<span style="font-size:11.0pt;mso-bidi-font-size: 10.0pt;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-GB;mso-fareast-language:EN-US;mso-bidi-language:AR-SA" lang="EN-GB">Silver(I)-catalysed abstraction of coordinated cyanide in hexacyanoferrate(II) by D-penicillamine in aqueous medium</span>

Abstract

<span style="font-size:11.0pt;mso-bidi-font-size: 10.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" letter-spacing:-.1pt;mso-ansi-language:en-gb;mso-fareast-language:en-us;="" mso-bidi-language:ar-sa"="" lang="EN-GB">The kinetics and mechanism of Ag(I)-catalyzed exchange of coordinated cyanide in hexacyanoferrate(II) by <span style="font-size:11.0pt;mso-bidi-font-size:10.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" letter-spacing:-.2pt;mso-ansi-language:en-gb;mso-fareast-language:en-us;="" mso-bidi-language:ar-sa"="" lang="EN-GB">D-penicillamine (D-PA) have been monitored by following the appearance of blue colored complex [Fe(CN)₅(D-PA)]^3-at 423 nm,<span style="font-size:11.0pt;mso-bidi-font-size:10.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" letter-spacing:-.1pt;mso-ansi-language:en-gb;mso-fareast-language:en-us;="" mso-bidi-language:ar-sa"="" lang="EN-GB"> corresponding to metal to ligand charge transfer (MLCT) transition. The effect of <i>p</i>H, ionic strength, catalyst concentration and concentration of hexacyanoferrate(II) and D-penicillamine on the rate of reaction has also studied and explained. The findings indicate first order dependence each in [Fe(CN)₆]^4- and [D-PA]. The composition of the complex formed has been established to be 1:1 by mole ratio and slope ratio method. The kinetic observations suggest that the substitution follows an interchange dissociative (I_d) mechanism which proceeds <span style="mso-bidi-font-style:italic">via formation of a solvent bound intermediate. The activation parameters ΔH^#and ΔS^#have also been calculated and provided in support of the proposed mechanistic scheme. It is observed first time that the drug D-penicillamine used acts as a potential ligand and it can replace the coordinated cyanide in hexacyanoferrate(II).</span></span></span></span>