Synthesis, Photoelectric Properties And Theoretical Investigation Of Oligomeric P-phenylene Vinylene Derivatives

With the arrival of information society, functional molecular materials impulse and sustain the progress of information high technique. It has become one of the hotspot areas of research in recent years. Although chemists have synthesized thousands upon thousands compounds through practice for a long time, people are expecting a suit of scientific methods to decrease the blindness of material research and increase the theory forecast with the requirement of new material. Because the function of macro system is the exhibition of micro molecular's property, array and assembly of micro molecular would affect the function of macro system greatly. So probing it's electronic structure and bonding law from theory and confirming it's space structure and bonding way from experiment are the important aspects of these research areas.The most parts of the thesis as follows:1. Several organic functional molecular compounds with different electron-releasing groups or electron-withdrawing groups which could be used to prepare electroluminescence device were designed and synthesized using oligomeric p-phenylene vinylene as framework. Their structures were characterized by ¹H NMR, IR, MS, ¹³C NMR.2. Their UV spectra and fluorescence spectra have been studied. The results shows that they have high fluorescence quantum efficiency and their photoluminescence are different with different substituent groups or with different length of conjugated chain. We can conclude that they have good stability from systemic investigation.3. Organic electroluminescence devices were prepared using the new compounds with no electron transporting layer. The capability of electroluminescence was researched and their threshold voltages were between 3-5 V. It can be concluded that these compounds have good electron transporting property while they luminesce.4. Using quantum chemistry methods, the geometries of eleven compounds' ground states and excited states were optimized, their molecular orbit components were analyzed and discussed the effects of different substituent groups on molecular property. All calculations were carried out using the Gaussian 98 quantum chemistry program. In addition, the absorption spectrum and emission spectrum of these compounds were calculated using TD-DFT methods and analyzed the mechanism of luminescence and electron transition. New compounds with pyridazine in oligomeric phenylene vinylene's main chain were designed. Theoretical investigation of their absorption spectrum and emission spectrum were carried out and results showed that they have electroluminescence capability.5. Electron property and isomerization reaction of pyridazine derivatives which were organic functional molecules were researched employing ab initio HF and (DFT)/B3LYP. Reagent intermediates and transition states in every reaction channel were obtained. Through comparing the stability of intermediates and the structure change of isomerization process, the best reaction pathway was affirmed and explained the experiment results reasonably.