The HETTAP approach: self-assembly and metal ion sensing of dumbbell-shaped molecules and clip molecules

The pentacoordinated terpyridine-phenanthroline zinc(II) complex motif, conceived along the HETTAP concept, allows the preparation of a set of multicomponent supramolecular dumbbell and clip assemblies from various bisterpyridines. All assemblies show a notable luminescence at 350-400 nm. The formation of dumbbell [Zn2(1b)2(2b)]4+ is convincingly demonstrated from the X-ray crystal structure analysis. Both dumbbell [Zn2(1b)2(2b)]4+ and clip [Zn2(1d)(2b)]4+ allow the monitoring of Hg2+ ions due to highly selective quenching of the emission that is driven by a Zn2+ --> Hg2+ exchange process, while the more-strained clip [Zn2(1d)(2c)]4+ does not undergo such metal exchange and does not show quenching of the luminescence. Consequently, these assemblies exhibit a highly selective response due solely to supramolecular effects.     

Palladium-mediated intramolecular aryl amination on furanose derivatives: an expedient approach to the synthesis of chiral benzoxazocine derivatives and tricyclic nucleosides

Pd-catalyzed intramolecular arylamination on sugar derivatives has been accomplished by using bulky biaryl phosphine ligands. An application of this methodology on a variety of D-glucose-derived substrates, 2a-f, led to the synthesis of highly functionalized cis-fused tricyclic oxazocines, 3a-e. The products could subsequently be transformed to the optically active benzoxazocine derivative 4 and tricyclic nucleoside 6. This is the first example of the synthesis of eight-membered rings via intramolecular cycloamination of furanose derivatives, which provides a very useful method for the catalytic synthesis of medium-ring heterocycles.     

Entanglement Potential Versus Negativity of Wigner Function for SUP-Operated Quantum States

We construct a distinct category of nonclassical quantum states by applying a superposition of products (SUP) of field annihilation (\(\hat {a}\)) and creation (\(\hat {a}^{\dagger }\)) operators of the type (\(s\hat {a}\hat {a}^{\dagger }+t\hat {a}^{\dagger }\hat {a}\)), with \(s^{2}+t^{2}=1\), upon thermal and even coherent states. We allow these SUP operated states to undergo a decoherence process and then describe the nonclassical features of the resulted field by using the entanglement potential (EP) and the negativity of the Wigner distribution function. Our analysis reveals that both the measures are reduced in the linear loss process. The partial negativity of the Wigner function disappears when losses exceed 50% but EP exists always.     

Charge state distribution studies of pure and oxygen mixed krypton ECR plasma – signature of isotope anomaly and gas mixing effect

We report the charge state distributions of the pure, 25% and 50% oxygen mixed krypton plasma to shed more light on the understanding of the gas mixing and the isotope anomaly [A. G. Drentje, Rev. Sci. Instrum. 63 (1992) 2875 and Y Kawai, D Meyer, A Nadzeyka, U Wolters and K Wiesemann, Plasma Sources Sci. Technol. 10 (2001) 451] in the electron cyclotron resonance (ECR) plasmas. The krypton plasma was produced using a 10 GHz all‐permanent‐magnet ECR ion source. The intensities of the highly abundant four isotopes, viz. ⁸²Kr (~11.58%), ⁸³Kr (~11.49%), ⁸⁴Kr (~57%) and ⁸⁶Kr (17.3%) up to ~ +14 charge state have been measured by extracting the ions from the plasma and analysing them in the mass and the energy using a large acceptance analyzer‐cum‐switching dipole magnet. The influence of the oxygen gas mixing on the isotopic krypton ion intensities is clearly evidenced beyond +9 charge state. With and without oxygen mixing, the charge state distribution of the krypton ECR plasma shows the isotope anomaly with unusual trends. The anomaly in the intensities of the isotopes having quite closer natural abundance, viz. ⁸²Kr, ⁸⁶Kr and ⁸³Kr, ⁸⁶Kr is prominent, whereas the intensity ratio of ⁸⁶Kr to ⁸⁴Kr shows a weak signature of it. The isotope anomaly tends to disappear with increasing oxygen mixing in the plasma. The observed trends in the intensities of the krypton isotopes do not follow the prediction of linear Landau wave damping in the plasma. Copyright © 2016 John Wiley & Sons, Ltd.     

Intercalation of octadecylamine into montmorillonite: molecular simulations and XRD analysis

Intercalation of octadecylamine (ODAMIN) into Na montmorillonite based on the ion-dipole interaction was investigated using molecular mechanics and molecular dynamics simulations combined with X-ray powder diffraction. Molecular modeling revealed the interlayer structure of the ODAMIN-montmorillonite intercalate, the charge distribution on the host layer and guest species, and the energy characteristics, i.e., the total sublimation energy and it's individual contributions (electrostatic and Van der Waals). The present study showed the development of the interlayer structure, basal spacing, and exfoliation energy in dependence on the ODAMIN content.     

Photoluminescent phenylated polyfluorenes synthesized in an organic solvent and supercritical carbon dioxide

A number of new phenylated polyfluorenes with blue emission are synthesized via the Diels-Alder reaction in chloronaphthalene and supercritical carbon dioxide. It is shown that these polymers are thermally stable. A comparative analysis of their properties shows that a ??green?? solvent is a suitable alternative to organic solvents for obtaining phenyl-substituted polyfluorenes via the Diels-Alder reaction.     

Recrystallization of natural chrysoberyl in multicomponent melts

Chrysoberyl and alexandrite crystals have been grown from solutions in melts based on the Li₂CO₃-MoO₃, Bi₂O₃-MoO₃, PbO-V₂O₅, Na₂B₄O₇, and K₂MoO₄-MoO₃ systems using natural alexandrite and chrysoberyl debris as the initial BeAl₂O₄ compound. An analysis of the morphology and homogeneity of the crystals grown has revealed the Bi₂O₃-MoO₃ solvent to be the most appropriate. The optimal color characteristics (??quality?? of alexandrite effect) manifest themselves when adding about 5 mol % Cr₂O₃. The largest crystals (up to 10 mm in size) were obtained from a solution in melt based on PbO-V₂O₅ at a ratio of the crystal-forming component to the solvent of 9: 91 wt %; These characteristics, along with a relatively low operating temperature (970°C), give grounds to consider this type of solvent promising.     

A new method of synthesis of the B<Subscript>3</Subscript>H<Stack><Subscript>8</Subscript><Superscript>−</Superscript></Stack> anion

A new method of synthesis of the B₃H₈⁻ anion has been suggested. The method uses the reaction of some metal halides (CuCl, SnCl₂, CrCl₃, PbF₂, PbCl₂, PbBr₂, and BiCl₃) with sodium tetrahydroborate. It is characterized by high (up to quantitative) yields and simplicity of isolation of the target products ((n-C₄H₉)₄N)[B₃H₈] and Cs[B₃H₈].     

Relativistic calculations of electronic excitation probabilities in U<Superscript>92+</Superscript>-U<Superscript>91+</Superscript>(1<Emphasis Type="Italic">s</Emphasis>) collisions in the monopole approximation

Heavy ion collisions U⁹²⁺-U⁹¹⁺(1s) at a 6 MeV incident particle energy per nucleon are considered. The wave function of the electron was determined by solving the Dirac time-dependent equation in a central field, which is the sum of the potential of the target nucleus and the potential of the incident nucleus taken in the monopole approximation. The Dirac equation was solved using the basis set of Hermitian B-splines. The probabilities of remaining in the 1s target state were calculated as functions of the impact parameter.     

Microtube Membranes for the Selective Synthesis of Oxygen and Hydrogen

Russian Journal of Electrochemistry - Abstract—The results on the gas permeability of oxygen- and hydrogen-permeable microtube membranes are shown. For oxygen-permeable microtube membranes of...