Article
Biochemistry & Molecular Biology
Melanie Paul, Melissa Teubner, Benjamin Grimm-Lebsanft, Soeren Buchenau, Alexander Hoffmann, Michael Ruebhausen, Sonja Herres-Pawlis
Summary: The study describes the tyrosinase-like activity of hybrid guanidine-stabilized bis(mu-oxido) dicopper(III) complexes. Aromatic hybrid guanidine amine ligands with varying amine donor function were developed and their copper(I) complexes were analyzed for their ability to activate dioxygen. The resulting bis(mu-oxido) species showed remarkable activity in catalytic oxygenation reactions of polycyclic aromatic alcohols, while maintaining selectivity in the hydroxylation reactions of challenging phenolic substrates.
JOURNAL OF INORGANIC BIOCHEMISTRY
(2021)
Article
Polymer Science
Wiktor Bukowski, Agnieszka Bukowska, Aleksandra Sobota, Maciej Pytel, Karol Bester
Summary: The study investigated the effect of ligand structure on the catalytic activity of amine-bis(phenolate) chromium(III) complexes in the ring-opening copolymerization. Binary catalytic systems were found to be more active than complexes used individually, with DMAP proving to be the best co-catalyst choice.
Article
Chemistry, Inorganic & Nuclear
Bing-Feng Qian, Jun-Ling Wang, Ai-Quan Jia, Hua-Tian Shi, Qian-Feng Zhang
Summary: The synthesis, characterization, and photocatalytic properties of a series of cationic dinuclear Ru(III)-Ru(III) bis(mu-carboxylato) complexes formed by the reaction of [(Me3tacn)RuCl3•H2O] with substituted benzoic acid or phenylacetic acid, were investigated. The molecular structures of selected complexes were determined by single-crystal X-ray diffraction, and their electrochemical properties were also studied. Additionally, the photocatalytic hydrogen evolution performance of these complexes was evaluated in the paper.
INORGANICA CHIMICA ACTA
(2021)
Article
Chemistry, Multidisciplinary
Tristan Schuh, Olga Kataeva, Hans-Joachim Knoelker
Summary: We report the synthesis and X-ray crystal structure of mu-oxo-bis[(octacosafluoro-meso-tetraphenylporphyrinato)iron(iii)] [(FeTPPF28)(2)O]. This novel iron complex acts as an efficient catalyst for oxidative biaryl coupling reactions of diarylamines and carbazoles. The asymmetric oxidative coupling, in the presence of an axially chiral biaryl phosphoric acid as co-catalyst, provides 2,2'-bis(arylamino)-1,1'-biaryls with 96% ee. Additionally, the Wacker-type oxidation of alkenes to ketones with (FeTPPF28)(2)O as catalyst and phenylsilane as reductant proceeds at room temperature with air as the terminal oxidant, resulting in increased ketone/alcohol product ratios for internal and aliphatic alkenes.
Article
Chemistry, Physical
Peng Kang, Bo-Lin Lin, Tao A. G. Large, Jasper Ainsworth, Erik C. Wasinger, T. Daniel P. Stack
Summary: This study investigates the mechanism of exogenous phenolate ortho-hydroxylation by copper oxidants. The research finds that copper species with ligated phenolates formed through oxidation can catalyze the hydroxylation reaction of ortho-phenolates, generating products with ortho-substituents of C-H or C-X (Cl, Br). The study reveals the importance of electrophilic attack of the oxidized ligand into the π-system of the ligated phenolate.
FARADAY DISCUSSIONS
(2022)
Article
Chemistry, Inorganic & Nuclear
Feng Li, Jianghao He, Tingting Song, Wei Gao, Xiaoyue Mu, Ying Mu
Summary: A series of new zirconium complexes with bulkier ligands were synthesized and their catalytic performance in ethylene polymerization and copolymerization reactions was studied. The results showed that these complexes exhibited high catalytic activity and good comonomer incorporations, and displayed excellent catalytic performance under different activation conditions.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Inorganic & Nuclear
Lakshmi Suresh, Jone Finnstad, Karl W. Tornroos, Erwan Le Roux
Summary: Based on bis(phenolate)-functionalized N-heterocyclic carbene (NHC) ligands, oxo- and imido-vanadium(V) metal complexes were synthesized and structurally identified. The saturated NHC oxo-vanadium complexes were active in the coupling of CO2 and cyclohexene oxide, with the oxo-vanadium complex bearing the less electron-donating benzannulated NHC ligand showing higher activity in CHO conversion to PCHC. The saturated NHC imido-vanadium catalyst exhibited similar activity and selectivity as the analogous oxo-vanadium catalysts due to its reactivity with CO2 via a [2 + 2] cycloaddition reaction.
INORGANICA CHIMICA ACTA
(2021)
Article
Chemistry, Multidisciplinary
Yuanxin Cao, Juan A. Valdez-Moreira, Sam Hay, Jeremy M. Smith, Sam P. de Visser
Summary: In this study, a combination of experimental and computational methods was used to investigate biomimetic iron(IV)-oxo and iron(III)-oxo complexes. It was found that the second-coordination sphere significantly slows down the hydrogen atom abstraction reaction from toluene and the kinetics is zeroth order in substrate. However, the generated iron(II)-hydroxo has a low reduction potential, leading to unfavorability of OH rebound. On the other hand, the tolyl radical in solution reacts further with alternative reaction partners. In contrast, the iron(IV)-oxo species predominantly reacts through OH rebound to form alcohol products. The research highlights the importance of the metal oxidation state in determining reactivities and selectivities, suggesting that enzymes may require an iron(IV) center for efficient C-H hydroxylation reactions.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Polymer Science
Pip Catchpole, Rachel H. Platel
Summary: Poly(3-hydroxbutyrate-co-4-hydroxybutyrate) was successfully synthesized using a new type of catalyst, with varying degrees of success in terms of conversion rates and molecular weight control. The findings suggest limited control by the catalysts in terms of monomer selectivity and molecular weight regulation.
POLYMER INTERNATIONAL
(2022)
Article
Chemistry, Multidisciplinary
Debojyoti Mukherjee, Probal Nag, Albert A. Shteinman, Sivaranjana Reddy Vennapusa, Ujjwal Mandal, Mainak Mitra
Summary: A dinuclear copper(ii) complex has been synthesized and characterized, showing weak ferromagnetic interactions and high catecholase activity. A reaction mechanism has been proposed based on experimental findings.
Article
Chemistry, Multidisciplinary
Guojun Hu, Yanwei Wang, Yaorong Wang, Xuehua Zhu, Dan Yuan, Yingming Yao
Summary: Two amino-bridged bis(phenolate) neodymium complexes were synthesized and used as efficient initiators for the copolymerization of TMC and L-LA under mild conditions, resulting in the formation of random copolymers. NMR monitoring experiments confirmed the generation of a TMC/LA random copolymer through random copolymerization.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Ramona Jurgeleit, Benjamin Grimm-Lebsanft, Benedikt Maria Floeser, Melissa Teubner, Soren Buchenau, Laura Senft, Jonas Hoffmann, Maria Naumova, Christian Naether, Ivana Ivanovic-Burmazovic, Michael Ruebhausen, Felix Tuczek
Summary: The study demonstrates that low-temperature oxygenation of copper complexes results in the formation of unique tetranuclear mixed-valent peroxo compounds, which promote O-O bond homolysis and catalytic activity, showing efficient catalytic activity towards organic substrates.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Polymer Science
Feng Li, Yuhongxu Bai, Jianghao He, Tingting Song, Wei Gao, Xiaoyue Mu, Ying Mu
Summary: A series of novel Ti(IV) complexes with nonsymmetric amine-bis(phenolate) tetradentate ligands have been synthesized and characterized. These complexes exhibit moderate to high catalytic activities for ethylene polymerization and produce high molecular weight polyethylenes. They also show high catalytic activities for copolymerization reactions of propylene, 1-hexane, ethylene/1-hexene, and ethylene/1-octene, producing polyolefin thermoplastic elastomer or linear low-density polyethylene with high molecular weights and moderate to high comonomer incorporations.
Article
Chemistry, Physical
Wen-Bin Xie, Zhi Li
Summary: A series of chiral compounds were designed and synthesized for a highly enantioselective intramolecular hydroalkoxylation of nonactivated alkenes, resulting in the formation of 2-methylcoumarans with up to 99% yields and up to 97% enantiomeric excess under mild conditions.
Article
Chemistry, Inorganic & Nuclear
Yuki Kadoya, Machi Hata, Yoshiki Tanaka, Atsuhiro Hirohata, Yutaka Hitomi, Masahito Kodera
Summary: A series of new dicopper complexes of a p-cresol-2,6-bis(dpa) amide-tether ligand were synthesized, among which dicopper complex 2b exhibited remarkable cytotoxicity by rapidly cleaving DNA into linear form by activating H2O2 at neutral pH, as well as attacking the nucleolus and mitochondria.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Lukas Rasspe-Lange, Alexander Hoffmann, Christoph Gertig, Joshua Heck, Kai Leonhard, Sonja Herres-Pawlis
Summary: This study compares three different methods for the theoretical description of copper guanidine-quinoline complexes and evaluates their performance in predicting redox potentials.
JOURNAL OF COMPUTATIONAL CHEMISTRY
(2023)
Review
Chemistry, Multidisciplinary
Ruth D. Rittinghaus, Sonja Herres-Pawlis
Summary: Bioplastics, such as polylactide (PLA), offer a solution to environmental pollution and linear material flows as they can replace conventional plastics in various applications. The properties of PLA can be altered by introducing comonomers, including other lactones like epsilon-caprolactone (CL). However, controlling copolymerizations of lactide (LA) with other monomer classes remains challenging due to the complexity of the system. Catalysts play a crucial role in copolymerizations, determining the reaction kinetics and resulting microstructure. This review presents copolymerization catalysts for LA, categorized into catalysts for lactone block copolymers, lactone random copolymers, and multimechanistically synthesized copolymers.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Lisa Burkart, Alexander Eith, Alexander Hoffmann, Sonja Herres-Pawlis
Summary: This study evaluated a previously reported non-toxic guanidine-iron catalyst for its activity in the alcoholysis and aminolysis of polylactide (PLA). The results showed that the metal center of the catalyst has a significant impact on its activity. The study also expanded the scope of products from PLA waste by testing different nucleophiles. Overall, the catalyst showed promise for a circular (bio)plastics economy.
CHEMISTRY-AN ASIAN JOURNAL
(2023)
Article
Green & Sustainable Science & Technology
Niclas Conen, Martin Fuchs, Alexander Hoffmann, Sonja Herres-Pawlis, Andreas Jupke
Summary: A complete kinetic model has been developed to describe the behavior of guanidine carboxy Zn complexes in the lab-scale ring opening polymerization. The model can predict the conversion, molar mass, and dispersity of the obtained polymer, and can be applied to faster catalysts based on the archetype asme catalyst.
ADVANCED SUSTAINABLE SYSTEMS
(2023)
Article
Chemistry, Physical
Wenjing Xu, Yingying Cheng, Jing Hou, Peng Kang
Summary: Reducing oxalic acid to glycolic acid electrochemically is difficult due to high overpotential, low selectivity, and low stability. This study presents mesoporous TiO2 spheres as catalysts for the reduction of oxalic acid to glycolic acid at low overpotential. The mesoporous structure increases the specific surface area and restricts the escape of intermediate glyoxalic acid, enabling deep reduction of oxalic acid to glycolic acid. The proposed mechanism suggests the important role of the Ti3+/Ti4+ redox pair in the reduction of oxalic acid.
Article
Chemistry, Multidisciplinary
Martin Fuchs, Pascal M. Schaefer, Wolf Wagner, Ian Krumm, Marcel Walbeck, Regina Dietrich, Alexander Hoffmann, Sonja Herres-Pawlis
Summary: Here, a new aliphatic hybrid guanidine N,O-donor ligand (TMGeech) and its zinc chloride complex ([ZnCl2(TMGeech)]) are introduced. The complex shows high catalytic activity for the ring-opening polymerization (ROP) of lactide in toluene, surpassing the toxic industry standard tin octanoate by a factor of 10. The catalytic activity of [ZnCl2(TMGeech)] for the chemical recycling of polylactide (PLA) by alcoholysis in THF is investigated, demonstrating fast production of value-added lactates at mild temperatures.
Article
Chemistry, Inorganic & Nuclear
Jing Hou, Yingying Cheng, Hui Pan, Peng Kang
Summary: Direct electrochemical ammonia oxidation reaction (eAOR) is an efficient and sustainable strategy for wastewater treatment. A Ni(OH)2/SnO2 composite catalyst was synthesized and applied for eAOR. The catalyst exhibited high N2-N Faradaic efficiency and current density, with the promotion of Sn to ammonia absorption and suppression of oxygen evolution reaction.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Nicole A. Parks, Tillmann G. Fischer, Claudia Blankenburg, Vincent F. Scalfani, Leah R. McEwen, Sonja Herres-Pawlis, Steffen Neumann
Summary: Journals play a crucial role in shaping community behavior through communicating research results. Publishing research data alongside journal articles is considered good practice. This article analyzes author guidelines from various publishers and journals in the field of chemistry and identifies areas for improvement in supporting different criteria.
PURE AND APPLIED CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Tao Yan, Hui Pan, Zhikun Liu, Peng Kang
Summary: A 3D porous electrode (TDPE) is prepared by a simple phase inversion method, enabling electrochemical reduction of CO2 to formic acid (FA) in acidic conditions. TDPE with interconnected channels, high porosity, and suitable wettability improves mass transport and creates a higher local pH micro-environment for CO2 reduction compared to other electrode designs. The proton transfer is identified as the rate-determining step at pH 1.8, while not significant in neutral solution, indicating that protons aid the overall kinetics. FA Faradaic efficiency of 89.2% is achieved at pH 2.7 in a flow cell, producing a concentration of 0.1 m. The integration of catalyst and gas-liquid partition layer into a single electrode structure by the phase inversion method provides a facile approach for direct production of FA through electrochemical CO2 reduction.
Article
Chemistry, Physical
Yingying Cheng, Wenjing Xu, Jing Hou, Peng Kang
Summary: Electrosynthesis of multi-carbon chemicals from oxalic acid offers a sustainable pathway for chemical production. A series of gallium tin oxide catalysts were used for selective electroreduction of oxalic acid to glyoxylic acid and glycolic acid. The product distribution can be controlled by adjusting the reaction temperature, and the catalysts showed high efficiency and stability in acidic media.
Article
Chemistry, Multidisciplinary
Xiaomei Yuan, Tao Yan, Zhikun Liu, Peng Kang
Summary: Alkaline water electrolysis is a promising technology for green hydrogen production. In this study, zirconia-based composite membranes were constructed using alkanolamine-modified zirconia particles synthesized by a one-pot method. The diethanolamine (DEA)-functionalized zirconia separator showed superior hydrophilicity and low resistance compared to a commercial separator. It also exhibited high electrochemical performance and stability, closing the gap with proton exchange membrane electrolysis.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)
Review
Multidisciplinary Sciences
Ali Abdelshafy, Alina Hermann, Sonja Herres-Pawlis, Grit Walther
Summary: The aim of this study is to comprehensively analyze the production and recycling processes, carbon footprint, and prices of PLA, as well as to investigate second-generation PLA production from technical, economic, and ecological perspectives simultaneously. The German Federal State of North Rhine-Westphalia (NRW) is chosen as a region of interest, and the study quantifies and illustrates the locations of different suitable second-generation feedstocks in the region. However, there are various obstacles that may challenge the identified potentials, such as high demand for bioresources, feedstock quality, spatial aspects, and logistics.
Article
Chemistry, Analytical
Jing Cui, Jing Hou, Hui Pan, Peng Kang
Summary: This study synthesized self-supported CuM (M = Ni, Fe, Co) carbon cloth electrodes via hydrothermal synthesis and investigated their performance in electrochemical ammonia oxidation reaction (eAOR). The CuCo/CC electrode with the optimal Cu/Co ratio of 1:2 achieved a dinitrogen selectivity of 90.0% and Faraday efficiency of 77.4% after three hours of electrolysis at 1.65 V vs. RHE. The reaction mechanism was explored using Raman and in-situ IR spectroscopy, revealing that Cu acts as NH3 adsorption sites and Co catalyzes the oxidation, leading to high efficiency.
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
(2023)
Article
Chemistry, Physical
Christian Conrads, Lisa Burkart, Sven Soerensen, Sandra Noichl, Yasemin Kara, Joshua Heck, Alexander Hoffmann, Sonja Herres-Pawlis
Summary: This study presents eight novel iron(ii) chloride complexes and investigates their activity in the synthesis of polylactide. The results show that iron guanidines with simple ligands demonstrate a high level of catalytic activity and stability, suggesting great potential for industrial applications.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Fabian Fink, Henrika M. Hueppe, Nicole Jung, Alexander Hoffmann, Sonja Herres-Pawlis
Summary: The documentation and storage of experimental data are essential in research data management and science. Collecting and sharing machine-readable data, including negative results, is a crucial step in automated data curation and data generation for machine learning processes. The electronic laboratory notebook, Chemotion, enables the sharing of synthesis data with other scientists while considering these aspects.