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
A series of anilido-imine zinc complexes ortho-C6H4（CH：NAr）（NAr）ZnEt[Ar=2,6-Me2C6H3（2a）; Ar=2,6-Et2C6H3（2b）] was synthesized, characterized and used as catalysts for the ring-opening polymerization of L-lacti...A series of anilido-imine zinc complexes ortho-C6H4（CH：NAr）（NAr）ZnEt[Ar=2,6-Me2C6H3（2a）; Ar=2,6-Et2C6H3（2b）] was synthesized, characterized and used as catalysts for the ring-opening polymerization of L-lactide in the presence of benzyl alcohol. The effects of the structures of catalysts and reaction conditions on the reactivity were investigated. The polymerization of L-lactide initiated by each of these complexes was found to take place with a controlled manner.展开更多
The reaction between K(1 C 5H 9C 9H 6) and anhydrous LnCl 3 (Ln=Sm, Yb) in the molar ratio of 2∶1 in THF with subsequent treatment by Na K alloy afforded (1 C 5H 9C 9H 6) 2Ln (THF) n (Ln=Sm, n =...The reaction between K(1 C 5H 9C 9H 6) and anhydrous LnCl 3 (Ln=Sm, Yb) in the molar ratio of 2∶1 in THF with subsequent treatment by Na K alloy afforded (1 C 5H 9C 9H 6) 2Ln (THF) n (Ln=Sm, n =1; Ln=Yb, n =2), while the reaction of SmI 2 with K(1 C 5H 9C 9H 6) in the molar ratio of 1∶2 in THF gave the anionic complex K(1 C 5H 9C 9H 6) 3Sm(THF) 3. The X ray structure of (1 C 5H 9C 9H 6) 2Yb(THF) 2 showed that central metal Yb is coordinated by two cyclopentadienyl rings of 1 cyclopentylindenyls and two oxygen atoms from two tetrahydrofuran molecules to form pseudo tetrahedral coordinate geometry. All these complexes are active for the polymerization of acrylonitrile.展开更多
Ring-opening polymerization of D,L-lactide has been successfully carried out by(ArO)2Sm (THF)4 (ArO = 2, 6-ditertbutyl(4-methylphenoxo-) as catalyst for the first time.The catalyst contentration, monomer concentration...Ring-opening polymerization of D,L-lactide has been successfully carried out by(ArO)2Sm (THF)4 (ArO = 2, 6-ditertbutyl(4-methylphenoxo-) as catalyst for the first time.The catalyst contentration, monomer concentration and solvent showed a marked effect onthe polymerization. The polymerization rate decrease with increase of monomer concentra-tion and decrease of catalyst concentration. The initiation mechanism has been discussed ac-cording to the results of end-group analysis of oligomer by IR. The active species are sup-posed to be a samarium enolate formed from the reaction of (ArO)2Sm(THF)4 with lactide.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.
基金Supported by the National Natural Science Foundation of China（No.21104026）.
文摘A series of anilido-imine zinc complexes ortho-C6H4（CH：NAr）（NAr）ZnEt[Ar=2,6-Me2C6H3（2a）; Ar=2,6-Et2C6H3（2b）] was synthesized, characterized and used as catalysts for the ring-opening polymerization of L-lactide in the presence of benzyl alcohol. The effects of the structures of catalysts and reaction conditions on the reactivity were investigated. The polymerization of L-lactide initiated by each of these complexes was found to take place with a controlled manner.
文摘The reaction between K(1 C 5H 9C 9H 6) and anhydrous LnCl 3 (Ln=Sm, Yb) in the molar ratio of 2∶1 in THF with subsequent treatment by Na K alloy afforded (1 C 5H 9C 9H 6) 2Ln (THF) n (Ln=Sm, n =1; Ln=Yb, n =2), while the reaction of SmI 2 with K(1 C 5H 9C 9H 6) in the molar ratio of 1∶2 in THF gave the anionic complex K(1 C 5H 9C 9H 6) 3Sm(THF) 3. The X ray structure of (1 C 5H 9C 9H 6) 2Yb(THF) 2 showed that central metal Yb is coordinated by two cyclopentadienyl rings of 1 cyclopentylindenyls and two oxygen atoms from two tetrahydrofuran molecules to form pseudo tetrahedral coordinate geometry. All these complexes are active for the polymerization of acrylonitrile.
文摘Ring-opening polymerization of D,L-lactide has been successfully carried out by(ArO)2Sm (THF)4 (ArO = 2, 6-ditertbutyl(4-methylphenoxo-) as catalyst for the first time.The catalyst contentration, monomer concentration and solvent showed a marked effect onthe polymerization. The polymerization rate decrease with increase of monomer concentra-tion and decrease of catalyst concentration. The initiation mechanism has been discussed ac-cording to the results of end-group analysis of oligomer by IR. The active species are sup-posed to be a samarium enolate formed from the reaction of (ArO)2Sm(THF)4 with lactide.
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.
