Structure, Volatility, and Luminescence of Phenanthroline Adducts with Lanthanide Tris-Dipivaloylmethanates

Abstract

A series of Ln(III) tris-dipivaloylmethanates with phenanthroline with the composition Ln(thd)3Phen (Ln = Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb) is synthesized. It is found that all adducts are isostructural with previously known La(thd)3Phen, Tb(thd)3Phen, and Dy(thd)3Phen complexes. Crystal structures of Sm(thd)3Phen (I) and Eu(thd)3Phen (II) complexes are determined at 150(2) K (space group $$P\overline 1 $$ , a = 10.8590(5) A, b = 12.3049(6) A, c = 18.4479(10) A, α = 80.210(2)°, β = 87.499(2)°, γ = 68.799(2)°, V = 2264.3(2) A3, Z = 2; space group $$P\overline 1 $$ , a = 10.8788(3) A, b = 12.3009(3) A, c = 18.4309(5) A, α = 80.3644(9)°, β = 87.5440(10)°, γ = 68.7376(8)°, V = 2265.7(1) A3, Z = 2 respectively). Crystal structures of I and II consist of isolated Ln(thd)3Phen molecules (Ln = Sm(III), Eu(III)). The highest luminescence quantum yields for this series of adducts are established for Eu(thd)3Phen (10%) and Sm(thd)3Phen (1.5%). Thermogravimetric studies show that the volatility of adducts weakly increases from Pr(thd)3Phen to Yb(thd)3Phen. Their melting points are close to the reported data.