SPECTROSCOPIC STUDIES OF RARE EARTH CHELATES

ABS>Intramolecular energy transfer in rare earth chelates is discussed and the role of the triplet states of the complexes in this type of energy migration is reviewed briefly. A spectroscopic study of the chelates of La/sup 3+/, Pr/sup 3+/, Sm/sup 3+/, Eu/sup 3+/, and Gd/sup 3+/ with o- hydroxybenzophenone is reported. Luminescence spectra (at 77 deg K) of these compounds are presented and the triplet state energies of the chelates and their dissociation products were determined utilizing energy transier as an aid in interpreting the complicated luminescences observed. Very week line'' emission from the coordinated Pr/sup 3+/ ion is reported and selective excitation of the / sup 1/D/sub 2/, /sup 3/P/sub 0/, and /sup 3/P/sub 1/ resonance leve ls of this ion via intramolecular energy transfer is demonstrated. (auth)