高碲酸合铜（Ⅱ,Ⅲ）配合物的合成和性质

在Ｈ６ＴｅＯ６／ＫＯＨ水溶液中以臭氧为氧化剂，将二价铜化合物氧化成三价铜化合物，并获得一个新的三价铜化合物Ｂａ４Ｋ［Ｃｕ（Ｈ２ＴｅＯ６）２］（ＯＨ）４．６Ｈ２Ｏ；描述了碱性溶液中“Ｃｕ（Ⅲ）／Ｃｕ（Ⅲ）”循环伏安图。对铜（Ⅲ）化合物，Ｎａ４Ｈ［Ｈ２ＴｅＯ６）２］．１７Ｈ２Ｏ以及相应的铜（Ⅱ）配合物的电子光谱和Ｃｕ２ｐＸＰＳ进行了研究，给出了其配位场场强参数和Ｃｕ２ＰＸＰＸ的电子结合能。由于价态升高     

乙醇-盐-水-5-Br-PADAP体系萃取分离测定钯

研究了在硫酸铵存在下 ,5 Br PADAP乙醇体系中Pd(Ⅱ )、Rh(Ⅲ )、Pt(Ⅳ )的萃取行为及乙醇溶液的分相条件 ,讨论了影响萃取率的各种因素 ,试验表明 ,室温下 ,一定 pH范围内 ,该体系中的Pd(Ⅱ )几乎可完全被乙醇相萃取 ,而Rh(Ⅲ )、Pt(Ⅳ )不被萃取或萃取率很低 ,从而可实现Pd(Ⅱ )、Rh(Ⅲ )、Pt(Ⅳ )混合离子的定量分离 ,同时建立了Pd(Ⅱ )的测定方法。乙醇相中Pd(Ⅱ ) 5 Br PADAP配合物表观摩尔吸光系数为 1.18× 10 5L·mol- 1·cm- 1,钯量在 0～ 9.6 0 μg/10ml范围内符合比耳定律 ,检出限为 0 .0 90 μg/10ml。用该法分离混合样和测定两种活性碳钯催化剂中钯 ,结果满意     

Ultraviolet photolysis of CH2I2 in methanol: O-H insertion and HI elimination reactions to form a dimethoxymethane product

Ultraviolet photolysis of low concentrations of CH2I2 in methanol solution found that CH2I2 is converted into dimethoxymethane and some H+ and I- products. Picosecond time-resolved resonance Raman (ps-TR3) experiments observed that the isodiiodomethane (CH2I-I) photoproduct decayed faster as the concentration of methanol increases, suggesting that isodiiodomethane is reacting with methanol. Ab initio calculations indicate isodiiodomethane is able to react with methanol via an O-H insertion/HI elimination to form an iodoether (ICH2-O-CH3) and HI products. The iodoether can then further react via another O-H insertion/HI elimination reaction to form the dimethoxymethane (CH3-O-CH2-O-CH3) observed in the photochemistry experiments. A reaction mechanism consistent with these experimental and theoretical observations is proposed.     

Comparison of the dehalogenation of dihalomethanes (CH2XI, where X = Cl, Br, I) following ultraviolet photolysis in aqueous and NaCl saltwater environments

The ultraviolet photolysis of low concentrations of CH(2)XI (X = Cl, Br, I) were investigated in water and saltwater solutions by photochemistry and picosecond time-resolved resonance Raman spectroscopy. Photolysis in both kinds of solutions formed mostly CH(2)(OH)(2) and HI and HX products. However, photolysis of the CH(2)XI molecules in saltwater resulted in production of some CH(2)XCl products not observed in aqueous solutions without salt present. The appearance of these new products in saltwater solutions is accompanied by a decrease in the amount of CH(2)(OH)(2), HI, and HX products compared to photolysis in aqueous solutions without salt present. The possible implications for photolysis of CH(2)XI and other polyhalomethanes in seawater and other salt aqueous environments compared to nonsaltwater solvated environments is briefly discussed.     

碳酸氢铵沉淀法制备氧化钇粉体时反应条件对产物粒度的影响

研究了碳酸氢铵沉淀法的反应条件对氧化钇粒度的影响,探讨了粒度变化规律。发现在沉淀反应中,晶型碳酸钇铵的形成与否是影响氧化钇粒度的关键因素。在较低的反应温度下,当碳酸氢铵和氯化钇的浓度大于0.25mol·L-1,摩尔比大于5,陈化时间大于60min时得到碳酸钇铵沉淀,经煅烧可获得粒度(D50)大于1μm的氧化钇。当反应物浓度较低、摩尔比小,陈化时间较短时得到无定型碳酸钇沉淀,煅烧沉淀可获得粒度(D50)小于0.5μm的氧化钇。实验证明选择适当的沉淀反应条件,可制备D50在0.3～10μm范围内的不同粒度级别的氧化钇粉体。     

Influence of the reaction temperature and ph on the coordination modes of the 1,4-benzenedicarboxylate (BDC) ligand: a case study of the Ni(II)(BDC)/2,2'-bipyridine system

Three new Ni(BDC)/2,2'-bipy compounds, Ni2(BDC)(HBDC)2(2,2'-bipy)2 (2), Ni3(BDC)3(2,2'-bipy)2 (3), and Ni(BDC)(2,2-bipy)2.2H2O (5), in addition to the previously reported Ni(BDC)(2,2'-bipy).0.75H2BDC (1) and Ni(BDC)(2,2'-bipy)(H2O) (4) [BDC = 1,4-benzenedicarboxylate; 2,2'-bipy = 2,2'-bipyridine], have been synthesized by hydrothermal reactions. A systematic investigation of the effect of the reaction temperature and pH resulted in a series of compounds with different compositions and dimensionality. The diverse product slate illustrates the marked sensitivity of the structural chemistry of polycarboxylate aromatic ligands to synthesis conditions. Compound 1, which has a channel structure containing guest H2BDC molecules, is formed at the lowest pH. The guest H2BDC molecules are connected by hydrogen bonds and form extended chains. At a slightly higher pH, a dimeric molecular compound 2 is formed with a lower number of protonated carboxylate groups per nickel atom and per BDC ligand. Reactions at higher temperature and the same pH lead to the transformation of 1 and 2 into the two-dimensional, layered trinuclear compound 3. As the pH is increased, a one-dimensional polymer 4 is formed with a water molecule coordinated to Ni2+. Bis-monodentate and bischelating BDC ligands alternate along the chain to give a crankshaft rather than a regular zigzag arrangement. A further increase of the pH leads to the one-dimensional chain compound 5, which has two chelating 2,2'-bipy ligands. Crystal data: 2, triclinic, space group P, a = 7.4896(9) angstroms, b = 9.912(1) angstroms, c = 13.508(2) angstroms, alpha = 86.390(2) degrees , beta = 75.825(2) degrees, gamma = 79.612(2) degrees, Z = 2; 3, orthorhombic, space group Pbca, a = 9.626(2) angstroms, b = 17.980(3) angstroms, c = 25.131(5) angstroms, Z = 4; 5, orthorhombic, space group Pbcn, a = 14.266(2) angstroms, b = 10.692(2) angstroms, c = 17.171(2) angstroms, Z = 8.     

High-efficiency, environment-friendly electroluminescent polymers with stable high work function metal as a cathode: green- and yellow-emitting conjugated polyfluorene polyelectrolytes and their neutral precursors

A series of aminoalkyl-substituted polyfluorene copolymers with benzothiadiazole (BTDZ) of different content were synthesized by Suzuki coupling reaction, and their quaternized ammonium polyelectrolyte derivatives were obtained through a postpolymerization treatment on the terminal amino groups. Copolymers are soluble in environmentally friendlier solvents, such as alcohols. It was found that the efficient energy transfer occurs by exciton trapping on the narrow band gap BTDZ site under UV illumination. Only 1% of BTDZ content is needed to completely quench a fluorene emission for both the neutral and the quaternized copolymers in the neat film. Absolute PL efficiencies of copolymer films were greatly enhanced as a result of the suppression of excimer formation. Light-emitting devices fabricated from these copolymers show high external quantum efficiencies over 3% and 1% for the neutral precursor and the quaternized copolymers, respectively, with high work function metals such as Al as a cathode. To the best of our knowledge, this is the first report on an electroluminescent polymer which bears the high EL efficiency, the electron-injection ability from high work function metals, and the solubility in environment-friendly solvents at the same time. These features make them a promising candidate for the next generation of light-emitting copolymers in PLED flat panel display application.     

Facile synthesis of exfoliated and highly conductive poly(arylene disulfide)/graphite nanocomposites

Exfoliated graphite has been synthesized by first synthesizing H₂SO₄ intercalated compound in a H₂O₂‐H₂SO₄ mixture, followed by exfoliation under microwave irradiation. Poly(arylene disulfide)/graphite nanocomposites were then fabricated by absorbing cyclic(arylene disulfide) oligomers into the pores of exfoliated graphite. Subsequently, the nanocomposite precursor was subjected to heat treatment to carry out the in situ ring‐opening polymerization of the oligomers via free radical mechanism. The as‐prepared nanocomposite exhibited a exfoliated nanostructure as evidenced by transmission electron microscopy (TEM) observation. The nanocomposite with a very small amount of graphite, 5 wt%, possesses a highly electrical conductivity of 4 S/cm, therefore, many applications can be found as conductive materials. Copyright © 2004 John Wiley & Sons, Ltd.