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. §Dedicated to Professor Georgy A. Domrachev on the occasion of his 70th birthday