4-nitrophenyl acetate hydrolysis catalyzed by Cu(II) and Zn(II) complexes of linear oxa-aza polydentate amino alcoholic phenol ligands

The kinetics of p-nitrophenyl acetate (NA) hydrolysis catalyzed by Cu(II) c omplexes of ligands N,N'-bis-(2-hydroxyethyl)-ethylenediamine (L-1) and N-( 2-hydroxybenzyl)-3-amino-propan-1-ol (HL2) and Zn(II) complexes of ligands N-(2-hydroxyethyl)-N'-(2-hydroxybenzyl)-ethylenediamine (HL3) and 3,6,9-tri aza-1-nonanol (L-4) was determined spectrophotometrically at (25+/-0.1) deg reesC and I = 0.10 mol/L KNO3 in phi>(*) over bar * (CH3CN) = 10% at pH 6.5 -9.0 (50 mmol/L buffers), and the second-rate constants k(c) for the cataly sis of NA eater hydrolysis were obtained. The experimental results indicate that coordinated alkoxides Cu(II). . . -OR and Zn(II). . . -OR yielded at neutral pH are strong nucleophiles, and the complexes have a strong ability to catalyze the hydrolysis of NA ester following the double-catalysis mech anism, with k(c) values of 6.72 x 10(-2), 0.126, 4.55 x 10(-2) and 7.66 x 1 0(-2) mol(-1).L .s(-1).