Europium(ii) bis[tetrafluoro-2-(pentafluoroethoxy)ethanesulfonate] – structure and spectroscopic properties of a new near-UV emitter

Abstract

A new Eu(II) complex, [Eu(CF₃CF₂OCF₂CF₂SO₃)₂(H₂O)]_∞, was obtained by electrochemical reduction. It is polymeric and the Eu²⁺ cation is 8-coordinate (6 oxygen atoms from sulfonate groups and two water molecules, which form bridges between adjacent europium cations). The compound shows bright UV luminescence with maximum at 377.8 nm (26 470 cm⁻¹) at 77 K. In the excitation spectrum clear Fano resonances, attributed to the ⁶I_J, ⁶D_J and ⁶G_J multiplets, were observed.