Reaction of gallium and indium with 4-(2-Thiazolylazo) resorcinol

Abstract

Gallium is shown to react with TAR to form 1:1 and 1:2 Ga:TAR species, elucidation of the nature of which is complicated by hydrolysis. The species GaR+ and GaHR(OH)+, where H2R is the free reagent, occur at pH 2.7–4.8 for solutions that are equimolar or contain excess of metal ion; GaHR2+ occurs at pH 2.13–2.86 with excess of metal ion. A 1:2 complex, probably GaR2−, exists in 30% aqueous ethanol medium at pH 5̃ if excess of ligand is present. The utility of the reaction for analysis is severely limited by the large number of interfering elements. Indium reacts similarly, forming a In RH2+ complex which is converted into the 1:2 complex by excess of reagent at pH 4.6.