Lanthanide complexes of a linear heptadentate ligand. Potential contrast agents for magnetic resonance imaging

Abstract

The complexes [Ln{2-OC 6H 4-CHNCH 2(CH 2NHCH 2) 3-CH 2NCHC 6H 4O-2′}(H 2O)]Cl· nH 2O (Ln = Lu, Gd) have been synthesized. The X-ray crystal structure of the lutetium complex reveals an eight-coordinate lutetium ion bound to two oxygens and five nitrogen atoms in the ligands and to a water molecule. The relaxivity of the gadolinium complex is comparable to that of [Gd(DTPA)(H 2O)] 2−.