三个稀土-主族三金属Ln(III)-Sr(II)-K(I)配合物的结构与发光性质

用2,4,6-吡啶三甲酸和稀土钐、镝或钆的高氯酸盐溶液、碳酸锶、碳酸钾在180℃水热条件下进行反应,制备出3个含有3种金属离子的配位聚合物[LnSrK（ptc）₂（H₂O）]_n（Ln=Sm（1）、Dy（2）、Gd（3）,H₃ptc=2,4,6-吡啶三甲酸）。X射线单晶衍射分析表明三者具有相同的结构,属三斜晶系,P1空间群。配合物中配体2,4,6-吡啶三甲酸根以2种不同的配位方式与3种金属离子配位,一种方式中连接了7个金属离子,另一种方式中连接了8个金属离子。Ln（Ⅲ）为八配位,与羧基上的6个氧原子和2个吡啶环上的2个氮原子配位;Sr（Ⅱ）也是八配位,配位原子均为氧原子;K（I）与5个氧原子配位。荧光发射光谱表明,钐和镝的配合物在紫外光激发下均发射Sm（Ⅲ）和Dy（Ⅲ）两种离子的特征荧光,钆的配合物在紫外光激发下由于发生荷移跃迁而发射绿色荧光。     

经Opuntia dilenii haw植物提取液绿色合成制备的纳米铝酸锌的催化性质(英文)

Various nanosized zinc aluminate(ZnAl2O4) samples were prepared by a conventional and a mi- crowave method both with and without using Opuntia dilenii haw plant extract,and were charac- terized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),high resolution scanning electron microscopy(HRSEM),energy dispersion scanning(EDX),temperature dependent conductance measurements, thermoelectric power measurements, ultraviolet-visible (UV-Vis) diffuse reflectance spectroscopy,and photoluminescence spectroscopy.The formation of a pure ZnAl2O4 phase was confirmed by XRD and FT-IR.A change in morphology from nanosized plates to nanosized sheets with,respectively,the conventional and microwave heating methods was clearly shown by HRSEM.UV-Vis diffusion reflectance spectroscopy measured the band gaps of ZnAl2O4 nanosized plates and nanosized sheets as 3.5 and 3.9 eV,respectively.The synthesized ZnAl2O4 was single crystalline and has three photoluminescence emissions at 482,528,and 540 nm.ZnAl2O4 nanosized sheets prepared by the microwave method showed higher catalytic activity for the oxida- tion of benzyl alcohol(85% conversion) than ZnAl2O4 nanosized plates prepared by the convention- al method(60% conversion).     

Synthesis, Characterization, Spectroscopy and Study of Antimicrobial Properties of Two New Substituted Trichloroaluminate（Ⅲ） Complexes [AlCl3X]- （X = SCN-, CN-）

The synthesis and characterization of two new aluminate(Ⅲ) complexes with general formula K[AlCl3X] are reported. These compounds derived from aluminate trichloride and related salts. Potassium trichlorothiocyanoaluminate, PCTA, and potassium trichlorocyanatoalu-minate, PCCA, are two new ionic aluminate complexes. They can be easily synthesized in a nearly quantitative yield by using the direct reaction of AlCl3 and KX. The complexes were characterized by physico-chemical and spectroscopic methods. Theoretical calculations have been used for the extraction of structural and spectroscopic data of these new synthesized complexes. The antibacterial activities of such compounds were studied against the Staphylococcus aureus, Escherichia coli, Staphylococcus Epidermidis, Estreptococo B and Shigella.     

ZnAl2O4 SiO2纳米复合催化剂用于无溶剂条件下乙酸酐与醇、酚和胺的乙酰化反应简

A ZnAl₂O₄@SiO₂ nanocomposite was prepared from metal nitrates and tetraethyl orthosilicate by the sol-gel process, and characterized by X-ray diffraction, Fourier transform infrared, transmission electron microscopy, and N₂ adsorption-desorption measurements. The nanocomposite was tested as a heterogeneous catalyst for the acetylation of alcohols, phenols, and amines under solvent-free conditions. Under optimized conditions, efficient acetylation of these substrates with acetic anhydride over the ZnAl₂O₄@SiO₂ nanocomposite was obtained. Acetylation of anilines and primary aliphatic amines proceeded rapidly at room temperature, while the reaction time was longer for the acetylation of alcohols and phenols, showing that an amine NH₂ group can be selectively acetylated in the presence of alcoholic or phenolic OH groups. The catalyst can be reused without obvious loss of catalytic activity. The catalytic activity of the ZnAl₂O₄@SiO₂ nanocomposite was higher than that of pure ZnAl₂O₄. The method gives high yields, and is clean, cost effective, compatible with substrates having other functional groups and it is suitable for practical organic synthesis.     

ZnAl_2O_4@SiO_2纳米复合催化剂用于无溶剂条件下乙酸酐与醇、酚和胺的乙酰化反应(英文)

A ZnAl2O4@SiO2 nanocomposite was prepared from metal nitrates and tetraethyl orthosilicate by the sol-gel process,and characterized by X-ray diffraction,Fourier transform infrared,transmission electron microscopy,and N2 adsorption-desorption measurements.The nanocomposite was tested as a heterogeneous catalyst for the acetylation of alcohols,phenols,and amines under solvent-free conditions.Under optimized conditions,efficient acetylation of these substrates with acetic anhydride over the ZnAl2O4@SiO2 nanocomposite was obtained.Acetylation of anilines and primary aliphatic amines proceeded rapidly at room temperature,while the reaction time was longer for the acetylation of alcohols and phenols,showing that an amine NH2 group can be selectively acetylated in the presence of alcoholic or phenolic OH groups.The catalyst can be reused without obvious loss of catalytic activity.The catalytic activity of the ZnAl2O4@SiO2 nanocomposite was higher than that of pure ZnAl2O4.The method gives high yields,and is clean,cost effective,compatible with substrates having other functional groups and it is suitable for practical organic synthesis.     

钛酸锶光催化剂的改性研究进展

钛酸锶（SrTiO3）光催化剂是一种钙钛矿型三元氧化物,具有较强的氧化还原能力、良好的物理化学稳定性及环境友好等特点,在光催化各领域得到了广泛应用,如制氢/降解/光电催化等。SrTiO3对太阳光的利用率较低,且其本征光催化活性受光生载流子分离效率等因素限制,阻碍了实际应用。针对以上问题,将围绕国内外SrTiO3改性研究的现状进行综述,主要从掺杂、负载、复合改性等方面进行陈述。最后,对高效稳定SrTiO3光催化剂的未来发展趋势进行展望。     

Magnetic properties of La-Co substituted M-type strontium hexaferrites prepared by polymerizable complex method

Magnetic properties of La-Co substituted M-type strontium hexaferrites were studied. The samples were prepared by polymerizable complex method. Crystal structure of samples has been investigated by powder X-ray diffraction (XRD). Single-phase M-type strontium hexaferrites with chemical composition of Sr_1.05−xLa_xFe_12−xCo_xO₁₉ (x=0-0.4) were formed by heating at 1173 K for 24 h in air. Magnetic properties were discussed by measurements of M-H curves with vibrating sample magnetometer (VSM). La-Co substituted M-type strontium hexaferrites prepared by polymerizable complex method showed typical magnetic hysteresis of hard ferrite. The coercive force increased significantly by La-Co substitution with polymerizable complex method. Maximum coercive force achieved in this study is 8.0 kOe (640 kA/m). Scanning electron microscopy revealed that the prepared ferrite particles have plate-like shape of diameter range between 20 and 500 nm.     

Spectral and defect analysis of Cu-doped combustion synthesized new SrAl4O7 phosphor

A simple solution combustion synthesis route for preparation of Cu-doped SrAl₄O₇ has been described. Average particle size of 33 nm and platelet-like morphology has been observed. ESR studies confirm the presence of Cu in polycrystalline SrAl₄O₇. Bright-green luminescence under near-UV irradiation arising due to transition between Cu⁺ levels with microsecond level decay time makes it suitable for application in phosphor converted light emitting diode (LED). TL measurements show broad glow peaks which when deconvoluted indicate activation energies in the range of 0.6-1.1 eV and elucidate the trapping dynamics.     

Alkaline Earth–Olefin Complexes with Secondary Interactions

Strontium and calcium (alkaline earth: Ae) olefin complexes stabilised by secondary Ae???F?C and β‐agostic Ae???H?Si interactions are presented. Olefin coordination onto the alkaline earths is plain in the solid state, and it is thermodynamically favoured over the coordination of THF. The existence of the Ae???olefin interactions is corroborated by solution NMR data and DFT computations. The coordination mode of the olefin varies with steric effects and, if enforced, olefin dissociation can be compensated by the other non‐covalent interactions, as supported by DFT computations.