Modelling Binuclear Metallobiosites: Insights from Pyrazole-Supported Biomimetic and Bioinspired Complexes

Numerous enzymes use two closely spaced metal ions to activate and transform small molecules. This allows these biocatalysts to perform diverse physiological functions, achieving impressive chemistry under remarkably mild conditions. Model studies of these metalloenzymes contribute to furthering our understanding of the unusual mechanistic aspects and interplay of cooperative effects used by Nature, and help provide clues as to how such reactivity might be harnessed for applications outside of the natural systems. This micro-review describes synthetic models of binuclear metalloenzymes, focusing on complexes which are bridged by pyrazole ligand scaffolds. Structural and functional models of iron, nickel, copper and zinc binuclear active sites are discussed, in addition to several cobalt complexes possessing biologically relevant features. Metal separation and secondary-coordination-sphere interactions are recurring themes which aid in highlighting aspects of common importance in the native enzymes.