A novel structure analysis method for lanthanide complex: None paramagnetic shift tri-lanthanide mixture method

A new structure analysis method for lanthanide complexes was proposed, that is, none paramagnetic shift tri-lanthanide mixture method. It was found that the paramagnetic induced shift could be cancelled by mixing three kinds of paramagnetic lanthanide ions in appropriate proportion. As a result, the chelating sites would be seen simplely from the half widths and the relative distances between lanthanide ion and the ligand nucleus could be calculated from the relaxation time(T₁) or the half width. Care should be addressed that the analysis method is suitable for the systems in which intramolecular arrangements and intermolecular ligand exchanges are relatively fast on NMR time scale used.