Phase behavior of binary mixtures of tetraglyme (G4) and Mg­[TFSA]2 (TFSA: bis­(trifluoro­methane­sulfonyl)­amide) was investigated. In a 1:1 molar ratio, G4 and Mg­[TFSA]2 formed a stable complex with a melting point of 137 °C. X-ray crystallography of a single crystal of the complex grown from a G4-Mg­[TFSA]2 binary mixture revealed that the G4 molecule wraps around Mg2+ to form a complex [Mg­(G4)]2+ cation, and the two [TFSA]− anions also participate in the Mg2+ coordination in the crystal. The thermal stability of [Mg­(G4)]­[TFSA]2 was examined by thermogravimetry, and it was found that the complex is stable up to 250 °C. Above 250 °C, desolvation of the Mg2+ ion takes place and G4 evaporates. On the other hand, the weight loss starts at around 140 °C in solutions containing excess G4 (n > 1 in Mg­[TFSA]2:G4 = 1:n) due to the evaporation of free (uncoordinated) G4. The suppression of G4 volatility in the [Mg­(G4)]­[TFSA]2 complex is attributed to strong electrostatic and induction interactions between divalent Mg2+ and G4. In addition, complexation of G4 with Mg2+ is effective in enhancing the oxidative stability of G4. Linear sweep voltammetry revealed that the oxidative decomposition of [Mg­(G4)]­[TFSA]2 occurs at electrode potentials >5 V vs Li/Li+, while the oxidation of uncoordinated G4 occurs at around 4.0 V. This oxidative stability enhancement occurs because the HOMO energy level of G4 is reduced by complexation with Mg2+, which is supported by the ab initio calculations.

sion couples of pure aluminum and copper metals.In the aluminum-copper equilibrium phase diagram there are five intermediate phases in this temperature range, namelyIt appears that the layer growth of each phase is controlled by the process of volume diffusion since the rate of layer growth obeys the parabolic law. From the temperature dependency of the rate constants of layer growth, the activation energies of the individual phases were obtained.The interdiffusion coefficient for each intermediate phase was calculated by the method introduced by Heumann, andAluminum oxide powder was used for the measurement of the Kirkendall effect. It is clear from this measurement that diffusion in the multilayer system is controlled by the vacancy mechanism and that aluminum diffuses more rapidly than copper.

It is demonstrated that electronic structure calculations using the local-density approximation with density-functional theory accounts for the distinctly different behaviors in the equilibrium phase diagrams among Cu-Ag, Cu-Au, and Ag-Au alloy systems. A detailed microscopic analysis is made based on the prescription proposed by Connolly and Williams.

Interdiffusion in the aluminum-magnesium system was investigated in the temperature range of diffusion couples of pure aluminum and magnesium.Electron probe micro-line analysis of specimens indicated that two intermediate phases, namely the diffusion zone. It is concluded that the growth of each phase is controlled by the process of volume diffusion since the rate of layer growth obeys the parabolic law.The activation energies for the interdiffusion in phases estimated from the temperature dependence of the interdiffusion coefficients calculated by Heumann's method were 13.6 and 28.1kcal/mol, respectively. The Kirkendall effect was measured with a marker. The marker shifted to the aluminum side with respect to Matano's interface. The result is opposed to that reported by Heumann and Kottmann who stated on the basis of Bungardt's experimental study that the initial interface moves to the magnesium side with respect to Matano's interface. The measurement of the Kirkendall effect showed that the diffusion in this system was controlled by a vacancy mechanism and that aluminum diffuses more rapidly than magnesium.

Preparation of Z-Ala-OCH3. To a solution of N-(benzyloxycarbonyl) alanine (447 mg, 2.0 mmol) and triethylamine (213 mg, 2.1 mmol) in methylene chloride (6 mL) at 0 °C was added methyl chloroformate (190 mg, 2.0 mmol). After 10 min of stirring at 0 °C, DMAP (23 mg, 0.2 mmol) was added and the resulting solution was stirred at 0 °C for 15 min. The reaction mixture was diluted with methylene chloride (40 mL) and washed with saturated NaHC03 (20 mL), 0.1 M HC1 (10 mL), and saturated NaCl (30 mL). The aqueous layers were extracted with methylene chloride (20 mL). The combined extracts were dried over anhydrous MgS04 and evaporated to dryness. The residue was subjected to silica gel column chromatography with methylene chloride as an eluant to yield pure Z-Ala-OCH3 (455 mg, 96%):