Synthesis, structure, and diverse catalytic activities of [ethylenebis(indenyl)]lanthanide(III) amides on N-H and C-H addition to carbodiimides and ε-caprolactone polymerization

The simple silylamine elimination reaction of ethylenebis(indene) with the lanthanide amides [(Me3Si)(2)N](3)Ln(mu-Cl)Li(THF)(3) produced the [ethylenebis(eta(5)-indenyl)][bis(trimethylsilyl)amido]lanthanide(III) complexes (EBI)LnN(TMS)(2) (Ln = Y (1), Sm (2), Yb (3)), which exhibited diverse catalytic activities on the addition of the N-H bond of amines and the C-H bond of terminal alkynes to the carbodiimides and on the ring-opening polymerization of epsilon-caprolactone as well. The new complexes 1 and 2 were fully characterized by spectroscopic methods, elemental analyses, and X-ray crystallographic analyses. This work offers a straightforward, highly atom efficient route for the syntheses of substituted guanidines and propiolamidines, and it represents the first application of readily accessible lanthanocene amides to these reactions.