Synthesis, Characterization, and Catalytic Activity of Some Neodymium(III), Ytterbium(II), and Europium(II) Complexes with Pyrrolidinyl‐ and Piperidinyl‐Functionalized Indenyl Ligands

Abstract

Abstract A series of organolanthanide complexes with pyrrolidinyl‐ and piperidinyl‐ functionalized indenyl ligands were synthesized by reaction of [(Me 3 Si) 2 N] 3 Ln III (μ‐Cl)Li(THF) 3 (Ln = Yb, Eu, Nd) with the corresponding indene compounds. Treatment of [(Me 3 Si) 2 N] 3 Yb III (μ‐Cl)Li(THF) 3 with 2 equiv. of C 9 H 6 ‐1‐R‐3‐CH 2 SiMe 2 NC 4 H 8 (R = H, CH 3 ) in refluxing toluene produced the corresponding organoytterbium(II) complexes with formula [η m :η 1 ‐C 9 H 5 ‐1‐R‐3‐CH 2 SiMe 2 NC 4 H 8 ] 2 Yb II [ m = 5, R = H ( 2 ); m = 3, R = CH 3 ( 3 )] in 49 and 58 % yield, respectively. Treatment of [(Me 3 Si) 2 N] 3 Ln III (μ‐Cl)Li(THF) 3 (Ln = Yb, Eu, Nd) with 2 equiv. of C 9 H 7 CH 2 SiMe 2 NC 5 H 10 ( 1 ) in toluene at moderately high temperatures afforded, after workup, the corresponding organolanthanide complexes with formula [η 5 :η 1 ‐C 9 H 6 CH 2 SiMe 2 NC 5 H 10 ] 2 Yb II ( 4 ), [η 5 :η 1 ‐C 9 H 6 CH 2 SiMe 2 NC 5 H 10 ] 2 Eu II ( 5 ), and [C 9 H 6 CH 2 SiMe 2 NC 5 H 10 ] 3 Nd III · THF ( 6 ) in 37, 71, and 29 % yield, respectively. All the compounds were fully characterized by spectroscopic methods and elemental analyses. The structures of complexes 2 , 3 , 5 , and 6 were additionally determined by single‐crystal X‐ray analyses. The catalytic properties of all the organolanthanide complexes on the ring‐opening polymerization of ϵ‐caprolactone have been studied. The effects of temperature, solvent, and coordination on the catalytic activities of the complexes were examined. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)