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To aid valorisation of beer brewing by-products, more insight into their composition is essential. We have analysed the phenolic compound composition of four brewing by-products, namely barley rootlets, spent grain, hot trub, and cold trub. The main phenolics detected were hydroxycinnamoylagmatines and dimers thereof. Barley rootlets contained the highest hydroxycinnamoylagmatine content and cold trub the highest dimer content. Additionally, variations in (dimeric) hydroxycinnamoylagmatine composition and content were observed in fourteen barley rootlet samples. The most abundant compound in all rootlets was the glycosylated 4-O-7′/3-8′-linked heterodimer of coumaroylagmatine and feruloylagmatine, i.e. CouAgm-4-O-7′/3-8′-(4′Hex)-DFerAgm. Structures of glycosylated and hydroxylated derivatives of coumaroylagmatine were elucidated by NMR spectroscopy after their purification from a rootlet extract. An MS-based decision tree was developed, which aids in identifying hydroxycinnamoylagmatine dimers in complex mixtures. In conclusion, this study shows that the diversity of phenolamides and (neo)lignanamides in barley-derived by-products is larger than previously reported.

Proton NMR is the fastest and most straightforward of all NMR experimental designs. Unfortunately, it suffers from lengthy annotation times and does not always have a clear and unbiased interpretation. Introducing an automatic procedure for the analysis of NMR data that can ease the chemical compounds characterization while ensuring consistency of the results across the scientific community is still an open challenge. Recently, we introduced a supervised deep learning model that performs automated classification of signal regions for their coupling pattern. Here we show how including uncertainty quantification in deep learning frameworks applied to NMR serves a dual-purpose of increasing the reliability of the prediction and detecting overlapping multiplets.

Accurate extraction of multiplet parameters, such as J-couplings and chemical shifts, play a vital role in small molecule analysis using nuclear magnetic resonance (NMR) spectroscopy. These parameters provide essential quantitative information about molecular structures, interatomic interactions, and chemical environments, enabling precise characterization of small organic compounds. This poster presents an innovative omputational approach that utilizes state-of-the-art deep learning techniques, specifically detection transformers, to automate and optimize the extraction of multiplet parameters from 1D NMR spectra of small molecules. By incorporating these advanced computational methods, experimenters can achieve improved efficiency, accuracy, and speed in analyzing and characterizing small organic compounds using NMR spectroscopy.

Bandgap-tuneable mixed-halide 3D perovskites are of interest for multi-junction solar cells, but suffer from photoinduced spatial halide segregation. Mixed-halide 2D perovskites are more resistant to halide segregation and are promising coatings for 3D perovskite solar cells. The properties of mixed-halide compositions depend on the local halide distribution, which is challenging to study at the level of single octahedra. In particular, it has been suggested that there is a preference for occupation of the distinct axial and equatorial halide sites in mixed-halide 2D perovskites. 207Pb NMR can be used to probe the atomic-scale structure of lead-halide materials, but although the isotropic 207Pb shift is sensitive to halide stoichiometry, it cannot distinguish configurational isomers. Here, we use 2D isotropic–anisotropic correlation 207Pb NMR and relativistic DFT calculations to distinguish the [PbX6] configurations in mixed iodide–bromide 3D FAPb(Br1−xIx)3 perovskites and 2D BA2Pb(Br1−xIx)4 perovskites based on formamidinium (FA+) and butylammonium (BA+), respectively. We find that iodide preferentially occupies the axial site in BA-based 2D perovskites, which may explain the suppressed halide mobility.

The aggregation of amyloid peptides and proteins into toxic oligomers is a hallmark of neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, Machado-Joseph's disease, and transmissible spongiform encephalopathies. Inhibition of amyloid oligomers formation and interactions with biological counterparts, as well as the triggering of non-toxic amorphous aggregates, are strategies towards preventive interventions against these pathologies. NMR spectroscopy addresses the need for structural characterization of amyloid proteins and their aggregates, their binding to inhibitors, and rapid screening of compound libraries for ligand identification. Here we briefly discuss the solution experiments constituting the NMR spectroscopist‘s toolkit and provide examples of their application.

Water is known to play an important role for the crystallization and stability of Zr-based metal-organic frameworks (MOFs). This work investigates its effect on the vapor-assisted conversion (VAC) synthesis of UiO-67 MOF thin films on Au-coated Si substrates. We demonstrate the equilibration processes taking place during the VAC procedure, confirming the gradual equilibration of all solutions upon heating. The presence of water affects the vapor phase composition but does not significantly impact the acetic acid equilibration rate. However, the preparation of UiO-67 thin films by VAC is highly sensitive to the water content in the reaction. Some water is required for the formation of the zirconium clusters, but excessive water in the reaction vial yields poorly crystalline materials. Atmospheric water that is taken up by the vapor source can be sufficient to reduce crystallinity dramatically. This complication can be partially overcome by increasing the amount of acetic acid in the vapor source.

Water is known to play an important role for the crystallization and stability of Zr-based metal-organic frameworks (MOFs). This work investigates its effect on the vapor-assisted conversion (VAC) synthesis of UiO-67 MOF thin films on Au-coated Si substrates. We demonstrate the equilibration processes taking place during the VAC procedure, confirming the gradual equilibration of all solutions upon heating. The presence of water affects the vapor phase composition but does not significantly impact the acetic acid equilibration rate. However, the preparation of UiO-67 thin films by VAC is highly sensitive to the water content in the reaction. Some water is required for the formation of the zirconium clusters, but excessive water in the reaction vial yields poorly crystalline materials. Atmospheric water that is taken up by the vapor source can be sufficient to reduce crystallinity dramatically. This complication can be partially overcome by increasing the amount of acetic acid in the vapor source.

Carbohydrates are ubiquitous in nature and exhibit a multitude of roles. Besides nucleic and amino acids, they can be regarded as the third alphabet of life. They are used as energy source to fuel the cells, as structural building blocks and play a key role in cellular recognition processes. Compared to the other two groups of biomacromolecules, carbohydrates display a higher level of structural complexity by virtue of the number of individual monosaccharide building blocks, as well as the greater number of possibilities of connecting them and additional modifications. This renders a high information content and a good understanding of the structure-function relationship of glycans is important, since the presence or absence of specific structures can make the difference between health and disease. Carbohydrate structures can be characterized and studied by NMR spectroscopy at the atomic level. This process is time-consuming and error-prone, due to the narrow spectral window, in which most carbohydrate resonances are located leading to severe spectral overlap. Computer programs have been developed, aiding this process. This thesis investigates the quality of prediction of NMR chemical shifts of glycopeptides, highly branched oligosaccharide structures and those bearing a non-natural organic aglycone at the reducing end, as well as the automated determination of primary carbohydrate structures from unassigned NMR spectroscopic data thereof. Novel developments of the CASPER program are highlighted. The three-dimensional structure of carbohydrates plays an important role during carbohydrate-protein interactions. This thesis investigates the conformational preferences and dynamics of glycan structures ranging from di- to tetrasaccharides. A particular focus lies on the measurement of transglycosidic 3JCH coupling constants by NMR. Furthermore, the experimental spectroscopic data is compared to results from MD simulations. Synthetic carbohydrate chemistry has a strong fo

Water is known to play an important role for the crystallization and stability of Zr-based metal-organic frameworks (MOFs). This work investigates its effect on the vapor-assisted conversion (VAC) synthesis of UiO-67 MOF thin films on Au-coated Si substrates. We demonstrate the equilibration processes taking place during the VAC procedure, confirming the gradual equilibration of all solutions upon heating. The presence of water affects the vapor phase composition but does not significantly impact the acetic acid equilibration rate. However, the preparation of UiO-67 thin films by VAC is highly sensitive to the water content in the reaction. Some water is required for the formation of the zirconium clusters, but excessive water in the reaction vial yields poorly crystalline materials. Atmospheric water that is taken up by the vapor source can be sufficient to reduce crystallinity dramatically. This complication can be partially overcome by increasing the amount of acetic acid in the vapor source.

Litiumjonbatterier (LIB) är viktiga komponenter i dagens teknologi och används för att driva en mängd olika elektroniska system, allt från datorer och mobiltelefoner till bilar och flygplan. Eftersom efterfrågan på effektiv energilagring fortsätter att växa finns ett fortsatt behov för forskning och utveckling inom området. Denna rapport undersöker hårt kol, ett lovande material för anoder i litiumjonbatterier och andra alkali-jon batterier. I likhet med grafit är hårt kol ett kolbaserat material som inte är en väldefinierad allotropp utan en komplex blandning med avseende på både hybridiseringstillstånd och långdistansordning. Därför är den mycket dåligt definierat. Ändå är hårt kol ett önskvärt material eftersom det kan produceras från förnybara resurser samt på grund av dess kompatibilitet med natrium, vilket möjliggör natriumjonbatterier. I den här studien har elektroder av hårt kol syntetiserats och litierats i olika grader och sedan studerats med 7Li NMR-spektroskopi där både spektra och longitudinella relaxationshastigheter mättes. Vid lägre litieringsnivåer observerades tydliga smala 7Li toppar inom intervallet 4-16 ppm, vilket indikerar förekomsten av joniskt litium. Vid högre litieringsnivåer framträdde en bred topp vid 61 ppm. Utseendet av denna topp, tillsammans med en hög Knight-skift, indikerar närvaron av kvasi-metalliskt litium. Det är värt att notera att detta kvasi-metalliska litium finns i de oordnade och porösa områdena hos hård kol. 7Li longitudinella relaxationshastigheter, som rapporterar om jonisk dynamik, registrerades vid olika temperaturer och från det observerade temperaturberoendet beräknades den genomsnittliga aktiveringsenergin för de involverade joniska rörelserna. Intressant nog visade sig denna aktiveringsenergi vara lägre jämfört med den i PAN-baserade kolfibrer och grafit, som båda uppvisar en högre grad av ordning. Denna observation tyder på ett samband mellan lokal oordning och snabbare jondynamik., Lithium-ion batteries (LIB) are vital components of modern technology, powering a wide range of devices from computers and cell phones to cars and aeroplanes. As the demand for efficient energy storage continues to grow, research and development in the field of lithium-ion batteries remain active. This report focuses on the investigation of hard carbon, a promising anode material for lithium-ion batteries and other alkali-ion batteries. Akin to graphite, hard carbon is a carbon-based material that is not a well-defined allotrope but a complex mixture with regard to both hybridization state and long-range order. Hence it is very poorly defined. Yet, hard carbon is a desirable material as it can be produced from renewable resources and because of its compatibility with sodium, allowing for sodium-ion batteries. In this study, hard carbon electrodes were synthesised and lithiated to various degrees and then studied with 7Li NMR spectroscopy where both spectra and longitudinal relaxation rates were measured. At lower lithiation levels, distinct narrow 7Li peaks were observed within the 4-16 ppm range, indicating the presence of ionic lithium. At higher lithiation levels a broad peak at 61 ppm emerged. The appearance of this peak, along with a high Knight shift, signifies the presence of quasi-metallic lithium, presumably in the more disordered and more porous regions of hard carbon. The 7Li longitudinal relaxation rates, reporting on ionic dynamics, were recorded at different temperature and from the observed temperature dependence the average activation energy for the involved ionic motions was calculated. Interestingly, this activation energy was found to be lower compared to that for PAN-based carbon fibres and graphite, both of which exhibit a higher degree of order. This observation suggests a correlation between local disorder and faster ion dynamics.

(1) Background: antimicrobial resistance is becoming a dramatic problem for public health, and the design of new antimicrobial agents is an active research area. (2) Methods: based on our previous work, we designed an improved version of the crabrolin peptide and characterized its functional and structural properties with a wide range of techniques. (3) Results: the newly designed peptide, crabrolin21, is much more active than the previous ones and shows specific selectivity towards bacterial cells. (4) Conclusions: crabrolin21 shows interesting properties and deserves further studies.

Solid-state NMR (ssNMR) spectroscopy facilitates the non-destructive characterization of structurally heterogeneous biomolecules in their native setting, for example, comprising proteins, lipids and polysaccharides. Here we demonstrate the utility of high and ultra-high field 1 H-detected fast MAS ssNMR spectroscopy, which exhibits increased sensitivity and spectral resolution, to further elucidate the atomic-level composition and structural arrangement of the cell wall of Schizophyllum commune, a mushroom-forming fungus from the Basidiomycota phylum. These advancements allowed us to reveal that Cu(II) ions and the antifungal peptide Cathelicidin-2 mainly bind to cell wall proteins at low concentrations while glucans are targeted at high metal ion concentrations. In addition, our data suggest the presence of polysaccharides containing N-acetyl galactosamine (GalNAc) and proteins, including the hydrophobin proteins SC3, shedding more light on the molecular make-up of cells wall as well as the positioning of the polypeptide layer. Obtaining such information may be of critical relevance for future research into fungi in material science and biomedical contexts.

Asphaltenes from various sources and processed in different ways were studied by nuclear magnetic resonance (NMR) relaxation and diffusion ordered spectroscopy (DOSY) methods. The study investigating samples obtained from various depths of an oil well from a Saudi Arabian deposit found those samples to exhibit increasing aggregate sizes with depths, with the molecular structure remaining essentially unchanged. DOSY experiments reveal three distinct asphaltene aggregation states in different solvents, with increasing particle sizes at greater depths. However, hardware limitations were observed in resolving particle sizes beyond 4 nm. Asphaltenes from in-situ pyrolyzed American oil shale were characterized with respect to maturity, showing that aggregate size increases with maturity. As part of an international effort to characterize one particular crude and sonicated sample from Colombia (PetroPhase 2017), this study found that sonication reduces the aggregate size. Three fluorinated probes were tested to study a Kuwaiti asphaltene sample by 19F NMR spectroscopy and the results were compared to those obtained using the 1H signals of the sample; perfluorooctanoic acid (PFOA) was found to be an effective probe for asphaltene aggregation, mirroring the results of the minor component of the 1H relaxation dispersion analysis. In relaxation dispersion measurements of all four asphaltene types, two mobility regimes were observed with percentage contributions varying between asphaltene origins but being unchanged with respect to processing and sample depth. The behaviour of the contributions of the two mobility regimes in all samples cannot be explained by attributing them to different aggregation states, but a core-shell model is proposed with the more mobile component being on the outside ‘shell’ and the more rigid component constituting the core of a nanoparticle.

The structure of the O-antigen from the international reference strain Escherichia coli O93:-:H16 has been determined. A nonrandom modal chain-length distribution was observed for the lipopolysaccharide, a pattern which is typical when long O-specific polysaccharides are expressed. By a combination of (i) bioinformatics information on the gene cluster related to O-antigen synthesis including putative function on glycosyl transferases, (ii) the magnitude of NMR coupling constants of anomeric protons, and (iii) unassigned 2D H-1, C-13-HSQC, and H-1,H-1-TOCSY NMR spectra it was possible to efficiently elucidate the structure of the carbohydrate polymer in an automated fashion using the computer program CASPER. The polysaccharide also carries O-acetyl groups and their locations were determined by 2D NMR experiments showing that similar to 1/2 of the population was 2,6-di-O-acetylated, similar to 1/4 was 2-O-acetylated, whereas similar to 1/4 did not carry O-acetyl group(s) in the 3-O-substituted mannosyl residue of the repeating unit. The structure of the tetrasaccharide repeating unit of the O-antigen is given by: -> 2)-beta-D-Manp-(1 -> 3)-beta-D-Manp2Ac6Ac-(1 -> 4)-beta-D-GlcpA-(1 -> 3)-alpha-D-GlcpNAc-(1 ->, which should also be the biological repeating unit and it shares structural elements with capsular polysaccharides from E. coli K84 and K50. The structure of the acidic O-specific polysaccharide from Cellulophaga baltica strain NN015840(T) differs to that of the O-antigen from E. coli O93 by lacking the O-acetyl group at O6 of the O-acetylated mannosyl residue.

Since the outbreak of the COVID-19 pandemic in December 2019, SARS-CoV-2 has generated awareness for the requirement of novel antiviral drugs that target new proteins. Previous studies have pointed to the pathogenic significance of the non-structural protein 1 (Nsp1), which was proposed to be a major virulence factor due to its dual role in host translation inhibition and viral replication of SARSCoV- 2. The precise mechanisms of these two functions of Nsp1 are still uncovered. Here, I report the backbone chemical-shift assignments and the atomic-resolution NMR structure of full-length Nsp1 from SARS-CoV-2 solved by NMR. I found that Cov-2 Nsp1 consists of a folded N-terminal domain and an unfolded C-terminal region. Previous studies have identified a surface of the folded N-terminal domain of Nsp1 that associates with both host mRNA, in its function as inhibitor of the host protein translation, and the viral 5’-UTR RNA, in its function as promoter of viral protein translation. I found that the acidic C-terminal tail of Nsp1 folds back on this surface and masks the RNA binding site. A recent Cryo-EM study has shown that the end of C-terminal region of Nsp1 interacts with the mRNA entry tunnel on the 40S subunit of the ribosome, thus inhibiting host mRNA entry and promoting its degradation. I propose that the RNA binding site on the Nsp1 N-terminal domain is protected by its C-terminal tail before Nsp1 contacts the ribosome. Upon ribosome binding, the C-terminal tail is displaced, and the RNA binding site is exposed to recruit either host mRNA or the viral 5’ UTR. My findings have consequences for the design of drugs targeting the RNA binding surface of Nsp1, as it demonstrates the need to develop a molecule that can not only recognize this surface with high affinity, but also displace the C-terminal tail to render this surface accessible. In bacteria, the unfoldase ClpC is a member of the conserved Hsp100/Clp family of AAA+ ATPases and is involved in various cellula

Millipedes are known to produce various sets of chemical compounds in exocrine defensive glands to protect themselves against predators and microorganisms. Here, we reanalyzed the gland secretion of Polyzonium germanicum, a millipede of the order Polyzoniida, by using a combination of analytical techniques such as GC-MS, LC-HRMS and high field 1D and 2D NMR spectroscopy. Previously only one compound (polyzonimine, 1) had been described, but our approach allowed us to add six compounds to the defensive chemistry of this species. Besides polyzonimine (1), we found nitropolyzonamine (2) and five new compounds: 3 (2,3-dimethyl-7'-nitro-2',3',5',6',7',7a'-hexahydrospiro[cyclopent-2-ene-1,1'-pyrrolizine]), 4 (2,3-dimethyl-7'-nitro-2',3',5',6',7',7a'-hexahydrospiro[cyclopentane-1,1'-pyrrolizin]-2-ene), 5 ((1Z)-8,9-dimethyl-1-(nitromethylidene)-2-azaspiro[4.4]non-8-en-7-one), and not fully identified compounds A, B. For compounds 3-5 we were able to determine the molecular constitution, for two of them (4, 5) we were able to give relative configurations. Overall, the combination of advanced analytical techniques applied herein allowed detailed insights into the defensive chemistry of P. germanicum with a low number of individuals needed for analysis and without prior compound isolation.

Water is known to play an important role for the crystallization and stability of Zr-based metal-organic frameworks (MOFs). This work investigates its effect on the vapor-assisted conversion (VAC) synthesis of UiO-67 MOF thin films on Au-coated Si substrates. We demonstrate the equilibration processes taking place during the VAC procedure, confirming the gradual equilibration of all solutions upon heating. The presence of water affects the vapor phase composition but does not significantly impact the acetic acid equilibration rate. However, the preparation of UiO-67 thin films by VAC is highly sensitive to the water content in the reaction. Some water is required for the formation of the zirconium clusters, but excessive water in the reaction vial yields poorly crystalline materials. Atmospheric water that is taken up by the vapor source can be sufficient to reduce crystallinity dramatically. This complication can be partially overcome by increasing the amount of acetic acid in the vapor source.

The ability to adjust conformations in response to the polarity of the environment, i.e. molecular chameleonicity, is considered to be important for conferring both high aqueous solubility and high cell permeability to drugs in chemical space beyond Lipinski's rule of 5. We determined the conformational ensembles populated by the antiviral drugs asunaprevir, simeprevir, atazanavir and daclatasvir in polar (DMSO-d6) and non-polar (chloroform) environments with NMR spectroscopy. Daclatasvir was fairly rigid, whereas the first three showed large flexibility in both environments, that translated into major differences in solvent accessible 3D polar surface area within each conformational ensemble. No significant differences in size and polar surface area were observed between the DMSO-d6 and chloroform ensembles of these three drugs. We propose that such flexible compounds are characterized as “partial molecular chameleons” and hypothesize that their ability to adopt conformations with low polar surface area contributes to their membrane permeability and oral absorption.

Millipedes are known to produce various sets of chemical compounds in exocrine defensive glands to protect themselves against predators and microorganisms. Here, we reanalyzed the gland secretion of Polyzonium germanicum, a millipede of the order Polyzoniida, by using a combination of analytical techniques such as GC-MS, LC-HRMS and high field 1D and 2D NMR spectroscopy. Previously only one compound (polyzonimine, 1) had been described, but our approach allowed us to add six compounds to the defensive chemistry of this species. Besides polyzonimine (1), we found nitropolyzonamine (2) and five new compounds: 3 (2,3-dimethyl-7'-nitro-2',3',5',6',7',7a'-hexahydrospiro[cyclopent-2-ene-1,1'-pyrrolizine]), 4 (2,3-dimethyl-7'-nitro-2',3',5',6',7',7a'-hexahydrospiro[cyclopentane-1,1'-pyrrolizin]-2-ene), 5 ((1Z)-8,9-dimethyl-1-(nitromethylidene)-2-azaspiro[4.4]non-8-en-7-one), and not fully identified compounds A, B. For compounds 3-5 we were able to determine the molecular constitution, for two of them (4, 5) we were able to give relative configurations. Overall, the combination of advanced analytical techniques applied herein allowed detailed insights into the defensive chemistry of P. germanicum with a low number of individuals needed for analysis and without prior compound isolation.

The ability to adjust conformations in response to the polarity of the environment, i.e. molecular chameleonicity, is considered to be important for conferring both high aqueous solubility and high cell permeability to drugs in chemical space beyond Lipinski's rule of 5. We determined the conformational ensembles populated by the antiviral drugs asunaprevir, simeprevir, atazanavir and daclatasvir in polar (DMSO-d6) and non-polar (chloroform) environments with NMR spectroscopy. Daclatasvir was fairly rigid, whereas the first three showed large flexibility in both environments, that translated into major differences in solvent accessible 3D polar surface area within each conformational ensemble. No significant differences in size and polar surface area were observed between the DMSO-d6 and chloroform ensembles of these three drugs. We propose that such flexible compounds are characterized as “partial molecular chameleons” and hypothesize that their ability to adopt conformations with low polar surface area contributes to their membrane permeability and oral absorption.

Millipedes are known to produce various sets of chemical compounds in exocrine defensive glands to protect themselves against predators and microorganisms. Here, we reanalyzed the gland secretion of Polyzonium germanicum, a millipede of the order Polyzoniida, by using a combination of analytical techniques such as GC-MS, LC-HRMS and high field 1D and 2D NMR spectroscopy. Previously only one compound (polyzonimine, 1) had been described, but our approach allowed us to add six compounds to the defensive chemistry of this species. Besides polyzonimine (1), we found nitropolyzonamine (2) and five new compounds: 3 (2,3-dimethyl-7'-nitro-2',3',5',6',7',7a'-hexahydrospiro[cyclopent-2-ene-1,1'-pyrrolizine]), 4 (2,3-dimethyl-7'-nitro-2',3',5',6',7',7a'-hexahydrospiro[cyclopentane-1,1'-pyrrolizin]-2-ene), 5 ((1Z)-8,9-dimethyl-1-(nitromethylidene)-2-azaspiro[4.4]non-8-en-7-one), and not fully identified compounds A, B. For compounds 3-5 we were able to determine the molecular constitution, for two of them (4, 5) we were able to give relative configurations. Overall, the combination of advanced analytical techniques applied herein allowed detailed insights into the defensive chemistry of P. germanicum with a low number of individuals needed for analysis and without prior compound isolation.

The ability to adjust conformations in response to the polarity of the environment, i.e. molecular chameleonicity, is considered to be important for conferring both high aqueous solubility and high cell permeability to drugs in chemical space beyond Lipinski's rule of 5. We determined the conformational ensembles populated by the antiviral drugs asunaprevir, simeprevir, atazanavir and daclatasvir in polar (DMSO-d6) and non-polar (chloroform) environments with NMR spectroscopy. Daclatasvir was fairly rigid, whereas the first three showed large flexibility in both environments, that translated into major differences in solvent accessible 3D polar surface area within each conformational ensemble. No significant differences in size and polar surface area were observed between the DMSO-d6 and chloroform ensembles of these three drugs. We propose that such flexible compounds are characterized as “partial molecular chameleons” and hypothesize that their ability to adopt conformations with low polar surface area contributes to their membrane permeability and oral absorption.

Millipedes are known to produce various sets of chemical compounds in exocrine defensive glands to protect themselves against predators and microorganisms. Here, we reanalyzed the gland secretion of Polyzonium germanicum, a millipede of the order Polyzoniida, by using a combination of analytical techniques such as GC-MS, LC-HRMS and high field 1D and 2D NMR spectroscopy. Previously only one compound (polyzonimine, 1) had been described, but our approach allowed us to add six compounds to the defensive chemistry of this species. Besides polyzonimine (1), we found nitropolyzonamine (2) and five new compounds: 3 (2,3-dimethyl-7'-nitro-2',3',5',6',7',7a'-hexahydrospiro[cyclopent-2-ene-1,1'-pyrrolizine]), 4 (2,3-dimethyl-7'-nitro-2',3',5',6',7',7a'-hexahydrospiro[cyclopentane-1,1'-pyrrolizin]-2-ene), 5 ((1Z)-8,9-dimethyl-1-(nitromethylidene)-2-azaspiro[4.4]non-8-en-7-one), and not fully identified compounds A, B. For compounds 3-5 we were able to determine the molecular constitution, for two of them (4, 5) we were able to give relative configurations. Overall, the combination of advanced analytical techniques applied herein allowed detailed insights into the defensive chemistry of P. germanicum with a low number of individuals needed for analysis and without prior compound isolation.

The ability to adjust conformations in response to the polarity of the environment, i.e. molecular chameleonicity, is considered to be important for conferring both high aqueous solubility and high cell permeability to drugs in chemical space beyond Lipinski's rule of 5. We determined the conformational ensembles populated by the antiviral drugs asunaprevir, simeprevir, atazanavir and daclatasvir in polar (DMSO-d6) and non-polar (chloroform) environments with NMR spectroscopy. Daclatasvir was fairly rigid, whereas the first three showed large flexibility in both environments, that translated into major differences in solvent accessible 3D polar surface area within each conformational ensemble. No significant differences in size and polar surface area were observed between the DMSO-d6 and chloroform ensembles of these three drugs. We propose that such flexible compounds are characterized as “partial molecular chameleons” and hypothesize that their ability to adopt conformations with low polar surface area contributes to their membrane permeability and oral absorption.

Actinides (An) play an important role in chemical research and environmental science related to the nuclear industry or nuclear waste repositories. Investigating their coordination chemistry can function as a tool to obtain fundamental understanding of actinide binding. Due to the radiotoxicity of actinide complexes, special care in handling those material is needed in form of working in a controlled area lab. Therefore, the understanding of complexation properties of the actinides, in particular the transuranium (TRU) elements, is lacking behind those of the d- or 4f-elements. For the early actinides possible oxidation states typically range from +II to +VII. A suitable approach to explore fundamental physico-chemical properties of the actinides is to study series of isostructural An compounds in which the An is in the same oxidation state. Therefore, our investigations are directed towards the synthesis of actinide complexes (An = Th, U, Np, and Pu) with the f-element in the oxidation state IV, the dominant oxidation state particularly under anoxic conditions. Observed changes in e.g. the binding situation or magnetic effects along such series deliver insight into the elements’ unique electronic properties mainly originating from the f-electrons. One important question in the field of An chemistry is the degree of “covalency” in compounds across the An series, which may be addressed by systematic studies on series of An compounds, including transuranium (TRU) elements. An complexes using ambidentate ligand systems can give valuable information on covalency differences between soft and hard donor atoms in one complex system. We therefore chose the 2-mercaptopyridyl ligand system (PyS) as monoanionic ambidentate S,N-moiety. Due to possible resonance structures in the ligand backbone, the negative charge can be distributed over both donor atoms. This leaves sufficient flexibility for PyS to coordinate to the actinide atom in a S- or N-monodentate or S,N-chelating man

Although the chemistry of uranium alkoxides has been widely studied, not much attention has been paid to alkoxide chemistry of transuranic elements. In 1967, Samulski and Karraker were able to isolate a few examples of transuranic alkoxides. However, these complexes were only characterized using elemental analysis and absorption spectra. These compounds were never structurally characterized. Based on recent achievements in synthesizing novel transuranic starting materials, we were able to isolate four mono- and bimetallic tert-butoxides with Np(IV). [Np₃O(OtBu)₁₀] and [K₄Np₂O(OtBu)₁₀] were synthesized using the ligand substitution between neptunium(IV) silylamides and HOtBu, whereas the salt metathesis between [NpCl₄(DME)₂] (DME = dimethoxyethane) and various amounts of LiOtBu resulted in the formation of the oxo-free alkoxides [Np(OtBu)₄(py)₂] (py = pyridine) and [Li(THF)]₂[Np(OtBu)₆]. To the best of our knowledge, these compounds represent the first structurally characterized Np(IV) alkoxides using single crystal X-ray diffraction and solid-state UV-vis-NIR spectroscopy. Furthermore, treatment of [Np(OtBu)₄(py)₂] with [Fe(OtBu)₃]₂ results in the formation of a heterobimetallic complex [NpFe(OtBu)₇(py)]. A solvent dependent coordination motif on both metal sides was observed, leading to the formation of [NpFe(OtBu)₇].

Our research aims at a better understanding of fundamental processes defining transport and accumulation of radiotoxic elements such as U, Np, Pu, Am, Cm, as well as Tc and Se. This requires knowledge of their mobility in the environment and of their (radio)ecological behavior. The results will help to develop biochemically and radiochemically founded risk assessment schemes, remediation procedures in areas affected by uranium mining, and help to assess the long-term safety of final disposal sites for nuclear waste in geologic formations. Therefore, we apply solution- and solid-state NMR to various simple and complex systems. Occasionally, lanthanide ions, Ln(III), are used as non-radioactive, isoelectronic analogs for trivalent actinides, An(III). Radionuclide complexation by small molecules is studied for, e.g., citrate [1,2], glutathione (GSH/GSSG) [3,4], as well as 2-phosphonobutane-1,2,4,-tricarbox-ylate (PBTC) [5] and nitrilotriacetate (NTA) [6]. Selenium and (organo)borates were subject of NMR studies, too [7–9]. Comprehensive kinetic and thermodynamic studies were performed for water addition to PQQ, a redox cofactor in Ln(III)-dependent alcohol dehydrogenases [10]. Indicator molecules excreted from carrot cells or fungi upon treatment with uranium were identified also by NMR [11,12]. Furthermore, the bulk structure as well as the interaction of organics (e.g., gluconate, PBTC) and/or radionuclides with calcium (aluminate) silicate hydrate (C (A )S H) phases related to cementitious materials critical for nuclear waste disposal infrastructures were characterized by 13C, 31P, 27Al, and 29Si MAS NMR [13,14]. Literature: [1] J. Kretzschmar et al., Chem. Commun. 2020, 56, 13133. [2] J. Kretzschmar et al., Inorg. Chem. 2021, 60, 7998. [3] J. Kretzschmar et al., Chem. Commun. 2018, 54, 8697. [4] J. Kretzschmar et al., Inorg. Chem. 2020, 59, 4244. [5] J. Kretzschmar et al., Molecules 2022, 27, 4067. [6] S. Friedrich et al., Molecules 2023, submitted. [7] J. Kretzsch

Actinides (An) play an important role in chemical research and environmental science related to the nuclear industry or nuclear waste repositories. Investigating their coordination chemistry can function as a tool to obtain fundamental understanding of actinide binding. Due to the radiotoxicity of actinide complexes, special care in handling those material is needed in form of working in a controlled area lab. Therefore, the understanding of complexation properties of the actinides, in particular the transuranium (TRU) elements, is lacking behind those of the d- or 4f-elements. For the early actinides possible oxidation states typically range from +II to +VII. A suitable approach to explore fundamental physico-chemical properties of the actinides is to study series of isostructural An compounds in which the An is in the same oxidation state. Therefore, our investigations are directed towards the synthesis of actinide complexes (An = Th, U, Np, and Pu) with the f-element in the oxidation state IV, the dominant oxidation state particularly under anoxic conditions. Observed changes in e.g. the binding situation or magnetic effects along such series deliver insight into the elements’ unique electronic properties mainly originating from the f-electrons. One important question in the field of An chemistry is the degree of “covalency” in compounds across the An series, which may be addressed by systematic studies on series of An compounds, including transuranium (TRU) elements. An complexes using ambidentate ligand systems can give valuable information on covalency differences between soft and hard donor atoms in one complex system. We therefore chose the 2-mercaptopyridyl ligand system (PyS) as monoanionic ambidentate S,N-moiety. Due to possible resonance structures in the ligand backbone, the negative charge can be distributed over both donor atoms. This leaves sufficient flexibility for PyS to coordinate to the actinide atom in a S- or N-monodentate or S,N-chelating man

In this work, the pathways to the formation of the series of mononuclear [RuCl2(CO)2(ERR’)2] complexes from [RuCl2(CO)3]2 and ERR’ or E2Tpn2 (E = S, Se, Te; R, R’ = Me, Ph; Tpn = thiophen-2-yl) were explored by experimental and computational techniques. The reactions were monitored by 77Se and 125Te NMR spectroscopy and the products were characterized by 13C{1H}, 77Se, and 125Te NMR spectroscopy, as well as by single-crystal X-ray crystallography. The treatment of [RuCl2(CO)3]2 with ERR’ (E = S, Se, Te; R, R’= Me, Ph) in CH2Cl2 or THF produced [RuCl2(CO)2(ERR’)2] and [RuCl2(CO)3(ERR’)]. The yields were rather similar in both solvents, but the reactions were faster in THF than in CH2Cl2. The highest yields were observed for the telluroether complexes, and the yields decreased with lighter chalcogenoethers which was consistent with the computed energetics. All [RuCl2(CO)2(ERR’)2] complexes were cis(Cl), cis(CO), trans(ERR’)-isomers. This is consistent with the relative trans-influence strengths of the different donor atoms involved in the coordination sphere around ruthenium. The 77Se and 125Te NMR spectra of the complexes with symmetric chalcogenoether ligands (ER2) exhibited one resonance, whereas with unsymmetric chalcogenoether ligands (ERR’) two close-lying resonances were observed due to the presence of two discrete stereoisomers. The PBE0-D3/def2-TZVP calculations of the reaction pathways showed that the energetics is independent of the nature of the solvent and that thermal energy at room temperature is sufficient to cleave the bridging Ru–Cl bonds in [RuCl2(CO)3]2, which can then react with ERR’. The substitution of one CO ligand of the intermediate [RuCl2(CO)3(ERR’)] by the second ERR’ is the rate-determining step in all reactions. The reaction between [RuCl2(CO)3]2 and Te2Tpn2 (Tpn = thiophen-2-yl) afforded cct-[RuCl2(CO)2(TeTpn2)2] and TeTpn2 together with the precipitation of tellurium. The decomposition of Te2Tpn2 into TeTpn2 was monitored by 12, Tiivistelmä Tässä väitöskirjatyössä tutkittiin sekä kokeellisesti että laskennallisesti mononukleaaristen [RuCl2(CO)2(ERR’) 2] kompleksien muodostumisreittejä. [RuCl2(CO)3]2:n reaktioita ERR’:n ja E2Tpn2:n (E = S, Se, Te; R, R’ = Me, Ph; Tpn = tiofen-2-yyli) kanssa seurattiin 77Se- ja 125Te NMR-spektroskopian avulla. Kaikki tuotteet karakterisoitiin 13C{1H}, 77Se ja 125Te NMR-spektroskopialla sekä röntgenkristallografialla. [RuCl2(CO)3]2:n ja ERR’:n (E = S, Se, Te; R, R’ = Me, Ph) välisessä reaktiossa muodostuu [RuCl2(CO)2(ERR’)2]- ja [RuCl2(CO)3(ERR’)]-komplekseja sekä CH2Cl2:ssa että THF:ssa. Kompleksien saannot olivat melko samanlaisia molemmissa liuottimissa, mutta reaktiot olivat nopeampia tetrahydrofuraanissa kuin dikloorimetaanissa. Telluroeetterikompleksien saannot olivat suurimmat, mutta kevyemmillä kalkogenoeetterikomplekseilla pienemmät. Tiheysfunktionaaliset energialaskut ovat yhteensopivat havaittujen trendien kanssa. [RuCl2(CO)2(ERR’)2]-kompleksit esiintyivät cis(Cl), cis(CO), trans(ERR')-isomeereinä. Tämä voidaan selittää ruteniumiin koordinoitujen ligandien suhteellisilla trans-vaikutuksilla. Kun komplekseissa oli symmetrinen kalkogenoeetteriligandi (ER2), havaittiin 77Se ja 125Te NMR-spektreissä vain yksi resonanssi. Mikäli koordinoitunut ligandi oli epäsymmetrinen (ERR’), havaittiin kaksi lähekkäin olevaa resonanssihuippua johtuen kahdesta steroisomeeristä. PBE0-D3/def2-TZVP-laskut osoittivat, että reaktioiden energetiikka on riippumaton liuottimesta ja että lämpöenergia huoneenlämpötilassa riittää katkaisemaan silloittavan Ru–Cl-sidoksen [RuCl2(CO)3]2:ssa. ERR’:n sitoutuminen vapautuneeseen koordinaatiopaikkaan muodostaa välituotteen [RuCl2(CO)3(ERR')]. CO-ligandin substituutio toisella kalkogenoeetteri-molekyylillä ERR’ on reaktionopeuden määräävä vaihe. [RuCl2(CO)3]2:n ja Te2Tpn2:n (Tpn = tiofen-2-yyli) välisessä reaktiossa muodostuu cct-[RuCl2(CO)2(TeTpn2)2]:n ja TeTpn2:n lisäksi telluuria. Te2Tpn2:n hajoamista TeTpn2:ksi seurattiin 125Te NMR-s

Litiumjonbatterier (LIB) är viktiga komponenter i dagens teknologi och används för att driva en mängd olika elektroniska system, allt från datorer och mobiltelefoner till bilar och flygplan. Eftersom efterfrågan på effektiv energilagring fortsätter att växa finns ett fortsatt behov för forskning och utveckling inom området. Denna rapport undersöker hårt kol, ett lovande material för anoder i litiumjonbatterier och andra alkali-jon batterier. I likhet med grafit är hårt kol ett kolbaserat material som inte är en väldefinierad allotropp utan en komplex blandning med avseende på både hybridiseringstillstånd och långdistansordning. Därför är den mycket dåligt definierat. Ändå är hårt kol ett önskvärt material eftersom det kan produceras från förnybara resurser samt på grund av dess kompatibilitet med natrium, vilket möjliggör natriumjonbatterier. I den här studien har elektroder av hårt kol syntetiserats och litierats i olika grader och sedan studerats med 7Li NMR-spektroskopi där både spektra och longitudinella relaxationshastigheter mättes. Vid lägre litieringsnivåer observerades tydliga smala 7Li toppar inom intervallet 4-16 ppm, vilket indikerar förekomsten av joniskt litium. Vid högre litieringsnivåer framträdde en bred topp vid 61 ppm. Utseendet av denna topp, tillsammans med en hög Knight-skift, indikerar närvaron av kvasi-metalliskt litium. Det är värt att notera att detta kvasi-metalliska litium finns i de oordnade och porösa områdena hos hård kol. 7Li longitudinella relaxationshastigheter, som rapporterar om jonisk dynamik, registrerades vid olika temperaturer och från det observerade temperaturberoendet beräknades den genomsnittliga aktiveringsenergin för de involverade joniska rörelserna. Intressant nog visade sig denna aktiveringsenergi vara lägre jämfört med den i PAN-baserade kolfibrer och grafit, som båda uppvisar en högre grad av ordning. Denna observation tyder på ett samband mellan lokal oordning och snabbare jondynamik., Lithium-ion batteries (LIB) are vital components of modern technology, powering a wide range of devices from computers and cell phones to cars and aeroplanes. As the demand for efficient energy storage continues to grow, research and development in the field of lithium-ion batteries remain active. This report focuses on the investigation of hard carbon, a promising anode material for lithium-ion batteries and other alkali-ion batteries. Akin to graphite, hard carbon is a carbon-based material that is not a well-defined allotrope but a complex mixture with regard to both hybridization state and long-range order. Hence it is very poorly defined. Yet, hard carbon is a desirable material as it can be produced from renewable resources and because of its compatibility with sodium, allowing for sodium-ion batteries. In this study, hard carbon electrodes were synthesised and lithiated to various degrees and then studied with 7Li NMR spectroscopy where both spectra and longitudinal relaxation rates were measured. At lower lithiation levels, distinct narrow 7Li peaks were observed within the 4-16 ppm range, indicating the presence of ionic lithium. At higher lithiation levels a broad peak at 61 ppm emerged. The appearance of this peak, along with a high Knight shift, signifies the presence of quasi-metallic lithium, presumably in the more disordered and more porous regions of hard carbon. The 7Li longitudinal relaxation rates, reporting on ionic dynamics, were recorded at different temperature and from the observed temperature dependence the average activation energy for the involved ionic motions was calculated. Interestingly, this activation energy was found to be lower compared to that for PAN-based carbon fibres and graphite, both of which exhibit a higher degree of order. This observation suggests a correlation between local disorder and faster ion dynamics.

In recent decades, the study of anion transport across model lipid bilayer membranes has evolved rapidly. Initially focused on chloride transport using simple synthetic transporters, the field has expanded to encompass the investigation of different anions, the development of new monitoring methods for the understanding of the process, and the creation of new transporters. This thesis touches on all these aspects and can be divided in three parts, each dealing with the transport of a different anion.After a general introduction of the concepts of anion transmembrane transport and the use of synthetic transporters, the second chapter of the thesis addresses the transport of phosphate through the lipid membranes of liposomes, a process never reported previously. The work focuses primarily on the development of two methods for monitoring the transport process: the [Eu.pBOH2]+ assay and the 31P NMR assay. The former relies on emission spectroscopy, while the latter utilizes NMR spectroscopy.Each assay came with its own distinct set of challenges. These include the research of a suitable phosphate-sensitive probe and the acquisition of consistent and clear results, in an emission-based assay. Meanwhile, for the NMR-based assay, the primary aim was to enhance sensitivity and optimize the signal-to-noise ratio. We discuss these challenges and the successful implementation of both methods, along with their application in studying phosphate transport mediated by synthetic carriers. Our results conclusively demonstrate the feasibility of phosphate transport and highlight the influence of pH on the process, given by the prevalence of different forms of the anion, namely H2PO4– (the transported form) and HPO42–. Additionally, our exploration of various efficient chloride transporters, found to be poor phosphate transporters, underscores the difficulty of transporting phosphate.Successively, in the third chapter, we focus on fluoride transport, with a primary emphasis on mechani, Doctorat en Sciences de l'ingénieur et technologie, info:eu-repo/semantics/nonPublished

Inspired by nature, artificial hydrogen bond‐based anion receptors have been developed to achieve high anion selectivity; however, their binding affinity is usually low. The potency of these receptors is usually increased by the introduction of aryl substituents, which withdraw electrons from their binding site through the resonance effect. Here, we show that the polarization of the C(sp 3 )‐H binding site of bambusuril receptors, and thus their potency to bind anions, can be modulated by the inductive effect. The presence of electron‐withdrawing groups on benzyl substituents of bambusurils significantly increases their binding affinities to halides, resulting in the strongest iodide receptor reported to date with an association constant greater than 10 13 M −1 in acetonitrile. A Hammett plot showed that while the bambusuril affinity toward halides linearly increases with the electron‐withdrawing power of their substituents, their binding selectivity remains essentially unchanged., SCOPUS: ar.j, info:eu-repo/semantics/published

Nuclear Magnetic Resonance (NMR) spectroscopy is the most important techniques that has been developed in the recent past decades. Matter, organic compounds and biological and non biological applications ranging from a particular cell to different organs and various tissues. has been investigated through NMR. Aspects of this technique are still under research and many functions and various applications of the NMR are still under process. This review paper is aimed at providing a general overview of the different NMR, main principles and pro and con of NMR spectroscopy. Inspite of all of these we have discussed the various use of NMR in the field of science and medicine and ongoing development of NMR spectroscopy.

Our research aims at a better understanding of fundamental processes defining transport and accumulation of radiotoxic elements such as U, Np, Pu, Am, Cm, as well as Tc and Se. This requires knowledge of their mobility in the environment and of their (radio)ecological behavior. The results will help to develop biochemically and radiochemically founded risk assessment schemes, remediation procedures in areas affected by uranium mining, and help to assess the long-term safety of final disposal sites for nuclear waste in geologic formations. Therefore, we apply solution- and solid-state NMR to various simple and complex systems. Occasionally, lanthanide ions, Ln(III), are used as non-radioactive, isoelectronic analogs for trivalent actinides, An(III). Radionuclide complexation by small molecules is studied for, e.g., citrate [1,2], glutathione (GSH/GSSG) [3,4], as well as 2-phosphonobutane-1,2,4,-tricarbox-ylate (PBTC) [5] and nitrilotriacetate (NTA) [6]. Selenium and (organo)borates were subject of NMR studies, too [7–9]. Comprehensive kinetic and thermodynamic studies were performed for water addition to PQQ, a redox cofactor in Ln(III)-dependent alcohol dehydrogenases [10]. Indicator molecules excreted from carrot cells or fungi upon treatment with uranium were identified also by NMR [11,12]. Furthermore, the bulk structure as well as the interaction of organics (e.g., gluconate, PBTC) and/or radionuclides with calcium (aluminate) silicate hydrate (C (A )S H) phases related to cementitious materials critical for nuclear waste disposal infrastructures were characterized by 13C, 31P, 27Al, and 29Si MAS NMR [13,14]. Literature: [1] J. Kretzschmar et al., Chem. Commun. 2020, 56, 13133. [2] J. Kretzschmar et al., Inorg. Chem. 2021, 60, 7998. [3] J. Kretzschmar et al., Chem. Commun. 2018, 54, 8697. [4] J. Kretzschmar et al., Inorg. Chem. 2020, 59, 4244. [5] J. Kretzschmar et al., Molecules 2022, 27, 4067. [6] S. Friedrich et al., Molecules 2023, submitted. [7] J. Kretzsch

Carbohydrates are ubiquitous in nature and exhibit a multitude of roles. Besides nucleic and amino acids, they can be regarded as the third alphabet of life. They are used as energy source to fuel the cells, as structural building blocks and play a key role in cellular recognition processes. Compared to the other two groups of biomacromolecules, carbohydrates display a higher level of structural complexity by virtue of the number of individual monosaccharide building blocks, as well as the greater number of possibilities of connecting them and additional modifications. This renders a high information content and a good understanding of the structure-function relationship of glycans is important, since the presence or absence of specific structures can make the difference between health and disease. Carbohydrate structures can be characterized and studied by NMR spectroscopy at the atomic level. This process is time-consuming and error-prone, due to the narrow spectral window, in which most carbohydrate resonances are located leading to severe spectral overlap. Computer programs have been developed, aiding this process. This thesis investigates the quality of prediction of NMR chemical shifts of glycopeptides, highly branched oligosaccharide structures and those bearing a non-natural organic aglycone at the reducing end, as well as the automated determination of primary carbohydrate structures from unassigned NMR spectroscopic data thereof. Novel developments of the CASPER program are highlighted. The three-dimensional structure of carbohydrates plays an important role during carbohydrate-protein interactions. This thesis investigates the conformational preferences and dynamics of glycan structures ranging from di- to tetrasaccharides. A particular focus lies on the measurement of transglycosidic 3JCH coupling constants by NMR. Furthermore, the experimental spectroscopic data is compared to results from MD simulations. Synthetic carbohydrate chemistry has a strong fo

Carbohydrates are ubiquitous in nature and exhibit a multitude of roles. Besides nucleic and amino acids, they can be regarded as the third alphabet of life. They are used as energy source to fuel the cells, as structural building blocks and play a key role in cellular recognition processes. Compared to the other two groups of biomacromolecules, carbohydrates display a higher level of structural complexity by virtue of the number of individual monosaccharide building blocks, as well as the greater number of possibilities of connecting them and additional modifications. This renders a high information content and a good understanding of the structure-function relationship of glycans is important, since the presence or absence of specific structures can make the difference between health and disease. Carbohydrate structures can be characterized and studied by NMR spectroscopy at the atomic level. This process is time-consuming and error-prone, due to the narrow spectral window, in which most carbohydrate resonances are located leading to severe spectral overlap. Computer programs have been developed, aiding this process. This thesis investigates the quality of prediction of NMR chemical shifts of glycopeptides, highly branched oligosaccharide structures and those bearing a non-natural organic aglycone at the reducing end, as well as the automated determination of primary carbohydrate structures from unassigned NMR spectroscopic data thereof. Novel developments of the CASPER program are highlighted. The three-dimensional structure of carbohydrates plays an important role during carbohydrate-protein interactions. This thesis investigates the conformational preferences and dynamics of glycan structures ranging from di- to tetrasaccharides. A particular focus lies on the measurement of transglycosidic 3JCH coupling constants by NMR. Furthermore, the experimental spectroscopic data is compared to results from MD simulations. Synthetic carbohydrate chemistry has a strong fo

Although the chemistry of uranium alkoxides has been widely studied, not much attention has been paid to alkoxide chemistry of transuranic elements. In 1967, Samulski and Karraker were able to isolate a few examples of transuranic alkoxides. However, these complexes were only characterized using elemental analysis and absorption spectra. These compounds were never structurally characterized. Based on recent achievements in synthesizing novel transuranic starting materials, we were able to isolate four mono- and bimetallic tert-butoxides with Np(IV). [Np₃O(OtBu)₁₀] and [K₄Np₂O(OtBu)₁₀] were synthesized using the ligand substitution between neptunium(IV) silylamides and HOtBu, whereas the salt metathesis between [NpCl₄(DME)₂] (DME = dimethoxyethane) and various amounts of LiOtBu resulted in the formation of the oxo-free alkoxides [Np(OtBu)₄(py)₂] (py = pyridine) and [Li(THF)]₂[Np(OtBu)₆]. To the best of our knowledge, these compounds represent the first structurally characterized Np(IV) alkoxides using single crystal X-ray diffraction and solid-state UV-vis-NIR spectroscopy. Furthermore, treatment of [Np(OtBu)₄(py)₂] with [Fe(OtBu)₃]₂ results in the formation of a heterobimetallic complex [NpFe(OtBu)₇(py)]. A solvent dependent coordination motif on both metal sides was observed, leading to the formation of [NpFe(OtBu)₇].

Nuclear Magnetic Resonance (NMR) spectroscopy is the most important techniques that has been developed in the recent past decades. Matter, organic compounds and biological and non biological applications ranging from a particular cell to different organs and various tissues. has been investigated through NMR. Aspects of this technique are still under research and many functions and various applications of the NMR are still under process. This review paper is aimed at providing a general overview of the different NMR, main principles and pro and con of NMR spectroscopy. Inspite of all of these we have discussed the various use of NMR in the field of science and medicine and ongoing development of NMR spectroscopy.

Water is known to play an important role for the crystallization and stability of Zr-based metal-organic frameworks (MOFs). This work investigates its effect on the vapor-assisted conversion (VAC) synthesis of UiO-67 MOF thin films on Au-coated Si substrates. We demonstrate the equilibration processes taking place during the VAC procedure, confirming the gradual equilibration of all solutions upon heating. The presence of water affects the vapor phase composition but does not significantly impact the acetic acid equilibration rate. However, the preparation of UiO-67 thin films by VAC is highly sensitive to the water content in the reaction. Some water is required for the formation of the zirconium clusters, but excessive water in the reaction vial yields poorly crystalline materials. Atmospheric water that is taken up by the vapor source can be sufficient to reduce crystallinity dramatically. This complication can be partially overcome by increasing the amount of acetic acid in the vapor source.

Carbohydrates are ubiquitous in nature and exhibit a multitude of roles. Besides nucleic and amino acids, they can be regarded as the third alphabet of life. They are used as energy source to fuel the cells, as structural building blocks and play a key role in cellular recognition processes. Compared to the other two groups of biomacromolecules, carbohydrates display a higher level of structural complexity by virtue of the number of individual monosaccharide building blocks, as well as the greater number of possibilities of connecting them and additional modifications. This renders a high information content and a good understanding of the structure-function relationship of glycans is important, since the presence or absence of specific structures can make the difference between health and disease. Carbohydrate structures can be characterized and studied by NMR spectroscopy at the atomic level. This process is time-consuming and error-prone, due to the narrow spectral window, in which most carbohydrate resonances are located leading to severe spectral overlap. Computer programs have been developed, aiding this process. This thesis investigates the quality of prediction of NMR chemical shifts of glycopeptides, highly branched oligosaccharide structures and those bearing a non-natural organic aglycone at the reducing end, as well as the automated determination of primary carbohydrate structures from unassigned NMR spectroscopic data thereof. Novel developments of the CASPER program are highlighted. The three-dimensional structure of carbohydrates plays an important role during carbohydrate-protein interactions. This thesis investigates the conformational preferences and dynamics of glycan structures ranging from di- to tetrasaccharides. A particular focus lies on the measurement of transglycosidic 3JCH coupling constants by NMR. Furthermore, the experimental spectroscopic data is compared to results from MD simulations. Synthetic carbohydrate chemistry has a strong fo

In Antarctica, ice-free areas can be found along the coast, on mountain peaks, and in the McMurdo Dry Valleys, where microorganisms well-adapted to harsh conditions can survive and reproduce. Metabolic analyses can shed light on the survival mechanisms of Antarctic soil communities from both coastal sites, under different plant coverage stages, and inner sites where slow-growing or dormant microorganisms, low water availability, salt accumulation, and a limited number of primary producers make metabolomic profiling difficult. Here, we report, for the first time, an efficient protocol for the extraction and the metabolic profiling of Antarctic soils based on the combination of NMR spectroscopy and mass spectrometry (MS). This approach was set up on samples harvested along different localities of Victoria Land, in continental Antarctica, devoid of or covered by differently developed biological crusts. NMR allowed for the identification of thirty metabolites (mainly sugars, amino acids, and organic acids) and the quantification of just over twenty of them. UPLC-MS analysis identified more than twenty other metabolites, in particular flavonoids, medium- and long-chain fatty acids, benzoic acid derivatives, anthracenes, and quinones. Our results highlighted the complementarity of the two analytical techniques. Moreover, we demonstrated that their combined use represents the “gold standard” for the qualitative and quantitative analysis of little-explored samples, such as those collected from Antarctic soils.

Asphaltenes from various sources and processed in different ways were studied by nuclear magnetic resonance (NMR) relaxation and diffusion ordered spectroscopy (DOSY) methods. The study investigating samples obtained from various depths of an oil well from a Saudi Arabian deposit found those samples to exhibit increasing aggregate sizes with depths, with the molecular structure remaining essentially unchanged. DOSY experiments reveal three distinct asphaltene aggregation states in different solvents, with increasing particle sizes at greater depths. However, hardware limitations were observed in resolving particle sizes beyond 4 nm. Asphaltenes from in-situ pyrolyzed American oil shale were characterized with respect to maturity, showing that aggregate size increases with maturity. As part of an international effort to characterize one particular crude and sonicated sample from Colombia (PetroPhase 2017), this study found that sonication reduces the aggregate size. Three fluorinated probes were tested to study a Kuwaiti asphaltene sample by 19F NMR spectroscopy and the results were compared to those obtained using the 1H signals of the sample; perfluorooctanoic acid (PFOA) was found to be an effective probe for asphaltene aggregation, mirroring the results of the minor component of the 1H relaxation dispersion analysis. In relaxation dispersion measurements of all four asphaltene types, two mobility regimes were observed with percentage contributions varying between asphaltene origins but being unchanged with respect to processing and sample depth. The behaviour of the contributions of the two mobility regimes in all samples cannot be explained by attributing them to different aggregation states, but a core-shell model is proposed with the more mobile component being on the outside ‘shell’ and the more rigid component constituting the core of a nanoparticle.

Asphaltenes from various sources and processed in different ways were studied by nuclear magnetic resonance (NMR) relaxation and diffusion ordered spectroscopy (DOSY) methods. The study investigating samples obtained from various depths of an oil well from a Saudi Arabian deposit found those samples to exhibit increasing aggregate sizes with depths, with the molecular structure remaining essentially unchanged. DOSY experiments reveal three distinct asphaltene aggregation states in different solvents, with increasing particle sizes at greater depths. However, hardware limitations were observed in resolving particle sizes beyond 4 nm. Asphaltenes from in-situ pyrolyzed American oil shale were characterized with respect to maturity, showing that aggregate size increases with maturity. As part of an international effort to characterize one particular crude and sonicated sample from Colombia (PetroPhase 2017), this study found that sonication reduces the aggregate size. Three fluorinated probes were tested to study a Kuwaiti asphaltene sample by 19F NMR spectroscopy and the results were compared to those obtained using the 1H signals of the sample; perfluorooctanoic acid (PFOA) was found to be an effective probe for asphaltene aggregation, mirroring the results of the minor component of the 1H relaxation dispersion analysis. In relaxation dispersion measurements of all four asphaltene types, two mobility regimes were observed with percentage contributions varying between asphaltene origins but being unchanged with respect to processing and sample depth. The behaviour of the contributions of the two mobility regimes in all samples cannot be explained by attributing them to different aggregation states, but a core-shell model is proposed with the more mobile component being on the outside ‘shell’ and the more rigid component constituting the core of a nanoparticle.

The ability to adjust conformations in response to the polarity of the environment, i.e. molecular chameleonicity, is considered to be important for conferring both high aqueous solubility and high cell permeability to drugs in chemical space beyond Lipinski's rule of 5. We determined the conformational ensembles populated by the antiviral drugs asunaprevir, simeprevir, atazanavir and daclatasvir in polar (DMSO-d6) and non-polar (chloroform) environments with NMR spectroscopy. Daclatasvir was fairly rigid, whereas the first three showed large flexibility in both environments, that translated into major differences in solvent accessible 3D polar surface area within each conformational ensemble. No significant differences in size and polar surface area were observed between the DMSO-d6 and chloroform ensembles of these three drugs. We propose that such flexible compounds are characterized as “partial molecular chameleons” and hypothesize that their ability to adopt conformations with low polar surface area contributes to their membrane permeability and oral absorption.

Inositolpolyphosphate (InsPs) bilden eine ubiquitäre Gruppe an hochphosphorylierten, intrazellulären Signalmolekülen in eukaryotischen Zellen. Trotz deren Beteiligung an unzähligen biologischen Prozessen bleibt die Detektion von InsPs (insb. einzelner Enantiomere) eine Herausforderung, da die momentan verfügbaren Analysemethoden immer noch limitiert sind. In der vorliegenden Arbeit wird die stabile Isotopenmarkierung von myo-Inositol (Ins) und InsPs in Kombination mit Kernspinresonanzspektroskopie (engl. Nuclear Magnetic Resonance spectroscopy, NMR) erkundet, um diese Lücke zu schließen. Die Abhängigkeit von NMR-Daten und chemischer Struktur erlaubte die Analyse komplexer Mixturen aus InsPs aus in vitro-Experimenten und biologischen Proben. Durch stereospezifische 13C-Markierung konnten sogar Enantiomere voneinander unterschieden werden. Mit Hilfe dieser Methode wurden mehrere InsP-Stoffwechselwege untersucht. Als Erstes wurde das menschliche, Phytase-artige Enzym MINPP1 (engl. Multiple Inositol Polyphosphate Phosphatase 1) detailliert in vitro und in lebenden Zellen charakterisiert. Dabei wurde ein bisher unbeschriebener InsP-Stoffwechselweg in menschlichen Zellen erstmals beschrieben. Als Zweites wurden InsP verdauende Bakterien aus der menschlichen Darmflora untersucht, sodass der Abbauweg von Inositolhexakisphosphat beleuchtet werden konnte. Als Drittes wurden DUSP-Enzyme (engl. Dual-Specificity Phosphatases) identifiziert und in vitro charakterisiert, die in der Lage sind, die Phosphoanhydrid-Bindung von Inositolpyrophosphaten (PP-InsPs) zu spalten. Die vorliegende Arbeit demonstriert, dass 13C-Markierung in Verbindung mit NMR ein mächtiges Werkzeug darstellt, um InsP-Stoffwechselvorgänge zu untersuchen., Inositol polyphosphates (InsPs) comprise a ubiquitous group of densely phosphorylated intracellular messengers in eukaryotic cells. Despite their contributions to a myriad of biological processes the detection of InsPs remains challenging to this day, especially with regards to differentiating enantiomers, as the available analytical toolset is still limited. In this thesis the use of stable isotope labelling of myo-inositol (Ins) and InsPs is explored to address this shortcoming. Combining 13C-labelling and nuclear magnetic resonance spectroscopy (NMR) provides both enhanced sensitivity and makes use of NMR’s strong structure-data dependency. This enabled the deconvolution of complex mixtures of InsPs from in vitro experiments or biological samples. With stereo-specific 13C-labels InsP mixtures could be resolved to individual enantiomers. Using this technique several InsP metabolic pathways were examined. Firstly, the human phytase-like enzyme Multiple Inositol Polyphosphate Phosphatase (MINPP1) was characterized in depth in vitro and in living cells, establishing a hitherto undescribed inositol polyphosphate metabolic path in humans. Secondly, inositol phosphate digesting bacteria isolated from the human gut microbiome were investigated, shedding light on the metabolic fate of inositol hexakisphosphate in the digestive track. Thirdly, a set of Dual-Specificity Phosphatases (DUSPs) were identified to be able to hydrolyze the phosphoanhydride bond of inositol pyrophosphates (PP-InsPs) and characterized in vitro. The 13C-labelling approach of InsPs in junction with NMR represents a powerful tool for the study of inositol polyphosphate metabolism. In the thesis at hand, this method has facilitated our understanding of inositol polyphosphate pathways and it will be continuing doing so in the future in several biological contexts.

Millipedes are known to produce various sets of chemical compounds in exocrine defensive glands to protect themselves against predators and microorganisms. Here, we reanalyzed the gland secretion of Polyzonium germanicum, a millipede of the order Polyzoniida, by using a combination of analytical techniques such as GC-MS, LC-HRMS and high field 1D and 2D NMR spectroscopy. Previously only one compound (polyzonimine, 1) had been described, but our approach allowed us to add six compounds to the defensive chemistry of this species. Besides polyzonimine (1), we found nitropolyzonamine (2) and five new compounds: 3 (2,3-dimethyl-7'-nitro-2',3',5',6',7',7a'-hexahydrospiro[cyclopent-2-ene-1,1'-pyrrolizine]), 4 (2,3-dimethyl-7'-nitro-2',3',5',6',7',7a'-hexahydrospiro[cyclopentane-1,1'-pyrrolizin]-2-ene), 5 ((1Z)-8,9-dimethyl-1-(nitromethylidene)-2-azaspiro[4.4]non-8-en-7-one), and not fully identified compounds A, B. For compounds 3-5 we were able to determine the molecular constitution, for two of them (4, 5) we were able to give relative configurations. Overall, the combination of advanced analytical techniques applied herein allowed detailed insights into the defensive chemistry of P. germanicum with a low number of individuals needed for analysis and without prior compound isolation.

Eleven new and three reported half-sandwich Ru(II) arene complexes were synthesized using [Ru(g6-benzene)Cl(l-Cl)]2 and [Ru(g6-toluene)Cl(l-Cl)]2 and four pyridine carboxylic acid-based ligands (dicarboxylic acids and halogen derivatives). The structures and purity of synthesized compounds were confirmed using 1H and 13C NMR spectroscopy, infrared spectroscopy, mass spectrometry, and elemental analysis. The stability of synthesized compounds in dimethyl sulfoxide solution was confirmed using 1H NMR spectroscopy. The seven ligands, two complex precursors (CP1 and CP2), and 14 half-sandwich Ru(II) picolinate complexes (C1–C14) were evaluated for in vitro antibacterial and antifungal activity against pathogens, such as Staphylococcus aureus, Bacillus cereus, Proteus mirabilis, Klebsiella pneumoniae, Ecsherichia coli, Pseudomonas aeruginosa, Salmonella enteritidis, Enterobacter aerogenes, and yeast Candida albicans, using the microwell-dilution method. Among the tested samples, the ligands showed better inhibitory effect against Gram-positive bacteria when compared to the metal complexes. The most susceptible Gram-negative bacteria was Ecsherichia coli, with a MIC value of 1.25 mg/mL, for C3, C6, and C10. All synthesized complexes showed similar, slightly better activity against Candida albicans.

Alginates are industrially relevant polysaccharides widely used in the food and biomedical industries for their excellent gelling properties. The growing emphasis on the valorization of marine resources has evidenced the need for alternative methods for the determination of both alginate content and the M/G ratio. This study describes the application of acid methanolysis and separation by anion exchange chromatography. Five samples, including alginates extracted from Saccharina latissima, Ascophyllum nodosum, a certified standard, and two poly-uronates (Poly-M and Poly-G), were analysed for their M/G ratio and alginate content at different treatment conditions, and compared with other conventionally used or reference methods (NMR, FTIR, and colorimetric methods). Quantitative estimation of alginate was relatively accurate at optimum conditions (4 h at 100 °C), as compared with the certified standard or with other colorimetric methods. M/G ratios were not significantly different from those determined after the reference method (1H NMR) or compared to FTIR protocols. The results evidence that methanolysis may be applied to simultaneously estimate the purity and M/G ratio of alginate-rich samples in a single analysis.

We introduce a deep learning-based deconvolution approach for 1H NMR spectra, developed by leveraging concepts from the field of physics informed-learning, intelligent labeling, and tailored high dynamic range (HDR) spectral preprocessing. Since automation and faster workflows are major concerns in NMR spectroscopy, the algorithm handles uncorrected spectra without strict assumptions on phase and baseline correction as well as line shape. Due to the lack of high quality and consistently labeled experimental spectra in quantities needed to train modern deep learning models, we relied on synthetic spectra creation. Moreover, instead of training with synthetic spectra consisting of single lines, we created synthetic multiples that further supported a realistic deconvolution. We achieved super-human performance on corrected and uncorrected synthetic spectra. Finally, and most importantly, the results on synthetic data translate well to experimental spectra despite the covariate shift. Thus, this tool is a promising candidate for automated expert-level deconvolution of experimental HDR 1H NMR spectra.

The analysis of nuclear magnetic resonance (NMR) spectra to detect peaks and characterize their parameters, often referred to as deconvolution, is a crucial step in the quantification, elucidation, and verification of the structure of molecular systems. However, deconvolution of 1D NMR spectra is a challenge for both experts and machines. We propose a robust, expert-level quality deep learning-based deconvolution algorithm for 1D experimental NMR spectra. The algorithm is based on a neural network trained on synthetic spectra. Our customized pre-processing and labeling of the synthetic spectra enable the estimation of critical peak parameters. Furthermore, the neural network model transfers well to the experimental spectra and demonstrates low fitting errors and sparse peak lists in challenging scenarios such as crowded, high dynamic range, shoulder peak regions as well as broad peaks. We demonstrate in challenging spectra that the proposed algorithm is superior to expert results.