MACROCYCLIC METAL-COMPLEXES BUILT ON POLYETHYLENIMINE

Metal centers with macrocyclic ligands are created on polyethylenimine (PEI) by the condensation of dicarbonyl compounds with PEI in the presence of transition-metal ions. The macrocycle-containing PEIs possess fixed multivalent cationic centers and exhibit much greater affinity for benzoate anions compared with the unmodified PEI. Complex formation with anionic ester 2-nitro-4-carboxyphenyl acetate was reflected in the saturation kinetic behavior observed for the deacylation of the ester promoted by the macrocycle-containing PEIs. On the basis of the kinetic data, it is proposed that the anionic substrate is anchored by the metal center upon complexation with the macrocycle-containing PEI derivative and that the amine nitrogen atom located close to the metal center attacks the acyl carbon on the bound ester.