Article
Chemistry, Multidisciplinary
Beihang Ding, Guanru Chang, Zhengpeng Yan, Shengyu Dai
Summary: Hyperbranched ethylene oligomers and polar functionalized co-oligomers can be synthesized via ethylene chain walking (co) oligomerization, which is an attractive strategy. Dibenzhydryl iminopyridyl ligands with benzocycloalkyl and naphthyl moieties and their corresponding Ni(II) and Pd(II) complexes were synthesized and characterized. The Ni(II) complexes showed high catalytic activity in ethylene oligomerization, while the Pd(II) complexes exhibited moderate activity in ethylene oligomerization and co-oligomerization with methyl acrylate (MA).
FRONTIERS IN CHEMISTRY
(2022)
Article
Chemistry, Physical
Makhosonke Ngcobo, Stephen O. Ojwach
Summary: A series of immobilized complexes were synthesized and characterized using various techniques, showing good catalytic performance in ethylene oligomerization. The type of ligand and metal atom were found to influence the catalytic performance of the complexes, and the immobilized complexes were successfully recycled for multiple uses.
MOLECULAR CATALYSIS
(2021)
Article
Chemistry, Inorganic & Nuclear
Na Zhang, Yuying Li, Liduo Chen, Cuiqin Li, Guoliang Mao, Jun Wang
Summary: A series of star iminopyridine ligands were synthesized, characterized, and used to prepare nickel(II) complexes. These complexes were able to oligomerize ethylene to produce C-4-C-18 fractions, and the catalytic activity and product selectivity were influenced by factors such as substituent, catalyst structure, and reaction conditions. The highest catalytic activity and selectivity of higher carbon olefins were achieved under specific conditions.
JOURNAL OF COORDINATION CHEMISTRY
(2021)
Article
Chemistry, Physical
Adrian Martinez Gomez-Aldaravi, Cecilia Paris, Manuel Moliner, Cristina Martinez
Summary: Diverse Ni-zeolites with different physico-chemical properties and Ni speciation have been designed to study their influence on ethylene oligomerization. Different particle sizes, Si/Al ratios, and Ni-incorporation strategies have been used to synthesize Ni-containing medium-pore MFI and large-pore BEA zeolites. Ni2+ and NiO nanoclusters are found inside the zeolitic pores, depending on the incorporation method. The presence of Ni2+ mainly determines olefin oligomerization under near-ambient pressures, while crystal size, acidity, and Ni incorporation methodology play key roles under high-pressure reaction conditions.
JOURNAL OF CATALYSIS
(2023)
Article
Chemistry, Inorganic & Nuclear
Lei Xu, Jiaxin Li, Wenhua Lin, Yanping Ma, Xinquan Hu, Zygmunt Flisak, Wen-Hua Sun
Summary: These Ni complexes showed high activity in ethylene oligomerization when activated with MMAO or Et2AlCl, with activities reaching 2.23 x 10(6) g.mol(-1) (Ni) h(-1) and 9.11 x 10(5) g.mol(-1) (Ni) h(-1) respectively. High selectivity exceeding 99% for oz-C4 was observed in the Ni/Et2AlCl system.
JOURNAL OF ORGANOMETALLIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Benjamin Yeh, Saumil Chheda, Steven D. Prinslow, Adam S. Hoffman, Jiyun Hong, Jorge E. Perez-Aguilar, Simon R. Bare, Connie C. Lu, Laura Gagliardi, Aditya Bhan
Summary: A mixed-valence oxotrimer metal-organic framework (MOF), Ni-MIL-127, undergoes thermal treatment to generate a defect that enhances its catalytic activity for propylene oligomerization. The catalyst shows unprecedented stability for this chemistry and a majority of the Ni species in the MOF framework are involved in the catalytic reaction. In situ NO titrations and density functional theory calculations support the plausibility of the defect and mechanism. This study highlights the potential of MOF precatalysts in improving catalytic activity.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Benjamin Yeh, Saumil Chheda, Steven D. Prinslow, Adam S. Hoffman, Jiyun Hong, Jorge E. Perez-Aguilar, Simon R. Bare, Connie C. Lu, Laura Gagliardi, Aditya Bhan
Summary: A mixed-valence oxotrimer metal-organic framework (MOF), Ni-MIL-127, with a missing linker defect on the nickel atom catalyzes propylene oligomerization without any cocatalysts or initiators. The catalyst is stable for over 20 hours at 500 kPa and 473 K. The majority of Ni species in the MOF framework catalyze propylene oligomerization, as validated by various analytical techniques.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Polymer Science
Giorgia Zanchin, Alessandro Piovano, Alessia Amodio, Fabio De Stefano, Rocco Di Girolamo, Elena Groppo, Giuseppe Leone
Summary: In addition to the synergy between chromium and the ligand, the nature of the aluminum activator, the presence of the additive, and the polymerization temperature play crucial roles in the polymerization of ethylene. UV-vis-NIR and FT-IR spectroscopic techniques were used to study the activation process and the influence of NEt3 on the catalytic conversion of ethylene. NEt3 interacts with the aluminum cocatalyst to affect the catalytic ion pair formation.
Article
Chemistry, Inorganic & Nuclear
You Ge, Zhou Lu, Shengyu Dai
Summary: In this study, Ni(II) and Pd(II) complexes with bulky 8-alkyl-1-naphthyl substituents were synthesized and evaluated for their effectiveness in ethylene (co)polymerization. The Ni(II) complexes were effective in producing highly branched and high molecular weight polyethylene, while the Pd(II) complexes produced polar functionalized E-MA copolymers with high incorporation ratios. Additionally, the 8-alkyl-1-naphthyl counterparts showed significantly higher polymerization activities and generated polyethylene with comparable molecular weights compared to other counterparts.
Article
Chemistry, Inorganic & Nuclear
Andreea Enachi, Katharina Muenster, Dirk Baabe, Jan Raeder, Matthias Freytag, Peter G. Jones, Winfried P. Kretschmer, Marc D. Walter
Summary: The reactions of tBu3P, Ad3P, and TMPP with allyl-Me and BArF4 were studied, and it was found that despite slight differences in steric bulk and electronic properties, the reaction products were significantly different. TMPP was able to displace the mesitylene ligand, while Ad3P stabilized a two-coordinate Ni(I) species.
Article
Chemistry, Physical
Makhosonke Ngcobo, Alina Ouissa, Wolfgang Kleist, Werner R. Thiel, Stephen O. Ojwach
Summary: Immobilization of the phenol((triethoxysilyl)propylimino) ligand (LH) on SBA15 and MCM41 resulted in the formation of ligands LH-SBA15 and LH-MCM41 respectively. The reactions of these immobilized ligands with NiCl2, CoCl2, and FeCl2 salts yielded the corresponding materials [Ni(LH-SBA15)2Cl2], (Ni-SBA15), [Co(LHSBA15)2Cl2], (Co-SBA15), [Fe(LH-SBA15)2Cl2], (Fe-SBA15) and [Ni(LH-MCM41)2Cl2], (Ni-MCM41) in good yields. The functional group determination, morphology, physical and surface properties of these materials were analyzed through various techniques, and the immobilized catalysts showed good catalytic activity and selectivity in the oligomerization of ethylene.
MOLECULAR CATALYSIS
(2023)
Article
Chemistry, Multidisciplinary
Sergey V. Zubkevich, Vladislav A. Tuskaev, Svetlana Ch. Gagieva, Alexander A. Pavlov, Victor N. Khrustalev, Fei Wang, Li Pan, Yuesheng Li, Daniele Saracheno, Anton A. Vikhrov, Dmitry N. Zarubin, Boris M. Bulychev
Summary: Ten new nickel(11) dibromide complexes with various substituted bis(azolyl)methanes were synthesized and characterized. The complexes exhibited activity in ethylene oligomerization and Friedel-Crafts alkylation processes in the presence of Et2AICI or Et(3)Al(2)C1(3). The use of Et(3)Al(2)C1(3) resulted in a higher share of alkylated products and small amounts of odd carbon number olefins.
CHINESE JOURNAL OF CHEMISTRY
(2023)
Article
Polymer Science
Obaid H. Hashmi, Marc Visseaux, Yohan Champouret
Summary: Isoprene polymerization was successfully conducted using iminopyridine-supported iron complexes in combination with (AlBu3)-Bu-i/[B(C6F5)(4)][CPh3], with ZnEt2 acting as the chain transfer agent. Detailed studies showed that the Mn of polyisoprenes and polymerization rate decrease as the amount of CTA increases, while maintaining catalyst selectivity. These results demonstrate a reversible iron-mediated chain transfer polymerization of isoprene.
Article
Chemistry, Physical
Gabriel V. S. Seufitelli, Jason J. W. Park, Phuong N. Tran, Anthony Dichiara, Fernando L. P. Resende, Rick Gustafson
Summary: The study investigated the kinetics of ethylene oligomerization over Ni-H-Beta catalyst at temperatures between 50 and 100 degrees C and pressures between 5 and 28 atm. The reactions showed different apparent activation energies for butene, hexene, and octene formation, with evidence suggesting that octene formation mainly proceeds via the cascade co-oligomerization of re-adsorbed butene with ethylene.
JOURNAL OF CATALYSIS
(2021)
Article
Polymer Science
Jihoon Kim, Kyeong-Jun Jeong, Kyoungwook Kim, Chang Yun Son, Moon Jeong Park
Summary: Tailor-made end-functional groups were introduced to develop advanced polymer electrolytes for lithium-ion batteries, enhancing electrochemical stability and lithium transference number. Effective interchain coordination interactions improved the electrochemical and mechanical properties of nanostructured polymer electrolytes.
Article
Computer Science, Hardware & Architecture
Jianhai Chen, Huapu Zeng, Yunming Pu
Summary: This paper proposes a feature fusion-based neighbor (FbN) model for calibrating voice sensors using real-time low-cost ambient sensors. By collecting voice data and external low-cost sensor data, selecting and fusing features, and calculating and sorting distances between sensor data and represented features, the calibration is achieved.
JOURNAL OF CIRCUITS SYSTEMS AND COMPUTERS
(2023)
Article
Polymer Science
Yu-Dan Liao, Qi Cai, Sheng-Yu Dai
Summary: In this study, two efficient strategies were employed to retard chain transfer reactions in ethylene polymerization and copolymerization with MA, resulting in the generation of high molecular weight polymers and copolymers.
CHINESE JOURNAL OF POLYMER SCIENCE
(2023)
Article
Genetics & Heredity
Yangying Jia, Jianhai Chen, Jie Zhong, Xuefei He, Li Zeng, Yanmin Wang, Jiakun Li, Shengqian Xia, Erdengqieqieke Ye, Jing Zhao, Bin Ke, Chunyu Li
Summary: Hypoplastic left heart syndrome (HLHS) is a rare and fatal birth defect. A study identified a mutation in the PTPRB gene associated with HLHS.
Article
Orthopedics
Jiabao Ju, Mingtai Ma, Yichong Zhang, Zhentao Ding, Zhongguo Fu, Jianhai Chen
Summary: This study aimed to analyze the fracture line morphology and location relationship of the greater tuberosity (GT) fragments in complicated Neer three- and four-part proximal humerus fractures (PHF). The results showed that the GT fragments exhibited a fan-shaped morphology and could be classified based on their location and morphology. The coverage of GT fragments provided by the locking plate varied depending on the fragment types, and the anterior-avulsion, posterior-avulsion, and posterior-split type GT fragments were identified as high-risk fragments in Neer three- and four-part PHFs.
ORTHOPAEDIC SURGERY
(2023)
Article
Plant Sciences
Kuangyang Yang, Qian Xie, Tingting Tang, Na Zhao, Jianhui Liang, Yanni Shen, Ziqi Li, Ben Liu, Jianhai Chen, Wenxiang Cheng, Xueling Bai, Peng Zhang, Qian Liu, Bing Song, Chun Hu, Lichu Liu, Yan Wang
Summary: In this study, the researchers found that Astragaloside IV (ASN IV), a phytochemical found in Astragalus membranaceus, acts as a novel CXCR4 antagonist, protecting cartilage in osteoarthritis (OA) patients. ASN IV inhibits the overexpression of ADAMTS4,5 in chondrocytes by blocking Akt signaling pathway. Furthermore, ASN IV administration repairs damaged cartilage and subchondral bone in an animal model of OA. This study suggests that repurposing ASN IV as a joint protective agent could be a promising strategy for OA drug development.
Article
Orthopedics
Jiabao Ju, Mingtai Ma, Zhentao Ding, Yichong Zhang, Zhongguo Fu, Jianhai Chen
Summary: This study analyzed the reinforcement effects on the anterior-avulsion GT fragment in Neer three-part proximal humeral fractures using transosseous suture and suture anchor techniques. The results showed that transosseous suture was superior to the suture only in reinforcing the anterior-avulsion GT fragment and had comparable biomechanical strength to the suture anchor.
ORTHOPAEDIC SURGERY
(2023)
Article
Orthopedics
Jian Lin, Wei-Jin Sun, Jian-Hai Chen, Jing-Ming Dong, Ding-Su Bao, Ling Yan, Wei-Dong Ni, Ming Xiang, Jian Ding, Ming Cai, Jia-Xiang Song, Ming-Gui Mao, Xiao-Ming Wu
Summary: This study compared the interobserver agreement of four classification systems for lateral clavicle fractures used by shoulder specialists and general trauma surgeons. The results showed that when 3D-CT scan images were provided, the interobserver agreement was higher in the specialist group using the OTA, Jager/Breitner, and Gongji classification systems, and in the generalist group using the Gongji classification system. Overall, 3D-CT scans provided better results in most classification systems, emphasizing the value of digitization and specialization in diagnosis and treatment.
ORTHOPAEDIC SURGERY
(2023)
Editorial Material
Genetics & Heredity
Jianhai Chen, Nikica Sprem, Yongjie Wu, Shengqian Xia
FRONTIERS IN GENETICS
(2023)
Article
Chemistry, Multidisciplinary
Beihang Ding, Lihang Jiang, Xiaohui Kang, Shengyu Dai
Summary: Usually, bulky steric substituents are needed on both sides of the ortho-aryl position to achieve efficient suppression of chain transfer in aniline-based late-transition-metal catalysts. However, this study demonstrates that a-diimine catalysts based on naphthylamine with only one bulky ortho-aryl substituent also have excellent capabilities to suppress chain transfer. The naphthylamine-based catalysts show superior abilities compared to aniline-based catalysts in suppressing chain transfer reactions and producing high molecular weight (co)polymers in ethylene (co)polymerization.
CHINESE JOURNAL OF CHEMISTRY
(2023)
Article
Polymer Science
Hua Wang, Zhou Lu, Shengyu Dai
Summary: The chain walking polymerization technology is convenient and efficient for the preparation of hyperbranched polyethylene and polar functionalized polyethylene. Two bis(benzocyclopentyl) a-diimine ligands and their corresponding Pd(II) catalysts were synthesized, enabling the polymerization of ethylene to generate hyperbranched polyethylene with low molecular weights and high branching densities. The Pd(II) catalysts also allowed the copolymerization of ethylene with MA to obtain hyperbranched E-MA copolymers with high MA incorporation ratios.
EUROPEAN POLYMER JOURNAL
(2023)
Article
Biochemistry & Molecular Biology
Hui Wang, Weiqing Lu, Mingmin Zou, Shengyu Dai
Summary: Recently, polyolefin thermoplastic elastomers can be directly obtained via alpha-diimine nickel-catalyzed ethylene chain walking polymerization using ethylene as a single feedstock. A range of new bulky acenaphthene-based alpha-diimine nickel complexes were constructed and applied to ethylene polymerization. The activated nickel complexes exhibited good activity and produced polyethylene with high molecular weight and proper branching densities.
Article
Polymer Science
Qi Cai, Fei Fang, Jiangang Gao, Hui Wang, Shengyu Dai
Summary: Three unsymmetrical arylamine based pyridine-imine ligands and their corresponding nickel and palladium complexes were synthesized and investigated for ethylene oligomerization. The nickel complexes showed high catalytic activity, producing highly branched oligoethylenes. The palladium complexes exhibited moderate catalytic activity, yielding low molecular weight oligoethylenes with high branching densities, and also ester functionalized oligoethylenes in ethylene-methyl acrylate co-oligomerization. Compared to fully substituted benzothiophenes, partially benzothiophene substituted pyridineimine catalysts displayed significantly higher activity and produced higher molecular weight oligoethylenes.
EUROPEAN POLYMER JOURNAL
(2023)
Article
Polymer Science
Weiqing Lu, Beihang Ding, Wenping Zou, Shengyu Dai
Summary: Alpha-diimine nickel-catalyzed ethylene chain walking polymerization enables the direct preparation of polyethylene thermoplastic elastomers with high activities and molecular weights. The hybrid bulky butyl-based alpha-diimine nickel complexes with unsymmetrical substituents facilitate the synthesis of significantly higher branched polyethylene with much better elastic recovery. These hybrid cationic nickel catalysts are also capable of catalyzing the copolymerization of ethylene with methyl 10-undecenoate.
EUROPEAN POLYMER JOURNAL
(2023)
Article
Chemistry, Inorganic & Nuclear
Zhou Lu, You Ge, Shengyu Dai
Summary: In this study, two a-diimine ligands and their corresponding nickel and palladium complexes were synthesized and used to explore the effect of axial flexible shielding on ethylene (co)polymerization. The nickel complexes showed high activity and produced lightly branched polyethylenes with high molecular weights, while the palladium complexes exhibited moderate activity and produced highly branched polyethylenes. Moreover, the size of the cycloalkyl ring in the a-diimine catalysts strongly influenced the ethylene (co)polymerization.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Chuangao Zhu, Beihang Ding, Shengyu Dai
Summary: In this study, a series of benzocycloalkyl or naphthyl pyridine-imine Ni(II) complexes with a single o-aryl dibenzosuberyl substituent were synthesized. These complexes exhibited high activity and appropriate molecular weights in ethylene polymerization, while suppressing chain transfer reactions. The resulting branched polyethylene waxes can be used in plastic processing, coating, and dyeing industries.
JOURNAL OF ORGANOMETALLIC CHEMISTRY
(2023)
