本論文以收斂形式合成出具有二己氨、二辛氨、己基醇和辛基醇為末端官能基四個系列的樹枝狀分子,其中包括系列一 (C6Gn)2N (n=1,2,3)、系列二 (C8Gn)2N (n=1,2,3)、系列三 (NC6OC6Gn)2N (n=1,2,3)、系列四 (NC8OC8Gn)2N (n=1,2,3)。另一方面利用不同的中心核來合成樹枝狀分子CyCl(C8G2)3、CyCl(C8G3)3、TCA(C8G2)3、TCA(C8G3)3、(C8G3)2DAP、(C8G3)2DAB。在合成步驟上並無保護與去保護動作,可以有效降低合成步驟,提高合成產率,幫助多代數的樹枝狀分子溶於一般有機溶劑,無有機溶劑溶解度的困擾。 由結論得知,此四個系列分子經由偏光顯微鏡紋理圖後,判定出(NC6OC6G2)2N、(NC6OC6G3)2N、(NC8OC8G2)2N和(NC8OC8G3)2N分子具有液晶相,之後再將具有液晶相的化合物用 X-ray 判定構形,與 (C6G2)2N、(C6G3)2N、(C8G2)2N 和 (C8G3)2N 相比改變末端官能基有更好的液晶相產生。 在另一方面改變中心核,所使用的中心核 cyanuric chloride、1,3,5-benzenetricarbonyl trichloride、diaminopropane、diaminobutane,合成出的化合物為CyCl(C8G2)3、CyCl(C8G3)3、TCA(C8G2)3、TCA(C8G3)3、(C8G3)2DAP、(C8G3)2DAB,由於不同中心核所導致外圍的 dendrons 排列也有些不同,而產生的液晶也有所不同,有產生液晶相的分別為CyCl(C8G2)3、CyCl(C8G3)3、TCA(C8G3)3、(C8G3)2DAP、(C8G3)2DAB,相較於 piperazine 要來的好。
Four series of triazine-based dendrimers with different peripheral functional groups have been prepared by convergent approach including (C6Gn)2N (n=1,2,3), (C8Gn)2N (n=1,2,3), (NC6OC6Gn)2N (n=1,2,3), and (NC8OC8Gn)2N (n=1,2,3). Also, we use different central core to prepare dendrimers CyCl(C8G2)3, CyCl(C8G3)3, TCA(C8G2)3, TCA(C8G3)3, (C8G3)2DAP, (C8G3)2DAB. These dendrimers were obtained in good yields efficiently because no protected and deprotected processes were needed in the synthesis. They also have good solubility owing to long chain alkyl group on peripheral parts. Based on the DSC and POM investigations, the (NC6OC6G2)2N, (NC6OC6G3)2N, (NC8OC8G2)2N, and (NC8OC8G3)2N series of dendrimers show liquid crystalline phases. Some of them were further confirmed by powder X-ray study. We found that dendrimers (NC6OC6Gn)2N (n=1,2,3), and (NC8OC8Gn)2N (n=1,2,3) show wider range of LC phases than those of (C6Gn)2N (n=1,2,3), (C8Gn)2N (n=1,2,3). On the other hand, cyanuric chloride, 1,3,5-benzenetricarbonyl trichloride, diaminopropane, and diaminobutane were used as cores for prepare dendrimers peripheral dialkyamines; these are CyCl(C8G2)3, CyCl(C8G3)3, TCA(C8G2)3, TCA(C8G3)3, (C8G3)2DAP, (C8G3)2DAB. Different cores lead to different stacking of dendrimers and thus various liquid crystalline phases were observed.