Article
Chemistry, Inorganic & Nuclear
You Ge, Shuaikang Li, Weigang Fan, Shengyu Dai
Summary: In this study, novel α-diiminenickel and -palladium complexes containing flexible 8-alkylnaphthyl were investigated for their catalytic performance in ethylene polymerization. The nickel complexes displayed high activity and generated branched polyethylenes with broad or bimodal molecular weight distributions, while the palladium complexes showed moderate activity, producing highly branched polyethylenes with narrow molecular weight distributions. Additionally, the palladium complexes achieved highly branched E-MA copolymers with considerable MA incorporations, indicating their potential in copolymerization reactions. Compared to their rigid 8-arylnaphthyl counterparts, the flexible 8-alkylnaphthyl complexes exhibited significantly improved activity and produced lower or comparable molecular weight polyethylenes or E-MA copolymers.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Ao Chen, Daohong Liao, Changle Chen
Summary: A novel diaryl-methyl aniline with multiple tert-butyl groups and its derivatives were prepared in this study, showing excellent solubility and catalytic properties with nickel catalysts in aliphatic hydrocarbon solvents, potentially bridging academic research with practical applications in polymerization.
CHINESE JOURNAL OF CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Shi-Yu Chen, Bai-Hao Ren, Shi-Huan Li, Yu-Hang Song, Shuang Jiao, Chen Zou, Changle Chen, Xiao-Bing Lu, Ye Liu
Summary: Transition-metal-catalyzed copolymerization produces polyketones materials with excellent properties. This study successfully synthesized a series of cationic P,O-coordinated Ni complexes catalysts with outstanding performance, which is a significant discovery in the field of Ni catalysts.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Polymer Science
Jian Xia, Shuqing Kou, Yixin Zhang, Zhongbao Jian
Summary: In this study, a cooperative strategy combining the concerted double-layer steric strategy with the rotation-restricted strategy was applied to the newly prepared alpha-diimine nickel catalysts. These catalysts exhibited enhanced molecular weight in ethylene polymerization compared to freely rotated ones. Moreover, the preferred nickel catalyst had the ability to produce virtually linear polyethylene with ultra-high molecular weight and catalytic activity.
Article
Polymer Science
Quan Wang, Wenbing Wang, Weicheng Qu, Wenmin Pang, Muhammad Qasim, Chen Zou
Summary: This study successfully synthesized two novel cationic nickel catalysts and supported them on solid supports to prepare heterogeneous catalysts. These catalysts showed high activity and thermal stability in ethylene polymerization, with significantly improved polymerization parameters. Moreover, these catalysts also enabled copolymerization of ethylene with a series of polar comonomers.
JOURNAL OF POLYMER SCIENCE
(2023)
Article
Chemistry, Applied
Qiuyue Zhang, Ming Liu, Yanping Ma, Zhibin Ye, Tongling Liang, Wen-Hua Sun
Summary: A series of nickel bromide complexes containing rigid bidentate bis(arylimino)camphane ligands have been synthesized and characterized. These complexes exhibit good catalytic activity and thermal stability in ethylene polymerization, producing high molecular weight polyethylenes. The branching content and type of the resulting polyethylenes are influenced by the N-aryl substituents in the ligands.
APPLIED ORGANOMETALLIC CHEMISTRY
(2022)
Article
Polymer Science
Fan Yu, Pei Li, Mengli Xu, Guoyong Xu, Yinna Na, Shaojie Zhang, Fuzhou Wang, Chen Tan
Summary: This study investigated the influence of polyethylene glycol unit on nickel-catalyzed ethylene polymerization, finding that the molecular weight of products increased with the number of oxygen atoms on the polyethylene glycol unit. The introduction of MgCl2 support resulted in higher molecular weights and lower branch densities of polymers, with heterogeneous polymerizations generating polymers with excellent powder morphology.
Article
Chemistry, Multidisciplinary
Zhanshan Ma, Mengli Xu, Ningning Zhu, Chen Tan, Changle Chen
Summary: Heterogenization can improve the thermal stability and product morphology control of olefin polymerization catalysts, which are important parameters for industrial polyethylene production. In this study, alpha-diimine nickel catalysts with -OH or -ONa anchoring groups were designed and prepared to enable facile heterogenization on silica. The heterogeneous catalysts exhibited enhanced thermal stabilities and high catalytic activity, resulting in improvements in polymer morphology control, catalytic activity, and polyethylene molecular weight.
CHINESE JOURNAL OF CHEMISTRY
(2023)
Article
Polymer Science
Qiankun Li, Hongliang Mu, Zhongbao Jian
Summary: A new family of neutral salicylaldiminato nickel(II) catalysts (Ni1-Ni5) with well designed ortho substituents to the phenoxy moiety is developed, showing moderate to high activity for ethylene polymerization. By using these catalysts, polyethylene materials with lower molecular weight and significantly higher branching degree can be obtained, facilitating the synthesis of various polyethylene products ranging from solid plastic to wax and oil. The upgraded catalysts Ni6 and Ni7 produce polymers with high molecular weight and high branching degree, resulting in polyethylenes with excellent elastic properties.
Article
Polymer Science
Dan Peng, Menghe Xu, Chen Tan, Changle Chen
Summary: In this study, an emulsion polymerization strategy was used to heterogenize imino-based nickel olefin polymerization catalysts on solid supports. Polymeric microspheres were prepared through emulsion copolymerization, and the resulting heterogeneous nickel catalysts exhibited excellent properties in ethylene polymerization and copolymerization. The catalytic properties could be controlled by adjusting the comonomer type, composition, and particle size. This strategy allowed for product morphology control, avoided reactor fouling, and generated polyethylene products with minimal inorganic contamination. Furthermore, the introduction of polymer microspheres improved the mechanical and surface properties of polyolefin products.
Article
Chemistry, Inorganic & Nuclear
Yan-Bing Wang, Chenlong Nan, Weize Zhuo, Chen Zou, Hui Jiang, Xin-Qi Hao, Changle Chen, Mao-Ping Song
Summary: The introduction of O-donor groups on amine-imine ligands leads to the synthesis of a series of nickel complexes, which exhibit high catalytic activities and produce polyethylene elastomers with high molecular weight. Moreover, these nickel complexes can also catalyze the copolymerization of ethylene with various functional monomers to prepare functionalized polyolefins.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Xu-ling Wang, Yan-ping Zhang, Fei Wang, Li Pan, Bin Wang, Yue-sheng Li
Summary: A series of methyl nickel complexes with phosphino-naphtholate chelate ligands have been designed and synthesized with high activity towards ethylene polymerization and ethylene/unsaturated acid ester copolymerization. These catalysts show outstanding catalytic activities, achieving high productivity in both ethylene polymerization and ethylene/methyl acrylate copolymerization.
Article
Chemistry, Applied
Jie Wu, Pei Li, Juan Zhang, Zhengquan Dong, Wu Li, Muhammad Sohail Bashir, Yougui Li, Fuzhou Wang
Summary: A class of nickel (II) complexes with variable electronic nature were synthesized and characterized. X-ray crystallography analysis showed that these complexes have a distorted tetrahedral geometry and can be used for chain-walking polymerization to obtain highly active and high molecular weight branched polymers.
APPLIED ORGANOMETALLIC CHEMISTRY
(2023)
Article
Polymer Science
Jie Dong, Baiquan Wang
Summary: In this study, a series of tridentate imidazo[1,5-alquinolin-9-olate-1-ylidene (IZOQ) palladium catalysts with dimethylaminoethyl were synthesized and showed high catalytic activity and thermal stability in the homo- and copolymerization of norbornene with polar monomers. The rigid annulated backbone significantly enhanced the activities of these complexes, while electron-withdrawing groups at the annulated backbone positively affected the (co)polymerization activity.
Article
Chemistry, Multidisciplinary
Quan Wang, Zhao Zhang, Chen Zou, Changle Chen
Summary: In this study, a simple cocatalyst strategy was designed to enhance the catalytic properties of various nickel catalysts in ethylene polymerization and enable control over product morphology.
CHINESE CHEMICAL LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Fei Lin, Stefan Mecking
Summary: In this study, water-soluble synthetic transition metal catalysts were synthesized for olefin polymerization. The nickel catalysts with hydrophilic active sites demonstrated high activity and produced high molecular weight polyethylene in aqueous conditions, even at elevated temperatures.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Polymer Science
Benjamin A. Paren, Manuel Haeussler, Patrick Rathenow, Stefan Mecking, Karen Winey
Summary: We have presented a set of sulfonated monodisperse telechelic polyethylene ionomers that demonstrate ion transport of metal cations in layered ionic assemblies. These polymers have well-defined structures and exhibit different crystal packing and ion transport properties at different temperatures.
Article
Chemistry, Multidisciplinary
Jinseok Park, Anne Staiger, Stefan Mecking, Karen I. Winey
Summary: This study demonstrates that ionic functionality in a multiblock architecture can produce highly ordered nanostructures in thin films, including bicontinuous double gyroids. The researchers propose a versatile pathway to fabricating ordered nanostructures in thin films using ion-functionalized multiblock copolymers.
ACS CENTRAL SCIENCE
(2022)
Article
Chemistry, Multidisciplinary
Lukas Odenwald, Florian P. Wimmer, Nina K. Mast, Max G. Schussmann, Manfred Wilhelm, Stefan Mecking
Summary: Vitrimers combine the advantages of cross-linked materials with thermoplastic processability. Functionalized polyethylenes with cross-linkable groups were directly generated by catalytic insertion polymerization. These vitrimers exhibit excellent material properties and can be recycled due to reversible cross-linking.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Maria Voccia, Lukas Odenwald, Maximilian Baur, Fei Lin, Laura Falivene, Stefan Mecking, Lucia Caporaso
Summary: Polyethylene materials with in-chain-incorporated keto groups can be achieved by nonalternating copolymerization of ethylene with carbon monoxide using Ni(II) phosphinephenolate catalysts. The mechanism of this reaction involves the isomerization of an alkyl-olefin intermediate as the rate-determining step. The formation of non-alternating incorporation is influenced by ethylene binding, while the formation of alternating motifs is determined by the opening of the C,O-chelate. The crucial feature of these Ni(II) catalysts is the eta(2)-coordination of a P-bound aromatic moiety axially oriented to the metal center, which also affects the competition between the two pathways. The conformational constraints imposed in a 2',6'-dimethoxybiphenyl moiety result in disfavoring ethylene coordination along the alternating incorporation pathway, primarily governed by electronics, while not penalizing the nonalternating chain growth, primarily governed by sterics.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Amelie Fuchs, Stefan Mecking
Summary: This study reports an organometallic-mediated radical copolymerization method for carbon monoxide and ethylene, leading to the synthesis of keto-modified polyethylenes. The presence of carbon monoxide enhances the controlled character of the copolymerization by suppressing unfavorable termination pathways.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Polymer Science
Jinseok Park, Anne Staiger, Stefan Mecking, Karen Winey
Summary: Enhanced Li+ transport is demonstrated through selectively solvated ionic layers of a single-ion conducting polymer. The solvation of ionic domains with dimethyl sulfoxide (DMSO) accelerates structural relaxation and dissociation of ion pairs, leading to a significant enhancement of ion transport.
Article
Chemistry, Multidisciplinary
Marcel Eck, Simon Timm Schwab, Taylor Frederick Nelson, Katrin Wurst, Steffen Iberl, David Schleheck, Christoph Link, Glauco Battagliarin, Stefan Mecking
Summary: We have developed a new polyester material using biobased 1,18-octadecanedicarboxylic acid and ethylene glycol, which has a solid-state structure similar to polyethylene and comparable tensile properties to high density polyethylene (HDPE). Despite its crystallinity, high melting point and hydrophobic nature, the polyester-2,18 can be rapidly and completely hydrolytically degraded in vitro by naturally occurring enzymes. It also shows high biodegradability under industrial composting conditions and can be depolymerized by methanolysis for closed-loop recycling.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Stefanie de Roo, Felix Einsiedler, Stefan Mecking
Summary: This study demonstrates the catalytic conversion of renewable plant oils, including microalgae and waste oil, into industrially relevant alpha-olefins in the C-3 to C-10 regime. The biorefinery concept involves a catalytic sequence of ethenolysis, double bond isomerization, and subsequent ethenolysis, effectively rearranging the fatty acid chains into valuable chemical building blocks. Supercritical carbon dioxide (scCO(2)), a benign extraction and reaction solvent, is utilized.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Marcel Eck, Lea Bernabeu, Stefan Mecking
Summary: Researchers have developed a method to make PE-18,18 hydrolytically degradable by blending it with long-chain aliphatic poly(H-phosphonate)s. The blends exhibited similar properties to HDPE and showed complete hydrolysis of the poly(H-phosphonate)s component within four months under aqueous conditions. This hydrolysis led to embrittlement and fragmentation of the specimens, promoting eventual mineralization in the environment.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Maximilian Baur, Nina K. Mast, Jan P. Brahm, Rosa Habe, Tobias O. Morgen, Stefan Mecking
Summary: In this study, we modified polyethylene using both ketone and ester functional groups, and found that the simultaneous presence of both groups has no adverse effects on the crystal structure and thermal properties of polyethylene. Through oxidation of the in-chain ketone groups, high molecular weight polyethylenes with in-chain ketone-ester groups can be synthesized, which exhibit good photolytic degradation and chemical recyclability. We also demonstrated that polyethylenes bearing in-chain ketone groups can be produced via post-polymerization Baeyer-Villiger oxidation, combining the photodegradability of ketones with the chemical access point of esters.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Taylor F. Nelson, Dario Rothauer, Michael Sander, Stefan Mecking
Summary: Monomers sourced from waste or biomass, such as polyethylene waste or bio-based fatty acids, can be used to synthesize polyesters with various chain lengths. These polyesters exhibit high-density polyethylene-like properties, are ductile, and can be processed into films and fibers. They also show potential for chemical recycling or biodegradation in the environment.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Frieder Conradt, Vincent Bezold, Volker Wiechert, Steffen Huber, Stefan Mecking, Alfred Leitenstorfer, Ron Tenne
Summary: This study demonstrates the causal link between the quantum-confined Stark effect and spectral diffusion, and reveals the relation between the sensitivity of transition energy to an electric field and amplified spectral fluctuations. This is important for overcoming the critical barrier in applications of quantum sensing.
Article
Polymer Science
Stephanie F. Marxsen, Manuel Haeussler, Marcel Eck, Stefan Mecking, Rufina G. Alamo
Summary: In this study, the isothermal overall crystallization rates and linear growth rates of four symmetric long-spaced aliphatic polyesters were investigated. It was found that the polyesters exhibited discrete rate minima with increasing crystallization temperature, and the number and depth of these minima depended on the length of the methylene spacer between esters. The occurrence of rate minima could be explained by the self-poisoning feature and the difference in crystal thickness between non-integer and integer layered crystals.
Article
Chemistry, Multidisciplinary
Anne Saumer, Stefan Mecking
Summary: We report the synthesis and properties of ion-containing, long-chain aliphatic polyesters that can be degraded and fully recycled. These polyesters exhibit desirable traits, such as adhesion with polar compounds, due to the presence of ionic groups. The mechanical properties and melt rheology of these polyesters are significantly influenced by the nature of the cation counterions. Additionally, these polyesters can be chemically recycled by depolymerization. Our findings provide opportunities for tuning the properties of recyclable polyethylene-like polymers.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)