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) complexes of ligands N,N prime -bis-(2-hydroxyethyl)-ethylenediamine(L1) and N-(2-hydroxybenzyl)-3-amino-propan-1-ol(HL2) and Zn(II) complexes of ligands N-(2-hydroxyethyl)-N prime -(2-hydroxybenzyl)-ethylenediamine(HL3) and 3,6,9-triaza-1-nonanol(L4) was determined spectrophotometrically at (25 ± 0. 1)°C and I = 0. 10 mol/L KNO3 in φ(CH3CN) = 10% at pH 6. 5-9. 0(50 mmol/L buffers), and the second-rate constants kc for the catalysis of NA ester hydrolysis were obtained. The experimental results indicate that coordinated alkoxides Cu (II) [midline ellipsis] -OR and Zn (II) [midline ellipsis] -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 mechanism, with kc values of 6. 72×10-2, 0.126, 4. 55×10-2 and 7. 66×10-2 mol-1 [Closed Circle] L [Closed Circle] s-1.