Influence of imidazole functionalization on the properties of small molecule models of the LPMO active site

A series of small molecule Cu(II) complexes based on tridentate N3 ligands relevant to the histidine brace of the active site of lytic polysaccharide monooxygenase were synthesized and characterized by X-ray crystallography and spectroscopic studies. In order to better understand the role of different structural features and to help bridge the differences between previously reported models, the methylation patterns, imidazole connectivity, linker nature, and type of heterocycle were systematically varied across the series. These modifications lead to important differences in the electrochemical properties of the complexes and their reactivity towards the oxidation of a model substrate.