Distinguishable effects of varied micelles on the hydrolysis of PNPP by dinuclear copper(II) complexes containing oxo-bridged unit

作者：Jiang Weidong; Xu Bin; Liu Fuan; Xiang Zhen

来源：Colloid and Polymer Science, 2015, 293(9): 2663-2670.

DOI：10.1007/s00396-015-3654-0

• Esterolysis
• Micelles
• Solubilization
• Bimetallic activation
• Steric geometry

Two alkoxo/hydroxide-bridged dinuclear copper(II) complexes (Cu(2)L1 and Cu(2)L2) were prepared for evaluating their activity towards the hydrolysis of p-nitrophenyl picolinate (PNPP). Importantly, this work investigated the effects of varied micelles of four surfactants, e.g., cationic gemini 16-2-16 and 16-6-16, single-chain CTAB (hexadecyltrimethylammonium bromide), and LSS (n-lauroylsarcosine sodium), on the PNPP hydrolysis by the as-prepared copper(II) complexes. The experimental results indicate that at neutral pH both of complexes exhibited much better activity by excess four-order of magnitude rate enhancement. For instant, rate constants of PNPP hydrolysis by Cu(2)L1 and bromo-containing Cu(2)L2 are approximate 49,569.6- and 31,123.5-fold than that of PNPP spontaneous hydrolysis. In addition, the hydrolytic reactivity of the bromo-containing Cu(2)L2 is subordinate to that one without bromine, Cu(2)L1. Moreover, it is found that the micellar solution of gemini 16-6-16 is proved to be the best medium, and whereas LSS micellar solution is the worst one. Particularly, the pK (a) values of the Cu(II)-bound H2O are determined by a new methodology which is correlative to second derivatives.

• 出版日期2015-9
• 单位四川轻化工大学