Die selektive Funktionalisierung starker C-H-Bindungen sowie die Oxidation von Wasser durch preiswerte und ungiftige Metalle sind einige der Schlüsselziele der heutigen chemischen Forschung. Es wurde vorgeschlagen, dass hochvalente Eisen-, Mangan- und Kupferkerne als reaktive Intermediate an diesen wichtigen Oxidationsreaktionen, die von biologischen Systemen ausgeführt werden, beteiligt sind, was sie zu begehrten Zielobjekten für biomimetische Synthesestudien macht. Die Herstellung und Charakterisierung von Modell-Oxidometallkomplexen von Eisen, Mangan und Kupfer, zusammen mit detaillierten Reaktivitätsstudien, kann dazu beitragen, die Rolle der sterischen und elektronischen Eigenschaften der Metallzentren zur Regulierung der Reaktivität entsprechender Metalloenzyme zu verstehen. Dieser Aufsatz bietet einen fokussierten Rückblick auf die jüngsten Fortschritte in der biomimetischen Komplexchemie hochvalenter Oxidometallkerne der letzten fünf bis zehn Jahre, die mit unserem Verständnis von biologischen Systemen in Beziehung gebracht werden können.

The selective functionalization of strong C−H bonds and the oxidation of water by cheap and nontoxic metals are some of the key targets of chemical research today. It has been proposed that high-valent iron-, manganese-, and copper-oxo cores are involved as reactive intermediates in important oxidation reactions performed by biological systems, thus making them attractive targets for biomimetic synthetic studies. The generation and characterization of metal–oxo model complexes of iron, manganese, and copper together with detailed reactivity studies can help in understanding how the steric and electronic properties of the metal centers modulate the reactivity of the metalloenzymes. This Review provides a focused overview of the advances in the chemistry of biomimetic high-valent metal–oxo complexes from the last 5–10 years that can be related to our understanding of biological systems.

High-valent cobalt-oxo intermediates are proposed as reactive intermediates in a number of cobalt-complex-mediated oxidation reactions. Herein we report the spectroscopic capture of low-spin (S=1/2) Co^IV-oxo species in the presence of redox-inactive metal ions, such as Sc³⁺, Ce³⁺, Y³⁺, and Zn²⁺, and the investigation of their reactivity in CH bond activation and sulfoxidation reactions. Theoretical calculations predict that the binding of Lewis acidic metal ions to the cobalt-oxo core increases the electrophilicity of the oxygen atom, resulting in the redox tautomerism of a highly unstable [(TAML)Co^III(O^.)]²⁻ species to a more stable [(TAML)Co^IV(O)(Mⁿ⁺)] core. The present report supports the proposed role of the redox-inactive metal ions in facilitating the formation of high-valent metal–oxo cores as a necessary step for oxygen evolution in chemistry and biology.

High-valent cobalt-oxo intermediates are proposed as reactive intermediates in a number of cobalt-complex-mediated oxidation reactions. Herein we report the spectroscopic capture of low-spin (S=1/2) Co^IV-oxo species in the presence of redox-inactive metal ions, such as Sc³⁺, Ce³⁺, Y³⁺, and Zn²⁺, and the investigation of their reactivity in CH bond activation and sulfoxidation reactions. Theoretical calculations predict that the binding of Lewis acidic metal ions to the cobalt-oxo core increases the electrophilicity of the oxygen atom, resulting in the redox tautomerism of a highly unstable [(TAML)Co^III(O^.)]²⁻ species to a more stable [(TAML)Co^IV(O)(Mⁿ⁺)] core. The present report supports the proposed role of the redox-inactive metal ions in facilitating the formation of high-valent metal–oxo cores as a necessary step for oxygen evolution in chemistry and biology.

This review summarizes the properties of group 9–11 metal–oxo and metal–imido complexes, which have been either isolated or proposed as reactive intermediates in metal-catalyzed organic transformations. We begin with a general description of the bonding of transition-metal–oxo and –imido complexes in various geometries, followed by a discussion of complexes from groups 9–11. The focus of this review is to provide a clear picture of the state of the art as well as insight towards potential future synthetic endeavors.

The site-directed generation of a heterodinuclear Fe^IIICu^II complex by using a new asymmetric dinucleating ligand FloH is reported. The iron(III) ion is introduced first on the preferential metal-binding site of the ligand that leads to the formation of the thermodynamically favored five-membered chelate rings upon metal-binding. Copper(II) is introduced in the next step. The stepwise metalation strategy reported here may be extended to the preparation of other heterometallic complexes with the view of avoiding a statistical distribution. Such complexes can offer novel spectroscopic properties, electronic structures, and reactivities in comparison to their homometallic analogues.