雙羰基五苯荑衍生物之分子轉輪合成與性質研究

Synthesis and Characterization of Dicarbonyl Pentiptycene-Derived Molecular Rotors

曾婷(Ting Tseng)

指導教授 ： 楊吉水

國立臺灣大學/理學院/化學研究所/碩士(2012年)

https://doi.org/10.6342/NTU.2012.10238

摘要

本論文主要是在合成與探討新型的五苯荑衍生之分子轉輪，利用五苯荑分子作為定子，在二邊各接上一個羰基的轉輪作為一雙轉輪系統。我們建立了DBP-CF3和DBP-3Me兩個立體效應不同的雙羰基五苯荑分子，透過變溫1H和13C NMR圖譜，藉由電腦的模擬計算，可得到相對應的旋轉動力學參數。
我們可經由NMR實驗得到DBP-CF3之含CF3芳香環連接羰基單鍵（Ar-CO）的轉速及兩轉輪為順反式異構物的交換速率，並推論出順反交換速率等於五苯荑連接羰基單鍵（PT-CO）鍵旋轉之轉速，因此可間接得到PT-CO鍵之旋轉速率。因Ar-CO旋轉能障較PT-CO小，我們可推論此分子的芳香環對於五苯荑是進行獨立的旋轉。而DBP-3Me是嘗試設計能進行齒輪般的旋轉的分子，其旋轉能障極小而無法藉由實驗量測其轉速，與預測一致，因此以理論計算證實其運動模式。
DBP-CF3及DBP-3Me皆具有可逆的氧化還原能力，透過光譜電化學及化學還原NMR光譜的測量，DBP-CF3在其第二還原態時為雙自由基陰離子態，而DBP-3Me在其第二還原態時為雙陰離子態。此分子有潛力做為以電化學控制其轉速的雙轉輪分子齒輪。

關鍵字

分子機械 ； 分子轉輪 ； 分子齒輪 ； 電化學

並列摘要

This thesis reports the synthesis and properties of new pentiptycene derivatives as new type of molecular rotors, which consist of one pentiptycene stator and two carbonyl rotors. Depending on the carbonyl groups, they are designated as DBP-CF3 and DBP-3Me. We have used variable-temperature 1H and 13C NMR spectroscopy to probe the rotation kinetics of the rotors.
The rotation rate of Ar-CO bond and the interchange rate of syn-anti form in DBP-CF3 are obtained from line-shape analysis. We assume that the rotation rate of PT-CO bond is equal to the interchange rate of syn-anti form, so we can indirectly obtain the rotation rate of PT-CO bond. Because the rotation barrier of Ar-CO bond is lower than PT-CO bond, we can assume that the aryl group in DBP-CF3 independently rotate with pentiptycene group. We attempt to design DBP-3Me as a molecular gear. The rotation barrier is too low to be measured by VT-NMR experiment, so we confirm the rotation mode by DFT calculations.
The reducted forms of DBP-CF3 and DBP-3Me are electrochemically stable, which facilitates spectroelectrochemical and chemical reduction NMR spectrum measurement. It is a diradical anion character for DBP-CF3, but it is a dianion character for DBP-3Me at the second reduction potential. They are potential redox-active molecular machine.

並列關鍵字

molecular machine ； molecular rotors ； moleculae gears ； electrochemistry

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