Complexation of vanadium(V) oxoanion with ethanolamine derivatives in solution and in a cross-linked polymer

Complex formation between vanadate and various ethanolamine derivatives (ethanolamine, diethanolamine, methyldiethanolamine, triethanolamine and ECTEOLA-Cellulose) has been examined in detail by using ⁵¹V NMR spectroscopy. Vanadate binds with ethanolamine to form 1:1 (O)-monodentate and (N,O)-bidentate complexes which are protonated and deprotonated forms, respectively. Ethanolamine undergoes a comparatively weak interaction with vanadate relative to the other ligands. ⁵¹V NMR spectra clearly show that vanadate reacts with the functional group of ECTEOLA-Cellulose, as well as diethanolamine, methyldiethanolamine and triethanolamine, which are analogues of the functional groups of ECTEOLA-Cellulose, to form the -1 charged 1:1 (N,O,O)-tridentate complex. In addition to anion exchange interaction of monovanadate and isopolyvanadate anions with the protonated functional group, in the alkaline region the adsorbability of vanadium(V) onto ECTEOLA-Cellulose is a consequence of the complexation of vanadate with the functional group. The formation constant of the (N,O,O) complex with ECTEOLA-Cellulose was estimated to be logβ̄(N,O,O)=3.6, which was almost the same as those with the analogues of the functional group.