New Possibilities For Synthesis Research Articles

The Evolution of Pleconaril: Modified O-Alkyl Linker Analogs Have Biological Activity towards Coxsackievirus B3 Nancy

Coxsackieviruses type B are one of the most common causes of mild upper respiratory and gastrointestinal illnesses. At the time of writing, there are no approved drugs for effective antiviral treatment for Coxsackieviruses type B. We used the core-structure of pleconaril, a well-known antienteroviral drug candidate, for the synthesis of novel compounds with O-propyl linker modifications. Some original compounds with 4 different linker patterns, such as sulfur atom, ester, amide, and piperazine, were synthesized according to five synthetic schemes. The cytotoxicity and bioactivity of 14 target compounds towards Coxsackievirus B3 Nancy were examined. Based on the results, the values of 50% cytotoxic dose (CC50), 50% virus-inhibiting dose (IC50), and selectivity index (SI) were calculated for each compound. Several of the novel synthesized derivatives exhibited a strong anti-CVB3 activity (SI > 20 to > 200). These results open up new possibilities for synthesis of further new selective anticoxsackievirus compounds.

Ni-based catalysts prepared for CO2 reforming and decomposition of methane

Methane dry reforming (MDR) and catalytic methane decomposition (CMD) are two promising processes for syngas and H2 production, and the catalyst plays a crucial role in the two processes. Here nickel catalysts were prepared through two different routes (steam gasification (SG) method and impregnation-pyrolysis-reduction (IPR) method) and evaluated in MDR and CMD. The SG method displays an advantage of process intensification while the IPR method opens up new possibilities for synthesis of highly active and stable Ni catalysts with low nickel content (3.48 wt%). When cerium, magnesium, copper or sucrose was used as an addition agent of the catalyst, cerium and magnesium dopants can significantly enhance activity and stability of the catalysts from the SG method both in MDR and CMD. For comparison, sucrose is more efficient for the catalysts from the IPR method owing to the improved interfacial structure and interaction between metal and supports.

ZnO/ZnS (hetero)structures: ab initio investigations of polytypic behavior of mixed ZnO and ZnS compounds

The range of feasible ZnO/ZnS polytypes has been explored, predicting alternative structural arrangements compared with previously suggested or observed structural forms of ZnO/ZnS compounds, including bulk crystal structures, various nanostructures, heterostructures and heterojunctions. All calculations were performed ab initio using density functional theory–local density approximation and hybrid Heyd–Scuseria–Ernzerhof functionals. Specifically, pure ZnO and ZnS compounds and mixed ZnO1–x S x compounds (x = 0.20, 0.25, 0.33, 0.50, 0.60, 0.66 and 0.75) are investigated and a multitude of possible stable polytypes for ZnO/ZnS compounds creating new possibilities for synthesis of new materials with improved physical and chemical properties are identified.

Theoretical investigation of structural, mechanical, elastic and vibrational properties of advanced materials under extreme conditions

One of the recent trends in materials science and technology is the research of the behavior of the materials under the extreme conditions both on the theoretical and experimental basis. There are limitations of the experimental methods, however, theoretical approach can be used as a supplement to the experimental results. As a consequence, in the last two decades a vast number of structure prediction calculations have been performed on chemical systems, focusing on the high-pressure and high temperature phases. In this work, we would like to present several computational studies and their connection to the actual synthesis routes: lead sulfide (PbS), barium sulfide (BaS), and aluminum nitride (AlN). The investigated compounds were calculated on ab initio level using the most advanced tools in quantum chemistry and computational material science including Hartree-Fock Theory, Density Functional Theory (DFT) and Hybrid (B3LYP) Approximation. Their structural, mechanical, elastic and vibrational properties have been investigated and in addition, we show structure candidates as the function of size, pressure and temperature and not previously observed in any of the investigated materials thus creating new possibilities for synthesis of advanced materials with improved physical, chemical, and/or mechanical properties.

Combustion synthesis of Cu2SnSe3 thermoelectric materials

Thermoelectric materials are attractive for solar thermal energy conversion and waste heat recovery. The existing methods for fabricating thermoelectric materials involve multi-step processes with considerable time and energy consumption. Here we report a fast and one-step way to prepare thermoelectric materials by gas-pressure or high-gravity assisted combustion synthesis. Dense Cu2SnSe3 samples with a porosity below 2% were prepared from self-sustained combustion reaction of element powders. The electrical conductivity of the Cu2SnSe3 samples was greatly enhanced and the thermal conductivity was reduced by partial substitution of Sn with In. The ZT values of the un-doped and In-doped Cu2SnSe3 samples reached 0.51 and 0.62 at 773K, respectively, which are comparable to the best results reported for Cu2SnSe3 produced by other methods. Combustion synthesis offers an efficient way to prepare thermoelectric materials with reduced time and energy consumption, which may open up new possibilities for synthesis of thermoelectric materials.

Direct fabrication of highly-dense Cu2ZnSnSe4 bulk materials by combustion synthesis for enhanced thermoelectric properties

Thermoelectric materials are attractive for solar thermal energy conversion and waste heat recovery. The preparation of bulk thermoelectric materials usually involves multi-step processes with considerable time and energy consumption. Here we report an alternative way called combustion synthesis to realize one-step and fast fabrication of bulk Cu2ZnSnSe4 thermoelectric materials. The combustion synthesis was carried out in 2MPa Ar gas atmosphere or in a high-gravity field in order to reduce the porosity in samples and complete simultaneous densification during synthesis. Nearly full-dense Cu2ZnSnSe4 samples with a porosity of <1% were prepared, showing thermoelectric properties similar to those of Cu2ZnSnSe4 materials prepared by other methods. The ZT of the Cu2ZnSnSe4 samples was clearly improved by partial substitution of Sn with In, and reached 0.59 at 773K for the composition of Cu2ZnSn0.9In0.1Se4. Compared with the conventional melt growth and powder sintering methods, combustion synthesis offers a fast, one-step, and furnace-free way for directly producing bulk Cu2ZnSnSe4 samples, which may open up new possibilities for synthesis and applications of Cu2ZnSnSe4-based thermoelectric materials.

THE SUBJECTIVE DIMENSION OF NAZISM

ABSTRACTThe present historiographical review discusses the subjective dimension of Nazism, an ideology and regime that needed translation into self-definitions, gender roles, and bodily practices to implant itself in German society and mobilize it for racial war. These studies include biographies of some of the Third Reich's most important protagonists, which have important things to say about their self-understandings in conjunction with the circumstances they encountered and subsequently shaped; cultural histories of important twentieth-century figures such as film stars, housewives, or consumers, which add new insights to the ongoing debate about the Third Reich's modernity; studies that address participation in the Nazi Empire and the Holocaust through discourses and practices of comradeship, work in extermination camps, and female ‘help’ within theWehrmacht. In discussing these monographs, along the way incorporating further books and articles, the piece attempts to draw connections between specific topics and think about new possibilities for synthesis in an overcompartmentalized field. It aims less to define a ‘Nazi subject’ than to bring us closer to understanding how Hitler's movement and regime connected different, shifting subject positions through both cohesion and competition, creating a dynamic that kept producing new exclusions and violent acts.

Recent Applications of Catalytic Metal-Mediated Carbocyclizations in Asymmetric Synthesis

Catalytic transition metal mediated transformations enable a variety of novel bond constructions and open up exciting new possibilities for synthesis. To date, a relatively limited number of these reactions have been used as key strategy elements in the asymmetric total synthesis of structurally complex natural products. This review examines several recent applications wherein the subset of transition-metal-catalyzed reactions, metal-catalyzed carbocyclizations, defines the key retrosynthetic transformation in the synthetic plan. The applications chosen and analyzed so as to highlight their efficiency, brevity and intrinsic elegance of design and are placed in context by comparison to complementary classical approaches to the target structure.

New possibilities for synthesis and applications of bisphenolic polymers

New possibilities for synthesis and applications of bisphenolic polymers

Composés à structure apatite. II. — Cristallochimie des silico-apatites azotées

New possibilities for synthesis result from the introduction of nitrogen in the anionic sublattice of the apatites. They have been investigated from the structure of Sm₁₀Si₆N₂O₂₄. Because the nitrogen atoms are placed in the tetrahedral environment of the silicon atoms, their number may have a higher value. New compounds can thus be obtained where lanthanides and transition elements in a high oxydation state are simultaneously present. A lot of possibilities have been studied by considering the different crystallographic sites and their environment rather than the substitution mechanisms based on chemical analogies.