Syntheses And Structures Of Lanthanide Complexes Supported By β-Diketiminato Ligand Systems And Their Catalytic Activity For The Polymerization Of ε-caprolactone

Thirteen organolanthanide complexes supported by P-diketiminato ligand were first synthesized. The crystal structures of nine compounds were determined by X- r-ay analysis.Their catalytic activities for polymerization of e-caprolactone were investigated respectively.1.Reaction of anhydrous YbCl3 with [(DIPPh)2nacnac]Li((DIPPh)2nacnac =N, N-diisopropylphenyl-2,4-pentanediimine anion) in 1:1 molar ratio in THF-toluene mixed solvent, followed by crystallization from THF, affords the monomeric complex [(DIPPh)2 nacnac]YbCla(THF)2 (1). Recrystallization of complex 1 from toluene gives {[(DIPPh)2nacnac]YbCl(/i-Cl)3Yb[(DIPPh)2nacnac](THF)}-l/2MePh (2). All these compounds were characterized by elemental analysis and IR spectrum. The X-ray analysis of complex 2 indicates that there is a rare triple chloride bridge in the molecule.2.Reaction of complex 1 with Cp'Na(Cp'= C5H5, CH3C5H4, Bu'C5H4) in 1:1 molar ratio in THF-toluene mixed solvent gives the mixed-ligand ytterbium chloride Cp'[(DIPPh)2nacnac]YbCl (Cp'=C5H5 (3), CH3C5H4 (4), t-BuC5H4(5)). All these compounds were characterized by elemental analysis and IR spectrum. The complex 4 has been characterized by an X-ray diffraction structure determination. Molecular structure determination of complex 4 shows that the central metal is six-coordinated 03.Reaction of complex 1 with Ind'M (M=K,Ind'=C9H7, C5H9C9H6) or ArONa (ArO=2,6-But2-4-MeC6H2O) in 1:1 molar ratio in THF-toluene mixed solvent gives the mixed-ligand ytterbium chloride Ind'[(DIPPh)2nacnac]YbCl (Ind'= C9H7(6), C5H9C9H6 (7)) and ArO[(DIPPh)2nacnac]YbCl(THF) (8) respectively. All these compounds were characterized by elemental analysis and IR spectrum. The complexes 6 and 8 have been characterized by X-ray diffraction structuredetermination. Molecular structure determinations of complexes 6 and 8 show that the central metal is six-coordinated and five-coordinated in complex 6 and 8 respectively.4.Reaction of complex 4 with LiNCsHioor LiNPh2 in 1:1 molar ratio in toluene gave the following mixed-ligand ytterbium amides: (CH3CsH4)[(DIPPh)2nacnac]Yb NC5Hio(9) and (CH3C5H4)[(DIPPh)2nacnac]YbNPh2 (10). The compounds were characterized by elemental analysis and IR spectrum and an X-ray diffraction structure determination .5. Reaction of complexes 4,6,8 with Na-K alloy in 1:1 molar ratio in THF-toluene mixed solvent gave the following divalent orgaolanthanide complexes (CH3C5H4)[(DIPPh)2nacnac]Yb(THF) (11), (C9H7)[(DIPPh)2nacnac]Yb(THF) (12) and {(ArO)[(DIPPh)2nacnac]Yb(THF)}-THF (13). All these compounds were characterized by elemental analysis and IR spectrum and an X-ray diffraction structure determination .6.It was found that (ArO)[(DIPPh)2nacnac]YbCl(THF) (8) exhibits good catalytic activity in the ring-opening polymerization of e-caprolactone.