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Facile electrochemical graphite oxidation and functionalization with a selected array of amine moieties are carried out. The electrochemical oxidation offers the ability to preserve graphite morphological characteristics as intact adjacent surfaces yield collective van der Waals interactions. The different amine moieties are used to tether adjacent layers within graphite oxide (GO) to produce rigid framework materials. This interconnectedness is of utmost necessity for the structures to withstand cyclability in adsorptive and electronic applications. Utilizing well-ordered electrochemically-derived graphite oxide could be advantageous for the development of large-flake-size intact graphite oxide frameworks compared to inherently defective chemically-derived graphite oxide. The produced materials are extensively characterized to understand the extent, nature, and chemistry of the amine functionalization within GO domains. A balanced aromaticity in the intercalating amine species is found favorable in order to achieve a homogeneous distribution throughout graphite flakes while enhancing the interlayer spacing. Herein, notably by applying HR-TEM methods, turbostratic domains are successfully resolved in frameworks with relatively high nitrogen abundance and obtained results corroborate with 13C MAS NMR findings plausibly. The tethering mechanism induces layers rotation/twisting, giving rise to pronounced Moire patterns. The enhanced interlayer spacing in the frameworks makes them promising candidates for storage and electronic applications.

In this work the flower-like hierarchical structures (HS) based on 3D pristine ZnO, ZnO:Eu3+ and ZnO:Eu3+@Au were successfully obtained by a template-free solvothermal and deposition-precipitation method. The decolorization/photodegradation of these structures towards model organic dye (rhodamine 6G) was studied. The synthesized ZnO-based HS were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–vis and photoluminescence (PL) spectroscopies. The proposed synthesis approaches allow to obtain highly crystalline 3D ZnO, ZnO:Eu3+ and ZnO:Eu3+@Au composites. Results of scanning microscopy show that ZnO flower-like HS are assemblies from smaller components, forming larger ones, the whole ZnO structure was approximately 3 μm. Au nanoparticles (size ∼ 10 nm) are successfully deposited on ZnO HS surface. Luminescent studies show that ZnO is an ideal matrix for incorporation of Eu3+ ions in broad concentration range (Eu3+ = 1.0 at%–5.0 at%) with an efficient red luminescence. The strong UV emission in ZnO, as well as ZnO:Eu3+ HS is observed under 325 nm excitation. Doping of ZnO HS matrix by Eu3+ ions leads to the red shift of deep level emission peak (DLE). The PL intensity reaches the maximum up to 5 at% Eu3+. The photocatalytic properties of ZnO and ZnO:Eu3+@Au HS were investigated under UV–Vis light irradiation towards rhodamine 6G. The obtained results demonstrate the synergetic effect of the deposited gold nanoparticles and Eu3+ doping on photocatalytic activity of ZnO:Eu3+@Au HS in comparison to pristine ZnO and ZnO:Eu3+ HS.

ZnO (nano)structures remain of great interest in biomedical applications due to their unique properties and possible morphologies. Biocompatibility of typically fabricated ZnO structures remains questionable and they still lack desired biological functions, whence their functionalization is of high interest. In this work, we fabricated micro-sized ZnO hierarchical flower-like structures using facile template-free hydrothermal method to act as carriers for the delivery of gold nanoparticles (Au) and/or Biotin (Vitamin B) to cells. Au nanoparticles (~24 nm), as well as Biotin molecules were successfully deposited on the ZnO surface due to non-covalent physical interactions. We have then cultured two cells lines: SH-SY5Y (human malignant neural) and HEK-293 (human non-malignant) and observed that ZnO hierarchical particles exhibited cell line-dependent cytotoxicity. It appeared that further functionalization of ZnO with Au nanoparticles and subsequently with Biotin led to lower discrepancy between the two cell lines response indicating that cytotoxic pathways of pure ZnO were masked by the available surface adsorbed particles (Au/Biotin). Two-photon immunocytochemistry microscopy further confirmed that Biotin decorated particles affected neuroblastoma cells cytoskeleton. These findings contribute to the understanding of cytotoxic pathways of surface-decorated nano-micro-structures made from ZnO with two molecules typically used in anticancer and regenerative medicine therapies.

The application of ionic liquids (ILs) has grown enormously, from their use as simple solvents, catalysts, media in separation science, or electrolytes to that as task-specific, tunable molecular machines with appropriate properties. A thorough understanding of these properties and structure–property relationships is needed to fully exploit their potential, open new directions in IL-based research and, finally, properly implement the appropriate applications. In this work, we investigated the structure–properties relationships of a series of alkyltriethylammonium bis(trifluoromethanesulfonyl)imide [TEA-R][TFSI] ionic liquids in relation to their thermal behavior, structure organization, and self-diffusion coefficients in the bulk state using DSC, FT-IR, SAXS, and NMR diffusometry techniques. The phase transition temperatures were determined, indicating alkyl chain dependency. Fourier-transformed infrared spectroscopy studies revealed the structuration of the ionic liquids along with alkyl chain elongation. SAXS experiments clearly demonstrated the existence of polar/non-polar domains. The alkyl chain length influenced the expansion of the non-polar domains, leading to the expansion between cation heads in polar regions of the structured IL. 1H NMR self-diffusion coefficients indicated that alkyl chain elongation generally caused the lowering of the self-diffusion coefficients. Moreover, we show that the diffusion of anions and cations of ILs is similar, even though they vary in their size.

Endometriosis is a gynecological disease defined by the presence of endometrial tissue outside the uterus. To date, the effective treatment of this disease is still based on invasive surgery or laparoscopy. Chelidonium majus L. (Papaveraceae) belongs to medicinal, latex-bearing plants. Extracts from the plant are a rich source of pharmacologically active agents. Protoberberine compounds derived from C. majus possess anticancer and antiproliferative activities. In the present study of a rat model of endometriosis, we investigated the influence of the plant protoberberine-rich fraction (BBR) obtained from the medicinal plant C. majus on the development of endometriosis. To understand of BBR therapeutic potential for endometriosis, metabolomics has been applied to study. BBR was prepared from an ethanolic extract of dry plants C. majus. Rats (n = 16) with confirmed endometriosis were treated with BBR administered orally (1 g/kg) for 14 days. Blood serum samples were collected from all of the animals and metabolites were studied using the NMR method. The metabolomic pattern was compared before and after the protoberberine treatment. The performed analysis showed significant changes in the concentrations of metabolites that are involved in energy homeostasis, including glucose, glutamine, and lactate. Histopathological studies showed no recurrence of endometriosis loci after treatment with BBR. The results of the study found that BBR treatment prevents the recurrence of endometriosis in rats. Moreover, metabolomics profiling can be applied to better understand the mechanisms of action of these protoberberine secondary plant metabolites. Our findings provide new insights into the pharmaceutical activity of natural protoberberine plant compounds.

In this research a graphite oxide (GO) was synthesized by electrochemical oxidation of natural graphite in aqueous solution of perchloric acid. The process of anodic oxidation of graphite was performed by linear sweep voltammetry (LSV) from the rest potential of electrode to 1.4 V. In consequence of the electrochemical treatment graphite was fully transformed yielding GO. Formation of GO was proved by X-ray diffraction (XRD) and Raman spectroscopy analysis. The synthesis product was also characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS).

In the present work we demonstrate a simple and effective way to produce bulk quantities of graphene material. For the first time, graphite oxide (GO), synthesized by electrochemical treatment of natural graphite in HClO4 aqueous solution, was used to obtain thermally exfoliated-reduced graphite oxide (TRGO). Herein, GO was thermally exfoliated and reduced at 500 °C in air, giving the final product of TRGO. Due to shock treatment, the volume of the synthesized TRGO drastically increased compared to the starting GO. Furthermore, the exfoliation process resulted in a significant decrease in the concentration of oxygen functionalities. The choice of GO exfoliation temperature was preceded by thermogravimetric analysis (TGA). TRGO was characterized using X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM) analysis.

ZnO:Tb3+ hierarchical structures (HS) were synthesized via efficient and facile template-free wet chemistry methods - precipitation and solvothermal ones. Obtained Tb3+-doped HS were functionalized by organosilicon compounds (OSC) for use it as a drug carrier to loading of the doxorubicin (Dox). X-Ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectrum (EDS), UV, photoluminescence (PL) and Fourier transform infrared (FT-IR) spectroscopies, nitrogen adsorption/desorption (BET), and cytotoxicity tests were employed to characterize the obtained ZnO and ZnO:Tb3+ HS. Results showed that proposed approach allows to obtain highly crystalline microspheres composed of nanosheets. XRD analysis of the obtained samples showed presence of two-phased system: ZnO and Tb(OH)3. SEM results demonstrated that obtained ZnO:Tb3+ HS have flower-like spherical shape with mean size approximately 4 μm. The Tb3+-doping do not change the original morphology of ZnO HS. The Brunauer-Emmett-Teller (BET) measurements showed that unique morphology allowed to obtain surface area of ZnO/ZnO:Tb3+ HS in range of 5 ÷ 13 m2g-1. ZnO and ZnO:Tb3+ HS showed high drug loading and low cytotoxicity.

Chemical oxidation of graphite by strong oxidant in strong acid medium produces graphite oxide (GO) with a plausible oxidation degree, however the precursor is susceptible to exfoliation and structural deformations. In this work, we present a two-step preparation method of highly oxidized GO flakes with well-ordered layered structure. Firstly, graphite was electrooxidized in HClO4 electrolyte yielding electrochemically gathered graphite oxide (EGO). Next, EGO was chemically overoxidized by modified Hummers method to prepare overoxidized electrochemically gathered graphite oxide (OEGO). Due to the increased interlayer distances of EGO, MnO3+ ions are able to penetrate the interlayer spaces and oxidize the unreacted graphitic domains. Hence, the synthesized OEGO is characterized by minor structure deformation and high oxidation degree. In case of our investigations most of well-ordered layered domains have been preserved, in contrast to the GO obtained directly from graphite. It is also noted that the overoxidation of EGO mainly results in formation of hydroxyl and epoxy groups. Additionally, rinsing OEGO with acetone helps prevent the tearing of oxidized graphene layers by O2 evolution arising from the reaction of H2O2 with MnO2 precipitated on the surface of water-washed samples.

The 1,3-dithiole-2-thione-4,5-dithiolate (C3S52– ≡ dmit) complexes with Cu(II) in solutions and deposited into zeolite NaA and into metal–organic framework (MOF) with zeolitic imidazole structure ZIF-Cu(IM)2B were studied by UV–vis and EPR spectroscopy. UV–vis spectra show that intermolecular π–π∗ transitions existing in the visible region can be used for an identification of the molecules deposited in solid matrices. EPR of Cu(dmit)2 complexes in frozen (77 K) DMF (dimethylformamide) solution indicates tetrahedral CuS4 coordination with compressed structure of D2d symmetry and EPR parameters g|| = 2.089, g⊥ = 2.0257, A|| = 145.4 × 10−4 and A⊥ = 29.8 × 10−4 cm−1. We were looking for such complexes after impregnation of the zeolites NaA with dmit solutions. We found that the Cu(dmit)2 complex in zeolite NaA appears together with Cu(II) complexes being coordinated by host oxygen atoms. The Cu(dmit)2 complexes are, however, deformed to the elongated D2d symmetry. In ZIF-Cu(IM)2B the slightly more axially compressed tetrahedral Cu(dmit)2 complexes appear as a result of coordination of the host Cu(II) ions with captured dmit molecules. The host structure is preserved, exchange coupling between host Cu(imidazole)4 complexes is strongly weakened and separated Cu-imidazole and Cu(dmit)2 complexes can be distinguished.

SBA-3 mesoporous molecular sieves doped with transition metal ions (Fe, V, Nb and Ta) have been applied for selective oxidation of propene towards propylene oxide in the presence of N 2 O as an oxidant. The kind and amount of applied modifiers significantly affected the catalytic activity. V/SBA-3 was found to be the most active among the catalyst under study. In spite of relatively high selectivity towards propylene oxide (reaching up to 23%), the main oxidation product was still propionaldehyde. Surprisingly, CO x was not formed over V, Nb and Ta modified SBA-3 catalysts. Additional modification of V containing samples (V/SBA-3) with iron complexes resulted in the further increase in the catalysts activity for epoxidation reaction. A PO selectivity of about 20% could be achieved at a propylene conversion of 17% over mixed Fe/V/SBA-3 catalytic system.

We report the observations of electronic properties of graphene oxide and reduced graphene oxide, performed with electron paramagnetic resonance technique in a broad temperature range. Both materials were examined in pure form and saturated with air, helium, and heavy water molecules. We show that spin localization strongly depends on the type and amount of molecules adsorbed at the graphene layer edges (and possible in-plane defects). Physical and chemical states of edges play crucial role in electrical transport within graphene-based materials, with hopping as the leading mechanism of charge carrier transport. Presented results are a good basis to understand the electronic properties of other carbon structures made of graphene-like building blocks. Most active carbons show some degree of functionalization and are known of having good adsorptive properties; thus, controlling both phenomena is important for many applications. Sample treatment with temperature, vacuum, and various adsorbents allowed for th...