Composites Synthesized from Titanium,Carbon and Aluminum Powder Compositions

Russian Physics Journal - The paper presents the results of the X-ray diffraction analysis, scanning electron microscopy, and electron probe micro-analysis of the products synthesized from the...     

Band edge smearing due to compositional disorder in multi‐component d ‐dimensional alloys

Modern optoelectronic devices are usually based on multi‐component alloys. Local statistical fluctuations in the concentrations of chemically different components cause energy fluctuations experienced by charge carriers. So far the theory for compositional disorder has been developed for compounds, in which atoms of only two chemically different types can occupy sites in a given sublattice. We extend the theoretical consideration for multi‐compound alloys containing more than two chemically different semiconductor species occupying sites in the same sublattice. Different spatial dimensionalities are considered. A comparison between theoretical predictions and experimental data can be used to reveal compositional dependencies of such material parameters as the effective mass.     

Mixed initial–boundary value problem for equations of motion of Kelvin–Voigt fluids

The initial–boundary value problem for equations of motion of Kelvin–Voigt fluids with mixed boundary conditions is studied. The no-slip condition is used on some portion of the boundary, while the impermeability condition and the tangential component of the surface force field are specified on the rest of the boundary. The global-in-time existence of a weak solution is proved. It is shown that the solution is unique and depends continuously on the field of external forces, the field of surface forces, and initial data.     

Synthesis and spectroscopic investigation of the new polyfluoroalkyl-containing indazolones

Reaction of 2-perfluoroacylcycloalkane-1,3-diones and their enol methyl esters with N,N-dinucleophiles such as 4-fluorophenylhydrazine hydrochloride and pentafluorophenylhydrazine results in formation of polyfluoroalkyl-containing 1-aryl-3-polyfluoroalkyl-6,7-dihydro-1H-indazol-4(5)H-ones and 2-aryl-3-polyfluoroalkyl-6,7-dihydro-2H-indazol-4(5)H-ones respectively. Structure of compounds obtained was proved with IR, ¹H, ¹³C, ¹⁹F, ¹⁵N NMR, and mass-spectrometric methods.     

Excited-state potential surfaces of ruthenium nitrosyl complexes: conical intersections and the Jahn-Teller effect

The Jahn-Teller effect in excited states of nitrosyl complexes was analyzed in terms of the density functional theory at the B3LYP level. This effect was shown to play a role in transitions between metastable isomers and their photoactivated relaxation to the ground state. In the compounds under study, the Jahn-Teller effect can be interpreted as the Renner-Teller effect. The characteristics of the Jahn-Teller potential energy surfaces were determined.     

Regioselective synthesis of polyfluoroalkyl-substituted 7-(1<Emphasis Type="Italic">H</Emphasis>-1,2,3-triazol-1-yl)-6,7-dihydro-1<Emphasis Type="Italic">H</Emphasis>-indazol-4(5<Emphasis Type="Italic">H</Emphasis>)-ones

3-Polyfluoroalkyl-6,6-dimethyl-7-(1H-1,2,3-triazol-1-yl)-6,7-dihydro-1H-indazol-4(5H)-ones were synthesized with high regioselectivity by 1,3-dipolar cycloaddition of terminal alkynes (phenylacetylene, hex- 1-yne, hept-1-yne, and but-3-yn-1-ol) to 7-azido-6,6-dimethyl-3-polyfluoroalkyl-6,7-dihydro-1H-indazol-4(5H)-ones which were prepared by bromination of 6,6-dimethyl-3-polyfluoroalkyl-6,7-dihydro-1H-indazol- 4(5H)-ones with N-bromosuccinimide in anhydrous carbon tetrachloride, followed by treatment of the corresponding 7-bromo derivatives with sodium azide.     

Re(I) Complexes as Backbone Substituents and Cross-Linking Agents for Hybrid Luminescent Polysiloxanes and Silicone Rubbers

This study focuses on the synthesis of hybrid luminescent polysiloxanes and silicone rubbers grafted by organometallic rhenium(I) complexes using Cu(I)-catalyzed azido-alkyne cycloaddition (CuAAC). The design of the rhenium(I) complexes includes using a diimine ligand to create an MLCT luminescent center and the introduction of a triple C≡C bond on the periphery of the ligand environment to provide click-reaction capability. Poly(3-azidopropylmethylsiloxane-co-dimethylsiloxane) (N₃-PDMS) was synthesized for incorporation of azide function in polysiloxane chain. [Re(CO)₃(MeCN)(5-(4-ethynylphenyl)-2,2′-bipyridine)]OTf (Re1) luminescent complex was used to prepare a luminescent copolymer with N₃-PDMS (Re1-PDMS), while [Re(CO)₃Cl(5,5′-diethynyl-2,2′-bipyridine)] (Re2) was used as a luminescent cross-linking agent of N₃-PDMS to obtain luminescent silicone rubber (Re2-PDMS). The examination of photophysical properties of the hybrid polymer materials obtained show that emission profile of Re(I) moiety remains unchanged and metallocenter allows to control the creation of polysiloxane-based materials with specified properties.