Theoretical model for the prediction of electronic spectra of lanthanide complexes

Abstract

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 intermediate neglect of differential overlap/spectroscopic-configuration interaction (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 absorption spectra (complex and free ligands) compare well with the UV region experimental data. Moreover, the computed triplet energy levels display transitions near 470 and 560 nm which are due to the N-oxide and which may be relevant for the luminescence.