Iron(III) Complexes of Metal‐Binding Copolymers as Proficient Catalysts for Acid Hydrolysis of Phosphodiesters and Oxidative DNA Cleavage – Insight into the Rational Design of Functional Metallopolymers

Fe3+ complexes of pyridine-containing copolymers were found to be efficient and selective catalysts toward phosphodiester hydrolysis and show significant activity toward oxidative DNA cleavage. The catalysis toward bis(p-nitrophenyl)phosphate (BNPP) hydrolysis exhibits enzyme-like pre-equilibrium kinetics with maximum activities in the range of ca. pH 6–8 and a first-order catalytic proficiency (kcat/ko) of 4.2 × 107-fold at the acidic pH value of 5.3 (i.e., pKa of the coordinated nucleophilic water) and 25 °C, entitling this Fe3+ copolymer an acid phosphodiester catalyst. This catalyst also shows significant selectivity toward BNPP hydrolysis relative to the hydrolyses of p-nitrophenyl phenylphosphonate and p-nitrophenylphosphate monoester, with a ratio of 4250:16:1 in terms of their first-order catalytic proficiencies at pH 8.0 and 25 °C. Fe3+ complexes of a few pyridine-containing copolymers show different hydrolytic activities, which points a direction for rational design of catalytic metallopolymers. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)