Following the goal to move chemical reactions toward more sustainable approaches, this work focuses on selective oxidative conversions of organic substrates. Inspired by the enzyme tyrosinase, a copper model complex was designed and synthesized. The ligand design was derived from previous research within this group, resulting in a dinucleating tridentate bis(pyrazolyl)methane ligand with an aromatic group as the bridging unit. Oxygenation of the corresponding Cu(I) precursor complex leads to the formation of a Cu2O2 species at room temperature. In addition to its catalytic activity towards selected phenolic substrates, this species exhibits remarkable stability towards temperature and water. Characterization via UV/Vis spectroscopy and mass spectrometry indicates the formation of a side-on & micro;-eta 2:eta 2-peroxido species. The exceptional stability of this Cu2O2 complex might pave the way for new and versatile applications of tyrosinase model complexes.

Research data management (RDM) is a key data literacy skill that chemistry students must acquire. Concepts such as the FAIR data principles (Findable, Accessible, Interoperable, Reusable) should be taught and applied in undergraduate studies already. Traditionally, research data from labs, theses, and internships were handwritten and stored in inaccessible formats such as PDFs, limiting reuse and machine learning applications. At RWTH Aachen University, a fifth-semester lab course introduces students to the electronic laboratory notebook (ELN) Chemotion, an open-source tool funded by the Deutsche Forschungsgemeinschaft (DFG) linked to the national NFDI4Chem initiative. Students plan, document, and evaluate experiments digitally, ensuring metadata and analysis are captured for long-term reuse. Chemotion’s intuitive interface and repository enable sustainable data sharing. To reinforce RDM, students receive a seminar and access to online training videos with interactive Moodle elements. Herein we highlight the use of the DALIA platform as a discovery tool for the students.

Polylactide (PLA) is one of the most promising bioplastics and is therefore often quoted as a solution to fight today's global plastics crisis. However, current PLA production via the ring-opening polymerization (ROP) of lactide is not yet sustainable since it heavily relies on the toxic catalyst tin octoate. To overcome the hurdles in scale-up and to accelerate the transition of promising new non-toxic alternative ROP catalysts from laboratory to industry, model-based analysis is a highly effective tool. Herein, our previously introduced kinetic model for the ROP of L-lactide using a non-toxic and robust Zn guanidine "asme"-type catalyst under industrially relevant melt conditions is expanded upon using two new co-initiators. The experimental data is evaluated using "traditional" kinetic analysis following pseudo-first-order kinetics to approximate a relationship between co-initiator concentration and the rate of polymerization. The range of validity of these findings is considerably expanded by taking model data into account to compare the performance of the different co-initiators in lactide ROP.

Tyrosinase is an oxygen‐activating enzyme and thus, functional model complexes are of high interest. The most prominent model complexes, the bis(µ‐oxido) as well as the µ‐η2:η2‐peroxido dicopper species, show catalytic activity toward phenolic substrates. Herein, we present a kinetic and mechanistic study of the electron transfer reaction of reducing agents with two bis(µ‐oxido) dicopper complexes. As ligands, the bis(guanidine) 2‐(2‐(((bis(dimethylamino)methylene)‐amino)methyl)‐phenyl)‐1,1,3,3‐tetramethylguanidine (TMG2tol) and the hybrid guanidine 2‐(3‐(dimethylamino)propyl)‐1,1,3,3‐tetramethylguanidine (TMGdmap) were chosen since previous studies showed that the dicopper species with these ligands are relatively stable at −80°C and at the same time have a fast formation. We determine full kinetic and thermodynamic parameters of the electron transfer reaction. With the help of spectroscopic kinetic analysis, we show that the electron transfer step is a reaction containing two independent steps. Moreover, density functional theory studies reveal the intriguing electronic structure of the reduced Cu2O2 complexes. This study highlights the ability of Cu2O2 species to cope with reducing equivalents.

The entatic state model system, the copper guanidinoquinoline complex pair [Cu(DMEGqu)2]+/2+, was herein studied regarding its photo-dynamics upon excitation. The photo-induced excited states of the copper(I) complex were investigated with time-resolved infrared and UV/Vis absorption spectroscopy, yielding the excited states' time constants upon metal-to-ligand charge transfer. Additional density functional theory calculations yield insights into the electronic structures of these excited states. The combined theoretical and experimental approach was used to construct the schematic reaction pathway of the excited states of [Cu(DMEGqu)2]PF6. Further, using a previous study of an entatic state model complex with a different guanidine moiety, [Cu(TMGqu)2]PF6, the substituents' effects on the complex cation's photo-dynamics were evaluated. The comparison shows that the less bulky and more rigid DMEG moiety measurably affects the charge transfer dynamics, underscoring the entatic state model as a potential tool for controlling copper photochemistry.

Analytical data in chemistry and other disciplines is usually generated in different formats and lacks common data and metadata standards that are necessary for a FAIR handling of research data. In the work presented herein, we describe a workflow that uses non-standardized, in some cases proprietary data formats from cyclic voltammetry measurements coming from individual devices as an instructive example, to yield open, standardized data that are annotated with rich metadata. The presented workflow includes concepts, software and infrastructure that can be used to support the whole data life cycle from the measurement of data to the publication of data and metadata in repositories. Components used for this workflow were made available as open source, allowing the re-use of this approach in other laboratories. The methods described for cyclic voltammetry can be adapted and used for other measurements and experimental data collections, allowing for an easy way to integrate new methods for digitalized research and FAIR data management.

As we navigate an increasingly data-driven world, advanced skills in using digital tools are mandatory to survive in day-to-day life. This digitalization has also found its way into chemical research, where more and more electronic research data are being generated. Handling and management of the collected data has become a considerable part of every researcher's daily work. Scientists need to be trained in these topics and concepts to apply them successfully in their research processes. To have the ability to effectively manage and utilize data, education in data literacy should start from the very beginning. However, research data topics are largely missing in chemistry curricular. Furthermore, students and researchers have a high demand for early education in research data management and handling and think that their institute would benefit if it were part of the official curriculum. The chemistry consortium in the national research data infrastructure in Germany NFDI4Chem tackles these challenges by providing several teaching and training courses and materials – for all career stages as well as all research data management (RDM) levels, e.g., workshops on research data management or electronic lab notebooks. As we believe that young chemists and students are key to the cultural change, we are increasingly paying attention to education, such as providing teaching courses, teaching materials, and knowledge bases. For comprehensive integration of RDM into chemistry curricular, the Study Commission of the German Chemical Society (Gesellschaft Deutscher Chemiker, GDCh) in-cluded data literacy in its recommendations for bachelor's degree programs in chemistry at universities in 2021. These guidelines support institutions in updating their curricular which is often a time-consuming procedure. Therefore, some lecturers which did not want to waste time for that process to conclude already introduced RDM topics in their courses where possi-ble. These leading examples, from institutions such as the RWTH Aachen University or RPTU Kaiserslautern-Landau, serve as best practice for others that are planning to integrate RDM teaching into their study programs. This presentation will highlight teaching programs from RWTH Aachen University that have been implemented in theoretical and practical student courses and the collected feedback of students thereof from several years. For example, the integration of RDM into an inorganic lab course serves as a hands-on experience where the students are required to use an electronic lab notebook to document their syntheses. Our approach of "subcurricular" integration into existing programs allowed a fast implementation into running chemistry lectures and avoided the major curricular changes mentioned above. Furthermore, similar educational efforts and institutional strategies from other institutions (e.g., RPTU Kaiserslautern-Landau, Friedrich Schiller University of Jena etc.) which were developed over the last years will be shown as well. Since these examples will also demonstrate differences among universities, we will in-troduce how and where we and others (can) openly share teaching materials for re-use to em-power others to adapt these curricular or subcurricular approaches for their individual institu-tions with minimal effort – not just for chemistry.

Results of scientific work in chemistry can usually be obtained in the form of materials and data. A big step towards transparency and reproducibility of the scientific work can be gained if scientists publish their data in research data repositories in a FAIR manner. Nevertheless, in order to make chemistry a sustainable discipline, obtaining FAIR data is insufficient and a comprehensive concept that includes preservation of materials is needed. In order to offer a comprehensive infrastructure to find and access data and materials that were generated in chemistry projects, we combined the infrastructure Chemotion repository with an archive for chemical compounds. Samples play a key role in this concept: we describe how FAIR metadata of a virtual sample representation can be used to refer to a physically available sample in a materials’ archive and to link it with the FAIR research data gained using the said sample. We further describe the measures to make the physically available samples not only FAIR through their metadata but also findable, accessible and reusable.

In this study, two new hybrid guanidine ligands are presented that serve as the basis for the preparation of six new zinc-hybrid guanidine complexes. The complex [Zn{(R,R)TMGNMe2(1,2)ch}2](OTf)2 (C1) shows a very high catalytic activity toward lactide and caprolactone ring-opening polymerization (ROP) under industrially relevant bulk conditions. Using recrystallized l-lactide, polylactide with a molar mass of up to 118 000 g mol-1 can be produced. The extremely fast caprolactone polymerization highlights the versatility of C1, as the polymerization rate constants are of the same order of magnitude. This is further underlined by high activity toward the chemical recycling of polyesters. In particular, C1 can be recycled highly efficiently, performing methanolysis and ethanolysis of polylactide up to nine times without any loss of activity. By combining efficient polymerization and depolymerization of (bio)polyesters, new catalyst paves the way toward a circular plastics economy.

As we navigate an increasingly data-driven world, advanced skills in using digital tools are mandatory to survive in day-to-day life. This digitalization has also found its way into chemical research, where more and more electronic research data are being generated. Handling and management of the collected data has become a considerable part of every researcher's daily work. Scientists need to be trained in these topics and concepts to apply them successfully in their research processes. To have the ability to effectively manage and utilize data, education in data literacy should start from the very beginning. However, research data topics are largely missing in chemistry curricular. Furthermore, students and researchers have a high demand for early education in research data management and handling and think that their institute would benefit if it were part of the official curriculum. The chemistry consortium in the national research data infrastructure in Germany NFDI4Chem tackles these challenges by providing several teaching and training courses and materials – for all career stages as well as all research data management (RDM) levels, e.g., workshops on research data management or electronic lab notebooks. As we believe that young chemists and students are key to the cultural change, we are increasingly paying attention to education, such as providing teaching courses, teaching materials, and knowledge bases. For comprehensive integration of RDM into chemistry curricular, the Study Commission of the German Chemical Society (Gesellschaft Deutscher Chemiker, GDCh) in-cluded data literacy in its recommendations for bachelor's degree programs in chemistry at universities in 2021. These guidelines support institutions in updating their curricular which is often a time-consuming procedure. Therefore, some lecturers which did not want to waste time for that process to conclude already introduced RDM topics in their courses where possi-ble. These leading examples, from institutions such as the RWTH Aachen University or RPTU Kaiserslautern-Landau, serve as best practice for others that are planning to integrate RDM teaching into their study programs. This presentation will highlight teaching programs from RWTH Aachen University that have been implemented in theoretical and practical student courses and the collected feedback of students thereof from several years. For example, the integration of RDM into an inorganic lab course serves as a hands-on experience where the students are required to use an electronic lab notebook to document their syntheses. Our approach of "subcurricular" integration into existing programs allowed a fast implementation into running chemistry lectures and avoided the major curricular changes mentioned above. Furthermore, similar educational efforts and institutional strategies from other institutions (e.g., RPTU Kaiserslautern-Landau, Friedrich Schiller University of Jena etc.) which were developed over the last years will be shown as well. Since these examples will also demonstrate differences among universities, we will in-troduce how and where we and others (can) openly share teaching materials for re-use to em-power others to adapt these curricular or subcurricular approaches for their individual institu-tions with minimal effort – not just for chemistry.

With 300 billion tons available in the biosphere, lignin is the second most abundant biopolymer on Earth. However, less than two percent is used for value‐added applications. One potential application is the use of lignin as a building block for thermoplastics. The majority of plastics today are made from fossil‐based feedstocks. Therefore, the use of lignin can counteract the increasingly scarce petroleum resources. A highly useful approach is the copolymerization with cyclic lactones such as caprolactone (CL) via ring‐opening polymerization (ROP). The synthesis of lignin‐polycaprolactone (PCL) copolymers can help to combine the beneficial properties of PCL and lignin to create potential new applications. In this work, lignin‐PCL copolymers are synthesized in a sustainable approach using the nontoxic, highly active, and robust zinc‐based guanidine catalyst [Zn{( R,R )‐DMEG 2 (1,2)ch} 2 ]OTf 2 · THF. Analyzing the reaction kinetics, it was found that the pseudo‐first order reaction kinetics do not proceed with a uniform rate constant over the entire reaction. An acceleration occurs after the initial formation of PCL chains at the lignin core, with reaction rates depending on both the catalyst and lignin content. These new findings contribute to the mechanistic understanding behind lignin functionalization, highlighting the potential of such bio‐based copolymers for a sustainable plastic use.

In this study, the aliphatic N,N-bisguanidine zinc complex [Zn(DMEG2ch)2](OTf)2 ⋅ THF is introduced as a promising candidate for the chemical recycling of (bio) polyesters. This catalyst is highly active in the ring-opening polymerization (ROP) of lactide (LA) and ϵ-caprolactone (CL). The combination of polymerization and depolymerization activity creates new pathways towards a sustainable circular economy. The catalytic activity of [Zn(DMEG2ch)2](OTf)2 ⋅ THF for the chemical recycling of polylactide (PLA) via alcoholysis was investigated by detailed kinetic and thermodynamic studies. It is shown that various high value-added alkyl lactates can be obtained efficiently under mild reaction conditions. Catalyst recycling was successfully tested using ethanol for the degradation of PLA. In addition, LA can be recovered directly from PLA, enabling either open- or closed-loop recycling. Selective PLA degradation from mixtures with polyethylene terephthalate (PET) and polymer blends are presented. For the first time, a cascade recycling reaction of a PLA/polycaprolactone (PCL) blend is tested with a zinc-based bisguanidine catalyst, whereby PLA is degraded selectively at first and subsequent modification of the reaction conditions leads to efficient degradation of the remaining PCL. The highly active, universally applicable benign zinc catalyst allows the implementation of a circular plastics economy and thus the reduction of plastic pollution in the environment.

In a previous study, we showed that the properties and the ability as an entatic state model of copper guanidine quinoline complexes are significantly influenced by a methyl or methyl ester substituent in the 2-position. To prove the importance of the 2-position of the substituent, two novel guanidine quinoline ligands with a methyl or methyl ester substituent in the 4-position and the corresponding copper complexes were synthesized and characterized in this study. The influence of the substituent position on the copper complexes was investigated with various experimental and theoretical methods. The molecular structures of the copper complexes were examined in the solid state by single-crystal X-ray diffraction (SCXRD) and by density functional theory (DFT) calculations indicating a strong dependency on the substituent position compared to the systems substituted in the 2-position from the previous study. Further, the significantly different influence on the donor properties in dependency on the substituent position was analyzed with natural bond orbital (NBO) calculations. By the determination of the redox potentials, the impact on the electrochemical stabilization was examined. With regard to further previously analyzed guanidine quinoline copper complexes, the electrochemical stabilization was correlated with the charge-transfer energies calculated by NBO analysis and ground state energies, revealing the substituent influence and enabling a comparatively easy and accurate possibility for the theoretical calculation of the relative redox potential. Finally, the electron transfer properties were quantified by determining the electron self-exchange rates via the Marcus theory and by theoretical calculation of the reorganization energies via Nelsen's four-point method. The results gave important insights into the dependency between the ability of the copper complexes as entatic state model and the type and position of the substituent.

We report the syntheses of tin(II) salts of the types [L1SnX]SnX3 [L1=2,6-{(i-PrO)2(O)P}2C5H3N: 1, X=Cl; 2, X=Br], [L2SnCl]SnCl3 [L2=2-{(i-PrO)Ph(O)P}-6-{(i-PrO)2(O)P}C5H3N: 3], [L3SnX]SnX3 [L3=2,6-{MeO(O)C}2C5H3N: 4, X=Cl; 5, X=Br], [L4SnX]SnX3 [L4=2,6-{Et2N(O)C}2C5H3N: 6, X=Cl; 7, X=Br]. These compounds were obtained by addition of SnX2 to the corresponding ligand inducing autoionization of the respective tin(II) halide. The thermal stability of 1, 3, and 4 was elucidated, giving, under ester cleavage and cyclisation, the tin(II) derivatives 8-12. The reaction of [L1SnCl]SnCl3 (1) with W(CO)4(thf)2 afforded the tungsten tetracarbonyl complex [{L1SnCl}{SnCl3}W(CO)4] (13), representing the first example in which a tin(II) stannate anion and a tin(II) stannylium cation simultaneously coordinate to a transition metal centre. The compounds were characterized by single crystal X-ray diffraction analyses and in part by elemental analyses, IR and NMR spectroscopy, electrospray ionization mass spectrometry. DFT calculations accompany the experimental work.

In the modern world, plastics have become indispensable. Due to their properties, they are used for a wide variety of applications ranging from packaging materials to textiles and medical technology. The vast majority of these plastics are made from finite fossil feedstocks that will need to be replaced in the long term to meet consumer demands in the future. Intensive research is being conducted into alternative bio‐based feedstocks to replace petroleum‐based plastics with more environmentally friendly variants. This includes polylactide, a polyester derived from lactic acid, which is mainly used as packaging material. In this work, star‐shaped copolymers consisting of polylactide and OrganoCat lignin with varying lignin loadings are synthesized using a “grafting‐from” approach directly from the lactide melt using a zinc‐based guanidine catalyst. This method proves to be efficient and copolymers can be produced after 30 min to three hours with high lactide conversions. Kinetic studies are performed to investigate the influence of different lignin loadings on the polymerization rate and 31P NMR experiments are used to analyze the functionalization of the lignin. Thermal analysis reveals an increase of the glass transition temperature and a higher thermal decomposition temperature with increasing lignin content.

Copper complexes of tripodal ligands have been used as model systems for electron transfer proteins for decades, displaying a broad range of electron self-exchange rates. We herein report a group of six tripodal tetradentate triarylamine ligands which display a varying number of guanidine and 2-methylquinolinyl moieties. Their corresponding Cu(I) complexes have been (re)synthesized and studied with regard to their electron transfer properties. While their molecular structures in the solid state are four-coordinate and display an uncommon umbrella distortion, DFT studies of the Cu(II) systems reveal that they gain an additional ligand in the form of a solvent molecule and exhibit a range of possible conformers that likely co-exist in thermal equilibrium. The redox-couples' electron self-exchange rates were analyzed using Marcus theory and vary over four orders of magnitude which cyclic voltammetry studies suggest to be due to a gated addition-oxidation electron transfer mechanism. This mechanism deviates from previously studied systems, likely due to the structural anomalies of the Cu(I) systems. This demonstrates that the chosen path of tripodal model systems can be influenced by molecular design.

Tripodal tetradentate N donor ligands stabilise the most active ATRP catalyst systems.

For in-depth research data management in chemistry, a cultural change is inevitable. To foster this change, future researchers need to be educated accordingly. The presentation will provide an overview of the first teaching approaches in student courses in chemistry at RWTH Aachen University. On the long range, the integration into curricular teaching is key to the cultural change.

In the field of bioplastics, complete kinetic models are rare but needed for industrial scale‐up. Herein, a complete kinetic model is developed to describe the behavior of robust and nontoxic guanidine carboxy Zn complexes in the lab‐scale ring opening polymerization (ROP) of l ‐lactide, mimicking industrial melt polymerization in the presence of a co‐initiator. The model includes inter‐ and intramolecular transesterification and random chain scission, considering the single site activity of the studied catalyst class, based upon the “asme”‐ligand already established in lactide ROP. This allows for the description of reaction rate constants and the prediction of conversion as well as molar mass and dispersity of the obtained polymer. It is further shown that the model can be applied to describe the same characteristics for the faster, next generation catalysts based on the archetype “asme” catalyst. This lays the foundation for a faster catalyst design, targeting the needs of industry in developing fast and nontoxic alternatives for the industrially used toxic ROP catalyst Sn octanoate, bridging the gap between academia and industry.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.