高等学校化学学报 ›› 1997, Vol. 18 ›› Issue (4): 513.

• 论文 • 上一篇    下一篇

带有苯酚侧臂的四氮大环Zn(Ⅱ)配合物催化羧酸酯水解研究

林华宽, 寇福平, 朱守荣, 陈荣悌   

  1. 南开大学化学系, 天津, 300071
  • 收稿日期:1996-03-19 出版日期:1997-05-24 发布日期:1997-05-24
  • 通讯作者: 林华宽、男, 52岁, 博士, 教授.
  • 作者简介:林华宽、男, 52岁, 博士, 教授.
  • 基金资助:

    国家自然科学基金

Carboxyester Hydrolysis Promoted by New Zinc(Ⅱ) Macrocyclic Tetraamine Complexes with a Phenol Pendant

LIN Hua-Kuan, KOU Fu-Ping, ZHU Shou-Rong, CHEN Rong-Ti   

  1. Department of Chemistry, Nankai University, Tianjin, 300071
  • Received:1996-03-19 Online:1997-05-24 Published:1997-05-24

摘要: 合成并表征了在大环侧臂引入取代苯酚作为功能基团的新型四氮大环配体(L1,L2和L3).对配体L3的质子化过程及其与Zn(Ⅱ)的配位过程的研究表明,配体中的酚羟基与四氮大环环中的质子之间存在较强的氢键.测得配体及配合物中酚羟基的pKa分别为8.3和8.5.考察了上述3个配体的Zn(Ⅱ)配合物作为水解锌酶的模拟物催化对硝基苯酚乙酸酯(NA)水解的动力学行为,测得它们催化NA水解的二级反应速率常数kc/[(mol/L-1·s-1]分别为3.48×10-2、1.52×10-2和2.85×10-2.

关键词: 功能性四氮大环, 水解酶, 催化, 速率常数

Abstract: Three new macrocyclic tetraamine ligands(L1,L2,L3) bearing substituted phenolpendant were synthesized and charaterized by elementary analysis, IR, and 1H NMR.By pHtitration at 25±0.1℃, I=0.1 mol/L KNO3, studies of protonation of L3 and complexationof Zn(Ⅱ) with L3 have been carried out and revealed that the pendant phenol deprotonateswith relative low PKa values of 8.3 and 8.5 for these two cases, respectively.It is due to theformation of hydrogen bond between phenol and proton combining on the nitrogen atoms ofmacrocycle, and the coordination between phenol and Zn(Ⅱ) metal ion.The Zn(Ⅱ)-boundphenol is shown to be a reactive nucleophile and catalyzes 4-nitrophenyl acetate(NA) hydrol-ysis.Akinetic study of NAhydrolysis by these three ligands'Zn (Ⅱ) complexes in 10%(volume ratio) CH3CNat 25℃, I =0.1 mol/L NaClO4, and pH 8.63 (20mmol/L Trisbuffer), has established a second-order rate constant kc/L (mol/L)-1· s-1 ]of 3.48×10-2,1.52×10-2, 2.85×10-2, respectively.

Key words: Functionalized macrocycle, Hydrolytic enzyme, Catalysis, Rate constant

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