請用此 Handle URI 來引用此文件:
http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/73558
標題: | 激發態質子轉移化合物之合成研究與分子儲能材料之合成 Syntheses and Study Toward Excited-State Proton Transfer Molecules and Syntheses of Energy Storage Molecules |
作者: | Fan-Yi Meng 孟繁翌 |
指導教授: | 周必泰 |
關鍵字: | 激發態質子轉移,氫鍵,光致異構化,能量轉移,熱活化延遲熒光, Excited-state proton transfer,Hydrogen bond,Photoisomerization,Energy transfer,Thermally activated delayed fluorescence, |
出版年 : | 2019 |
學位: | 博士 |
摘要: | 第一章,經由七元環分子內氫鍵的N-H激發態質子轉移
包含5-(2-aminobenzylidene)-2,3-dimethyl-3,5-dihydro-4H-imidazol-4-one (o-ABDI) 作為核心發色團,含有分子內N-H氫鍵的一系列化合物被合成以及表征。N-H質子的酸性可以經由氮原子上的不同取代基調整。因取代基拉電子效應的不同,其酸性隨著-H < -COCH3 < -COPh < -Tosyl < -COCF3的順序增加。對甲苯磺酰基和三氟乙酰基衍生物產生超快的,不可逆的激發態質子轉移,因此產生完全的質子轉移放光。連接苯甲酰基和乙酰基的可逆的質子轉移化合物分別產生雙重放光。o-HBDI因酸性最弱,因這一過程是吸熱的,無法發生激發態質子轉移。這一結果表明分子內N-H七元環激發態質子轉移的過程受到質子酸性的控制。對於全部化合物,溶液態的熒光量子效率較低(在二氯甲烷中),但是固態放光比較強(3.2%至47.4%) 第二章,3-Hydroxythioflavone以及sulfone衍生物的合成及激發態質子轉移性質研究 3-Hydroxythioflavone(3-HTF)由二氧化硒氧化合成,其性質同激發態質子轉移的原型分子3-Hydroxyflavone對照。另外,含有sulfone基團的類似物也得到了合成,在這過程中,我們得到了一個含有硒的雜環中間體,并表征之。化合物3-HTF經歷了完全的,超快的激發態質子轉移,其速率常數大於150fs-1,溶於環己烷時,常溫及77K下的放光波長都在590 nm。因為硫原子較低的電負性,3-HTF的放光波長相較於3-hydroxyflavone紅移。Sulfone衍生物無法發生激發態質子轉移,其原因是砜基破壞了雜環片段的方向性,同時減弱了羰基的鹼性。 第三章,利用熱活化延遲熒光的儲能分子的研究 熱活化延遲熒光分子中,最低激發單重態和三重態的能量較為接近,因此可由最低激發單重態吸收或放光來估計三重態能量大小。這一特性可以使熱活化延遲熒光分子作為能量遷移的敏化劑得到應用。基於此,我們報導了連接降冰片二烯片段與phenoxazine–triphenyltriazine (PX-TZ)片段的儲能分子PXTZ-NBD,其吸收可延伸至460nm的可見光區域。當激發PXTZ-NBD時,PXTZ作為敏化劑發生三重態能量遷移,從而導致降冰片二烯異構化為四環烷(QC)進而儲存能量。這種四環烷衍生物可經由加熱或催化的方式回到降冰片二烯結構,并放出能量。PXTZ-NBD到PXTZ-QC的過程能夠提供177千焦每摩爾,或307焦耳每克的能量密度,同時有著比較好的常溫熱穩定性,以及較好的循環穩定性。 Chapter 1. The N-H Type Excited-State Proton Transfer Possessing Seven-Membered Ring Intramolecular Hydrogen Bond A series of compounds bearing 5-(2-aminobenzylidene)-2,3-dimethyl-3,5-dihydro-4H-imidazol-4-one (o-ABDI) as the core chromophore possessing a seven-membered ring N-H type intramolecular hydrogen bond (H-bond) are synthesized and characterized. The acidity of the N-H proton and thus the H-bond strength can be fine-tuned by replacing one of the amino hydrogen atoms by a –R substituent, being increased upon increasing the electron withdrawing strength of -R in the order of -H < -COCH3 < -COPh < -Tosyl < -COCF3. Tosyl and trifluoroacetyl derivatives undergo ultrafast, irreversible excited-state intramolecular proton transfer (ESIPT), resulting in solely the proton-transfer emission in the red. Reversible type of ESIPT and hence dual emissions, consisting of normal and proton-transfer tautomer, is resolved for acetyl and benzyl substituted counterparts. As for the weakest acidity in o-ABDI, ESIPT is prohibited due to its highly endergonic reaction. The results clearly demonstrate the harnessing of ESIPT properties via proton acidity and H-bonding strength in a seven-membered ring intramolecular H-bond system. For all studied compounds the emission quantum yield is weak (~10-3) in dichloromethane but is strong in solid ranging from 3.2% to 47.4 %. Chapter 2. Syntheses and Excited-State Intramolecular Proton Transfer of 3-Hydroxythioflavone and Its Sulfone Analogue 3-hydroxythioflavone (3-HTF) was synthesized by oxidation with selenium dioxide, as contrast with 3-hydroxyflavone, a prototype molecule undergoing excited-state intramolecular proton transfer (ESIPT) reaction. Also achieved were syntheses of 3-HTF sulfone analogue and an interesting sulfonyl selane intermediate with their structures fully characterized. 3-HTF showed an ultrafast ESIPT property, as evidenced by > (150 fs)-1 reaction rate constant as well as exhibiting solely a proton-transfer tautomer emission (590 nm) in cyclohexane at RT and in 77 K solid matrix. The lower electronegativity of sulfur atom in 3-HTF leads to significant red shift of the tautomer emission compared with that of 3-hydroxyflavone. The sulfone analogue showed lack of ESIPT due mainly to the decrease of carbonyl basicity, and break the aromaticity of heterocyclic ring. Chapter 3. Molecular Energy Storage Exploiting Thermally Activated Delayed Fluorescence Molecules exhibiting thermally activated delayed fluorescence (TADF) possess proximal energy level between the lowest lying excited singlet (S1) and triplet (T1) states. Thus, the energy level of their T1 state can be readily assessed once knowing either S0 → S1 absorption or S0 ← S1 emission gap. This benefits application of TADF molecules utilizing the triple state as a sensitizer for energy transfer. On this basis, we report the new concept that utilizes a thermally activated delayed fluorescence (TADF) core phenoxazine–triphenyltriazine (PX-TZ) coupled with norbornadiene (NBD), (1s,4s)-bicyclo[2.2.1]hepta-2,5-diene, to form an efficient energy storage diad PXTZ-NBD. PXTZ-NBD exhibits an optimum absorption that covers the solar spectrum up to 460 nm. Upon exciting PXTZ-NBD, PXTZ serves as a sensitizer to sensitize NBD triplet state via triplet-triplet energy transfer, followed by the conversion of NBD to a quadricyclane system (QC), namely tetracyclo[3.2.0.02,7.04,6]heptane, forming a PXTZ-QC product that is thermally stable but convertible back to PXTZ-NBD promptly via catalytic reaction. The uniqueness lies in that the degree of photo-conversion and thermal-reverse-conversion can be directly monitored by TADF in both intensity and relaxation dynamics. The PXTZ-NBD ↹ PXTZ-QC photo-thermal conversion renders the energy storage densities of 177 kJ/mol with good durability evidenced by negligible side products after five photo-thermal conversion cycles. This generates a TADF based solar-thermal energy storage system, for which optimal (≤ 460 nm) solar energy is harvested. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/73558 |
DOI: | 10.6342/NTU201904066 |
全文授權: | 有償授權 |
顯示於系所單位: | 化學系 |
文件中的檔案:
檔案 | 大小 | 格式 | |
---|---|---|---|
ntu-108-1.pdf 目前未授權公開取用 | 4.98 MB | Adobe PDF |
系統中的文件,除了特別指名其著作權條款之外,均受到著作權保護,並且保留所有的權利。