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The InChI (International Chemical Identifier) standard stands as a cornerstone in chemical informatics, facilitating the structure-based identification and exchange chemical information about compounds across various platforms and databases. The InChI as a unique canonical line notation has made chemical structures searchable on the internet at a broad scale. The largest repositories working with InChIs contain more than 1 billion structures. Central to the functionality of the InChI is its codebase, which orchestrates a series of intricate steps to generate unique identifiers for chemical compounds. Up to now, these steps have been sparsely documented and the InChI algorithm had to be seen as a black box. For the new v1.07 release, the code has been analyzed and the major steps documented, more than 3000 bugs and security issues, as well as nearly 60 Google OSSFuzz issues have been fixed. New test systems have been implemented that allow users to directly test the code developments. The move to GitHub has not only made the development more transparent but will also enable external contributors to join the further development of the InChI code. Motivation for this modernisation was the urgency to treat molecular inorganic compounds by the InChI in a meaningful way. Until now, no classic string representation fulfills this need of molecular inorganic chemistry. Currently bonds to metal centers are by definition disconnected which makes most inorganic InChIs meaningless at the moment. Herein, we propose new routines to remedy this problem in the representation of molecular inorganic compounds by the InChI. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Compartmentalization of homogeneous catalysts enhances their catalytic performance and can even increase the selectivity. Microgels can serve as smart catalyst carrier systems offering the compartmentalization combined with good accessibility of the catalyst enabling the recyclability and re‐usability. Yet, the incorporation of coordination complexes into microgels has not been studied systematically, lacking in detailed insight in their structure and catalytic performance. Herein, microgels are synthesized with controlled number and localization of copper(II)‐pyrazolyl‐complexes. The catalytic activity of microgels in the Henry reactions is examined showing significantly higher yields compared to pure copper(II)‐pyrazolyl‐complexes. Furthermore, the localization of the copper(II)‐pyrazolyl‐complexes in the microgel core resulted in higher product yields than for microgel catalysts with copper(II) complexes in the shell. Microgel catalysts are demonstrated with copper(II) complexes that can be used in numerous reaction cycles, allow re‐loading of copper to recover catalytically active centers, and can be applicable in industrially‐relevant catalytic processes. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The progress of the DFG-funded NFDI4Chem consortium (NFDI 4/1 - project number 441958208) in data management in chemistry is outlined in our latest report, highlighting the steps we have taken to integrate a data-centric approach within the chemistry community. This interim report offers a comprehensive overview of our data management activities, covering the reporting period from October 2020 to August 2023. The shift to digital tools in research documentation is driven by our work with Electronic Laboratory Notebooks (ELNs), such as Chemotion ELN, offering systematic data storage for easy retrieval and sharing. Additionally, we focus on developing repositories, such as Chemotion repository and RADAR4Chem , which fulfil the needs for the storage of chemical data. The NFDI4Chem Search Service ensures easy data access from our repositories. Our efforts extend to community engagement through conference visits and online presence, aimed at creating awareness for (digital) research data management and connecting to chemistry students and researchers. Our training programs have reached over 600 participants to date. Initiatives like the FAIR4Chem award and the Chemistry Data Days promote cultural change towards FAIR data. Our Editors4Chem initiative collaborates with publishers for standardised data management and the Ontologies4Chem workshops organised by our consortium promote the ontology development in the field. Apart from the consortium's engagement for chemists, NFDI4Chem members played key roles in the development of the NFDI as a whole. Being actively involved in the sections and task forces, NFDI4Chem promotes collaborative solutions across NFDI consortia. [ABSTRACT FROM AUTHOR]

Herein, we present electrochemical depolymerisation as a promising new technique for chemical recycling of polylactic acid. Using platinum electrodes and a current density of 50 mA cm−2, a maximum yield of 87% lactic acid was obtained. Moreover, first mechanistic insights, the effect of the reaction conditions, and application to real waste streams are discussed in the following. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]