Application of multinuclear magnetic resonance spectroscopy to solvation and aggregation phenomena in solution. Plenary lecture

Abstract

Owing to its sensitivity to solute–solvent interactions, nuclear magnetic resonance (NMR) has proved to be an invaluable tool for the study of solvation shells around dissolved species, mainly metal ions, and to detect the presence of aggregates in homogeneous or microheterogeneous solutions. Such structures are extremely labile, and the NMR methodology used to detect them is highly dependent on their mean lifetime and on the magnetic properties of the solution i.e., whether it is dia- or paramegnetic. Structural and dynamic information can be obtained from nuclear parameters and NMR patterns of nuclei from either the solvent or the solute. Examples of investigations are given using, mainly, solvates of metal ions with organophosphorus non-ionic ligands (alkyl phosphates, phosphonates, mono or β-diphosphoramides) and a variety of resonant nuclei, mainly ³¹P and ¹H, but also ¹³C, ²⁷Al, ⁹Be, ⁷¹Ga, ⁶³Cu and ⁶⁵Cu, ¹¹³Cd, ⁶⁷Zn, ³⁵Cl, ¹⁷O, ¹⁵N. Some possibilities for practical applications are outlined from a few typical examples: liquid–liquid extraction of uranyl ions, titration of rare earths in solutions, solubility of oxygen in fluorocarbons, micellization in non-aqueous solvents.