Novel Contrast Agents for Magnetica Resonance Imaging - Synthesis and Characterization of the Ligand BOPTA and Its Ln(III) Complexes (Ln=Gd, La, Lu) - X-Ray Structure of Disodium (TPS-9-145337286-C-S)-[4-Carboxymethyl)-1-Phenyl-2-Oxa-5,8,11-Triazatridecan-13-Oato(5-)]Gadolinate(2-) i a Mixture with Its Enantiomer