An unsymmetric 2,6-bis(imino)pyridine iron(II) complex 1' was synthesized. The relationship between catalyststructure and its activity in ethylene polymerization is discussed. The kinetic behavior of ethylene poly...An unsymmetric 2,6-bis(imino)pyridine iron(II) complex 1' was synthesized. The relationship between catalyststructure and its activity in ethylene polymerization is discussed. The kinetic behavior of ethylene polymerization and theeffects of polymerization conditions such as temperature, aluminum/iron molar ratio on the activity of catalyst and thecharacteristics of polyethylene were reported. The unsymmetric catalyst 1' has a good catalytic performance of 3.47×10~6 gPE·mol^(-1)·Fe·h^(-1) at 40℃ with aluminum/iron molar ratio = 2500. A dependence of catalyst activity on themethylaluminoxane (MAO) concentration and reaction temperature was found. The molecular weight (MW) of polyethylenewith broad dispersity is about 10~4-10~5 g/mol. The melting temperature and branching of polyethylenes vary with changingreaction temperature and aluminum/iron molar ratio.展开更多
The unsymmetric precursor ethyl 6-acetylpyridine-2-carboxylate （4） was synthesized from 2,6-dimethylpyridine （1）. On the basis of this precursor, a new mono（imino）pyridine ligand （5） and the corresponding Co...The unsymmetric precursor ethyl 6-acetylpyridine-2-carboxylate （4） was synthesized from 2,6-dimethylpyridine （1）. On the basis of this precursor, a new mono（imino）pyridine ligand （5） and the corresponding Co（Ⅱ） complex {2-carbethoxy-6-[1-[（2,6-diethylphenyl）imino]ethyl]pyridine}CoCl2 （6） were prepared. The crystal structure of complex indicates that the 2-carbethoxy-6-iminopyridine is coordinated to the cobalt as a tridentate ligand using [N, N, O] atoms, and the coordination geometry of the central cobalt is a distorted trigonal bipyramid, with the pyridyl nitrogen atom and the two chlorine atoms forming the equatorial plane. Being applied to the ethylene oligomedzation, this cobalt complex shows catalytic activity of 1.820× 10^4 g/mol-Cooh at 101325 Pa of ethylene at 15.5℃ for 1 h, when 1000 equiv, of methylaluminoxane （MAO） is employed as the cocatalyst.展开更多
In order to study the influence of substituents on imino-aryl rings of mono(imino)pyrrole-transition metal complexes to their ethylene polymerization performance,a series of mono(imine)pyrroles(L1-L3)were synthesized ...In order to study the influence of substituents on imino-aryl rings of mono(imino)pyrrole-transition metal complexes to their ethylene polymerization performance,a series of mono(imine)pyrroles(L1-L3)were synthesized by microwave irradiation from 2-acetylpyrrole and a series of 2,6-position disubstituted anilines(substituent:H,Me,Et).A simplified synthetic method was introduced to prepare the corresponding nickel complexes NiL2(1~3)with direct condensation of mono(imine)pyrrole ligands and nickel dichloride.All the compounds were fully characterized by 1 H NMR,IR,EA,MS,and X-ray crystal diffraction.Ligand L3(C16H20N2,Mr=240.34)belongs to the triclinic system,space group P1,with a=7.9606(19),b=9.028(2),c=11.205(3)?,the final R=0.0606 and wR=0.1875.Complex 3(C32H38N4Ni,Mr=537.37)belongs to the monoclinic system,space group C2/c with a=19.811(3),b=11.262(2),c=26.004(4)?,the final R=0.0388 and wR=0.1020.The crystal structures indicated that all the NiⅡcomplexes have similar tetra-coordinated geometries,in which the ligand chelated to the center nickel with a 2:1 molar ratio.Catalytic properties of the NiⅡcomplexes for ethylene polymerization were systematically investigated,and the results showed a regular increase of catalytic activities with steric hindrance of the substituents on the imino-aryl ring of NiⅡcomplexes.展开更多
A series of new complexes {2,6-bis[1-((2-methyl-4-methoxyphenyl)imino)ethyl]pyri-dine}MCI2 [M=Fe(Ⅱ) (2), Co(Ⅱ) (3), Ni(Ⅱ) (4), Cu(Ⅱ) (5), Zn(Ⅱ) (6)] have been synthesized. At 25℃, using 500 equiv of methylalumin...A series of new complexes {2,6-bis[1-((2-methyl-4-methoxyphenyl)imino)ethyl]pyri-dine}MCI2 [M=Fe(Ⅱ) (2), Co(Ⅱ) (3), Ni(Ⅱ) (4), Cu(Ⅱ) (5), Zn(Ⅱ) (6)] have been synthesized. At 25℃, using 500 equiv of methylaluminoxane (MAO), the activities of Fe(Ⅱ), Co(Ⅱ) catalysts can reach 4.02×106 g/mol-Fehatm for ethylene polymerization and 3.98×105 g/mol-Cohatm for ethylene oligomerization. The effects of polymerization conditions such as reaction temperature, Al/M molar ratio and time on the activity of catalyst have been explored.展开更多
基金This work was financially supported by the National Natural Science Foundation of China (No. 29734141, 50103012) Core Research for Engineering Innovation KGCX2-203, the Foundation of "One Hundred Talents" program for W-H Sun, Chinese Academy of Sciences
文摘An unsymmetric 2,6-bis(imino)pyridine iron(II) complex 1' was synthesized. The relationship between catalyststructure and its activity in ethylene polymerization is discussed. The kinetic behavior of ethylene polymerization and theeffects of polymerization conditions such as temperature, aluminum/iron molar ratio on the activity of catalyst and thecharacteristics of polyethylene were reported. The unsymmetric catalyst 1' has a good catalytic performance of 3.47×10~6 gPE·mol^(-1)·Fe·h^(-1) at 40℃ with aluminum/iron molar ratio = 2500. A dependence of catalyst activity on themethylaluminoxane (MAO) concentration and reaction temperature was found. The molecular weight (MW) of polyethylenewith broad dispersity is about 10~4-10~5 g/mol. The melting temperature and branching of polyethylenes vary with changingreaction temperature and aluminum/iron molar ratio.
基金Project supported by the Program for Changjiang Scholars and Innovative Research Team in University, PCSIRT （No. IRT0559）, the National Natural Science Foundation of China （No. 20371039） and the Major State Basic Research Development Program （No. 2003CB214600）.
文摘The unsymmetric precursor ethyl 6-acetylpyridine-2-carboxylate （4） was synthesized from 2,6-dimethylpyridine （1）. On the basis of this precursor, a new mono（imino）pyridine ligand （5） and the corresponding Co（Ⅱ） complex {2-carbethoxy-6-[1-[（2,6-diethylphenyl）imino]ethyl]pyridine}CoCl2 （6） were prepared. The crystal structure of complex indicates that the 2-carbethoxy-6-iminopyridine is coordinated to the cobalt as a tridentate ligand using [N, N, O] atoms, and the coordination geometry of the central cobalt is a distorted trigonal bipyramid, with the pyridyl nitrogen atom and the two chlorine atoms forming the equatorial plane. Being applied to the ethylene oligomedzation, this cobalt complex shows catalytic activity of 1.820× 10^4 g/mol-Cooh at 101325 Pa of ethylene at 15.5℃ for 1 h, when 1000 equiv, of methylaluminoxane （MAO） is employed as the cocatalyst.
基金supported by the National Natural Science Foundation of China (No. 51674200)the Science and Technology Research Program of Shaanxi Province (2019JM-421,2018JM2035)。
文摘In order to study the influence of substituents on imino-aryl rings of mono(imino)pyrrole-transition metal complexes to their ethylene polymerization performance,a series of mono(imine)pyrroles(L1-L3)were synthesized by microwave irradiation from 2-acetylpyrrole and a series of 2,6-position disubstituted anilines(substituent:H,Me,Et).A simplified synthetic method was introduced to prepare the corresponding nickel complexes NiL2(1~3)with direct condensation of mono(imine)pyrrole ligands and nickel dichloride.All the compounds were fully characterized by 1 H NMR,IR,EA,MS,and X-ray crystal diffraction.Ligand L3(C16H20N2,Mr=240.34)belongs to the triclinic system,space group P1,with a=7.9606(19),b=9.028(2),c=11.205(3)?,the final R=0.0606 and wR=0.1875.Complex 3(C32H38N4Ni,Mr=537.37)belongs to the monoclinic system,space group C2/c with a=19.811(3),b=11.262(2),c=26.004(4)?,the final R=0.0388 and wR=0.1020.The crystal structures indicated that all the NiⅡcomplexes have similar tetra-coordinated geometries,in which the ligand chelated to the center nickel with a 2:1 molar ratio.Catalytic properties of the NiⅡcomplexes for ethylene polymerization were systematically investigated,and the results showed a regular increase of catalytic activities with steric hindrance of the substituents on the imino-aryl ring of NiⅡcomplexes.
基金supported by the Chinese Academy of Sciences,the National Natural Science Foundation of China(Grant No.20371039)National Basic Research Program(the 973 Program,No.2003CB214600)+1 种基金the Key Laboratory Research and Establishment Program of Shaanxi Education Section(No.03JS006)the Natural Science Foundation of Shaanxi Province(Grant No.04JK143).
文摘A series of new complexes {2,6-bis[1-((2-methyl-4-methoxyphenyl)imino)ethyl]pyri-dine}MCI2 [M=Fe(Ⅱ) (2), Co(Ⅱ) (3), Ni(Ⅱ) (4), Cu(Ⅱ) (5), Zn(Ⅱ) (6)] have been synthesized. At 25℃, using 500 equiv of methylaluminoxane (MAO), the activities of Fe(Ⅱ), Co(Ⅱ) catalysts can reach 4.02×106 g/mol-Fehatm for ethylene polymerization and 3.98×105 g/mol-Cohatm for ethylene oligomerization. The effects of polymerization conditions such as reaction temperature, Al/M molar ratio and time on the activity of catalyst have been explored.
