Metallomicellar Catalysis: Catalytic Cleavage of p-Nitrophenyl Picolinate by Cu~(2+) Complex of 4-Chloride-2,6-bis(N-hydroxyethylaminomethyl)-benzophenol in Micellar Solution

摘要

The hydrolysis of p-nitrophenyl picolinate (PNPP) catlayzed by the Cu(II) complex of 4-chloride-2,6-bis(N-hydroxyethylaminomethyl)-benzophenol was investigated kinetically by observing the rates of release of p-nitrophenol in the presence of three surfactants, which are hexadecyltrimethylammonium bromide, n-lauroylsarcosine sodium, and polyoxyethylene(23) lauryl ether, at different pH and 25deg C. The scheme for the reaction involving a ternary complex comprising ligand, metal ion, and substrate in a micelle wa established, and the relatie kinetic and thermodynamic parameters wee determined, including first-order rate constant (k_N), association constant (K_s) for ternary complex, and pK_a for the hydroxide ion of the ternary complex. The reaction mechanism was discussed.