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Synthesis and Characterization of Lanthanide( III ) Bis(guanidinate) Derivatives and the Catalytic Activity of Methyllanthanide Bis(guanidinate) Complexes for the Polymerization of ϵ‐Caprolactone and Methyl Methacrylate
Author(s) -
Luo Yunjie,
Yao Yingming,
Shen Qi,
Yu Kaibei,
Weng Linhong
Publication year - 2003
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200390043
Subject(s) - chemistry , lanthanide , polymerization , caprolactone , ligand (biochemistry) , octahedral molecular geometry , catalysis , crystal structure , polymer chemistry , medicinal chemistry , octahedron , crystallography , stereochemistry , polymer , organic chemistry , ion , biochemistry , receptor
The synthesis and structure of new lanthanide complexes with the guanidinate ligand [(Me 3 Si) 2 NC(N i Pr) 2 − ] are described. Reaction of a THF slurry of LnCl 3 with a hexane solution of [(SiMe 3 ) 2 NC(N i Pr) 2 ]Li ( 1 ) in a 1:2 molar ratio afforded the new soluble organolanthanide complexes [(SiMe 3 ) 2 NC(N i Pr) 2 ]Ln(μ‐Cl) 2 Li(THF) 2 [Ln = Yb ( 2 ), Nd ( 3 )]. Alkylation of 2 and 3 with 2 equiv. of MeLi in hexane gave [(SiMe 3 ) 2 NC(N i Pr) 2 ]Ln(μ‐Me) 2 Li(TMEDA) [Ln = Yb ( 4 ), Nd ( 5 )] in good yield as crystalline solids. The molecular structures of 2 and 5 were determined by single‐crystal X‐ray analysis. The lanthanide ions in these complexes display a distorted pseudo‐octahedral coordination geometry. Complexes 4 and 5 exhibited extremely high activity for the ring‐opening polymerization of ϵ‐caprolactone to give high molecular weight polymers. Complex 5 also showed good catalytic activity for the syndiotactic polymerization of methyl methacrylate. (© Wiley‐VCH Verlag GmbH & Co KGaA, 69451 Weinheim, Germany, 2002)