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Updated: Dec 18, 2025

Preparation, Purification, and Characterization of Lanthanide Complexes for Use as Contrast Agents for Magnetic Resonance Imaging
Published on: July 21, 2011
A Family of Highly Emissive Lanthanide Complexes Constructed with 6-(Diphenylphosphoryl)picolinate
Chen Wei1, Boxun Sun1, Zifeng Zhao1
1Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
Abstract:
We report a novel family of lanthanide complexes Ln(DPPOP)3 (Ln = Pr, Nd, Sm, Eu, Tb, Dy, Er, and Yb) employing anionic tridentate (O∧N∧O) ligand 6-(diphenylphosphoryl)picolinate (DPPOP). Crystal structures of the complexes reveal that each lanthanide ion is nine-coordinated by three tridentate ligands. In the crystals, 1D channels are found, which can absorb and eliminate water reversibly. DPPOP possesses high triplet energy and can sensitize a series of lanthanide ions. An energy transfer mechanism is proposed through the higher excited states of the lanthanide ions. In the solid state, remarkably high quantum yields in the visible range are obtained: 81% for Eu(III), 97% for Tb(III), 13% for Dy(III), and 4% for Sm(III) complex.
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