Bis (4-(4-amino-3, 5-diethylbenzyl)-2, 6-diethylphenylimino) acenaphthene] di- chloronickel (NiLCl2) was prepared and supported on SiO2 modified by methyl trichlorsilane(S-1) and on SiO2-MgCl2/TiCl4 (S-2) re...Bis (4-(4-amino-3, 5-diethylbenzyl)-2, 6-diethylphenylimino) acenaphthene] di- chloronickel (NiLCl2) was prepared and supported on SiO2 modified by methyl trichlorsilane(S-1) and on SiO2-MgCl2/TiCl4 (S-2) respectively. Two supported catalysts S-1 and S-2 used as catalysts for ethylene polymerization were studied and the influences of various polymerization conditions, including the polymerization temperature, cocatalysts, Al/Ni molar ratio on the catalytic activity, branching degree and branch length of PE were also investigated. The experimental results show that the supported catalysts exhibit higher catalytic activity for ethylene polymerization, the highest catalytic activity of S-1 using AlEt2Cl as cocatalyst at 50 ℃, reaching 5.8×10^5gPE/molNi·h, and needed lower Al/Ni molar ratio compared to homogeneous analogue.展开更多
Polyolefins are globally important plastics.Molecular weight and molecular weight distribution are two key parameters for determining the properties of polyolefin materials.In this contribution,we develop a strategy f...Polyolefins are globally important plastics.Molecular weight and molecular weight distribution are two key parameters for determining the properties of polyolefin materials.In this contribution,we develop a strategy for combining the macrocyclic framework and the binuclear effect into the benchmarkα-diimine late transition metal catalysts,and thus macrocyclic binuclearα-diimine nickel catalysts(Ni_(2)-Me and Ni_(2)-iPr)are prepared.Compared to the classical Brookhart's acyclic mononuclearα-diimine nickel analogues(Ni_(1)-Me and Ni_(1)-iPr),these nickel catalysts exhibit enhanced thermostability(up to 110℃)and produce polyethylenes with higher molecular weights(up to 7 times)and lower branching densities(as low as 9 branches/1000C)in methylaluminoxane(MAO)activated ethylene polymerization.This translates into the ability of the catalyst to afford more linear high molecular weight polyethylenes.In particular,bimodal polyethylenes with broad molecular weight distributions(Mw/Mn=8.08-14.66)are generated by the sole catalyst.This work affords diverse polyethylenes.展开更多
Reaction of the N-heterocyclic borane [MeCCHC(CHe)(NAr)2]Btt (1, Ar=2,6-Me2C6H3) with B(C6F5)3 af- forded the zwitterionic hydroborane [MeCCHC(CHz)B(C6F5)3(NAr)2]BH, in which the β-methyl group can be d...Reaction of the N-heterocyclic borane [MeCCHC(CHe)(NAr)2]Btt (1, Ar=2,6-Me2C6H3) with B(C6F5)3 af- forded the zwitterionic hydroborane [MeCCHC(CHz)B(C6F5)3(NAr)2]BH, in which the β-methyl group can be deprotonated with LiN(SiMe3)2 to yield an anionic zwitterionic borenium.展开更多
A series of rhenium(I)diimine alkynyl complexes with various electron-and hole-transporting moieties has been synthesized and characterized.Their electronic absorption,emission and electrochemical properties have also...A series of rhenium(I)diimine alkynyl complexes with various electron-and hole-transporting moieties has been synthesized and characterized.Their electronic absorption,emission and electrochemical properties have also been studied.展开更多
Ethylene oligomerization has been investigated by using catalyst systemscomposed of nickel (II) diimine complexes (diimine = N, N′-o-phenylene bis(salicylideneaminato), N,N′-o-phenyl-enebisbenzal, N, N′-ethylenebis...Ethylene oligomerization has been investigated by using catalyst systemscomposed of nickel (II) diimine complexes (diimine = N, N′-o-phenylene bis(salicylideneaminato), N,N′-o-phenyl-enebisbenzal, N, N′-ethylenebisbenzal) and ethylaluminoxane (EAO). The main productsin toluene and at 110―200℃ were olefins with low carbon numbers (C_4―C_(10)). Effects of reactiontemperature, Al/Ni molar ratio and reaction period on both the catalytic activity and productdistribution were explored. The activity of 1.84 x 10~5 g of oligomer/(mol_(Ni)·h), with 87.4% ofselectivity to C_4―C_(10) olefins, was attained at 200℃ in the reaction when a catalyst composedof NiCl_2-(PhCH= o-NC_6H_4N= CHPh) and EAO was used.展开更多
Preconcentration/separation of Co(II), Fe(III), Pb(II), Cr(IIl), Cu(II) and Cd(II) ions using bis(5-bromo- 2-hydroxy-benzaldehyde)-2-methy1-1,5-pentane diimine (BBHBPDI) on SDS coated alumina has been ...Preconcentration/separation of Co(II), Fe(III), Pb(II), Cr(IIl), Cu(II) and Cd(II) ions using bis(5-bromo- 2-hydroxy-benzaldehyde)-2-methy1-1,5-pentane diimine (BBHBPDI) on SDS coated alumina has been reported. The influences of the analytical parameters including pH, ligand and SDS amount, type and concentration of eluent and sample volume on metal ions recoveries were investigated. At optimum values of all variables the relative standard deviation are between 2.5-2.7 and preconcentration factor was 375, while recoveries for all understudy metal ions are higher than 95%, determination limits are between 1.5-2.7. The method has been successfully applied to determination of Co(II), Fe(III), Pb(II), Cr(III), Cu(II) and Cd(II) ions content in some real samples.展开更多
By using a perylene diimine(PDI)syn-atropisomer as highly preorganized precursor,we successfully constructed a visible-light-active organic macrocycle PDI-M.The formation of macrocyclic structure effectively avoids se...By using a perylene diimine(PDI)syn-atropisomer as highly preorganized precursor,we successfully constructed a visible-light-active organic macrocycle PDI-M.The formation of macrocyclic structure effectively avoids self-aggregation of PDI cores and enhances the absorption in visible region.As a photocatalyst,PDI-M exhibits excellent activity on aerobic selective oxidation of sulfide into sulfoxide under visible light irradiation at room temperature.Mechanism studies show that both superoxide and singlet oxygen act as reactive oxygen species.This work provides a typical case toward the maximum utilization of photosensitive groups under mild conditions.展开更多
基金Funded by the Science Foundation of Guangdong Province (No.031598)
文摘Bis (4-(4-amino-3, 5-diethylbenzyl)-2, 6-diethylphenylimino) acenaphthene] di- chloronickel (NiLCl2) was prepared and supported on SiO2 modified by methyl trichlorsilane(S-1) and on SiO2-MgCl2/TiCl4 (S-2) respectively. Two supported catalysts S-1 and S-2 used as catalysts for ethylene polymerization were studied and the influences of various polymerization conditions, including the polymerization temperature, cocatalysts, Al/Ni molar ratio on the catalytic activity, branching degree and branch length of PE were also investigated. The experimental results show that the supported catalysts exhibit higher catalytic activity for ethylene polymerization, the highest catalytic activity of S-1 using AlEt2Cl as cocatalyst at 50 ℃, reaching 5.8×10^5gPE/molNi·h, and needed lower Al/Ni molar ratio compared to homogeneous analogue.
基金This work was supported by the National Natural Science Foundation of China(No.22122110)the Science and Technology Department Program of Jilin Province,China(No.20230101347JC).
文摘Polyolefins are globally important plastics.Molecular weight and molecular weight distribution are two key parameters for determining the properties of polyolefin materials.In this contribution,we develop a strategy for combining the macrocyclic framework and the binuclear effect into the benchmarkα-diimine late transition metal catalysts,and thus macrocyclic binuclearα-diimine nickel catalysts(Ni_(2)-Me and Ni_(2)-iPr)are prepared.Compared to the classical Brookhart's acyclic mononuclearα-diimine nickel analogues(Ni_(1)-Me and Ni_(1)-iPr),these nickel catalysts exhibit enhanced thermostability(up to 110℃)and produce polyethylenes with higher molecular weights(up to 7 times)and lower branching densities(as low as 9 branches/1000C)in methylaluminoxane(MAO)activated ethylene polymerization.This translates into the ability of the catalyst to afford more linear high molecular weight polyethylenes.In particular,bimodal polyethylenes with broad molecular weight distributions(Mw/Mn=8.08-14.66)are generated by the sole catalyst.This work affords diverse polyethylenes.
基金We are grateful to the National Natural Science Foundation of China (Grant Nos. 21390401 and 21472098) and 973 Program (Grant No. 2012CB821600) for support of this work.
文摘Reaction of the N-heterocyclic borane [MeCCHC(CHe)(NAr)2]Btt (1, Ar=2,6-Me2C6H3) with B(C6F5)3 af- forded the zwitterionic hydroborane [MeCCHC(CHz)B(C6F5)3(NAr)2]BH, in which the β-methyl group can be deprotonated with LiN(SiMe3)2 to yield an anionic zwitterionic borenium.
文摘A series of rhenium(I)diimine alkynyl complexes with various electron-and hole-transporting moieties has been synthesized and characterized.Their electronic absorption,emission and electrochemical properties have also been studied.
文摘Ethylene oligomerization has been investigated by using catalyst systemscomposed of nickel (II) diimine complexes (diimine = N, N′-o-phenylene bis(salicylideneaminato), N,N′-o-phenyl-enebisbenzal, N, N′-ethylenebisbenzal) and ethylaluminoxane (EAO). The main productsin toluene and at 110―200℃ were olefins with low carbon numbers (C_4―C_(10)). Effects of reactiontemperature, Al/Ni molar ratio and reaction period on both the catalytic activity and productdistribution were explored. The activity of 1.84 x 10~5 g of oligomer/(mol_(Ni)·h), with 87.4% ofselectivity to C_4―C_(10) olefins, was attained at 200℃ in the reaction when a catalyst composedof NiCl_2-(PhCH= o-NC_6H_4N= CHPh) and EAO was used.
文摘Preconcentration/separation of Co(II), Fe(III), Pb(II), Cr(IIl), Cu(II) and Cd(II) ions using bis(5-bromo- 2-hydroxy-benzaldehyde)-2-methy1-1,5-pentane diimine (BBHBPDI) on SDS coated alumina has been reported. The influences of the analytical parameters including pH, ligand and SDS amount, type and concentration of eluent and sample volume on metal ions recoveries were investigated. At optimum values of all variables the relative standard deviation are between 2.5-2.7 and preconcentration factor was 375, while recoveries for all understudy metal ions are higher than 95%, determination limits are between 1.5-2.7. The method has been successfully applied to determination of Co(II), Fe(III), Pb(II), Cr(III), Cu(II) and Cd(II) ions content in some real samples.
基金supported by the National Natural Science Foundation of China(No.22171021)Yanjing Young Scholar Candidate Program of Capital Normal University,Capacity Building for SciTech Innovation-Fundamental Scientific Research Funds.
文摘By using a perylene diimine(PDI)syn-atropisomer as highly preorganized precursor,we successfully constructed a visible-light-active organic macrocycle PDI-M.The formation of macrocyclic structure effectively avoids self-aggregation of PDI cores and enhances the absorption in visible region.As a photocatalyst,PDI-M exhibits excellent activity on aerobic selective oxidation of sulfide into sulfoxide under visible light irradiation at room temperature.Mechanism studies show that both superoxide and singlet oxygen act as reactive oxygen species.This work provides a typical case toward the maximum utilization of photosensitive groups under mild conditions.