养殖池塘沉积物的重金属分布及污染特征

浙江省淅西北地区淡水养殖池塘沉积物重金属调查研究表明，养殖池塘沉积物中7种重金属元素分布不均衡，差异也较大，除Hg和Cr元素外，其余重金属元素已大大超过土壤本底值．虽然其实测含量都未超出国家规定的标准值范围，但沉积物中重金属元素对养殖水环境、养殖品种存在的潜在污染与危害值得关注．污染指数评价显示，养殖池塘沉积物中主要污染物质为Cu和Cr，而Hg、Pb污染程度相对较轻．     

Transition‐metal‐catalyzed reactions of 5‐methylene‐2‐oxazolidinone and 5‐methylene‐1,3‐thiazolidine‐2‐thione with isocyanates

5‐Methylene‐2‐oxazolidinone (1) and 5‐methylene‐1,3‐thiazolidine‐2‐thione (4) react with various isocyanates to give the corresponding urethanes 3 and 5 in high yields in the presence of palladium(0) or palladium(II) catalyst under mild reaction conditions. A mechanism is proposed. Copyright © 2003 John Wiley & Sons, Ltd.     

Synthesis and characterization of white‐light‐emitting polyfluorenes containing orange phosphorescent moieties in the side chain

Two orange phosphorescent iridium complex monomers, 9‐hexyl‐9‐(iridium (III)bis(2‐(4′‐fluorophenyl)‐4‐phenylquinoline‐N,C^2′)(tetradecanedionate‐11,13))‐2,7‐dibromofluorene (Br‐PIr) and 9‐hexyl‐9‐(iridium(III)bis(2‐(4′‐fluorophenyl)‐4‐methylquinoline‐N,C^2′)(tetradecanedionate‐11,13))‐2,7‐dibromofluorene (Br‐MIr), were successfully synthesized. The Suzuki polycondensation of 2,7‐bis(trimethylene boronate)‐9,9‐dioctylfluorene with 2,7‐dibromo‐9,9‐dioctylfluorene and Br‐PIr or Br‐MIr afforded two series of copolymers, PIrPFs and MIrPFs, in good yields, in which the concentrations of the phosphorescent moieties were kept small (0.5–3 mol % feed ratio) to realize incomplete energy transfer. The photoluminescence (PL) of the copolymers showed blue‐ and orange‐emission peaks. A white‐light‐emitting diode with a configuration of indium tin oxide/poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate)/PIr05PF (0.5 mol % feed ratio of Br‐PIr)/Ca/Al exhibited a luminous efficiency of 4.49 cd/A and a power efficiency of 2.35 lm/W at 6.0 V with Commission Internationale de L'Eclairage (CIE) coordinates of (0.46, 0.33). The CIE coordinates were improved to (0.34, 0.33) when copolymer MIr10PF (1.0 mol % feed ratio of Br‐MIr) was employed as the white‐emissive layer. The strong orange emission in the electroluminescence spectra in comparison with PL for these kinds of polymers was attributed to the additional contribution of charge trapping in the phosphorescent dopants. © 2007 Wiley Periodicals, Inc. JPolym Sci Part A: Polym Chem 45: 1746–1757, 2007     

Organometallic chemistry related to applications for microelectronics in Japan

This is meant to be a brief overview of the developments of research activities in Japan on organometallic compounds related to their use in electronic and optoelectronic devices. The importance of organometallic compounds in the deposition of metal and semiconductor films for the fabrication of many electronic and opto-electronic devices cannot be exaggerated. Their scope has now extended to thin-film electronic ceramics and high-temperature oxide superconductors. A variety of organometallic compounds have been used as source materials in many types of processing procedures, such as metal–organic chemical vapor deposition (MOCVD), metalorganic vapor-phase epitaxy (MOVPE), metal–organic molecular-beam epitaxy (MOMBE), etc. Deposited materials include silicon, Group III–V and II–VI compound semiconductors, metals, superconducting oxides and other inorganic materials. Organometallic compounds are utilized as such in many electronic and optoelectronic devices; examples are conducting and semiconducting materials, photovoltaic, photochromic, electrochromic and nonlinear optical materials. This review consists of two parts: (I) research related to the fabrication of semiconductor, metal and inorganic materials; and (II) research related to the direct use of organometallic materials and basic fundamental research.     

Catalysis by Ir(III), Rh(III) and Pd(II) metal ions in the oxidation of organic compounds with H2O2

Catalytic activities of three transition metals, as iridium (III) chloride, rhodium (III) chloride and palladium (II) chloride, were compared in the oxidation of six aromatic aldehydes (benzaldehyde, p‐chloro benzaldehyde, p‐nitro benzaldehyde, m‐nitro benzaldehyde, p‐methoxy benzaldehyde and cinnamaldehyde), two hydrocarbons (viz. (anthracene and phenanthrene)) and one aromatic and one cyclic alcohol (cyclohexanol and benzyl alcohol) by 50% H₂O₂. The presence of traces (substrate: catalyst ratio equal to 1:62500 to 1:1961) of the chlorides of iridium(III), rhodium(III) and palladium(II) catalyze these oxidations, resulting in good to excellent yields. It was observed that in most of the cases palladium(II) chloride is the most efficient catalyst. Conditions for the highest and most economical yields were obtained. Deviation from the optimum conditions decreases the yields. Oxidation in aromatic aldehydes is selective at the aldehydeic group only and other groups remain unaffected. This new, simple and economical method, which is environmentally safe, also requires less time. Reactive species of catalysts, existing in the reaction mixture are also discussed. Copyright © 2007 John Wiley & Sons, Ltd.     

Photo-Absorption and photochemical decomposition of copper and alkaline-earth ß-diketonates as source gases of high-Tc superconducting films

For low-temperature deposition of oxide films relating to Bi-Sr-Ca-Cu-O superconductors, photo-absorption and -decomposition properties were examined with respect to copper and alkaline-earth ß-diketonates. It was confirmed that all ß-diketonates examined were promising as source materials for photochemical vapour deposition (photo-CVD) using a low-pressure mercury lamp, in view of their large light absorption coefficients at wavelength 254 nm. The light irradiation was effective for the formation of highly crystalline oxide films at temperatures below 600 °C. By combining two sources, Ca₂CuO₃ and SrCuO₂ films were prepared. Photo-CVD of c-axis oriented Bi₂Sr₂CuO_x film was achieved by the irradiation of ternary sources of Bi(C₆H₅)₃ and strontium and copper ß-diketonates at 500 °C.     

Metal–Nitrosyl complexes as a source of new vasodilators: Strategies derived from systematic chemistry and nitrosyl ligand reactivity

A series of nitrosyl complexes of empirical formula K_n[M(CN)₅NO], where M = V, Cr, Mn and Co and n = 3, or M = Mo and n = 4, have been prepared which are notional analogues of the widely used vasodilator sodium nitroprusside. Their reactivity towards common nucleophiles (OH^?, NH₂R, NHR₂, HS^? and RS^?), acid and photolysis has been investigated to elucidate the desired properties required of new metal nitrosyls which may have some potential as new non-cyanide-based vasodilators.     

Initiation process of L‐lactide polymerization carried out with zirconium(IV) acetylacetonate

Lactide polymerization using zirconium(IV) acetylacetonate [Zr(acac)₄] as an initiator was investigated. In the reaction between Zr(acac)₄ and the monomer molecule, lactide deprotonation and the release of acetylacetone occurred. The structures of the obtained complexes were analyzed with high‐resolution NMR spectroscopy. A computational method was used to calculate the hypothetical structures. The role of the obtained complexes in the initiation of polymerization and the reaction of chain growth was proposed. The influence of the reaction temperature on the structures of the complexes was investigated. Polylactide chain growth proceeded by an insertion‐coordination mechanism. The polymer chain grew on one ligand, which was formed in advance from a deprotonated lactide. The molecular masses of the obtained polymers were the same as the theoretical masses and were directly proportional to the reaction conversion. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1886–1900, 2004     

Chelate polymers: II. Some novel transition metals complexes with azomethine‐containing siloxanes and their polyesters

New Schiff bases of 2,4‐dihydroxybenzaldehyde with siloxane‐α,ω‐diamines having different numbers of siloxane units in the chain have been synthesized and characterized by spectroscopy, elemental and thermal analyses. These azomethines were found to form complexes readily with copper(II), nickel(II), cobalt(II), cadmium(II) and zinc(II). From IR and UV–Vis studies, the phenolic oxygen and imine nitrogen of the ligand were found to be the coordination sites. Thermogravimetric analysis (TGA) data indicate the chelates to be more stable than the corresponding ligands. The melting points increase with shortening of the siloxane segment from azomethine, as well as the result of complexation. The chelates obtained were covalently inserted in polymeric linear structures by polycondensation through the OH‐difunctionalized ligand with 1,3‐bis(carboxypropyl)tetramethyldisiloxane. Direct polycondensation, assisted either by acetic anhydride or N,N′‐dicyclohexylcarbodiimide as dehydrating agent and the complex 4‐(dimethylamino)pyridinium 4‐toluenesulfonate as catalyst, was used for the synthesis of these compound types. The structures of the polymers obtained were confirmed by IR, UV and ¹H NMR. Characterization was undertaken by TGA, solubility tests and viscosity measurements. Copyright © 2003 John Wiley & Sons, Ltd.     

Kinetics and mechanism of the reactions of hexaaqua rhodium (III) with sulphur (IV) in aqueous medium

An O-bonded sulphito complex, Rh(OH₂)₅(OSO₂H)²⁺, is reversibly formed in the stoppedflow time scale when Rh(OH₂) ₆ ³⁺ and SO₂/HSO ₃ ⁻ buffer (1 <pH< 3) are allowed to react. For Rh(OH₂)₅OH₂₊+ SO₂ □ Rh(OH₂)₅(OSO₂H)²⁺ (k₁/k_-1), k₁ = (2.2 ±0.2) × 10³ dm³ mol⁻¹ s⁻¹, k₋1 = 0.58 ±0.16 s⁻¹ (25°C,I = 0.5 mol dm⁻³). The protonated O-sulphito complex is a moderate acid (K _d = 3 × 10⁻⁴ mol dm⁻³, 25°C, I= 0.5 mol dm⁻³). This complex undergoes (O, O) chelation by the bound bisulphite withk= 1.4 × 10⁻³ s⁻¹ (31°C) to Rh(OH₂)₄(O₂SO)⁺ and the chelated sulphito complex takes up another HSO ₃ ⁻ in a fast equilibrium step to yield Rh(OH₂)₃(O₂SO)(OSO₂H) which further undergoes intramolecular ligand isomerisation to the S-bonded sulphito complex: Rh(OH₂)₃(O₂SO)(OSO₂)^- → Rh(OH₂)₃(O₂SO)(SO₃)⁻ (k _iso = 3 × 10⁻⁴ s⁻¹, 31°C). A dinuclear (μ-O, O) sulphite-bridged complex, Na₄[Rh₂(μ-OH)₂(OH)₂(μ-OS(O)O)(O₂SO)(SO₃) (OH₂)]5H₂O with (O, O) chelated and S-bonded sulphites has been isolated and characterized. This complex is sparingly soluble in water and most organic solvents and very stable to acid-catalysed decomposition