Leventis Nicholas, Yang Jinhua, Fabrizio Eve F, Rawashdeh Abdel-Monem M, Oh Woon Su, Sotiriou-Leventis Chariklia
NASA Glenn Research Center, 21000 Brookpark Road M.S. 49-1, Cleveland, Ohio, USA.
J Am Chem Soc. 2004 Apr 7;126(13):4094-5. doi: 10.1021/ja0390247.
We report the redox properties of four star systems incorporating the 4-benzoyl-N-alkylpyridinium cation; the redox potential varies along the branches but remains constant at fixed radii. Bulk electrolysis shows that at a semi-infinite time scale all redox centers are electrochemically accessible. However, voltammetric analysis (cyclic voltammetry and differential pulse voltammetry) shows that only two of the three redox-active centers in the perimeter are electrochemically accessible during potential sweeps as slow as 20 mV s-1 and as fast as 10 V s-1. On the contrary, both redox centers along branches are accessible electrochemically within the same time frame. These results are explained in terms of slow through-space charge transfer and the globular 3-D folding of the molecules and are discussed in terms of their implications on the design of efficient redox functional dendrimers.
我们报告了包含4-苯甲酰基-N-烷基吡啶鎓阳离子的四个星型体系的氧化还原性质；氧化还原电位沿分支变化，但在固定半径处保持恒定。本体电解表明，在半无限时间尺度下，所有氧化还原中心在电化学上都是可及的。然而，伏安分析（循环伏安法和差分脉冲伏安法）表明，在电位扫描速度低至20 mV s-1和高达10 V s-1时，周长上三个氧化还原活性中心中只有两个在电化学上是可及的。相反，沿分支的两个氧化还原中心在同一时间范围内在电化学上是可及的。这些结果用缓慢的空间电荷转移和分子的球状三维折叠来解释，并就其对高效氧化还原功能树枝状大分子设计的影响进行了讨论。
