{"title":"异烟肼与五氰酸盐阴离子取代络合物[Ru(CN)5INH]3−的动力学及形成机理","authors":"Rupali Yadav, R. Naik","doi":"10.1177/1468678319825737","DOIUrl":null,"url":null,"abstract":"The formation kinetics of the complex, [Ru(CN)5INH]3−, formed through the ligand substitution reaction between isoniazid (INH) and aquapentacyanoruthenate(II) ([Ru(CN)5H2O]3−), have been investigated, under pseudo first-order conditions, as a function of concentrations of [INH] and [Ru(CN)5H2O]3−, ionic strength and temperature at pH = 4.0 ± 0.02 in 0.2 M NaClO4 spectrophotometrically at 502 nm (λmax of intense yellow colour product [Ru(CN)5INH]3−) corresponding to metal-to-ligand charge-transfer transitions, in aqueous medium. The pseudo first-order condition was maintained by taking at least 10% excess of [INH] over [Ru(CN)5H2O]3−. The stoichiometry of the reaction product was found to be 1:1 which was further supported and characterized using elemental analysis, infrared, nuclear magnetic resonance and mass spectrometric techniques. Thermodynamic and kinetic parameters have also been computed, using the Eyring equation, and the values of ΔH≠, Ea, ΔG≠ and ΔS≠ were found to be 47.3 kJ mol−1, 49.8 kJ mol−1, −8.62 kJ mol−1 and 187.6 J K−1mol−1, respectively. The reaction was found to obey first-order kinetics with respect to [INH]. It exhibited a negative salt effect on the rate upon variation of ionic strength of the medium. A tentative mechanistic scheme was proposed on the basis of experimental findings.","PeriodicalId":20859,"journal":{"name":"Progress in Reaction Kinetics and Mechanism","volume":null,"pages":null},"PeriodicalIF":2.1000,"publicationDate":"2019-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Kinetics and mechanism of formation of the complex [Ru(CN)5INH]3− through the ligand substitution reaction between the aquapentacyanoruthenate(II) anion and isoniazid\",\"authors\":\"Rupali Yadav, R. Naik\",\"doi\":\"10.1177/1468678319825737\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"The formation kinetics of the complex, [Ru(CN)5INH]3−, formed through the ligand substitution reaction between isoniazid (INH) and aquapentacyanoruthenate(II) ([Ru(CN)5H2O]3−), have been investigated, under pseudo first-order conditions, as a function of concentrations of [INH] and [Ru(CN)5H2O]3−, ionic strength and temperature at pH = 4.0 ± 0.02 in 0.2 M NaClO4 spectrophotometrically at 502 nm (λmax of intense yellow colour product [Ru(CN)5INH]3−) corresponding to metal-to-ligand charge-transfer transitions, in aqueous medium. The pseudo first-order condition was maintained by taking at least 10% excess of [INH] over [Ru(CN)5H2O]3−. The stoichiometry of the reaction product was found to be 1:1 which was further supported and characterized using elemental analysis, infrared, nuclear magnetic resonance and mass spectrometric techniques. Thermodynamic and kinetic parameters have also been computed, using the Eyring equation, and the values of ΔH≠, Ea, ΔG≠ and ΔS≠ were found to be 47.3 kJ mol−1, 49.8 kJ mol−1, −8.62 kJ mol−1 and 187.6 J K−1mol−1, respectively. The reaction was found to obey first-order kinetics with respect to [INH]. It exhibited a negative salt effect on the rate upon variation of ionic strength of the medium. A tentative mechanistic scheme was proposed on the basis of experimental findings.\",\"PeriodicalId\":20859,\"journal\":{\"name\":\"Progress in Reaction Kinetics and Mechanism\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":2.1000,\"publicationDate\":\"2019-06-26\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Progress in Reaction Kinetics and Mechanism\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://doi.org/10.1177/1468678319825737\",\"RegionNum\":4,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"CHEMISTRY, PHYSICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Progress in Reaction Kinetics and Mechanism","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1177/1468678319825737","RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
摘要
在拟一阶条件下,研究了异烟肼(INH)与aquentacyanorthenate (II) ([Ru(CN)5H2O]3−)配体取代反应形成的络合物[Ru(CN)5INH]3−的形成动力学,以及[INH]和[Ru(CN)5H2O]3−浓度的函数。离子强度和pH = 4.0±0.02时0.2 M NaClO4在502 nm(强黄色产物[Ru(CN)5INH]3−的λmax)对应于水介质中金属到配体的电荷转移转变。当[INH]比[Ru(CN)5H2O]3−至少多10%时,伪一阶条件得以维持。通过元素分析、红外、核磁共振和质谱等技术对反应产物进行了进一步的支持和表征,发现其化学计量比为1:1。利用Eyring方程计算了反应的热力学和动力学参数,得到ΔH≠、Ea、ΔG≠和ΔS≠的值分别为47.3 kJ mol−1、49.8 kJ mol−1、- 8.62 kJ mol−1和187.6 jk−1mol−1。发现该反应在[INH]方面服从一级动力学。它对介质离子强度的变化率表现出负的盐效应。根据实验结果,提出了一种初步的机理方案。
Kinetics and mechanism of formation of the complex [Ru(CN)5INH]3− through the ligand substitution reaction between the aquapentacyanoruthenate(II) anion and isoniazid
The formation kinetics of the complex, [Ru(CN)5INH]3−, formed through the ligand substitution reaction between isoniazid (INH) and aquapentacyanoruthenate(II) ([Ru(CN)5H2O]3−), have been investigated, under pseudo first-order conditions, as a function of concentrations of [INH] and [Ru(CN)5H2O]3−, ionic strength and temperature at pH = 4.0 ± 0.02 in 0.2 M NaClO4 spectrophotometrically at 502 nm (λmax of intense yellow colour product [Ru(CN)5INH]3−) corresponding to metal-to-ligand charge-transfer transitions, in aqueous medium. The pseudo first-order condition was maintained by taking at least 10% excess of [INH] over [Ru(CN)5H2O]3−. The stoichiometry of the reaction product was found to be 1:1 which was further supported and characterized using elemental analysis, infrared, nuclear magnetic resonance and mass spectrometric techniques. Thermodynamic and kinetic parameters have also been computed, using the Eyring equation, and the values of ΔH≠, Ea, ΔG≠ and ΔS≠ were found to be 47.3 kJ mol−1, 49.8 kJ mol−1, −8.62 kJ mol−1 and 187.6 J K−1mol−1, respectively. The reaction was found to obey first-order kinetics with respect to [INH]. It exhibited a negative salt effect on the rate upon variation of ionic strength of the medium. A tentative mechanistic scheme was proposed on the basis of experimental findings.