The modern research activity of Radiochemistry Department can be seen from the projects on some scientific directions which are now in the processing.
I. Nuclear-chemical Processes
One of the most interesting aspect of chemical transformations under the β-decay of tritium (hydrogen isotope) imbedded into the molecule is tritium application for the generation of cations as short-living reactive species that are ubiquitous as intermediates in numerous chemical reactions. To this class of ions belong tricoordinated cations of elements of 14th group with general formula R3M+ (M=C,Si,Ge,Sn.Pb) bearing positive unity charge.
The nuclear-chemical method based on the β-decay of tritium incorporated in group 14th molecules is used in our studies.
R3MT ß→R3M+ + He0 (M = C, Si, Ge, Sn, Pb)
This method provides unique possibilities to study ion-molecule reactions between cations and neutrals in gas, liquid, and solid phases. Presently, they carry out investigations applying this method in following fields:
The development of methods of generation of cations elements of of group 14th
The study of the reactions of these cations with different classes of compounds. The aim of these studies is to establish the general scheme ofinteraction of R3M+ cations with main types of nucleophiles. Ion-molecule reactions with cations labeled by tritium allow us to synthetize labeled compounds which may be used in medical and biological investigations and which hardly can be produced by conventional methods.
The study of different factors, such as temperature, pressure, aggregate state of the reaction mixture on the course of ion-molecule reactions.
The Quantum-chemistry consideration of the processes.
- T.Kochina, D.Vraznov, I.Ignatyev, E.Sinotova, M.Voronkov. Nucleogenic silylium cations and their analogs // J.Organomet. Chem. 2011. V.696. P.1331-1340.
II. Chemical sensors
This scientific direction plays a leading role in the domestic and world sensor science. It includes research and development of new types of chemical sensors, membrane and sensor arrays such as “artificial electronic tongue”, investigations of the mechanism of their operation on the basis of fundamental study of the physical and chemical properties of the membranes. The state of art and the last achievements in the field are published in the monograph “Chemical Sensors”, Editor Yu.Vlasov, Nauka, Moscow, 2011, pp.399. There are some various types of sensors under investigation: solid state glass, single crystal and polycrystalline potentiometric sensors, polymer membrane sensors, optical sensors on the base of amplifying fluorescent polymer (AFP). Sensor investigations consist of analytical properties determination and conductivity, radionuclide diffusion, structure measurements of sensor membranes.
Special attention is paid to multivariate data processing both from the electrochemical sensor arrays and also of optical spectroscopic data, such as possible modalities of multicomponent analysis of several radioactive elements in spent nuclear fuel reprocessing solutions. Other topics include the analysis of water toxicity in terms of biological organisms, the analysis of various foodstuffs, medical diagnostics, etc.
- A.V. Legin, D.O. Kirsanov, V.A. Babain, L.N. Gall, N.R. Gall Promising analytical techniques for HLW analysis in “Radioactive Waste: Sources, Types and Management”, pp.77-96, Editors: Satoshi Yuan and Wenxu Hidaka, Total Pages: 224.pp ISBN: 978-1-62100-188-1 Nova Science Publishers, NY 11788 USA.
- Yu.Ermolenko, Dm.Kalyagin, V.Kolodnikov, Yu.Vlasov Tl-selective sensor with membrane on the base of Tl4HgI6 ionic conductor Russ.J.Appl.Chem., 2013, v.86, N 2, p.209.
III. Nuclear Medicine
The area of the research belongs to development of new synthetic methods for radiopharmaceuticals (radiotracers) for Positron Emission Tomography (PET). PET diagnostic agents are radiopharmaceuticals (RPs) labeled with short-lived positron emitting radionuclides. Development of new classes of RPs is an emerging area of PET methodology researches. In the recent years the original labeling and purification strategies for 18F-fluorinated amino acids with potential application in tumors imaging by PET have been developed by Raisa N. Krasikova and her colleagues in the IHB RAS in co-operation with leading Russian groups in asymmetric synthesis institutions (INEOS, Moscow) and Bayer Shering Pharma (Germany). Raisa N. Krasikova is world recognized specialist in development of rapid, reliable and fully automated synthesis approaches and automated synthesis modules for different clinically useful 11C- and 18F-labelled radiotracers. The current interest is focused on development of nucleophilic synthesis methods for 18F-labelled hydroxyl acids (6-16F-L-FDOPS for diagnostics of pheochromocytoma and neuroblastoma) and various 18F-fluorinated receptors PET radioligands. The latter researches are performed in co-operation with Karolinska Institute, Stockholm, Sweden.
- R.N. Krasikova, O.F. Kuznetsova, O.S. Fedorova, Yu.N. Belokon, V.I. Maleev, L. Mu, S. Ametamey, P.A. Schubiger, M. Friebe, M. Berndt, N. Koglin, A. Mueller, K. Graham, L. Lehmann, L.M. Dinkelborg. 4-[18F]fluoro glutamic acid (BAY 85-8050) - a new amino acid radiotracer for PET imaging of tumors: Synthesis and in vitro characterization. J. Med. Chem. 2011; 54: 406-410.
IV. Natural Radionuclides and Nuclear Waste
Efficient reprocessing of wastes remains one of the most crucial problems in industry nowadays. Long-lived radionuclides, especially actinides, are the most hazardous components of these wastes. Their recovery from the total waste mass, before disposal or reprocessing (transmutation), should enable significantly to raise the ecological safety and efficiency of the nuclear fuel cycle.
- One of research tasks is to acquire basic data for the separation of long-lived radionuclides by using novel polyfunctional macrocyclic compounds based on phosphorylated calix[n]arene derivatives. This type of ligands, particularly those substituted at the wide rim and the phosphonate derivatives have been very little investigated so far. Metal ions usually investigated are three trivalent lanthanides (La3+, Eu3+ and Yb3+), one trivalent actinide (Am3+), two tetravalent actinides (Pu4+ and Th4+) one hexavalent actinide (UO22+) and one transition metal under its anionic form, pertechnetate TcO4-.
- Experimental studies of radiochemical pollutants in environmental waters and in tap water.
- The efficiency of the method of freezing zone for drinking water purification from impurities of inorganic nature. To measure the content of impurities before and after freeze-band used neutron activation analysis to form radionuclides 56Mn, 116mIn, 198Au. It is shown that the method of freezing zone most effective at very low speeds of the front ice (not higher than 0.15 cm / hr).
- Investigating the feasibility of thermonuclear reactions with deuterons by initiating its powerful electric discharge without the use of uranium or plutonium "detonator", ie in a controlled manner and without the formation of large amounts of radioactive fission products of uranium (plutonium).
- The search continues for the optimal conditions for the thermonuclear reactions based on the isotopic composition of the target, on the basis of which will be developed methods for the detection of related electromagnetic radiation and streams of fast neutrons.
- The study of diffusion mobility of impurity "hot" atoms at phase structural transitions.
V. Fundamental Investigations
- Chemistry and structure of complex compounds of 4d-elements, lanthanides, actinides. Preparation of ionofores for selective definition of rare-earth elements on the base imprignate polymers.
- Computer modeling of the radioactive decay , extraction and separation of isotopes, isotope exchange and other radiochemical processes. Development of calculation and training programs for the computer class of the Radiochemistry Department.