[Co(amp)2Cl2]2[ZnCl4]体系中两对称异构体的2D NMR研究

The two symmetrical isomers in [Co(amp)₂Cl₂]₂[ZnCl₄](amp=2-(Aminomethyl)pyridine) system were syn-thesized by general oxidation method and were separated by chromatography and recrystallization method. Their configurations were assigned by using 2D NMR techniques, particularly the NOESY NMR spectra. Solvent used was Me₂SO-d₆ with the central peak of the CD₃ septet as the reference ( ₁₃C,δ 39.37; ₁H,δ 2.49 relative to SiMe₄). Cation exchange media used was Dowex 50Wx 2(H⁺ form, 200～400mesh; Biorad).     

Effects of Calcination on the Physical and Photocatalytic Properties of TiO<Subscript>2</Subscript> Powders Prepared by Sol–Gel Template Method

TiO₂ powders were prepared by sol–gel template method and calcined under different conditions. XRD, BET and TEM were used to characterize the TiO₂ powders obtained. The photocatalytic activity of TiO₂ was investigated by the degradation of methyl orange. It was found that TiO₂ powder has the highest photocatalytic activity at a calcination temperature of 673 K. The effects of physical properties such as surface area, crystallinity and crystal phase on the photocatalytic activity of TiO₂ were discussed.     

Alternating copolymers consisting of arylalkyl methacrylates. I. Fluorescence properties of poly(arylalkyl methacrylate-alt-styrene) in organic solution

Alternating and random copolymers of 9-phenanthrylmethyl methacrylate or 2-(9-carbazolyl)ethyl methacrylate with styrene were synthesized and their fluorescence properties were examined. There was no noticeable difference in the spectral features of the alternating and random copolymers in tetrahydrofuran (THF), demonstrating that this type of polymers have no quenching sites in the polymer chains. The fluorescence quenching studies indicated that the alternating copolymers permitted singlet-state energy migration as efficiently as the corresponding random copolymers but less efficiently than the random copolymers with higher chromophore contents. These results strongly suggest that to be chromophores close to each other is most important for facilitation of an intramolecular energy migration. © 1995 John Wiley & Sons, Inc.     

Separation of structural isomers using cyclodextrin-polymers coated on silica beads

Summary Several -cyclodextrin (CD)-bonded stationary phases for high performance liquid chromatography (HPLC) were prepared, based on silica beads coated with a poly(alkylamine), [poly(ethyleneimine)(PEI)]. In order to obtain stationary phases with a high content of CD and maximum accessibility of the CD cavity, the functionalization was carried out after the coating, using the mono-tosyl derivative of CD as the intermediate. The ability of these supports to separate ortho, meta and para isomers of some disubstituted benzene derivatives was examined. The contribution of the amino groups of the polymer and of the CD cavity to the separation process is discussed. The resolution is mainly based on the difference in the stability of the complexes of the various isomers with CD. The influence of the amount of CD on the height of the theoretical plate is also studied.     

羟丙基甲基纤维素作为水泥添加剂研究(四)

以萘磺酸甲醛缩合物为分散剂，水溶性羟丙基甲基纤维素衍生物为粘稠剂，研究了它们的混合物对混凝土材料的分散性与粘稠性及其它性能的影响，并探索了其作用机理。     

氨基酚异构体的离子对反相液相色谱分析的研究

本文研究了离子对反相液相色谱分析氨基酚异构体的可能性、影响因素和色谱条件，发现以含４×１０－８ｍｏｌ／Ｌ四丁基碘化铵、０．１８４ｍｏｌ／Ｌ醋酸钠的甲醇水溶液（２３：７７）作为流动相，ＯＤＳ为固定相时可以实现氨基酚异构体的良好分离。     

Phosphorescence lifetime of naphthalene and phenanthrene in aggregated aromatic molecule-β-cyclodextrin-precipitant complexes

Aggregated aromatic molecule--cyclodextrin-precipitant complexes exhibit long-lived phosphorescence at room temperature in water after the chemical binding of oxygen. The temperature dependences of the phosphorescence lifetimes of naphthalene-h₈, naphthalene-de, and phenanthrene in the aggregates were measured. For example, the phosphorescence lifetimes of naphthalene-d₈ aggregated with -cyclodextrin and cyclohexane are equal to 25.1, 17.6, and 6.8 s at 77, 276, and 347 K, respectively, and that of phenanthrene aggregated with isooctane and -cyclodextrin are 3.24, 3.06, and 1.26 s at 268, 274, and 335 K, respectively. The temperature dependences of the phosphorescence lifetimes at room temperature are determined by the rate constants of the radiative and nonradiative transitions from the triplet state of an aromatic molecule.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2225–2228, September, 1996.     

长链烷基苯异构体的气相色谱研究

长链烷基苯异构体的分离分析是石油化学中一个重要课题,曾有较多作者用气相色谱方法研究了长链烷基苯的分离及不同碳数的