新型三维有序卟啉复合薄膜的设计、自导向组装及其光电性能

This project is carried out according to self-directed assembly and photoelectronic property of three-dimensional porphyrin composite thin films. Several serials of new types of metalloporphyrin monomers modified with sisesquioxane(spacer length is tunable) are prepared, and the monomers can self-directedly assemble in three-dimensional directions. In the process of self-directed assembly of the porphyrin composite thin films, the central metal ion of porphyrin macrocycle coordinates with conjugate bidentate-bridged ligand in axial direction, and forms an axially ordered porphyrin oligomer in one step. Then the oligomer is transferred onto a moist substrate and further self-directedly assembles in the horizontal direction by the hydrolysis-polymerization of sisesquioxanes linking on the periphery of porphyrin microcyle. Consequently, the three-dimensionally ordered porphyrin composite thin films can be achieved on various substrates by the simple process. The composite thin film possesses tunable interlayer spacing and thickness (by controlling the size and the quantity of the conjugate bidentate-bridged ligand), stable and high photoelctronic transformation efficiency. The conditions of self-directed assembly of porphyrin monomer in three-dimensional directions are explored by structure characterization and property measurement. The influence of self-directed assembly behavior of the monomer in three-dimensional directions on the microstructure, morphology and photoelectric property of the composite thin films is revealed. Furthermore, the mechanisms of self-directed assembly and photoelectronic property produced are clarifed. It provides a new thought and a new method to prepare the composite thin films with special functions.

本项目主要围绕三维有序卟啉复合物薄膜的自导向组装及其光电性能研究为主线展开，制备系列能在三维方向自导向组装的笼形倍半硅氧烷修饰的新型金属卟啉单体。利用卟啉单体自身的结构特点，经共轭双齿桥联配体诱导，促使单体定向排列并以配位键(轴向，卟啉环中心的金属离子与桥联配体配位)和共价键(水平方向，卟啉周边硅氧烷的水解-聚合)为主要推动力进行自导向组装形成溶胶，通过自旋涂覆到基片上的溶胶的凝胶化实现卟啉单体在三维方向的有序组装，获得层间距和层数可控(调节桥联配体的量和尺寸)、稳定且光电性能优越的三维有序的卟啉复合物薄膜。 通过系统地结构表征和性能测试，摸索出卟啉单体在三维方向自导向组装的条件，深入研究单体的组装机理，进而揭示单体在三维方向的组装行为对复合薄膜的微观结构、形貌和性能的影响，阐明其光电活性产生的机制。为有目的地设计和开发结构新颖、性能优异的光电器件提供理论指导和崭新的思路。

如何设计结构单元并通过简单的过程构筑稳定且性能优异的三维有序薄膜是其在光电器件、传感和燃料电池电极领域应用需要解决的关键问题之一。金属卟啉的结构易于调制而且具有较高的热稳定性和化学稳定性，以金属卟啉分子作为结构单元构建MOFs薄膜，能更加精细地调控MOFs薄膜的结构并丰富其性能。在本项目中，我们设计、合成了多种能在三维方向自导向组装的笼形倍半硅氧烷修饰的新型金属卟啉单体。利用卟啉单体自身的结构特点，经共轭双齿桥联配体诱导，构筑了多种稳定、有序的卟啉复合物薄膜，进而研究了其结构和性能之间的关系。主要研究内容如下：. 1 新型金属卟啉单体的合成和表征：. 将四羧基苯基卟啉钴、铁等分别酰氯化、硅烷化，合成出具有轴向配位能力和水平方向水解聚合能力的新型卟啉单体。另外，利用四羟基苯基金属卟啉与γ-异氰酸丙基三乙氧基硅烷为反应物，通过卟啉中心金属离子和异氰酸根的氮原子轴向配位和在水平方向发生亲核加成反应制备五种新型卟啉单体。通过紫外可见光谱、红外光谱、核磁共振谱和质谱等对所得产物组成和结构进行表征。. 2 卟啉MOFs薄膜的自导向组装和性能研究：.分别以4, 4联吡啶、吡啶炔、吡啶基卟啉等为桥连配体，自导向组装了三种有序的卟啉MOFs薄膜。通过系统地结构表征和性能测试，详细研究了配体的分子长度、共轭性能和稳定性等对卟啉MOFs薄膜的微观结构、形貌和光电性能的影响。结果表明：得到的卟啉MOFs薄膜具有介孔结构、热稳定性较高；4, 4联吡啶与卟啉环中心的钴离子的轴向配位保证了卟啉单体在轴向上有序组装，同时有效促进了电子转移，使获得的有序卟啉MOFs薄膜具有更高的光电响应和稳定性。. 3 卟啉MOFs的光催化制氢性能研究. 研究了卟啉MOFs的光催化制氢性能，进而探讨了卟啉环中心金属离子对卟啉MOFs光催化还原水制氢性能的影响。. 4 探索了卟啉与石墨烯的组装和性能。 . 本项目中涉及的卟啉MOFs薄膜制备过程简单、方法新颖，而且获得的产物稳定，光电性能和光催化制氢活性较高，这为其它卟啉组装体的制备和性能研究提供了新的思路。