Ring-opening polymerization of ε-caprolactone has been carried out by using rare earth Schiff base complexes： lanthanide tris（N-phenyl-3,5-di-t-butylsalicylaldiminato）s [Ln（OPBS）3] as single component catalyst f...Ring-opening polymerization of ε-caprolactone has been carried out by using rare earth Schiff base complexes： lanthanide tris（N-phenyl-3,5-di-t-butylsalicylaldiminato）s [Ln（OPBS）3] as single component catalyst for the first time. The influences of different rare earth elements, monomer and catalyst concentration as well as reaction time on the polymerization were investigated. Mechanism studies showed that monomer inserts into the active site with the acyl-oxygen bond scission rather than the break of alkyl-oxygen bond.展开更多
Lanthanum complex supported by the heterocyclic Schiff-base ligand of N-(2-pyridyl)-3,5-di-tert-butyl-salicylaldimine was prepared and employed for the ring-opening polymerization(ROP)ofε-caprolactone(ε-CL).The poly...Lanthanum complex supported by the heterocyclic Schiff-base ligand of N-(2-pyridyl)-3,5-di-tert-butyl-salicylaldimine was prepared and employed for the ring-opening polymerization(ROP)ofε-caprolactone(ε-CL).The polymers obtained with this initiator showed a unimodal molecular weight distribution implied that only one active species was present.Mechanism study revealed that the polymerization proceeds via acyl-oxygen bond cleavage.展开更多
Anhydrous LnCl 3 reacts with 2 equiv. of the sodium salt of the bidentate Schiff base N (2,6 diisopropylphenyl)salicylaldimine in THF to form the monomeric lanthanide chlorides [2 OC 6H 4CH= N(2,6 i P...Anhydrous LnCl 3 reacts with 2 equiv. of the sodium salt of the bidentate Schiff base N (2,6 diisopropylphenyl)salicylaldimine in THF to form the monomeric lanthanide chlorides [2 OC 6H 4CH= N(2,6 i Pr 2C 6H 3) ] 2LnCl(THF) [Ln=Yb (1), Er (2)]. Complex 1 crystallizes in P 1 space group with a =0 9215(2) nm, b = 1 36612(4) nm, c =1 6899(2) nm, α =74 83(3)°, β = 77 43(2)°, γ =81 04(1)°, Z =2, V =1 9929(4) nm 3, D c=1 402 g/cm 3. The two complexes exhibited fairly good catalytic activity in the ring opening polymerization of ε caprolactone.展开更多
The divalent Sm complex supported by Schiff base ligand [2 OC 6H 4CH [ZJLX,Y] N(2,6 i Pr 2 C 6H 3)] 2Sm(THF) 2 has been prepared by the reaction of 2Sm(THF) 2 has been prepared by the reaction of [2 OC 6H 4CH [ZJLX,Y]...The divalent Sm complex supported by Schiff base ligand [2 OC 6H 4CH [ZJLX,Y] N(2,6 i Pr 2 C 6H 3)] 2Sm(THF) 2 has been prepared by the reaction of 2Sm(THF) 2 has been prepared by the reaction of [2 OC 6H 4CH [ZJLX,Y] N(2,6 i Pr 2C 6H 3)]Na Na with SmI 2 in THF. It exhibits a good catalytic activity for the polymerization of ε caprolactone, and the polymer obtained has a narrow molecular weight distribution.展开更多
Divalent β-diketiminate lanthanide complexes LYbR（THF）（L=｛（2,6-Me2C6H3）NC（Me）｝2CH;R=C9H7（1）,CH3C5H4（2）,OC6H2-But2-2,6-Me-4（32））were synthesized by reducing the mixed-ligand trivalen（t） β-diketimina...Divalent β-diketiminate lanthanide complexes LYbR（THF）（L=｛（2,6-Me2C6H3）NC（Me）｝2CH;R=C9H7（1）,CH3C5H4（2）,OC6H2-But2-2,6-Me-4（32））were synthesized by reducing the mixed-ligand trivalen（t） β-diketiminate ytterbium chlorides synthesized in situ with Na-K alloy.These divalent lanthanide complexes exhibit good catalytic activity for the ring opening polymerization of ε-caprolactone.展开更多
基金This work was financially supported by the Key Program of National Natural Science Foundation of China(No.G 20434020)the Special Funds for Major Basic Research Projects(No.G 2005 CB623802)the Committee of Science and Technology of Zhejiang Province.
文摘Ring-opening polymerization of ε-caprolactone has been carried out by using rare earth Schiff base complexes： lanthanide tris（N-phenyl-3,5-di-t-butylsalicylaldiminato）s [Ln（OPBS）3] as single component catalyst for the first time. The influences of different rare earth elements, monomer and catalyst concentration as well as reaction time on the polymerization were investigated. Mechanism studies showed that monomer inserts into the active site with the acyl-oxygen bond scission rather than the break of alkyl-oxygen bond.
文摘Lanthanum complex supported by the heterocyclic Schiff-base ligand of N-(2-pyridyl)-3,5-di-tert-butyl-salicylaldimine was prepared and employed for the ring-opening polymerization(ROP)ofε-caprolactone(ε-CL).The polymers obtained with this initiator showed a unimodal molecular weight distribution implied that only one active species was present.Mechanism study revealed that the polymerization proceeds via acyl-oxygen bond cleavage.
基金theNationalNaturalScienceFoundationofChina (No .2 0 0 72 0 2 7)
文摘Anhydrous LnCl 3 reacts with 2 equiv. of the sodium salt of the bidentate Schiff base N (2,6 diisopropylphenyl)salicylaldimine in THF to form the monomeric lanthanide chlorides [2 OC 6H 4CH= N(2,6 i Pr 2C 6H 3) ] 2LnCl(THF) [Ln=Yb (1), Er (2)]. Complex 1 crystallizes in P 1 space group with a =0 9215(2) nm, b = 1 36612(4) nm, c =1 6899(2) nm, α =74 83(3)°, β = 77 43(2)°, γ =81 04(1)°, Z =2, V =1 9929(4) nm 3, D c=1 402 g/cm 3. The two complexes exhibited fairly good catalytic activity in the ring opening polymerization of ε caprolactone.
文摘The divalent Sm complex supported by Schiff base ligand [2 OC 6H 4CH [ZJLX,Y] N(2,6 i Pr 2 C 6H 3)] 2Sm(THF) 2 has been prepared by the reaction of 2Sm(THF) 2 has been prepared by the reaction of [2 OC 6H 4CH [ZJLX,Y] N(2,6 i Pr 2C 6H 3)]Na Na with SmI 2 in THF. It exhibits a good catalytic activity for the polymerization of ε caprolactone, and the polymer obtained has a narrow molecular weight distribution.
基金Supported by the National Natural Science Foundation of China (20774078)the Special Funds for National Basic Research Program of China (973 Program,G2005CB623802)the Scientific Research Foundation for Returned Scholars,Ministry of Education of China
文摘Divalent β-diketiminate lanthanide complexes LYbR（THF）（L=｛（2,6-Me2C6H3）NC（Me）｝2CH;R=C9H7（1）,CH3C5H4（2）,OC6H2-But2-2,6-Me-4（32））were synthesized by reducing the mixed-ligand trivalen（t） β-diketiminate ytterbium chlorides synthesized in situ with Na-K alloy.These divalent lanthanide complexes exhibit good catalytic activity for the ring opening polymerization of ε-caprolactone.
