Luminescence, CPL and magnetic properties of 1D enantiopure Ln 3+ complexes with ( S -) and ( R -) α-methoxyphenylacetate ligand.

The reaction of Ln(NO ₃ ) ₂ ·6H ₂ O (Ln = Eu, Tb, Dy and Sm) with ( R )-(-)-α-methoxyphenylacetic acid (R-HMPA) and 1,10-phenanthroline (phen) in EtOH/H ₂ O allows the isolation of 1D chiral compounds of formula [Ln(μ- R -MPA)( R -MPA) ₂ (phen)] _n in which Ln = Eu (R-Eu), Tb (R-Tb), Dy (R-Dy) and Sm (R-Sm). The same synthesis by using ( S )-(+)-α-methoxyphenylacetic acid (S-HMPA) instead of ( R )-(-)-α-methoxyphenylacetic acid allows the isolation of the enantiomeric compounds with formula [Ln(μ- S -MPA)( S -MPA) ₂ (phen)] _n where Ln = Eu (S-Eu), Tb (S-Tb), Dy (S-Dy) and Sm (S-Sm). Single crystal X-Ray diffraction measurements were performed for compounds R/S-Eu, R/S-Tb, S-Dy and S-Sm. The luminescence and the circular dichroism measured in the solid state are reported. All compounds show sensitized luminescence, notably the Eu ³⁺ and Tb ³⁺ ones, whose emission color can be perceived by the naked eye. For the Eu ³⁺ and Tb ³⁺ derivatives the quantum yield and the circular polarized luminescence have been measured. For the magnetic allowed transition ⁵ D ₀ → ⁷ F ₁ of the Eu ³⁺ compound, the anisotropy factor g _lum is ±0.013 (+for S-Eu). Also, magnetic properties of all compounds were studied with the Dy ³⁺ analogue showing slow relaxation of the magnetization under a direct current magnetic field of 1000 Oe.