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4-Amino-1,2,4-triazole Resin-supported Palladium Complex as Phosphine-free Catalyst for Suzuki Reaction in Aqueous Phase

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Chemical Research in Chinese Universities 2010年第2期26卷 331-334页

作者： WU xiang-mei wang Yan GUO Sheng-rong College of Chemistry and Life Science Lishui University Lishui 323000 P. R. China

1 Introduction The Suzuki cross-coupling reaction is a powerful and versatile method for the generation of unsymmetrical biaryls from arylboronic acids and aryl halides in a single step. However, the reaction is usually performed in the presence of Pd catalyst along with phosphine ligand, which sometimes creates practical problems because organophosphines tend to be expensive, poisonous, and air sensitive. Recently, phos-phine-free ligands,

关键词： Suzuki reaction Phosphine-free ligand Palladium 4-Amino-1,2,4-triazole resin

Construction and Functionalization of Highly Strained N-Doped Zigzag Hydrocarbon Belts

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CCS Chemistry 2023年第1期5卷 117-123页

作者： Ming Xie Shuo Tong mei-xiang wang MOE Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology Department of ChemistryTsinghua UniversityBeijing 100084

Recent years have witnessed breakthroughs in the study of zigzag hydrocarbon ***,the synthesis of heterocycle-containing zigzag molecular belts remains very rare and challenging despite their interesting structures and potential applications in chemistry and materials ***,we report the expeditious construction of a highly strained belt[4]arene[4](1,4-dihydropyridine)structure using the fjords-stitching *** synthesis comprised four-fold abnormal m-bromination of four Npivaloylaniline units and Pd_(2)(dba)_(3)/4-Me_(2)NC_(6)H_(4)Pt Bu_(2)-catalyzed intramolecular C-N bond-forming *** functionalization through Narylations produced a variety of tetraza-embedded octahydrobelt[8]*** oxidation of p-methoxyphenyl-substituted belt[4]arene[4](1,4-dihydropyridine)with Ag[Al(O^(t)Bu^(F))^(4)]yielded a singlet diradical dication N-doped zigzag belt.

关键词： zigzag molecular belt cyclacene octahydrobeltarenepyridine meta-bromination of Nacylaniline palladium-catalyzed C-N bond formation diradical dication salt

Zigzag Hydrocarbon Belts

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CCS Chemistry 2021年第2期3卷 916-931页

作者： Tan-Hao Shi mei-xiang wang MOE Key Laboratory of Bioorganic Phosphorous and Chemical Biology Department of ChemistryTsinghua UniversityBeijing 100084

Zigzag hydrocarbon belts have been fascinating chemists and materials scientists for decades because of their aesthetically appealing molecular structures,outstanding physical properties and intriguing chemical reactivities predicted by theoretical calculations,and potential applications as unique macrocyclic hosts in supramolecular *** may also serve as templates or seeds to grow structurally well-defined uniform zigzag carbon *** there have been continuous computational studies on the structures and properties of belt[n]arenes or[n]cyclacenes since they were proposed as hypothetical molecules in 1954,the synthesis of(partially)conjugated zigzag hydrocarbon belts remains a great challenge,with no progress being reported in the past 20 *** recently,we have been witnessing the renaissance of synthetic interest in zigzag hydrocarbon belts,and the formation of the first fully conjugated one is on the *** minireview focuses on the understanding of belt[n]arenes based on theoretical calculations and the synthesis and structure of zigzag hydrocarbon *** on the strategies to isolate and characterize the fully conjugated belt[n]arenes and on the applications of zigzag hydrocarbon belts are also discussed.

关键词： zigzag hydrocarbon belt belt[n]arene [n]cyclacene macrocycle carbon nanotube cyclization Diels–Alder reaction intramolecular alkylation

Prediction of Rolling Load, Recrystallization Kinetics, and Microstructure During Hot Strip Rolling

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Journal of Iron and Steel Research International 2007年第6期14卷 42-46页

作者： XU Yun-bo YU Yong mei LIU xiang-hua wang Guo-dong State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China

The recrystallization kinetics and grain size models were developed for the C Mn and niobium containing steels to describe the metallurgical phenomenon such as softening, grain growth, and strain accumulation. Based on the recrystallization kinetics equations, the mean flow stress and the rolling load of each pass were predicted and the optimum rolling schedule was proposed for hot strip rolling. The austenite grain refinement is associated with the addition of niobium, the decrease of starting temperature of finish rolling, and the reduction of finished thickness. The mean flow stress curve with a continuous rising characteristic can be usually observed in the finish rolling of niobium containing steel, which is formed as a result of the heavy incomplete softening and strain accumulation. The predic ted rolling loads are in good agreement with the measured ones.

关键词： hot strip rolling recrystallization mean flow stress strain accumulation grain size

Computer Model of Phase Transformation From Hot-Deformed Austenite in Niobium Microalloyed Steels

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Journal of Iron and Steel Research International 2007年第2期14卷 66-69页

作者： XU Yun-bo YU Yong-mei LIU xiang-hua wang Guo-dong State Key Lab of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China

Based on thermodynamics and kinetics, a new mathematical model was developed to calculate the CCT diagrams and the transformation kinetics in low carbon niobium steels, in which the effect of deformation on the degree of supercooling was taken into account. The undercooling caused by deformation is the major reason for the increase of the starting transition temperature during continuous cooling. The critical cooling rate of bainite formation is within 2--5 ℃s for the studied niobium steels and deformation is suitable for the occurrence of pearlite. The ferrite volume fraction increases with the increase of the austenite boundary area, and decreases with the increase of the cooling rate. The calculated CCT diagrams and the volume fraction of each phase are in good agreement with the measurements.

关键词： low carbon niobium steel thermodynamics supercooling degree continuous cooling transformation computer model

Thermodynamic Calculation of Carbide Precipitate in Niobium Microalloyed Steels

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Journal of Iron and Steel Research International 2006年第6期13卷 53-56页

作者： XU Yun-bo YU Yong-mei LIU xiang-hua wang Guo-dong State Key Lab of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China

On the basis of regular solution sublattice model, thermodynamic equilibrium of austenite/carbide in Fe-Nb-C ternary system was investigated. The equilibrium volume fraction, chemical driving force of carbide precipitates and molar fraction of niobium and carbon in solution at different temperatures were evaluated respectively. The volume fraction of precipitates increases, molar fraction of niobium dissolved in austenite decreases and molar fraction of carbon increases with decreasing the niobium content. The driving force increases with the decrease of temperature, and then comes to be stable at relatively low temperatures. The predicted ratio of carbon in precipitates is in good agreement with the measured one.

关键词： microalloyed steel thermodynamic calculation phase equilibrium carbide prediction model

Synthesis of O6-Corona[3]arene[3]pyridazines and Their Molecular Recognition Property in Organic and Aqueous Media

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Chinese Journal of Chemistry 2018年第7期36卷 630-634页

作者： Yao Lu Dong-Dong Liang Zhan-Da Fu Qing-Hui Guo mei-xiang wang Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education) Department of Chemistry Tsinghua University Beijing 100084 China

O6-Corona[3]arene[3]pyridazines were synthesized from the one-pot macrocyclic condensation reaction of 3,6-dichlorotetrazine with 1,4-dihydroquinone derivatives followed by the inverse electron demand Diels-Alder reaction of the tetrazine rings with a cyclopentanone-derived enamine. Conversion of six ester groups within macrocycle into all sodium acetate moieties afforded a water soluble O6-corona[3]arene[3]pyridazine. The coronary macrocycle host formed complexes selectively with organic ammoniums and dinitrile guests in a 1 ： 1 stoichiometric ratio in organic solvents with association constants ranging from （2.96± 0.10）× 10^1 to （2.53±0.33）× 10^5 L·mol^-1. Water soluble O6-corona[3]arene[3]pyridazine was also able to complex strongly with organic ammoniums in water to give an association constant up to （2.67 ± 0.21） × 10^4 L·mol^-1. The pseudo-rotaxane and inclusion structures of the host-guest complexes were revealed by the X-ray crystallography.

关键词： coronarene O6-coronaarenepyridazine inverse electron demand Diels-Alder reaction molecular recognition organic ammonium dinitrile

THE REACTION OF ETHYL AROYLACETATES AND o-PHENYLENEDIAMINE

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Chinese Chemical Letters 1993年第1期4卷 9-11页

作者： mei xiang wang Zhi Tang HUANG Institute of Chemistry Academia SinicaBeijing 100080

Instead of 2-(aroylmethylene)benzimidazolines 3 or 2-(aroyl-methyl)benzimidazoles 4, 4-aryl-2, 3-dihydro-1H-1, 5-benzodiazepin-2-ones 5 were obtained exclusively from the reaction of o-phenylenediamine (1) and ethyl a... 详细信息

关键词： wang THE REACTION OF ETHYL AROYLACETATES AND o-PHENYLENEDIAMINE

Inherently Chiral and Symmetrical Heteroatom-Doped Zigzag-Type Hydrocarbon Belts

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CCS Chemistry 2024年第5期6卷 1198-1210页

作者： Xue-Yuan wang Xin-Yu Zhang Shuo Tong Qing-Hui Guo mei-Ling Tan Cheng-Jun Li mei-xiang wang Key Laboratory of Bioorganic Phosphorous Chemistry and Chemical Biology(Ministry of Education) Department of ChemistryTsinghua UniversityBeijing 100084

hydrocarbon belts due to their potential applications in carbon *** contrast,heteroatomembedded zigzag hydrocarbon belts as advanced design strategies with fascinating structures and desirable,unique properties have remained largely unexplored,and inherently chiral ones are ***,we report the synthesis of a diversity of symmetric and highly enantiopure inherently chiral O-and N-doped zigzag-type hydrocarbon belts starting from strainless macrocycles based on fjord-stitching *** readily available pertriflated resorcin[6]arene underwent partial hydrolyses and intramolecular S_(N)Ar reactions to form a calix[3](9H-xanthene)derivative and a prochiral half-belt *** transformations of calix[3](9H-xanthene)into C_(3v)-symmetric molecular belts were achieved by closing the rest of the fjords with triple intramolecular S_(N)Ar reactions and Yamamoto homo coupling reactions,as well as palladiumcatalyzed intermolecular acridination reactions with primary *** prochiral half-belt underwent enantioselective desymmetrizative mono-acridination to afford an inherently chiral N,O_(4)-bridged pseudo-belt with an enantiomeric excess(ee)value of>99%under the catalysis of Pd(OAc)_(2)and(R)-*** closure reactions of the pseudo-belt produced diverse heteroatom-inlayed zigzag-type hydrocarbon belts of inherent ***,we showed the unique cavity structures of the belts and demonstrated interesting chiroptic properties of the inherently enantiopure chiral *** research opens the door for the exploration of novel and sophisticated symmetric and inherently chiral molecular nanobelt structures with outstanding physical and chemical properties,as well as potential applications.

关键词： zigzag-type molecular belt heterocycle chiroptical property fjord-stitching strategy resorcinarene