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Partners in Epoxide Copolymerization Catalysis:Approach to High Activity and Selectivity

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Chinese Journal of Polymer Science 2022年第11期40卷 1331-1348页

作者： xiao-bing lu Bai-Hao Ren State Key Laboratory of Fine Chemicals Dalian University of TechnologyDalian 116024China

The ring-opening alternating copolymerization processes of epoxides with small-molecule monomers,such as carbon dioxide(CO_(2)),carbonyl sulfide(COS)and cyclic anhydrides,are powerful strategies for preparing polymeric materials with degradable carbonate/ester/thiocarbonate main-chain backbone *** catalysts selected for copolymerization processes play crucial roles in determining their reaction rates and productivities,as well as the selectivity,regio-and stereochemistry,compositions,and the molecular weights of their resultant *** processes often generate undesirable byproducts such as polyether or ether linkages dispersed randomly within the copolymer's chain,and/or more thermodynamically stable cyclic *** this account,we outline our efforts of over a dozen years on developing highly active well-defined metal catalysts based on inter-and intra-molecular synergistic strategies to selectively produce completely alternating copolymers from epoxides and various small-molecule *** attention was paid to the enantioselective resolution copolymerization processes of racemic epoxides via regioselective ring-openings,and the asymmetric copolymerization processes of meso-epoxides with CO_(2),COS,or cyclic anhydrides via dissymmetrical ring-openings using multichiral catalytic systems,and affording isotactic copolymers with main-chain *** addition,this account provides a thorough mechanistic understanding of the high reactivities,excellent selectivity,and unprecedented stereochemical controls of these copolymerization systems,mediated by interand intramolecular synergistic catalysis.

关键词： Epoxide Ring-opening copolymerization Synergistic catalysis CO_(2) Stereochemistry control

DBU-Mediated Carboxylative Coupling of Primary Amines,Carbon Dioxide and Propargyl Chlorides

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Chinese Journal of Chemistry 2015年第5期33卷 610-613页

作者： Wen-Zhen Zhang Xiang Ren xiao-bing lu State Key Laboratory of Fine Chemicals Dalian University of TechnologyDalianLiaoning 116024China

A carboxylative coupling reaction of various primary amine and 3-phenyl-2-propynyl or 2-nonynyl chloride in the presence of 8-diazabicyclo[5.4.0]undec-7-ene(DBU)using carbon dioxide as carboxylative reagent was *** transition-metal free reaction system shows broad substrate scope and gives a series of propargylcarbamates in moderate to good *** obtained N-alkyl substituted carbamate product can undergo base-catalyzed intramolecular cyclization reaction to afford functionalized 4-methylene-2-oxazolidinone in good yield.

关键词： carbon dioxide fixation amines propargylchlorides carboxylative coupling transition-metal free

Enantioselective Resolution Copolymerization of Racemic 2,3-Disubstituted cis-Epoxides with CO_(2) Mediated by Binuclear Cobalt(Ⅲ)Catalyst

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Chinese Journal of Chemistry 2021年第9期39卷 2386-2390页

作者： Yan-Lan Liu Guang-Hui He Ye Liu xiao-bing lu State Key Laboratory of Fine Chemicals Dalian University of TechnologyDalianLiaoning 116024China

Enan tioselective resoluti on copolymerization of racemic internal epoxides with carb on dioxide(CO_(2))is a challe nging issue because of their poor reactivity and complicated regio/***,we describe the first enantioselective resolution copolymeriza-tion of racemic aromatic 2,3-disubstituted c/s-epoxides and CO_(2) using enantiopure dinuclear cobalt(lll)complexes as catalyst under mild conditions,affordi ng the corresp on ding polycarbonates with completely alter nating structure and good enantioselectivity in the range of 70% to 97%*** isotactic polycarb on ate from/3-methylstyre ne oxide is a typical semicrystalli ne material,possessi ng a melting point of 241℃;while other isotactic-enriched copolymers from 2,3-disubstituted c/s-epoxides bearing a substitute group on the aromatic ring are amorphous,having glass transition temperatures between 86℃ and 124℃.Interestingly,the copolymer selectivity is correlated well with the Hammett substituent constant,and the highest polymer selectivity of 98%was found in the system using the epoxides bearing an electron-donating group on the benzene ring.

关键词： Asymmetric catalysis Internal c/s-epoxides Carbon dioxide fixation Polymerization Hammett constant

Recent advances in electrochemical carboxylation reactions using carbon dioxide

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Green Chemical Engineering 2022年第2期3卷 125-137页

作者： xiao-Fei Liu Ke Zhang Li Tao xiao-bing lu Wen-Zhen Zhang State Key Laboratory of Fine Chemicals Dalian University of TechnologyDalian116024China

From the viewpoint of abundance,economy,non-toxicity,and renewability,CO_(2) is the ideal C1 synthon in organic synthetic *** CO_(2) for chemical conversion to synthesize highly value-added fine chem-icals is of great *** electrochemical synthesis that employs electrons as redox reagents to achieve selective oxidation or reduction has attracted much attention in the past *** this review,recent advances in the electrochemical carboxylations using CO_(2) from the perspective of organic synthesis will be *** give an overview about the research progress of electrocarboxylation reactions according to the classification of substrates,such as alkenes,organic(pseudo)halides,aldehydes,ketones,and *** carb-anions produced by cathodic reduction are important intermediates in the electrocarboxylation reactions using CO_(2).

关键词： Carbon dioxide Organic electrochemical synthesis Carboxylation Green chemistry Carboxylic acid

Acid-base cooperativity of heterogeneous catalyst containing acidic framework and sterically hindered base for aldol condensation

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Chinese Chemical Letters 2009年第9期20卷 1051-1054页

作者： Hua Li Shu Tao Xu xiao bing lu Wei Ping Zhang State Key Laboratory of Fine Chemicals Dalian University of Technology Dalian 116012 China State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China

A bifunctional heterogeneous catalyst containing two mutually incompatible acidic and basic sites, which exhibits cooperative catalytic behavior in the aldol condensation of acetone and various aldehydes, was synthesized by postgrafting of 1,5,7- triazabicyclo[4.4.0] dec-5-ene （TBD, a sterically hindered organic base） onto AI-MCM-41 molecular sieve. 2009 xiao bing lu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

关键词： Bifunctional catalyst Acid-base cooperative catalysis Mesoporous material Aldol reaction

Experimental study on mechanical properties of methane-hydrate-bearing sediments

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Acta Mechanica Sinica 2012年第5期28卷 1356-1366页

作者： Xu-Hui Zhang xiao-bing lu Li-Min Zhang Shu-Yun Wang Qing-Ping Li Laboratory for Hydrodynamics and Ocean Enginnering Institute of MechanicsChinese Academy of Sciences Department of Civil and Environmental Engineering Hong KongUniversity of Science and Technology Research Centre China Ocean Oil Co.

Mechanical properties of methane hydrate- bearing-sediments （MHBS） are basic parameters for safety analysis of hydrate exploration and exploitation. Young＇s modulus, cohesion, and internal friction angle of hydrate- bearing sediments synthesized in laboratory, are investigated using tri-axial tests. Stress-strain curves and strength parameters are obtained and discussed for different compositions and different hydrate saturation, followed by empirical expressions related to the cohesion, internal friction angle, and modulus of MHBS. Almost all tested MHBS samples exhibit plastic failure. With the increase of total saturation of ice and methane hydrate （MH）, the specimens＇ internal friction angle decreases while the cohesion increases.

关键词： Gas hydrate sediment. Tri-axial test. Cohesion Internal friction angle Elastic modulus

Capsid protein from red-spotted grouper nervous necrosis virus induces incomplete autophagy by inactivating the HSP90ab1-AKT-MTOR pathway

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Zoological Research 2022年第1期43卷 98-110页

作者： Wan-Wan Zhang Peng Jia xiao-bing lu xiao-Qi Chen Jue-Hua Weng Kun-Tong Jia Mei-Sheng Yi School of Marine Sciences Sun Yat-sen UniversityGuangzhouGuangdong 510000China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) ZhuhaiGuangdong 519000China Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering GuangzhouGuangdong 510000China Pearl River Estuary Marine Ecosystem Research Station Ministry of EducationZhuhaiGuangdong 519000China

As a highly important fish virus,nervous necrosis virus(NNV)has caused severe economic losses to the aquaculture industry ***,an evolutionarily conserved intracellular degradation process,is involved in the pathogenesis of several *** NNV can induce autophagy to facilitate infection in grouper fish spleen cells,how it initiates and mediates autophagy pathways during the initial stage of infection is still ***,we found that red-spotted grouper NNV(RGNNV)induced autophagosome formation in two fish cell lines at 1.5 and 3 h post infection,indicating that autophagy is activated upon entry of ***,autophagic detection showed that RGNNV entry induced incomplete autophagy by impairing the fusion of autophagosomes with *** investigation revealed that binding of the RGNNV capsid protein(CP)to the Lateolabrax japonicus heat shock protein HSP90ab1(LjHSP90ab1),a cell surface receptor of RGNNV,contributed to RGNNV invasion-induced ***,we found that CP blocked the interaction of *** protein kinase B(AKT)with LjHSP90ab1 by competitively binding the NM domain of LjHSP90ab1 to inhibit the AKT-mechanistic target of the rapamycin(MTOR)*** study provides novel insight into the relationship between NNV receptors and autophagy,which may help clarify the pathogenesis of NNV.

关键词： NNV Autophagy CP HSP90ab1 AKT-MTOR pathway

Highly active bifunctional salenTi(Ⅳ) catalysts for asymmetric cyanosilylation of aldehydes and TMSCN

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Chinese Chemical Letters 2011年第11期22卷 1285-1288页

作者： Ye Qian Wen Wei Min Ren xiao bing lu State Key Laboratory of Fine Chemicals Dalian University of Technolog3 Dalian 116024 China

A novel enantiopure salen ligand bearing a diphenylphosphine oxide on the 3-position of one aromatic ring was synthesized and combined with Ti（Oi-Pr）_4 as a monometallic bifunctional catalyst for asymmetric cyanosilylation reaction of aldehydes with tnmethylsilyl cyanide（TMSCN）.The catalyst system exhibited excellent activity and moderate *** addition of TMSCN to 4-nitrobenzaldehyde in the presence of 1 mol%catalyst loading could complete within 10 min at ambient temperature. An intramolecularly cooperative catalysis was observed in this system wherein the central metal Ti（Ⅳ） is suggested to play a role of Lewis acid to activate aldehydes while the appended diphenylphosphine oxide worked as Lewis base to activate TMSCN.

关键词： Cyanohydnn Bifunctional catalyst Salen TMSCN Diphenylphosphine oxide

Unveiling chain–chain interactions in CO2-based crystalline stereocomplexed polycarbonates by solid-state NMR spectroscopy and DFT calculations

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Journal of Energy Chemistry 2018年第2期27卷 361-366页

作者： Zhenchao Zhao Pengju Ren Ye Liu Kangbo Zhao xiao-bing lu Weiping Zhang State Key Laboratory of Fine Chemicals School of Chemical Engineering Dalian University of Technology Dalian 116024 Liaoning China Srate Key Laboratory of Coal Conversion Institute of Coal Chemistry Chinese Academy of Sciences Taiyuan 030001 Shanxi China national Energy Center for Coal to Clean Fuels Synfuels China Co. Ltd Huairou District Beijing 101400 China

CO2-based stereocomplexed polycarbonates derived from the intermolecularly interlocked interaction between the enantiopure polymers with the opposite configuration exhibit high crystallinity, excellent thermal and mechanical stabilities. Deep insights into the mechanism of stereocomplexation are of particular importance to the design and manufacture of new promising and sustainable polycarbonates with enhanced physicochemical properties. Our solid-state NMR experiments linking with DFT computations clearly reveal the specific chain-chain interactions in a typical stereocomplexed poly（4,4-dimethyl-3,5,8-trioxabicyclo[5.1.0] octane carbonate）（PCXC）.13C CP/MAS NMR,1H DUMBO MAS NMR and 13C/1H relaxation-time measurements indicate that the formation of stereocomplex reduces the local mobilities of carbonyl, methine and methylene groups in each chain of PCXC significantly. Through a combination of two-dimensional 1H-13C HETCOR NMR and DFT calculation analysis, the cis-/trans-conformations and packing models of PCXC chains in the amorphous, enantionpure isotactic and stereocomplexed polycarbonates are identified. The splitting of 13C and 1H NMR chemical shifts of methine groups in the backbone carbon region demonstrates the ordered interlock interactions between the R-and S-chain in the stereocomplexed PCXC.

关键词： Stereocomplexed polycarbonates Crystalline carbonate polymers Stacking interaction Solid-state NMR DFT