Multinuclear magnetic resonance study of the complexation of lanthanide(III) cations with tetrahydropyran-2-methanol

Abstract

The complexation of lanthande(III) ions in tetrahydropyran-2-methanol (thpm) and in thpm–water mixtures has been investigated using ¹³⁹La, ³⁵Cl, ¹⁷O and ¹³C shift and relaxation measurements. The ligand thpm binds in a didentate manner, forming a 2 : 1 complex containing inner-sphere chlorides, when used as the sole solvent. The location of the gadolinium(III) ion with respect to the thpm ligand in the [Gd(thpm)₂]³⁺ complex, as determined from ¹³C longitudinal relaxation-rate measurements, confirmed the didentate binding of thpm. Lanthanide(III) ions bind D₂O preferentially in thpm–D₂O mixtures.