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We present detailed calculations of the diffraction pattern of a powder of bundles of C 60 peapods.The influence of all pertinent structural parameters of the bundles on the diffraction diagram is discussed, which should lead to a better interpretation of X-ray and neutron diffraction diagrams. We illustrate our formalism for X-ray scattering experiments performed on peapod samples synthesized from 2 different technics, which present different structural parameters. We propose and test different criteria to solve the difficult problem of the filling rate determination.

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We report on successful preparation of Er 3+ doped transparent alumina (0.1-0.17 at. %) exhibiting visible light photoluminescence using wet shaping method and hot isostatic pressing. The effects of dopant amount, type of doping powder and powder pre-treatment on final microstructure, real in-line transmittance and photoluminescence characteristics were studied.The real in-line transmittance ranged between 28-56 %, depending on processing parameters.The transparency decreased with increased amount of dopant. The decrease is dependent on the type of doping powder and its pre-treatment.The photoluminescence spectra measured in both visible and NIR region showed typical emission bands due to the presence of Er 3+ ions. The decay profiles of the 4 S3/2→ 4 I15/2 transition were fitted with a 2-exponential function, with faster component in the range of 360-700 ns and slower component around 1.6-2.4 μs. The intensity of emissions and lifetime of the 4 S3/2 level decrease significantly with increasing concentration of Er 3+ ions.

Several unsymmetrically substituted salen‐type cobalt(II) Schiff‐base complexes CoL [H2L = 1,6‐bis(2‐hydroxyphenyl)‐3,3‐dimethyl‐2,5‐diaza‐1,5‐hexadiene (1); 1,6‐bis(2‐hydroxyphenyl)‐3,3‐dimethyl‐2,5‐diaza‐1,5‐heptadiene (2); 1‐(3‐tert‐butyl‐2‐hydroxy‐5‐methylphenyl)‐6‐(2‐hydroxyphen‐yl)‐3,3‐dimethyl‐2,5‐diaza‐1,5‐heptadiene (3); 1‐(2‐hydroxyphenyl)‐6‐methyl‐2,5‐diaza‐1,5‐nonadien‐8‐one (4); 1‐(3‐tert‐butyl‐2‐hydroxy‐5‐methylphenyl)‐6‐methyl‐2,5‐di‐aza‐1,5‐nonadien‐8‐one (5); 1‐(2‐hydroxyphenyl)‐3,3,6‐trimethyl‐2,5‐diaza‐1,5‐nonadien‐8‐one (6); 1‐(3‐tert‐butyl‐2‐hydroxy‐5‐methylphenyl)‐3,3,6‐trimethyl‐2,5‐diaza‐1,5‐nonadien‐8‐one (7)] were prepared and characterized by their UV/Vis absorption spectra, magnetic moments, and oxidation potentials. Except for complex 4 (irreversible oxidation with t½ ≈ 3 h), complexes 1–3 and 5–7 are remarkably resistant against irreversible auto‐oxidation in air‐saturated N,N‐dimethylformamide (DMF) at ambient temperature. To characterize the Lewis acidity of the cobalt center in 1–7, the equilibrium constant Kpy was determined for monoadduct formation with pyridine (CoL + pyCoL·py). An O2‐sensitive optode was used to determine the Henry constant, KH, for the system O2/DMF in the temperature range 298–228 K. The formation of 1:1 adducts of complexes 1–7 with O2 in DMF, as characterized by the equilibrium constant K O 2, was followed spectrophotometrically in the temperature range 298–228 K. The parameters ΔHo, ΔSo, and K O 2 are reported. At 298 K, K O 2 ranges from 21.9 M–1 (5) to 155 M–1 (7). The overall spectroscopic information, including EPR spectra obtained with frozen solutions of 3 and 7 in O2‐saturated DMF, confirm that the 1:1 adducts CoL·O2 are cobalt(III) superoxo compounds. The symmetrically substituted salen complex8 [H2L = 1,6‐bis(3‐tert‐butyl‐2‐hydroxy‐5‐methylphenyl)‐3,3,4,4‐tetramethyl‐2,5‐diaza‐1,5‐hexadiene in 8] is shown to catalyze the oxidation of triphenylphosphane and 2,6‐di‐tert‐butylphenol by O2 in DMF at ambient temperature. The correlation of the data obtained for K O 2, Kpy, and the oxidation potential E½ is discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

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The Eu 3+-doped transparent aluminas were prepared by wet shaping technique followed by pressure-less sintering and hot isostatic pressing. The effect of dopant amount on microstructure, real in-line transmission (RIT), photoluminescence (PL) properties, hardness and fracture behaviour was studied. The RIT decreased with increasing amount of the dopant. The PL emission spectra of Al2O3:Eu 3+ ceramics exhibited predominant red light emission with the highest intensity (under 394 nm excitation) for material containing 0.125 at.% of Eu 3+ and colour coordinates (0.645, 0.355) comparable with commercial red phosphors. The doping resulted in hardness increase from 26.1 GPa for undoped alumina to 27.6 GPa for Eu-doped sample. The study of fracture surfaces showed predominantly intergranular crack propagation micro-mechanism.