Dependence of the mutual ligand arrangement in guanidinate complexes of lanthanoids on the ligand solid angles

Mutual ligand arrangement in binuclear lanthanoid complexes of the type [Gu₂Ln(μ-H)]₂, [Gu₂Ln(μ-Cl)]₂, and Gu₂Ln(μ-Cl)₂Li(THF)₂, where Gu is a substituted guanidinato ligand, is quantitatively analyzed based on the ligand solid angle approach. In complexes of Nd, Sm, and Gd the Gu ligands shield up to 87% of the metal and the bidentate ligands on opposite metal centers are in the eclipsed arrangement; in complexes of lanthanoids with smaller ionic radii Y, Yb, and Lu the Gu ligands shield over 88.3% of the metal surface and their staggered conformation is observed. The ligand solid angle approach is illustrated and its application to describing multidentate ligands is demonstrated.