Facile construction of novel organolanthanide square-planar macrocycles through addition of carbodiimide to an amino group

The reactivity of lanthanocene derivatives containing the p-aminothiophenolate ligand towards carbodiimide was examined. Reaction of Cp2Ln(p-SC6H4NH2)(THF) with RN=C=NR in THF at room temperature gave four novel organolanthanide guanidinate complexes [Cp2Ln(p-SC6H4N(H)C(NHR)=NR)]4 (R = iPr, Ln = Yb (1a), Er (2a); R = Cy, Ln = Yb (2a), Er (2b)), formed by the addition of the C[double bond, length as m-dash]N double bonds of the carbodiimide molecule to the para-position amino group. Their unique square-planar macrocycle structures have been determined through X-ray single-crystal diffraction analysis. This result provides a potential method for the construction of organolanthanide macrocycles.