Acid-base and spectroelectrochemical properties of doubly N-confused porphyrins
Acid-base and spectroelectrochemical properties of doubly N-confused porphyrins
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DOI：
10.1021/ic000441j
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发表时间：
2001-04-23
影响因子：
4.6
通讯作者：
Furuta, H
中科院分区：
文献类型：
--
作者：
Araki, K;Winnischofer, H;Furuta, H
顺式-双N-混杂的卟啉。H_2N_2CP。从二氯甲烷中的酸碱和电化学行为的角度研究了含有两个相邻的混杂吡咯环的化合物。这种新型的卟啉异构体可以在中心核心形成两个金属-碳键，在异常高的氧化态下稳定金属离子。此外，两个外部的N-吡咯原子仍然可用于酸碱和特定溶剂的相互作用。吡咯N原子的质子化按两个连续的步骤进行，而在碱的存在下只观察到一个去质子化步骤。同样，对于银和铜的络合物，检测到了外部吡咯环的质子化和去质子化，证实了金属化物种的结构为M-III-HN2CP。结合酸碱平衡研究，在-0.9V和1.4V下分别检测到金属离子的电化学还原(III/II氧化还原过程)和大环环的氧化。在-0.5V和1.3V附近观察到的附加波被分配给涉及与双N-混淆的卟啉相关的水分子的氧化还原过程。
The cis-doubly N-confused porphyrin. H2N2CP. containing two adjacent confused pyrrole rings has been investigated from the Feint of view of its; acid-base and electrochemical behavior in dichloromethane. This novel porphyrin isomer can form two metal-carbon bonds in the, central core, stabilizing metal ions in unusually high oxidation states. Furthermore, the two outside N-pyrole atoms remain available for acid-base and specific solvent interactions Protonation of the pyrrole N atoms proceeds according to two successive steps, while only a single deprotonation step has been observed in the presence of bases. Similarly, in the case of the silver and copper complexes the protonation and deprotonation of the outer pyrrole rings have been detected, confirming the structure of the metalated species as M-III-HN2CP. The electrochemical reduction of the metal ions (III/II redox process) and oxidation of the macrocycle ring have been detected respectively at -0.9 and 1.4 V based on spectroelectrochemical measurements in conjunction with the acid/base equilibrium studies. Additional waves observed around -0.5 and 1.3 V have been assigned to redox processes involving water molecules associated with the doubly N-confused porphyrins.