Crystal structure, dissolution, and deposition of a 5 nm functionalized metal-organic great rhombicuboctahedron

A metal-organic great rhombicuboctahedron (termed MOP-18) was functionalized with extended alkyl chains and crystallized. It has 12 rigid square-shaped Cu2(CO2)4 paddle-wheel building units and 24 5-dodecoxybenzene-1,3-dicarboxylate links. MOP-18 is soluble in a variety of organic solvents, such as tetrahydrofuran, chloroform, and toluene, which enabled its assembly on graphite substrate and its observation by scanning tunneling microscopy.     

Effects of surfactant and salt concentrations on capillary flow and its entry flow for wormlike micelle solutions

Dynamic viscoelasticities and flow properties were measured for aqueous solutions of cetyltrimethylammonium bromide (CTAB) and sodium salicylate (NaSal) to examine the effects of surfactant (C _D) and salt (C _S). The relaxation time λ of a single mode Maxwell model was obtained, and the relationship between λ and free NaSal concentration was discussed. The relation between λ and was applied to the classification of flow curves, which were obtained using a capillary rheometer. In the flow curves, a shear rate jump occurred at low shear rates for the solutions with low , while bending was seen at high shear rates for all the flow curves. On the other hand, vortex growth at the salient corner in the entrance region of the capillary was also investigated. Four different flow patterns were identified: Newtonian-like flow (A), steady vortex flow (B), periodically oscillated flow (C), and perfectly unstable flow (D). In the steady vortex of the flow pattern B, the vortex length increased with increasing shear rate. In the flow patterns C and D, white turbidity was observed. Furthermore, the relation between λ and was also applied to the discussion on the development of the vortex.     

Hopping conductivity of distorted K2NiF4-type (Ca1+xNd1−x)CrO4

Orthorhombic distorted K₂NiF₄-type (Ca_1+xNd_1?x)CrO₄ (0.00 ≤ x ≤ 0.15) was synthesized using a standard ceramic technique. The cell parameters (a and c) decreased, whereas the cell parameter (b) increased with the increase in x. The variation in the global instability index (GII) indicated that the crystal stability of (Ca_1+xNd_1?x)CrO₄ was not influenced by the Cr⁴⁺ ion content. At all temperatures, the electrical conductivity (σ) of (Ca_1+xNd_1?x)CrO₄ increased with the increase in x. (Ca_1+xNd_1?x)CrO₄ was a p-type semiconductor and exhibited hopping conductivity in a small-polaron model in the temperature range of 290 K ≤ T ≤ 713 K. The Cr⁴⁺ ion acts as an acceptor, and the electron transfer through the Cr³⁺–O–Cr⁴⁺ path becomes active as a result of the Cr⁴⁺ ion content and the Cr–O(1) distance.     

Fission of metal clusters: A comparison of jellium model calculations and shell correction method calculations

We investigate the fission process Ag²⁺₂₃ → Ag⁺₁₂ + Ag⁺₁₁ in order to compare total energies that calculated by the shell correction method and jellium models. A cavity potential and a Woods-Saxon-type potential are used as the shell potential for the shell correction method, with which the single-particle energy levels are calculated. Shell corrections are obtained by using the Balian-Bloch formula and by smoothing the discrete energy levels in the shell potentials. The jellium model calculations are performed in the framework of the local spin density functional approximation. The conventional jellium model and stabilized jellium model are used. Although the qualitative agreement between the shell correction method calculations and the stabilized jellium calculations is very good, an improvement of the liquid drop energy will be necessary for the satisfactory quantitative agreement. © 1996 John Wiley & Sons, Inc.     

Robust Spirobifluorene Core Based Hole Transporters with High Mobility for Long-Life Green Phosphorescent Organic Light-Emitting Devices

Using a tailored high triplet energy hole transport layer (HTL) is a suitable way to improve the efficiency and extend the lifetime of organic light-emitting devices (OLEDs), which can use all molecular excitons of singlets and triplets. In this study, dibenzofuran (DBF)-end-capped and spirobifluorene (SBF) core-based HTLs referred as TDBFSBF1 and TDBFSBF2 were effectively developed. TDBFSBF1 exhibited a high glass transition temperature of 178 °C and triplet energy of 2.5 eV. Moreover, a high external quantum efficiency of 22.0 %, long operational lifetime at 50 % of the initial luminance of 89,000 h, and low driving voltage at 1000 cd m⁻² of 2.95 V were achieved in green phosphorescent OLEDs using TDBFSBF1 . Further, a high-hole mobility μ_h value of 1.9×10⁻³ cm² V⁻¹ s⁻¹ was recorded in TDBFSBF2 . A multiscale simulation successfully reproduced the experimental μ_h values and indicated that the reorganization energy was the primary factor in determining the mobility differences among these SBF core based HTLs.     

ChemInform Abstract: High‐Pressure Synthesis of Yb2Cu2In and Its Physical Properties.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.