OBHPV共軛分子之合成及其自組裝性質結構之探討

Abstract

在這篇研究中，我們成功合成出兩種π-共軛分子，OBHPV3和OBHPV4。這兩種分子可溶於正己烷、正癸烷和三氯甲烷，因此可用紫外光-可見光及光致放光圖譜來研究其溶液態的光學性質。OBHPV3和OBHPV4溶液的吸收強度隨著濃度的增加而增加，而PL圖譜呈現紅位移的現象，這是和超分子結構的形成有關：超過10-5 M在OBHPV3和OBHPV4圖譜強度上開始轉變。我們用原子力顯微鏡(AFM)來偵測其沉降在雲母片上固體狀態的結構。OBHPV3系統在10-4 M正己烷溶液沉降，我們發現有許多管狀的結構，其寬為30 nm，長度為數百奈米；在10-5 M正癸烷溶液沉降，發現有長幾微米、寬幾十奈米長條狀的結構形成；在10-4 M三氯甲烷溶液中沉降，我們發現許多像針狀的薄片，其寬為20 ~ 30 nm，這些針狀薄片可以聚集成類似伸長的繩子一樣，但從TEM圖可以看到由這些薄片可堆疊出許多大大小小像編織的花環的結構。OBHPV4的系統中，由於OBHPV4分子具有不對稱性，所以OBHPV4在這些溶劑當中沒有很明確的結構產生。但從正己烷溶液中沉降，可分辨出有微胞狀帶孔的結構，其直徑大小為30 nm左右。我們提出組成這些結構的驅動力包含有π-π作用力、氫鍵力、以及凡得瓦力。

In this research, we have successfully synthesized two π-conjugated molecules, OBHPV3 and OBHPV4, which were able to dissolve in hexane, decane, and chloroform. Their optical properties were investigated by UV-Visible and photoluminescence (PL) spectra. It was observed that the absorption of OBHPV3 and OBHPV4 solutions increased with increasing concentrations. However, under high concentrations, PL spectra showed red-shifted associated with the formation of supramolecular architectures. The turning points for OBHPV3 and OBHPV4 were revealed above ~ 10-5 M. Solid state architectures deposited on mica were monitored by atomic force microscopy (AFM). In OBHPV3 system, the tubular features with ~ 30 nm in width and several hundred nanometers in length at ~ 10-4 M in hexane were found. In decane, long stripes with several micron-meters in length and 10 nm in width were found at ~ 10-5 M. In chloroform, needle-like flakes with 20 ~ 30 nm in width could aggregate into elongated ropes at ~ 10-4 M. Interestingly, we also observed from TEM images many laurel wreaths formed by aggregation of these small flakes. For OBHPV4 system, due to the asymmetric structure of OBHPV4 molecule, no well-defined features were observed in most solutions except hexane, by which vesicle-like texture with a diameter of 40~50 nm containing holes were discerned. It is believed that the driving forces for all above self-assembly processes were the combination of π-π interaction, hydrogen bonding, and Van der Waal interaction.