First synthesis of phenylazomethine dendrimer ligands and structural studies.
First synthesis of phenylazomethine dendrimer ligands and structural studies.
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首次合成苯偶氮甲碱树枝状聚合物配体并进行结构研究。
DOI：
10.1021/ja004239r
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发表时间：
2001
影响因子：
15
通讯作者：
K. Yamamoto
中科院分区：
文献类型：
--
作者：
M. Higuchi;S. Shiki;K. Ariga;K. Yamamoto
以四氯化钛为催化剂，芳香酮和芳香胺为原料，采用收敛法合成了具有π共轭主链的新型树枝状聚苯甲亚胺（DPAs）.所获得的树枝状聚合物DPA G1-4（命名为GX，其中X是代数）显示出高的热稳定性（在DPA G4中Td（10%）521 ℃）和对常用溶剂如氯仿、THF和DMSO的高溶解度，这与具有非常低溶解度的常规线性聚苯甲亚胺不同。通过GPC测定和基于DPA G2的结晶结构的分子模型，确认DPA G4分子具有球状结构。DPA G2的晶体数据：单斜空间群P2（1）/a，a = 25.352（4）A，B = 8.577（2）A，c = 16.151（2）A，β = 106.25（1）度，V = 3371.6（10）A（3），Z = 2，D（calc）= 1.168 g/cm（3），μ（Cu Ka）= 0.536 cm（-1），最终R = 0.089，R（w）= 0.287。分子模拟表明，DPA G4分子具有球形结构，其中高度、宽度和深度分别为2.3、2.9和2.5 nm。TEM和AFM照片显示DPA G4分子具有球形结构（直径：2.3nm），并且通过浇铸规则地组装在板上。通过pi-A测量估计，在水上单层中一个DPA G4分子的占据面积为3.8-4.2 nm（2）（计算直径为2.2-2.3 nm，与TEM结果一致）。NMR研究（130 ℃下的1H NMR和T（1）测量）支持DPA G4在溶液中的构象刚性。
Novel dendritic polyphenylazomethines (DPAs), which consist of a pi-conjugated backbone, were synthesized up to the fourth generation by the convergent method via dehydration of aromatic ketones with aromatic amines in the presence of titanium(IV) tetrachloride. The obtained dendrimers, DPA G1-4 (designated as GX, where X is the generation number), show high thermostability (Td(10%) 521 degrees C in DPA G4) and high solubility for the common solvents such as chloroform, THF, and DMSO unlike the conventional linear polyphenylazomethines, which have very low solubilities. The DPA G4 molecule was confirmed to have a spherelike structure by GPC measurement and a molecular model based on the crystal structure of DPA G2. Crystal data for DPA G2: monoclinic space group P2(1)/a, a = 25.352(4) A, b = 8.577(2) A, c = 16.151(2) A, beta = 106.25(1) degrees, V = 3371.6(10) A(3), Z = 2, D(calc) = 1.168 g/cm(3), mu(Cu Kalpha) = 0.536 cm(-1), final R = 0.089, and R(w) = 0.287. The molecular modeling reveals that a DPA G4 molecule has a spherelike structure, in which the height, width, and depth are 2.3, 2.9, and 2.5 nm, respectively. The TEM and AFM pictures show the DPA G4 molecules to have a spherelike structure (the diameter: 2.3 nm) and are regularly assembled on a plate by casting. The occupied area of one DPA G4 molecule in a monolayer on water was estimated by pi-A measurements to be 3.8-4.2 nm(2) (the calculated diameter 2.2-2.3 nm, which agreed with the TEM result). NMR studies (1H NMR at 130 degrees C and T(1) measurements) supported a conformational rigidity of DPA G4 in solution.