Reactivity of some sugars and sugar phosphates towards gold(III) in sodiumacetate-acetic acid buffer medium

The kinetics of the oxidation of some aldoses and aldose phosphates have be en studied spectrophotometrically in sodium acetate-acetic acid buffer medi um at different temperatures. The reactions are first order with respect to [Au(III)] and [substrate]. Both H+ and Cl- ions retard the reaction. The r eactions appear to involve different gold(III) species, viz. AuCl4, AuCl3(O H2) and AuCl3(OH)(-). The results are interpreted in terms of the probable intermediate formation of free radicals and Au(II). Aldoses react with gold (III) in the order: triose > tetrose > pentose > hexose. The sugar phosphat es react with gold(III) at a faster rate than the parent sugars except gluc ose-1-phosphate, which reacts at slower rates than glucose. A tentative rea ction mechanism leading to the formation of products has been suggested. (C ) 2001 Elsevier Science Ltd. All rights reserved.