Destabilizing the Dehydrogenation Thermodynamics of Magnesium Hydride by Utilizing the Immiscibility of Mn with Mg.

Hydrogen storage is a key technology for the advancement of hydrogen and fuel cell power technologies in stationary and portable applications. MgH, an example of a high-capacity hydrogen storage material, has two major material challenges for practical applications: slow hydrogen desorption kinetics and high hydrogen desorption temperature. Numerous studies have reported enhancements in kinetics but only a few in thermodynamics.

Structural Variation of Self-Organized Mg Hydride Nanoclusters in Immiscible Ti Matrix by Hydrogenation.

Hydrogenation of nonequilibrium alloys may form nanometer-sized metal hydride clusters, depending on the alloy compositions and hydrogenation conditions. Here in the Ti-rich compositions of the immiscible Mg-Ti system MgH clusters are embedded in a Ti-H matrix. Our previous works have indicated that the interface energy between the two metal hydrides reduces the stability of MgH.

Spin diffusion and H spin-lattice relaxation in Cs(HSO)(HPO) containing a small amount of ammonium ions.

Inorganic solid acid salts with hydrogen bond networks frequently show very long spin-lattice relaxation times even for H because the hydrogen bonds suppress motions. In the present work, the H spin-lattice relaxation in Cs(HSO)(HPO) containing a small amount of ammonium ions were studied in detail by use of the effect of magic angle spinning (MAS) on the relaxation. The H spin-lattice relaxation times of the acid protons decrease with increase in the content of ammonium ions.

Multifunctional Octamethyltetrasila[2.2]cyclophanes: Conformational Variations, Circularly Polarized Luminescence, and Organic Electroluminescence.

Both symmetrical and unsymmetrical cyclophanes containing disilane units, tetrasila[2.2]cyclophanes 1-9, were synthesized. The syn and anti conformations and the kinetics of inversion between two anti-isomers were investigated by X-ray diffraction and variable-temperature NMR analysis, respectively.

Detailed mechanisms of H spin-lattice relaxation in ammonium dihydrogen phosphate confirmed by magic angle spinning.

Mechanisms of the H spin-lattice relaxation in NHHPO were studied in detail by use of the effect of magic angle spinning on the relaxation. The acid and the ammonium protons have different relaxation times at the spinning rates higher than 10 kHz due to suppression of spin diffusion between the two kinds of protons. The intrinsic relaxation times not affected by the spin diffusion and the spin-diffusion assisted relaxation times were evaluated separately, taking into consideration temperature dependence.

Structural changes of layered alkylsiloxanes during the reversible melting-solidification process.

Through various in situ analyses, we have revealed the structural changes that occur during the reversible melting-solidification process of layered alkylsiloxanes (CnLSiloxanes) with carbon numbers (n) of 18 and 16. In situ high-resolution solid-state (13)C nuclear magnetic resonance (NMR) analysis at controlled temperatures indicates drastic conformational changes of the long alkyl chains during the melting-solidification process. A (13)C NMR signal at 33 ppm, which shows the highest intensity at room temperature (RT), is assigned to an inner methylene group with an all-trans conformation.