Five-coordinate M~Ⅱ-semiquinonate (M = Fe, Mn, Co) complexes: reactivity models of the catechol dioxygenases

摘要

A series of five-coordinate M~Ⅱ-semiquinonate (M = Fe, Mn, Co) complexes were synthesized and characterized, including the first example of a mononuclear Fe~Ⅱ-semiquinonate. Intermediates were observed in the reactions of M~Ⅱ-phenSQ (M = Fe, Co) with O_2. Evidence for the relevance of these intermediates to the intradiol catechol dioxygenases was obtained by characterization of the oxidized semiquinone-derived product, muconic anhydride, resulting from the reaction of [PhTt~(tBu)]Co~Ⅱ(3,5-DBSQ) with O_2.