Photochemical Processes in Molecular Assemblies

分子组装中的光化学过程

• 批准号: 03044013
• 负责人: YAMAZAKI Iwao
• 金额: $ 2.56万
• 依托单位: Hokkaido University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03044013/
• 关键词: Photomovement; Photoreceptors; Photochemical reaction; Picosecond laser; Time-resolved fluorescence; Langmuir-Blodgett films; Energy transfer; Proton release; ピコ秒レ-ザ-; 光分子デバイス; 分子組織体

Photorecepting bioorganisms are characterized by highly efficient and ultrafast photochemical reaction which occur in molecular arrangement of polypeptide networks, On the other hand, such molecular arrangements can be fabricated artificially a Langmuir-Blodgett (LB) multilayer film. One can expect in such artificial molecular systems a highly efficient and fast photochemical reaction likely to those of biological systems.The aim of the present research project is to : (1) analyze the primary photoreaction mechanism in photoreceptors of Stentor coeruleus and Blepharisma japonicum, which show photophobic/phototactic movements, (2) compare the photochemical reaction behaviors between the biological system and the artificial molecular system of LB multilayer films, and finally (3) fabricate artificially functional molecular systems and molecular devices. Results of the present research are summarized as follows :1. Primary photochemical processes in biological photoreceptors Antenna chrom … More oprotein and photonic/electronic signal transducing protein Two kinds of proteins were isolated : The one is photoactive in proton transfer from hypericin to environmental protein, and the other plays a role of light-harvesting antenna.Photochemical reaction rates The photochemical reactivities were investigated for microparticles, isolated chromoproteins and hypericin, by means of a picosecond time-resolved fluorescence spectroscopy. Hypericin isolated from protein is found to be weak in proton release activity, but the phtoactive protein is enhanced in ability of proton release, indicating a significant effect of molecular system including proton donor and acceptor in restricted molecular geometries. The reaction rate of proton release was determined to be 6 ps.2. Artificial molecular fabrication by means of Langmuir-Blodgett multilayers Artificial light-harvesting antenna was prepared by using LB multilayers in which different dye molecules are stacking sequentially. The photonic energy transfers in a specific direction through the multilayers likely to those in biological antenna. A LB monolayer film containing hypericin was prepared and examined the photoreactivities in the monolayer films. Less

感光生物体的特点是在多肽网络的分子排列中发生高效、超快的光化学反应，另一方面，这种分子排列可以人工制造Langmuir-Blodgett（LB）多层膜。人们可以期待这种人工分子系统能够像生物系统一样高效、快速地进行光化学反应。本研究项目的目的是：（1）分析蓝海龟和日本眼睑螈的光感受器的主要光反应机制，这些光感受器表现出畏光/趋光运动，（2）比较生物系统和人工分子系统之间的光化学反应行为 LB多层薄膜的分子系统，最后（3）人工制造功能性分子系统和分子器件。目前的研究结果概括如下： 1．生物光感受器中的主要光化学过程 天线色素蛋白和光子/电子信号转导蛋白 分离出两种蛋白质：一种在从金丝桃素到环境蛋白质的质子转移中具有光活性，另一种则起到光捕获天线的作用。光化学反应速率 研究了分离的微粒的光化学反应性 通过皮秒时间分辨荧光光谱法检测色素蛋白和金丝桃素。从蛋白质中分离的金丝桃素的质子释放活性较弱，但光活性蛋白的质子释放能力增强，表明在受限的分子几何形状中，包括质子供体和受体的分子系统具有显着的作用。质子释放的反应速率测定为6 ps.2。利用 Langmuir-Blodgett 多层材料制造人工分子 人工光捕获天线是通过使用不同染料分子依次堆叠的 LB 多层材料制备的。光子能量通过多层结构以特定方向传输，类似于生物天线中的多层结构。制备含有金丝桃素的LB单层膜并检查单层膜的光反应性。较少的

项目成果

T.YAMAZAKI: "Picosecond fluorescence studies on photochemical reactins of stentorin I and II" Photochem. Photobiol. in press. (1993)

T.YAMAZAKI：“Stentorin I 和 II 光化学反应的皮秒荧光研究”Photochem。

N. Tamai: "Excitation energy relaxation of oxacyanine in Langmuir-Blodgett monolayer films" J. Phys. Chem.96. 6550-6554 (1992)

N. Tamai：“Langmuir-Blodgett 单层薄膜中氧花青的激发能量弛豫”J. Phys。