Synthesis, Properties, and Applications of New Two-Photon Absorption Molecules
| Autor: | Jian-Zhang Cheng, 程健彰 |
|---|---|
| Rok vydání: | 2013 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 101 Two-photon absorption (TPA) process is a nonlinear absorption process involving the simultaneous absorption of two photons. Recently, TPA chromophore has attracted considerable attention in many research fields owing to its wide practical applications such as three-dimensional optical data storage, microfabrication, two-photon fluorescence microscopy, optical limiting and photodynamic therapy. Chromophoreswith high capability of TPA are desired for all these applications because a greater degree of excitation can be achieved with lower laser intensity. Thus, in order to shed light onto the design of molecules for increasing the TPA cross section and for tuning the position of the two-photon absorption peak wavelength, there is an urgent need to unveil the structure-propertyrelationship for two-photon absorbing molecules. This thesis is composed of three major parts. For the first part, we have successfully synthesized a series of new quadrupolar molecules with various donors and acceptors which were bridged with a fluorene conjugation. The donors, mainly diaryl amino group was introduced onto the C2 of fluorene core employing palladium-catalyzed C-N bond coupling reaction. The resulting donor-equipped intermediate was connected to the acceptors such as dicyanobenzene and benzothiadiazole by employing Suzuki coupling reaction to afford new TPA chromophores Fl-DCB (=1620 GM by z-scan) and Fl-BTD (= 623 GM by z-scan), respectively. We also successfully synthesized water-soluble TPA molecules Fl-DCB-TMA4 and Fl-BTD-TMA4 by introducing trimethylaminium bromide group onto the long alkyl chains at C9 of fluorene core. The water-soluble molecue (Fl-BTD-TMA4) was found to have biocompatibility by flow cytometry analysis and confirmed the dye molecules can enter HeLa cells after 4 hours observed by fluorescence microscope. The amphiphlic behavior of ionic group end-capping water-soluble has interesting propensity of self-assembling into interesting nano structures under different solvents. In addition, we utilized the structural blocks to synthesize a TPA derivative azide-BTA which can apply to give nanoparticles in water solution and performed electrogenerated chemiluminescence (ECL). Our previous studying pointed out that the new donor-acceptor molecule (DAF) has great singlet oxygen generation quantam yield (> 100% as compared to that of standard H2TPP). In the second part of this thesis, we introduced oligoethylene glycol side chains and trimethylammonium bromide end-capped side chains on the diarylamine of DAF to for increasing the water solubility to give new DAF-based molecules EDAF, DAF-TMA2, and DAF-TMA4. Among them, we found the water-solubility of DAF-TMA4 (40 mg/mL) was increased by thirteen thousand times as compared to that of parent DAF (3 g/mL). We then used flow cytometry to study the biocompatibility of DAF-TMA2 and utilized fluorescence microscope to confirm the dyes can enter HeLa cells after half an hour. We also synthesized phenanthraquinone-based derivatives DAPQ and EDAPQ to compare with fluorenone-based derivatives. We found the singlet oxygen generation quantum yield of DAF-TMA4is better than those of other fluorenone-based or phenanthraquinone-based derivatives. All of our new fluorenone-based or phenanthraquinone-based derivatives were found to give small TPA cross-section |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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