Synthesis, structure, and catalytic reactions of 1,2-bis(indenyl)ethane-derived lanthanocenes

The synthesis and structure of meso-[ethylenebis(eta(5)-indenyl)]ytterbium(III) bis(trimethylsilyl)amide (6) and the syntheses of rac- and meso-[[ethylenebis(eta(5)-indenyl)]ytterbium(III) chloride][LiCl(Et2O)(2)] (4, 5) and rac- and meso-[ethylenebis(eta(5)-indenyl)lutetium(III) chloride][LiCl(Et2O)(2)] (7, 8) are reported. The complexes are synthesized by the metathesis of dilithiated 1,2-bis(indenyl)ethane with either YbCl3 or LuCl3 in THF followed by solvent exchange with diethyl ether to give [[ethylenebis(eta(5)-indenyl)]Ln(III) chloride][LiCl(Et2O)(2)] (Ln = Yb, Lu) in yields of 43% and 30%, respectively. In the Yb case, the major diastereomer formed is meso, while in the lutetium reaction, the rac diastereomer predominated. Complex 6 is synthesized by reaction of meso-[[ethylenebis(eta(5)-indenyl)]ytterbium(III) chloride][LiCl(Et2O)(2)] with NaN(TMS)(2); this material was characterized by X-ray diffraction. Complex 6 catalyzes the cyclic hydroamination of primary amino olefins in excellent yields.