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酸性媒介黄GG与[Coen2(OH)(OH2)]2+的取代反应动力学及反应机理
Kinetics of the substitution reaction of Co(III)bis(ethylenediamine) complexes withsolochrome yellow GG
【摘要】 用分光光度法研究cis-[Coen2(OH)(OH)2](ClO4)2(en为乙二胺)与酸性媒介黄GG染料(2-羟基-5-[(4-苯磺酸基)偶氮基]苯甲酸)的取代反应动力学.用pH电位滴定法测定了[Coen2(OH)2]+、[Coen2(OH)(OH2)]2+60℃时的加质子反应平衡常数.用分光光度法测得60℃时染料的酸解离常数.60℃离子强度为0.1mol/kgNaClO4时,各络合质点与染料的反应活性顺序为[Coen2(OH)(OH2)]2+>[Coen2(OH)2]+>[Coen2(OH2)2]3+.由表观速率常数kobs与Co(Ⅲ)络合物浓度的关系及反应活化参数西ΔH、ΔS可见,该取代反应是按SN2缔合机理进行的.
【Abstract】 The kinetics of the substitution reaction of complex species [ Co en2(OH2)]23+,[ Coen2(OH)(OH2)]2+,[Coen2(OH)2]+ with 5-(4-sulfo phenylazo) salicylic acid has been studied spectrophotometrically.The protonation constants of [Coen2(OH)(OH2)]2+ Co[en2(OH)(OH2)]2+,and the acid dissociation constant of the phenolic group of azo dye were determined with PH potentiometric titration and spectrophotometrically respectively at 60℃.The sequence of the reactivity of reaction at 60℃ with 0.1 mol/kg NaClO4 present is: [Coen2(OH)(OH2)]2+>[Coen2(OH)2]+>[Coen2 (OH)2]3+.The relationship of the kobs, with the concentration of Co(III) complex and the activation parameters ΔH,ΔS support the reaction ispassed through a SN2 associative route.
【Key words】 cobalt complexes; diethylamine(p); substitution reactions,reaction kinetics,reaction mechanism, solochrome yellow GG;
- 【文献出处】 复旦学报(自然科学版) , 编辑部邮箱 ,1994年01期
- 【分类号】O313
- 【被引频次】1
- 【下载频次】33