Catalytic oxygenation of various monophenols by copper(I) complexes with bis(pyrazolyl)methane ligands: differences in reactivity

Three new mononuclear copper(I) complexes supported by the symmetric ligands 1,1'-methylenebis-1H-pyrazole (BPM), 1,1'-methylenebis(3-methyl-1H-pyrazole) (mBPM), and 1,1'-methylenebis(3,5-di-methyl-1H-pyrazole) (dmBPM) were synthesized as catalytic model systems of tyrosinase. The influence of various functional groups on the catalytic conversion of monophenols is investigated and the formation of the corresponding ortho-quinones is monitored using UV/vis and NMR spectroscopy. Comparison of various monophenols reveals the differences in reactivity which are analyzed and interpreted based on key intermediates of the mechanistic cycle.