Kinetic and mechanistic studies on the interaction of thiosemicarbazide <span style="font-size:14.0pt;font-family:"Times New Roman";mso-fareast-font-family: "Times New Roman";mso-ansi-language:EN-US;mso-fareast-language:EN-US; mso-bidi-language:AR-SA">with <i>cis </i>- diaquaethylenediamine platinum (II) ion</span>

Abstract

Kinetics of interaction of thiosemicarbazide with [Pt(en)(H₂O₂)²⁺ has been studied spectrophotometrically as a function of [Pt(en)(H₂O₂)²⁺ , [thiosemicarbazide] and temperature at a particular <i style="mso-bidi-font-style:normal">p</i>H(4.0) where the substrate complex exists predominantly as the diaqua species and the ligand thiosemicarbazide as a neutral molecule. Th<span style="font-size:14.0pt;font-family:HiddenHorzOCR; mso-bidi-font-family:HiddenHorzOCR">e interaction reaction shows distinct two step consecutive process, the first step is the ligand assisted anation and the second step is the chelation step. The activation parameters for both the steps are evaluated (Δ<i>H</i>_{<span style="font-size:14.0pt;font-family:Arial;mso-bidi-font-style:italic">1</span>}<i>^≠</i><i>= </i>35 .69 ± 0.80 k J mol ^-1, ΔS_{<span style="font-size:14.0pt;font-family:Arial;mso-bidi-font-style:italic">1</span>}<i>^≠</i><i> </i>= -166± 2.54 JK^-1 mol ^-1 and Δ<i>H</i>_{<span style="font-size:14.0pt;font-family:Arial;mso-bidi-font-style:italic">2</span>}<i>^≠</i>= 44.54 ± 1.32 k J mol ^-1 , ΔS_{<span style="font-size:14.0pt;font-family:Arial;mso-bidi-font-style:italic">2</span>}<i>^≠</i><i> </i>= -182 ±

<span style="font-size:14.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:="" "times="" roman";mso-ansi-language:en-us;mso-fareast-language:en-us;="" mso-bidi-language:ar-sa"="">4. 18 JK^-1 mol ^-1 ).</span></span>