Hellmut Eckert

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Metaphosphate glasses with two monovalent species A(1-x)B(x)PO3 (0 ≤x≤ 1) show mixed-ion effects (MIE) in the dc conductivities and glass transition temperatures, which are strongly dependent on the cation size mismatch between the two mobile species. In the present contribution, mixed-ion metaphosphate glasses based on the cation combinations Cs-Li, Rb-Li,(More)
Anisotropic interactions present in three new nitroxide radicals prepared by N,N addition of NO to various borane-phosphane frustrated Lewis pairs (FLPs) have been characterized by continuous-wave (cw) and pulsed X-band EPR spectroscopies in solid FLP-hydroxylamine matrices at 100 K. Anisotropic g-tensor values and (11)B, (14)N, and (31)P hyperfine coupling(More)
An experimental strategy has been developed for measuring multiple dipole-dipole interactions in inorganic compounds using the technique of rotational echo double resonance (REDOR) NMR. Geometry-independent information about the dipole couplings between the observe nuclear species S (arbitrary quantum number) and the heteronuclear species I (spin-12) can be(More)
Semiconductors are key materials in modern electronics and are widely used to build, for instance, transistors in integrated circuits as well as thermoelectric materials for energy conversion, and there is a tremendous interest in the development and improvement of novel materials and technologies to increase the performance of electronic devices and(More)
– Modulated Scanning Calorimetry shows the non-reversing heat flow near Tg to display a sharply defined global minimum in the 0.28 < x < 0.40 range, identified with the selforganized phase (SOP) of titled glasses. P NMR, Raman scattering and constraint counting algorithms suggest this phase to consist of two distinct global morphologies; a Se-rich backbone(More)
'H wideline and magic angle spinning (MAS) NMR results are reported for water in a series of synthetic and naturally occurring silicate glasses containing from 0.04 to 9.4 wt % H20. For glasses free of paramagnetic metal ions, the absolute water contents can be accurately determined by a solid echo IH NMR technique with pyrophyllite, A12Si,010(OH)2, as an(More)
Hydroboration of dimesitylnorbornenylphosphane with Piers' borane [HB(C6F5)2] gave the frustrated Lewis pair (FLP) 4 in good yield. It has the -PMes2 Lewis base attached at the 2-endo position and the -B(C6F5)2 group 3-exo oriented at the norbornane framework. The vicinal FLP 4 was shown by X-ray diffraction and by spectroscopy to be a rare example of an(More)
Insights into the structure and dynamics of the binary As-Se glass system have been obtained from high-temperature Se NMR studies of molten samples. In materials having As contents < 20 at.%, dynamic exchange averaging processes are detected and analysed quantitatively by detailed lineshape simulations. At high temperatures (1.5⋅melting Temperature), only a(More)
The crystallization mechanism of a high-strength lithium disilicate glass-ceramic in the SiO(2)-Li(2)O-P(2)O(5)-Al(2)O(3)-K(2)O-(ZrO(2)) system, used as restorative dentistry material, has been examined on the basis of quantitative (29)Si magic angle spinning (MAS) and (29)Si{(7)Li} rotational echo double resonance (REDOR) NMR spectroscopy. Crystallization(More)