Graphene Oxide/Iron Oxide (GrO/FeOx) Nanocomposites for Biomedicine: Synthesis and Study

Abstract: The properties and structure of magnetic graphene oxide GrO/iron oxide FeOx nanocomposites synthesized by the mechanochemical method with different content of components GrO : FeOx (wt %), namely, 20 : 80, 50 : 50, and 80 : 20 were studied. The method of mechanochemical synthesis is a mechanical process of grinding iron oxide powder together with graphene oxide in a ball mill in an aqueous medium. The synthesized magnetic GrO/FeOx nanocomposites were studied by Raman spectroscopy, a vibrating sample magnetometer, and Mössbauer spectroscopy. The Mössbauer studies made it possible to determine the phase composition and structure of the synthesized magnetic GrO/FeOx nanocomposites. The data of Mössbauer spectroscopy showed that the GrO/FeOx composites consist of the magnetite phase Fe3O4 and magnetic nanoparticles in the paramagnetic state, which is consistent with the data of X-ray diffraction studies. Based on the results of Mössbauer spectroscopy, it was found that, in addition to magnetite, the magnetic GrO/FeOx nanocomposites contain hematite α-Fe2O3, as well as phases identified as iron carbides and iron-depleted carbon clusters. The latter were not detected by X-ray diffraction, apparently because their number is insignificant and they are in an amorphous state. The results obtained show that graphene is not just a source of carbon during grinding in a ball mill, but has its own reactivity and the ability to generate new phases during mechanochemical activation. Based on the performed Mössbauer spectral studies, we obtained unique and important information on the magnetic structure of the magnetic GrO/FeOx nanocomposites. The research results make it possible to explain the magnetic properties of magnetic nanocomposites, GrO/magnetic particles, which is important for the development and graphene oxide-based synthesis of high-performance magnetic nanocomposites for various applications, including biomedicine

Magnetic Nanocomposites Graphene Oxide/Magnetite + Cobalt Ferrite (GrO/Fe<inf>3</inf>O<inf>4</inf> + CoFe<inf>2</inf>O<inf>4</inf>) for Magnetic Hyperthermia

Abstract: In this study we have investigated new magnetic nanocomposites (MNCs) graphene oxide (GrO)/magnetite (Fe3O4) + cobalt ferrite (CoFe2O4) of various concentrations that were synthesized by the mechanochemical method—the process of mechanical grinding in a ball mill in the aqueous medium of graphene oxide and preliminarily synthesized powders of magnetite and cobalt ferrite. We have obtained and studied MNCs GrO/Fe3O4 + CoFe2O4 obtained by grinding with various contents of components (in wt %), namely: 50/40 + 10; 50/25 + 25; 50/10 + 40; and 50/0 + 50. The synthesized MNCs GrO/Fe3O4 + CoFe2O4 have been investigated by X-ray diffraction method, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, a vibrating sample magnetometer, and Mössbauer spectroscopy. With the help of Mössbauer investigations, the phase composition, magnetic state, and structure of synthesized MNCs GrO/Fe3O4 + CoFe2O4 have been established, which is important for creating high-performance materials for various applications. The heterogeneity of the MNCs obtained opens prospects for their biomedical applications

2-(Het)aryl-N-phosphorylpyrrolidines via Cyclization of Phosphorus Acid Amides: A Regioselective Approach

© 2020 Wiley-VCH GmbH A first successful synthesis of 2-(het)aryl-N-phosphorylpyrrolidines is reported starting from readily available N-(4,4-diethoxybutyl)amides of P(V) acids. A range of phenols and hydroxyl-substituted O-heterocycles may be employed into the reaction furnishing N-phosphorylated 2-(het)arylpyrrolidines with up to 90 % yield. The developed method permits a presence of sensitive to phosphorylation hydroxy groups and provides the easy and regioselective entry to target compounds

The highly regioselective synthesis of novel imidazolidin-2-ones via the intramolecular cyclization/electrophilic substitution of urea derivatives and the evaluation of their anticancer activity

A series of novel 4-(het)arylimidazoldin-2-ones were obtained by the acid-catalyzed reaction of (2,2-diethoxyethyl)ureas with aromatic and heterocyclic C-nucleophiles. The proposed approach to substituted imidazolidinones benefits from excellent regioselectivity, readily available starting materials and a simple procedure. The regioselectivity of the reaction was rationalized by quantum chemistry calculations and control experiments. The anti-cancer activity of the obtained compounds was tested in vitro