Disk aromaticity of the planar and fluxional anionic boron clusters B20(-/2-)

The presence of excess electrons modifies the structural landscape and tends to extend the planarity of boron clusters. While the neutral B(20) is tubular, both the anion and dianion B(20)(-/2-) become planar. Geometrical features of the stable anions suggest the existence of a new type of cluster that is planar and doubly cyclic with one atom located at the center (see figure), as well as being fluxional.     

First Approach to Nitrogen‐Containing Fused Aromatic Hydrocarbons as Targets for Organoelectronics Utilizing a New Transformation of O‐Protected Diaryl Methanols

A new concise approach for the construction of heteroatom analogues of polycyclic aromatic benzo[g]quinoline, benzo[b]carbazole, and pyrido[b]carbazole systems via diaryl methanols is described. This transformation involves formation of a central benzene ring fused to two aromatic 5‐ or 6‐membered rings of pyrrole and/or pyridine by using a combination of two aromatic aldehydes, of which at least one contains a ring nitrogen. Analysis of the UV and fluorescent properties, Stokes shifts, quantum yields in solution, and π‐stacking interactions in the crystal structures of the new materials was performed. These polycyclic aromatic compounds show potential as small‐molecule organoelectronic materials.     

Fiber-shaped flexible solar cells

Flexible solar cells with the advantages of lightweight, foldability, and low cost, and extensive applications have attracted much academic interest and industrial attention during the last decades. The principles, development, and characteristics of various silicon based, CuInGaSe, dye-sensitized, and organic photovoltaic flexible solar cells are introduced and reviewed. Special emphasis gives different types of the newly and rapidly developed fiber-shaped solar cells and their characteristics. Compared with traditional ones, the fiber-shaped solar cells use flexible photoelectrodes prepared with low-cost metal wire, optical fibers, and carbon etc., not only greatly expanding their flexibility and decreasing cost, but evidently improving their various properties. At last as their further development, some prospective researches on mesh-like solar cells are introduced.     

Hexakis(4-phormylphenoxy)cyclotriphosphazene: X-ray and DFT-calculated structures

The crystal structure of hexakis(4-phormylphenoxy)cyclotriphosphazene is determined by using X-ray diffraction and then the molecular structure is investigated with density functional theory (DFT). X-Ray study shows that the title compound has C-H…π interaction with phosphazene ring. The molecules in the unit cell are packed with Van der Waals and dipole-dipole interactions and the molecules are packed in zigzag shaped. Optimized molecular geometry is calculated with DFT at B3LYP/6-311G(d,p) level. The results from both experimental and theoretical calculations are compared in this study.     

The Fine Spectra of the Difference Operator △ Over the Sequence Space bvp, （1 ≤ p 〈 ∞）^＊

The sequence space bvp consisting of all sequences （xk） such that （xk -xk-1） belongs to the space gp has recently been introduced by Basar and Altay [Ukrainian Math. J., 55（1）, 136-147（2003）]; where 1 ≤ p ≤ ∞. In the present paper, some results concerning with the continuous dual and f-dual, and the AD-property of the sequence space bvp have been given and the norm of the difference operator A acting on the sequence space bvp has been found. The fine spectrum with respect to the Goldberg＇s classification of the difference operator △ over the sequence space bvp has been determined, where 1≤p〈∞.     

Continuity of solution mappings in some parametric non-weak vector Ky Fan inequalities

This paper gives sufficient conditions for the continuity of the solution mappings of parametric non-weak vector Ky Fan inequality problems with moving cones. The main results of the paper are new and are obtained under an assumption different from the known density hypothesis. They are written in terms of nonlinear scalarization functions associated to the data of the problems under consideration. Verifiable conditions are given, and examples are provided.     

Ultrasonic frequencies correlated with the volume changes of the q[110] mode for the first-order phase transition in NH4CI

We correlate here by means of γ-Grüneisen relations the volume changes with the ultrasonic frequencies of the q[110] mode of NH₄Cl for the first-order phase transition in this crystal. The ultrasonic frequencies were calculated by a method, which we have developed, using the length-change data from the literature at pressures of 0, 0.2, 0.4 and 0.6 kbar in the first-order phase region of NH4Cl.

Our calculated frequencies are in very good agreement with the observed data from the literature for the q[11 0] mode at these pressures. This shows that by correlating the volume changes with the ultrasonic frequencies, the observed behaviour of NH₄Cl can be explained adequately near the first-order phase transition in this crystalline system.     

Flavothionato metal complexes: implications for the use of hydroxyflavothiones as green pesticides

Transition-metal complexes of 3-hydroxyflavothiones have been prepared and structurally characterized; the photochemical properties of these complexes have been examined and are discussed in the context of the use of these compounds as photodegradable pesticides.