Synthesis and photophysical properties of rare earth complexes bearing silanediamido ligands Me₂Si(NAryl)₂²⁻ (Aryl = Dipp, Mes)

A series of rare earth (RE) chloride complexes bearing silanediamido ligands (LAryl)2− = Me2Si(NAryl)22− with bulky substituents, Aryl = mesityl (Mes), and 2,6-diisopropylphenyl (Dipp) was synthesized by salt metathesis reactions. Binuclear species [{RE(LAryl)(thf)2}2(μ-Cl)2] (REAryl; RE = Y, Gd, Tb, Sm, Aryl = Dipp; RE = Y, Gd, Tb, Aryl = Mes) crystallize from non-polar solvents. Deprotonation reactions of proligands H2LAryl by KH and n-BuLi are compared, and the advantages of both approaches are discussed. Formation of ate complexes [{RE(LAryl)(thf)(μ-Cl)2Li(thf)3}2(μ-Cl)2] (RE = Y, Tb) was detected when using n-BuLi. Recrystallization of YDipp from pure thf led to the monomerization to the [Y(LDipp)Cl(thf)3] complex. Energies of the triplet states were determined for both ligands from the photoluminescence (PL) spectra of Gd complexes. The PL of Tb complexes in the solid state and in a solution was studied, showing substantial sensitization by the (LAryl)2− ligands.