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
Reaction of the β diketimine compound (2,6 Me 2C 6H 3)NC(Me)CHC(Me)N(C 6H 3 2,6 Me 2)H (LH,1) with 1 equiv of n BuLi/hexane in THF,followed by crystallization from toluene,affords the β diketiminate lithium complex ...Reaction of the β diketimine compound (2,6 Me 2C 6H 3)NC(Me)CHC(Me)N(C 6H 3 2,6 Me 2)H (LH,1) with 1 equiv of n BuLi/hexane in THF,followed by crystallization from toluene,affords the β diketiminate lithium complex LLi(THF)(2)in high yields.The crystal structure of complex 2 was determined by X ray diffraction method.It crystallizes in monoclinic,space group P 2/(1)/ n with a =1 4036(5), b =1 3261(4), c =1 4248(5)nm, β =115 437(6)°, V =2 3950(13)nm 3,and D c =1 066Mg·m -3 for Z =4.In the structure,the metallacycle is almost fully planar,and the Li atom is coordinated by two nitrogen atoms of the β diketiminate ligand and one oxygen atom of THF molecule.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
The catalytic activity of complex [(Bu t C 5H 4) 2NdMe] 2(1) for MMA polymerization has been investigated. It was found that (1) shows high catalytic activity at -78 ℃, however, the catalytic activity decreases with ...The catalytic activity of complex [(Bu t C 5H 4) 2NdMe] 2(1) for MMA polymerization has been investigated. It was found that (1) shows high catalytic activity at -78 ℃, however, the catalytic activity decreases with the increase of polymerization temperature dramatically. The conversion is as high as 100% at -40 ℃ in the case of n (catalyst)∶ n (monomer)=3∶1000, while the conversion is 0 at 40 ℃. The stoichiometric reaction between (1) and MMA in 1∶2 mole ratio at 40 ℃ gave complex [(Bu t C 5H 4) 2NdOMe] 2(2), which was formed by the nucleophilic substitution reaction of (1) to ester group of MMA. The result is explained in terms of deactivation of (1) for MMA polymerization above room temperature. The structure of (2) was confirmed by elemental analysis, IR, MS and X ray diffraction measurements.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
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Reaction of the β diketimine compound (2,6 Me 2C 6H 3)NC(Me)CHC(Me)N(C 6H 3 2,6 Me 2)H (LH,1) with 1 equiv of n BuLi/hexane in THF,followed by crystallization from toluene,affords the β diketiminate lithium complex LLi(THF)(2)in high yields.The crystal structure of complex 2 was determined by X ray diffraction method.It crystallizes in monoclinic,space group P 2/(1)/ n with a =1 4036(5), b =1 3261(4), c =1 4248(5)nm, β =115 437(6)°, V =2 3950(13)nm 3,and D c =1 066Mg·m -3 for Z =4.In the structure,the metallacycle is almost fully planar,and the Li atom is coordinated by two nitrogen atoms of the β diketiminate ligand and one oxygen atom of THF molecule.
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.
文摘The catalytic activity of complex [(Bu t C 5H 4) 2NdMe] 2(1) for MMA polymerization has been investigated. It was found that (1) shows high catalytic activity at -78 ℃, however, the catalytic activity decreases with the increase of polymerization temperature dramatically. The conversion is as high as 100% at -40 ℃ in the case of n (catalyst)∶ n (monomer)=3∶1000, while the conversion is 0 at 40 ℃. The stoichiometric reaction between (1) and MMA in 1∶2 mole ratio at 40 ℃ gave complex [(Bu t C 5H 4) 2NdOMe] 2(2), which was formed by the nucleophilic substitution reaction of (1) to ester group of MMA. The result is explained in terms of deactivation of (1) for MMA polymerization above room temperature. The structure of (2) was confirmed by elemental analysis, IR, MS and X ray diffraction measurements.
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.
