Zn(II)-Catalyzed Cleavage of 2-Hydroxypropyl p-Nitrophenyl Phosphate in Gemini 16-6-16 Micelles

Hydrolytic cleavage of 2-hydroxypropyl p-nitrophenyl phosphate (HPNP) catalyzed by Zn(II)-biap (biap: N, N- bis (2-ethyl-5-methyl-imidazole-4-ylmethyl) aminopropane) complex was investigated spectrophotometrically in a cationic Gemini surfactant 16-6-16 [Bis(hexadecyldimethylammonium)hexane bromide] micellar solution. Effects of various factors (pH, [complex], temperature [K], amine additives, etc.) on the catalytic cleavage of HPNP were evaluated systematically. Experimental observations showed that higher rate acceleration of HPNP cleavage promoted by Zn(II)-biap complex was obtained in the 16-6-16 micellar solution in comparison with the background value (ko) of HPNP cleavage. Compared with the ZnL+G(16-6-16) system, the results reveal that a 1.22.9 folds rate enhancement was given in the catalytic systems containing diethylenetriamine (DETA). Additionally, the addition of diethylenetriamine (DETA) resulted in a 1.22.7 folds higher rate enhancement in contrast with 1,2-Ethylenediamine (EDA).