| The design and synthesis of novelπ-conjugated systems with unique optic-electronic properties have attracted increasing attention due to their potential applications in solar cell, organic light-emitting diodes (OLEDs), sensors, field-effect transistors, etc. It has been well-known that carbazole is a conjugated heterocyclic compound bearing electron-rich nitrogen heteroatom. It can be used as hole-transporting and luminescence material. Meanwhile, the planar configuration of carbazole is favorable for forming ordered arrangement viaπ-πinteraction. Herein, we have synthesized a series of novel compounds containing carbazole, including triphenylamine functionalized bis((3-diketone)carbazole and bis(dioxaborine)carbazole derivatives, oligocarbazole functionalized subporphyrins and phosphorus (V) porphyrins. Their self-assembling behaviors and photophysical properties have been studied. Some creative results have been obtained, and the main results are outlined as following:(1) A series of new triphenylamine functionalized bis((3-diketone)s bridged by carbazole (CnBDKC, n= 1.4,8,16) have been synthesized, and their self-assembling as well as photophisical properties were investigated. It is found that the length of carbon chains has significant effect on their self-assembling properties. Well-defined 1D nanowires were easily generated from C1BDKC with a methyl directed byπ-stacking interaction, and the molecules packed into J-aggregates in the nanowires. 1D nanofibers based on C16BDKC bearing a long chain of hexadecyl were prepared through the organogelation process, and H-aggregates were formed driven by the synergistic effect ofπ-stacking interaction as well as van der Walls force in gel phase. Notably, the obtained 1D nanostructures can emit strong green light under irradiation, suggesting that these 1D nanomaterials may possess potential applications in emitting materials as well as photonic devices.(2) New triphenylamine functionalized bis(dioxaborine)carbazole derivatives (BDOBCn, n=4,8,16) have been synthesized, and low-dimensional fluorescent nanostructures with different morphologies have been fabricated from BDOBCn with carbon chains in different length. 1D nanowires and amorphous nanoparticles are generated from BDOBC4 and BDOBC8 via reprecipitation approach, respectively. 1D nanofibers based on BDOBC16 are prepared through organogelation process. The films formed from the obtained nanostructures can act as efficient fluorescent chemosensors for probing aniline vapor with different response rate and different sensitivity controlled by their morphologies. The mesh-like film obtained from BDOBC16-based gel exhibits faster response and higher sensitivity than the nanoparticle and nanowire-based films, the response time and the detection limit are 0.67 s and 8.6 ppm, respectively. The reason is that the mesh-like nanofiber-based film not only provides a large specific surface for enhanced adsorption and accumulation of gaseous molecules, but also enables expedient cross-film diffusion of gaseous species. It provides a strategy to manipulate the morphology of organic nanostructures with desired functionality.(3) A series of new styrene functionalized bis(β-diketone)s bridged by carbazole and phenothiazine have been synthesized. It is found that the length of the carbon chains, the structures of the bridging unit and the linked site of the chromophore have significant effect on the self-assembly. For example, the compounds connected by 2,7-carbazole exhibited good gel ability, which would not influenced by the length of carbon chains. As to the compounds linked by 3,6-carbazole, only the one bearing long carbon chain could form the gel, and its gel ability was very bad. The compound connected by 3,7-phenothiazine only bearing short carbon chain could form the gel. Notably, the obtained gel nanofibers can emit strong fluorescence, suggesting that these 1D nanomaterials may possess potential applications in emitting materials and sensors.(4) A series of (3-diketone and dioxaborine derivatives containing triphenylamine bridged by carbazole, phenothiazine and fluorene have been synthesized. It was found that the structures of the bridged units, linked sites and complexing with boron had effect on the two-photon absorption cross-section. It suggested that the two-photon absorption cross-section would increase with increasing the conjugation of the compound, the pushing electron ability of the bridging group and the withdrawing electron ability ofβ-diketone. For example, the two-photon absorption cross section of the obtained compounds increased from 205 to 2530 GM by adjusting the above mentioned factors. It provides a strategy to design functional organic molecules with large two-photon absorption cross section. (5) A series of novel star-shaped subporphyrins functionalized with three monodisperse oligocarbazole arms T(OCAn)SubPs were synthesized. The photophysical investigation indicated an efficient photo-induced energy transfer occurred from the oligocarbazole arms to the subporphyrin core, and the efficiency of the energy transfer decreased with increasing the number of carbazole units. Such energy transfer was in accordance with Forster mechanism. In addition, these star-shaped subporphyrins can emit intense yellow-green light, and might become candidates for optical materials.(6) Phosphorus (Ⅴ) porphyrins with six monodisperse well-defined linear oligocarbazoles at axial and meso- positions of the porphyrin core have been designed and synthesized. Among these macromolecules, the phosphorus (Ⅴ) porphyrin core could be shielded by the six oligocarbazole arms, so theπ-πinteractions between the porphyrin core could be suppressed efficiently. The effective site-isolation effect also resulted in good solubility and good film-formation ability of the branched porphyrins. The photophysical investigation indicated that these compouds were non-fluorescence, which might originated from the occurrence of photoinduced intramolecular electron transfer (or accompanying with the photoinduced intramolecular energy transfer). Therefore, these branched macromolecules might find application in photovoltaic cells.
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