Structure of lanthanide semiquinolates with nitrogen-containing ligands

Molecular and crystal structures are determined for a series of mixed-ligand mononuclear compounds of lanthanides (Ln) with the 3,6-di(tert-butyl)-1,2-benzoquinone (SQ) anion radical and bidentate nitrogen-containing ligands (L) of the composition [Ln(SQ) ₃(L)], where Ln is Tb or Dy, L is 2,2′-bipyridine (bipy); Ln is Eu, L is 1,10-phenanthroline (phen) or N,N,N′,N′-tetramethylethylenediamine (tmen). It is confirmed that the introduction of bidentate L significantly increases the stability of lanthanide semiquinolates in both liquid and solid phases.