2,4-Pentanediolate as an alkoxide/diketonate "hybrid" ligand and the formation of aluminum and zirconium derivatives

When 2,4-pentanediol (2,4-H(2)pd) is deprotonated, the resulting dianion (2,4-pd) serves as a type of "hybrid" ligand, i.e., an alkoxide that possesses structural features of a β-diketonate. 2,4-Pentanediol reacts with Al(O-s-Bu)(3) and Zr(O-i-Pr)(4) to form chelated multinuclear complexes. The aluminum-containing product is first isolated as the insoluble [Al(2,4-pd)(2,4-Hpd)](n); on sublimation, a hydrocarbon-soluble mixture of polymetallic species is generated. Mass spectral evidence suggests that both Al(4)(2,4-pd)(6) and Al(5)(2,4-pd)(7)(2,4-Hpd) are present. The zirconium complex is isolated as an adduct, [Zr(2,4-pd)(2)](2)·(2,4-H(2)pd). The pentanediolates decompose on heating to form Al(2)O(3) and ZrO(2). Unlike the mononuclear Al(acac)(3) and Zr(acac)(4) derivatives (acac = acetylacetonate), the formation of aggregates with the 2,4-pd ligand suggests that the latter has more coordinative flexibility. The geometries of several model aluminum complexes with oxygen donor ligands were studied with density functional theory methods. The optimized structures were used with the gauge, including atomic orbital (GIAO) method to calculate their (27)Al NMR magnetic shielding values for comparison with experiment.     

Morphology of swift heavy ion tracks in metallic glasses

Swift heavy ion irradiated metallic glasses were studied using synchrotron based small angle X-ray scattering (SAXS). Ribbons of Fe₈₀B₂₀, Fe₈₅ B₁₅, Fe₈₁B_13.5Si_3.5C₂ and Fe₄₀Ni₄₀B₂₀ were irradiated with 11.1 MeV/nucleon (MeV/u) ¹³²Xe, ¹⁵²Sm, ¹⁹⁷Au and 8.2 MeV/u ²³⁸U ions to fluences between 1 × 10¹⁰ and 1 × 10¹² ions/cm². The SAXS measurements provide evidence for the formation of ion tracks and allow a quantitative analysis of the track ensemble in all studied materials. The ion tracks have been well described by cylinders with abrupt boundaries and an electronic density change of (0.03 ± 0.01)% between track and matrix material. An inelastic thermal spike model was fitted to the experimental track radii to determine the critical energy density required to create an ion track. Despite the similar energy loss and track cross-sections, 30% higher track creation threshold is apparent for the binary alloys.     

On <Emphasis Type="Italic">g</Emphasis>-functions for Laguerre function expansions of Hermite type

We examine weighted L ^p boundedness of g-functions based on semigroups related to multi-dimensional Laguerre function expansions of Hermite type. A technique of vector-valued Calderón–Zygmund operators is used.