Synthesis and Characterization of Homoleptic Lanthanide Guanidinate Complexes and Their Catalytic Activity for the Ring‐Opening Polymerization of Trimethylene Carbonate

Abstract

Abstract Two methods to synthesize homoleptic guanidinate lanthanide complex are described. The samarium guanidinate complex [Sm{Ph 2 NC(NCy) 2 } 3 ]·2C 7 H 8 ( 1 ) can be synthesized by the metathesis reaction of lithium guanidinate with anhydrous samarium trichloride in a 3:1 molar ratio. The analogous complexes [Ln{Ph 2 NC(NCy) 2 } 3 ]·2C 7 H 8 [Ln = Yb ( 2 ), Nd ( 3 )] can also be synthesized by the insertion reaction of N , N ′‐dicyclohexylcarbodiimide into the Ln−N bond of [(THF) 4 Li][Ln(NPh 2 ) 4 ] in a 3:1 molar ratio in good yield. Complexes 1 − 3 were characterized by elemental analysis, IR and 1 H NMR spectroscopy. The molecular structures of complexes 1 and 3 were further determined by X‐ray diffraction techniques. These complexes showed high activity for the ring‐opening polymerization of trimethylene carbonate (TMC), giving polymers with M w / M n ranging from 1.41−1.73. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)