Synthesis of Bio-inspired μ-oxo Heterobimetallic Nonheme Complexes

Abstract

Enzymes with dinuclear metallocofactors perform versatile functions in nature. In their catalytic cycles, the two metal ions are often connected through a bridging ligand with resulting cooperative effects. Oxo-bridged heterobimetallic species stand out and act as crucial intermediates in various bimetallic active sites. For decades different approaches have been investigated to prepare synthetic μ-oxo heterobimetallic molecules. However, the synthetic strategies either have difficulties in selectively binding the two metals at specific sites while avoiding mixtures and homodinuclear side products, or require complicated unsymmetrical ligand synthesis. This thesis explores a way of quantitatively obtaining μ-oxo heterobimetallic nonheme complexes from the inner sphere electron transfer reaction between ¬nonheme oxoiron(IV) species and a reducing metal salt. Specifically, two types of molecules with Fe–O–Cr and Fe–O–Mn cores are prepared, and based on thorough spectroscopic characterization their structures have been identified. The effect of the Fe coordination ligand to the Fe–O–Cr core is discussed in detail. The Fe–O–Mn species are among the very few synthetic complexes with Fe/Mn bimetallic center, and their structures and reactivities have been compared with the Fe/Mn intermediates in Class Ic RNR. This research has given rise to an alternative way of synthesizing μ-oxo heterobimetallic nonheme complexes with convenience and high efficiency.