Suplamolecules with Fine Controlled Metal Assembly for a New Catalyst based on Multi-electron Transfer

其他树枝状大分子与苯甲亚胺树枝状骨架也观察到了径向逐步络合作用。与所有的树枝状聚合物，四步移动的等吸光点观察到逐步加入氯化亚锡。在具有三苯胺核的DPA G4中，在加入3、6、12和24当量的SnCl_2后发生位移。在具有卟啉核的DPA中，在加入4、8、16和32当量后发生位移。在苯胺封端的DPA G4树枝化基元中，在添加1、2、4和8当量后发生位移。在每个树枝状聚合物中，加入溶液中的SnCl_2的量与1^至4^壳层中的亚胺的数量一致<st><th>。这些结果支持了DPA衍生物的络合过程是从核心亚胺向末端亚胺进行的。外亚胺的释电子作用增强了内亚胺的碱性，壳层间亚胺的不同碱性导致了逐步络合。在DPA-F G2与SnCl_2的络合过程中，0-4和5-6当量SnCl_2的加入使DPA-F G_2的紫外-可见吸收光谱中的等吸光点发生了两次移动。该结果表明，存在于2^壳中的亚胺<nd>首先络合，然后存在于1^壳中<st>的亚胺络合，其碱性被吸电子基团降低。在DPA-F G_3中加入SnCl_2，当加入0-4，5-12和13-14当量时，出现三个等吸光点移动。也就是说，存在于2^壳中的亚胺<nd>首先络合，然后存在于3^壳中的亚胺<rd>络合，最后存在于1^壳中的亚胺<st>络合。

The radial stepwise complexation was also observed for the other dendrimers with phenylazomethine dendron skeletons. With all dendrimers, a four-step shift of the isosbestic point was observed with gradual addition of stannous chloride. In DPA G4 with a triphenylamine core, the shifts occur after the addition of 3, 6, 12, and 24 equivalents of SnCl_2. In DPA with a porphyrine core, the shifts occur after the addition of 4, 8, 16, and 32 equivalents. In the aniline-capped DPA G4 dendron, the shifts occur after the addition of 1, 2, 4, and 8 equivalents. In each dendrimer, the amounts of SnCl_2 added to the solution agree with the number of imines in the 1^<st> to 4^<th> shells. These results support that the complexation in DPA derivatives proceeds from the core imines to the terminal ones. The basicity of the inner imines is enhanced by the electron-releasing effect of the outer imines, and the stepwise complexation is caused by the different basicity of the imines between the shells. This complexation behavior means that the number and the position of the metal ions in the dendrimers are controllable.During the complexation of DPA-F G2 with SnCl_2, two shifts in the isosbestic point appeared on adding 0-4 and 5-6 equivalents of SnCl_2 in the UV-vis spectra. This result shows that the imines present in the 2^<nd> shell were complexed first and then those present in the 1^<st> shell, whose basicity was lowered by the electron-withdrawing group. On adding SnCl_2 to DPA-F G3, three shifts of the isosbestic point appeared upon adding 0-4, 5-12, and 13-14 equivalents of SnCL_2. That is, the imines present in the 2^<nd> shell were complexed first, then those present in the 3^<rd> shell, and finally those present in the 1^<st> shell.