[Zn(dien)_2]Cl_2·H_2O的合成、晶体结构及其催化p-硝基苯酚醋酸酯的水解动力学研究  

Synthesis,Crystal Structure of [Zn(dien)_2]Cl_2·H_2O and Catal ysis Hydrolysis of p-Nitrophenyl Acetate by its Zn(Ⅱ) Complexes

作　　者：陈华梅[1] 岳凡[1] 封顺[1] 王吉德[1] 杨红伟[1] 刘爱华[1] 郁开北[2] 

机构地区：[1]新疆大学化学化工学院,乌鲁木齐830046 [2]中国科学院成都分院分析测试中心,成都610041

出　　处：《化学通报》2005年第3期214-219,共6页Chemistry

摘　　要：在乙醇中合成了 [Zn(dien) 2 ]Cl2 ·H2 O并得到其晶体结构 ,该配合物属单斜晶系 ,P2 1 c空间群 ,a =1 3 479(2 )nm ,b =0 883 2 (1 )nm ,c=1 3 95 2 (2 )nm ;β=1 0 1 93°,V =1 62 5 1 (4 )nm3 ,Z =4;μ =1 840mm-1,DC=1 474g·cm-3 ,F(0 0 0 ) =760 ,R1=0 0 3 3 9,wR2 =0 0 5 6。用pH电位法得到了二乙三胺(dien)的质子化常数及其与锌 (Ⅱ )配合物的稳定常数。在pH7 7～ 1 0 2范围内 ,用分光光度法测定了配合物催化p_硝基苯酚醋酸酯 (NA)的水解动力学。结果表明 ,催化水解速率对底物 (NA)及配合物的浓度均呈假一级反应 ,水解反应遵循速率方程dC dt=(kobs CZn+kOH[OH-]+k0 )CNA ,催化反应受酸碱平衡控制 ,Zn(dien) (OH) + 与Zn(dien) 2 (OH) + 是催化型体。The complex [Zn(dien) 2]Cl 2·H 2O (dien=diethylenetriamine) h a ve been synthesised by the reaction of ZnCl 2 and diethylenetriamine in et hanol and its c rystal structure was determined by Siemens P4 X_ray diffraction. The results sho w that the complex is monoclinic,space group P2\-1/c,the cell parameters a re: a=1.3479(2)nm, b=0.8832(1)nm, c=1.3952(2)nm; β=101.93 °, V=1.6251(4)nm 3, Z=4; μ=1.840mm -1,D C =1.474g·cm -3 , F(000)=760, R 1 =0.0339, wR 2 =0.056. The protonation constants of dien and the stabilty constants of its Zn(Ⅱ) complexes have been determined b y pH potentiometric method. The kinetics of promoted hydrolysis of p _nitrophenyl acetate (NA) was studied by spectrophotometry. Both hydroxo species Zn(dien)(OH) + and Zn(dien) 2(OH) + promote NA hydrolysis at room temperature. The catalytic rate of Zn(dien)(OH) + follow the law o f dC/dt=(k obs C Zn + k OH [OH -] + k 0)C NA.The two species: Zn(dien)(OH) + and Zn(dien) 2 (OH) + play cru cial roles in hydrolytic reaction of NA. In the process of Zn(dien)(OH) + hydrolyzing NA, the nucleophile reagent Zn—OH - is the active center. Ac c ording to the crystal structure of [Zn(dien) 2]Cl 2·H 2O, the w ater molecular is bonded on the primary amine of one dien of Zn(dien) 2 ins tead of on Zn(Ⅱ), so it can be deduced that the hydroxyl on Zn(dien) 2(O H) + is originated from the water bonding on the diethylenetriamine.

关 键 词：配合物 水解动力学 PH电位法 晶体结构 单斜晶系 催化 锌(Ⅱ) 醋酸酯 硝基苯酚 合成 

分 类 号：O625[理学—有机化学] O643.3[理学—化学]