Luminescent properties of europium complexes with bis(diphenylphosphino)alkane dioxides.

Eu(NO(3))(3) · 5H(2)O and EuCl(3) · 6H(2)O were allowed to react with bis(diphenylphosphino)alkane dioxides Ph(2)P(O)(CH(2))(n) P(O)Ph(2)(n = 2, 4, 6) to obtain polymeric and binuclear complexes. The prepared compounds were structurally characterized by X-ray diffraction. Luminescence measurements (emission and excitation spectra, quantum yields, lifetimes) were compared with crystallographic data in order to find a relationship between luminescent properties of the Eu(III) complexes and their structures. The Eu(III) polymers, especially [Eu(dpphO(2))(2)Cl(2)](+) Cl(-)}(n), have shown extremely long luminescence lifetimes, up to 3.73 ms, as a result of a highly protecting hydrophobic shield.