The amide protons of an ytterbium(III) dota tetraamide complex act as efficient antennae for transfer of magnetization to bulk water

Contrast agent for magnetic resonance imaging: The exchangeable amide protons in the Yb³⁺ complex of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetamide (see crystal structure) act as efficient antennae for transfer of saturated spins to bulk water. Saturation of all eight protons in a 5 mm solution of this complex results in a 38% decrease in the signal intensity of bulk water. The compound thus has promise as a magnetization-transfer contrast agent for magnetic resonance imaging.