Article
Chemistry, Multidisciplinary
Mateusz Janeta, Julius X. Heidlas, Olafs Daugulis, Maurice Brookhart
Summary: The reactivity of Ni-II and Pd-II olefin polymerization catalysts can be enhanced by introducing electron-withdrawing substituents on the supporting ligands, as demonstrated in this paper. Compared to the trifluoromethyl group, the trippy substituent shows stronger electron-withdrawing ability, leading to better performance in catalytic turnover frequency and polymer molecular weight.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Yu Zhu, Peng Wu, Senyao Liu, Jieyu Yang, Fapu Wu, Wenwen Cao, Yuexia Yang, Bingbing Zheng, Hu Xiong
Summary: This study presents a strategy for constructing highly bright J-aggregates with enhanced NIR-II fluorescence by introducing electron-withdrawing substituents. The study demonstrates the successful conversion of various dye skeletons into J-aggregates with improved fluorescence properties, offering great potential for applications in bioimaging, encryption, and information storage.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(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
Chemistry, Multidisciplinary
Fei Lin, Tobias O. Morgen, Stefan Mecking
Summary: P,O-chelated Ni(II) complexes typically result in low molecular weight polymers or oligomers due to competitive chain transfer events. However, bulky substituted phosphinophenolato Ni(II) complexes have shown the ability to polymerize in a living fashion without chain transfer, leading to high molecular weight polyethylenes in aqueous nanoparticle dispersions. The catalyst demonstrates stability and activity up to 70 degrees Celsius in water.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Applied
Jiyoung Hwang, T. Sheshashena Reddy, Hyungkyu Moon, Hae Dong Lee, Myung-Seok Choi
Summary: In this study, dicyanovinylporphyrins (DCVPs) 2a to 2d were synthesized and used as fluorescent sensors for cyanide (CN-) detection. The reactivity of DCVPs to CN- was controlled by introducing electron-donating or electron-withdrawing groups. The sensing abilities of DCVPs for various anions were studied, and it was found that DCVPs exhibited selective reduction in fluorescence intensity upon the addition of CN- ions. DCVP 2d showed strong detection capabilities for CN- ions, with a detection limit of 3.14 x 10-8 M in THF.
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
Materials Science, Multidisciplinary
Si Liu, Lei Zheng, Mingxi Chen, Yajing Sun, Peng Wang, Shuyu Li, Hongnan Wu, Xiaotao Zhang, Wenping Hu
Summary: Three anthracene derivatives with varying electron-withdrawing substituents were designed and synthesized to investigate their molecular packing structure and photoelectric properties. As the electron-withdrawing abilities increased, the intermolecular interactions deteriorated and photoelectric properties worsened. This suggests a potential strategy for fabricating n-type anthracene derivative semiconductor materials.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
Article
Polymer Science
Li Zhou, Chong-Long Li, Run-Tan Gao, Shu-Ming Kang, Lei Xu, Xun-Hui Xu, Na Liu, Zong-Quan Wu
Summary: The facile synthesis of high optically active helical polymers from achiral monomers is still a challenge. Chiral Ni(II) catalysts were prepared to efficiently initiate living/controlled polymerization of allene monomers, exhibiting interesting regioselectivity and helix-sense selectivity. The resulting polyallenes showed high optical activity, solely determined by the chirality of the Ni(II) catalysts.
Article
Spectroscopy
Lu Chen, Haixiang He, Xindi Huang, Honghong Xu, Yan Yu
Summary: In this study, the fluorescence mechanism of (E)-4-(3-(benzo[d]thiazol-2-yl)-2-hydroxy-5-methylstyryl)-1-methylpyridin-1-ium (HBTMY) and the excited-state intramolecular proton transfer process (ESIPT) of hydroxyphenyl were investigated using density functional theory (DFT) and time-dependent density functional theory (TDDFT). The effects of electron-donating and electron-withdrawing groups on the fluorescence and the ESIPT process were studied by introducing different substituents into HBTMY. The results provide guidance for cell imaging and strategies to adjust and control fluorescence by introducing substituents.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2023)
Article
Chemistry, Multidisciplinary
Eva Schiebel, Maria Voccia, Laura Falivene, Inigo Gottker-Schnetmann, Lucia Caporaso, Stefan Mecking
Summary: The cyclophane structure can control steric pressure in metal catalysts, leading to improved efficiency and stability in ethylene polymerization.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Polymer Science
Fei Wang, Li Pan, Vladislav A. Tuskaev, Svetlana Ch. Gagieva, Yue-Sheng Li
Summary: This study develops a nickel-based catalyst for the efficient copolymerization of olefin with polar monomers, which has been a longstanding challenge in the field.
CHINESE JOURNAL OF POLYMER SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Chaoqun Wang, Xiaohui Kang, Shengyu Dai, Fengchao Cui, Yunqi Li, Hongliang Mu, Stefan Mecking, Zhongbao Jian
Summary: An effective shielding strategy using dibenzosuberyl groups achieves protection of both apical positions of a neutral Ni-II active site, suppressing chain transfer and branch formation to produce ultrahigh molecular weight polyethylenes with a strictly linear microstructure. Key features of the catalyst include easy preparation, thermal robustness, living polymerization ability, and compatibility with THF as a polar reaction medium.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Yao Sun, Quan Wang, Yao Pan, Wenmin Pang, Chen Zou, Min Chen
Summary: In this study, immobilized nickel/iron catalysts with imine ligands were successfully designed and applied in high-activity and high-thermal stability ethylene polymerization. The SiO2-supported catalysts exhibited better performance compared to their homogeneous counterparts, showing no reactor fouling and excellent control of polymer morphology. Moreover, the immobilized nickel catalysts showed higher tolerance towards polar monomers and achieved efficient copolymerization with high activity and incorporation ratio.
CHINESE JOURNAL OF CHEMISTRY
(2022)
Article
Chemistry, Inorganic & Nuclear
Ningning Zhu, Tao Liang, Yongshuang Huang, Wenmin Pang, Min Chen, Chen Tan
Summary: Phosphinecarbonylpalladium and -nickel catalysts with various substituents on the ligand backbone exhibited high activities and molecular weights in both ethylene polymerization and copolymerization with polar monomers. The electron-donating group and cyclic backbone structure can impact catalytic activities and polymer molecular weights. Installation of a pyridyl moiety in the ligand backbone enhances catalytic activities and responsiveness to Lewis acids.
INORGANIC CHEMISTRY
(2021)
Article
Polymer Science
Dan Peng, Hailong He, Wenmin Pang, Shabnam Behzadi, Muhammad Qasim
Summary: It is fascinating to use nickel based neutral P<^>O type catalysts to prepare polyethylene with ultra-high molecular weight under homogeneous conditions. This contribution explores the ligand remote electronic effect in sterically hindered phosphine-phenolate based neutral nickel catalysts Ni1-Ni3 to produce UHMWPE. The maximal activity of these catalysts was found to be 1.33 x 106 g mol-1 h-1, indicating their high reactivity. The nickel catalysts show good thermal stability at a high temperature of 120 degrees C. Moreover, all these catalysts are capable of generating UHMWPE with a maximum Mn of 2.51 x 106 g mol-1 by Ni2, which is attributed to the effective shield provided by the minimum distance between the Ni center and the oxygen atom in Ni1 and the steric remote substituents effect.
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
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
Natalie S. Schunck, Stefan Mecking
Summary: Sustainable sources are crucial for chemicals production, and microalgae have the potential to catalytically convert renewable substrates inside living cells, generating valuable building blocks for chemical production.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Polymer Science
Maximilian Baur, Stefan Mecking
Summary: Linear polyethylenes with incorporated in-chain keto and side-chain ester groups are formed by Ni(II)-catalyzed terpolymerization of ethylene, carbon monoxide, and methyl acrylate. These polymers possess a random structure while retaining the solid-state structure of polyethylene.
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)
