Chinese Journal of Applied Chemistry ›› 2022, Vol. 39 ›› Issue (5): 843-851.DOI: 10.19894/j.issn.1000-0518.210482

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Synthesis, Characterization and Catalytic Activity of Benzylamine⁃bridged Bis(phenolato)lanthanide Complexes

Hong-Xia CHEN1,2,3, Bao-Xia LI1, Ying-Ming YAO1(), Peng LIU4   

  1. 1.College of Chemistry,Chemical Engineering and Materials Science,Soochow University,Suzhou 215123,China
    2.Jiangsu Canlon Building Materials Co. ,Ltd,Suzhou 215234,China
    3.Department of Laboratory and Equipment Management,Soochow University,Suzhou 215021,China
    4.Testing and Analysis Center,Soochow University,Suzhou 215123,China
  • Received:2021-09-28 Accepted:2022-01-04 Published:2022-05-01 Online:2022-05-24
  • Contact: Ying-Ming YAO
  • About author:yaoym@suda.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(21674070)

Abstract:

Lanthanide metal complexes stabilized by benzylamine-bridged bis(phenolato) ligand, (PhN{CH2-(2-O-C6H2-Bu2t-3,5)}2) (L1), were synthesized by the reaction of the ligand precursor L1H2 with lanthanide amide. The reaction media has profound influence on the reaction. The reaction of Ln[N(SiMe323μ-Cl)Li(THF)3 with L1H2 in a 1∶1 molar ratio is performed in toluene at 90 ℃ to give the desired benzylamine-bridged bis(phenolate) lanthanide amido complexes L1LnN(SiMe32(THF) (Ln = Yb (1), Sm (2)), while the same reaction of Sm[N(SiMe323μ-Cl)Li(THF)3 with L1H2 in a 1∶1 molar ratio in THF at 50 ℃ only gives the unexpected Sm-Li heterobimetallic complex (THF)LiL12Sm (3). All of these complexes were characterized by IR, elemental analysis and single crystal X-ray diffraction. The catalytic activities of complexes 1 and 2 for the ring-opening polymerization of L-lactide and DL-lactide were tested. It is found that these complexes are efficient initiators for lactide polymerization to give polylactide with high relative molecular mass. Complex 1 has good stereoselectivity for DL-lactide polymerization to give syndio-rich polylactide (Pr=0.87).

Key words: Benzylamine-bridged bis(phenolato) ligand, Lanthanide complex, Lactide, Polymerization

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