Analytical utility of valence band X-ray photoelectron spectroscopy of iron and its oxides,with spectral interpretation by cluster and band structure calculations

The valence band and core-level X-ray photoelectron spectroscopy (XPS) of iron and its oxides are reported, and the valence band spectra interpreted by various calculation models. The paper focuses upon the valence band region, which shows significant differences between the metal and the following oxidized iron species: FeO, Fe(3)O(4), alpha-Fe(2)O(3), gamma-Fe(2)O(3), alpha-FeOOH and gamma-FeOOH. The core region is of little analytical value as a means of distinguishing between these species, but the valence band region shows significant differences. These differences are consistent with spectra predicted by cluster and band structure calculations. Cluster calculations are valuable as a means for interpreting the spectra of iron oxides with multiple iron sites and defect characteristics.     

均相催化(中)

1,3-二烯烃的齐聚本章将讨论过渡会属催化反应机理的研究方法,并以1,3-二烯烃的镍和钯的络合物作为催化剂为例,如丁二烯的环化三聚、丁二烯的环化二聚和丁二烯与甲醇的调聚。机理研究至少要依据三个方面的信息: 1.产物分析不仅要根据其组成,而且要考虑产物的立体化学。 2,动力学数据由此可提供催化循环中反应速度控制步骤的信息。但是,在均相催化中,反应物(如烯烃)往往与金属有轻度的络合。 3.模型络合物的研究模型络合物应该要和有关的催化反应具有同样的     

N-(17-Phosphonooxylinolenoyl)glutamine and N-(17-phosphonooxylinoleoyl)glutamine from insect gut: the first backbone-phosphorylated fatty acid derivatives in nature

N-(17-Phosphonooxylinolenoyl)glutamine (1) and N-(17-phosphonooxylinoleoyl)glutamine (2) were isolated from the regurgitate of Spodoptora exigua and identified as the first natural alkyl chain-phosphorylated fatty acid derivatives. The compounds were characterized by HPLC-MS/MS and the assigned structures confirmed by synthesis via a dissymmetric bis-Wittig approach as the key reaction. Rearing of the larvae on a diet enriched with inorganic phosphate increased the amount of the phosphorylated N-acyl glutamines in the regurgitate.