Figure 1.

Proposed TauD mechanism. States of the catalytic cycle that are highlighted in gray have been characterized or mimicked in crystallo.^3,8–10 The structure at the bottom right is presented herein with vanadyl substituted for the functional ferryl complex. We have chosen to depict succinate in a bidentate coordination mode throughout the cycle, on the basis of its observed binding mode in the vanadyl complex. It should be noted, however, that ligation of the coproduct could be dynamic in solution.