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Impregnation of hyper-cross-linked polystyrene (HPS) by either Co 2 (CO) 8 in 2-propanol or the [Co(DMF) 6 ] 2+ [Co(CO) 4 ] -2 complex in dimethylformamide (DMF), followed by thermolysis at 200 °C, results in the formation of discrete Co nanoparticles. The concentration and characteristics of such nanoparticles were investigated by X-ray fluorescence (XRF) spectroscopy, ferromagnetic resonance (FMR) spectroscopy, and transmission electron microscopy (TEM). The FMR data here confirm the formation of spherical nanoparticles. At relatively low concentrations of Co, the magnitude of the FMR line width reveals that the mean Co nanoparticle diameter is about 2 nm, which agrees closely with the mean particle diameter discerned by TEM. An increase in Co content higher than 8 wt % is accompanied by an increase in mean particle diameter due to an increase in the population of large Co nanoparticles up to 15 nm across. Regulated nanoparticle growth over a wide range of Co concentrations is attributed to nanoscale HPS cavities, which serve to physically restrict the size of growing particles.

New chiral P,N-hybrid aryl phosphites have been obtained by one-step phosphorylation of amino and imino alcohols. Complexation of the new ligands with [Rh(CO) 2 Cl] 2 , [Pd(COD)Cl 2 ] and [Pd(allyl)Cl] 2 was found to give chelate complexes [Rh(CO)Cl(η 2 -P ʝ N)], [PdCl 2 (η 2 -P ʝ N)] and [Pd-(allyl)(η 2 -P ʝ N)] + Cl − , respectively. With these new P,N-ligands, up to 82% ee enantioselectivity was achieved in the [a] The new P,N-bidentate aryl phosphites were synthesized by one-step phosphorylation of the corresponding amino and imino alcohols with bis(2,6-dimethylphenyl) chlorophosphite.They divide into two groups: ligands 3aϪ3f, possessing sp 3 -hybridized nitrogen atoms, and ligands 3gϪ3m, which have sp 2 -hybridized nitrogen atoms. All the compounds 3aϪm are soluble in conventional organic solvents and stable under dry conditions for several months. On treatment with [Rh(CO) 2 Cl] 2 , their neutral carbonyl(chloro)Rh I complexes were obtained.The ν(CO) and 1 J P,Rh parameters in their IR and 31 P NMR spectra act as sensitive indicators, which characterise the mode of complexation of the P,N-ligands and allow the π-acceptor ability of the phosphorus centre and the degree of electronic non-symmetry of the ligands to be estimated. [13Ϫ15] In general, ligands 3aϪ3m give chelate complexes. Thus, the

SummaryThrough a straightforward mathematical derivation it is shown that the compressibility correction factor equals the ratio of gas pressure at the column outlet to the average pressure in the column, j = po/p. Therefore, by multiplying by this factor, the experimentally measured retention volumes can be recalculated to the average pressure in the column. Corrected retention volumes thus represent the volume of the mobile phase under real conditions of chromatography in the column. Appropriate definitions for corrected retention volumes and factor ] are formulated. the pressure drop that matters, but the absolute value of the pressure.Without having said in plain words what is wrong with the retention volumes measured experimentally at the column outlet and why and in what direction these values have to be corrected, Ettre and Hinshaw present a detailed derivation of the compressibility correction factor. In these complicated mathematical exercises, it escaped the attention of the authors that the crucial steps in the derivation are integrations of functions (written for the gas flow rate or any other gradually changing quantity) along the column from the pressure Pi at the column inlet to pressure Po at the outlet. These integrations do not resemble any extrapolation to a hypothetical case of zero pressure drop. Instead, the mathematical meaning of the integration within a definite range of pressures is that it is replacing a gradually changing value of pressure by an equivalent, value, averaged over this range.

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