Title: 偶氮Calix[4]arenes的合成與其光誘導及熱化學順反異構化研究
Synthesis of Azo-calix[4]arenes and their Photoinduced and Thermal cis-trans isomerization
Authors: 王瓊萩
Chiung Chiu Wang
Wen-Sheng Chung
Keywords: 偶氮;順反異構化;活化能;azo-calix[4]arene;cis-trans isomerization;activation energy
Issue Date: 2000
Abstract: 偶氮Calix[4]arenes的合成與其光誘導及熱化學順反異構化研究 學 生:王 瓊 萩 指導教授:鍾文聖博士 國立交通大學應用化學研究所 摘 要 本論文中我們合成一系列偶氮calix[4]arenes,包含上緣含有丙烯基或羥基及具有推拉電子基的雙偶氮、單偶氮calix[4]arenes和下緣有四酯基取代的偶氮calix[4]arenes,並進行其光誘導與熱化學之順反異構化研究。我們利用UV/Vis吸收光譜來記錄經350 nm的光照射後的偶氮calix[4]arenes之順式轉換成反式的變化情形,並由一級反應方程式算出順反異構化速率kct。我們發現下緣有四酯基取代之偶氮calix[4]arenes 35b、35d及36d的kct值為2.3-3.3 × 10-3sec-1,比下緣無取代的偶氮calix[4]arenes 33a-d、34a-d、39a-c及40a的kct值(53-369 × 10-3sec-1)小。經由變溫下量測的kct以及利用阿瑞尼士方程式,可以求出順反異構化的活化能(Eact),其值介於1.7-10.1 kcal mol-1之間,比偶氮高分子和peptides的Eact(16-22 kcal mol-1)小。本論文將探討於1,4-環氧己烷和氯仿兩種溶劑下,影響偶氮calix[4]arenes 之UV/Vis吸收光譜、kct及 Eact的原因。
Synthesis of Azo-calix[4]arenes and their Photoinduced and Thermal cis-trans isomerization Student: Chiung-Chiu Wang Advisor: Dr. Wen-Sheng Chung The Department of Applied Chemistry National Chiao Tung University Abstract In this work, a serises of azo-calix[4]arenes including mono- and 1,3-diazocalix[4]arenes derivative are synthesized and their photoinduced (trans to cis) and themal (cis to trans) isomerization are studied. After being irradiated with 350 nm UV light for various time (2-5 min), the samples were monitored with a time dependent UV/Vis spectra. The rates in isomerization from cis to trans for these azo-calix[4]arenes were found to follow the first order kinetics. We found that azo-calix[4]arenas, 35b, 35d and 36d, with tetraester substituent in the lower rim have smaller kct (2.3-3.3 × 10-3sec-1) than those without (e.g. compound 33a-d, 34a-d, 39a-c and 40a (53-369 × 10-3sec-1). Arrhenius plots of kct allowed us to estimate the activation energy (Eact) of these azo-calix[4]arenes ; the values are in the range of 1.7-10.1 kcal mol-1. The calculated Eact values for these azo-calix[4]arenes are lower than those for azo-polymers and peptides (16.0-22.0 kcal mol-1). Factors affecting the UV/Vis spectra, kct and Eact of these azo-calix[4]arenes in two different solvents (1,4-dioxane and chloroform) were discussed.
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