Insertion of Carbodiimide into the Ln−C σ-Bond of Organolanthanide Complexes. Synthesis, Reaction, and Characterization of Organolanthanide Amidinates (C₅H₅)₂Ln[<i>^t</i>BuNC(<i>ⁿ</i>Bu)N<i>^t</i>Bu] (Ln = Er, Gd, Y)

Abstract

The synthesis, structures, and reactivity of new lanthanocene complexes incorporating amidinate ligand [tBuNC(nBu)NtBu] are described. Treatment of Cp2LnnBu (Ln = Er (1), Y (2), Gd (3)) with N,N'-di-tert-butylcarbodiimide results in monoinsertion of carbodiimide into the Ln−C σ-bond to yield the title compounds Cp2Ln[tBuNC(nBu)NtBu] (Ln = Er (4), Y (5), Gd (6)). Complexes 4−6 were characterized by elemental analysis and IR and mass spectroscopies. The structures of complexes 4 and 5 were determined through X-ray single-crystal diffraction analysis. It is shown that compound 5 is a fine catalyst for cyclotrimerization of phenyl isocyanate.