Thienylmanganese halides for the preparation of regioregular poly(3-hexylthiophene)

For the first time, thienylmanganese halides have been used for the synthesis of regioregular head-to-tail poly(3-hexylthiophene). A variety of conditions were examined, and the polymerization was successfully completed in the presence of Ni(dppe)Cl₂ at ambient temperature affording the title polymer in high yields with excellent regioregularity.     

Understanding Solid-Solid (fcc→ω+bcc) Transition at Atomic Scale

An atomic transition model of a face-centered cubic (fcc) crystal to a primitive hexagonal ω and body-centered cubic (bcc) structures has been crystallographically built. The fcc structure can transform into the ω structure through a local shuffling or displacement of atoms about 0.4014 Å in iron for a _{fcc iron} = 3.59 Å. The bcc structure can form either after the ω formation or concurrently by the similar mechanism, or the ω structure can be treated as an intermediate stage during the transition of fcc → bcc. Such a transition (fcc → ω + bcc transition) can be confirmed by Widmanstätten pattern formed in an iron meteorite, pearlitic structure and martensite composed of bcc-ferrite and ultra-fine ω particles in iron-carbon steels. The present fcc-bcc orientation relationship matches with Pitsch’s one.     

Magnetic fluctuation effects on Raman scattering in the organic superconductor κ-ET2Cu[N(CN)2]Br

We present a study of the 503, 880, 890, 901, 920, and 1475 cm⁻¹ Raman active κ-ET₂Cu[N(CN)₂]Br single crystal phonons, around T=40 K, where an anomaly in the longitudinal sound velocity and antiferromagnetic spin fluctuations have been detected. Doublets, narrowing of phonon lines and non-monotonic intensity variations, as a function of temperature, are observed indicating a possible interaction between phonon and correlated electrons.     

Synthesis and characterization of electrically conductive and fluorescent poly(N-[5-(8-hydroxyquinoline)methyl]aniline)/V2O5 xerogel hybrids

Poly(N-[5-(8-hydroxyquinoline)methyl]aniline)-intercalated vanadium pentoxide xerogel hybrids (PNQA/V₂O₅) were synthesized by in situ intercalative polymerization method. The results showed that the V₂O₅ maintains lamellar structure, but its interlayer spacing had increased from 1.18 to 1.76 nm. The electrical conductivity of the freshly prepared PNQA/V₂O₅ hybrid was 2 orders of magnitude higher than that of V₂O₅ xerogel. It was found that the aging in air facilitated the chain growth of PNQA between the V₂O₅ lamella, resulting in the increase in the electrical conductivity. The fluorescent analysis indicated that the emission band of the hybrid was red-shifted 19 nm in comparison with pure PNQA, and the quantum yield of the PNQA/V₂O₅ hybrids is 2–3 times higher than that of PNQA in ethanol.     

Electrically conductive and fluorescent poly[1,4-bis(3-alkyl-2- thienyl)phenylenes]: syntheses and preliminary characterization aspects

A series of polymers containing alternating phenylene and symmetrically substituted bithiophene repeat units have been synthesized and characterized using UV-Vis absorption spectroscopy, fluorescence emission spectroscopy, conductivity measurement and thermal analyses. The results reveal that the polymers have a bandgap energy of 2.5 eV and a fluorescence quantum yield of up to 26% with respect to quinine sulfate. The polymers show a maximum conductivity of 0.2 S cm⁻¹ upon doping with I₂ and display good thermal stability in both neutral and doped states. The influence of alkyl chain size on conductivity, spectral behavior and thermal stability is discussed.     

双[2-(对甲苯基)吡啶]乙酰丙酮合铱的合成及结构表征

以水合三氯化铱为原料,2-(对甲苯基)吡啶作环金属配体、乙酰丙酮作辅助配体合成了双[2-(对甲苯基)吡啶]乙酰丙酮合铱[(tpy)2Ir(acac)],通过质谱、氢谱、X射线单晶衍射分析表征手段确证了其分子结构。通过紫外可见光谱和光致发光光谱分析,研究了该配合物的光物理性能,在410和461 nm处有单重态和三重态吸收,在516 nm处有较强的绿光发射,表明该配合物是一种绿光材料。     

Preparation and spectroscopic, and thermal decomposition kinetic studies of europium(Ⅲ) complex [Eu(HNBD)3] (HNBD: 1-(6-hydroxy-1-naphthyl)-1,3-butanedione)

The complex of Eu(Ⅲ) with 1-(6-hydroxy-1-naphthyl)-1,3-butanedione (HNBD) was prepared for the first time and characterized by elemental analysis, IR, UV, fluorescence spectrum, and DTA-TG-DTG techniques. The IR and UV-visible spectra showed that Eu(Ⅲ) ion was coordinated to the HNBD ligand. The fluorescence spectrum showed the presence of Eu3+ characteristic emission. The TG-DTA-DTG curves showed that the thermal decomposition of the anhydrous complex was a two-stage process and the final residue was Eu2O3. The thermal decomposition kinetic parameters of the complex were evaluated from TG-DTG data by using three kinds of integral methods (Coat-Redfern equation, Horowitz and Metzger equation, Madhusudanan-Krishnan-Ninan equation). The kinetic parameters of the first stage are E* = 164.02 kJ·mol-1, A = 1.31 × 1015 s-1, △S*= 42.27 J·K-1·mol-1, △H*= 159.51 kJ·mol-1, △G*= 136.54 kJ·mol-1, and n = 3.1, those of the second stage are E*= 128.52 kJ·mol-1, A = 1.44 × 106 s-1, △S*= - 136.89 J·K-1·mol-1,△H*= 120.41 kJ·mol-1, △G*=283.85 kJ·mol-1, and n = 1.1.     

Identification of σ and Ω phases in AA2009/SiC composites

The microstructure evolution during ageing treatment at 170 and 190 °C of AA2009/SiC composites, reinforced with 15 vol.% particulates and whiskers, was studied by transmission electron microscopy. Besides θ′ and S′ phases, the typical hardening precipitates on Al–Cu–Mg alloys, it was found the presence of Ω and σ (Al₅Cu₆Mg₂) phases in the matrix. σ phase was only found in the matrix of particulate composite, while Ω phase appeared in both. This phase has not been previously observed in Al matrix composites based on conventional Al–Cu–Mg alloys.     

Fe_(73.5)Cu_1Nb_3Si_(13.5)B_9非晶合金的晶化动力学

用差热分析(DTA)结合X射线衍射(XRD),研究了Fe_(73.5)Cu_1Nb_3Si_(13.5)B_9非晶合金的晶化动力学。结果表明:温度在0～700℃范围内,该合金的晶化相为α-Fe和Fe_2B;α-Fe相晶化表观激活能为452.39kJ/mol,Fe_2B相的晶化表观激活能395.23kJ/mol;两相在晶化初期激活能最小,随晶化量X_c的增加而迅速增大,在α-Fe的体积分数为30％～80％,Fe_2B的体积分数为40％～80％时,呈现极大值。     

Preparation and characterization of graphene nanosheets/poly(3-hexylthiophene) thermoelectric composite materials

Graphene nanosheets/poly(3-hexylthiophene) (GNs/P3HT) composites were prepared by oxidative polymerization of 3-hexylthiophene in a GNs dispersed chloroform solution. The phase composition of the composite materials was analyzed by X-ray diffraction and Fourier transform infrared spectra. The thermoelectric properties of the cold pressed composite pellets with different GNs loadings were measured at room temperature. As the GNs loading increased from 0 to 30 wt.%, the electrical conductivity of the composites dramatically increased from ∼10⁻⁶ to ∼1.2 S/cm while the Seebeck coefficient slightly increased from 33.15 to 35.46 μV/K. The highest power factor (∼0.16 μW m⁻¹ K⁻²) was obtained in the 30 wt.% GNs/P3HT composite material.     

9-(4-乙氧羰基苯氧基)-6, 7-二甲氧基-1, 2, 3, 4-四氢吖啶盐酸盐对小鼠学习记忆功能的影响

目的: 研究 9-(4-乙氧羰基苯氧基)-6, 7-二甲氧基-1, 2, 3, 4-四氢吖啶盐酸盐(EDT) 对小鼠记忆功能的影响。方法: 采用小鼠跳台法和 Y-型迷宫法,观察 EDT 对小鼠学习记忆功能的影响。结果: EDT2.5、 5、10 mg·kg^-1灌胃 5 d, 对东莨菪碱、 亚硝酸钠和乙醇致小鼠记忆获得、巩固及再现障碍均有不同程度的改善作用。 结论: EDT 可以改善小鼠的记忆功能。     

离子交换法制备铂(II)和钯(II)的硝酸四氨络合物及结构表征

采用一种全新的方法—离子交换法,以二氯四氨合铂(II)和二氯四氨合钯(II)为原料,水为溶剂,制备铂、钯的重要催化前驱体化合物—硝酸四氨合铂(II)和硝酸四氨合钯(II)。通过元素分析、红外光谱、质谱、核磁共振表征其化学结构。方法的产率＞90%,产品纯度＞99.0%(以金属铂、钯计),适合于批量生产要求。     

预退火对Fe73.5Cu1Mo3Si13.5B9非晶合金的晶化及磁性的影响

本文研究了预退火温度和时间对Ｆｅ(７３．５)Ｃｕ１Ｍｏ３Ｓｉ(１３．５)Ｂ９非晶合金在最后退火过程中发生的 晶化及软磁性能的影响。结果表明：在较低温度下预退火能有效地控制合金的晶化过程,降低了最 后退火时所放出的晶化潜热。该合金在４５０℃进行１ｈ预退火发生部分晶化,释放约３２％的晶化 潜热,再经５１０℃保温１ｈ最后退火其磁性能与制备态样品经５１０℃退火后的磁性能相比,最大磁 导率ｍ显著提高,矫顽力Ｈｃ明显下降,Ｂｓ和Ｂｒ无明显变化。     

9-(4-乙氧羰基苯氧基)-6, 7-二甲氧基-1, 2, 3, 4-四氢吖啶盐酸盐对PC12细胞缺氧缺血损伤的保护作用

目的 研究9-(4-乙氧羰基苯氧基)-6, 7-二甲氧基-1, 2, 3, 4-四氢吖啶盐酸盐(EDT) 对神经细胞缺血缺氧损伤的影响。方法 离体培养的PC12 细胞, 用连二亚硫酸钠造成缺氧/复氧损伤模型, 用NaCN 加缺糖造成拟缺血损伤模型, 通过MT T 微量比色、培养介质LDH 活力测定研究EDT 对两模型的保护作用。结果 在10^-8～10^-6 mol·L^-1范围内, EDT 浓度依赖地降低两种损伤所致培养介质内LDH 的释放, 增加MTT 比色值, 同时10^-6 mol·L^-1 EDT 对两模型的保护作用具有时间依赖性, 48 h 达效应平台。结论 EDT 对PC12 细胞缺血缺氧损伤具有保护作用。     

Synthesis and optical properties of novel donor–acceptor poly(phenyleneethynylene)s containing quinoxaline

π-Conjugated polymers consisting of donor–acceptor repeating units often show a low band gap and hence have a good adsorbing efficiency of solar energy. Based on this fact, two novel π-conjugated polymers, PPE-1 and PPE-2, composed of electron-donating phenyl rings and electron-accepting quinoxaline units were prepared via Sonogashira polycondensation. The copolymers were characterised by NMR, FT-IR, GPC, TGA, UV and PL. These copolymers are thermostable and film forming. The PPE-1 and PPE-2 exhibited a decreased optical band gap (2.39 eV and 2.30 eV, respectively) compared to PPE homopolymer. And they showed red-shifted UV–vis absorption peak comparison with that of pure PPE. The absorption peak and PL emission peak of polymers are both red-shifted in solid state compared to polymers in solution due to strong inter-chain π–π interactions. Furthermore, the PL emission intensity of these copolymers is almost completely quenched when copolymers were blended with C60. The HOMO of two polymers estimated from CV is clearly lower in energy than MEH-PPV. This indicates that PPE-1 and PPE-2 are more oxidatively stable than MEH-PPV. The result shows that both PPE-1 and PPE-2 are useful for polymer solar cells.     

Synthesis, crystal structure and properties of the new semiconductor (EVT)4·[Pt(CN)4]

A novel radical cation salt based on of the donor (4,5-ethylenedithio-4′,5′-vinylenedithio)tetrathiafulvalene (EVT) with the square planar anion Pt(CN)₄²⁻ has been synthesized: (EVT)₄·[Pt(CN)₄] (1). According to the X-ray analysis its crystal structure includes EVT cation layers alternating with anion layers along the a-axis of the unit cell. The radical cation layer is formed by EVT stacks with β-packing type, the donors in stacks are tetramerized. The EPR spectra of a plate-like crystal of (EVT)₄·[Pt(CN)₄] salt shows a very weak signal with typical parameters of TTF derivative. The room temperature conductivity of salt 1 is 8×10⁻² Ω⁻¹ cm⁻¹ and the temperature dependence of the conductivity exhibits semiconducting character.     

Synthesis and photovoltaic properties of the copolymers of 2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylene vinylene and 2,5-thienylene-vinylene

The random copolymers of 2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylene vinylene (MEH-PV) and 2,5-thienylene-vinylene (ThV) were synthesized by Gilch method [H.G. Gilch, W.L. Wheelwright, J. Polym. Sci. Part A, Polym. Chem. 4 (1996) 1337; H. Becker, H. Spreitzer, K. Ibrom, W. Kreuder, Macromolecules 32 (1999) 4925; J.A. Mikroyannidis, Chem. Mater. 15 (2003) 1865], the alternate copolymer of MEH-PV and ThV was synthesized by Hornor–Emmons reaction, and poly(3-hexyl-thienylene-vineylene) was synthesized by Stille coupling reaction. The absorption characteristics of the copolymers were modulated by changing the ratio of ThV to MEH-PV units in the copolymers. With the increase of the ThV ratio, the absorption spectra of the copolymers were broadened and red-shifted in comparison with that of MEH-PPV. Hole mobility of the random copolymer with 18% ThV is an order higher than that of MEH-PPV. The polymer photovoltaic cells based on the blend of the copolymer and C₆₀ were fabricated and characterized by I–V and input photon to converted current efficiency (IPCE) measurements. Energy conversion efficiency under a white light (70 mW/cm²) of the photovoltaic cell based on the copolymer containing 18% ThV increased by 47% in comparison with that of the device based on MEH-PPV. The performance improvement of the polymer photovoltaic cell based on the random copolymers should benefit from the broader absorption and higher hole mobility of the copolymers.     

Roles of lithium ions and La/Li-site vacancies in sinterability and total ionic conduction properties of polycrystalline Li3xLa2/3−xTiO3 solid electrolytes (0.21 ≤ 3x ≤ 0.50)

The Li_0.33La_0.55TiO₃ solid electrolyte has a maximum grain ionic conductivity of 1.13 × 10⁻³ S cm⁻¹ among the Li_3xLa_2/3−xTiO₃ oxides (0.21 ≤ 3x ≤ 0.50), but the total ionic conductivity of its polycrystalline phase is not the highest. Owing to the grain-boundary resistances controlling the total resistances of bulk samples, an excellent solid electrolyte is mainly characterized by the grain-boundary resistances. With regard to the role of lithium ions, the substitution of La³⁺ ions by the Li⁺ ions weakens the strength of inter-ionic forces, leading to the decrease in the sintering temperature. The presence of La³⁺/Li⁺-site vacancies promotes the densification and grain growth and further results in rapid decreases in porosity and grain-boundary resistances. Li_0.21La_0.60TiO₃ with a larger amount of La³⁺/Li⁺-site vacancies can therefore exhibit the highest total ionic conductivity through rapidly decreasing its grain-boundary resistances by changing its microstructure, and it becomes a better polycrystalline solid electrolyte than Li_0.33La_0.55TiO₃ in the Li_3xLa_2/3−xTiO₃ system studied, in spite of its lower grain ionic conductivity.     

Synthesis and characteristics of poly(3-pyrrol-1-ylpropanoic acid) (PPyAA)-Fe3O4 nanocomposite

Poly(3-pyrrol-1-ylpropanoic acid) (PPyAA)-Fe₃O₄ nanocomposite was successfully synthesized by an in situ polymerization of 1-(2-carboxyethyl) pyrrole in the presence of synthesized Fe₃O₄ nanoparticles. Evaluation of structural, morphological, electrical and magnetic properties of the nanocomposite was performed by XRD, FT-IR, TEM, TGA, magnetization and conductivity measurements, respectively. XRD analysis reveals the inorganic phase as Fe₃O₄ and TGA shows about 90 wt% loading of Fe₃O₄ in the nanocomposite. FT-IR analysis indicates a successful conjugation of Fe₃O₄ particles with polypyrrole acetic acid. Magnetization measurements show that polypyrrole acetic acid coating decreases the saturation magnetization of Fe₃O₄ significantly. This reduction has been explained by the pinning of the surface spins by the possible adsorption of non-magnetic ions during the polymerization process. The conductivity and dielectric permittivity measurements strongly depend on the thermally activated polarization mechanism and thermal transition of PPyAA in the nanocomposite structure. Large value of dielectric permittivity (?′) of the nanocomposite at lower frequency is attributed to the predominance of species like Fe²⁺ ions and grain boundary defects (interfacial polarization).     

Electrodeposition and characterization of silane thin films from 3-(aminopropyl)triethoxysilane

3-(aminopropyl)triethoxysilane based films have been electrodeposited directly on polycrystalline gold and gold (111) electrodes in aqueous 3-(aminopropyl)triethoxysilane based electrolyte and in tetrahydrofurane based electrolyte. These films were characterized by means of IR-ATR and X-ray photoelectron spectroscopies. The film morphology was investigated by scanning tunneling microscopy while the film growth was observed by ellipsometry measurements. The vibrationnal and X-ray photoelectron analysis suggest that the chemical composition of the electrodeposited films either in liquid tetrahydrofurane or in liquid 3-(aminopropyl)triethoxysilane is identical. The resulting coating thickness is different for the same biasing time in the two liquid media. The gold surface is coated irreversibly by an amino terminated film of great interest for sensor applications which was used as the functionalized part of a surface plasmon resonance biosensor to monitor α-lactalbumin graft.