Polyesters,as a class of high-performance and versatile polymer materials,often suffer from some drawbacks,such as hydrophobicity and brittleness due to their single structure nature.Thus,modifications have attracted ...Polyesters,as a class of high-performance and versatile polymer materials,often suffer from some drawbacks,such as hydrophobicity and brittleness due to their single structure nature.Thus,modifications have attracted much attention for enhancing their desirable properties,of which one efficient way is incorporating the aliphatic polyether segment into the main chain of the polyester.However,this approach is of much challenge because the obtained polyesters are problematic in either low alternating degree or low molecular weight.Herein,we describe an efficient strategy to incorporate polyether fragment into polyester by developing a novel Co-Al based heterodinuclear complex for mediating the copolymerization of propylene oxide(PO)withε-caprolactone(CL).The tracking experiments reveal that PO and CL convert into the polymer chain throughout the polymerization process.Especially,the linear increase in the molecular weight with conversion of CL indicates the controllable nature of the copolymerization.The competition polymerization,offering the monomer reactivity ratios of rCL=0.96 and rPO=1.04,suggests that the tendency of self-propagation or incorporation of monomers is nearly identical.interestingly,the obtained polymers with different ether contents exhibit tunable thermal properties with enhanced decomposition temperature for the polymer with higher ether content.The newly developed heterodinuclear complex for new polymerization provides an idea to synthesize new functional polymeric materials.展开更多
Some reactions of R3SnM（CO）5 （M = Mn, Re） with CH3CN or pyridine were investigated to give complexes R3SnMn（CO）3LL＇ or R3SnMn（CO）4L by a facile mild method. X-ray diffractions analyses show that, in contrast ...Some reactions of R3SnM（CO）5 （M = Mn, Re） with CH3CN or pyridine were investigated to give complexes R3SnMn（CO）3LL＇ or R3SnMn（CO）4L by a facile mild method. X-ray diffractions analyses show that, in contrast to the phosphine ligand occupying in axial position, nitrogen ligands occupy equatorial position.展开更多
A new dinucleating ligand consisting of a tetraphenylporphyrin derivative covalently linked with tris(2-benzimidazylmethyl)-amine and its homodinuclear Co-Co and heterodinuclear Co-Cu complexes were synthesized and ...A new dinucleating ligand consisting of a tetraphenylporphyrin derivative covalently linked with tris(2-benzimidazylmethyl)-amine and its homodinuclear Co-Co and heterodinuclear Co-Cu complexes were synthesized and spectroscopically characterized. The heterobimetallic cobalt-copper complex bearing three benzimidazole ligands for copper, as cytochrome c oxidase active site model, was applied to the surface of glassy carbon electrode to show electrocatalytic activity for O 2 reduction in aqueous solution at an acidity level close to physiological pH value. The kinetic parameters of this electrocatalytic process were obtained.展开更多
Two d-f heterodinuclear cryptates Eu(Ⅲ)-M(Ⅱ)(M=Zn 2+, Ni 2+) were synthesized and characterized by elemental analysis, IR and ES-MS. The fluorescence properties of the cyptates in acetonitrile solution show that inc...Two d-f heterodinuclear cryptates Eu(Ⅲ)-M(Ⅱ)(M=Zn 2+, Ni 2+) were synthesized and characterized by elemental analysis, IR and ES-MS. The fluorescence properties of the cyptates in acetonitrile solution show that inclusion of Zn 2+ in the mononuclear europium(Ⅲ) cryptate increases the energy transfer between cryptand and europium(Ⅲ) ion, while the inclusion of Ni 2+ in the cavity quenches the fluorescence of Eu(Ⅲ) cryptate.展开更多
The mononuclear cryptate [Eu(H 3L F)(NO 3)(H 2O)](NO 3) 2 and the heterodinuclear cryptate [EuZnL F(DMF)](ClO 4) 2 were synthesized and characterized. The triplet state energy of the cryptand (H 3L F) was ...The mononuclear cryptate [Eu(H 3L F)(NO 3)(H 2O)](NO 3) 2 and the heterodinuclear cryptate [EuZnL F(DMF)](ClO 4) 2 were synthesized and characterized. The triplet state energy of the cryptand (H 3L F) was studied by phosphorescence spectrum. The fluorescent properties of Eu(Ⅲ) cryptates in MeOH solution show that the cryptand (H 3L F) can sensitize the Eu(Ⅲ) ion to luminescence and the introduction of the Zn(Ⅱ) ion into the mononuclear Eu(Ⅲ) cryptate resulted in blue shift of three ligand centered bands, increase of molar absorption coefficient and increase of the luminescence intensity of Eu(Ⅲ).展开更多
The direct conversion of carbon dioxide(CO_(2))and propylene oxide(PO)into propylene carbonate(PC)offers a green way to utilize anthropogenic CO_(2).However,this reaction is limited by low conversion of PO and harsh r...The direct conversion of carbon dioxide(CO_(2))and propylene oxide(PO)into propylene carbonate(PC)offers a green way to utilize anthropogenic CO_(2).However,this reaction is limited by low conversion of PO and harsh reaction conditions.In this study,we solve this problem using ionic liquids(ILs)/metal oxide composites(ILs@MAO).The catalytic activity of MAO-500(500?annealing temperature)is poor evidenced by its low conversion of PO(24.94%).However,ILs@MAO-500 has a high conversion of PO(97.54%)under similar reaction conditions(2 h at 1.5 MPa CO_(2) pressure,90℃,and 0.85 g catalyst).The ILs consist of imidazolium cation with weak coordinated[NTf_(2)]^(-)anion leading to outward movement of anion resulting in the formation of“heterodinuclear complex”.This complex generates an amorphous-crystalline intermediate with balanced acidbase sites that activate PO and stabilize the catalytic intermediate.In large part,the high PO conversion is theorized to be primarily due to the abundant reactive sites in the ILs that are covalently immobilized on the MAO-500 carrier.Furthermore,even after multiple recycling,ILs@MAO-500 remains stable and exhibits high yield and selectivity.The proposed solvent-free catalytic system is mild,kinetically fast,and naturally safe for coupling CO_(2) and PO into PC synthesis.展开更多
基金the National Natural Science Foundation of China(Nos.21722402 and 21674015)the Fundamental Research Funds for the Central Universities(No.DUT18ZD105).
文摘Polyesters,as a class of high-performance and versatile polymer materials,often suffer from some drawbacks,such as hydrophobicity and brittleness due to their single structure nature.Thus,modifications have attracted much attention for enhancing their desirable properties,of which one efficient way is incorporating the aliphatic polyether segment into the main chain of the polyester.However,this approach is of much challenge because the obtained polyesters are problematic in either low alternating degree or low molecular weight.Herein,we describe an efficient strategy to incorporate polyether fragment into polyester by developing a novel Co-Al based heterodinuclear complex for mediating the copolymerization of propylene oxide(PO)withε-caprolactone(CL).The tracking experiments reveal that PO and CL convert into the polymer chain throughout the polymerization process.Especially,the linear increase in the molecular weight with conversion of CL indicates the controllable nature of the copolymerization.The competition polymerization,offering the monomer reactivity ratios of rCL=0.96 and rPO=1.04,suggests that the tendency of self-propagation or incorporation of monomers is nearly identical.interestingly,the obtained polymers with different ether contents exhibit tunable thermal properties with enhanced decomposition temperature for the polymer with higher ether content.The newly developed heterodinuclear complex for new polymerization provides an idea to synthesize new functional polymeric materials.
基金supported by the National Natural Science Foundation of China(No.29672018).
文摘Some reactions of R3SnM（CO）5 （M = Mn, Re） with CH3CN or pyridine were investigated to give complexes R3SnMn（CO）3LL＇ or R3SnMn（CO）4L by a facile mild method. X-ray diffractions analyses show that, in contrast to the phosphine ligand occupying in axial position, nitrogen ligands occupy equatorial position.
文摘A new dinucleating ligand consisting of a tetraphenylporphyrin derivative covalently linked with tris(2-benzimidazylmethyl)-amine and its homodinuclear Co-Co and heterodinuclear Co-Cu complexes were synthesized and spectroscopically characterized. The heterobimetallic cobalt-copper complex bearing three benzimidazole ligands for copper, as cytochrome c oxidase active site model, was applied to the surface of glassy carbon electrode to show electrocatalytic activity for O 2 reduction in aqueous solution at an acidity level close to physiological pH value. The kinetic parameters of this electrocatalytic process were obtained.
文摘Two d-f heterodinuclear cryptates Eu(Ⅲ)-M(Ⅱ)(M=Zn 2+, Ni 2+) were synthesized and characterized by elemental analysis, IR and ES-MS. The fluorescence properties of the cyptates in acetonitrile solution show that inclusion of Zn 2+ in the mononuclear europium(Ⅲ) cryptate increases the energy transfer between cryptand and europium(Ⅲ) ion, while the inclusion of Ni 2+ in the cavity quenches the fluorescence of Eu(Ⅲ) cryptate.
文摘The mononuclear cryptate [Eu(H 3L F)(NO 3)(H 2O)](NO 3) 2 and the heterodinuclear cryptate [EuZnL F(DMF)](ClO 4) 2 were synthesized and characterized. The triplet state energy of the cryptand (H 3L F) was studied by phosphorescence spectrum. The fluorescent properties of Eu(Ⅲ) cryptates in MeOH solution show that the cryptand (H 3L F) can sensitize the Eu(Ⅲ) ion to luminescence and the introduction of the Zn(Ⅱ) ion into the mononuclear Eu(Ⅲ) cryptate resulted in blue shift of three ligand centered bands, increase of molar absorption coefficient and increase of the luminescence intensity of Eu(Ⅲ).
基金supported by the National Research Foundation(NRF)grants funded by the Ministry of Education(2020R1A6A1A03038817),Republic of Korea.
文摘The direct conversion of carbon dioxide(CO_(2))and propylene oxide(PO)into propylene carbonate(PC)offers a green way to utilize anthropogenic CO_(2).However,this reaction is limited by low conversion of PO and harsh reaction conditions.In this study,we solve this problem using ionic liquids(ILs)/metal oxide composites(ILs@MAO).The catalytic activity of MAO-500(500?annealing temperature)is poor evidenced by its low conversion of PO(24.94%).However,ILs@MAO-500 has a high conversion of PO(97.54%)under similar reaction conditions(2 h at 1.5 MPa CO_(2) pressure,90℃,and 0.85 g catalyst).The ILs consist of imidazolium cation with weak coordinated[NTf_(2)]^(-)anion leading to outward movement of anion resulting in the formation of“heterodinuclear complex”.This complex generates an amorphous-crystalline intermediate with balanced acidbase sites that activate PO and stabilize the catalytic intermediate.In large part,the high PO conversion is theorized to be primarily due to the abundant reactive sites in the ILs that are covalently immobilized on the MAO-500 carrier.Furthermore,even after multiple recycling,ILs@MAO-500 remains stable and exhibits high yield and selectivity.The proposed solvent-free catalytic system is mild,kinetically fast,and naturally safe for coupling CO_(2) and PO into PC synthesis.
