Comparative studies on hydrolysis of bis( p-nitrophenyl) phosphate catalyzed by short- and long-alkyl-multiamine metallomicelles

Abstract

Four short- and long-alkyl-multiamine ligands L 1–L 4 have been synthesized and characterized. The catalytic efficiency of complex CuL 1 and functional metallomicelles CuL 2–CuL 4 were comparatively investigated for the hydrolysis of bis( p-nitrophenyl) phosphate (BNPP) in buffered solution at 30 °C. The ternary kinetic model for metallomicellar catalysis was suggested to analyze the experimental data. The kinetic and thermodynamic parameters k ′ N , K T and p K a were obtained. The results indicated that the complexes with 1:1 ratio of ligands L 2–L 4 to copper(II) ion were the kinetic active catalysts, and the deprotonized Cu(II) complex formed by activated water molecule was the real active species for BNPP catalytic hydrolysis. The real rate constant of the reaction catalyzed by CuL 1–CuL 4 was 4.00 × 10 −6, 7.44 × 10 −5, 1.42 × 10 −4 and 4.10 × 10 −4 s −1, respectively. The effects of ligand and microenvironment on the hydrolytic reaction of BNPP have been discussed in detail.