SPACE ECONOM IN CHOOSE OF RADIOPROTECTIVE MATERIAL

In work were analyzed dimensional, price and mass factors of choosing the radio protective material (RPM). Analyzed materials: “Abris” RZnk-02, tungsten, lead and natural uranium; radiation source: radioactive krypton isotopes.В работе проанализированы габаритный, ценовой и весовой факторы выбора радиационно-защитных материалов (РЗМ). В работе рассмотрены различные РЗМ (природный уран, «Абрис» РЗнк-02, вольфрам, свинец) под воздействием криптона как источника излучения

Metal-insulator interplays rendered by lattice transformations and structural disorder in DOEO salts

Three salts, β-DOEONO(HO) (I), β″-DOEONO(HO) (II), and β″-DOEOHSO(HO) (III), have been synthesized and characterized by means of four-probe conductivity measurements from room temperature down to 4.2 K and X-ray single crystal analysis at room temperature and 100 K. Salt I shows dielectric properties below room temperature, and salts II and III are stable metals. The DOEO molecules in I-III are packed into organic (conductive) layers expanding along the ab plane. The layer packing in II and III is the same in the projection along the long molecular axis and is of the β″ type, but differs noticeably in the perpendicular direction. Salts I and II are not isostructural, but their structures are very similar. However, the electronic structures of II and III are very similar, which leads to quantitatively comparable conductivities for II and III. The upper bands of II and III are 1/4-filled, whereas strong dimerization and band splitting leads to effective 1/2-filling of the upper band in I, which predetermines stable metallic properties for the former and renders strong electronic correlations in the latter. A superstructure of I is formed at room temperature. The Fermi surface obtained by means of extended Hückel tight-binding (EHTB) calculations is essentially altered by the superstructure: Two parallel 1D chains instead of a set of 1D chains and closed 2D pockets visible on the substructure are realized. The Fermi surface of I consists of flattened sections that could be a source of nesting instability. In contrast, the appearance of a superstructure of II at 100 K does not alter the Fermi surface that significantly, leaving the 2D conduction system intact and the Fermi surface with enough curvature to be stable against nesting effects. The DOEO terminal ethylene groups are strongly disordered in I with position occupancies (PO) of 0.6/0.4, less disordered in III (PO: 0.8/0.2), and fully ordered in II at room temperature. All these factors together with the very large value of the dimensionless ratio U/W = 1.66, where U is an on-site Coulomb repulsion and W is a bandwidth, indicate that I most likely is a Mott insulator. Two polymorphs were observed for DOEONO(HO): β and β″.The β polymorph is a Mott insulator with U/W = 1.66, where U is an on-site Coulomb repulsion and W is a bandwidth, whereas β″ is a stable metal with a wide 1/4-filled (W = 1 eV) upper band. DOEOHSO(HO) also shows β″ packing. Electronic structures and conductivities of both β″ compounds are nearly the same. Their X-ray structures are similar, however not isostructural

Catechol-containing schiff bases on thiacalixarene: Synthesis, copper (ii) recognition, and formation of organic-inorganic copper-based materials

For the first time, a series of catechol-containing Schiff bases, tetrasubstituted at the lower rim thiacalix[4]arene derivatives in three stereoisomeric forms, cone, partial cone, and 1,3-alternate, were synthesized. The structure of the obtained compounds was proved by modern physical methods, such as NMR, IR spectroscopy, and HRMS. Selective recognition (Kb difference by three orders of magnitude) of copper (II) cation in the series of d-metal cations (Cu2+, Ni2+, Co2+, Zn2+) was shown by UV-vis spectroscopy. Copper (II) ions are coordinated at the nitrogen atom of the imine group and the nearest oxygen atom of the catechol fragment in the thiacalixarene derivatives. High thermal stable organic-inorganic copper-based materials were obtained on the base of 1,3-alternate + Cu (II) complexes