The tungsten(IV) aqua ion; reduction studies and detection of aquachloro complexes of [W 3(μ 3-O)(μ 2-O) 3] 4+ by oxygen-17 and tungsten-183 NMR spectroscopy

Abstract

Oxygen-17 and tungsten-183 NMR studies on solutions of orange tungsten(IV), prepared in 2 M p-toluenesulphonic acid (Hpts) solution via acid catalyzed hydrolysis of potassium hexachlorotungstate(IV) in 2 M Hpts followed by treatment with a single DOWEX 50W X2 cation-exchange column, confirm the formation of the species; [W 3(μ 3-O)(μ 2-O) 3(OH 2) 8Cl] 3+ as major product in addition to [W 3(μ 3-O)(μ 2-O) 3(OH 2) 9] 4+ under these conditions in a manner not possible by spectrophotometric means. Further characterization of the green W(III,III,IV) mixed-valence reduction product has also been carried out with in addition an estimation of the formal reduction potential for the W(IV) 3/W(III,III,IV) redox couple.