Metalloenzyme catalyzed dioxygen activation is a key process for many metabolisms and signal transmissions in bio-systems. Heme enzymes and non-heme enzymes are the two groups with the dioxygen activation functions. Model compounds of these enzymes are introduced into catalyzed reactions to illustrate the mechanisms of dioxygen activation through characterizations of intermediates and final products. Study on reactivity and electronic effects of the model compounds can guide the design of novel catalysts. Besides, some heme enzymes and non-heme enzymes can selectively activate C-H bonds, which is a difficult transformation in chemistry. Thus, these model compounds can be applied as catalysts to overcome some ineradicable difficulties in drug discovery, chemical engineering and energy transformation areas. This review introduces the recent development in mechanism study on dioxygen activation of heme and non-heme enzymes. The design of porphyrinoid and 2-His-1-carboxylate facial triad models, and the electronic structures of high-valent metal-oxo complexes are analyzed. The relationship between reactivity and the electronic effects of ligands in models is summarized. In addition, some existing problems in the area and prospects of enzyme model compounds in research and further applications are also proposed in this review. Contents
1 Introduction
2 Study of models
2.1 Model design
2.2 Mechanism research through models
2.3 Theoretical studies of models
2.4 Reactivity principles of models
3 Application of models
4 Conclusions and outlook