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Efficient and reliable methods for the generation of bioactive papers are of growing interest in relation to point-of-care testing devices that do not require extensive analytical equipment. Herein, we report the immobilization of functional proteins on paper fibers using a modular chemoenzymatic approach. The synthetic strategy relies on a combination of highly efficient spatially controllable photo-triggered cycloaddition followed by site-specific sortase A-catalyzed transamidation. This site-directed and regiospecific method has allowed unidirectional and covalent immobilization of several proteins displaying different functional properties, with ramifications for application in paper-based diagnostics.

In recent years, there has been high interest in paper-based microfluidic sensors or microfluidic paper-based analytical devices (μPADs) towards low-cost, portable, and easy-to-use sensing for chemical and biological targets. μPAD allows spontaneous liquid flow without any external or internal pumping, as well as an innate filtration capability. Although both optical (colorimetric and fluorescent) and electrochemical detection have been demonstrated on μPADs, several limitations still remain, such as the need for additional equipment, vulnerability to ambient lighting perturbation, and inferior sensitivity. Herein, alternative detection methods on μPADs are reviewed to resolve these issues, including relatively well studied distance-based measurements and the newer capillary flow dynamics-based method. Detection principles, assay performance, strengths, and weaknesses are explained for these methods, along with their potential future applications towards point-of-care medical diagnostics and other field-based applications.

Lithium metal anodes (LMAs) with high energy density have recently captured increasing attention for development of next-generation batteries. However, practical viability of LMAs is hindered by the uncontrolled Li dendrite growth and infinite dimension change. Even though constructing 3D conductive skeleton has been regarded as a reliable strategy to prepare stable and low volume stress LMAs, engineering the renewable and lithiophilic conductive scaffold is still a challenge. Herein, a robust conductive scaffold derived from renewable cellulose paper, which is coated with reduced graphene oxide and decorated with lithiophilic Au nanoparticles, is engineered for LMAs. The graphene cellulose fibres with high surface area can reduce the local current density, while the well-dispersed Au nanoparticles can serve as lithiophilic nanoseeds to lower the nucleation overpotential of Li plating. The coupled relationship can guarantee uniform Li nucleation and unique spherical Li growth into 3D carbon matrix. Moreover, the natural cellulose paper possesses outstanding mechanical strength to tolerate the volume stress. In virtue of the modulated deposition behaviour and near-zero volume change, the hybrid LMAs can achieve reversible Li plating/stripping even at an ultrahigh current density of 10 mA cm-2 as evidenced by high Coulombic efficiency (97.2 % after 60 cycles) and ultralong lifespan (1000 cycles) together with ultralow overpotential (25 mV). Therefore, this strategy sheds light on a scalable approach to multiscale design versatile Li host, promising highly stable Li metal batteries to be feasible and practical.

Paper-like electrodes are emerging as a new category of advanced electrodes for flexible supercapacitors (SCs). Graphene, a promising two-dimensional material with high conductivity, can be easily processed into papers. Here, we report a rational design of flexible architecture with Co9 S8 nanotube arrays (NAs) grown onto graphene paper (GP) via a facile two-step hydrothermal method. When employed as flexible free-standing electrode for SCs, the proposed architectured Co9 S8 /GPs exhibits superior electrochemical performance with ultrahigh capacitance and outstanding rate capability (469 F g-1 at 10 A g-1 ). These results demonstrate that the new nanostructured Co9 S8 /GPs can be potentially applied in high performance flexible supercapacitors.

To circumvent the bottlenecks of non‐flexibility, low sensitivity, and narrow workable detection range of conventional biosensors for biological molecule detection (e.g., dopamine (DA) secreted by living cells), a new hybrid flexible electrochemical biosensor has been created by decorating closely packed dendritic Pt nanoparticles (NPs) on freestanding graphene paper. This innovative structural integration of ultrathin graphene paper and uniform 2D arrays of dendritic NPs by tailored wet chemical synthesis has been achieved by a modular strategy through a facile and delicately controlled oil–water interfacial assembly method, whereby the uniform distribution of catalytic dendritic NPs on the graphene paper is maximized. In this way, the performance is improved by several orders of magnitude. The developed hybrid electrode shows a high sensitivity of 2 μA cm−2 μm −1, up to about 33 times higher than those of conventional sensors, a low detection limit of 5 nm, and a wide linear range of 87 nm to 100 μm. These combined features enable the ultrasensitive detection of DA released from pheochromocytoma (PC 12) cells. The unique features of this flexible sensor can be attributed to the well‐tailored uniform 2D array of dendritic Pt NPs and the modular electrode assembly at the oil–water interface. Its excellent performance holds much promise for the future development of optimized flexible electrochemical sensors for a diverse range of electroactive molecules to better serve society.

Fiber supercapacitors are promising energy storage devices for potential application in wearable and miniaturized portable electronics, which currently suffer from difficulties in achieving high capacitance and energy density synchronously owing to the limited specific surface area of the electrode materials and material incompatibility between the two electrodes. Herein, a strategy is developed for the manufacture of coaxial asymmetric fiber supercapacitors by wrapping a core of PVA-KOH gel electrolyte-coated Ni(OH)2 @NiCo2 O4 /CNT fibers with MoS2 @Fe2 O3 /CNT paper. The as-prepared coaxial fiber asymmetric supercapacitors exhibit a specific capacitance of 373 mF cm-2 (at a current density of 2 mA cm-2 ) and energy density of 0.13 mW h cm-2 (at a power density of 3.2 mW cm-2 ), and also show good rate capability, long cycle life, and excellent flexibility. This work provides the possibility for the practical application of fiber supercapacitors in wearable and portable energy storage equipment.

Security inks based on photoluminescent materials are mostly investigated for security applications, such as information encryption and decryption, anti-counterfeiting, and data storage. Although they are invisible to the naked eye under ambient light, they can be detected under ultraviolet or near-infrared light. Herein, a new kind of secret paper made from network-structured ultralong hydroxyapatite nanowires and cellulose fibers has been developed. White vinegar, a common cooking ingredient, is used as an invisible security ink. Covert information on the secret paper written with white vinegar is totally invisible under natural light, but it can be decrypted and clearly read after exposure to fire; the response time to fire is short (

A novel ultra‐low‐cost biochemical analysis platform to quantify protein dissociation binding constants and kinetics using paper microfluidics is reported. This approach marries video imaging with one of humankind's oldest materials: paper, requiring no large, expensive laboratory equipment, complex microfluidics or external power. Temporal measurements of nanoparticle–antibody conjugates binding on paper is found to follow the Langmuir Adsorption Model. This is exploited to measure a series of antibody–antigen dissociation constants on paper, showing excellent agreement with a gold‐standard benchtop interferometer. The concept is demonstrated with a camera and low‐end smartphone, 500‐fold cheaper than the reference method, and can be multiplexed to measure ten reactions in parallel. These findings will help to widen access to quantitative analytical biochemistry, for diverse applications spanning disease diagnostics, drug discovery, and environmental analysis in resource‐limited settings.

A highly flexible and free-standing paper with high antibacterial activity made from silver nanoparticle (AgNP)-decorated ultralong hydroxyapatite nanowires (HAPNWs) is reported. The HAPNWs@AgNPs nanocomposites were obtained from a facile one-step solvothermal process and utilized for the construction of highly flexible and free-standing inorganic paper through a simple vacuum-filtration procedure. The structure and properties of the HAPNWs@AgNPs paper were characterized in detail. Scanning electron microscope (SEM) and transmission electron microscope (TEM) micrographs show that AgNPs are highly dispersed and stabilized in the nanocomposite and exhibit a narrow particle size distribution. The effects of the concentration of silver nitrate, solvothermal temperature and time on the product were systematically investigated. This method is simple, convenient and reproducible. The as-prepared HAPNWs@AgNPs paper shows long-time sustained silver-ion release, high antibacterial activity against both Gram-negative and Gram-positive bacteria, and good biocompatibility. Overall, this work provides a novel pathway for the preparation of a new type of highly flexible, free-standing and antibacterial inorganic paper made from silver nanoparticle-decorated hydroxyapatite nanowires for various applications, as a promising functional biomaterial.

21 p.-14 fig. In Memoriam Prof. Kilian Muñiz (R.I.P.). Excellent person, great heart., The innate immunity TLR4/MD-2 system is a membrane receptor of paramount importance as therapeutic target. Its assembly, upon binding of Gram-negative bacteria lipopolysaccharide (LPS), and also dependent on the membrane composition, finally triggers the immune response cascade. We here combine ab-initio calculations, molecular docking, all-atom molecular dynamics simulations, and thermodynamics calculations to provide the most realistic and complete 3D models of the active full TLR4 complex embedded into a realistic membrane to date. Our studies reveal functional and structural insights into the transmembrane domain behavior in different membrane environments, the ectodomain bouncing movement, and the dimerization patterns of the intracellular TIR domain. Our work provides TLR4 models as reasonable 3D structures for the (TLR4/MD-2/LPS) 2 architecture accounting for the active (agonist) state of the TLR4, and pointing to a signal transduction mechanism across cell membrane. These observations unveil relevant molecular aspects involved in the TLR4 innate immune pathways and will promote the discovery of new TLR4 modulators., This work was financially supported by the Spanish Ministry for Science and Innovation (grants CTQ2014-57141-R, CTQ2017-88353-R, and PID2020-113588RB-I00; grants BES-2012-053653 for L.P.R., BES-2015-071588 for J.G.C. and PRE2018-086249 for A.M.R.), and the European Commission Marie Sklodowska-Curie actions (H2020-MSCA-ITN 642157 “TOLLerant”).

Novel seven‐membered cyclic imine‐based 1,3‐P,N ligands were obtained by capturing a Beckmann nitrilium ion intermediate generated in situ from cyclohexanone with benzotriazole, and then displacing it by a secondary phosphane under triflic acid promotion. These “cycloiminophosphanes” possess flexible non‐isomerizable tetrahydroazepine rings with a high basicity; this sets them apart from previously reported iminophophanes. The donor strength of the ligands was investigated by using their P‐κ1‐ and P,N‐κ2‐tungsten(0) carbonyl complexes, by determining the IR frequency of the trans‐CO ligands. Complexes with [RhCp*Cl2]2 demonstrated the hemilability of the ligands, giving a dynamic equilibrium of κ1 and κ2 species; treatment with AgOTf gives full conversion to the κ2 complex. The potential for catalysis was shown in the RuII‐catalyzed, solvent‐free hydration of benzonitrile and the RuII‐ and IrI‐catalyzed transfer hydrogenation of cyclohexanone in isopropanol. Finally, to enable access to asymmetric catalysts, chiral cycloiminophosphanes were prepared from l‐menthone, as well as their P,N‐κ2‐RhIII and a P‐κ1‐RuII complexes., Complexes, chirality and catalysts: 1,3‐P,N hybrid ligands are broadly applied in cooperative catalysis, but show limited electronic variation. We report novel analogues with a high N‐basicity, based on 7‐membered cyclic imines. Their transition metal complexes demonstrated their donor strength (W), hemilabile coordination (Rh), and catalytic activity for nitrile hydration (Ru) and transfer hydrogenation (Ru, Ir). Chiral derivatives were also obtained, synthesized from l‐menthone.

A series of expanded helicenes of different sizes and shapes incorporating phenyl‐ and biphenyl‐substituents at the deepest part of their fjord have been synthesized via sequential Au‐catalyzed hydroarylation of appropriately designed diynes, and their racemization barriers have been calculated employing electronic structure methods. These show that the overall profile of the inversions (energies, number of transition states and intermediates, and their relative position) is intensively affected by the interplay of steric and attractive London dispersion interactions. Hence, in‐fjord substitution constitutes an additional tool to handle the mechanical properties in helicenes of uncommonly large diameter. The photochemical characterization of the newly prepared helical structures is also reported., Deep in‐fjord substitution is presented as a new tool to control the mechanical properties of expanded helicenes. The syntheses of a series of these compounds containing internal inserts is described and their overall inversion profile is calculated. Interestingly, the interplay between steric and dispersion interactions play a major role in shape of the inversion profiles (energies, number of transition states and intermediates).

A lanthanide‐binding tag site‐specifically attached to a protein presents a tool to probe the protein by multiple spectroscopic techniques, including nuclear magnetic resonance, electron paramagnetic resonance and time‐resolved luminescence spectroscopy. Here a new stable chiral LnIII tag, referred to as C12, is presented for spontaneous and quantitative reaction with a cysteine residue to generate a stable thioether bond. The synthetic protocol of the tag is relatively straightforward, and the tag is stable for storage and shipping. It displays greatly enhanced reactivity towards selenocysteine, opening a route towards selective tagging of selenocysteine in proteins containing cysteine residues. Loaded with TbIII or TmIII ions, the C12 tag readily generates pseudocontact shifts (PCS) in protein NMR spectra. It produces a relatively rigid tether between lanthanide and protein, which is beneficial for interpretation of the PCSs by single magnetic susceptibility anisotropy tensors, and it is suitable for measuring distance distributions in double electron–electron resonance experiments. Upon reaction with cysteine or other thiol compounds, the TbIII complex exhibits a 100‐fold enhancement in luminescence quantum yield, affording a highly sensitive turn‐on luminescence probe for time‐resolved FRET assays and enzyme reaction monitoring., Lanthanoid keys to proteins: A stable chiral lanthanide(III) tag reacts spontaneously and quantitatively with a cysteine residue to generate a stable thioether bond. The lanthanide‐binding tag presents a tool to probe proteins using multiple spectroscopic techniques, including NMR, electron paramagnetic resonance and time‐resolved FRET experiments.

A bis(18‐crown‐6) Tröger's base receptor and 4‐substituted hepta‐1,7‐diyl bisammonium salt ligands have been used as a model system to study the interactions between non‐polar side chains of peptides and an aromatic cavity of a protein. NMR titrations and NOESY/ROESY NMR spectroscopy were used to analyze the discrimination of the ligands by the receptor based on the substituent of the ligand, both quantitatively (free binding energies) and qualitatively (conformations). The analysis showed that an all‐anti conformation of the heptane chain was preferred for most of the ligands, both free and when bound to the receptor, and that for all of the receptor‐ligand complexes, the substituent was located inside or partly inside of the aromatic cavity of the receptor. We estimated the free binding energy of a methyl‐ and a phenyl group to an aromatic cavity, via CH‐π, and combined aromatic CH‐π and π‐π interactions to be −1.7 and −3.3 kJ mol−1, respectively. The experimental results were used to assess the accuracy of different computational methods, including molecular mechanics (MM) and density functional theory (DFT) methods, showing that MM was superior., A model system to study interactions between aromatic cavities and non‐polar side chains was developed and studied by different NMR methods, where a weak but evident side‐chain discrimination was observed. The experimental quantitative and qualitative data was used to evaluate different computational methods, with the conclusion that for this system, molecular mechanics gave more accurate results than density functional theory calculations.

The first total synthesis of the actin‐stabilizing marine natural product geodiamolide H was achieved. Solid‐phase based peptide assembly paired with scalable stereoselective syntheses of polyketide building blocks and an optimized esterification set the stage for investigating the key ring‐closing metathesis. Geodiamolide H and synthetic analogues were characterized for their toxicity and for antiproliferative effects in cellulo, by characterising actin polymerization induction in vitro, and by docking on the F‐actin target and property computation in silico, for a better understanding of structure‐activity relationships (SAR). A non‐natural analogue of geodiamolide H was discovered to be most potent in the series, suggesting significant potential for tool compound design., The F‐actin stabilizing natural product geodiamolide H and its analogues were comprehensively investigated. The first total synthesis of geodiamolide H was enabled by optimized, scalable building block synthesis, improved couplings, and by a ring‐closing metathesis as a key step. Biological profiling of the synthesized library in cells, on target, and in silico uncovered potent and simplified non‐natural analogues. Additional structure‐activity relationship information was extracted for the whole class, useful for tool compound design.

Lanthanide ions are particularly well‐suited for the design of single‐molecule magnets owing to their large unquenched orbital angular momentum and strong spin‐orbit coupling that gives rise to high magnetic anisotropy. Such nanoscopic bar magnets can potentially revolutionize high‐density information storage and processing technologies, if blocking temperatures can be increased substantially. Exploring non‐classical ligand scaffolds with the aim to boost the barriers to spin‐relaxation are prerequisite. Here, the synthesis, crystallographic and magnetic characterization of a series of each isomorphous mono‐ and dinuclear lanthanide (Ln=Gd, Tb, Dy, Ho, Er) complexes comprising tetraimido sulfate ligands are presented. The dinuclear Dy complex [{(thf)2Li(NtBu)2S(tBuN)2DyCl2}2 ⋅ ClLi(thf)2] (1c) shows true signatures of single‐molecule magnet behavior in the absence of a dc field. In addition, the mononuclear Dy and Tb complexes [{(thf)2Li(NtBu)2S(tBuN)2LnCl2(thf)2] (2b,c) show slow magnetic relaxation under applied dc fields., The first series of isomorphous lanthanide Gd to Er complexes containing the tetraimido sulfate ligand renders these compounds compelling to be investigated for their single‐molecule magnet behaviour. The displayed Dy dimer shows slow magnetic relaxation at zero field. The monomeric Tb and Dy complexes show field‐induced single‐molecule magnet behaviour. The ligand holds great potential for higher blocking systems, that is, removal of chloride ions, lithium transmetalation and promotion of the magnetic communication between the metal ions.

The donor strength of bifunctional pyridine‐cyclopentadienyl ligands was altered systematically by the introduction of donating groups in the para‐position of the pyridine. In the resulting chromium complexes an almost linear correlation between donor strength and the nitrogen‐chromium distance as well as the electronic absorption maximum is experimentally observed. The connection of electron‐donating groups in the ligand backbone leads to an efficient transfer of the electronic influences to the catalytically active metal centre without restricting it through steric effects. Therefore, catalytic olefin polymerization activity, which is already very high for the previously studied catalysts, increase considerably by attaching para‐amino groups to the chelating pyridine or quinoline, respectively. Combining electron‐rich indenyl ligands with para‐amino substituted pyridines lead to the highest catalytic activities observed so far for this class of organo chromium olefin polymerisation catalysts. The resulting polymers are of ultra‐high molecular weight and the ability of the catalysts to incorporate co‐monomers is also very high., Catalytic activity in ethylene polymerization with single‐site organochromium complexes increases with number and donor strength of substituents. The new systems allow the formation of ultra‐high molecular weight polyethylene with highest productivity and high co‐monomer incorporation. An almost linear correlation between ligand donor strength and polymerization activity is observed.

Two new atomic/molecular layer deposition processes for depositing crystalline metal‐organic thin films, built from 1,4‐benzenedisulfonate (BDS) as the organic linker and Cu or Li as the metal node, are reported. The processes yield in‐situ crystalline but hydrated Cu‐BDS and Li‐BDS films; in the former case, the crystal structure is of a previously known metal‐organic‐framework‐like structure, while in the latter case not known from previous studies. Both hydrated materials can be readily dried to obtain the crystalline unhydrated phases. The stability and the ionic conductivity of the unhydrated Li‐BDS films were characterized to assess their applicability as a thin film solid polymer Li‐ion conductor., A new organic linker for atomic/molecular layer depositions (ALD/MLD) was demonstrated with copper and lithium metal nodes. The films are crystalline with and without water of crystallization. The applicability of dilithium‐1,4‐benzenedisulfonate as a solid polymer ion conductor is assessed.

The beyond‐Rule‐of‐5 (bRo5) chemical space is a source of new oral drugs and includes large and flexible compounds. Because of their size and conformational variability, bRo5 molecules assume different privileged conformations in the compartments of human body, i. e., they can exhibit chameleonic properties. The elucidation of the ensemble of 3D structures explored by such molecules under different conditions is therefore critical to check the role played by chameleonicity to modulate cell permeability. Here we characterized the conformational ensembles of rifampicin, a bRo5 drug, in polar and nonpolar solvents and in the solid state. We performed NMR experiments, analyzed their results with a novel algorithm and set‐up a pool of ad hoc in silico strategies to investigate crystallographic structures retrieved from the CSD. Moreover, a polarity descriptor often related to permeability (SA‐3D‐PSA) was calculated for all the conformers and its variation with the environment analyzed. Results showed that the conformational behavior of rifampicin in solution and in the solid state is not superposable. The identification of dynamic intramolecular hydrogen bonds can be assessed by NMR spectroscopy but not by X‐ray structures. Moreover, SA‐3D‐PSA revealed that dynamic IMHBs do not provide rifampicin with chameleonic properties. Overall, this study highlights that the peculiarity of rifampicin, which is cell permeable probably because of the presence of static IMHBs but is devoid of any chameleonic behavior, can be assessed by a proper analysis of experimental 3D structures., The bRo5 space includes large and flexible drug candidates which may assume different privileged conformations and exhibit chameleonic properties. We characterized the conformational ensembles of rifampicin in polar and nonpolar solvents and in the solid state. We performed NMR experiments, analyzed CSD structures and calculated a polarity descriptor. Results show that rifampicin is not a chameleon and its conformational behavior in solution and in the solid state is not superposable.

Fluorinated groups are essential for drug design, agrochemicals, and materials science. The bis(trifluoromethyl)amino group is an example of a stable group that has a high potential. While the number of molecules containing perfluoroalkyl, perfluoroalkoxy, and other fluorinated groups is steadily increasing, examples with the N(CF3)2 group are rare. One reason is that transfer reagents are scarce and metal‐based storable reagents are unknown. Herein, a set of CuI and AgI bis(trifluoromethyl)amido complexes stabilized by N‐ and P‐donor ligands with unprecedented stability are presented. The complexes are stable solids that can even be manipulated in air for a short time. They are bis(trifluoromethyl)amination reagents as shown by nucleophilic substitution and Sandmeyer reactions. In addition to a series of benzylbis(trifluoromethyl)amines, 2‐bis(trifluoromethyl)amino acetate was obtained, which, upon hydrolysis, gives the fluorinated amino acid N,N‐bis(trifluoromethyl)glycine., Stable storage solutions: Copper(I) and silver(I) complexes with the bis(trifluoromethyl)amido ligand stabilized by pyridine and phosphane ligands have become accessible. These complexes are thermally stable and can be stored under inert conditions; in contrast to the behavior of other metal salts such as M{N(CF3)2} (M=Cu, Ag). The complexes were found to be convenient reagents for nucleophilic substitution and Sandmeyer reactions, thereby providing access to a series of organic substrates with the bis(trifluoromethyl)amino group.

The development of DNA‐compatible reaction methodologies is a central theme to advance DNA‐encoded screening library technology. Recently, we were able to show that sulfonic acid‐functionalized block copolymer micelles facilitated Brønsted acid‐promoted reactions such as the Povarov reaction on DNA‐coupled starting materials with minimal DNA degradation. Here, the impact of polymer composition on micelle shape, and reaction conversion was investigated. A dozen sulfonic acid‐functionalized block copolymers of different molar mass and composition were prepared by RAFT polymerization and were tested in the Povarov reaction, removal of the Boc protective group, and the Biginelli reaction. The results showed trends in the polymer structure‐micellar catalytic activity relationship. For instance, micelles composed of block copolymers with shorter acrylate ester chains formed smaller particles and tended to provide faster reaction kinetics. Moreover, fluorescence quenching experiments as well as circular dichroism spectroscopy showed that DNA‐oligomer‐conjugates, although highly water‐soluble, accumulated very effectively in the micellar compartments, which is a prerequisite for carrying out a DNA‐encoded reaction in the presence of polymer micelles., It′s a matter of environment: Copolymer micelles attracted DNA oligonucleotide conjugates in aqueous solution despite lacking canonical DNA‐binding motifs. Following accumulation inside micelles, DNA‐coupled starting materials underwent Povarov and Biginelli reactions to target molecules by a localized sulfonic acid. The kinetics of a given reaction were tuned by the chemical environment within the micelles.

Chemistry - a European journal 27(38), 9791-9800 (2021). doi:10.1002/chem.202101126, Multilayered heterostructures comprising of In$_2$O$_3$, SnO$_2$, and Al$_2$O$_3$ were studied for their application in thin-film transistors (TFT). The compositional influence of tin oxide on the properties of the thin-film, as well as on the TFT characteristics is investigated. The heterostructures are fabricated by atomic layer deposition (ALD) at 200 °C, employing trimethylindium (TMI), tetrakis(dimethylamino)tin (TDMASn), trimethylaluminum (TMA), and water as precursors. After post-deposition annealing at 400 °C the thin-films are found to be amorphous, however, they show a discrete layer structure of the individual oxides of uniform film thickness and high optical transparency in the visible region. Incorporation of only two monolayers of Al$_2$O$_3$ in the active semiconducting layer the formation of oxygen vacancies can be effectively suppressed, resulting in an improved semiconducting and switching behavior. The heterostacks comprising of In$_2$O$_3$/SnO$_2$/Al$_2$O$_3$ are incorporated into TFT devices, exhibiting a saturation field-effect mobility ($μ_{sat}$) of 2.0 cm$^2$⋅ V$^{−1}$ s$^{−1}$, a threshold-voltage (V$_{th}$) of 8.6 V, a high current on/off ratio (I$_{On}$/I$_{Off}$) of 1.0×10$^7$, and a subthreshold swing (SS) of 485 mV ⋅ dec$^{−1}$. The stability of the TFT under illumination is also altered to a significant extent. A change in the transfer characteristic towards conductive behavior is evident when illuminated with light of an energy of 3.1 eV (400 nm)., Published by Wiley-VCH, Weinheim

MicroRNAs constitute a class of endogenous, non‐coding RNAs that influence various processes within the cell. By base‐pairing to partially‐complementary sites located in the 3’ untranslated region of target messenger RNAs, microRNAs participate in post‐transcriptional regulation of the majority of human protein‐coding genes. Their dysregulation has been related to many pathological processes and diseases. Thus, an in‐depth understanding of the microRNA mechanisms of action is crucial. Here, we present a new concept of probe design to achieve an efficient and sequence‐independent miRNA‐mRNA cross‐linking. The new strategy is based on the utilization of a controlled mixture of probes for a chosen miRNA, in which a trioxsalen moiety is introduced at the N 4‐position of a selected cytidine through short oligoethylene glycol‐based linkers. In vitro photo‐cross‐linking experiments with mini‐libraries of probes for microRNAs of interest showed variable cross‐linking efficiencies, demonstrating a general applicability of the presented approach., We describe a new class of miRNA probes with photo‐active trioxsalen attached via oligoethylene glycol‐based linkers. These cross‐link to RNA targets in vitro with efficiencies dependent on sequence and linker‐length. By using controlled mixtures of probes, a general approach to efficient covalent target‐capture independent of miRNAs sequence is proposed.

Canonical G‐quadruplexes can adopt a variety of different topologies depending on the arrangement of propeller, lateral, or diagonal loops connecting the four G‐columns. A novel intramolecular G‐quadruplex structure is derived through inversion of the last G‐tract of a three‐layered parallel fold, associated with the transition of a single propeller into a lateral loop. The resulting (3+1) hybrid fold features three syn⋅anti⋅anti⋅anti G‐tetrads with a 3’‐terminal all‐syn G‐column. Although the ability of forming a duplex stem‐loop between G‐tracts seems beneficial for a propeller‐to‐lateral loop rearrangement, unmodified G‐rich sequences resist folding into the new (3+1) topology. However, refolding can be driven by the incorporation of syn‐favoring guanosine analogues into positions of the fourth G‐stretch. The presented hybrid‐type G‐quadruplex structure as determined by NMR spectroscopy may provide for an additional scaffold in quadruplex‐based technologies., Starting with a parallel‐stranded DNA G‐quadruplex, refolding into a novel (3+1) hybrid topology with a propeller‐propeller‐lateral loop architecture and an all‐syn 3’‐terminal G‐tract is reported. Although supported by additional stacking of a lateral duplex hairpin onto an outer G‐tetrad, the structural rearrangement must be enforced through the specific incorporation of syn‐favoring 8‐bromoguanosine analogues into the terminal G‐run.

A transition metal free route to phosphetes featuring an exocyclic alkene unit is presented. In this approach phosphanides are added to a variety of diynes generating phosphaallylic intermediates which depending on the reaction conditions transform either to phosphetes or the corresponding phospholes. Investigation of the reaction mechanism by combined quantum chemical and experimental means identifies phosphole formation as thermodynamically controlled reaction path, whereas kinetic control furnishes the corresponding phosphetes. Structural and luminescence properties of the rare class of phosphetes are explored, as well as for selected key intermediates., New route: Investigation of the phosphanide addition to alkynes revealed that the ring size can be controlled during the cyclization step leading either to phospholes or phosphetes starting from the same reactants.

Photoacids attract increasing scientific attention, as they are valuable tools to spatiotemporally control proton‐release reactions and pH values of solutions. We present the first time‐resolved spectroscopic study of the excited state and proton‐release dynamics of prominent merocyanine representatives. Femtosecond transient absorption measurements of a pyridine merocyanine with two distinct protonation sites revealed dissimilar proton‐release mechanisms: one site acts as a photoacid generator as its pKa value is modulated in the ground state after photoisomerization, while the other functions as an excited state photoacid which releases its proton within 1.1 ps. With a pKa drop of 8.7 units to −5.5 upon excitation, the latter phenolic site is regarded a super‐photoacid. The 6‐nitro derivative exhibits only a phenolic site with similar, yet slightly less photoacidic characteristics and both compounds transfer their proton to methanol and ethanol. In contrast, for the related 6,8‐dinitro compound an intramolecular proton transfer to the ortho‐nitro group is suggested that is involved in a rapid relaxation into the ground state., Transient absorption studies of protonated pyridine‐ and nitro‐merocyanines reveal a pH‐gated photoacidic behaviour. The O‐protic site shows an ultrafast excited state super‐photoacid reactivity at low pH values that is even capable of proton transfer to alcoholic solvents. Remarkably, the pyridine compound exhibits an additional N‐protic site which functions as photoacid generator at pH 5.5 due to its lowered ground state pKa value after photoisomerization to the ring‐closed spiropyran structure.

An electrochemical synthesis of organic polysulfides through sulfur insertion from elemental sulfur to disulfides or thiols is introduced. The highly economic, low‐sensitive and low‐priced reaction gives a mixture of polysulfides, whose distribution can be influenced by the addition of different amounts of carbon disulfide as co‐solvent. To describe the variable distribution function of the polysulfides, a novel parameter, the “absorbance average sulfur amount in polysulfides” (SAP) was introduced and defined on the basis of the “number average molar mass” used in polymer chemistry. Various organic polysulfides were synthesized with variable volume fractions of carbon disulfide, and the yield of each polysulfide was determined by quantitative 13C NMR. Moreover, by using two symmetrical disulfides or a disulfide and a thiol as starting materials, a mixture of symmetrical and asymmetrical polysulfides could be obtained., Electrifying Sulfur! The electrolysis of organic disulfides in dichloromethane led to the formation of organic polysulfides with a high incorporation of additional sulfur atoms. HPLC/HRMS analysis of the reaction mixture could identify products up to undecasulfides. When CS2 was used as co‐solvent the distribution of the organic polysulfide mixture was altered in favor of the lower polysulfides, such as tri‐ and tetrasulfides.

Ambifunctional heterpentacenes with the heteroatom sequence SSNSS in the ladder‐type backbone were used either as donor or as nonfullerenic acceptor in solution‐processed bulk‐heterojunction solar cells. Different acceptor moieties and side chains were inserted. Synthesis and characterization of the systematically varied structural motifs provided insight in structure‐property relationships. Moreover, a dimeric heteroacene was synthesized, and the optoelectronic properties were compared to those of its monomeric counterpart., Functionalized S,N‐heteropentacenes SN5’ comprising annulated thiophene and pyrrole rings with the heteroatom sequence SSNSS in the ladder‐type backbone were developed with systematically varied structural motifs. Tunable frontier orbital energies allowed their application either as donor or as nonfullerenic acceptor in solution‐processed bulk‐heterojunction solar cells.

Understanding the role of metal ions in biology can lead to the development of new catalysts for several industrially important transformations. Lanthanides are the most recent group of metal ions that have been shown to be important in biology, that is, in quinone‐dependent methanol dehydrogenases (MDH). Here we evaluate a literature‐known pyrroloquinoline quinone (PQQ) and 1‐aza‐15‐crown‐5 based ligand platform as scaffold for Ca2+, Ba2+, La3+ and Lu3+ biomimetics of MDH and we evaluate the importance of ligand design, charge, size, counterions and base for the alcohol oxidation reaction using NMR spectroscopy. In addition, we report a new straightforward synthetic route (3 steps instead of 11 and 33 % instead of 0.6 % yield) for biomimetic ligands based on PQQ. We show that when studying biomimetics for MDH, larger metal ions and those with lower charge in this case promote the dehydrogenation reaction more effectively and that this is likely an effect of the ligand design which must be considered when studying biomimetics. To gain more information on the structures and impact of counterions of the complexes, we performed collision induced dissociation (CID) experiments and observe that the nitrates are more tightly bound than the triflates. To resolve the structure of the complexes in the gas phase we combined DFT‐calculations and ion mobility measurements (IMS). Furthermore, we characterized the obtained complexes and reaction mixtures using Electron Paramagnetic Resonance (EPR) spectroscopy and show the presence of a small amount of quinone‐based radical., A pyrroloquinoline quinone (PQQ) based model system was used for the investigation of different factors that may have an impact on the oxidation reaction in the active sites of alcohol dehydrogenase enzymes. Using various metal salts, the influence of ion size and charge, as well as counterions was investigated. The study involves NMR and EPR analysis as well as advanced mass spectrometry techniques.

Large homogeneous and adherent coatings of phenethylammonium bismuth iodide were produced using the cost‐effective and scalable aerosol‐assisted chemical vapor deposition (AACVD) methodology. The film morphology was found to depend on the deposition conditions and substrates, resulting in different optical properties to those reported from their spin‐coated counterparts. Optoelectronic characterization revealed band bending effects occurring between the hybrid material and semiconducting substrates (TiO2 and FTO) due to heterojunction formation, and the optical bandgap of the hybrid material was calculated from UV‐visible and PL spectrometry to be 2.05 eV. Maximum values for hydrophobicity and crystallographic preferential orientation were observed for films deposited on FTO/glass substrates, closely followed by values from films deposited on TiO2/glass substrates., Compact and stable bismuth halide‐based hybrid material thin films were grown using aerosol‐assisted chemical vapor deposition. The dependence of structural and optoelectronic properties of phenethylammonium bismuth iodide films were evaluated on varying substrates, deposition temperatures and curing conditions. The morphology and optical band‐bending effects were related to synthetic parameters, and crack‐free films were obtained with high moisture resistance.

Several phosphaquinodimethanes and their M(CO)5 complexes (M=Cr, Mo, W) and model derivatives have been theoretically investigated regarding the quest of non‐innocence. Computed structural and electronic properties of the P‐Me/NH2 substituted phosphaquinodimethanes and tungsten complexes revealed an interesting non‐innocent ligand behaviour for the radical anion complexes with distonic ion character and a strong rearomatization of the middle phenyl ring. The latter was further probed taking also geometric aromaticity (HOMA) and quinoid distortion parameters (HOMQc) into account, as well as NICS(1). Furthermore, the effect of the P‐substitution was investigated for real (or plausible) complexes and their free ligands focusing on the resulting aromaticity at the middle phenyl ring and vertical one‐electron redox processes. The best picture of ligand engagement in redox changes was provided by representing NICS(1) values versus HOMA and the new geometric distortion parameter HOMQc8., In order to analyze their non‐innocence character when ligated in M(CO)5 complexes, various phosphaquinodimethanes (pPQDM) and their complexes have been theoretically investigated regarding their electronic and structural properties, following corresponding changes in substitution, charge and spin state. Additionally, a combination of computed spin distributions and NICS values with geometric distortion models (HOMA, HOMQc) were used to gain further insights.

The natural product albicidin is a highly potent inhibitor of bacterial DNA gyrase. Its outstanding activity, particularly against Gram‐negative pathogens, qualifies it as a promising lead structure in the search for new antibacterial drugs. However, as we show here, the N‐terminal cinnamoyl moiety of albicidin is susceptible to photochemical E/Z isomerization. Moreover, the newly formed Z isomer exhibits significantly reduced antibacterial activity, which hampers the development and biological evaluation of albicidin and potent derivatives thereof. Hence, we synthesized 13 different variants of albicidin in which the vulnerable para‐coumaric acid moiety was replaced; this yielded photostable analogues. Biological activity assays revealed that diaryl alkyne analogues exhibited virtually undiminished antibacterial efficacy. This promising scaffold will therefore serve as a blueprint for the design of a potent albicidin‐based drug., Lead optimization: The cinnamoyl residue of the antibiotic albicidin is shown to readily undergo UV‐mediated E/Z isomerization, thereby converting from the highly bioactive E form found in the natural product to the significantly less bioactive Z form. Acetylenic replacement of the susceptible methylacrylamide moiety affords a set of photochemically stable albicidin derivatives with virtually undiminished antibacterial activity.

Sensing anionic species in competitive aqueous media is a well‐recognised challenge to long‐term applications across a multitude of fields. Herein, we report a comprehensive investigation of the electrochemical anion sensing performance of novel halogen bonding (XB) and hydrogen bonding (HB) bis‐ferrocene‐(iodo)triazole receptors in solution and at self‐assembled monolayers (SAMs), in a range of increasingly competitive aqueous organic solvent media (ACN/H2O). In solution, the XB sensor notably outperforms the HB sensor, with substantial anion recognition induced cathodic voltammetric responses of the ferrocene/ferrocenium redox couple persisting even in highly competitive aqueous solvent media of 20 % water content. The response to halides, in particular, shows a markedly lower sensitivity to increasing water content associated with a unique halide selectivity at unprecedented levels of solvent polarity. The HB sensor, in contrast, generally displayed a preference towards oxoanions. A significant surface‐enhancement effect was observed for both XB/HB receptive films in all solvent systems, whereby the HB sensor generally displayed larger responses towards oxoanions than its halogen bonding analogue., Redox‐active ferrocenyl receptors enable electrochemical anion sensing in highly competitive aqueous solvent media, with a sensory performance that is markedly dependent on the nature of the non‐covalent interaction. In solution, the halogen bonding sensor (XB) is superior and significantly less sensitive to solvent polarity, while surface immobilisation is associated with an enhanced performance, particularly for the hydrogen bonding (HB) system.

Reported are single crystal SQUID and single crystal high‐frequency/high‐field EPR data of a trinuclear complex with a rare six‐coordinate coordination sphere of a DyIII center coupled to two terminal six‐coordinate NiII ions. The analysis of the single crystal spectroscopic parameters allows for an accurate description of the ground state wavefunction. The experimental analysis is supplemented by the analysis of the paramagnetic NMR spectra, allowing for a thorough description of the DyIII center. The experimental data are interpreted on the basis of an ab initio ligand field analysis, and the computed parameters are in good agreement with the experimental observations. This supports the quality of the theoretical approach based on a pseudo‐spin Hamiltonian for the electronic ground state. Further support emerges from the ab initio ligand field theory based analysis of a structurally very similar system that, in contrast to the complex reported here, shows single molecule magnetic properties, and this is in agreement with the quantum‐chemical prediction and analysis., Discussed is a linear trinuclear DyIIINiII 2 complex with a rare hexacoordinate DyIII center. The magnetic properties were studied experimentally by single crystal SQUID magnetometry, single crystal high‐frequency/high‐field EPR and paramagnetic NMR spectroscopy. Parameters describing the ground state multiplet splitting have also been computed by ab‐initio quantum‐chemical calculations, and the large variety of experimental techniques allows for a thorough validation of the computational analysis.

In the endeavor of extending the clinical use of photodynamic therapy (PDT) for the treatment of superficial cancers and other neoplastic diseases, deeper knowledge and control of the subcellular processes that determine the response of photosensitizers (PS) are needed. Recent strategies in this direction involve the use of activatable and nanostructured PS. Here, both capacities have been tuned in two dendritic zinc(II) phthalocyanine (ZnPc) derivatives, either asymmetrically or symmetrically substituted with 3 and 12 copies of the carbohydrate sialic acid (SA), respectively. Interestingly, the amphiphilic ZnPc‐SA biohybrid (1) self‐assembles into well‐defined nanoaggregates in aqueous solution, facilitating cellular internalization and transport whereas the PS remains inactive. Within the cells, these nanostructured hybrids localize in the lysosomes, as usually happens for anionic and hydrophilic aggregated PS. Yet, in contrast to most of them (e. g., compound 2), hybrid 1 recovers the capacity for photoinduced ROS generation within the target organelles due to its amphiphilic character; this allows disruption of aggregation when the compound is inserted into the lysosomal membrane, with the concomitant highly efficient PDT response., An insightful approach towards activatable and nanostructured photosensitizers has been developed by preparing dendritic biohybrids composed of a core phthalocyanine decorated with multiple sialic acid moieties. The resulting hybrids self‐assemble into well‐defined nanoaggregates in aqueous solution, and disaggregate upon reaching the target organelles, resulting in the on‐site activation of a highly efficient photodynamic response.

The syntheses of bis(triazolium)carbazole precursors and their corresponding coinage metal (Au, Ag) complexes are reported. For alkylated triazolium salts, di‐ or tetranuclear complexes with bridging ligands were isolated, while the bis(aryl) analogue afforded a bis(carbene) AuI‐CNC pincer complex suitable for oxidation to the redox‐stable [AuIII(CNC)Cl]+ cation. Although the ligand salt and the [AuIII(CNC)Cl]+ complex were both notably cytotoxic toward the breast cancer cell line MDA‐MB‐231, the AuIII complex was somewhat more selective. Electrophoresis, viscometry, UV‐vis, CD and LD spectroscopy suggest the cytotoxic [AuIII(CNC)Cl]+ complex behaves as a partial DNA intercalator. In silico screening indicated that the [AuIII(CNC)Cl]+ complex can target DNA three‐way junctions with good specificity, several other regular B‐DNA forms, and Z‐DNA. Multiple hydrophobic π‐type interactions involving T and A bases appear to be important for B‐form DNA binding, while phosphate O⋅⋅⋅Au interactions evidently underpin Z‐DNA binding. The CNC ligand effectively stabilizes the AuIII ion, preventing reduction in the presence of glutathione. Both the redox stability and DNA affinity of the hit compound might be key factors underpinning its cytotoxicity in vitro., Towards new AuIII anticancer agents. Herein a redox‐stabilised DNA‐targeting AuIII bis(carbene) pincer complex with significant cytotoxicity is reported that is likely underpinned by partial DNA intercalation. In silico studies indicate that the complex can also target unusual DNA forms such as 3‐way junctions and Z‐DNA. The structures of several multinuclear AgI complexes discovered en route to the target AuIII complex were also elucidated.

The synthesis of the new bulky vinyllithium reagent (MeIPr=CH)Li, (MeIPr=[(MeCNDipp)2C]; Dipp=2,6‐iPr2C6H3) is reported. This vinyllithium precursor was found to act as a general source of the anionic 2σ, 2π‐electron donor ligand [MeIPr=CH]−. Furthermore, a high‐yielding route to the degradation‐resistant SiII precursor MeIPr⋅SiBr2 is presented. The efficacy of (MeIPr=CH)Li in synthesis was demonstrated by the generation of a complete inorganic divinyltetrelene series (MeIPrCH)2E: (E=Si to Pb). (MeIPrCH)2Si: represents the first two‐coordinate acyclic silylene not bound by heteroatom donors, with dual electrophilic and nucleophilic character at the SiII center noted. Cyclic voltammetry shows this electron‐rich silylene to be a potent reducing agent, rivalling the reducing power of the 19‐electron complex cobaltocene (Cp2Co)., Silylene? NHO Problem! Access to a new lithiated anionic N‐heterocyclic olefin (NHO) yields a complete acyclic divinyltetrelene series.

Single‐molecule force spectroscopy allows investigation of the effect of mechanical force on individual bonds. By determining the forces necessary to sufficiently activate bonds to trigger dissociation, it is possible to predict the behavior of mechanophores. The force necessary to activate a copper biscarbene mechano‐catalyst intended for self‐healing materials was measured. By using a safety line bypassing the mechanophore, it was possible to pinpoint the dissociation of the investigated bond and determine rupture forces to range from 1.6 to 2.6 nN at room temperature in dimethyl sulfoxide. The average length‐increase upon rupture of the Cu−C bond, due to the stretching of the safety line, agrees with quantum chemical calculations, but the values exhibit an unusual scattering. This scattering was assigned to the conformational flexibility of the mechanophore, which includes formation of a threaded structure and recoiling of the safety line., Point break: A latent copper‐biscarbene mechanocatalyst becomes active when a ligand is forcefully removed. Pulling with around 2 nN breaks the copper‐carbon bond, as measured by single‐molecule force spectroscopy. To be able to assign the bond rupture event to the Cu−C bond, mechanophores with two different lengths of safety‐line were specifically synthesized for use in this AFM experiment.

This study demonstrates that chiral‐at‐iron complexes, in which all coordinated ligands are achiral and the overall chirality the consequence of a stereogenic iron center, are capable of catalyzing asymmetric transformations with very high enantioselectivities. The catalyst is based on a previously reported design (J. Am. Chem. Soc. 2017, 139, 4322), in which iron(II) is surrounded by two configurationally inert achiral bidentate N‐(2‐pyridyl)‐substituted N‐heterocyclic carbenes in a C 2‐symmetric fashion and complemented by two labile acetonitriles. By replacing mesityl with more bulky 2,6‐diisopropylphenyl substituents at the NHC ligands, the steric hindrance at the catalytic site was increased, thereby providing a markedly improved asymmetric induction. The new chiral‐at‐iron catalyst was applied to the inverse electron demand hetero‐Diels‐Alder reaction between β,γ‐unsaturated α‐ketoester and enol ethers provide 3,4‐dihydro‐2H‐pyrans in high yields with excellent diastereoselectivities (up to 99 : 1 dr) and excellent enantioselectivities (up to 98 % ee). Other electron rich dienophiles are also suitable as demonstrated for a reaction with a vinyl azide., A chiral‐at‐iron complex, in which all coordinated ligands are achiral and the overall chirality is exclusively due to a stereogenic iron center, catalyzes hetero‐Diels‐Alder reactions with high diastereoselectivities (up to 99 : 1 dr) and enantioselectivities (up to 98 % ee). Key for this excellent stereocontrol are bulky 2,6‐diisopropylphenyl substituents at the N‐heterocyclic carbene ligands which increase the steric hindrance at the catalytic site.

The 9‐ and 12‐dimethylaminophenyl‐substituted berberine derivatives 3 a and 3 b were readily synthesized by Suzuki‐Miyaura reactions and shown to be useful fluorescent probes for the optical detection of quadruplex DNA (G4‐DNA). Their association with the nucleic acids was investigated by spectrometric titrations, CD and LD spectroscopy, and with DNA‐melting analysis. Both ligands bind to duplex DNA by intercalation and to G4‐DNA by terminal π stacking. At neutral conditions, they bind with higher affinity (K b=105−106 M−1) to representative quadruplex forming oligonucleotides 22AG, c‐myc, c‐kit, and a2, than to duplex calf thymus (ct) DNA (K b=5‐7×104 M−1). At pH 5, however, the affinity of 3 a towards G4‐DNA 22AG is higher (K b=1.2×106 M−1), whereas the binding constant towards ct DNA is lower (K b=3.9×103 M−1) than under neutral conditions. Notably, the association of the ligand with DNA results in characteristic changes of the absorption and emission properties under specific conditions, which may be used for optical DNA detection. Other than the parent berberine, the ligands do not show a noticeable increase of their very low intrinsic emission intensity upon association with DNA at neutral conditions. In contrast, a fluorescence light‐up effect was observed upon association to duplex (Φ fl=0.01) and quadruplex DNA (Φ fl=0.04) at pH 5. This fluorimetric response to G4‐DNA association in combination with the distinct, red‐shifted absorption under these conditions provides a simple and conclusive optical detection of G4‐DNA at lower pH., The very weak fluorescence of 4‐dimethylaminophenyl‐substituted berberines only increases significantly if both their conformational flexibility is strongly restricted, i. e. in viscous medium or when bound to quadruplex DNA, and the amino group is protonated at low pH. This requirement of a dual stimulation to cause a light‐up effect enables the spectrometric detection of quadruplex DNA at pH 5.

Bis(1‐(4‐tolyl)‐carboran‐2‐yl)‐(4‐tolyl)‐borane [(1‐(4‐MeC6H4)‐closo‐1,2‐C2B10H10‐2‐)2(4‐MeC6H4)B] (1), a new bis(o‐carboranyl)‐(R)‐borane was synthesised by lithiation of the o‐carboranyl precursor and subsequent salt metathesis reaction with (4‐tolyl)BBr2. Cyclic voltammetry experiments on 1 show multiple distinct reduction events with a one‐electron first reduction. In a selective reduction experiment the corresponding paramagnetic radical anion 1.− was isolated and characterized. Single‐crystal structure analyses allow an in‐depth comparison of 1, 1.−, their calculated geometries, and the S1 excited state of 1. Photophysical studies of 1 show a charge transfer (CT) emission with low quantum yield in solution but a strong increase in the solid state. TD‐DFT calculations were used to identify transition‐relevant orbitals., Stabilization via three‐coordinate boron allows the isolation of a paramagnetic radical anion of ortho‐carborane. A photophysical, electrochemical and crystallographic study backed by DFT calculations shines light on closo‐nido intermediate structures, charge transfer processes and electron accepting ability.

A facile imide coupling strategy for the one‐step preparation of G‐quadruplex ligands with varied core chemistries is described. The G‐quadruplex stabilization of a library of nine compounds was examined using FRET melting experiments, and CD, UV‐Vis, fluorescence and NMR titrations, identifying several compounds that were capable of stabilizing G‐quadruplex DNA with interesting selectivity profiles. The best G4 ligand was identified as compound 3, which was based on a perylene scaffold and exhibited 40‐fold selectivity for a telomeric G‐quadruplex over duplex DNA. Surprisingly, a tetra‐substituted flexible core, compound 11, also exhibited selective stabilization of G4 DNA over duplex DNA. The anticancer and antiparasitic activity of the library was also examined, with the lead compound 3 exhibiting nanomolar inhibition of Trypanosoma brucei with 78‐fold selectivity over MRC5 cells. The cellular localization of this compound was also studied via fluorescence microscopy. We found that uptake was time dependant, with localization outside the nucleus and kinetoplast that could be due to strong fluorescence quenching in the presence of small amounts of DNA., The rigid rules of G‐quadruplex stabilization: A library of amphiphiles has been synthesized in one step, using a simple imide condensation reaction. The G‐quadruplex stabilization, anti‐cancer and anti‐parasitic activity of the library has been investigated, uncovering the important factors that govern G‐quadruplex binding and selectivity, yielding a promising new core‐motif and a compound with potent trypanosomacidal activity.

Strongly Lewis acidic cationic aluminium complexes, stabilized by β–diketiminate (BDI) ligands and free of Lewis bases, have been prepared as their B(C6F5)4 − salts and were investigated for catalytic activity in imine hydrogenation. The backbone (R1) and N (R2) substituents on the R1,R2BDI ligand (R1,R2BDI=HC[C(R1)N(R2)]2) influence sterics and Lewis acidity. Ligand bulk increases along the row Me,DIPPBDI, A series of strongly Lewis acidic cationic aluminium complexes, stabilized by β–diketiminate (BDI) ligands and free of Lewis bases, have been prepared as their B(C6F5)4 − salts. Their catalytic activity in imine hydrogenation depends strongly on the substituents in the BDI ligand. DFT calculations on the mechanism reveal two interconnected catalytic cycles. Hydrogen is activated either by Al⋅⋅⋅imine or Al⋅⋅⋅amine Frustrated‐Lewis‐Pairs.

The dauc‐8‐en‐11‐ol synthase from Streptomyces venezuelae was investigated for its catalytic activity towards alternative terpene precursors, specifically designed to enable new cyclisation pathways. Exchange of aromatic amino acid residues at the enzyme surface by site‐directed mutagenesis led to a 4‐fold increase of the yield in preparative scale incubations, which likely results from an increased enzyme stability instead of improved enzyme kinetics., Daucenol Synthase (DcS) from Streptomyces venezuelae was redirected using substrate analogues with additional, shifted, or lacking methyl groups to yield molecules from a naturally difficult to access chemical space, and improved in its catalytic efficiency through site‐directed mutagenesis of surface residues, turning DcS into a high yielding biocatalyst.

Defect engineering and metal encapsulation are considered as valuable approaches to fine‐tune the reactivity of metal–organic frameworks. In this work, various MOF‐808 (Zr) samples are synthesized and characterized with the final aim to understand how defects and/or platinum nanoparticle encapsulation act on the intrinsic and reactive properties of these MOFs. The reactivity of the pristine, defective and Pt encapsulated MOF‐808 is quantified with water adsorption and CO2 adsorption calorimetry. The results reveal strong competitive effects between crystal morphology and missing linker defects which in turn affect the crystal morphology, porosity, stability, and reactivity. In spite of leading to a loss in porosity, the introduction of defects (missing linkers or Pt nanoparticles) is beneficial to the stability of the MOF‐808 towards water and could also be advantageously used to tune adsorption properties of this MOF family., Defects and metal nanoparticle encapsulations have been shown to have significant impacts on structure, texture, morphology and reactivity of the synthesized MOFs. Control over defects creation and metal nanoparticle encapsulations can become useful avenues to adjust the properties of MOFs.

Syntheses of the copper and gold complexes [Cu{Fe(CO)5}2][SbF6] and [Au{Fe(CO)5}2][HOB{3,5‐(CF3)2C6H3}3] containing the homoleptic carbonyl cations [M{Fe(CO)5}2]+ (M=Cu, Au) are reported. Structural data of the rare, trimetallic Cu2Fe, Ag2Fe and Au2Fe complexes [Cu{Fe(CO)5}2][SbF6], [Ag{Fe(CO)5}2][SbF6] and [Au{Fe(CO)5}2][HOB{3,5‐(CF3)2C6H3}3] are also given. The silver and gold cations [M{Fe(CO)5}2]+ (M=Ag, Au) possess a nearly linear Fe‐M‐Fe’ moiety but the Fe‐Cu‐Fe’ in [Cu{Fe(CO)5}2][SbF6] exhibits a significant bending angle of 147° due to the strong interaction with the [SbF6]− anion. The Fe(CO)5 ligands adopt a distorted square‐pyramidal geometry in the cations [M{Fe(CO)5}2]+, with the basal CO groups inclined towards M. The geometry optimization with DFT methods of the cations [M{Fe(CO)5}2]+ (M=Cu, Ag, Au) gives equilibrium structures with linear Fe‐M‐Fe’ fragments and D 2 symmetry for the copper and silver cations and D 4d symmetry for the gold cation. There is nearly free rotation of the Fe(CO)5 ligands around the Fe‐M‐Fe’ axis. The calculated bond dissociation energies for the loss of both Fe(CO)5 ligands from the cations [M{Fe(CO)5}2]+ show the order M=Au (D e=137.2 kcal mol−1)>Cu (D e=109.0 kcal mol−1)>Ag (D e=92.4 kcal mol−1). The QTAIM analysis shows bond paths and bond critical points for the M−Fe linkage but not between M and the CO ligands. The EDA‐NOCV calculations suggest that the [Fe(CO)5]→M+←[Fe(CO)5] donation is significantly stronger than the [Fe(CO)5]←M+→[Fe(CO)5] backdonation. Inspection of the pairwise orbital interactions identifies four contributions for the charge donation of the Fe(CO)5 ligands into the vacant (n)s and (n)p AOs of M+ and five components for the backdonation from the occupied (n‐1)d AOs of M+ into vacant ligand orbitals., Donation of an electron pair from the HOMO of [Fe(CO)5]2 to the 4s LUMO of Cu+ giving the (+,+) component of the Fe‐Cu‐Fe σ bond in [Cu{Fe(CO)5}2]+. The associated charge flow with the direction red→blue is given by the deformation density.

Serotonin, an important signaling molecule in humans, has an unexpectedly high lipid membrane affinity. The significance of this finding has evoked considerable speculation. Here we show that membrane binding by serotonin can directly modulate membrane properties and cellular function, providing an activity pathway completely independent of serotonin receptors. Atomic force microscopy shows that serotonin makes artificial lipid bilayers softer, and induces nucleation of liquid disordered domains inside the raft‐like liquid‐ordered domains. Solid‐state NMR spectroscopy corroborates this data at the atomic level, revealing a homogeneous decrease in the order parameter of the lipid chains in the presence of serotonin. In the RN46A immortalized serotonergic neuronal cell line, extracellular serotonin enhances transferrin receptor endocytosis, even in the presence of broad‐spectrum serotonin receptor and transporter inhibitors. Similarly, it increases the membrane binding and internalization of oligomeric peptides. Our results uncover a mode of serotonin–membrane interaction that can potentiate key cellular processes in a receptor‐independent fashion., It is known that serotonin binds to lipid membranes with high affinity, but what does it do to it? We find that it makes artificial lipid bilayers softer and easier to indent by an AFM tip (top), and promotes disorder in ordered regions. For cell membranes, this effect facilitates increased endocytosis (bottom). This increase occurs even when the serotonin receptors are blocked, providing a receptor‐independent pathway for serotonin action.

As sulfur‐containing organic molecules thioamides and their isomers are conceivable intermediates in prebiotic chemistry, for example, in the formation of amino acids and thiazoles and resemble viable candidates for detection in interstellar media. Here, we report the characterization of parent thioformamide in the solid state via single‐crystal X‐ray diffraction and its photochemical interconversion to its hitherto unreported higher energy tautomer thiolimine in inert argon and dinitrogen matrices. Upon photogeneration, four conformers of thiolimine form, whose ratio depends on the employed wavelength. One of these conformers interconverts due to quantum mechanical tunneling with a half‐life of 30–45 min in both matrix materials at 3 and 20 K. A spontaneous reverse reaction from thiolimine to thioformamide is not observed. To support our experimental findings, we explored the potential energy surface of the system at the AE‐CCSD(T)/aug‐cc‐pCVTZ level of theory and computed tunneling half‐lives with the CVT/SCT approach applying DFT methods., Keep it simple! Thioamides resemble viable prebiotic building blocks for biologically relevant molecules. However, only a handful of experimental reports on parent thioformamide exist. X‐ray diffraction data of thioformamide are reported and its tautomerization induced by UV irradiation under cryogenic conditions is presented. Four conformers of the corresponding thiolimine form, whose (tunneling) reactivity is investigated.

The detection of multiply charged helium droplet anions is reported for the first time. By ionizing droplets of superfluid helium with low energy electrons (up to 25 eV), it was possible to produce droplets containing up to five negative charges, which remain intact on the timescale of the experiment. The appearance sizes for different charge states are determined and are found to be orders of magnitude larger than for the equivalent cationic droplets, starting at 4 million He atoms for dianions. Droplets with He*− as charge carriers show signs of being metastable, but this effect is quenched by the pickup of water molecules., Charged droplets: The detection of multiply charged helium droplet anions is reported for the first time. By ionizing droplets of superfluid helium with low energy electrons (up to 25 eV), it was possible to produce droplets containing up to five negative charges, which remain intact on the timescale of the experiment.

Perylene‐ as well as naphthalenediimides were fused to hexabenzocoronenes (HBCs) at their imide position to realize highly π‐extended donor–acceptor (D–A)‐hybrids. Successful isomer separation in the first step was decisive to guarantee a straightforward synthetic sequence. Hexaphenylbenzenes as precursors were accessed via Diels–Alder reactions and reacted in a Scholl oxidation to yield the respective HBC derivatives. The fully conjugated benzimidazole linker, which separates the electron donating HBC from the electron accepting rylenediimide, enabled the formation of either a linear or a helical configuration. Largely different chemical, physical, and optoelectrical characteristics were noted for the two configurations. What stood out was their aggregation and their excited state deactivation depending on the solvent polarity. Results from global analysis of the femtosecond transient absorption data corroborated the formation of a charge‐transfer (CT) state that is stabilized in the helically fused configuration relative to the linear analogue. However, a comparison with spectroelectrochemical experiments failed to disclose evidence for a charge‐separated (CS) state., Fantastic fusion: The fusion of naphthalene‐ as well as perylenediimides and hexabenzocoronenes via a fully conjugated benzimidazole linker enables the formation of helical as well as linear π‐extended donor–acceptor‐hybrids applying Diels–Alder and Scholl‐type chemistry. Remarkable differences in aggregation, charge‐transfer (CT) stabilization as well as CT lifetimes emphasize the influence of the configuration of the bridge on donor–acceptor properties.