硅胶固载光敏剂的合成及其在反式维生素D3光敏异构化为顺式维生素D3中的应用

采用丙二酸作为连接,针9－蒽甲醇连接到硅胶上生成硅胶固载的光敏剂。利用此因相光敏剂分别在乙醇和甲苯溶液中敏化反式维生素D3。实验结果表明，此固相光敏剂能够有效地敏化反式维生素D3为顺式维生素D3的反应，并且非常容易从反应体系中分离出来。     

Photoresponsive peptide and polypeptide systems: part II. Photochromism of poly(l-ornithine) containing various azo-contents in side chains

Poly(L-ornithine)s having various azo-contents in the side chains were synthesized by the water-soluble carbodiimide procedure. The photochemical properties of the polypeptides poly[N^δ-p-(phenylazo)benzoyl-L-ornithine] (PPABLO) containing 3–77 mol% azobenzene were investigated by absorption and circular dichroism spectroscopy in hexafluoro-2-propanol (HFIP) or water, and in HFIP-water or methanol-water solvent mixtures. The photochromism of the dichroic bands of the PPABLOs containing 20–77 mol% azobenzene in the visible and ultraviolet wavelength regions was found to be mostly reversible as a function of irradiation time at different wavelengths due to the photostationary state (above 80% trans-cis photoisomerization) of the azo aromatic moieties. The PPABLO containing 3.2 mol% azobenzene in water exhibited conformational changes from random coil to helix by the addition of methanol or sodium dodecyl sulphate (SDS). The photo-induced conformational change was observed in HFIP-water-SDS solvent mixtures, while no conformational change was seen in water and HFIP-water solvent mixtures.     

光响应型分子的合成及应用研究进展

光响应型分子作为一种刺激性响应分子,因其具有信号稳定、远程控制、瞬时性和环保性等优势,而广泛应用于智能材料、光控器件等领域,其中最典型、研究最广泛的当属光致异构分子。光致异构分子在特定波长光照下会发生结构变化,在宏观上有时会表现出颜色的改变,在另一波长光照下结构会重新变为原来的结构,颜色也会随之褪去。综述了螺吡喃、偶氮苯、二芳基乙烯等几种主流的光致异构分子的合成与制备、光响应机理以及在盐湖资源提取、药物检测、储能材料制备等实际生产生活中的应用,并对光响应分子在低成本环境友好合成、复合功能材料化、智能分子器件等方面的发展趋势进行了展望。     

Synthesis and characterization of a new family of photoactive liquid crystalline polyesters based on α‐methylstilbene

A liquid crystal polyester and two liquid crystal copolyesters containing α‐methylstilbene moieties and aliphatic or aromatic spacers in the backbone were synthesized in good yields, with the aim of using them for photosensitive microcapsule preparation. The synthesized polymers were fully characterized with respect to thermal stability, type of mesophase, molecular weight and E–Z photoisomerization. Combination of monomers with different structures allowed adjustment of the polymer characteristics such as degree of crystallinity and glass transition temperature, as verified using X‐ray diffraction, polarized optical microscopy and differential scanning calorimetry. Quantitative ¹H NMR and UV‐visible experiments were performed in order to investigate E–Z photoisomerization after photoirradiation at 364 nm. Finally, a membrane based on one of these polymers was prepared and it was found that its wettability increased on photoirradiation. © 2013 Society of Chemical Industry     

以含偶氮苯基团为侧链对芳香聚酰胺的改性

以对苯二甲酰氯分别与4,4’-二氨基二苯醚和4,4’-二氨基二苯甲烷2种芳二胺反应得到聚酰胺PA1和PA2,然后以含偶氮苯基团的NAzO4Br对PA1和PA2进行结构及性能改性研究,分别得到了5种不同配比改性的NAzO4-PA1和NAzO4-PA2;并通过红外光谱、核磁共振氢谱、紫外可见光谱和X射线衍射等方法对改性聚酰胺进行了结构表征。结果表明,改性得到的聚酰胺NAzO4-PA1和NAzO4-PA2具有较好的光致异构性和热稳定性,而且含偶氮苯基团侧链的引入,使聚酰胺在二甲基乙酰胺(DMAc)、二甲基亚砜(DMSO)和二甲基甲酰胺(DMF)中具有良好的溶解性。     

偶氮苯光致异构储能材料的研究进展

利用可逆的光异构化捕获、转换、储存和以热的形式释放太阳能的偶氮苯光致异构储能材料成为目前研究的主要焦点之一.近年来,偶氮苯在光储能方面取得了一定的研究成果.介绍偶氮苯光致异构储能材料的储能机理及主要性能指标的基础上,重点介绍了偶氮苯光致异构储能材料半衰期、能量密度和可见光储能的研究现状,分析了各偶氮苯用于储能的优劣势,展望了偶氮苯光致异构储能材料在固态膜中的研究方向和应用前景.     

四环庚烷的合成

以低沸点石油醚/丙酮为混合溶剂,芳香酮类化合物为光敏剂,对降冰片二烯异构化生成四环庚烷的反应进行了研究。考察了反应物初始浓度、光敏剂的用量及种类和时间对此反应的影响,得到四环庚烷合成的最佳工艺条件:室温下,初始浓度1.0 mol·L-1,6%二苯甲酮为光敏剂,紫外光照反应15 h,可获得93%转化率和100%选择性。反应液经减压蒸馏即可获得高纯度的四环庚烷燃料(73%收率,95%纯度)。     

Ultrafast Photoconversion Dynamics of the Knotless Phytochrome SynCph2

The family of phytochrome photoreceptors contains proteins with different domain architectures and spectral properties. Knotless phytochromes are one of the three main subgroups classified by their distinct lack of the PAS domain in their photosensory core module, which is in contrast to the canonical PAS-GAF-PHY array. Despite intensive research on the ultrafast photodynamics of phytochromes, little is known about the primary kinetics in knotless phytochromes. Here, we present the ultrafast P_r ⇆ P_fr photodynamics of SynCph2, the best-known knotless phytochrome. Our results show that the excited state lifetime of P_r* (~200 ps) is similar to bacteriophytochromes, but much longer than in most canonical phytochromes. We assign the slow P_r* kinetics to relaxation processes of the chromophore-binding pocket that controls the bilin chromophore’s isomerization step. The P_fr photoconversion dynamics starts with a faster excited state relaxation than in canonical phytochromes, but, despite the differences in the respective domain architectures, proceeds via similar ground state intermediate steps up to Meta-F. Based on our observations, we propose that the kinetic features and overall dynamics of the ultrafast photoreaction are determined to a great extent by the geometrical context (i.e., available space and flexibility) within the binding pocket, while the general reaction steps following the photoexcitation are most likely conserved among the red/far-red phytochromes.     

胡椒碱的光异构化研究

为探索胡椒碱的光致异构化规律,以纯胡椒碱为原料,采用不同辐照时间、辐照波长、光源等处理,HPLC检测胡椒碱及其3种异构体。结果表明:(1)辐照一定时间后,胡椒碱及其异构体相互转化并形成动态平衡;(2)365 nm紫外辐照对胡椒碱异构化的影响大于254 nm辐照;(3)不同光源处理时胡椒碱的损耗量相近,紫外辐照利于异胡椒碱和胡椒脂碱形成,日光灯照射利于异胡椒脂碱形成。     

Chemical protection of pheromones containing an internal conjugated diene system from isomerization and oxidation

Conjugated diene systems are common in natural products, including pheromones. The systems are sensitive to heat, light, and oxygen, among other things. They can be protected by antioxidants and UV absorbers, which slow downcis-trans isomerization and oxidation. Three sex pheromones (one as an analog) containingZ,E, E,Z, andE,E units were studied: (Z,E)-9,11-C₁₄OAc, (E,Z)-7,9-C₁₂OAc, and (E,E)-10,12-C₁₆OAc. The UV absorber 2-hydroxy-4-methoxybenzophenone and the antioxidants BHT and BHA were found to be effective in solution. The protective effect of the UV absorber against photoisomerization on paper carriers was not as good as that in solution. Preliminary studies on the utilization of formulations containing these compounds and (Z,E)-9,11-C₁₄OAc in the mass trapping of Egyptian cotton leafworm male in cotton fields showed the new combinations to be as good as a previously used formulation with UOP 688, a compound which is unpleasant to handle.