Insertion of carbodiimide into the Ln-C σ-bond of organolanthanide complexes.: Synthesis, reaction, and characterization of organolanthanide amidinates (C5H5)2Ln[tBuN-C(nBu) - NtBu] (Ln = Er, Gd, Y)

The synthesis, structures, and reactivity of new lanthanocene complexes incorporating amidinate ligand [(BuN)-Bu-t - C(Bu-n) - (NBu)-Bu-t] are described. Treatment of Cp(2)Ln(n)Bu (Ln = Er (1), Y (2), Gd (3)) with N,N-di-tert-butylcarbodiimide results in monoinsertion of carbodiimide into the Ln-C sigma-bond to yield the title compounds Cp(2)Ln[(BuN)-Bu-t-C(Bu-n) - (NBu)-Bu-t] (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.