Boronic acid-facilitated ¦Á-hydroxy-carboxylate anion transfer at liquid/liquid electrode systems: the EICrev mechanism
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- 作者：Najoua Katif ; Rachel A. Harries ; Andrew M. Kelly ; John S. Fossey ; Tony D. James and Frank Marken
- 关键词：Boronic acid ; Carbohydrate ; α ; Hydroxy carboxylic acid ; Voltammetry ; Liquid/liquid interface ; Electrocatalysis ; Sensors
- 刊名：Journal of Solid State Electrochemistry
- 出版年：2009
- 出版时间：October, 2009
- 年：2009
- 卷：13
- 期：10
- 页码：1475-1482
- 全文大小：372.1 KB
文摘
The transfer of the α-hydroxy-carboxylates of glycolic, lactic, mandelic and gluconic acid from the aqueous electrolyte phase into an organic 4-(3-phenylpropyl)-pyridine (PPP) phase is studied at a triple-phase boundary electrode system. The tetraphenylporphyrinato complex MnTPP dissolved in PPP is employed to drive the anion transfer reaction and naphthalene-2-boronic acid (NBA) is employed as a facilitator. In the absence of a facilitator, the ability of α-hydroxy-carboxylates to transfer into the organic phase improves, consistent with hydrophobicity considerations giving relative transfer potentials (for aqueous 0.1 M solution) of gluconate>glycolate>lactate>mandelate. In the presence of NBA, a shift of the reversible transfer potential to more negative values is indicating fast reversible binding (the mechanism for the electrode process is EICrev) and the binding constants are determined as K glycolate = 2 M−1, K mandelate = 60 M−1, K lactate = 130 M−1 and K gluconate = 2,000 M−1. The surprisingly strong interaction for gluconate is rationalised based on secondary interactions between the gluconate anion and NBA.