Inclusion complexes between β‐cyclodextrin and β‐benzyloxy‐α‐propionic derivatives of paramagnetic DOTA‐ and DPTA‐Gd(III) complexes

The addition of β‐cyclodextrin to a solution containing β‐benzyloxy‐α‐propionic‐substituted DOTA‐ and DTPA‐Gd(III) complexes leads to the formation of inclusion compounds whose equilibrium constants have been determined by NMR titrations. The main effect associated with the formation of this ‘host‐uest’ interaction is a marked elongation of the molecular reorientational time, τ_r, which in turn results in increased solvent proton relaxation rates.