Preparation of dendrimers with cooperated functional groups.

1.合成了含和不含蒽醌端基(AQ)的雪花状卟啉树枝状大分子。在树枝状大分子中观察到了从支链或共轭链到锌卟啉核心的高效分子内单重态能量转移。当含有AQ的树状分子中的锌卟啉核心在脱气THF中被激发时，锌卟啉的荧光强度比没有AQ的树状分子降低了31%。荧光猝灭程度在极性溶剂中更为显著。这些结果表明，带有AQ的树状大分子的荧光猝灭是由于分子内电子从锌卟啉核心转移到AQ所致。与参比化合物的相对荧光强度比较表明，树枝状结构对电子传递速率有明显的增强作用。合成了既含有柔性侧链又含有刚性共轭链的新型树枝状聚合物。在刚性共轭链和柔性支链的末端引入联吡啶单元，通过金属络合作用控制支链的构象。在室温下，树枝状分子在氯仿-甲醇(1：1)中形成1：1铁(II)络合物。制备了五个雪花状树枝状大分子的共价连接组装。具有一个碘末端和三个苯基末端(AB3型)、在共轭链末端具有四个乙炔基末端(A4型)的雪花状树枝状大分子是五聚体的关键构筑基团。A3B型树状大分子与A4树状大分子的Sonogashira偶联反应以19%的产率得到了所需的五聚体。通过核磁共振和MALDI-TOF质谱学对五聚体进行了明确的表征。UV-Vis和荧光光谱表明，分子内的单线态能量从四个外围的锌卟啉单元转移到游离碱基的卟啉核心。

1. Snowflake-shaped porphyrin dendrimers with and without anthraquinonyl terminals (AQ) were prepared. Highly efficient intramolecular singlet energy-transfer from the branching chains or conjugated chains to the Zn porphyrin core was observed in dendrimers. When the Zn porphyrin core in the dendrimer with AQ was excited in degassed THF, the intensity of the Zn porphyrin florescence decreased to 31% compared to dendrimer without AQ. The degree of fluorescence quenching is more remarkable in polar solvent. These results suggest that the fluorescence quenching in the dendrimer with AQ is attributable to the intramolecular electron-transfer from the Zn porphyrin core to AQ. Comparison of the relative fluorescence intensity with reference compound suggested that the remarkable enhancement of the electron-transfer rate by dendritic architectures.2. Novel dendrons containing both flexible side chains and a rigid conjugated chain were prepared. Bipyridine units were incorporated at the end of the rigid conjugated chain as well as the flexible branched chains to control the conformation of the branching chains by a metal complexation. The dendron formed 1:1 iron(II) complexes in chloroform-methanol (1:1) at room temperature.3. A covalently linked assembly of the five snowflake-shaped dendrimers was prepared. The snowflake-shaped dendrimers with an iodo and three phenyl terminals (AB3-type) and with four ethynyl terminals at the end of conjugated chains (A4-type) served as key building brocks for the pentamer. Sonogashira coupling reaction of the A3B-type dendrimer with the A4 dendrimer afforded the desired pentamer in 19% yield. The pentamer was unambiguously characterized by means of NMR and MALDI-TOF mass spectroscopy. UV-Vis and fluorescence spectroscopy suggested intramolecular singlet energy transfer from the four peripheral zinc porphyrin units to the free base porphyrin core.