Mixed-ligand complexes of trivalent lanthanides. Part 3. Complexes of heptafluorodimethyloctane-3,5-dione and pyrazine: syntheses and spectral studies

Abstract

The lanthanide(III) tris(heptafluorodimethyloctanedionates), [Ln(fod)₃], form solid adducts with pyrazine (pyz) resulting in an increase in co-ordination number of the lanthanides from 6 to 7. In these adducts pyrazine co-ordinates through only one of its nitrogen atoms. The praseodymium, europium, and ytterbium adducts have been investigated for their applicability as lanthanide shift reagents. The dipolar shift produced in the spectra of butanol, benzyl alcohol, and dibutyl ether is discussed. The complexes do not dissociate even in the presence of added substrates (alcohols or ether).