A neutral homoleptic lanthanide amide Yb(NPh 2) 3(THF) 2 was obtained by reaction of anhydrous YbCl 3 with LiNPh 2 in THF. The product was characterized by elemental analysis, infrared spectrum and X-ray crystall...A neutral homoleptic lanthanide amide Yb(NPh 2) 3(THF) 2 was obtained by reaction of anhydrous YbCl 3 with LiNPh 2 in THF. The product was characterized by elemental analysis, infrared spectrum and X-ray crystallographic analysis. The crystal data are monoclinic, P2 1/n space group, a=1.2052(2) nm, b=1.9369(3) nm, c=1.6523(2) nm, β=92.79(1)°, V=3.8524(9) nm 3, Z=4, D c=1.417 g·cm -3, μ=24.67 cm -1 (Mo Kα), F(000)=1668, R=0.036, R w=0.039. The central metal ytterbium is coordinated by three terminal NPh 2 groups and two THF molecules to form a five-coordinate distorted trigonal bipyramid. The mean Yb-N bond length is 0.2219(6) nm.展开更多
The polymerization of acrylonitrile was studied using (diisopropylamido)bis(indenyl) lanthanides, Ind 2LnN(i Pr) 2(Ln=Y, Yb) as a single component catalyst. The effects of the amount of catalyst, monomer concentr...The polymerization of acrylonitrile was studied using (diisopropylamido)bis(indenyl) lanthanides, Ind 2LnN(i Pr) 2(Ln=Y, Yb) as a single component catalyst. The effects of the amount of catalyst, monomer concentration and polymerization temperature on catalytic activity and molecular weight of polyacrylonitrile(PAN) were studied. The results show that the catalytic activity is raised obviously with rising polymerization temperature. The monomer conversion reaches 64% under polymerization temperature, monomer concentration and catalyst concentration are 50 ℃, 5.1 mol·L -1 and 0.3%(molar ratio) sequentially. The conversion and molecular weight of the polymer increase appreciably with adding additive, PhONa. When the molar ratio of PhONa to the catalyst is three, the conversion and the molecular weight is 76% and 1.32×10 4, respectively. The initiation mechanism for the polymerization of acrylonitrile was proposed.展开更多
The reaction of anhydrous YbCl3 with LiNPri2 in 1:3 molar ratio gave the homo- leptic lanthanide amide ate complex Yb(C6H14N)4Li(C4H8O). The crystal structure was determined by X-ray diffraction and the following crys...The reaction of anhydrous YbCl3 with LiNPri2 in 1:3 molar ratio gave the homo- leptic lanthanide amide ate complex Yb(C6H14N)4Li(C4H8O). The crystal structure was determined by X-ray diffraction and the following crystallographic data were obtained: C28H64N4OYbLi, Mg = 652.82, monoclinic, P21/c (#14), a = 15.239(3), b = 21.502(6), c = 21.288(4) ? b = 93.18(2), V = 6964(2) 3, Z = 8, Dc = 1.245 g/cm3, F(000) = 2728 and m(MoKa) = 27.08 cm-1. The final R and Rw are 0.044 and 0.053 for 6765 observed reflections with I > 3.00s(I), respectively. The ytterbium atom is bonded to two terminal amide ligands with the normal YbN distances of 2.171(6) and 2.174(7) ? and two bridging amide ligands with the YbN bonds about 0.1 ?longer than those of the formers, forming a distorted tetrahedral geometry.展开更多
文摘A neutral homoleptic lanthanide amide Yb(NPh 2) 3(THF) 2 was obtained by reaction of anhydrous YbCl 3 with LiNPh 2 in THF. The product was characterized by elemental analysis, infrared spectrum and X-ray crystallographic analysis. The crystal data are monoclinic, P2 1/n space group, a=1.2052(2) nm, b=1.9369(3) nm, c=1.6523(2) nm, β=92.79(1)°, V=3.8524(9) nm 3, Z=4, D c=1.417 g·cm -3, μ=24.67 cm -1 (Mo Kα), F(000)=1668, R=0.036, R w=0.039. The central metal ytterbium is coordinated by three terminal NPh 2 groups and two THF molecules to form a five-coordinate distorted trigonal bipyramid. The mean Yb-N bond length is 0.2219(6) nm.
文摘The polymerization of acrylonitrile was studied using (diisopropylamido)bis(indenyl) lanthanides, Ind 2LnN(i Pr) 2(Ln=Y, Yb) as a single component catalyst. The effects of the amount of catalyst, monomer concentration and polymerization temperature on catalytic activity and molecular weight of polyacrylonitrile(PAN) were studied. The results show that the catalytic activity is raised obviously with rising polymerization temperature. The monomer conversion reaches 64% under polymerization temperature, monomer concentration and catalyst concentration are 50 ℃, 5.1 mol·L -1 and 0.3%(molar ratio) sequentially. The conversion and molecular weight of the polymer increase appreciably with adding additive, PhONa. When the molar ratio of PhONa to the catalyst is three, the conversion and the molecular weight is 76% and 1.32×10 4, respectively. The initiation mechanism for the polymerization of acrylonitrile was proposed.
基金Supported by the National Natural Science Foundation of China (20072027) Department of Education of Jiangsu province and the Key Laboratory of Organic Synthesis of Jiangsu province
文摘The reaction of anhydrous YbCl3 with LiNPri2 in 1:3 molar ratio gave the homo- leptic lanthanide amide ate complex Yb(C6H14N)4Li(C4H8O). The crystal structure was determined by X-ray diffraction and the following crystallographic data were obtained: C28H64N4OYbLi, Mg = 652.82, monoclinic, P21/c (#14), a = 15.239(3), b = 21.502(6), c = 21.288(4) ? b = 93.18(2), V = 6964(2) 3, Z = 8, Dc = 1.245 g/cm3, F(000) = 2728 and m(MoKa) = 27.08 cm-1. The final R and Rw are 0.044 and 0.053 for 6765 observed reflections with I > 3.00s(I), respectively. The ytterbium atom is bonded to two terminal amide ligands with the normal YbN distances of 2.171(6) and 2.174(7) ? and two bridging amide ligands with the YbN bonds about 0.1 ?longer than those of the formers, forming a distorted tetrahedral geometry.
