Here we developed a new family of Zn-containing magnetic oxides of different structures by thermal decomposition of Zn(acac)2 in the reaction solution of preformed magnetite nanoparticles (NPs) stabilized by polyphenylquinoxaline. Upon an increase of the Zn(acac)2 loading from 0.15 to 0.40 mmol (vs 1 mmol of Fe(acac)3), the Zn content increases, and the Zn-containing magnetic oxide NPs preserve a spinel structure of magnetite and an initial, predominantly multicore NP morphology. X-ray photoelectron spectroscopy (XPS) of these samples revealed that the surface of iron oxide NPs is enriched with Zn, although Zn species were also found deep under the iron oxide NP surface. For all the samples, XPS also demonstrates the atom ratio of Fe(3+)/Fe(2+) = 2:1, perfectly matching Fe3O4, but not ZnFe2O4, where Fe(2+) ions are replaced with Zn(2+). The combination of XPS with other physicochemical methods allowed us to propose that ZnO forms an ultrathin amorphous layer on the surface of iron oxide NPs and also diffuses inside the magnetite crystals. At higher Zn(acac)2 loading, cubic ZnO nanocrystals coexist with magnetite NPs, indicating a homogeneous nucleation of the former. The catalytic testing in syngas conversion to methanol demonstrated outstanding catalytic properties of Zn-containing magnetic oxides, whose activities are dependent on the Zn loading. Repeat experiments carried out with the best catalyst after magnetic separation showed remarkable catalyst stability even after five consecutive catalytic runs.

Cd(II), Hg(II) and Pb(II) were reacted with nicotinamide and nicotinic acid (vitamin B 3) in the aqueous medium. The solid products obtained were formulated by comparing the experimental and calculated data for C, H, N and metal. Both produce 2:1 compounds with the metal ions. The prepared complexes were characterized by different physicochemical methods. The UV-vis, FTIR spectral analysis, TG analysis of these complexes have been discussed. The conductance behavior of the complexes indicates that all of them behave as weak electrolytes.

A new family of Ni-, Co-, and Cr-doped Zn-containing magnetic oxide nanoparticles (NPs) stabilized by polyphenylquinoxaline (PPQ) and hyperbranched pyridylphenylene polymer (PPP) has been developed. These NPs have been synthesized by thermal decomposition of Zn and doping metal acetylacetonates in the reaction solution of preformed magnetite NPs, resulting in single-crystal NPs with spinel structure. For the PPQ-capped NPs, it was demonstrated that all three types of metal species (Fe, Zn, and a doping metal) reside within the same NPs, the surface of which is enriched with Zn and a doping metal, while the deeper layers are enriched with Fe. The Cr-doped NPs at the high Cr loading are an exception due to favored deposition of Cr on magnetite located in the NP depth. The PPP-capped NPs exhibit similar morphology and crystallinity; however, the detailed study of the NP composition was barred due to the high PPP amount retained on the NP surface. The catalyst testing in syngas conversion to methanol demonstrated outstanding catalytic properties of doped Zn-containing magnetic oxides, whose activities are dependent on the doping metal content and on the stabilizing polymer. The PPP stabilization allows for better access to the catalytic species due to the open and rigid polymer architecture and most likely optimized distribution of doping species. Repeat experiments carried out after magnetic separation of catalysts from the reaction mixture showed excellent catalyst stability even after five consecutive catalytic runs.

Here, we report on the development of novel Cr-containing magnetic oxide nanoparticles (NPs) as catalysts for a syngas-tomethanol reaction which constitutes a sustainable route to obtain value-added chemicals. These NPs have been synthesized in a one-pot reaction by thermal decomposition of Cr acetylacetonate and doping metal acetylacetonates (if used) in the reaction solution of preformed magnetite NPs stabilized by polyphenylquinoxaline. For all the samples, the NP surface is enriched with Cr. At the same time, the Cr species are finely dispersed in the magnetite phase. This exposes Cr catalytic species to reacting molecules and creates an intimate contact between Cr 3 + and Fe 3 O 4 . As a result, the methanol productivity rate for the Cr-containing magnetic oxide prepared with 0.5 mmol of the Cr precursor is approximately three orders of magnitude higher than that for the conventional Cu/ZnO/Al 2 O 3 catalyst. Additional doping of this Cr-containing magnetic oxide with small amounts of Ni or La leads to even higher catalytic activity (by 40-49%).

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