CATALASE-LIKE ACTIVITY OF A WATER-SOLUBLE COMPLEX OF RU(II)

A Ru(II) complex of an unsymmetrical macrocycle (containing two tertia ry amine nitrogen atoms acting as ligands) exhibits a marked catalytic activity far disproportionation of hydrogen peroxide, with both high rate and turnover number Although the stoichiometry is the same as for catalase, the reaction does not obey the simple kinetic law reported for this enzyme. The proposed reaction scheme includes a first slow st ep leading to a catalytic species which undergoes a catalase-like redo x cycle. This scheme fits the experimental kinetic data measured in la rge concentration ranges of hydrogen peroxide and catalyst. The nature of the active species is discussed. (C) 1997 Elsevier Science, Inc.