Synthesis, structure, and catecholase reaction of a vanadate ester system incorporating monoionized catechol chelation

An example of the title system is VO(Hdbcat)(A(1)), 1a, where the tridentat e coligand (A(1))(2-) is a diionized salicylhydrazone. The reaction of la w ith O-2 in solution forms the basis of the depicted cycle where 1a is the r eactive intermediate and V2O3(A(1))(2), 3a is the catalyst. The net result is the catecholase reaction H(2)dbcat +1/2 O-2 --> dbq + H2O. The phenolic proton of la is proposed to have a crucial role in anchoring OL thus making it O-2-sensitive.