New 4,7-dithienebenzothiadiazole derivatives with cyano-vinylene bonds: Synthesis,photophysics and photovoltaics

Two conjugated compounds P and T which contained 4,7-dithienbenzothiadiazole as central unit and terminal phenyl or thiophene rings, respectively, connected via a cyano vinylene bond, were synthesized. The stable intramolecular charge-transfer status makes possible the compounds to increase the optical absorption band. These compounds exhibited excellent film-forming properties which allowed the preparation of homogenous thin films by the spin-coating technique. The compounds were stable up to about 300 °C and showed glass transition temperatures of 64 and 50 °C. The absorption spectra were broad and extended from about 300 to 700 nm. They emitted yellow-orange light in solution with photoluminescence (PL) maximum at 574, 578 nm and reddish light in solid state with PL maximum at 663, 702 nm. Organic solar cells based on T (or P) as donor and C60 derivative as acceptor exhibit power conversion efficiencies (PCEs) of 0.11% (or 0.09%) under one sun of AM1.5 illumination.     

Effects of Microfiltration and Storage Time on Cholesterol,Cis-9, Trans-11 and Trans-10, Cis-12 Conjugated Linoleic Acid Levels,and Fatty Acid Compositions in Pasteurized Milk

The effects of microfiltration and storage time on the contents of cholesterols, conjugated linoleic acids, particle size distributions, and fatty acid profiles in pasteurized milk were investigated over 7 days. After microfiltration, the cholesterol (except for day 7) and trans-10, cis-12 conjugated linoleic acids did not change in microfiltered and pasteurized milk and in pasteurized milk. Compared with pasteurized milk, the cis-9, trans-11 conjugated linoleic acids, and ω-6/ω-3 ratio decreased by 43 and 12%, while d₃₂, d₄₃, C18:3n-3, and C20:5n-3 increased by 52–57, 70, 3.2–5.8, and 4.8–2.6% in microfiltered and pasteurized milk, respectively. The contents of cis-9, trans-11 conjugated linoleic acids, and cholesterols were higher on day 7 than on day 0, while the ω-6/ω-3 ratio and C22:6n-3 showed the opposite tendencies. Storage time did not affect d₃₂ (except for microfiltered and pasteurized milk) and d₄₃. These highlighted that microfiltration has the potential to retain ω-3 fatty acids, decreased the ω-6/ω-3 ratio and maintain the stability of microfiltered and pasteurized milk shelf life.     

聚电解质-表面活性剂固态复合物

聚电解质与相反电荷的表面活性剂在溶液中通过分子自组装生成聚电解质－表面活性剂固态复合物（ＰＥ－Ｓｕｒｆｓ）。ＰＥ－Ｓｕｒｆｓ具有较好的热学、力学及光学性能。已在可控渗透膜、光电响应性有机薄膜及化学传感器等领域显示出很好的应用和发展前景,通过改变聚电解质与表面活性剂的结构和种类可制备具有不同结构和性能的功能材料,文中对ＰＥ－Ｓｕｒｆｓ的制备、结构与性能以及应用前景进行了概述。     

Conjugated linoleic acid and oxidative stress

At the present time, conjugated linoleic acid (CLA) is the subject of a growing number of studies since it has been demonstrated to possess anticarcinogenic and antiatherogenic activities in experimental animal models and to increase in some pathological states in humans. In both situations, CLA has been claimed to be involved in oxidative stress, as an antioxidant in the first case and as a primary product of a free-radical attack on polyunsaturated fatty acids (PUFA) in the other. The controversial results are due mostly to a lack of a suitable methodology because the presence of conjugated dienes (CD) in lipid moiety has been taken for years as evidence of lipid peroxidation due to the occurrence of this structure in fatty acid hydroperoxides. We have recently developed a new methodology that consists of the extraction of fatty acids, including CD fatty acid hydroperoxides, by mild saponification and their separation and identification by high-performance liquid chromatography with diode array detector. Fatty acid analyses of liver homogenate, oxidized in vitro either with Fe-ADP or t-butyl hydroperoxide (t-ButylHP), of lamb and rats fed CLA at levels known to prevent carcinogenesis, showed that CLA and its metabolites steadily decreased during oxidative stress and that they are more prone to oxidation than their corresponding methylene-interrupted fatty acids. No significant antioxidant effect of CLA was detected in any model tested. However, CD fatty acid hydroperoxides increased in the t-ButylHP model but not in the Fe-ADP model, owing probably to the degradation of CD fatty acid hydroperoxides induced by this oxidative agent. In conclusion, CLA and its metabolites seem to behave, under oxidative stress, as regular PUFA. Thus, it is highly unlikely that the peculiar effects of CLA are directly related to interference in lipoperoxidative processes.     

水解聚丙烯酰胺盐水溶液表观粘度的数学模拟(Ⅳ)──存在二价金属离子时的通用MHS方程式

对于水解聚丙烯酰胺的一价金属离子和二价金属离子的混合盐水体系,提出二价阳离子对一价阳离子降低特性粘数的等效系数概念．发现这一系数仅与二价阳离子的离子强度分数有关,并可用三次多项式描述．经该系数修正的通用MHS方程式不仅仍保留了本文（Ⅰ）报原方程式的形式,而且由此修正式预测的特性粘数值与实验值吻合良好.此外还观察到阴离子Cl~-、SO_4~(2-)和HCO_3~-对特性粘数没有影响,而CO_3~(2-)却使其略有增大．     

Anodic and Cathodic Electrochemically Generated Chemiluminescence in Conjugated Polymers

In the present contribution, we show that long‐lived electrochemically generated chemiluminescence (ECL) from conjugated polymers can be achieved in both anodic and cathodic polarizations of poly[2‐(2′‐ethylethoxy)‐5‐methoxy‐1,4‐phenylene vinylene] (MEH–PPV), when the appropriate electrochemical conditions are adopted and an adequate degree of purity for the active polymer, solvent, and supporting electrolyte is achieved. The quantum efficiency is generally higher during the anodic polarization of MEH–PPV, whereas the ECL vs. time profile depends on the nature of the supporting electrolyte. Such findings led to the conclusion that the kinetics of the doping/undoping processes in MEH–PPV represents a crucial factor in determining the emissive properties of the conjugated polymer. A comparison of the ECL emission from analogous polymeric systems, namely poly[2,5‐bis‐(triethoxymethoxy)‐1,4‐phenylene vinylene] (BTEM–PPV) and poly[2,3‐dibutoxy‐1,4‐phenylene vinylene] (DB–PPV), is also reported.     

Self‐Assembled Monolayer Transistors

Self‐assembled monolayers of organic, conjugated molecules can be used as active components of field‐effect transistors. The length of the molecule can define critical device dimensions with high precision on the nanometer scale. Transistor effects on the molecular‐scale as well as in devices consisting of single active molecules have been demonstrated. The observed device performance indicates that such transistors might be useful for switching and amplifying electrical signals in logic circuits. Moreover, functionalizing the organic molecules reveals that different parts of the molecule can act as gate insulator or the active component of transistors. Such research might pave the way to molecular electronic applications.     

Squeezing Organic Conjugated Molecules—What Does One Learn?

The effects of hydrostatic pressure on conjugated polymers, in particular polyphenyls (see Figure for monomer unit) have been studied using photoluminescence, absorption, photo‐induced absorption, and Raman spectroscopy. The effect of pressure on the singlet and triplet excitons and polarons allows an understanding of localized and delocalized electronic states. Changes in the intensity ratios of Raman bands that correspond to vibrations of a perpendicular and a coplanar array of phenyl rings in the chain, and comparison with calculated intensities, demonstrate the influence of pressure on the polymer's conformation.