The crystal structure of form 4 of the drug 4-[4-(2-adamantylcarbamoyl)-5-tert-butyl-pyrazol-1-yl]benzoic acid is determined using a protocol for NMR powder crystallography at natural isotopic abundance combining solid-state (1)H NMR spectroscopy, crystal structure prediction, and density functional theory chemical shift calculations. This is the first example of NMR crystal structure determination for a molecular compound of previously unknown structure, and at 422 g/mol this is the largest compound to which this method has been applied so far.

Oxidation of the spirocyclic oxindole derivative, isamic acid 1, led to decarboxylation and ring expansion to quinazolino[4,5-b]quinazoline-6,8-dione 7 rather than, as previously believed, its isomer 6. The structure of 7 was confirmed by X-ray crystallography. Condensation of isatin (indole-2,3-dione) and 2-aminobenzamide led to the spirocyclic molecule, spiro[3H-indole-3,2′(1H)quinazoline]-2,4′(1H,3H)dione 8, which was also identified as an intermediate in the oxidation of isamic acid. Mild hydrolysis of 7 gave the 10-membered molecule 22. Isamic acid could easily be converted to N-nitrosoisamic acid, which when heated in ethanol underwent a ring expansion to a hydroximino derivative, 38, of compound 6. The structure of 38 was confirmed by X-ray crystallography.

Solubility is a frequently recurring issue within pharmaceutical industry, and new methods to proactively resolve this are of fundamental importance. Here, a novel methodology is reported for intrinsic solubility improvement, using in silico prediction of crystal structures, by perturbing key interactions in the crystalline solid state. The methodology was evaluated with a set of benzodiazepine molecules, using the two‐dimensional molecular structure as the only a priori input. The overall trend in intrinsic solubility was correctly predicted for the entire set of benzodiazepines molecules. The results also indicate that, in drug compound series where the melting point is relatively high (i.e., “brick dust” compounds), the reported methodology should be very suitable for identifying strategically important molecular substitutions to improve solubility. As such, this approach could be a useful predictive tool for rational compound design in the early stages of drug development.

A new redox couple, [Cu(bpye)2]+/2+, has been synthesized, and applied in dye-sensitized solar cells (DSSCs). Overall efficiencies of 9.0% at 1 sun and 9.9% at 0.5 sun were obtained, which are considerably higher than those obtained for cells containing the reference redox couple, [Co(bpy)3]2+/3+. These results represent a record for copper-based complex redox systems in liquid DSSCs. Fast dye regeneration, sluggish recombination loss processes, faster electron self-exchange reactions and suitable redox potentials are the main reasons for the observed increase in efficiency. In particular, the main disadvantage of cobalt complex-based redox couples, charge-transport problems, appears to be resolved by a change to copper complex redox couples. The results make copper complex-based redox couples very promising for further development of highly efficient DSSCs.

Lithium-ion-free tris(2,2′-bipyridine) Co(ii/iii)-mediated electrolytes have previously been proposed for long-term stable dye-sensitized solar cells (DSSCs). Such redox systems also offer an impressive DSSC performance improvement under light soaking exposure, manifested by an increase in photocurrent and fill factor without the expense of decreasing photovoltage. Kinetic studies show that charge transfer and ion diffusion at the electrode/electrolyte interface are improved due to the light exposure. Control experiments reveal that the light effect is unambiguously associated with electrolyte components, [Co(bpy)3]3+ and the Lewis-base additive tert-butylpyridine (TBP). Electrochemical and spectroscopic investigation of the [Co(bpy)3]3+/TBP mixtures points out that the presence of TBP, which retards the electrolyte diffusion, however causes an irreversible redox reaction of [Co(bpy)3]3+ upon light exposure that improves the overall conductivity. This discovery not only provides a new strategy to mitigate the typical Jsc-Voc trade-off in Co(ii/iii)-mediated DSSCs but also highlights the importance of investigating the photochemistry of a photoelectrochemical system. 

The precipitation of solid compounds from model electrolytes for liquid dye-sensitized solar cells has a story to tell regarding decomposition processes to be expected in such systems. Of course, the crystal lattice energy for a specific crystalline compounds plays a role in what compound that will eventually precipitate, but the compounds nevertheless serve as indicators for what type of processes that take place in the solar cell electrolytes upon ageing. From the compounds isolated in this study we learn that both ligand exchange processes, double-salt precipitation and oxidation are degradation processes that should not be overlooked when formulating efficient and stable electrolytes for this type of electrochemical system.

This study focused on the mechanistic interpretation of ex vivo oxidation of a candidate drug in blood plasma samples. An unexpected lipid peroxide-mediated epoxidation followed by a dramatic rearrangement led to production of a five-membered oxazole derivative from the original six-membered pyrazinone-carboxamide core of a human neutrophil elastase inhibitor, 6-(1-(4-cyanophenyl)-1H-pyrazol-5-yl)-N-ethyl-5-methyl-3-oxo-4-(3-(trifluoromethyl)phenyl)-3,4-dihydropyrazine-2-carboxamide (AZD9819). The rearranged oxidation product 2-(1-(4-cyanophenyl)-1H-pyrazol-5-yl)-5-(N-ethylacetamido)-N-(3-(trifluoromethyl)phenyl)oxazole-4-carboxamide was characterized by accurate-mass tandem mass spectrometry fragmentations, by two-dimensional NMR and X-ray crystallography of an authentic standard, and by incorporation of an (18)O atom from molecular (18)O2 to the location predicted by our proposed mechanism. The lipid peroxide-mediated oxidation was demonstrated by using human low-density lipoprotein (LDL) in pH 7.4 phosphate buffer and by inhibiting the oxidation with ascorbic acid or l-glutathione, two antioxidants effective in both plasma and the LDL incubation. A nucleophilic mechanism for the epoxidation of AZD9819 by lipid hydroperoxides explains the prevention of its ex vivo oxidation by acidification of the plasma samples. The discovery of the lipid peroxide-dependent oxidation of an analyte and the means of prevention could provide valuable information for biotransformation and bioanalysis.

Glioblastoma remains an incurable brain cancer. Drugs developed in the past 20 years have not improved the prognosis for patients, necessitating the development of new treatments. We have previously reported the therapeutic potential of the quinoline methanol Vacquinol-1 (1) that targets glioblastoma cells and induces cell death by catastrophic vacuolization. Compound 1 is a mixture of four stereoisomers due to the two adjacent stereogenic centers in the molecule, complicating further development in the preclinical setting. This work describes the isolation and characterization of the individual isomers of 1 and shows that these display stereospecific pharmacokinetic and pharmacodynamic features. In addition, we present a stereoselective synthesis of the active isomers, providing a basis for further development of this compound series into a novel experimental therapeutic for glioblastoma.

2,2′-Biindolyl has been condensed with aromatic and aliphatic aldehydes and products featuring 10-membered rings have been obtained. Thus, benzaldehyde gave compound 24a as the primary product, which readily underwent transannular oxidative coupling to 25a. The structures of both compounds were confirmed by X-ray crystallography. The product from 2,2′-biindolyl and formaldehyde under strongly acidic conditions was slightly different leading to compound 11, whose structure also was confirmed by X-ray crystallography. In this case, two molecules of 2,2′-biindolyl reacted with six molecules of formaldehyde.

In contribution to the pharmaceutical development of cyclic guanosine monophosphorothioate analogue cGMPSA as a potential active pharmaceutical ingredient (API) for the treatment of inherited retinal degenerations (IRDs), its neutral form (cGMPSA-H) and salts of sodium (-Na), calcium (-Ca), ammonium (-NH4), triethylammonium (-TEA), tris(hydroxymethyl)aminomethane (-Tris), benethamine (-Bnet), and benzathine (-BZ) were prepared. Their solid-state properties were studied with differential scanning calorimetry, thermogravimetric analysis, hot-stage microscopy, and dynamic vapor sorption, and their solubilities were measured in deionized H2O as well as aqueous HCl and NaOH buffers. A total of 21 crystal modifications of cGMPSA were found and characterized by X-ray powder diffraction. Despite their crystalline character, no API forms featured any observable melting points during thermal analyses and instead underwent exothermic decomposition at ≥163 °C. Both the vapor sorption behavior and solubility were found to differ significantly across the API forms. cGMPSA-BZ featured the lowest aqueous solubility and hygroscopicity, with 50 μg/mL and 5 % mass gain at maximum relative humidity. The synthesis and crystallization of some crystal modifications were upscaled to >10 g. Single crystal X-ray diffraction was performed which resulted in the first crystal structure determination and absolute configuration of a cyclic guanosine monophosphorothioate, confirming the RP- conformation at the phosphorus atom. 

A multiresponsive enamine-based molecular switch is presented, in which forward/backward configurational rotation around the C=C bond could be precisely controlled by the addition of an acid/base or metal ions. Fluorescence turn-on/off effects and large Stokes shifts were observed while regulating the switching process with CuII. The enamine functionality furthermore enabled double dynamic regimes, in which configurational switching could operate in conjunction with constitutional enamine exchange of the rotor part. This behavior was used to construct a prototypical dynamic covalent switch system through enamine exchange with primary amines. The dynamic exchange process could be readily turned on/off by regulating the switch status with pH.

The biologically active Michael acceptor 2-methylene-3-quinuclidinone (MQ) has a unique chemical reactivity and forms several products upon dissolution in water. With the use of X-ray, NMR and LCMS data the structures of two previously incorrectly characterised compounds are rectified. A complex equilibrium in water, containing novel dimeric species of MQ, and its dependence on temperature, pH and concentration is presented.

We report the significant role of synthetic routes and the importance of     solvents in the synthesis of org.-inorg. lead iodide materials.  Through     one route, the intercalation of DMF in the crystal structure was obsd.     leading to a one--dimensional (1D) [NH3(CH2)4NH3]Pb2I6 structure of the     product.  This product was compared with the two-dimensional (2D)     [NH3(CH2)4NH3]PbI4 recovered from aq. solvent based synthesis with the     same precursors.  UV-visible absorption spectroscopy showed a red-shift of     0.1 eV for the band gap of the 1D network in relation to the 2D system.     This shift primarily originates from a shift in the valence band edge as     detd. from photoelectron- and X-ray spectroscopy results.  These findings     also suggest the iodide 5p orbital as the principal component in the d. of     states in the valence band edge.  Single crystal data show a change in the     local coordination around iodide, while in both materials, lead atoms are     surrounded by iodide atoms in octahedral units.  The cond. of the     one-dimensional material ([NH3(CH2)4NH3]Pb2I6) was 50% of the     two-dimensional material ([NH3(CH2)4NH3]PbI4).  The fabricated solar cells     reflect these changes in the chem. and electronic structure of both     materials, although the total light conversion efficiencies of solar cells based on both products were similar.

The synthetic route and properties of three 2D hybrid organic/inorganic lead iodide perovskite materials are reported. The 2D perovskites were synthesized from the reaction between PbI₂and the di-cations of 1,4-diaminobutane, 1,6-diaminohexane, and 1,8-diaminooctane. The resulting products were [NH₃(CH₂)₄NH₃]PbI₄ (BdAPbI₄), [NH₃(CH₂)₆NH₃]PbI₄ (HdAPbI₄), and [NH₃(CH₂)₈NH₃]PbI₄ (OdAPbI₄). Structural characterization shows that two dimensional perovskite structures were formed with inorganic structural planes separated by organic layers. Absorption spectra show band gaps of 2.37 eV (BdAPbI₄), 2.44 eV (HdAPbI₄), and 2.55 eV (OdAPbI₄). The 2D perovskite materials were investigated as light absorbing materials in solid state solar cells. The best performing material under moist, ambient conditions was BdAPbI₄(1.08% efficiency), which was comparable to methylammonium Pb(II) iodide (MAPbI₃) solar cells (2.1% efficiency) manufactured and studied under analogous conditions. When compared to MAPbI₃, the 2D materials have larger band gaps and lower photoconductivity, while BdAPbI₄based solar cells shows a comparable absorbed photon-to-current efficiency as compared toMAPbI₃ based ones.

Currently, there is a strong need to accelerate development of systematic and robotized procedures for discovery of photovoltaic materials in order to aid the transition toward the use of clean and sustainable energy sources. Perovskite-type materials represent a broad class of compounds that have recently attracted great interest for application as photovoltaic materials. Such materials offer a vast chemical and structural space, qualifying them as an interesting starting point for further exploration using robotized screening methods. In this work, the development and application of a robotized procedure for the screening and solar cell characterization of perovskite-inspired materials is presented. Several combinations of cationic dyes and metal halides were examined by using a fully automated robotic screening cycle, including solar cell characterization based on triple mesoscopic solar cell devices. It is shown that the presented methodology is promising for the detection of new photovoltaic materials, which is demonstrated by the discovery of a selection of photovoltaic candidates. Some of the discovered candidates, for instance [QR][PbI3], were further characterized theoretically and experimentally. 

In this work, we present the ionic liquid (IL) synthesis of two novel pseudo-2D perovskite-type gold(III)polyiodide compounds, [DodMe2S][AuI4][I3] (1) and [Et3S][AuI4][I5] (2), and their application as active layers in monolithic solar cells. The compounds are composed of tetraiodoaurate anions and polyiodide entities, infinite polyiodide chains in 1 and pentaiodides in 2, which display short intermolecular contacts resulting in relatively small electronic bandgaps. This work represents the first demonstration of film deposition of gold iodide/polyiodide compounds onto porous monolithic substrates with subsequent solar cell characterization. The devices show promising photovoltaic performance and could unlock new materials design possibilities, ultimately moving away from lead-based photovoltaic materials. These findings further highlight the use of simple polyiodide entities to increase the structural and electronic dimensionality of gold perovskite-type anions. © 2023 The Authors. 

Low-dimensional hybrid perovskite materials offer significantly improved stability as well as an extensive compositional space to explore. However, they suffer from poor photovoltaic performance as compared to the 3D perovskite materials because of poor charge-transport properties. Herein, we present the concept of internal dye-sensitized hybrid perovskite compounds involving five novel low-dimensional perovskite-type materials 1-5 incorporating triarylmethane, phenazinium and near-IR (NIR) cyanine cationic dyes, resp. The synthesis characterization and theor. anal. of these compounds are presented. Theor. calculations provide interesting insights into the effects of these dyes on the band structure of the low-dimensional anionic metal-halides and especially highlight compound 1 as a promising photovoltaic candidate. Solar cell investigation of devices based on 1 were conducted. The results show an average power conversion efficiency (PCE) of about 0.1%, which is among the highest reported for a 1D material despite the use of undoped Spiro-OMeTAD as the hole-transport material (HTM). Incident photon-to-electron efficiency (IPCE) spectra confirm the contribution of the dye to the overall photocurrent of the solar cell. Moreover, examination of solar cell devices based on the bismuth-based compound 5 resulted in PCEs in the range of 0.1%. This illustrates the potential of this concept to be exploited for lead-free photovoltaics. Finally automated robotized screening of low-dimensional hybrid perovskite materials through the screening robot PROTEUS has emerged as a powerful tool in the search for novel perovskite-like materials. Our work highlights that the use of cationic dyes could induce interesting sensitizing properties to low-dimensional metal-halide chains and may therefore provide inspiration and new design strategies for the synthesis of new lead-free photovoltaic materials.

Two new organic–inorganic hybrid perovskite compounds, (Me₃S)₂Pb₅I₁₄*2I₂ (1) and (C₈H₁₁S)₂Pb₂I₆*I₂ (2), have been synthesized and subsequently characterized in this study. The materials were synthesized from facile one-pot, one-step reactions of lead iodide, corresponding sulfide, methanol, iodine, and hydroiodic acid in the case of 2. Structural analysis reveals the presence of polyiodide entities in both compounds. Compound 1 contains triiodide anions, I₃^–, that are uniquely shared between the 2D inorganic slabs, forming a 3D network. Both 1 and 2 have I₂ molecules that are bridging the inorganic slabs through a structural motif that can be regarded as a tetraiodide anion, I₄^2–. Optical spectroscopy shows band gaps of 1.86 eV for 1 and 1.89 eV for 2. The optoelectronic properties were further investigated with band structure calculations. Single-crystal IV-characteristics of 1 show that the compound is photoactive confirming it as a promising photovoltaic candidate. Compound 1 highlights a novel strategy of designing 3D semiconducting hybrid materials by incorporating polyiodides to provide direct geometric and electronic connections between the semiconducting inorganic perovskite sheets.

The compound (Et3S)[Ag4I5], 1, is readily synthesized from room-temperature, ionic-liquid media and displays a complex network structure of Ag6I6 cages with Ag22+ pairs forming 1D-chains linked into layers distinctly separate from the disordered sulphonium cations. The compound should be regarded as a large-bandgap semiconductor, but its significant structural voids qualify the compound a candidate for optoelectronic applications through the inclusion of suitable guest molecules. © 2020 The Authors. 

A fast transition towards the use of clean and green energy sources requires accelerated discovery of new energy storage systems and devices. In this concept automation and robotics can play a key role. Here we present the development of a robotized platform, Poseidon, for the screening and discovery of new water-based electrolyte candidate systems for lithium-ion batteries (LIBs) systems. We have successfully demonstrated the Poseidon screening and characterisation capabilities for electrolytic discovery, which includes a range of steps such as electrolyte formulation, Raman spectroscopic characterization, coin-cell mounting/disassembling and electrochemical battery evaluation via an accelerated screening cycling procedure. A comparison with analogous manual laboratory experiments shows that relevant accuracy for robotized screening purposes has been established. Furthermore, the presented accelerated charge/discharge cycling procedure is shown to be adequate for screening purposes of the test system. © 2022 The Authors

The water-in-salt electrolytes have promoted aqueous Li-ion batteries to become one of the most promising candidates to overcome safety concerns/issues of traditional Li-ion batteries. A simple increase of Li-salt concentration in electrolytes can successfully expand the electrochemical stability window of aqueous electrolytes beyond 2 V. However, necessary stability improvements require an increase in complexity of the ternary electrolytes. Here, we have explored the effects of novel, Gemini-type ionic liquids (GILs) as a co-solvent systems in aqueous Li[TFSI] mixtures and investigated the transport properties of the resulting electrolytes, as well as their electrochemical performance. The devices containing pyrrolidinium-based GILs show superior cycling stability and promising specific capacity in the cells based on the commonly used electrode materials LTO (Li4Ti5O12) and LMO (LiMn2O4). © 2023, The Author(s).

Water-in-salt electrolytes (WISEs) have expanded the useful electrochemical stability of water, making the development of functional aqueous lithium-ion batteries more accessible. The implementation of additives in the formulation of WISEs can further improve the electrochemical stability of water and avoid potential lithium-ion salt solubility issues. Here, we have used Gemini-type ionic liquids to suppress water activity by designing the structure of ionic-liquid cations. The different water-organizing effects of ionic-liquid cations have been investigated and correlated to battery performance in LTO/LMO full cells. The champion device, containing the most chaotropic ionic liquid, retained at least 99% of its Coulombic efficiency after 500 charging cycles, associated with a final specific discharge capacity of 85 mA h·g-1. These results indicated that water-rich Li+ solvation shells significantly contribute to the excellent device performance and long-term stability of the LTO/LMO-based full battery cells. This work shows that the fine-tuning of the Li+ solvation shell and water structure by the addition of chaotropic cations represents a promising strategy for generating more stable and effective lithium-ion-containing rechargeable aqueous batteries. 

Battery cell assembly and testing in conventional battery research is acknowledged to be heavily time-consuming and often suffers from large cell-to-cell variations. Manual battery cell assembly and electrolyte formulations are prone to introducing errors which confound optimization strategies and upscaling. Herein we present ODACell, an automated electrolyte formulation and battery assembly setup, capable of preparing large batches of coin cells. We demonstrate the feasibility of Li-ion cell assembly in an ambient atmosphere by preparing LiFePO4‖Li4Ti5O12-based full cells with dimethyl sulfoxide-based model electrolyte. Furthermore, the influence of water is investigated to account for the hygroscopic nature of the non-aqueous electrolyte when exposed to ambient atmosphere. The reproducibility tests demonstrate a conservative fail rate of 5%, while the relative standard deviation of the discharge capacity after 10 cycles was 2% for the studied system. The groups with 2 vol% and 4 vol% of added water in the electrolyte showed overlapping performance trends, highlighting the nontrivial relationship between water contaminants in the electrolytes and the cycling performance. Thus, reproducible data are essential to ascertain whether or not there are minor differences in the performance for high-throughput electrolyte screenings. ODACell is broadly applicable to coin cell assembly with liquid electrolytes and therefore presents an essential step towards accelerating research and development of such systems.