THEORETICAL-MODEL FOR THE PREDICTION OF ELECTRONIC-SPECTRA OF LANTHANIDE COMPLEXES

A technique is introduced for the theoretical prediction of electronic spectra of lanthanide complexes by replacing the metal ion by a point charge with the ligands held in their positions as determined by the SMLC/AM1, and by computing the theoretical spectra via the intermediat e neglect of differential overlap/spectroscopic-configuration interact ion (INDO/S-CI). As a test case, we report the absorption spectrum of tris(picolinate-N-oxide) (2,2': 6',2 ''-terpyridine) of Eu-III complex which has been synthesized in our laboratory. The predicted absorptio n spectra (complex and free ligands) compare well with the UV region e xperimental data. Moreover, the computed triplet energy levels display transitions near 470 and 560 nm which are due to the N-oxide and whic h may be relevant for the luminescence.