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Abstract Covalent semiconductors of the carbon nitride family are among the most promising systems to realize “artificial photosynthesis”, that is exploiting synthetic materials which use sunlight as an energy source to split water into its elements or converting CO2 into added value chemicals. However, the role of surface interactions and electronic properties on the reaction mechanism remain still elusive. Here, we use in-situ spectroscopic techniques that enable monitoring surface interactions in carbon nitride under artificial photosynthetic conditions. We show that the water adsorption and light illumination cause changes of the surface electron density, which activate the photocatalyst and enable the water splitting process. Our results reveal critical details on the photocatalytic mechanism, which proceeds through proton-coupled electron transfer, and provide key information to design more efficient photocatalyst for artificial photosynthesis.

Abstract Poly(heptazine imide) (PHI), a semicrystalline version of carbon nitride photocatalyst based on heptazine units, has gained significant attention for solar H2 production benefiting from its advantages including molecular synthetic versatility, excellent physicochemical stability and suitable energy band structure to capture visible photons. Typically, PHI is obtained in salt‐melt synthesis in the presence of alkali metal chlorides. Herein, we examined the role of binary alkali metal bromides (LiBr/NaBr) with diverse compositions and melting points to rationally modulate the polymerization process, structure, and properties of PHI. Solid characterizations revealed that semicrystalline PHI with a condensed π‐conjugated system and rapid charge separation rates were obtained in the presence of LiBr/NaBr. Accordingly, the apparent quantum yield of hydrogen using the optimized PHI reaches up to 62.3% at 420 nm. The density functional theory calculation shows that the dehydrogenation of the ethylene glycol has a lower energy barrier than the dehydrogenation of the other alcohols from the thermodynamic point of view. This study holds great promise for rational modulation of the structure and properties of conjugated polymeric materials.

Abstract Often, H2 is produced photocatalytically at the expense of sacrificial agents. When a sacrificial agent is selectively oxidized, this allows coupling of H2 production with synthesis of value‐added organic compounds. Herein, it is argued that the conversion of bioethanol into 1,1‐diethoxyethane with simultaneous H2 production increases the economic viability of photocatalysis and suggests a semiconductor material that is the most relevant for this purpose.

Abstract Organic semiconductors, such as carbon nitride, when employed as powders, show attractive photocatalytic properties, but their photoelectrochemical performance suffers from low charge transport capability, charge carrier recombination, and self-oxidation. High film-substrate affinity and well-designed heterojunction structures may address these issues, achieved through advanced film generation techniques. Here, we introduce a spin coating pretreatment of a conductive substrate with a multipurpose polymer and a supramolecular precursor, followed by chemical vapor deposition for the synthesis of dual-layer carbon nitride photoelectrodes. These photoelectrodes are composed of a porous microtubular top layer and an interlayer between the porous film and the conductive substrate. The polymer improves the polymerization degree of carbon nitride and introduces C-C bonds to increase its electrical conductivity. These carbon nitride photoelectrodes exhibit state-of-the-art photoelectrochemical performance and achieve high yield in C-H functionalization. This carbon nitride photoelectrode synthesis strategy may be readily adapted to other reported processes to optimize their performance.

Abstract Graphitic carbon nitride is widely studied in organic photoredox catalysis. Reductive quenching of carbon nitride excited state is postulated in many photocatalytic transformations. However, the reactivity of this species in the turn over step is less explored. In this work, we investigate electron and proton transfer from carbon nitride that is photocharged to a various extent, while the negative charge is compensated either by protons or ammonium cations. Strong stabilization of electrons by ammonium cations makes proton-coupled electron transfer uphill, and affords air-stable persistent carbon nitride radicals. In carbon nitrides, which are photocharged to a smaller extent, protons do not stabilize electrons, which results in spontaneous charge transfer to oxidants. Facile proton-coupled electron transfer is a key step in the photocatalytic oxidative-reductive cascade – tetramerization of benzylic amines. The feasibility of proton-coupled electron transfer is modulated by adjusting the extent of carbon nitride photocharging, type of counterion and temperature.

Abstract For decarbonization of ammonia production in industry, alternative methods by exploiting renewable energy sources have recently been explored. Nonetheless, they still lack yield and efficiency to be industrially relevant. Here, we demonstrate an advanced approach of nitrogen fixation to synthesize ammonia at ambient conditions via laser–induced multiphoton dissociation of lithium oxide. Lithium oxide is dissociated under non–equilibrium multiphoton absorption and high temperatures under focused infrared light, and the generated zero–valent metal spontaneously fixes nitrogen and forms a lithium nitride, which upon subsequent hydrolysis generates ammonia. The highest ammonia yield rate of 30.9 micromoles per second per square centimeter is achieved at 25 °C and 1.0 bar nitrogen. This is two orders of magnitude higher than state–of–the–art ammonia synthesis at ambient conditions. The focused infrared light here is produced by a commercial simple CO2 laser, serving as a demonstration of potentially solar pumped lasers for nitrogen fixation and other high excitation chemistry. We anticipate such laser-involved technology will bring unprecedented opportunities to realize not only local ammonia production but also other new chemistries .

The article presents comparative analysis of modular training as a teaching tool against traditional methods and techniques in educational institutions, particularly in higher education. Being one of the forms of interactive learning, modular training ensures efficient intermutual development of all members of educational process. It increases active learning and improves critical thinking, as well as problem solving skills. Based on several years of experimental research this article gives recommendations on modular training for improving knowledge in emergency first aid treatment for students of various educational institutions. It also briefly describes the algorithm of introducing elements of modular training for implementation of Health and Safety course.

Continuous improvement of the technical equipment of sea vessels is inevitably accompanied by the development and complication of the training base for marine specialists. Simulator training based on a computer model of operating the units of the liquefied natural gas tanker of the Veliky Novgorod type includes interactive computer programs for learning management, created using the e-Tutor computer module included in the simulator delivery set. In the course of systematizing the experience of using specialized programming tools for educational and research activities of students in organizing and conducting simulator training for electrical engineers on computer simulation models of sea vessels, a system of conventional graphic symbols for the elements of the flowchart of the training exercise program has been formed and their description has been given. Training and control exercises include familiarization with the mnemonic diagrams of the integrated marine vessel automation system and assessment of the state of the ship's electrical power system with their help, starting the propulsion electrical installation, providing energy to the operating propulsion electrical installation under load changes, switching on the backup diesel generator unit for parallel operation with the network in normal and emergency modes, acceleration of the vessel to the given speed in accordance with the tasks of the instructor. The advantages of training programming using the e-Tutor computer module are the ability to use the simulator in self-study mode with automated teaching support.

Introduction: Ligands of adenosine A1Rs are potential candidates for the development of drugs for the treatment of paroxysmal supraventricular tachycardia, angina pectoris, hypertriglyceridemia, type 2 diabetes mellitus, neuropathic pain, and heart failure. At the same time, there is a deficiency of drugs that can regulate the functions of A1 receptors. A number of A1-antagonists are at the various stages of clinical trials; other drugs are not very selective or are characterized by an insufficient breadth of their therapeutic action. Therefore, the search for new medicinal compounds for the prevention and treatment of A1-depended diseases among nitro derivatives of tetrazolo[1,5-a]pyrimidine and 1,2,4-triazolo[1,5-a]pyrimidine is of scientific interest. Materials and methods: The search for active compounds was carried out by in silico and in vitro methods. At the first stage, a computer forecast of A1-antagonistic activity was carried out using the Microcosm BioS software. At the second stage, the prediction results were verified in vitro in a model of isolated mouse atria. Results and discussion: Based on the results of the prediction by the method of maximum similarity to standards, the most active compounds III, VIII, and XVII were selected. After testing the prediction results by the isolated atria method, the compound VIII was characterized by A1-blocking effect in vitro at a concentration of 10 μmol/L. Conclusion: The most promising compound with A1-blocking effect in vitro was identified; it is a derivative of tetrazolo[1,5-a]pyrimidine under the code of VIII. It is of interest for us for further in-depth study of its pharmacological properties.

Covalent semiconductors of the carbon nitride family are among the most promising systems to realize "artificial photosynthesis", that is exploiting synthetic materials which use sunlight as an energy source to split water into its elements or converting CO2 into added value chemicals. However, the role of surface interactions and electronic properties on the reaction mechanism remain still elusive. Here, we use in-situ spectroscopic techniques that enable monitoring surface interactions in carbon nitride under artificial photosynthetic conditions. We show that the water adsorption and light illumination cause changes of the surface electron density, which activate the photocatalyst and enable the water splitting process. Our results reveal critical details on the photocatalytic mechanism, which proceeds through proton-coupled electron transfer, and provide key information to design more efficient photocatalyst for artificial photosynthesis. In-situ monitoring of artificial photosynthesis with carbon nitride thin films reveal the critical role of surface interactions which alter surface electron density and electronic properties and facilitates the splitting of water into its elements [ABSTRACT FROM AUTHOR]

Chromoselective catalysis offers an intriguing opportunity to enable a specific reaction pathway in photocatalysis. Here, the authors look into the ability of covalent triazine frameworks to enable the synthesis of different organic compounds by using safer red light instead of harsh UV light.

According to the literature, metastatic brain damage in kidney cancer occurs in 6.5 % of patients. The introduction of new techniques associated with the use of targeted drugs, immune checkpoint inhibitors and innovative radiation therapy techniques can significantly increase patient survival. Effective drug therapy and local control of brain metastases are of paramount importance for predicting overall survival and quality of life for patients. This literature review summarizes the scientific literature data on the use of local and systemic methods of treatment in patients with metastases of kidney cancer to the brain.

Abstract Materials dictate carbon neutral industrial chemical processes. Visible‐light photoelectrocatalysts from abundant resources will play a key role in exploiting solar irradiation. Anionic doping via pre‐organization of precursors and further co‐polymerization creates tuneable semiconductors. Triazole derivative‐purpald, an unexplored precursor with sulfur (S) container, combined in different initial ratios with melamine during one solid‐state polycondensation with two thermal steps yields hybrid S‐doped carbon nitrides (C3N4). The series of S‐doped/C3N4‐based materials show enhanced optical, electronic, structural, textural, and morphological properties and exhibit higher performance in organic benzylamine photooxidation, oxygen evolution, and similar energy storage (capacitor brief investigation). 50M‐50P exhibits the highest photooxidation conversion (84 ± 3%) of benzylamine to imine at 535 nm – green light for 48 h, due to a discrete shoulder (≈700) nm, high sulfur content, preservation of crystal size, new intraband energy states, structural defects by layer distortion, and 10–16 nm pores with arbitrary depth. This work innovates by studying the concomitant relationships between: 1) the precursor decomposition while C3N4 is formed, 2) the insertion of S impurities, 3) the S‐doped C3N4 property‐activity relationships, and 4) combinatorial surface, bulk, structural, optical, and electronic characterization analysis. This work contributes to the development of disordered long‐visible‐light photocatalysts for solar energy conversion and storage.

A sodium salt of 2-(fur-2-yl)-6-nitro-1,2,4-triazolo[1,5-a]pyrimidin-7-one as a close structural analogue of ZM-241385 was obtained. This heterocycle can serve as an effector for A2a adenosine receptors and possesses antiseptic activity. The structures of compounds were confirmed based on the data of 1H, 13C NMR spectroscopy, IR spectroscopy, and an elemental analysis. The structure of sodium salt 2-furyl-6-nitro-1,2,4-triazolo[1,5-a]pyrimidin-7-one was confirmed by an X-ray diffraction analysis.

Tantalum oxynitride (TaON) has recently attracted much attention due to its excellent performance as a semiconductor. However, its shortage in separation of photogenerated charges hinders the wide application, which, fortunately, can be made up by forming heterojunctions with other photocatalysts. In this study, the rational design of an inorganic‐organic TaON/potassium poly (heptazine imide) (KPHI) heterojunction is reported to separate the photo charges on the two sides of this dyadic structure. The incorporation of 20 wt.% TaON into KPHI resulted not only in H2 generation but also in a wider set of environmental remediation applications under visible light, including Cr(VI) reduction and degradation of otherwise resilient antibiotics. 20TaON/KPHI effectively reduced 17.5 ppm Cr(VI) solution in 35 min under low‐power blue light irradiation with a rate constant which is ≈6 and 30 times higher than that of pristine KPHI and TaON, respectively. Moreover, the composite demonstrated a 2‐ and 40‐fold increase in H2 evolution rate in comparison to pure KPHI and TaON, respectively. This remarkable enhancement in photocatalytic activity is ascribed to the efficient electron‐hole separation and formation of an effective Z‐scheme heterojunction. This work offers a new paradigm for designing efficient photocatalytic systems for environmental applications under low‐power LED and natural sunlight. [ABSTRACT FROM AUTHOR]

Fabrication of hybrid photoelectrodes on a subsecond timescale with low energy consumption remains a challenge. Here, the authors report a modular approach, laser-driven transfer synthesis, to build a library of structurally defined transition metal oxide composite films, enabling the creation of materials for diverse applications.

Abstract Triethanolamine (TEOA) is one of the most commonly used sacrificial agents in photocatalysis. Due to its more complex structure compared to, for example, ethanol, and its sacrificial role in photocatalysis, it gives a mixture of products. The structures of these molecules are not usually analyzed. Herein, we obtain and isolate the products of TEOA and N‐tert‐butyl diethanolamine oxygenation under photocatalytic conditions with ≈15 % yield, and followingly characterized them by NMR and mass spectroscopy. The reaction is mediated by potassium poly(heptazine imide) (K‐PHI) in the presence of O2 and affords formyl esters of β‐hydroxyethylene formamides from the corresponding ethanolamines.

Long-lived carbon nitride radicals have been used in several photocatalytic reactions. Herein, long-lived potassium poly(heptazine imide) radicals enable synthesis of γ,γ-dichloroketones from enones by addition of CHCl2 moiety, generated from chloroform, to the C=C bond.

Abstract A combination of photochemistry and proton coupled electron transfer (PCET) is a primary strategy employed by biochemical systems and synthetic chemistry to enable uphill reactions under mild conditions. Degenerate nanometer‐sized n‐type semiconductor nanoparticles (SCNPs) with the Fermi level above the bottom of the conduction band are strongly reducing and act more like metals than semiconductors. Application of the degenerate SCNPs is limited to few examples. Herein, we load microporous potassium poly(heptazine imide) (K‐PHI) nanoparticles with electrons (e‒) and charge balancing protons (H+) in an illumination phase using sacrificial agents. e‒/H+ in the K‐PHI nanoparticles are weakly bound and therefore could be used in a range of PCET reactions in dark, such as generation of aryl radicals from aryl halides, ketyl radicals from ketones, and 6e‒/6H+ reduction of nitrobenzene to aniline. The integration of several features that until now were intrinsic for plants and natural photosynthesis into a transition metal free nanomaterial composed of abundant elements (C, N, and K) offers a powerful tool for synthetic organic chemistry.

In this work, we describe the design, synthesis, and structure-activity relationship of 6-(tetrazol-5-yl)-7-aminoazolo[1,5-a]pyrimidines as inhibitors of Casein kinase 2 (CK2). At first, we optimized the reaction conditions for the azide-nitrile cycloaddition in the series of 6-cyano-7-aminoazolopyridimines and sodium azide. The regioselectivity of this process has been shown, as the cyano group of the pyrimidine cycle was converted to tetrazole while the nitrile of the azole fragment did not react. The desired tetrazolyl-azolopyrimidines were obtained in a moderate to excellent yields (42–95%) and converted further to water soluble sodium salts by the action of sodium bicarbonate. The obtained 6-(tetrazol-5-yl)-7-aminopyrazolo[1,5-a]pyrimidines 2a–k and their sodium salts 3a–c, 3g–k showed nano to low micromolar range of CK2 inhibition while corresponding [1,2,4]triazolopyrimidines 10a–k were less active (IC50 > 10 µM). The leader compound 3-phenyl-6-(tetrazol-5-yl)-7-aminopyrazolo[1,5-a]pyrimidine 2i as CK2 inhibitor showed IC50 45 nM.

A regiospecific synthesis of N9‐alkylated purines as novel acyclic nucleosides was developed. This approach is based on reconstructive methodology involving the construction of a target heterocyclic scaffold on a readily available 5‐aminotetrazole moiety, which is subsequently cleaved under reductive conditions due to azido‐tetrazole tautomerism. It appeared that the rate of reduction for the azide fragment in 6‐nitro‐7‐alkylaminotetrazolo[1,5‐a]pyrimidines is much greater than the rate of nitro group reduction. Treatment of these heterocycles with hydrogen over a palladium catalyst resulted in the formation of triaminopyrimidines in excellent yields through the reduction of both the azide and nitro group. Triaminopyrimidines were transformed into the desired N9‐alkylated purines, and an analog of the marketed drug penciclovir was synthesized by the developed method. [ABSTRACT FROM AUTHOR]