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Highly stereospecific polymerization of isoprene with homogeneous binary Ziegler-Natta catalysts based on NCN-pincer neodymium precursor

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Science china.chemistry 2010年第8期53卷 1641-1645页

作者： LIU DongTao1,2,cui dongmei1 & GAO Wei3 1state key laboratory of polymer physics and chemistry changchun institute of applied chemistry,chinese academy of sciences,changchun 130022,china.2Graduate University of chinese academy of sciences,Beijing 100039,china.3School of chemistry,Jilin University,changchun 130012,china state key laboratory of polymer physics and chemistry changchun institute of applied chemistry Chinese Academy of Sciences Changchun China Graduate University of chinese academy of sciences Beijing China School of chemistry Jilin University Changchun China

The aryldiimine NCN-pincer stabilized neodymium dichloride combined with aluminum alkyls established a new type of homogeneous binary neutral Ziegler-Natta catalyst *** system exhibited high activity and high cis-1,4 selectivity for the polymerization of isoprene (Tp=20 °C,98.2%;Tp=-20 °C,> 99%).Such catalytic performances remained under a broad range of polymerization temperatures and monomer-to-neodymium ratios (from 500 to 8000),reaching high number-average molecular weight (Mn=1582 kg/mol) and relatively narrow molecular weight distribution (PDI=1.68),which was,however,influenced by the amount and bulkiness of aluminum *** investigation of the polymerization was performed,which showed the number-average molecular weight of the resultant polyisoprene had an almost linear correlation with the conversion,suggesting,in some degree,the polymerization with this catalytic system was controllable.

关键词： neodymium cis-1 4 selectivity NCN-pincer complex polyisoprene

Synthesis and Characterization of Scandium Alkyl Complexes with C-H Bond Activations Utilizing Anilido-Phosphinimine Ancillary Ligands

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Synthesis and Characterization of Scandium Alkyl Complexes w...

第十六届全国金属有机化学学术讨论会

作者： Weifeng Rong~1,dongmei cui~(1,*) state key laboratory of polymer physics and chemistry,changchun institute of applied chemistry,chinese academy of sciences,changchun 130022,china.

＜正＞In recent years,the N,N-bidentate ligands have received a great deal of attention because of their fascinating structures as alternatives of pentadienyl ligands,and the attached metal complexes have shown various catalysis towards polymerizations of olefins and conjugated *** we wish to report a series of N,N-bidentate

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Rich C-H Bond Activations of Yttrium Alkyl Complexes Bearing the Phosphinimino-amine ligands

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Rich C-H Bond Activations of Yttrium Alkyl Complexes Bearing...

第十六届全国金属有机化学学术讨论会

作者： Danfeng Li~1,Shihui Li~1,dongmei cui~(1,*),Xuequan Zhang ~1 1 state key laboratory of polymer physics and chemistry,changchun institute of applied chemistry,chinese academy of sciences,changchun 130022,china.

During the past decades,many efforts have been made to develop novel ligands in order to prepare organolanthanide catalyst precursors with unique structure,reactivity,and enhance catalytic activity[1].The use ofβ-dik...

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SELECTIVE SYNTHESIS OF BIODEGRADABLE MATERIALS AND HIGH PERFORMANCE RUBBERS

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SELECTIVE SYNTHESIS OF BIODEGRADABLE MATERIALS AND HIGH PERF...

5th International Symposium on High-Tech polymer Materials

作者： Xinli Liu Shihuili Baoli Wang Wei Gao dongmei cui state key laboratory of polymer physics and chemistry changchun institute of applied chemistry chinese academy of sciences changchun 130022 china.

＜正＞Polylactides （PLAs） are the most promising biodegradable and biocompatible synthetic macromolecules,possessing versatile physical properties and having been widely used in medicine, pharmaceutics and tissue en...

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C-H activation of a N,O-bidentate ligand corresponding to lanthanide metals

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C-H activation of a N,O-bidentate ligand corresponding to la...

第十六届全国金属有机化学学术讨论会

作者： Yang Wang,~(1,2) dongmei cui~(*1) 1 state key laboratory of polymer physics and chemistry,changchun institute of applied chemistry, chinese academy of sciences,5625 Renmin street,changchun 130022,china. 2 Graduate School of the chinese academy of sciences,Beijing 100039,china

＜正＞C-H activation processes mediated by transition metals have been investigated in considerable depth. Developing the chemistry of organometallic rare-earth metal complexes about C-H activation are limited and most of them are focus on Cp and its ***-Cp analogues remained sparse but have received great attention

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Synthesis of Dialkyl Yttrium Complex Supported by Heteroscorpionate Ligand

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Synthesis of Dialkyl Yttrium Complex Supported by Heteroscor...

第十六届全国金属有机化学学术讨论会

作者： Zhichao Zhang~(1,2) and dongmei cui~1 1 state key laboratory of polymer physics and chemistry,changchun institute of applied chemistry,chinese academy of sciences,changchun 130022,People’s Republic of china. 2 Graduate School of the chinese academy of sciences,Beijing 100039,People’s Republic of china.

Synthesis of stable dialkyl rare-earth metal complexes bearing anionic ancillary ligand has been one of the most important research subjects in the past decades since some of these complexes display high selectivity a...

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Coordination polymerization of Renewable (E)-4,8-Dimethyl-1,3,7-Nonatriene by Rare-Earth Metal Catalysts

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chinese Journal of chemistry 2022年第16期40卷 1939-1944页

作者： Yang Jiang Zhen Zhang Shihui Li dongmei cui state key laboratory of polymer physics and chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchunJilin130022 China School of applied chemistry and Engineering University of Science and Technology of ChinaHefeiAnhui230026 China Department of Materials Science and Engineering Jilin UniversityChangchunJilin 130022China

Coordination polymerization of renewable(E)-4,8-dimethyl-1,3,7-nonatriene(DMNT)has been performed using pyridyl-methylene-fluorenyl scandium complex 1,half-sandwich scandium complex 2,diiminophosphinato rare-earth metal complexes 3a—3c and 4a—4b,bis(phosphino)carbazolide yttrium complex 5 andβ-diketiminato yttrium complex *** scandium complexes 1 and 2,activated by[Ph3C][B(C6F5)4]and AliBu3,are moderately active and show perfect 1,2-regioselective(1,2>99%).Conversely,asymmetric diiminophophinato complexes 3a—3c promote the DMNT polymerization to produce high trans-1,4 regulated products with the activity trend:Scpolymerization although they are highly active in isoprene polymerization.A diblock copolymer bearing 3,4-polyisoprene block and trans-1,4-poly(DMNT)block is obtained using complex 3c in one-pot *** of trans-1,4-poly(DMNT)affords an elastomer with a T_(g) of–10 ℃.The epoxidation reaction of trans-1,4-poly(DMNT)with 3-chloroperbenzoic acid transfers the pendant double bonds in the cis configuration into the epoxy groups.

关键词： Biobased monomer Ligand effects Homogeneous catalysis polymerization Elastomer

Self-assisted stereospecific polymerization of unmasked polar 4-methylthio-1-butene

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Science china.chemistry 2019年第6期62卷 761-766页

作者： Yunjie Chai Chunji Wu Dongtao Liu Mingtao Run dongmei cui College of chemistry and Environmental Science Hebei University state key laboratory of polymer physics and chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences

Stereospecific polymerization of polar olefins has always been an attractive but challenging project because the Lewis basic polar groups of monomers are usually poisonous to the Lewis acidic metal centers of the catalysts. In this contribution,thiophene-fused cyclopentadienyl scandium complexes 1-3 were successfully synthesized. Combined with alkylaluminium and organoborate, these complexes showed extremely low activity and no selectivity for 1-hexene polymerization. Surprisingly,highly stereo-selective coordination polymerization of unprotected polar 4-methylthio-1-butene has been achieved in high activity for the first time under the same polymerization conditions. High-molecular-weight(M_n=110×10~3) and perfectly syndiotactic(rrrr>99%) poly(4-methylthio-1-butene)(P(MTB)) was afforded. Thus the methylthio-group-assisted mechanism that the unmasked methylthio group promoted the polymerization through σ-π chelation to the active scandium center together with the vinyl group was proposed. Moreover, the methylsulfonyl functionalized syndiotactic poly(1-butene) was also easily prepared by the oxidation of P(MTB). These results provided a new route for the synthesis of functionalized stereo-regular polyolefins.

关键词： self-assisted polymerization stereoselectivity polar α-olefin rare-earth metal catalyst functionalized poly(1-butene)

A convenient method to prepare random LA/CL copolymers from poly(L-lactide) and ε-caprolactone

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Science china.chemistry 2018年第6期61卷 708-714页

作者： Hao Ouyang Kun Nie Dan Yuan Yong Zhang dongmei cui Yingming Yao key laboratory of Organic Synthesis of Jiangsu Province Suzhou Key Laboratory of Macromolecular Design and Precision Synthesisand State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials College of Chemistry Chemical Engineering and Materials Science Dushu Lake Campus Soochow University School of chemistry and Chemical Engineering Taishan University state key laboratory of polymer physics and chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences

Sequential addition of L-lactide(LA) followed by ε-caprolactone(CL), and simultaneous addition of both monomers, afforded random LA/CL copolymers in the presence of lanthanide aryloxides under mild conditions. Transesterification was proved to play a predominant role in random copolymer formation. Moreover, treatment of poly(L-lactide) with ε-CL led to random copolymer formation, which provides a new strategy not only to prepare random LA/CL copolymers, but also to directly modify PLLA.

关键词： random copolymers lanthanide complex transesterification lactide ε-caprolactone