Bis-porphyrin arrays. Part 3.The synthesis of model bis-porphyrin dimers and an electrochemical study
Bis-porphyrin arrays. Part 3.The synthesis of model bis-porphyrin dimers and an electrochemical study
复制标题
双卟啉阵列。
DOI：
10.1039/a910323f
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
P. Burn
中科院分区：
文献类型：
--
作者：
R. Beavington;P. Burn
我们成功地合成了exo和endo二苯基乙炔连接的双卟啉二聚体。我们发现，exo-bis-卟啉二聚体可以很容易地以良好的产率制备，而endo-dimer由于meso取代基的空间限制而难以形成。电化学研究表明，双卟啉二聚体的卟啉中心的还原是由双卟啉部分占主导地位。我们发现，前四个单电子还原的exo和endo双卟啉二聚体发生在类似的电位。最后，在更负的电位下，双卟啉二聚体被进一步还原，这显著地改变了随后的氧化过程。这被认为是由于分子中的构象变化导致了“激发态”中轨道密度的变化。
We have successfully synthesised exo and endo diphenylacetylene linked bis-porphyrin dimers. We found that the exo-bis-porphyrin dimer could be easily prepared in good yield whilst the endo-dimer was harder to form due to the steric constraints of the meso-substituents. Electrochemical studies indicated that the porphyrin centred reductions of the bis-porphyrin dimers were dominated by the bis-porphyrin moieties. We found that the first four one-electron reductions of the exo- and endo-bis-porphyrin dimers occurred at similar potentials. Finally, at more negative potentials the bis-porphyrin dimers were reduced further which significantly changed the subsequent oxidation processes. This is thought to be due to a conformational change in the molecule which causes a change in orbital density in the “excited state”.