Biology Department Seminar

The cleavage of the chemical bond between the two oxygen (O) atoms of a dioxygen molecule (O2), referred to as dioxygen activation, represents a ubiquitous and important reaction in life processes. Nature has evolved a host of enzymes to cleave this bond under ambient conditions to unleash the oxidizing power of O2 and carry out a variety of physiologically important cellular functions. These enzymes frequently employ iron (Fe) cofactors in their active sites to activate O2. An iron(III)-hydroperoxo (FeIII–OOH) species has been invoked as an key intermediate in the catalytic cycles of such enzymes, with O–O bond cleavage of this species presumably leading to the formation of high valent iron-oxo states that can oxidize organic compounds and fulfill the desired functions of these O2-activating enzymes. However, observation of the direct conversion from FeIII–OOH to high-valent iron-oxo species via O–O bond cleavage has proven elusive in both enzymatic and biomimetic systems. This is perhaps unsurprising given competing Fe–O bond cleavage pathways and the short-lived nature of FeIII–OOH intermediates in enzymatic cycles. I will describe our recent biomimetic efforts towards generating in high yield an FeIII–OOH intermediate and its clean conversion to an oxoiron(IV) complex by O–O bond cleavage. What is the trick here? Can we take a peek into Nature’s secrets to modulate reactivities in O2-activating enzymes?