REACTIVITY OF α-BENZOIN OXIME WITH TUNGSTEN(VI)

Abstract

In this work, we are presenting various aspects of the reactivity of α-benzoin oxime with tungsten(VI) by altering the pH of the aqueous tungsten salt solution and the ligand/metal ratio. The reactivity of an ethanolic solution of α-benzoin oxime with an aqueous solution of a tungsten salt in the VI oxidation state was investigated at two pH values (1 and 2.5) and various values of the ligand/metal ratio. Based on the experimental conditions, the reaction of α-benzoin oxime (H2L1) with tungsten(VI) leads to the formation of various complexes: (1) a white monomeric coordination complex of the formula [WO2(HL1)2].H2O; (2) a white dimeric coordination complex of the formula [W2O5(H2L1)2(HL1)2] in which HL1 is the deprotonated form of α-benzoin oxime, C6H5(C=NO−)(CHOH)C6H5; (3) a white dimeric coordination complex of the formula [W2O5(L3)2(HL3)2] in which HL3 is the hydrolyzed form, C6H5(C=O)(CHOH)-C6H5, of α-benzoin oxime.