The Relationship between NMR Chemical Shifts of Thermally Polarized and Hyperpolarized ⁸⁹Y Complexes and Their Solution Structures

Recently developed dynamic nuclear polarization (DNP) technology offers the potential of increasing the NMR sensitivity of even rare nuclei for biological imaging applications. Hyperpolarized 89 Y is an ideal candidate because of its narrow NMR linewidth, favorable spin quantum number ( I = ), and long longitudinal relaxation times ( T 1 ). Strong NMR signals were detected in hyperpolarized 89 Y samples of a variety of yttrium complexes. A dataset of 89 Y NMR data composed of 23 complexes with polyaminocarboxylate ligands was obtained using hyperpolarized 89 Y measurements or 1 H, 89 Y‐HMQC spectroscopy. These data were used to derive an empirical equation that describes the correlation between the 89 Y chemical shift and the chemical structure of the complexes. This empirical correlation serves as a guide for the design of 89 Y sensors. Relativistic (DKH2) DFT calculations were found to predict the experimental 89 Y chemical shifts to a rather good accuracy.