The [Dy(H2O)n(CyDTA)]− complex as an NMR paramagnetic relaxational temperature probe in an aqueous solution and bicelles

Abstract

The relaxation properties of the [Dy(H₂O)_n(CyDTA)]⁻ complex were studied by ¹H NMR using methods based on the analysis of spin–spin relaxation rates. It is found that a significant temperature-dependent broadening of the NMR signals is due to the presence of the Curie-spin contribution to the increase in the spin–spin relaxation rate (both on nuclei of ligands and residual protons of D₂O). The [Dy(H₂O)_n(CyDTA)]⁻ penetrates into the lipid membrane in DMPC/DHPC bicelles (according to NOESY experiments). This compound can be used for the design of thermosensitive NMR probes aimed at determining the local temperature in aqueous media and advanced diagnostics of diseases using MRI technologies.