| 5, 12-Dihydro-quino[2, 3-b]acridone-7, 14-dione, generally has been named quinacridone (or abbreviated as QA). Quinacridone (Pigment Violet 19) is the most important pigment for orange-violet shades that display excellent fastness properties, including high melting temperature, excellent optical, physical and chemical stability. Over the past decades, quinacridone and its derivatives have been investigated and known more and more, which application including dye and pigments, crystal engineering, photoelectric devices, biology probe, metal ionic sensor and supramolecular tunable self-assembly etc. Especially, high photoluminescent efficiency in dilute solution combined with good electrochemical stability in the solid state has allowed the fabrication of high performance OLEDs based on QA. A great deal of effort has been invested in optimization of QA based devices in terms of efficiency and lifetime. Some studies on QA have been devoted to investigate the assembly and structure properties of this class pigments. The phase-formation behavior and aggregation properties of some soluble quinacridones have been carefully studied. Quinacridone derivatives with alkyl chains have been synthesized and used in Langmuir-Blodgett films to control the orientation and packing of the chromophores. For quinacridone and derivatives, substituents could efficiently inhibit the aggregation and self-absorption between core molecules in the solid state.Moreover, to fully exploit the potential applications of this kind of functional compound in organic materials based devices, it is necessary to design and synthesize some novel QA derivatives with different molecular structures and to understand the relationship between molecular structures and aggregation, film formation, optical and electronic properties in solution and condensed states. These will enable the development of new strategies for the preparations of high performance organic optical and electronic materials. Furthermore, controlling self-quenching and aggregation property, and in turn achieving desirable performance in devices remain a challenge for QA derivatives. Our studies mainly focus on the four aspects:1. In this thesis, we report the design, synthesis and characterizations of four series including 18 quinacridone derivatives bearing different substitutes. The detail 1H NMR, mass spectra, elements analyses and crystal structures have been present. These data could help us understand the relationship between the molecular aggregation characteristics and the optical properties of the compounds.2. UV-vis absorption and emission spectra and photoluminescent quantum yields of all of title compounds in solution at different concentration have been measured. These results demonstrated that spectroscopic properties of all of synthesized quinacridone derivatives in solutions exhibit concentration-dependent features, which are resulted in aggregation behavior, especially "face-to-face" aggregation. However, the steric hindrances of substituent group efficiently influence the fashion and degree of aggregated state. The concentration-dependent absorption spectra demonstrate that these alkyl/dendritic quinacridone derivatives are nearly unaggregated within the concentration range of 6.0×10-6 to 1.0×10-3 M. In contrast with alkyl quinacridone, the second generation dendritic-substituted quinacridone displays nearly unaggregated property and higher PL efficiency at solution, even in solid state. Especially, PL quantum yields of G2DBQA in dilute solution (3×10-6 to 6×10-5 M) are approach 100%It is worthwhile to mention that the critical concentration (6.0×10-4 M) of G2DBQA, at which emission intensity begins to drop significantly, is obviously higher than that (6.0×10-5 M) of alkyl quinacridones. These results demonstrated that molecular packing properties have dramatic effect on the PL properties of solid thin films and it is possible to optimize the PL and EL properties of quinacridone derivatives through the regulation of molecular structure and aggregation feature.3. On the other hand, quinacridone derivatives have been exploited as charge-transport materials in the fields of photovoltaic devices and organic field-effect transistor etc., because the kind of compounds naturally possesses organic semiconductivity. For organic semiconductivity materials, charge-transport property is necessary and has been improved by stronger intermolecular non-covalent interactions. So, our work also focuses on the self-assembly of organic nanocrystals (or nanoparticles) based on quinacridone derivatives.A series of quinacridone derivatives CnTMQA (n = 6, 10, 14, 22) have been employed, as building block to fabricate organic 1-D luminescent nano- and microwires based on the reprecipitation and evaporation approaches, respectively. CnTMQA compounds with rigid conjugated core exhibit stronger tendency to form 1 -D structure compared.(1) The 1-D nanocrystals exhibit different morphology features, which are dependent on length of alkyl chains on building block. C6TMQA have formed the rod-like nanowires, with width of 80 nm and length of 1 -2μm, respectively. After a long time aging these rod-like nanocrystals aggregated to form some diamond-like microcrystals; For C10TMQA and C14TMQA, the ribbon-like wires with length of around severalμm, width of 200 nm and 2-3μm, respectively; and the C22TMQA failed to form 1-D architectures.(2) The luminescent properties are dependent on the size and structure of nanocrystals. The solution, wires and crystals of C10TMQA represent the different aggregation states of C10TMQA molecules, respectively, i.e. monomer, mesoscale (nano- to micrometer) and bulk states, so which should exhibit 74 nm red-shifts.(3) Additionally, we have used C10Ar as guest building block to co-self-assembly with C10TMQA, and successfully fabricated light-emitting 1-D rod-like (40 nm×100 nm×1μm) and ribbon-like (width 1-2μm and long several tensμm) nanocrystals. It is interesting that energy-transfer likely exists in the binary self-assemble architecture.4. A novel quinacridone derivative bearing dendritically group, G2DBQA was exploited as a simple building block to fabricate nano/microscale particles with various morphologies and sizes. By the reprecipitation and solution evaporation, the spherical nano/microparticles with width 0.5～2 urn and hierarchical actinia-like microcrystal have been fabricated, respectively. Spectra data, powder XRD patterns, optimized molecular model suggested that, different stacking constructions lead the two distinct morphologies.In conclusions, we have designed and synthesized 18 quinacridone derivatives and obtained single crystals of 5 compounds. For these compounds, the aggregation, optical properties and low-dimensional self-assemble characters are tunable by modification of multiple substituents. These results elucidated the relationships between molecular structures/molecular packing structures and physical chemistry properties of materials.
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