The synthesis and characterisation of europium terpyridine-N-oxide complexes

Abstract

Europium complexes of a series of terpyridine-N-oxide ligands have been prepared and structurally characterised by crystallographic studies. While the addition of three equivalents of terpyridine-1-oxide or terpyridine-1,1′-bisoxide results in complexes with nine co-ordinate tricapped trigonal prismatic or monocapped square antiprismatic geometries, respectively, three equivalents of the terpyridine-1,1′,1′-trisoxide yields an unexpected 8 co-ordinate geometry. Luminescence studies of the three complexes in acetonitrile show a typical europium emission spectra, dominated by the ⁵D₀–⁷F₂ transition. While no simple trend in the relative quantum yields could be ascertained, the terpyridine-1-oxide complex was observed to have the most intense luminescence for this set of complexes.