Aluminium complexes in methanol–water mixture as studied by 27Al NMR nuclear magnetic resonance

Abstract

27Al NMR spectroscopy can be used for study of coordination and solvation in both aqueous and non-aqueous solutions. Various octahedral and tetrahedral aluminium complexes have been proved to exist in solution by 1H and 27Al NMR spectroscopy. 27Al nuclear magnetic resonance (NMR) spectroscopy also can be used to determine thermodynamic properties of complexes in the solution. The formation of [Al(OH) 4− n (CH 3OH) n ] ( n−1)+ ( n = 1, 2, 3 and 4) species through the reaction of aluminate anion with methanol has been investigated by 27Al NMR spectroscopy. 27Al NMR spectra reveal evidence for Al bound to one, two, three and four CH 3OH, the production of aluminate species is affected by the MeOH/H 2O. Results obtained from 2D EXSY experiments clearly confirm there are exchanges among the species.