The Influence of Conditions of Polycondensation in Acid Medium on the Structure of Oligosilsesquioxanes with a Novel Eugenol-Containing Substituent.

Eugenol-containing oligoorganosilsesquioxanes were synthesized by the method of hydrolytic polycondensation in an active medium under various reaction conditions. The obtained products were characterized by Si NMR spectroscopy and MALDI-TOF spectrometry. It was shown that factors such as the reaction temperature, polycondensation duration, and molar ratio between the initial alkoxysilane monomer and acetic acid may affect the molecular weight characteristics and molecular structure of the formed oligomer, like the content of stressed cyclic units (T, DTT, TDT) and unstressed silsesquioxane units TD.

In situ tuning of platinum 5d valence states for four-electron oxygen reduction.

The oxygen reduction reaction (ORR) catalyzed by efficient and economical catalysts is critical for sustainable energy devices. Although the newly-emerging atomically dispersed platinum catalysts are highly attractive for maximizing atomic utilization, their catalytic selectivity and durability are severely limited by the inflexible valence transformation between Pt and supports. Here, we present a structure by anchoring Pt atoms onto valence-adjustable CuO/Cu hybrid nanoparticle supports (Pt-CuO/Cu), in which the high-valence Cu (+2) in CuO combined with zero-valent Cu (0) serves as a wide-range valence electron reservoir (0‒2e) to dynamically adjust the Pt 5d valence states during the ORR.

Modification of Epoxy Coatings with Fluorocontaining Organosilicon Copolymers.

Preparation of hydrophobic coatings is still a challenge for researchers in various fields of science. One of the easiest ways consists of the use of special modifiers. However, usually such modifiers are poorly compatible with organic polymeric matrixes, which leads to segregation of modifiers and deterioration of coating properties.

In situ Activation of Molecular Oxygen at Intermetallic Spacing-Optimized Iron Network-Like Sites for Boosting Electrocatalytic Oxygen Reduction.

The oxygen reduction reaction (ORR) catalyzed by transition-metal single-atom catalysts (SACs) is promising for practical applications in energy-conversion devices, but great challenges still remain due to the sluggish kinetics of O═O cleavage. Herein, a kind of high-density iron network-like sites catalysts are constructed with optimized intermetallic distances on an amino-functionalized carbon matrix (Fe-HDNSs). Quasi-in situ soft X-ray absorption spectroscopy and in situ synchrotron infrared characterizations demonstrate that the optimized intermetallic distances in Fe-HDNSs can in situ activate the molecular oxygen by fast electron compensation through the hybridized Fe 3d‒O 2p, which efficiently facilitates the cleavage of the O═O bond to *O species and highly suppresses the side reactions for an accelerated kinetics of the 4e ORR.

Microfluidically Assisted Synthesis of Calcium Carbonate Submicron Particles with Improved Loading Properties.

The development of advanced methods for the synthesis of nano- and microparticles in the field of biomedicine is of high interest due to a range of reasons. The current synthesis methods may have limitations in terms of efficiency, scalability, and uniformity of the particles. Here, we investigate the synthesis of submicron calcium carbonate using a microfluidic chip with a T-shaped oil supply for droplet-based synthesis to facilitate control over the formation of submicron calcium carbonate particles.

Using Metal-Organic Framework HKUST-1 for the Preparation of High-Conductive Hybrid Membranes Based on Multiblock Copolymers for Fuel Cells.

Novel proton-conducting hybrid membranes consisting of sulfonated multiblock copolymer of polysulfone and polyphenylsulfone (SPES) reinforced with a HKUST-1 metal-organic framework (MOF) (5, 10, and 20 wt. %) were prepared and characterized for fuel cell applications. The presence of the MOF in the copolymer was confirmed by means of FE-SEM and EDS.

Electrochemical Detection of a Novel Pt(IV) Prodrug with the Metronidazole Axial Ligand in the Hypoxic Area.

We report herein a Pt(IV) prodrug with metronidazole in axial positions -. The nitroaromatic axial ligand was conjugated with a cisplatin scaffold to irreversibly reduce under hypoxic conditions, thereby retaining the Pt(IV) prodrug in the area of hypoxia. X-ray near-edge adsorption spectroscopy (XANES) on dried drug-preincubated tumor cell samples revealed a gradual release of cisplatin from the prodrug instead of rapid intracellular degradation.

Doxorubicin-Loaded Core-Shell UiO-66@SiO Metal-Organic Frameworks for Targeted Cellular Uptake and Cancer Treatment.

Beneficial features of biocompatible high-capacity UiO-66 nanoparticles, mesoporous SiO, and folate-conjugated pluronic F127 were combined to prepare the core-shell UiO-66@SiO/F127-FA drug delivery carrier for targeted cellular uptake in cancer treatment. UiO-66 and UiO-66-NH nanoparticles with a narrow size and shape distribution were used to form a series of core-shell MOF@SiO structures. The duration of silanization was varied to change the thickness of the SiO shell, revealing a nonlinear dependence that was attributed to silicon penetration into the porous MOF structure.

Operando Photo-Electrochemical Catalysts Synchrotron Studies.

The attempts to develop efficient methods of solar energy conversion into chemical fuel are ongoing amid climate changes associated with global warming. Photo-electrocatalytic (PEC) water splitting and CO reduction reactions show high potential to tackle this challenge. However, the development of economically feasible solutions of PEC solar energy conversion requires novel efficient and stable earth-abundant nanostructured materials.

Microfluidic Synthesis and Analysis of Bioinspired Structures Based on CaCO for Potential Applications as Drug Delivery Carriers.

Naturally inspired biomaterials such as calcium carbonate, produced in biological systems under specific conditions, exhibit superior properties that are difficult to reproduce in a laboratory. The emergence of microfluidic technologies provides an effective approach for the synthesis of such materials, which increases the interest of researchers in the creation and investigation of crystallization processes. Besides accurate tuning of the synthesis parameters, microfluidic technologies also enable an analysis of the process in situ with a range of methods.

The Rare-Earth Elements Doping of BaGdF Nanophosphors for X-ray Photodynamic Therapy.

It is known that the initiation of photodynamic therapy (PDT) in deep-seated tumors requires the use of X-rays to activate the reactive oxygen species generation in deep tissues. The aim of this paper is to synthesize X-ray nanophosphors and analyze their structural and luminescence characteristics to push the PDT process deep into the body. The article deals with BaGdF:Eu, BaGdF:Sm, and BaGdF:Tb nanophosphors synthesized using microwave synthesis.

BaGdF Nanophosphors Doped with Different Concentrations of Eu for Application in X-ray Photodynamic Therapy.

X-ray photodynamic therapy (XPDT) has been recently considered as an efficient alternative to conventional radiotherapy of malignant tissues. Nanocomposites for XPDT typically consist of two components-a nanophosphor which re-emits X-rays into visible light that in turn is absorbed by the second component, a photosensitizer, for further generation of reactive oxygen species. In this study, BaGdF nanophosphors doped with different Eu:Gd ratios in the range from 0.

Dynamic CoRu Bond Shrinkage at Atomically Dispersed Ru Sites for Alkaline Hydrogen Evolution Reaction.

Accurately manipulating the electronic structure of metal active sites under working conditions is central to developing efficient and stable electrocatalysts in industrial water-alkali electrolyzers. However, the lack of an intuitive means to capture the evolution of metal sites during the reaction state inhibits the manipulation of its electronic structure. Here, atomically dispersed Ru single-sites on cobalt nanoparticles confined onto macro-microporous frameworks (M-Co NPs@Ru SAs/NC) with tunable electron coupling effect for efficient catalysis of alkaline hydrogen evolution reaction (HER) are constructed.

Effects of Zinc Oxide Nanoparticles on Physiological and Anatomical Indices in Spring Barley Tissues.

The aim of the present work was to investigate the toxic effects of zinc oxide nanoparticles (ZnO NPs, particle size < 50 nm) on the physiological and anatomical indices of spring barley ( L.). The results show that ZnO NPs inhibited growth by affecting the chlorophyll fluorescence emissions and causing deformations of the stomatal and trichome morphology, alterations to the cellular organizations, including irregularities of the chloroplasts, and disruptions to the grana and thylakoid organizations.

Novel Approach for the Synthesis of Chlorophosphazene Cycles with a Defined Size via Controlled Cyclization of Linear Oligodichlorophosphazenes [Cl(PCl=N)-PCl][PCl].

Despite a significant number of investigations in the field of phosphazene chemistry, the formation mechanism of this class of cyclic compounds is still poorly studied. At the same time, a thorough understanding of this process is necessary, both for the direct production of phosphazene rings of a given size and for the controlled cyclization reaction when it is secondary and undesirable. We synthesized a series of short linear phosphazene oligomers with the general formula Cl[PCl2=N]n-PClPCl and studied their tendency to form cyclic structures under the influence of elevated temperatures or in the presence of nitrogen-containing agents, such as hexamethyldisilazane (HMDS) or ammonium chloride.

Preparation of Porous Polymers Based on the Building Blocks of Cyclophosphazene and Cage-like Silsesquioxane and Their Use as Basic Catalysts for Knoevenagel Reactions.

Phosphazene-containing porous materials are of a great interest due to their unique properties, caused by the synergetic presence of nitrogen and phosphorus atoms, and have found applications as adsorbents, basic catalysts, etc. On the other hand, cage-like silsesquioxanes are ideal building blocks for the preparation of covalently-linked porous materials. Here two new phosphazene-functionalized organosilsesquioxane cage-based porous polymers were synthesized successively by a Friedel-Crafts reaction of hexapyrrolylcyclotriphosphazene with octavinylsilsesquioxane in the presence of AlCl and CF SO H as catalysts.

Loading of the Model Amino Acid Leucine in UiO-66 and UiO-66-NH: Optimization of Metal-Organic Framework Carriers and Evaluation of Host-Guest Interactions.

Two metal-organic frameworks (MOFs), UiO-66 and UiO-66-NH, were considered as containers for bioactive chemicals. We provide a synthesis technique, which allowed the production of these materials suitable for biomedical applications. Both MOFs were characterized as single-phase porous materials composed of nanoparticles (30-65 nm) with a ζ-potential of more than 40 mV in water suspension.

Self-Driving Laboratories for Development of New Functional Materials and Optimizing Known Reactions.

Innovations often play an essential role in the acceleration of the new functional materials discovery. The success and applicability of the synthesis results with new chemical compounds and materials largely depend on the previous experience of the researcher himself and the modernity of the equipment used in the laboratory. Artificial intelligence (AI) technologies are the next step in developing the solution for practical problems in science, including the development of new materials.

ᶫ-Leucine Loading and Release in MIL-100 Nanoparticles.

Synthesis of the MIL-100 metal-organic framework particles was carried out by hydrothermal (HT) and microwave (MW)-assisted methods. Transmission electron microscopy showed formation of microparticles in the course of hydrothermal synthesis and nanoparticles for microwave-assisted synthesis. Powder X-ray diffraction confirmed formation of larger crystallites for hydrothermal synthesis.

Novel Copper-Containing Cytotoxic Agents Based on 2-Thioxoimidazolones.

A series of 73 ligands and 73 of their Cu and Cu copper complexes with different geometries, oxidation states of the metal, and redox activities were synthesized and characterized. The aim of the study was to establish the structure-activity relationship within a series of analogues with different substituents at the N(3) position, which govern the redox potentials of the Cu/Cu redox couples, ROS generation ability, and intracellular accumulation. Possible cytotoxicity mechanisms, such as DNA damage, DNA intercalation, telomerase inhibition, and apoptosis induction, have been investigated.

Synthesis of ZnO Nanoparticles Doped with Cobalt Using Bimetallic ZIFs as Sacrificial Agents.

We report here a simple two-stage synthesis of zinc-cobalt oxide nanoparticles. We used Zn/Co-zeolite imidazolate framework (ZIF)-8 materials as precursors for annealing and optional impregnation with a silicon source for the formation of a protective layer on the surface of oxide nanoparticles. Using bimetallic ZIFs allowed us to trace the phase transition of the obtained oxide nanoparticles from wurtzite ZnO to spinel CoO structures.

A POSS-Phosphazene Based Porous Material for Adsorption of Metal Ions from Water.

The development of adsorptive materials continues to be an important area of research for removal of heavy metal ions from waste water. The adsorption capacity can be modulated by both physical and chemical modification of the adsorbent. Herein, we combine the unique properties of polyhedral oligomeric silsesquioxane (POSS) and organocyclophosphazene as the building units to synthesize a hybrid porous material, abbreviated as PN-POSS.

Interaction of Copper-Based Nanoparticles to Soil, Terrestrial, and Aquatic Systems: Critical Review of the State of the Science and Future Perspectives.

In the past two decades, increased production and usage of metallic nanoparticles (NPs) have inevitably increased their discharge into the different compartments of the environment, which ultimately paved the way for their uptake and accumulation in various trophic levels of the food chain. Due to these issues, several questions have been raised on the usage of NPs in everyday life and have become a matter of public health concern. Among the metallic NPs, Cu-based NPs have gained popularity due to their cost-effectiveness and multifarious promising uses.

Structure of the Co Intermediate of a Cobalt Pentapyridyl Catalyst for Hydrogen Evolution Revealed by Time-Resolved X-ray Spectroscopy.

Cobalt polypyridyls are highly efficient water-stable molecular catalysts for hydrogen evolution. The catalytic mechanism explaining their activity is under debate and the main question is the nature of the involvement of pyridyls in the proton transfer: the pentapyridyl ligand, acting as a pentadentate ligand, can provide stability to the catalyst or one of the pyridines can be involved in the proton transfer. Time-resolved Co K-edge X-ray absorption spectroscopy in the microsecond time range indicates that, for the [Co (aPPy)] catalyst (aPPy=di([2,2'-bipyridin]-6-yl)(pyridin-2-yl)methanol), the pendant pyridine dissociates from the cobalt in the intermediate Co state.