Electrochemistry of fullerene/transition metal complexes: Three decades of progress
Electrochemistry of fullerene/transition metal complexes: Three decades of progress
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DOI：
10.1016/j.ccr.2020.213623
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发表时间：
2020-11
影响因子：
20.6
通讯作者：
A. Balch;K. Winkler
中科院分区：
文献类型：
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作者：
A. Balch;K. Winkler
本综述的重点是过渡金属富勒烯配合物的电化学性质。在综述的第一部分中，简要概述了富勒烯的配位特性。还简要描述了通过连接体共价连接到富勒烯笼的金属配合物（过渡金属、茂金属、金属卟啉的多吡啶基配合物）。过渡金属的η2-C60配合物表现出与富勒烯笼还原和金属中心氧化相关的电化学活性。过渡金属的 η2-C60 配合物在还原和氧化时通常不稳定，金属-富勒烯键断裂。据报道，过渡金属簇的 η2-C60 配合物具有更稳定的电化学行为。通过金属簇结合成二聚体的富勒烯部分可以在它们之间进行电子通信。 η2-C60配位还负责形成电化学活性富勒烯配位聚合物。这些大分子系统在负电势下表现出电化学活性和n掺杂特性。与 η2-C60 配合物相比，聚合物中的金属-富勒烯键在电还原条件下更加稳定。具有半夹心或夹心结构的η5-C60配合物在与二茂铁笼还原相关的负电势范围内以及由于金属中心氧化而在正电势范围内也表现出电化学活性。与 η2-富勒烯配合物相比，过渡金属的 η5-富勒烯配合物在电化学条件下更加稳定。过渡金属络合物的电化学性质对于理解这些系统的光化学性能非常重要，其中金属中心与共价连接到富勒烯部分的螯合配体配位。这些配合物的电化学行为通常是所形成的二元组和三元组的电化学性质的组合。基态氧化还原位点之间的电子通讯取决于复杂的几何形状、电化学活性中心之间的距离以及连接体的性质。
This review is focused on the electrochemical properties of fullerene complexes of transition metals. In the first part of the review, the coordination properties of fullerenes are briefly overviewed. Metal complexes (polypyridyl complexes of transition metals, metallocenes, metalloporphyrins) that are covalently attached to the fullerene cage through the linkers are also briefly described. The η2-C60complexes of transition metals exhibit electrochemical activity related to the fullerene cage reduction and metal center oxidation. Upon reduction and oxidation, η2-C60complexes of transition metals are usually unstable and the metal-fullerene bond is cleaved. More stable electrochemical behavior was reported for η2-C60complexes of transition metal clusters. Fullerene moieties bonded into dimers through metal clusters can communicate electronically between themselves. The η2-C60coordination is also responsible for the formation of electrochemically active fullerene coordination polymers. These macromolecular systems show electrochemical activity at negative potentials and a n-doped properties. The metal-fullerene bond in polymers is much more stable under electroreduction conditions in comparison to the η2-C60complexes. The η5-C60complexes with a half-sandwich or sandwich structure also exhibit electrochemical activity in negative potential range related to the ferrocene cage reduction and in positive potentials due to the metal center oxidation. In contrast to η2-fullerene complexes, the η5-fullerene complexes of transition metals are much more robust under electrochemical conditions. The electrochemical properties of transition metal complexes in which the metal center is coordinated to the chelating ligand covalently linked to the fullerene moiety are important for understanding the photochemical performance of these systems. The electrochemical behavior of these complexes are usually combination of electrochemical properties of formed dyads and triads. The electronic communication between redox sites in the ground state depends on the complex geometry, distance between electrochemically active centers, and the nature of the linker.