Synthesis And Properties Of Stucture-Controllable Porphvrin/Porphyrin-Reduced Graphene Oxide Assemblies

For the two-dimensional structure and excellent physicochemical properties, graphene has showed potential applications in varies fields. However, due to the π-π interaction, graphene with the layer structure is prone to aggregate, which will limit its applications. In order to prevent graphene from aggregating and improve its physicochemical properties, researchers take more attentions to the functionalization of graphene. Porphyrins, a class of multifunctional π-conjugated molecules, could be used to modify graphene sheets, which can inhibit graphene from aggregating and integrate the excellent properties of graphene and porphyrin. In addition, by means of self-directed assembly of the porphyrin monomer with special structure, the fast and facial fabrication of highly oriented porphyrin metal-organic framework (MOFs) with excellent performance would provide theoretical basis for the applications in photoelectric device, membrane electrode and battery. In view of the above considerations, the major contents in this thesis are carried out as follows.5,10,15,20-Tetrakis(4-trimethylaminophenyl) porphyrin iodide (TAPPI) was assembled facilely on the surface of the graphene oxide (GO) coated polystyrene (PS) microspheres by electrostatic interaction combined with n-n interaction. The monodisperse ternary composite with core-shell structure (PS microspheres/GO/TAPPI) was characterized by transmission electron microscopy, Raman spectrum and solid diffuse reflectance UV-visible spectra. When TAPPI was assembled on the surface of the PS microspheres/GO, effective electron transfer from the excited TAPPI to the GO can be achieved as evidenced by fluorescence spectra. Moreover, compared with that of pure TAPPI, TAPPI molecules in the ternary composite displayed high UV stability and thermal stability.By layer-by-layer self-assembly method, reduced graphene oxide (RGO)-based composite films with highly photoelectronic activity were assembled with 5,10,15, 20-tetrakis (p-N, N, N-trimethylanilinium) porphyrin tetraiodide (TAPPI) and copper sulfophthalocyanine (CuTsPc) as the co-sensitizers. The π-π interaction and electrostatic interaction were the main driving forces of the assembly. The linear dependence of the absorption on the layer numbers of the films demonstrated the formation of the ordered films. In the composite film, an efficient photoinduced electron transfer can take place as evidenced by fluorescence spectra. Furthermore, the photoelectronic response for the RGO/TAPPI/CuTsPc film was higher than that of the RGO/TAPPI film, the RGO/CuTsPc film or the TAPPI/CuTsPc film. The complemental absorption spectra of TAPPI and CuTsPc and the quick transfer of photoproduced electrons could be the main reasons for the enhanced photoelectronic response in the RGO/TAPPI/CuTsPc films.A new type of metalloporphyrin iron (Ⅲ) monomer modified with sisesquioxane was prepared. A facile approach for preparing highly oriented porphyrin MOFs was explored by employing self-directed assembly of silanized porphyrin iron (Ⅲ) monomer. In the process of self-directed assembly of the metalloporphyrin iron (Ⅲ) monomer, the central iron (Ⅲ) of porphyrin macrocycle coordinated with bipyridine (bpy) in axial direction, and further self-directedly assembled in the horizontal direction by the hydrolysis-polymerization of sisesquioxanes linking on the periphery of metalloporphyrin iron (Ⅲ) monomer. The self-directed assembly of porphyrin iron (Ⅲ) monomer in three-dimensional directions and photoelectronic property were 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 porphyrin MOFs was also revealed.