Among two-dimensional (2D) materials, such as graphene, a new family of 2D anisotropic carbides and nitrides of early transition metals (MXenes) is very interesting because of the potential applications in electronics, medicine, and photocatalysis. In this paper, preparation, morphostructural characterization, band gaps determination, and salicylic acid photodegradation ability of Ti2C MXene and six nanocomposites consisting of the MXene modified by TiO2, Ag2O, Ag, PdO, Pd, and Au are reported. It was confirmed using electron diffraction studies, energy dispersive X-ray spectroscopy, and high-resolution transmission microscopy that metals and metal oxides occur on the MXene flakes as nanoparticles in a shape of spots. The band gaps determined experimentally using Tauc’s method are placed in the region of 0.90–1.31 eV. In recent years, the method of photocatalytic decomposition of pollutants using semiconductor photocatalysts and UV–vis energy has become increasingly important. The MXene based nanocomposites revealed high activity in the salicylic acid (SA) photodegradation reaction (86.1–97.1% of degraded SA after 3 h, concentration of SA initial solution 100 μM, the circulation rate of the SA solution 0.875 cm3/min). The interfacial charge transfer mechanism and the role of the metallic and metal oxide nanoparticles in the photocatalytic activity of the MXene based nanocomposites are presented and discussed.

Nano-titania doped with noble metals (Au/TiO2, Ag/TiO2, Pd/TiO2) has been synthesized by mild hydrolysis of the mixture of metal salts or complexes and titanium isopropoxide ((iPr-O)4Ti). After thermal decomposition of the obtained precursors, nanomaterials were formed. Morphological characterization of the nanomaterials was provided by scanning electron microscopy (SEM) and stereological analysis, determining the BET specific surface area, and BJH nanoporosity (pore volume, pore size). It has been found that the structure of nanomaterials (size of nanoparticles and agglomerates) depended strongly on the method of the (iPr-O)4Ti hydrolysis. A minor dependence on the kind of solvents and precursors of noble metals was observed. The presence of doping metal nanoparticles was confirmed by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX). Nanomaterial phases were identified by X-ray diffraction (XRD). According to the XRD patterns, Ag/TiO2 and Pd/TiO2 products with doping metals in their oxidized form contain Ag-Ti and Pd-Ti phases. Peaks of the metal oxides Ag2O and PdO are absent in the XRD patterns. The average size of TiO2 nanoparticles is situated in the region of 20–60 nm, whereas metals are present as about 10–15 nm sized particles and fine nanoparticles.

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Carbanions of sulfonyl halides and activated sulfonates add to carbonyl compounds, and so‐formed aldol‐type adducts spontaneously fragment into olefins. This transformation mimics the one‐pot Julia olefination with (hetero)aryl sulfones, but the mechanism of fragmentation involves a four‐membered intermediate, typical for reactivity of phosphorus reagents. Moreover, in contrast to the reactions of sulfones, sulfonates of fluorinated alcohols (TFE and HFI) produce byproducts that are easily removed during workup. In our report, we focus on reactions of unstabilized and semistabilized carbanion precursors: alkylsulfonates, and allyl‐ and benzylsulfonates, respectively. In particular for semistabilized systems, olefins were synthesized as predominant E isomers in good yields. The presented studies reveal that optimal reaction conditions, including the type of base and alcohol groups of the sulfonates, are different depending on stabilization of the carbanion precursors and structure of the carbonyl substrates. The practical synthetic guide is supplemented with a discussion of the mechanism, based on reactivity studies of intermediates and identification of side‐products.

The aim of this research was to observe the relationship between zeta potential, morphology, surface area, porosity, chemical composition, and ecotoxicity of nanocomposite powders such as were exhibiting good antimicrobial properties. It was observed, that nanomaterials characterized by similar morphology and zeta potential revealed the similar toxic behavior. The samples of higher agglomeration and higher zeta potential, especially Ag/TiO 2 /SiO 2 xerogel and TiO 2 /SiO 2 aerogel were generally less ecotoxic to water organisms and plants. They were also not genotoxic in concentrations up to 500 and 250 mg/L, respectively.where g = 8.90 9 10 À4 [Pa s] is the viscosity of the electrolyte solution (water at 25°C), l is the particle velocity [m/s], and e 0 = 8.85 [pF/m] is the vacuum permittivity, e r = 78.54 is the relative permittivity of the *agsolgala@gmail.com

Complementary fragmentation mechanisms of Hawkins and one-pot Julia olefinations were employed for the stereodivergent synthesis of alkenes.

Methanedisulfonyl fluoride, CH 2 (SO 2 F) 2 , transforms aromatic aldehydes into β-arylethenesulfonyl fluorides, useful substrates for the SuFEx “click”-type transformations. The reaction mimics mechanism of the Horner–Wadsworth–Emmons olefination, which runs via addition of the carbanion, followed by cyclization–fragmentation of the four-membered ring intermediate. In the absence of base, electron-rich aldehydes follow an alternative pathway of the Knoevenagel condensation to provide unsaturated 1,1-disulfonyl fluorides. We demonstrate also trapping of elusive ethene-1,1-disulfonyl fluoride, CH 2 =C(SO 2 F) 2 , with 4-(dimethylamino)pyridine (DMAP) that forms zwitterionic adduct, characterized with X-ray studies.

The aim of the presented work was to evaluate the effect of modification of titanium dioxide nanoparticles with noble metals and their oxides on selected mammalian cells. The in vitro cytotoxicity studies of titanium dioxide (TiO 2 ) nanoparticles modified with Au, Ag, Pd, Ag 2 O, and PdO with reference to the unmodified TiO 2 nanoparticles were presented. The evaluation of cytotoxic activity of the tested nanocomposite particles was carried out using three cell lines: Caco-2 colorectal epithelial adenocarcinoma cells, BJ normal human skin fibroblasts, and L929 mouse fibroblasts. The in vitro studies included determination of cell viability after 24 and 48 hours of exposure to the nanocomposite particles, using the MTT assay, as well as flow cytometry with Annexin V-FITC staining.Our results indicate that irrespectively of the kind of cell line and assay used, nanoparticles of unmodified titanium dioxide as well as those with addition of gold and palladium have a slight impact on cell viability at the investigated concentration range (10-200 μg/mL). Nanoparticles with addition of silver (Ag and Ag 2 O), were found to have significantly higher toxic effect, the level of which varied depending on the cell line and assay used.