Bromobismuthates of 1,1'-(1,N-Alkanediyl)bis(picolines): Synthesis, Thermal Stability, Crystal Structures, and Optical Properties
Abstract—Hybrid bromobismuthates of N-alkylated derivatives of 2- and 3-methylpyridine, (C15H20N2)2Bi2Br10 (I), (C17H24N2)2Bi2Br10 (II), (C18H26N2)3(Bi2Br9)2 (III), (C14H18N2)(H3O)BiBr6 ∙ 2H2O (IV), (C14H18N2)2BiBr6IBr2 (V), (C16H22N2)3(Bi2Br9)2 (VI), and (C18H26N2)3(Bi2Br9)2 (VII), are synthesized in concentrated HBr and characterized by physicochemical methods. The structures of complexes I–VII are studied by X-ray structure analysis (CIF files CCDC nos. 1946844–1946850). Complexes I and II contain anions [Bi2Br10] 4–. Anions [Bi2Br9] 3– are found in the structures of compounds III, VI, and VII Bis(3-methyl-1-pyridino)ethane bromobismuthate IV contains cations H3O+ and anions [BiBr6] 3– and, unlike other bromobismuthates, decomposes at low temperatures. In presence of HI vapors, double bismuthate V containing the [BiBr6] 3– and IBr2 2– anions crystallizes along with compound IV.
The following bromobismuthates of organic cations (dipyridinoalkane derivatives) are synthesized and characterized: (4-NH2PyC5)BiBr5 (I), (2-MePyC2)BiBr5 (II), (2-NH2PyC10)BiBr5 center dot 0.65H(2)O (III), (2-NH2PyC10)(4)H5O2(BiBr6)(3) (IV), (2-NH2PyD6)(2)KBi2Br11 (V), (2-NH2PyC6)H3OBiBr6 center dot 2.33H(2)O (VI), and (2-NH2PyC6)(3)(BiBr6)(2) center dot CH3CN (VII). Three compounds obtained (I-III) contain the zigzag 1D chain (BiBr5) (n) . A new type of 1D chains, (KBi2Br11) (n) , is found in the structure of compound V. Pseudo-1D chains of BiBr6 (3-) anions can be observed in the 3D structures of compounds IV, VI, and VII. The crystallographic data were deposited with the Cambridge Crystallographic Data Centre (CIF files CCDC 1569478 (I)-1569484 (VII), respectively)
The conference is devoted to fundamental problems of semiconductor physics.Main sections of the program: 1. Bulk semiconductors: electrical and optical properties, relaxation of charge carriers, ultrafast phenomena, excitons, phonons, phase transitions, ordering. 2. Surface, films, layers: epitaxy, atomic and electronic structure of the surface, adsorption and surface reactions, processes of formation (self-organization) of nanoclusters, STM and AFM, optical microscopy of the near field. 3. Heterostructures, superlattices, one-dimensional systems: structural and optical properties, electronic transport. 4. Two-dimensional systems: structural, electronic, magnetic and optical properties, tunneling, localization, phonons, plasmons, quantum Hall effect, correlation effects. 5. Zero-dimensional systems (quantum dots, nanocrystals): energy spectrum, optical properties, tunnel transport. 6. Spin phenomena, spintronics, nanomagnetism. 7. Impurities and defects (bulk semiconductors and quantum-dimensional structures): impurities with shallow and deep levels, magnetic impurities, structural defects, disordered semiconductors. 8. High-frequency phenomena in semiconductors (microwave and terahertz range). 9. Carbon and graphene-like nanomaterials, transition metal dichalcogenide monolayers, perovskites, organic semiconductors, molecular systems. 10. Photonic crystals, microresonators and metamaterials. Nanophotonics. 11. Semiconductor devices: technology, research methods, and nanodevices. 12. Nano-and optomechanics. 13. Topological insulators and Weyl semimetals.Выделите текст, чтобы посмотреть примерыДелитесь своими подборкамиСоздавайте подборки переводов для учёбы, работы или просто так и используйте вместе с друзьямиПопробоватьПримерыУстановите приложение на смартфон и работайте офлайн+Установить ПереводчикСообщение отправленоОтправить ещё разПереводите в Яндекс.Браузере
The photoemission of free charge carriers into high-ohmic semiconductor created by light illumination of near-contact-area of ohmic contacts to cadmium telluride sample was investigated. It was revealed, that near-contact-area light illumination influences both on contact transition resistance and on volume conductivity of the crystal due to increasing of main charge carrier concentration. The method of separate determination of contact transition and sample volume resistances, suitable for high-ohmic semiconductors, was suggested.
A series of new type hybrid bromobismuthates formed by various pyrazinium cations were isolated and studied. In the systems initially containing iodide-anions and monocations of substituted pyrazines, the complexes on the base of doubly-charged cations of substituted pyrazines instead of ones based on corresponding monocations were surprisingly formed. The variation of substituted pyrazinium cation affects not only the crystal structures of hybrid bromobismuthates via tuning the nuclearity of the anions but also the hydrolytic stability of the compounds. Thorough structural study of hydrolytic transformations was performed for halobismuthates for the first time. The results revealed stepwise course of the process affording several products. Spectral studies of the complexes evidence that the values of optical band gaps (Eg) are low in comparison with those for similar systems which is most likely due to the cooperative effect involving the nature of the corresponding cations together with the features of the supramolecular structures of the complexes.
The New Russian Encyclopedia is a fundamental reference publication in 18 volumes that characterizes nature, population, economy, history, science, art, technology and other important aspects. Contains about 60,000 articles, about 30,000 biographies, about 15,000 color illustrations, maps, charts, diagrams, tables. Leaves since 2003.
Rigid amphipathic fusion inhibitors are potent broad-spectrum antivirals based on the perylene scaffold, usually decorated with a hydrophylic group linked via ethynyl or triazole. We have sequentially simplified these structures by removing sugar moiety, then converting uridine to aniline, then moving to perylenylthiophenecarboxilic acids and to perylenylcarboxylic acid. All these polyaromatic compounds, as well as antibiotic heliomycin, still showed pronounced activity against tick-borne encephalitis virus (TBEV) with limited toxicity in porcine embryo kidney (PEK) cell line. 5-(Perylen-3-yl)-2-thiophenecarboxylic acid (5a) showed the highest antiviral activity with 50% effective concentration of approx. 1.6 nM.
This volume, being the 55th of this Series, contains a wealth of information on bioactive natural products. In Chapter 1, Watson and colleagues have discussed the synthesis of monoterpene indole alkaloids, an important class of structurally diverse natural products, with respect to conventional and biomimetic synthetic approaches.
Titanocene(III) has been widely used in the synthesis of complex organic molecules and natural products including polyketides, phenylpropanoids, antibiotics, and alkaloids. Oltra and coworkers have provided a review on the stereoselective synthesis of natural products facilitated by titanocene(III) in Chapter 2.
About 70 biologically active macrocyclic bisbibenzyls (MBBs) have been isolated and structurally elucidated during the last 30 years. Song and Zhao, in Chapter 3, have provided a review on the synthesis of MBBs with diverse pharmacological properties.
Diabetes mellitus is the most common endocrine/metabolic disorder that poses a global health concern. Reyes and colleagues have discussed the hypoglycemic activity of some terrestrial and marine bioactive compounds with potential for treating type 2 diabetes in Chapter 4. In Chapter 5, Pietruszka and coworkers have highlighted the importance of some marine oxylipins that exhibit different bioactive properties.
Depression has become a psychiatric disorder, which leads to various disabilities. Natural compounds like polyphenols and terpenoids have antioxidant and neuroprotective properties and can be used for the treatment of depression. In Chapter 6, Rodrigues et al. review the clinical studies and trials on polyphenols and terpenoids for the treatment of various psychiatric disorders. The lipid A phosphate and their phosphorylated analogues found in Gram-negative bacteria are of major importance because they provide the host with defense against infections from various microorganisms. Paradies and Zimmermann have discussed physical characteristics, isolation, and bioactivity of lipopolysaccharides (lipid A) for developing new vaccines and therapeutics in Chapter 7.
Hydroxycinnamic acids (HCAs) are a group of phytonutrients with numerous beneficial effects on human health that are largely derived from plants. HCAs play important roles like defense against UV rays or pathogenic attack during growth and development of plants. In Chapter 8, El-Seedi and colleagues present a review focusing on the therapeutic effects of HCAs for the treatment of cancer, diabetes, pulmonary, hepatic, neuro-, and cardiovascular diseases. In Chapter 9, Pomilio and Mercader have presented the study of natural anthocyanins and other related flavonoids for the readers, highlighting their possible and preferable uses as health-protecting food dyes over synthetic ones. They have also discussed the anthocyanins isolated from Ipomoea cairica along with their QSAR studies.
Cardiovascular diseases are considered to be a major threat to health. Polyphenols and carotenoids are structurally diverse groups of bioactive compounds isolated from fruits and vegetables, carrying protective effects against endothelial dysfunction. These therapeutic effects have been explored by Yamagata in Chapter 10.
The roots of licorice and ivy leaves have been used in folk medicine and drugs since long. The biological activity of these complexes has been discussed by Yakovishin and Grishkovets in Chapter 11. In Chapter 12, the chemical and biological characteristics of amicoumacins and xenocoumacins are reviewed by Korshun et al. with reference to the preparation of antibiotics.
I hope that this volume will be received with the same enthusiasm as the earlier volumes of this long-standing series the first volume of which was published under my Editorship in 1988. I would like to express my gratitude to Ms. Taqdees Malik and Mr. Mahmood Alam for their assistance in the preparation of this volume.
Composite materials based on homogeneous perfluorinated cation exchange membranes MF-4SK and sulfonated zirconium oxide were obtained by in situ and casting methods and their transport properties and gas permeability were studied. With the introduction of sulfonated zirconia, the conductivity of in situ and casting membranes increases at room temperature by more than 1.5 and 4 times, respectively. The anion transfer numbers characterizing the undesirable anion transfer for composite membranes obtained by the in situ and casting methods decrease by more than 1.5 times (from 0.026 to 0.020 and from 0.020 to 0.014, respectively). For samples based on MF-4SK membranes and zirconium oxide, a significant (more than 3 times) decrease in hydrogen permeability was noted. The differences in the observed values of moisture content, conductivity and mutual diffusion of the obtained composite membranes are discussed.
Hybrid membranes were prepared by incorporating silica with propyl-imidazoline groups in polybenzimidazoles (phthalide-containing PBI or PBI based on 2,6- or 2,5-pyridinedicarboxylic acids). The influence effects of the silica precursor hydrolysis conditions on the conductivity of the hybrid membranes are studied. Ionic conductivity, water uptake, phosphoric acid doping, and gas permeability of the obtained materials were found to depend on the preparation method and the silica loading. The materials with 10 wt% of functionalized silica present the highest conductivity. A decrease of hydrogen permeability is observed for low silica loadings.