II)). The pristine magnetite NP was coated with ATPS (3-aminopropyltriethoxysilane). The interaction between PAMAM dendrimer and DiRh(II) and its effects on magnetic properties were investigated. The magnetite spinel phase is confirmed via x-ray diffraction (XRD) and Raman spectroscopy data analysis. A mean crystallite size of 9.5 ± 0.3 nm of magnetite particles is assessed from XRD data, which is close to the values obtained via dynamic light scattering (DLS) and transmission electron microscopy micrographs. Our findings strongly suggest that the Rh(II) ions interact with lone electron pairs of nitrogen atoms in amide-II and primary amines of PAMAM surface-terminated moieties. The onset of an absorption peak at 283 nm in DiRh(II) containing sample, assigned to σ R h - L → σ ∗ R h - R h electronic transition, revealed a direct interaction between Rh(II) ions and L moieties of PAMAM dendrimer. Magnetization results indicate that the presence of DiRh(II) attached to PAMAM dendrimer leads to the strong weakening of magnetic dipole–dipole interactions in ATPS- and ATPS + PAMAM coated magnetite nanoparticles.