Rare earth aryloxides substituted by various alkyl groups [Ln（OAr）3] such as methyl, isopropyl and tertbutyl, were used as single component catalysts to affect ring-opening polymerization of L-lactide （LLA）. The c...Rare earth aryloxides substituted by various alkyl groups [Ln（OAr）3] such as methyl, isopropyl and tertbutyl, were used as single component catalysts to affect ring-opening polymerization of L-lactide （LLA）. The catalytic activity, polymerization characteristics, polymerization kinetics and the mechanism were studied. It was found that the catalytic activity of rare earth aryloxides is influenced by both the structure and the number of alkyl groups on the phenyl ring. The stronger the electron-donation ability of the alkyl group, the higher the catalytic activity will be. An increase in the number of the substitute group will result in a higher catalytic activity. Lanthanum tris（2,4,6-tri-tert-butylphenolate） [La（OTTBP）3] exhibits the highest activity among all lanthanum aryloxides. According to the ^1H-NMR data, it was proposed that the LLA polymerization proceeded via a coordination-insertion mechanism involving cleavage of acyl-oxygen bond of the laetide.展开更多
A series of neutral bimetallic lanthanide aryloxides p-C6H4[OLnL(THF)n]2 [Ln = Y(1), Yb(2), Sm(3)(n = 1) and La(4)(n = 2), L = Me2NCH2CH2N{CH2-(2-O–C6H2–tBu2-3,5)}2] and alkoxides p-C6H4CH2[OLnL(THF)]2 [Ln = Y(5), Y...A series of neutral bimetallic lanthanide aryloxides p-C6H4[OLnL(THF)n]2 [Ln = Y(1), Yb(2), Sm(3)(n = 1) and La(4)(n = 2), L = Me2NCH2CH2N{CH2-(2-O–C6H2–tBu2-3,5)}2] and alkoxides p-C6H4CH2[OLnL(THF)]2 [Ln = Y(5), Yb(6)] supported by an amine-bridged bis(phenolate) ligand have been synthesized through one-pot reactions of Ln(C5H5)3(THF), LH2 with p-benzenediol and 1,4-benzenedimethanol, respectively. All complexes have been fully characterized by elemental analyses, single-crystal X-ray diffraction analysis, and IR and multi-nuclear NMR spectroscopy(in the cases of 1, 4 and 5). Study of their catalytic behavior revealed that, in general, all complexes are efficient initiators for the polymerization of rac-lactide(LA) and rac-β-butyrolactone(BBL), except for 3 and 4 in the case of BBL. The influence imposed by lanthanides of different ionic radii and initiating groups of different structures on the activity, controllability, and stereoselectivity of polymerization were systematically studied and compared. Highly heterotactic PLA(Pr up to 0.99) and syndiotactic PHB(Pr ≈ 0.81) with high molecular weight and narrow polydispersity formed and were automatically capped with hydroxyl functionality at both ends.展开更多
Reaction of SmI2（THF）x with 2 equivalents of NaOAr （Ar = C6H2-tert-Bu3-2,4,6） in THF affords a divalent complex of Sm（OAr）2（THF）yTHF 1 in 90.8% yield. Treatment of 1 with 1,2-dimethoxyethane （DME） leads to t...Reaction of SmI2（THF）x with 2 equivalents of NaOAr （Ar = C6H2-tert-Bu3-2,4,6） in THF affords a divalent complex of Sm（OAr）2（THF）yTHF 1 in 90.8% yield. Treatment of 1 with 1,2-dimethoxyethane （DME） leads to the ligand-exchange reaction, and a DME-solvated complex of Sm（OAr）2（DME）2 2 was obtained. Complex 1 crystallizes in monoclinic, space group P21/c with a = 10.366（5）, b = 33.024（15）, c = 16.123（7） A, β = 93.197（8）°, V = 5511 （4） A^3, Z = 4, C52H90O6Sm, Mr = 961.59, Dc = 1.159 g/cm^3, F（000） = 2048,μ（MoKα） = 1.107 mm^-1, R = 0.0844 and wR = 0.1401 for 4694 observed reflections. Complex 2 crystallizes in monoclinic, space group C2/c with a = 27.222（5）, b = 10.6140（19）, c = 17.398（4） A, β = 110.245（3）°, V = 4716.4（16） A^3, Z = 4, C44H78O6Sm, Mr = 853.41, Dc = 1.202 g/cm^3, F（000） = 1808,μ（MoKα） = 1.285 mm^-1, R = 0.0361 and wR = 0.0830 for 5210 observed reflections.展开更多
The title complex [(ArO)2(THF)Sm(μ-OH)]2?2THF (Ar = C6H2-tBu3-2,4,6) was obtained by the hydrolysis of divalent (ArO)2Sm(THF)3?THF in toluene. It crystallizes in monoclinic, space group P21/c with a = 14.7968(14), b ...The title complex [(ArO)2(THF)Sm(μ-OH)]2?2THF (Ar = C6H2-tBu3-2,4,6) was obtained by the hydrolysis of divalent (ArO)2Sm(THF)3?THF in toluene. It crystallizes in monoclinic, space group P21/c with a = 14.7968(14), b = 18.6981(15), c = 16.8264(17) ?, β = 109.366(2)°, V = 4392.0(7) ?3, Z = 2, C88H150O10Sm2, Mr = 1668.78, Dc = 1.262 g/cm3, F(000) = 1764 and μ(MoKα) = 1.377 mm-1. The final R and wR are 0.0318 and 0.0749, respectively for 9038 observed reflections with I > 2σ(I). The complex possesses a dimeric structure with two centrosymmetric hydroxyl bridges. The samarium atom is coordinated by five oxygen atoms to form a distorted square pyramidal geometry with the average Sm–O(Ar) distance of 2.1757(19) ?. There are H-bond interactions be- tween the molecules.展开更多
The title complex, [(ArO)2Sm(OPPh3)(m-OH)]2 (ArO = 2,6-tBu2-4-Me-C6H2O), was obtained by the hydrolysis reaction of divalent samarium aryloxide, Sm(ArO)2(THF)4, in the presence of triphenylphosphine oxide (OPPh3) in t...The title complex, [(ArO)2Sm(OPPh3)(m-OH)]2 (ArO = 2,6-tBu2-4-Me-C6H2O), was obtained by the hydrolysis reaction of divalent samarium aryloxide, Sm(ArO)2(THF)4, in the presence of triphenylphosphine oxide (OPPh3) in toluene. Crystal data: C96H124O8P2Sm2, Mr = 1768.77, monoclinic, space group P21/n, a = 15.276(6), b = 19.406(9), c = 19.320(7) ? b = 108.59(2), V = 5428(3) 3, Z = 2, Dc = 1.081 g/cm3, F(000) = 1836, T = 293 K, l(MoKa) = 0.71069 ?and m = 11.47 cm-1. The final R = 0.072 and wR = 0.092 for 2456 observed reflections with I ≥ 3s(I). The molecule has a dimeric structure with two centrosymmetric hydroxyl bridges. The samarium atom is coordinated by five oxygen atoms to form a distorted square-pyramid geometry with the average SmO(Ar) distance of 2.18 ?展开更多
The reaction of anhydrous CoCl2 with NaOAr （ArO=2,4,6-tri-tert-butylphenoxo） in THF at room temperature in 1 ： 3 molar ratio afforded anionic cobalt aryloxide [Na（THF）6][Co（OAr）3] （1）. The definite structure ...The reaction of anhydrous CoCl2 with NaOAr （ArO=2,4,6-tri-tert-butylphenoxo） in THF at room temperature in 1 ： 3 molar ratio afforded anionic cobalt aryloxide [Na（THF）6][Co（OAr）3] （1）. The definite structure of this com- plex was characterized by X-ray single crystal diffraction. It was found that this anionic aryloxo cobalt（Ⅱ） complex could effectively initiate the ring-opening polymerization of L-lactide both in solution and in bulk, leading to high molecular weight poly（L-lactide）.展开更多
Tricyclopentylgallium reacted with phenol, naphthol respectively to yield phenox-ide (or naphthoxide) of biscyclopentylgallium which have been characterized by elemental analysis, IR, 1H NMR and mass spectrometry. X-r...Tricyclopentylgallium reacted with phenol, naphthol respectively to yield phenox-ide (or naphthoxide) of biscyclopentylgallium which have been characterized by elemental analysis, IR, 1H NMR and mass spectrometry. X-ray diffraction analysis of compound 1 indicated that it belongs to the monoclinic system, space groups P21/c, with cell constants 0=9.602(3), 6=14.365(7), c=11.256(4)A, and β=97.54(3)°, Z=2(dimers), R=0.0706. Compound 2 assigned to the triclinic system, space groups P1 with cell constants a=9.392(4), 6=9.928(7), c=11.263(7) A, a=112.48(5), β=104.74(4), γ=99.95(5)°, and Z=l(dimers), R=0.0526. The molecule of 1 or 2 contains an oxygen-bridged coplanar Ga2O2 four-membered ring respectively.展开更多
基金supported by the Natural Science Foundation of Shanxi Province(No.2006011069)the Opening Foundation of Key Laboratory of Shanxi Province(No.2009011059-7)
文摘Rare earth aryloxides substituted by various alkyl groups [Ln（OAr）3] such as methyl, isopropyl and tertbutyl, were used as single component catalysts to affect ring-opening polymerization of L-lactide （LLA）. The catalytic activity, polymerization characteristics, polymerization kinetics and the mechanism were studied. It was found that the catalytic activity of rare earth aryloxides is influenced by both the structure and the number of alkyl groups on the phenyl ring. The stronger the electron-donation ability of the alkyl group, the higher the catalytic activity will be. An increase in the number of the substitute group will result in a higher catalytic activity. Lanthanum tris（2,4,6-tri-tert-butylphenolate） [La（OTTBP）3] exhibits the highest activity among all lanthanum aryloxides. According to the ^1H-NMR data, it was proposed that the LLA polymerization proceeded via a coordination-insertion mechanism involving cleavage of acyl-oxygen bond of the laetide.
基金financial supported by the National Natural Science Foundation of China (20972108, 21174095, 21132002)a project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)the Qing Lan Project is gratefully acknowledged
文摘A series of neutral bimetallic lanthanide aryloxides p-C6H4[OLnL(THF)n]2 [Ln = Y(1), Yb(2), Sm(3)(n = 1) and La(4)(n = 2), L = Me2NCH2CH2N{CH2-(2-O–C6H2–tBu2-3,5)}2] and alkoxides p-C6H4CH2[OLnL(THF)]2 [Ln = Y(5), Yb(6)] supported by an amine-bridged bis(phenolate) ligand have been synthesized through one-pot reactions of Ln(C5H5)3(THF), LH2 with p-benzenediol and 1,4-benzenedimethanol, respectively. All complexes have been fully characterized by elemental analyses, single-crystal X-ray diffraction analysis, and IR and multi-nuclear NMR spectroscopy(in the cases of 1, 4 and 5). Study of their catalytic behavior revealed that, in general, all complexes are efficient initiators for the polymerization of rac-lactide(LA) and rac-β-butyrolactone(BBL), except for 3 and 4 in the case of BBL. The influence imposed by lanthanides of different ionic radii and initiating groups of different structures on the activity, controllability, and stereoselectivity of polymerization were systematically studied and compared. Highly heterotactic PLA(Pr up to 0.99) and syndiotactic PHB(Pr ≈ 0.81) with high molecular weight and narrow polydispersity formed and were automatically capped with hydroxyl functionality at both ends.
基金The project was supported by the Qinglan Foundation of Jiangsu Province (HB2001-27) and the Foundation of Educational Commission of Jiangsu Province (04KJD560171)
文摘Reaction of SmI2（THF）x with 2 equivalents of NaOAr （Ar = C6H2-tert-Bu3-2,4,6） in THF affords a divalent complex of Sm（OAr）2（THF）yTHF 1 in 90.8% yield. Treatment of 1 with 1,2-dimethoxyethane （DME） leads to the ligand-exchange reaction, and a DME-solvated complex of Sm（OAr）2（DME）2 2 was obtained. Complex 1 crystallizes in monoclinic, space group P21/c with a = 10.366（5）, b = 33.024（15）, c = 16.123（7） A, β = 93.197（8）°, V = 5511 （4） A^3, Z = 4, C52H90O6Sm, Mr = 961.59, Dc = 1.159 g/cm^3, F（000） = 2048,μ（MoKα） = 1.107 mm^-1, R = 0.0844 and wR = 0.1401 for 4694 observed reflections. Complex 2 crystallizes in monoclinic, space group C2/c with a = 27.222（5）, b = 10.6140（19）, c = 17.398（4） A, β = 110.245（3）°, V = 4716.4（16） A^3, Z = 4, C44H78O6Sm, Mr = 853.41, Dc = 1.202 g/cm^3, F（000） = 1808,μ（MoKα） = 1.285 mm^-1, R = 0.0361 and wR = 0.0830 for 5210 observed reflections.
基金The project was supported by the Qinglan Foundation of Jiangsu Province (HB2001-27)the Foundation of Educational Ministry of Jiangsu Province (04KJD560171)
文摘The title complex [(ArO)2(THF)Sm(μ-OH)]2?2THF (Ar = C6H2-tBu3-2,4,6) was obtained by the hydrolysis of divalent (ArO)2Sm(THF)3?THF in toluene. It crystallizes in monoclinic, space group P21/c with a = 14.7968(14), b = 18.6981(15), c = 16.8264(17) ?, β = 109.366(2)°, V = 4392.0(7) ?3, Z = 2, C88H150O10Sm2, Mr = 1668.78, Dc = 1.262 g/cm3, F(000) = 1764 and μ(MoKα) = 1.377 mm-1. The final R and wR are 0.0318 and 0.0749, respectively for 9038 observed reflections with I > 2σ(I). The complex possesses a dimeric structure with two centrosymmetric hydroxyl bridges. The samarium atom is coordinated by five oxygen atoms to form a distorted square pyramidal geometry with the average Sm–O(Ar) distance of 2.1757(19) ?. There are H-bond interactions be- tween the molecules.
基金Financially supported by NNSFC (20072027) the Education Department of Jiangsu province and the Key Laboratory of Organic Synthesis of Jiangsu province
文摘The title complex, [(ArO)2Sm(OPPh3)(m-OH)]2 (ArO = 2,6-tBu2-4-Me-C6H2O), was obtained by the hydrolysis reaction of divalent samarium aryloxide, Sm(ArO)2(THF)4, in the presence of triphenylphosphine oxide (OPPh3) in toluene. Crystal data: C96H124O8P2Sm2, Mr = 1768.77, monoclinic, space group P21/n, a = 15.276(6), b = 19.406(9), c = 19.320(7) ? b = 108.59(2), V = 5428(3) 3, Z = 2, Dc = 1.081 g/cm3, F(000) = 1836, T = 293 K, l(MoKa) = 0.71069 ?and m = 11.47 cm-1. The final R = 0.072 and wR = 0.092 for 2456 observed reflections with I ≥ 3s(I). The molecule has a dimeric structure with two centrosymmetric hydroxyl bridges. The samarium atom is coordinated by five oxygen atoms to form a distorted square-pyramid geometry with the average SmO(Ar) distance of 2.18 ?
基金Acknowledgement This work was partially supported by the NatxonaL Natural Science Foundation of China （Nos. 21042007, 21172162）, the Nature Science Basic Research of Jiangsu Province for Higher Education （No. 10KJB 150016）, the Priority Academic Program Development of Jiangsu Higher Education Institutions and Key Project in Science and Technology Innovation Cultivation Program of Soochow University.
文摘The reaction of anhydrous CoCl2 with NaOAr （ArO=2,4,6-tri-tert-butylphenoxo） in THF at room temperature in 1 ： 3 molar ratio afforded anionic cobalt aryloxide [Na（THF）6][Co（OAr）3] （1）. The definite structure of this com- plex was characterized by X-ray single crystal diffraction. It was found that this anionic aryloxo cobalt（Ⅱ） complex could effectively initiate the ring-opening polymerization of L-lactide both in solution and in bulk, leading to high molecular weight poly（L-lactide）.
基金Project supported by the National Natural Science Foundation of China and Chinese Academy of Sciences.
文摘Tricyclopentylgallium reacted with phenol, naphthol respectively to yield phenox-ide (or naphthoxide) of biscyclopentylgallium which have been characterized by elemental analysis, IR, 1H NMR and mass spectrometry. X-ray diffraction analysis of compound 1 indicated that it belongs to the monoclinic system, space groups P21/c, with cell constants 0=9.602(3), 6=14.365(7), c=11.256(4)A, and β=97.54(3)°, Z=2(dimers), R=0.0706. Compound 2 assigned to the triclinic system, space groups P1 with cell constants a=9.392(4), 6=9.928(7), c=11.263(7) A, a=112.48(5), β=104.74(4), γ=99.95(5)°, and Z=l(dimers), R=0.0526. The molecule of 1 or 2 contains an oxygen-bridged coplanar Ga2O2 four-membered ring respectively.
