Mechanistic Study on the Oxidation of 4‐Hydroxycoumarin by Diperiodatonickelate(IV) in Aqueous Alkaline Medium

Abstract

The oxidation of 4-hydroxycoumarin (HDC) by diperiodato- nickelate(IV) (DPN) in aqueous alkaline medium at a constant ionic strength of 1.0 mol dm-3was studied spectrophotometrically at 298 K. The reaction between DPN and 4-hydroxycoumarin in alkaline medium exhibits 1:3 stoichiometry (HDC: DPN). The reaction is of first order in [DPN] and has less than unit order in [HDC] and fractional order in [alkali]. The oxidation reaction in alkaline medium has been shown to proceed via a DPN- 4-hydroxycoumarin complex, which decomposes slowly in a rate-determining step followed by other fast steps to give the products. The main products were identified by spot test, IR,1HNMR studies. The reaction constants involved in the different steps of the mechanism were calculated. The activation parameters with respect to slow step of the mechanism were computed and discussed and thermodynamic quantities were also determined.

Ru(III)/Os(VIII) Catalysed Oxidation of Gabapentin (Neurotin) Drug by Diperiodatoargentate(III) in Aqueous Alkaline Medium (Stopped Flow Technique): A Comparative Study

“…in solution was detected by adding KCl solution to the reaction mixture, which produced white turbidity due to the formation of AgCl. The products obtained are similar to that for uncatalysed reaction [14].…”

“…Osmium(VIII) and ruthenium(III) catalysis in redox reactions involve several complexes, different oxidation states of osmium/ruthenium, etc. The uncatalysed reaction of oxidation of gabapentin by DPA has been studied [14]. We have observed that osmium(VIII) and ruthenium(III) catalyze the oxidation of gabapentin by DPA in alkaline medium in micro amounts.…”

Electro-oxidation and determination of gabapentin at gold electrode

“…In a separate study by chemical oxidation of GP by a moderate oxidant diperiodatoargentate(III) gave the main product as 1-(hydroxymethyl)cyclohexaneaceticacid and based on the kinetic data the mechanism has been proposed with a free radical intervention [32]. But based on the cyclic voltammetric experiments, the number of electrons transferred (n) was calculated to be 1.0.…”

Kinetics and Mechanism of Oxidation of Carbenicillin by Copper (III) Periodate Complex in Aqueous Alkaline Medium

“…Transition metals can form stable complexes with polydentate ligands such as diperiodatocuprate (DPC-III) [21,22], diperiodatoargentate (DPA-III) [23], diperiodatonickelate (DPN-IV) [24], ditelluratocuprate (DTC-II) [25,26], and hexacyanoferrate (HCF-III) [27]. At first, Malatesta had synthesized DPC (III) more than a half century ago, and Panigrahi and Pathy [28] followed that method.…”