Synthesis, characterization and magnetic properties of near monodisperse Fe3O4 sub-microspheres

Near monodisperse Fe3O4 sub-microspheres with an average diameter of 170 nm have been synthesized by a solvothermal reduction method, using K3[Fe（CN）6] as the raw material in the absence of any surfactants at 200~C℃ for 24 h. The products were detected by XRD, FESEM, TEM, and XPS. The investigation of the reaction parameters indicates that ethylene glycol plays a key role both as reducing agent and solvent. In addition, the reaction time and temperature also have important influences on the final product. The hysteresis loop of the near monodisperse Fe3O4 sub-microspheres shows a ferromagnetic behavior with saturation magnetization of 60.8 emu/g and coercivity of 124.7Oe.     

Nd isotopic variations and its implications in the recent sediments from the northern South China Sea

The chondrite-normalized REE distribution patterns in recent sediments from the northern South China Sea and surrounding areas are similar, with the HREE values being almost equal to or slightly higher, and the La_N/Lu_N ratio being lower, than PAAS standards. However, samples from the Xijiang River, a major branch of the Pearl River system, show opposite trends, i.e., with slightly lower HREE values and higher La_N/Lu_N ratio than PAAS. The distribution of Nd isotopes in sediments from the northern South China Sea was controlled by the Pearl River and the inshore area of South China, respectively. The volume of ε_Nd(0) from inshore areas of southern China is apparently higher than that from the Pearl River, and ε_Nd(0) values in offshore sediments and Taiwan Island are between these values. The results clearly show that ε_Nd(0) volume in the northeastern South China Sea is higher than in the southwest part of the northern South China Sea, indicating different source rock types. The main source rock of the Pearl River sediment is carbonate types and affects sediment deposition in the southwest of the northern South China Sea, while the source rock in the inshore area of southern China, mainly Mesozoic and Cenozoic granites, contributes to sediments in the northeastern area of the northern South China Sea. Due to different source rock types, the HREE values and the volume of ε_Nd(0) in recent sediments supplied by the inshore area of southern China are higher than those from the Pearl River. Over 80% of the rapidly accumulated sediments on the northern slope of the South China Sea in the southeast of Dongsha Islands area were derived from Taiwan Island and from inshore areas of South China, with only less than 20% from the Pearl River. Supported by National Natural Science Foundation of China (Grant Nos. 40276019, 40238060 and 40621063), and National Basic Research Program of China (Grant No. 2007CB819501)     

Preparation of nano-crystal N-Zn/TiO<Subscript>2</Subscript> anode films and the effects of co-sensitization on the performance of dye-sensitized solar cells

A nano-crystal N-Zn/TiO₂ anode film was prepared using a combined technology. X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy and cyclic voltammetry characterizations showed that the two elements N and Zn were doped into nano-crystal TiO₂ successfully. This resulted in a strong redshift in the UV-Visible spectrum. UV-Visible measurements showed that the light absorption of N719 and P3OT were complementary and covered the entire visible region. This led to a high utilization of visible light. Solar cells based on the N-Zn/TiO₂ anode film were co-sensitized using P3OT and N719. The cells have a short-circuit current density of 7.91 mA/cm², an open-circuit photovoltage of 0.659 V, and a photoelectric conversion efficiency of 2.64%. Also, the relationship among the N-Zn/TiO₂-film anode’s electric structure, the dye’s LUMO, electrochemical impedance, and photoelectric conversion efficiency are discussed in the paper.     

疏水性固体酸H3PW12O40/HZSM-5催化合成丙烯酸正丁酯

制备了负载型疏水性固体酸催化剂H₃PW₁₂O₄₀/HZSM-5，并将该疏水性固体酸催化剂用于丙烯酸（简称AA）与正丁醇的酯化反应中。结果表明，硅铝摩尔比为60的HZSM-5负载质量分数为40％的H₃PW₁₂O₄₀，180℃干燥2h，H₃PW₁₂O₄₀/HZS-5催化剂的活性最高，丙烯酸转化率可达96.44％。H₃PW₁₂O₄₀/HZSM-5催化剂循环使用4次，丙烯酸的转化率仍保持在71.98%。采用XRD、FTIR以及原位红外对催化剂的结构和酸性进行了表征，测试结果均表明H₃PW₁₂O₄₀较好的分散于HZSM的表面，在催化剂表面存在Lewis酸和Brnosted酸，且其负载型疏水性固体酸H₃PW₁₂O₄₀/HZSM-5的酸量、催化活性和疏水性能均高于单组分H₃PW₁₂O₄₀。     

The synthesis and properties study of 6,13-diphenylpentacene

6,13-diphenylpentacene（DPP） was synthesized by 6,13-pentacenequinone and the Grignard reagent with the SnCl2/HCl as the reducing agent. It was detected by ^1H NMR, infrared spectra, X-ray diffraction （XRD）, UV-visible spectra and fluorescence spectra. Substitution with phenyl at the C-6 and C-13 positions of pentacene leads to phenomenal enhancement in solubility and a little enhancement in photooxidative stability. XRD results showed that the pattern of 6,13-diphenylpentacene was different from the patterns of pentacene and 6,13-pentacenequinone. UV-Visible spectra showed that the λmax of DPP in HCCl3 was 600 nm. The fluorescence spectra showed that DPP emitted purple （430 nm） and red （612 nm） when excited by UV, while only emitted red when excited by visible light. But it is still susceptible to photooxidation. The photooxidation product of DPP was also studied.     

杯芳烃内相中3-环丁烯砜的分解反应研究

采用分子动态模拟及量子化学方法对杯芳烃内相中3环丁烯砜的取向及分解为二氧化硫和丁二烯的反应进行了研究。结果表明,3-环丁烯砜在杯芳烃分子反应器中发生分解反应的活化能比在自由状态下反应的活化能略高,这与3-环丁烯砜在杯芳烃中的表观分解温度提高的实验现象吻合。分析分子反应器与小分子的相互作用能以及分子反应器的变形能随反应进程的变化趋势,发现活化能的变化主要源自分子反应器与小分子的相互排斥作用。     

β二酮二亚胺Zn配合物桥联二聚体的理论研究

从理论上探讨和研究了LZn(μ-X)2ZnL(L={HC(CMeNPh)2})配位化合物的不同桥接基团衍生物的性质。采用B3LYP方法,选用6-31+G**基组对其进行了计算及分析。结果表明过渡金属与配体间存在广泛的电子给体-受体作用。在含有不同的桥接基团(X=F,OH,NH2,Cl,SH,PH2)的此类配位化合物间,当桥接基团分别为F,OH,NH2和Cl,SH,PH2时配位化合物四元桥环稳定性逐渐增强。同时从稳定性上讲,第2周期大于相应的第3周期桥联化合物。其中,带电荷数较低的PH2配位化合物有着较强的电子给体-受体作用,稳定化能较高。Wiberg键级也大于其他配位化合物,因而桥键比较稳定。     

新型酚氧基酞菁的合成及其光谱性质

采用醇锂法和插入法合成了三种α-（4-羟基苯氧基）₄酞菁(中心元素为2H,Zn或Mg),产物经IR,UV-vis,¹H-NMR和MS表征。重点考察了三种化合物的两亲性,聚集性和光物理性质。结果表明,此类酞菁具有良好的两亲性,α位引入的对羟基苯氧基降低了在溶剂中的聚集程度,分子内光致电子转移使得荧光量子产率降低,有可能成为一种优良的Ⅰ型光敏剂。