两种ω-二茂铁羧酸的改进合成及其电化学行为

利用 Zn(Hg) /HCl分别对 3-二茂铁甲酰基丙酸和 4-二茂铁甲酰基丁酸进行 Clemmensen还原 ,在温和条件下高收率 (93%以上 )合成了 4-二茂铁丁酸和 5 -二茂铁戊酸。新的合成方法避免了文献中采用 40 5 .3k Pa H2 还原的苛刻条件。以FT-IR、1HNMR、13CNMR和 L D-MS确证了产物的结构。利用循环伏安技术研究了这两种 ω-二茂铁羧酸的电化学行为。

含环己烯、二氮杂萘结构的新型聚醚酮的合成及表征

合成了一种新型单体 1 -甲基 -4 ,5 -二 (4-氯代苯甲酰基 )环己烯 ,该单体与 4-(4-羟基苯基 )-2 ,3 -二氮杂萘 -1 -酮单体经亲核取代反应 ,成功地合成了含环己烯结构的杂环联苯型聚醚酮聚合物。用FT -IR、1H -NMR、DSC、X -射线衍射等方法对该聚合物进行了表征 ,并研究了它的溶解性能。结果表明 ,这种可溶性无规共聚物 ,有较高的玻璃化温度 ,并且结构中有不饱和双键 ,是一种反应性高分子。

Synthesis and characterization of novel bipolar PPV-based copolymer containing triazole and carbazole units

Two new blue light-emitting PPV-based conjugated copolymers containing both an electron-withdrawing unit (triazole-TAZ) and electron-rich moieties (carbazole-CAR and bicarbazole-BCAR) were prepared by Wittig condensation polymerization between the triazole diphosphonium salt and the corresponding dialdehyde monomers. Their structures and properties were characterized by FT-IR, TGA, DSC, UV-Vis, PL spectroscopy and electrochemical measurements. The resulting copolymers are soluble in common organic solvents and thermally stable with a T-g of 147degreesC for TAZ-CAR-PPV and of 157degreesC for TAZ-BCAR-PPV. The maximum photoluminescence wavelengths of TAZ-CAR-PPV and TAZ-BCAR-PPV film appear at 460 nm and 480 nm, respectively. Cyclic voltammetry measurement demonstrates that TAZ-BCAR-PPV has good electrochemical reversibility, while TAZ-CAR-PPV exhibits the irreversible redox process. The triazole unit was found to be an effective pi-conjugation interrupter and can play the rigid spacer role in determining the emission colour of the resulting copolymer.

Spectrometric investigation on the thermooxidative degradation of ethylene oxide and tetra-hydrofuran co-polyether

The thermooxidative degradtion of ethylene oxide and tetra-hydrofuran (EO-THF) co-polyether has been studied by electron spin resonance (ESR), Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy. The initial degradation site was found to be at the a-carbon of the ether bond. Two free radicals which derived from dehydrogenation and oxygen addition were successfully detected by spin-trapping technique which used alpha -phenyl-N-tert-butyl nitrone(PBN) as spin trap. Both FT-IR and NMR have been used to follow structural changes of the copolyether during degradation. Nearly 20 product fragments including formate, carbonate, methyl, alcohol, methylene-dioxy, hydroperoxide and semiformal have been characterized by D-1 and D-2 NMR. The thermooxidtion of co-polyether preferred to occur on the THF units especially at the alternating linkage of EO and THF. Antioxidant (BHT) not only retarded the thermooxidation but also modified the degradation products with less ester and methylene-dioxy groups hut more hydroxyl and methyl groups.

Structural studies of excimer laser-induced percolative phase transition on polyimide thin film surfaces

The behavior of electrical conductivity for excimer laser irradiated polyimide films in the vicinity of the critical number of laser shots was described by three-dimensional percolative phase transition model. It is: found that electrical conductivity changed more rapidly than that predicted by the percolation model. Thus, the change in microstructure with increasing number of laser shots was analyzed by FT-IR Raman spectrometry and laser desorption time-of-flight mass spectrometry. It is demonstrated that not only the number but also the average size of graphite particles on the irradiated polyimide film surfaces increased with increasing number of laser shots. These results were helpful to better understand the critical change in electrical conductivity on the irradiated polyimide film surfaces. (C) 2001 Elsevier Science B.V. All rights reserved.

多种谱学方法研究环氧乙烷/四氢呋喃共聚醚的热氧降解

采用电子自旋共振 (ESR)、傅里叶变换红外光谱 (FT IR)和多种核磁共振 (NMR)技术研究了环氧乙烷 /四氢呋喃共聚醚的热氧降解 ,表征了近 2 0种产物结构碎片 ,并对EO和THF两种链节的降解作了定量讨论。共聚醚的氧化降解发生在醚键氧碳上 ,遵循自由基氧化机理 ,最后形成大量的甲酸酯、碳酸酯等酯类以及甲基、亚甲二氧基和醇 ,此外还检测到过氧化氢和半缩甲醛结构。分析表明共聚醚中THF链节的降解程度明显大于EO链节 ,而且降解容易发生在两种链节交替连接处。抗氧剂 2 ,6 二叔丁基 4 甲基酚 (BHT)不仅降低了共聚醚的氧化降解程度 ,还改变了降解产物的结构分布 ,显著抑制了碳酸酯和亚甲二氧基结构的生成 ,相对增加了羟基和端甲基结构

含环己烯氮杂环结构的聚醚砜酮三元共聚物合成

用 1 -甲基 -4 ,5-二 ( 4-氯代苯甲酰基 )环己烯与 4 -( 4-羟基苯基 ) -2 ,3 -二氮杂萘 -1 -酮、4 ,4′-二氯二苯砜经亲核共缩聚反应 ,合成了含环己烯结构的杂环联苯型聚醚砜酮三元共聚物。用FT -IR、1H -NMR、DSC、X -射线衍射等方法对聚合物进行了表征 ,并研究了聚合物的溶解性能。结果表明 ,聚合物是一种具有较高的玻璃化转变温度的可溶性无规共聚物。聚合物含有不饱和双键结构 ,是一种反应性高分子。

LLDPE/LLDPE-g-AA共混物的接触角及红外光谱表征

利用熔融共混的方法制备了线性低密度聚乙烯/线性低密度聚乙烯接枝丙烯酸(LLDPE/LLDPE-g-AA)共混物。用傅里叶红外光谱(FT-IR)和测定接触角的方法对不同LLDPE-g-AA含量的LLDPE/LLDPE-g-AA共混物膜的表面进行了表征。结果表明,随着共混物中LLDPE-g- AA含量的增加,水和甘油等极性液体与共混物表面的接触角下降。依据共混物的FT-IR计算了其羧基峰强度。发现极性液体与LLDPE/LLDPE-g- AA共混物膜表面的接触角越小,羧基峰强度越大。

Synthesis and properties of three tris(1,10-phenanthroline) ruthenium (II) derivatives

Three new asymmetrical ruthenium (II) complexes: [Ru(phen)(2){phen-NHCO(CH2)(4)Br}](PF6)(2), [Ru(phen)(2){phen-NHCO(CH2)(5)Br}](PF6)(2) and [Ru(phen)(2){phen-NHCO(CH2)(10)Br}](PF6)(2) were synthesized, which were confirmed by the technique of FT-IR, H-1 NMR and ESI-MS. The electrochemical and fluorescent properties of three Ru (II) complexes were investigated with cyclic voltammetry and fluorometry.

Synthesis, electrochemistry and fluorescence of four new Ru(phen)(3)(2+) derivatives

Four typical LB monolayer film materials, Ru(phen)(3)(2+) complexes with one ligand attached to different long chain alkyl amides, were designed and synthesized. Their chemical structures were identified by the techniques of FT-IR, H-1 NMR and ESI-MS. Also, UV-Vis, electrochemistry and fluorescence of these complexes are reported.

Sol-gel thin-film immobilized soybean peroxidase biosensor for the amperometric determination of hydrogen peroxide in acid medium

An acid-stable soybean-peroxidase biosensor was devel oped by immobilizing the enzyme in a sol-gel thin film. Methylene blue was used as a mediator because of its high electron-transfer efficiency. The sol-gel thin film and enzyme membrane were characterized by FT-IR, and the effects of pH, operating potential, and temperature were explored for optimum analytical performance by using the amperometric method. The H2O2 sensor exhibited a fast response (5 s), high sensitivity (27.5 mu A/mM), as well as good thermostability and long-term stability. In addition, the performance of the biosensor was investigated using flow-injection analysis (FIA).

Synthesis and characterization of a water-soluble endohedral metallofullerol

A water-soluble endohedral metallofullerol, Pr@C82Om(OH)(n)(m approximate to 10 and n approximate to 10), was successfully synthesized through the reaction of a pure endohedral metallofullerene, Pr@C-82, with a concentrated nitric acid and a subsequent hydrolysis process. The formation of endohedral metallofullerols Pr@C82Om(OH)(n) is thought to involve a NO2 radical formation step, in much the same way as the reaction of empty fullerenes. FT-IR, XPS, and LD-TOF MS techniques were employed to characterize the structure of the endohedral metallofullerol from the above reaction.

Fabrication and characterization of heteropolyanion Langmuir-Blodgett films

The possibility of the formation of Langmuir-Blodgett (LB) films with dimethyldioctadecylammonium (DODA) after the addition of cobalt(II)-substituted Dawson-type tungstodiphosphate anion (briefed as (H2O)(CoP2W17O618-)-P-11) in the subphase has been explored. Marked modifications of the compression isotherms are observed when this anion is dissolved in the subphase, which demonstrates that the polyanions interact with the monolayers. LB films have been readily obtained from this system. The adsorption Fourier transform IR (FT IR) spectroscopy, atomic force microscopy (AFM), X-ray diffraction (XRD) and cyclic voltammetry (CV) have been used to investigate the morphological and molecular structure of the deposited film. The FT IR results showed the presence of the polyanion within the LB films, and the shift for its characteristic bands may be related to the presence of positively charged DODA. AFM measurement reveals that the LB films of DODA/(H2O)(CoP2W17O618)-P-II are regularly and uniformly deposited on the substrate. XRD experiments prove that the lamellar structure of the LB films of DODA/(H2O)(CoP2W17O618-)-P-II is well-defined. The LB films of DODA/(H2O)(CoP2W17O618-)-P-II immobilized onto an indium-oxide (ITO) glass, in aqueous solutions of pH 2.0-5.0, show quite facile redox reactions even for multilayers. All the experiments carried out in the present study suggest that the new materials of heteropolyanions can be formed by LB techniques and beneficial physicochemical properties of heteropolyanions can be maintained/enhanced through molecular-level design. (C) 1999 Elsevier Science S.A. All rights reserved.

TiO_2纳米粉的热处理过程研究

用溶胶凝胶法制备出纳米凝胶粉，于不同温度下热处理形成纳米晶，研究热处理温度对粒子大小、形貌、品相转变及吸附能力的关系．XRD、FT-IR、Raman光谱研究表明200～600℃热处理1h的TiO2纳米晶为锐钛矿相，在700℃热处理的纳米晶为锐钛矿相与金红石相共存，800℃热处理的纳米晶完全为金红石相;TEM、TG、XPS的结果证明热处理温度越高，纳米粒子的粒径越大，吸附能力也越弱.

推进剂组分对聚醚聚氨酯粘合剂热氧降解的影响 (Ⅱ)固体填料和助剂的影响

采用FT-IR和多种NMR技术研究了推进剂中常用的几种填料和助剂对聚醚聚氨酯粘合剂热氧降解的影响。高氯酸铵、奥克托金、铝粉、硝化纤维素、键合剂、碳黑等均不改变聚氨酯粘合剂的降解机理，但表现出不同程序的稳定作用。过氯酸铵的吸附作用使样品始终保持固体形态，而含其它组分的样品在降解过程中逐渐变为液态。在ＮＥＰＥ推进剂的热氧降解过程中，硝酸酯和中定剂逐渐挥发分解，粘合剂发生降解，导致推进剂强度降低。