Institute of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489, Berlin, Germany.
Chemistry. 2021 Feb 24;27(12):3991-3996. doi: 10.1002/chem.202004945. Epub 2021 Feb 2.
The synthesis and characterization of a hetero-dinuclear compound is presented, in which a copper(I) trishistidine type coordination unit is positioned directly above a zinc porphyrin unit. The close distance between the two coordination fragments is secured by a rigid xanthene backbone, and a unique (intramolecular) copper porphyrin-π-bond was determined for the first time in the molecular structure. This structural motif was further analyzed by temperature-dependent NMR studies: In solution at room temperature the coordinative bond fluctuates, while it can be frozen at low temperatures. Preliminary reactivity studies revealed a reduced reactivity of the copper(I) moiety towards dioxygen. The results adumbrate why nature is avoiding metal porphyrin-π-bonds by fixing reactive metal centers in a predetermined distance to each other within multimetallic enzymatic reaction centers.
呈现了一种杂双核化合物的合成与表征，其中一个铜（I）三组氨酸型配位单元直接位于锌卟啉单元的正上方。两个配位片段之间的近距离通过刚性呫吨骨架来保证，并首次在分子结构中确定了独特的（分子内）铜卟啉-π 键。通过温度依赖性 NMR 研究进一步分析了这种结构基序：在室温下的溶液中，配位键发生波动，而在低温下可以冻结。初步的反应性研究表明，铜（I）部分对氧气的反应性降低。这些结果预示了为什么自然界通过将活性金属中心固定在多金属酶反应中心内彼此预定的距离来避免金属卟啉-π 键。
