Characteristic Structures and Photophysical Properties of Nine-Coordinate Europium(III) Complexes with Tandem-Connected Tridentate Phosphane Oxide Ligands

Structures and photophysical properties of f‐block metal complexes with tandem‐connected tridentate phosphane oxide ligands, {bis[o‐(diphenylphosphoryl)phenyl]phenylphosphane oxide}tris(hexafluoroacetylacetonato)europium(III) [Eu(hfa)3(DPPPO)], {bis[o‐(diphenylphosphoryl)pyridyl]phenylphosphane oxide}tris(hexafluoroacetylacetonato)europium(III) [Eu(hfa)3(DPPYPO)] and {bis[o‐(diphenylphosphoryl)benzothienyl]phenylphosphane oxide}tris(hexafluoroacetylacetonato)europium(III) [Eu(hfa)3(DPBTPO)], are reported. The coordination geometries of Eu(hfa)3(DPPPO) and Eu(hfa)3(DPBTPO) provide characteristic distorted, capped square antiprism structures with nine‐coordinate oxygen atoms. The emission properties related to the electric transition are characterized by the emission spectra, the emission quantum yields, the emission lifetimes, and the radiative and non‐radiative rate constants. EuIII complexes with tridentate phosphane oxide ligands offer relatively high emission quantum yields (> 60 % in [D6]acetone) due to their low‐symmetric and low‐frequency vibrational structures. The electric dipole transition intensities in the emission spectra depend on the chemical structures of tridentate phosphane oxides. The characteristic photophysical properties of polyhedral f‐block metal complexes, nine‐coordinate EuIII complexes with tridentate phosphane oxide, are demonstrated for the first time.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) The characteristic structures and photophysical properties of polyhedral f‐block metal complexes, nine‐coordinate EuIII complexes with tridentate phosphane oxide, are demonstrated for the first time.