| 酚胺型配体Cu(Ⅱ)配合物催化酯水解动力学研究 |
| INVESTIGATION OF 4-NITROPHENYL ACETATE HYDROLYSIS CATALYZED BY COPPER (Ⅱ) COMPLEXES WITH DIPHENOLPOLYAMINE LIGANDS |
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| 摘要: 在25±0.1℃，I=0.1 mol·dm-3 KNO3条件下，采用pH电位滴定法，测定了新型配体，N，N′-二-(2′-羟基)苄基-乙二胺(BEDA)和N，N′-二-(2′-羟基)苄基-二乙烯基三胺(BDTA)的质子化常数以及它们与Cu(Ⅱ)离子的配位平衡常数，并进一步求得了配合物Cu-BEDA和Cu-BDTA中酚羟基的离解常数pKa值。通过分光光度法，在25±0.1℃，I=0.1 mol·dm-3 KNO3，pH=7～9 (50 mmol·dm-3缓冲溶液)条件下，得到了配体的Cu(Ⅱ)配合物催化对-硝基苯酚乙酸酯(NA)水解的的催化速率常数kNP［(mol·dm-3)-1·s-1］，结果表明这类配合物可以用作金属水解酶的模拟物，由催化机理出发对实验结果进行了解释。 |
| 关键词: 金属水解酶 亲核试剂 速率常数 |
| 基金项目: |
| Abstract: The coordination of Cu(Ⅱ) with ligands N, N′-(2-hydroxylbenzyl)-ethylenediamine (BEDA) and N, N′-(2-hydroxybenzyl)-diethylenetriamine (BDTA) has been investigated by pH titration at 25±0.1℃, and I=0.1 mol·dm-3 (KNO3), from which the deprotonation constanst of the phenols in the ligands coordinated with Cu(Ⅱ) were obtained. Furthermore, 4-nitrophenyl acetate (NA) hydrolysis catalyzed by the Cu(Ⅱ) complexes of these ligands in 10% (V/V) CH3CN, at 25±0.1℃, I=0.1 mol·dm-3 (KNO3) and pH range 7～9(50 mmol·dm-3 buffers), has been carried out and the second-order rate constants (kNP) of the reactions were obtained spectrophotometrically. The experimental results indicate that these Cu(Ⅱ) complexes can be used as models of metallohydrolases with participation of two kinds of nucleophiles, i.e. Cu(Ⅱ)-bound -OAr and Cu(Ⅱ)-bound -OH. |
| Keywords: metallohydrolase nucleophile rate constant |
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| 聂丽,寇福平,解永树,宗汉兴,林瑞森.酚胺型配体Cu(Ⅱ)配合物催化酯水解动力学研究[J].无机化学学报,1999,15(2):165-172. |
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