Volume 89, Issue 10 - Papers from the XX Mendeleev Congress on General and Applied Chemistry (Mendeleev XX)

Our recent studies on the chemical reactivity of chlorine dioxide in the reactions with sulfur and oxygen containing compounds are reviewed. A special attention is given to chlorine dioxide interaction with alkyl, aryl, heteroaryl, monoterpenyl thiols, sulfides and disulfides. The data on the oxidation of monoterpene alcohols and phenols are also presented. The directions of reactions depending on the structure of the compounds were identified.

Streptococcus pneumoniae can cause many types of dangerous infectious diseases such as otitis media, pneumonia, meningitis and others that are more common in the very young and very old age. Available to date commercial vaccines based on capsular polysaccharides of S. pneumoniae of clinically important strains (first generation carbohydrate vaccines) and conjugated vaccines based on these polysaccharides (second generation carbohydrate vaccines) have certain limitations in protective efficiency. However, the efficiency of vaccines can be increased by the use of third generation vaccines based on synthetic oligosaccharide ligands representing in their structures the protective epitopes of capsular polysaccharides. The proper choice of an optimal oligosaccharide ligand is the most important step in the design of third generation carbohydrate vaccines. Herein we overview our works on the synthesis of three oligosaccharides corresponding to one, “one and a half” and two repeating units of S. pneumoniae type 14 capsular polysaccharide, immunogenic conjugates thereof and comparative immunological study of their conjugates with bovine serum albumin, which was used as a model protein carrier. The ability of obtained products to raise antibodies specific to capsular polysaccharide and homologous oligosaccharides, the induction of phagocytosis by immune antisera and active protection of immunized animals from S. pneumoniae type 14 infection were evaluated. On the basis of the results obtained tetrasaccharide comprising the repeating unit of S. pneumoniae type 14 capsular polysaccharide is an optimal carbohydrate ligand to be used as a part of the third generation carbohydrate pneumococcal vaccine.

A mini-review covers the latest achievements in the field of metal-mediated cross-coupling reactions among which are palladium-catalyzed Heck, Suzuki, cyanation and amination reactions. The aspects of the application of Pd nanoparticles (PdNPs) are discussed. The possibilities of the applications of Cu(I)-catalyzed reactions are described. Special emphasis is made on the synthesis of polymacrocyclic compounds like porphyrin dyads and triads, polyazacryptands bearing fluorophore groups using catalytic methods. The application of Pd-catalyzed CH-activation reactions for porphyrin modifications is described, the use of Lewis acids catalysis and organocatalysis for enantioselective C–C bond formation is considered with the emphasis on the application of immobilized organocatalyst.

Recent theoretical studies of the bromate electroreduction from strongly acidic solution have been overviewed in view of very high redox-charge and energy densities of this process making it attractive for electric energy sources. Keeping in mind non-electroactivity of the bromate ion the possibility to ensure its rapid transformation via a redox-mediator cycle (EC′ mechanism) is analyzed. Alternative route via the bromine/bromide redox couple and the comproportionation reaction inside the solution phase is considered within the framework of several theoretical approaches based on the conventional Nernst layer model, or on its recently proposed advanced version (Generalized Nernst layer model), on the convective diffusion transport equations. This analysis has revealed that this process corresponds to a novel (EC″) electrochemical mechanism since the transformation of the principal oxidant (bromate) is carried out via autocatalytic redox cycle where the bromate consumption leads to progressive accumulation of the bromine/bromide redox couple catalyzing the process. As a result, even a tracer amount of its component, bromine, in the bulk solution leads under certain conditions to extremely high current densities which may even overcome the diffusion-limited one for bromate, i.e. be well over 1 A/cm 2 for concentrated bromate solutions. This analysis allows one to expect that the hydrogen–bromate flow battery may generate very high values of both the current density and specific electric power, over 1 A/cm 2 and 1 W/cm 2 .

Toxicity and severe adverse effects are the primary cause of drug-candidate failures at the late stages of preclinical and clinical trials. Since most xenobiotics undergo biotransformations, their interaction with human organism reveals the effects produced by parent compounds and all metabolites. To increase the chances of successful drug development, estimation of the entire toxicity for drug substance and its metabolites is necessary for filtering out the potentially toxic compounds. We proposed the computational approach to the integral evaluation of xenobiotics’ toxicity based on the structural formula of the drug-like compound. In the framework of this study, the consensus QSAR model was developed based on the analysis of over 3000 compounds with information about their rat acute toxicity for intravenous route of administration. Four different numerical methods, estimating the integral toxicity, were proposed, and their comparative performance was studied using the external evaluation set consisting of 37 structures of drugs and 200 their metabolites. It was shown that, on the average, the best correspondence between the predicted and published data is obtained using the method that takes into account the estimated characteristics for both the parent compound and its most toxic metabolite.

Interrupted amperometry is a new highly sensitive method for diffusion current measuring. The main feature of the proposed technique is the use of capacitive current as the analytical signal together with the faradaic current. The conventional electrical circuit for amperometric measurements is complemented by a switcher that enables periodical interruption of the circuit. The technique was successfully applied for direct amperometric determination of lead, cadmium and iron ions, phenol and hydroquinone; for determination of dichromate ion via titration; for determination of dissolved oxygen in water by Clark-type sensor. In all the mentioned cases the achieved values of analytical characteristics are significantly better than for conventional amperometric methods. There are limitations and perspectives of the proposed technique considered.

DNA and aptasensors are widely used for fast and reliable detection of disease biomarkers, pharmaceuticals, toxins, metabolites and other species necessary for biomedical diagnostics. In the overview, the concept of spatially distributed redox mediators is considered with particular emphasis to the signal generation and biospecific layer assembling. The application of non-conductive polymers bearing redox labels, supramolecular carriers with attached DNA aptamers and redox active dyes and E-sensor concept are considered as examples of the approach announced.

In this paper a summary of the author’s approaches for investigation of the mass spectral behavior of some chemical warfare agents (CWAs), their degradation products and metabolites, as well as the results of development of analytical methods for confirmation of nerve and blister agents application are presented. Hydrolysis and oxidation metabolites of nerve agents, sulfur mustard and lewisite were used as biomarkers of the exposure. Sensitive analytical methods have been developed for their detection, based mainly on tandem mass spectrometry coupled with liquid chromatography. Several techniques for fast screening of CWAs degradation products based on capillary electrophoresis were also proposed. Some of developed approaches were successfully applied in the frame of the proficiency testing system of the Organization for the Prohibition of Chemical Weapons.

Amorphous nanophosphors have been produced by pulsed electron beam evaporation of bulk phosphors of rare earth elements (REE) silicates and germanates with oxyapatite structure activated with europium. The processes of crystallization of amorphous nanopowders (NP) have been studied by differential scanning calorimetry and thermogravimetry (40–1400°C) methods. A modification of the Raman and IR spectra of the samples was found when the particle size decreased from bulk to nanostate due to insignificant polymerization of Si(Ge)O 4 tetrahedra. The spectral and luminescence characteristics of the bulk samples as well as nanoamorphous samples have been examined. It was established that Eu 3+ forms two types of optical centers. Upon the transition of Sr 2 Gd 8 (SiO 4 ) 6 O 2 :Eu 3+ phosphor from bulk state to nanostate during laser excitation, the luminescence intensity of Eu 3+ ions increases 10 times. Blue and white amorphous nanophosphors have been obtained for the first time by evaporation of Ca 2 M 8 (SiO 4 ) 6 O 2 :Eu (M=Y, Gd) and Ca 2 La 8 (GeO 4 )O 2 :Eu phosphors. Radiation reduction of ions Eu 3 +→Eu 2 + in electron beam has been presumably found.

In this study, we discussed the state-of-art in global energy industry in a historical retrospective and the forecast of its development for the next 25 years. At least in the nearest quarter of a century, the main source of primary energy will remain the chemical energy of different hydrocarbon fuels, including natural gas, coal, oil, and biofuels. In this context, of current importance becomes the problem of more rational utilization of produced energy. We analyzed the basic physical constraints that define a maximum efficiency of energy conversion and utiliztion of primary energy sources.

The experimental results describing electroflotation extraction process are presented and analyzed for sparingly soluble compounds of non-ferrous and rare-earth metals, the influence of the disperse phase particle size and particle surface charge on the efficiency and electroflotation rate having been determined.

The questions of an experimental study on the qualitative characteristics of iron ore raw materials (durability, reducibility, softening and melting temperatures) and their influence on indicators of blast furnace smelting (coke consumption and productivity) are considered.

The features of current state of metallurgical technology and materials science of mass high-grade steels are viewed. A promising direction for principle improvement of the complex of properties and qualitative characteristics of steel including those, which are difficult to combine, is shown. It is the development of adequate physico-chemical methods of prediction and efficient technology methods of management of non-metallic inclusions, forms of presence of impurities, phases precipitations, structural state, including uniformity over the volume of metal. Additionally this approach allows reducing costs and expanding the raw material base. Its effectiveness is illustrated by the results of research carried out for a number of groups of mass high-quality steels.

The study provides the results of structural and parametric synthesis of multifunctional power and water supply systems for gas chemical complexes and raw hydrocarbon preparation and processing facilities. These systems include their own power generator units combined with combustible and industrial waste utilization units. Methods, algorithms and system of efficiency parameters developed by us allow one to carry out scientific studies and develop new prospective power supply systems integrated with industrial processes and effective at various stages of the enterprise operation cycle.

Currently such factors as the use of heavier feedstocks, permanent strengthening of requirements to oil and gas product quality, introduction of technical regulations for oil products, which, in turn, necessitate the development of new technologies and catalysts, have a great influence on the global oil-refining and petrochemical industry development. Recently, a special attention is given to the development of new catalysts and processes for producing middle distillate fuels suitable for cold and arctic climatic conditions. Catalytic hydrodewaxing and isodewaxing processes are the most efficient in this field. Research into controlling a functional structure of catalysts and creation of catalytic systems based on zirconium dioxide modified by tungstate anions are of outstanding interest. The trend of the use of heavier petroleum feedstocks and the need to improve the oil conversion level demand will be based on destruction of high-molecular-weight compound structures with producing light and middle cuts. So, the most important processes for heavy oil residue conversion are those enabling to control transformations of resinous-asphaltenic materials by using nanoscale catalytic systems. One of the examples of the industrial implementation of technologies using suspended catalysts is the hydroconversion process implemented currently at AO TANECO (lisencer: TIPS RAS; general designer: OAO VNIPIneft).

One of the topical approaches in analysis – outside the framework of traditional ones – is the formation of an integral “image” of the object. There are several approaches to solving the issue of obtaining as much information about the sample by a certain portion of its properties or its composition as possible. The first approach is forming a visual image (diagram) of several different properties of the analyzed sample, for example, the content of certain metals, acids, volatile components and some other indicators of wine quality. The consolidated image of a sample enables us to distinguish samples identical or similar in the selected properties from crucially different ones, even in case of an acceptable change of each indicator. Or else, using the consolidated image one can evaluate the direction of an image shift of a certain sample compared to the set of standard samples. The analysis of the geometry of the sample image by diverse indicators affords ground for assumption of the reasons for this deviation, as well as identification of falsification, or even solution of a more complicated task: detecting the area of growth of raw materials. The second approach is close to the first one in terms of methodology, but it digitizes properties using detectors and presents this as an image (“visual print” of response) of signals of these detectors on some components of the sample (presence, content). The feature of this approach is the use of a detector system that is non-selective and cross-sensitive to certain sample components. These sample images are produced using a system of “electronic nose”. “Visual prints” of array signals of different character sensors contain qualitative and quantitative information about the part of the analyzed sample which is sorbed by sensors. Despite the uncertainty of this information, “electronic noses” of piezoelectric type are widely used in the analysis of samples with complex varying composition.