A broadband online X-ray spectrometer has been designed and commissioned at the SUD beamline of the Shanghai Soft X-ray Free-Electron Laser Facility, which can deliver both SASE and seeded FEL pulses to user experiments, spanning the photon energy range of 50–620 eV. The resolving powers of the spectrometer calibrated via online measurement at 92 eV and 249 eV are ∼20000 and ∼15000, respectively, and the absolute photon energy is characterized by an electron time-of-flight spectrometer. The high energy resolution provided by the spectrometer can differentiate the fine structure in the FEL spectrum, to determine its pulse length.

In-vacuum undulators (IVUs), which have become an essential tool in synchrotron radiation facilities, have two technical challenges toward further advancement: one is a strong attractive force between top and bottom magnetic arrays, and the other is a stringent requirement on magnetic materials to avoid demagnetization. The former imposes a complicated design on mechanical and vacuum structures, while the latter limits the possibility of using high-performance permanent magnets. To solve these issues, a number of technical developments have been made, such as force cancellation and modularization of magnetic arrays, and enhancement of resistance against demagnetization by means of a special magnetic circuit. The performance of a new IVU built upon these technologies has revealed their effectiveness for constructing high-performance IVUs in a cost-effective manner.

The Pohang Accelerator Laboratory X-ray Free-Electron Laser (PAL-XFEL) operates hard X-ray and soft X-ray beamlines for conducting scientific experiments providing intense ultrashort X-ray pulses based on the self-amplified spontaneous emission (SASE) process. The X-ray free-electron laser is characterized by strong pulse-to-pulse fluctuations resulting from the SASE process. Therefore, online photon diagnostics are very important for rigorous measurements. The concept of photo-absorption and emission using solid materials is seldom considered in soft X-ray beamline diagnostics. Instead, gas monitoring detectors, which utilize the photo-ionization of noble gas, are employed for monitoring the beam intensity. To track the beam position at the soft X-ray beamline in addition to those intensity monitors, an X-ray ionization beam position monitor (XIBPM) has been developed and characterized at the soft X-ray beamline of PAL-XFEL. The XIBPM utilizes ionization of either the residual gas in an ultra-high-vacuum environment or injected krypton gas, along with a microchannel plate with phosphor. The XIBPM was tested separately for monitoring horizontal and vertical beam positions, confirming the feasibility of tracking relative changes in beam position both on average and down to single-shot measurements. This paper presents the basic structure and test results of the newly developed non-invasive XIBPM.

A 1D imaging soft X-ray spectrometer installed on the small quantum systems (SQS) scientific instrument of the European XFEL is described. It uses movable cylindrical constant-line-spacing gratings in the Rowland configuration for energy dispersion in the vertical plane, and Wolter optics for simultaneous 1D imaging of the source in the horizontal plane. The soft X-ray fluorescence spectro-imaging capability will be exploited in pump–probe measurements and in investigations of propagation effects and other nonlinear phenomena.

The paper considers the possibility of using the diamond-silicon carbide composite Skeleton® with a technological coating of polycrystalline silicon as a substrate for X-ray mirrors used with powerful synchrotron radiation sources (third+ and fourth generation). Samples were studied after polishing to provide the following surface parameters: root-mean-square flatness ≃ 50 nm, micro-roughness on the frame 2 µm × 2 µm σ ≃ 0.15 nm. The heat capacity, thermal conductivity and coefficient of linear thermal expansion were investigated. For comparison, a monocrystalline silicon sample was studied under the same conditions using the same methods. The value of the coefficient of linear thermal expansion turned out to be higher than that of monocrystalline silicon and amounted to 4.3 × 10−6 K−1, and the values of thermal conductivity (5.0 W cm−1 K−1) and heat capacity (1.2 J K−1 g−1) also exceeded the values for Si. Thermally induced deformations of both Skeleton® and monocrystalline silicon samples under irradiation with a CO2 laser beam have also been experimentally studied. Taking into account the obtained thermophysical constants, the calculation of thermally induced deformation under irradiation with hard (20 keV) X-rays showed almost three times less deformation of the Skeleton® sample than of the monocrystalline silicon sample.

The split-and-delay unit (SDU) at FLASH2 will be upgraded to enable the simultaneous operation of two temporally, spatially and spectrally separated probe beams when the free-electron laser undulators are operated in a two-color scheme. By means of suitable thin filters and an optical grating beam path a wide range of combinations of photon energies in the spectral range from 150 eV to 780 eV can be chosen. In this paper, simulations of the spectral transmission and performance parameters of the filter technique are discussed, along with a monochromator with dispersion compensation presently under construction.

MuscleX is an integrated, open-source computer software suite for data reduction of X-ray fiber diffraction patterns from striated muscle and other fibrous systems. It is written in Python and runs on Linux, Microsoft Windows or macOS. Most modules can be run either from a graphical user interface or in a `headless mode' from the command line, suitable for incorporation into beamline control systems. Here, we provide an overview of the general structure of the MuscleX software package and describe the specific features of the individual modules as well as examples of applications.

Errors in variable subscripts, equations and Fig. 8 in Section 3.2 of the article by Lotze et al. [(2024). J. Synchrotron Rad. 31, 42–52] are corrected.

The ability to freely control the polarization of X-rays enables measurement techniques relying on circular or linear dichroism, which have become indispensable tools for characterizing the properties of chiral molecules or magnetic structures. Therefore, the demand for polarization control in X-ray free-electron lasers is increasing to enable polarization-sensitive dynamical studies on ultrafast time scales. The soft X-ray branch Athos of SwissFEL was designed with the aim of providing freely adjustable and arbitrary polarization by building its undulator solely from modules of the novel Apple X type. In this paper, the magnetic model of the linear inclined and circular Apple X polarization schemes are studied. The polarization is characterized by measuring the angular electron emission distributions of helium for various polarizations using cold target recoil ion momentum spectroscopy. The generation of fully linear polarized light of arbitrary angle, as well as elliptical polarizations of varying degree, are demonstrated.

Addressing the demand for high stability of beamline instruments at the SHINE facility, a high stability mirror regulating mechanism has been developed for mirror adjustments. Active mass damping was adopted to attenuate pitch angle vibrations of mirrors caused by structural vibrations. An internal absolute velocity feedback was used to reduce the negative impact of spillover effects and to improve performance. The experiment was conducted on a prototype structure of a mirror regulating mechanism, and results showed that the vibration RMS of the pitch angle was effectively attenuated from 47 nrad to 27 nrad above 1 Hz.

Full-field transmission X-ray microscopy has been recently implemented at the hard X-ray ROCK–SOLEIL quick-EXAFS beamline, adding micrometre spatial resolution to the second time resolution characterizing the beamline. Benefiting from a beam size versatility due to the beamline focusing optics, full-field hyperspectral XANES imaging has been successfully used at the Fe K-edge for monitoring the pressure-induced spin transition of a 150 µm × 150 µm Fe(o-phen)2(NCS)2 single crystal and the charge of millimetre-sized LiFePO4 battery electrodes. Hyperspectral imaging over 2000 eV has been reported for the simultaneous monitoring of Fe and Cu speciation changes during activation of a FeCu bimetallic catalyst along a millimetre-sized catalyst bed. Strategies of data acquisition and post-data analysis using Jupyter notebooks and multivariate data analysis are presented, and the gain obtained using full-field hyperspectral quick-EXAFS imaging for studies of functional materials under process conditions in comparison with macroscopic information obtained by non-spatially resolved quick-EXAFS techniques is discussed.

One of the most challenging aspects of X-ray research is the delivery of liquid sample flows into the soft X-ray beam. Currently, cylindrical microjets are the most commonly used sample injection systems for soft X-ray liquid spectroscopy. However, they suffer from several drawbacks, such as complicated geometry due to their curved surface. In this study, we propose a novel 3D-printed nozzle design by introducing microscopic flat sheet jets that provide micrometre-thick liquid sheets with high stability, intending to make this technology more widely available to users. Our research is a collaboration between the EuXFEL and MAX IV research facilities. This collaboration aims to develop and refine a 3D-printed flat sheet nozzle design and a versatile jetting platform that is compatible with multiple endstations and measurement techniques. Our flat sheet jet platform improves the stability of the jet and increases its surface area, enabling more precise scanning and differential measurements in X-ray absorption, scattering, and imaging applications. Here, we demonstrate the performance of this new arrangement for a flat sheet jet setup with X-ray photoelectron spectroscopy, photoelectron angular distribution, and soft X-ray absorption spectroscopy experiments performed at the photoemission end­station of the FlexPES beamline at MAX IV Laboratory in Lund, Sweden.

Beamline BL08U1A is a soft X-ray spectromicroscopy beamline at Shanghai Synchrotron Radiation Facility (SSRF) that exhibits the capabilities of high spatial resolution (30 nm) and high energy resolving power (over 104). As a first-generation beamline of SSRF, owing to its continuous operation over the last ten years, an urgent upgrade of the equipment including the monochromator was deemed necessary. The upgrade work included the overall construction of the monochromator and replacement of the mirrors upstream and downstream of the monochromator. Based on its original skeleton, two elliptically cylinder mirrors were designed to focus the beam horizontally, which can increase the flux density by about three times on the exit slits. Meanwhile, the application of variable-line-space gratings in the monochromator demonstrates the dual functions of dispersing and focusing on the exit slits which can decrease abberations dramatically. After the upgrade of the main components of the beamline, the energy range is 180–2000 eV, the energy resolving power reaches 16333 @ 244 eV and 12730 @ 401 eV, and the photon flux measured in the experimental station is over 2.45 × 109 photons s−1 (E/ΔE = 6440 @ 244 eV).

Under DAPHNE4NFDI, the X-ray absorption spectroscopy (XAS) reference database, RefXAS, has been set up. For this purpose, we developed a method to enable users to submit a raw dataset, with its associated metadata, via a dedicated website for inclusion in the database. Implementation of the database includes an upload of metadata to the scientific catalogue and an upload of files via object storage, with automated query capabilities through a web server and visualization of the data and files. Based on the mode of measurements, quality criteria have been formulated for the automated check of any uploaded data. In the present work, the significant metadata fields for reusability, as well as reproducibility of results (FAIR data principles), are discussed. Quality criteria for the data uploaded to the database have been formulated and assessed. Moreover, the usability and interoperability of available XAS data/file formats have been explored. The first version of the RefXAS database prototype is presented, which features a human verification procedure, currently being tested with a new user interface designed specifically for curators; a user-friendly landing page; a full list of datasets; advanced search capabilities; a streamlined upload process; and, finally, a server-side automatic authentication and (meta-) data storage via MongoDB, PostgreSQL and (data-) files via relevant APIs.

A state-of-the-art multilayer deposition system with a 4200 mm-long linear substrate translator housed within an ultra-high vacuum chamber has been developed. This instrument is engineered to produce single and multilayer coatings, accommodating mirrors up to 2000 mm in length through the utilization of eight rectangular cathodes. To ensure the quality and reliability of the coatings, the system incorporates various diagnostic tools for in situ thickness uniformity and stress measurement. Furthermore, the system features an annealing process capable of heating up to 700°C within the load-lock chamber. The entire operation, including pump down, deposition and venting processes, is automated through user-friendly software. In addition, all essential log data, power of sputtering source, working pressure and motion positions are automatically stored for comprehensive data analysis. Preliminary commissioning results demonstrate excellent lateral film thickness uniformity, achieving 0.26% along the translation direction over 1500 mm in dynamic mode. The multilayer deposition system is poised for use in fabricating periodic, lateral-graded and depth-graded multilayers, specifically catering to the beamlines for diverse scientific applications at Diamond Light Source.

The Circular Electron–Positron Collider (CEPC) in China can also work as an excellent powerful synchrotron light source, which can generate high-quality synchrotron radiation. This synchrotron radiation has potential advantages in the medical field as it has a broad spectrum, with energies ranging from visible light to X-rays used in conventional radiotherapy, up to several megaelectronvolts. FLASH radiotherapy is one of the most advanced radiotherapy modalities. It is a radiotherapy method that uses ultra-high dose rate irradiation to achieve the treatment dose in an instant; the ultra-high dose rate used is generally greater than 40 Gy s−1, and this type of radiotherapy can protect normal tissues well. In this paper, the treatment effect of CEPC synchrotron radiation for FLASH radiotherapy was evaluated by simulation. First, a Geant4 simulation was used to build a synchrotron radiation radiotherapy beamline station, and then the dose rate that the CEPC can produce was calculated. A physicochemical model of radiotherapy response kinetics was then established, and a large number of radiotherapy experimental data were comprehensively used to fit and determine the functional relationship between the treatment effect, dose rate and dose. Finally, the macroscopic treatment effect of FLASH radiotherapy was predicted using CEPC synchrotron radiation through the dose rate and the above-mentioned functional relationship. The results show that the synchrotron radiation beam from the CEPC is one of the best beams for FLASH radiotherapy.

The development of hard X-ray nanoprobe techniques has given rise to a number of experimental methods, like nano-XAS, nano-XRD, nano-XRF, ptychography and tomography. Each method has its own unique data processing algorithms. With the increase in data acquisition rate, the large amount of generated data is now a big challenge to these algorithms. In this work, an intuitive, user-friendly software system is introduced to integrate and manage these algorithms; by taking advantage of the loosely coupled, component-based design approach of the system, the data processing speed of the imaging algorithm is enhanced through optimization of the parallelism efficiency. This study provides meaningful solutions to tackle complexity challenges faced in synchrotron data processing.

Xray free-electron lasers (XFELs) enable experiments that would have been impractical or impossible at conventional X-ray laser facilities. Indeed, more XFEL facilities are being built and planned, with their aim to deliver larger pulse energies and higher peak brilliance. While seeking to increase the pulse power, it is quintessential to consider the maximum pulse fluence that a grazing-incidence FEL mirror can withstand. To address this issue, several studies were conducted on grazing-incidence damage by soft X-ray FEL pulses at the European XFEL facility. Boron carbide (B4C) coatings on polished silicon substrate were investigated using 1 keV photon energy, similar to the X-ray mirrors currently installed at the soft X-ray beamlines (SASE3). The purpose of this study is to compare the damage threshold of B4C and Si to determine the advantages, tolerance and limits of using B4C coatings.

A second crystalline modification of the title compound, C12H19N3S [common name: cis-jasmone thio­semicarbazone] was crystallized from tetra­hydro­furane at room temperature. There is one crystallographic independent mol­ecule in the asymmetric unit, showing disorder in the cis-jasmone chain [site-occupancy ratio = 0.590 (14):0.410 (14)]. The thio­semicarbazone entity is approximately planar, with the maximum deviation from the mean plane through the N/N/C/S/N atoms being 0.0463 (14) Å [r.m.s.d. = 0.0324 Å], while for the five-membered ring of the jasmone fragment, the maximum deviation from the mean plane through the carbon atoms amounts to 0.0465 (15) Å [r.m.s.d. = 0.0338 Å]. The mol­ecule is not planar due to the dihedral angle between these two fragments, which is 8.93 (1)°, and due to the sp3-hybridized carbon atoms in the jasmone fragment chain. In the crystal, the mol­ecules are connected by N—H⋯S and C—H⋯S inter­actions, with graph-set motifs R22(8) and R21(7), building mono-periodic hydrogen-bonded ribbons along [010]. A Hirshfeld surface analysis indicates that the major contributions for the crystal cohesion are H⋯H (67.8%), H⋯S/S⋯H (15.0%), H⋯C/C⋯H (8.5%) and H⋯N/N⋯H (5.6%) [only non-disordered atoms and those with the highest s.o.f. were considered]. This work reports the second crystalline modification of the cis-jasmone thio­semicarbazone structure, the first one being published recently [Orsoni et al. (2020). Int. J. Mol. Sci. 21, 8681–8697] with the crystals obtained in ethanol at 273 K.

Three B2-type inter­metallic AlFe1 – δ phases (0.18 < δ < 0.05) in the Al–Fe binary system were synthesized by smelting and high temperature sinter­ing methods. The exact crystal structure for δ = 0.05 was refined by single-crystal X-ray diffraction. The amount of vacancy defects at the Fe atom sites was obtained by refining the corresponding site occupancy factor, converging to the chemical formula AlFe0.95, with a structure identical to that of ideal AlFe models inferred from powder X-ray or neutron diffraction patterns.

The manganese title complex, [Mn(C7H5N2O4)2(C7H6N2O4)2(H2O)2]·2H2O, is one of the first 4-amino 3-nitro­benzoic acid (4 A3NBA) monoligand metal complexes to be synthesized. It crystallizes in the centrosymmetric monoclinic space group P21/n with the complex mol­ecules located on inversion centers. Four 4 A3NBA ligand mol­ecules are monodentately coordinated by the Mn2+ ion through the carb­oxy­lic oxygen atoms while the other two positions of the inner coordination sphere are occupied by water mol­ecules, giving rise to a distorted octa­hedron, and two water mol­ecules are in the outer coordination sphere. There are two intra­molecular hydrogen bonds in the complex mol­ecule. The first is of the common N—H⋯O=N type, while the second is a rarely occurring very strong hydrogen bond in which a common proton is shared by two uncoordinated oxygen atoms of neighboring carboxyl­ate groups. In the crystal, an intricate system of inter­molecular hydrogen bonds links the complex mol­ecules into a three-dimensional-network.

Single crystals of the inter­metallic phase with composition Ti4Ni2C were serendipitously obtained by high-pressure sinter­ing of a mixture with initial chemical composition Ti2Ni. The Ti4Ni2C phase crystallizes in the Fdoverline{3}m space group and can be considered as a partially filled Ti2Ni structure with the C atom occupying an octa­hedral void. Ti4Ni2C is isotypic with Ti4Ni2O, Nb4Ni2C and Ta4Ni2C, all of which were studied previously by means of powder diffraction.

Neodymium(III) ortho-oxidotungstate(VI) was synthesized as a side-product in an unsuccessful synthesis attempt at fluoride derivatives of neodymium tungstate in fused silica ampoules, using neodymium(III) oxide, neodymium(III) fluoride and tungsten trioxide. Violet, platelet-shaped single crystals of the title compound emerged of the bulk, which crystallize in the defect scheelite type with a trigonal dodeca­hedral coordination of oxide anions around the Nd3+ cations and the hexa­valent tungsten cations situated in the centers of oxide tetra­hedra.

The extraction and purification procedures, crystallization and crystal structure refinement (single-crystal X-ray data) of germacrone type II, C15H22O, are presented. The structural results are compared with a previous powder X-ray synchrotron study [Kaduk et al. (2022). Powder Diffr. 37, 98–104], revealing significant improvements in terms of accuracy and precision. Hirshfeld atom refinement (HAR), as well as Hirshfeld surface analysis, give insight into the inter­molecular inter­actions of germacrone type II.

In the title compound, C14H14O3, the dihedral angle between the aromatic rings is 39.76 (9)°. In the crystal, the mol­ecules associate to form centrosymmetric acid–acid dimers linked by pairwise O—H⋯O hydrogen bonds. The precision of the geometric parameters in the present single-crystal study is about an order of magnitude better than the previous powder diffraction study [Chattopadhyay et al. (2013). CrystEngComm, 15, 1077–1085].

In the title compound, C21H27BF2N2O4, a highly fluorescent boron–dipyrromethene dye, the methyl­propionate moieties have different conformations. In the crystal, weak C—H⋯F and C—H⋯O inter­actions link the mol­ecules. Some optical properties are presented.

α-d-2'-De­oxy­ribonucleosides are products of the γ-irradiation of DNA under oxygen-free conditions and are constituents of anomeric DNA. They are not found as natural building blocks of canonical DNA. Reports on their conformational properties are limited. Herein, the single-crystal X-ray structure of α-d-2'-de­oxy­adenosine (α-dA), C10H13N5O3, and its conformational parameters were determined. In the crystalline state, α-dA forms two conformers in the asymmetric unit which are connected by hydro­gen bonds. The sugar moiety of each conformer is arranged in a `clamp'-like fashion with respect to the other conformer, forming hydro­gen bonds to its nucleobase and sugar residue. For both conformers, a syn conformation of the nucleobase with respect to the sugar moiety was found. This is contrary to the anti conformation usually preferred by α-nucleosides. The sugar conformation of both conformers is C2'-endo, and the 5'-hydroxyl groups are in a +sc orientation, probably due to the hydro­gen bonds formed by the conformers. The formation of the supra­molecular assembly of α-dA is controlled by hydro­gen bonding and stacking inter­actions, which was verified by a Hirshfeld and curvedness surface analysis. Chains of hydro­gen-bonded nucleobases extend parallel to the b direction and are linked to equivalent chains by hydro­gen bonds involving the sugar moieties to form a sheet. A com­parison of the solid-state structures of the anomeric 2'-de­oxy­adenosines revealed significant differences of their conformational parameters.

A confiscated package of street drugs was characterized by the usual mass spectral (MS) and FT–IR analyses. The confiscated powder material was highly crystalline and was found to consist of two very different species, accidentally of sizes convenient for X-ray diffraction. Thus, one each was selected and redundant com­plete sets of data were collected at 100 K using Cu Kα radiation. The selected crystals contained: (a) 1,2-diphenyl-2-(pyrrolidin-1-yl)ethanone hy­dro­chloride hemihydrate or 1-(2-oxo-1,2-di­phenyl­eth­yl)pyrrolidin-1-ium chloride hemihydrate, C18H20NO+·Cl−·0.5H2O, (I), a synthetic cathinone called `α-D2PV', and (b) the sugar myo-inositol, C6H12O6, (II), probably the only instance in which the drug and its diluent have been fully characterized from a single confiscated sample. Moreover, the structural details of both are rather attractive showing: (i) inter­esting hydrogen bonding observed in pairwise inter­actions by the drug mol­ecules, mediated by the chloride counter-anions and the waters of crystallization, and (ii) π–π inter­actions in the case of the phenyl rings of the drug which are of two different types, namely, π–π stacking and edge-to-π. Finally, the inositol crystallizes with Z' = 2 and the resulting diastereoisomers were examined by overlay techniques.

The crystal structure of a new 1:1 cocrystal of carbamazepine and S-naproxen (C15H12N2O·C14H14O3) was solved from powder X-ray diffraction (PXRD). The PXRD pattern was measured at the high-resolution beamline CRISTAL at synchrotron SOLEIL (France). The structure was solved using Monte Carlo simulated annealing, then refined with Rietveld refinement. The positions of the H atoms were obtained from density functional theory (DFT) ground-state calculations. The symmetry is ortho­rhom­bic with the space group P212121 (No. 19) and the following lattice parameters: a = 33.5486 (9), b = 26.4223 (6), c = 5.3651 (10) Å and V = 4755.83 (19) Å3.

The structures of five ammonium salt forms of mono­sulfonated azo dyes, derivatives of 4-(2-phenyldiazen-1-yl)benzenesulfonate, with the general formula [NH4][O3S(C6H4)NN(C6H3)RR']·XH2O [R = OH, NH2 or N(C2H4OH)2; R' = H or OH] are presented. All form simple layered structures with alternating hydro­phobic (organic) and hydro­philic (cation, solvent and polar groups) layers. To assess for isostructural behaviour of the ammonium cation with M+ ions, the packing of these structures is compared with literature examples. To aid this comparison, the corresponding structures of four potassium salt forms of the mono­sulfonated azo dyes are also presented herein. Of the five ammonium salts it is found that three have isostructural equivalents. In two cases this equivalent is a potassium salt form and in one case it is a rubidium salt form. The isostructurality of ion packing and of unit-cell symmetry and dimensions tolerates cases where the ammonium ions form somewhat different inter­action types with coformer species than do the potassium or rubidium ions. No sodium salt forms are found to be isostructural with any ammonium equivalent. However, similarities in the anion packing within a single hydro­phobic layer are found for a group that consists of the ammonium and rubidium salt forms of one azo anion species and the sodium and silver salt forms of a different azo species.

Beauveriolides, including the main beauveriolide I {systematic name: (3R,6S,9S,13S)-9-benzyl-13-[(2S)-hexan-2-yl]-6-methyl-3-(2-methyl­prop­yl)-1-oxa-4,7,10-tri­aza­cyclo­tridecane-2,5,8,11-tetrone, C27H41N3O5}, are a series of cyclo­depsipeptides that have shown promising results in the treatment of Alzheimer's disease and in the prevention of foam cell formation in atherosclerosis. Their crystal structure studies have been difficult due to their tiny crystal size and fibre-like morphology, until now. Recent developments in 3D electron diffraction methodology have made it possible to accurately study the crystal structures of submicron crystals by overcoming the problems of beam sensitivity and dynamical scattering. In this study, the absolute structure of beauveriolide I was determined by 3D electron diffraction. The cyclo­dep­si­peptide crystallizes in the space group I2 with lattice parameters a = 40.2744 (4), b = 5.0976 (5), c = 27.698 (4) Å and β = 105.729 (6)°. After dynamical refinement, its absolute structure was determined by comparing the R factors and calculating the z-scores of the two possible enanti­omorphs of beauveriolide I.

This report presents a comprehensive investigation into the synthesis and characterization of Schiff base com­pounds derived from benzene­sul­fon­amide. The synthesis process, involved the reaction between N-cyclo­amino-2-sulf­anil­amide and various substituted o-salicyl­aldehydes, resulted in a set of com­pounds that were subjected to rigorous characterization using advanced spectral techniques, including 1H NMR, 13C NMR and FT–IR spectroscopy, and single-crystal X-ray diffraction. Furthermore, an in-depth assessment of the synthesized com­pounds was conducted through Absorption, Distribution, Metabolism, Excretion and Toxicity (ADMET) analysis, in conjunction with docking studies, to elucidate their pharmacokinetic profiles and potential. Impressively, the ADMET analysis showcased encouraging drug-likeness properties of the newly synthesized Schiff bases. These computational findings were substanti­ated by mol­ecular properties derived from density functional theory (DFT) calculations using the B3LYP/6-31G* method within the Jaguar Module of Schrödinger 2023-2 from Maestro (Schrodinger LLC, New York, USA). The ex­plor­ation of frontier mol­ecular orbitals (HOMO and LUMO) enabled the computation of global reactivity descriptors (GRDs), encompassing charge separation (Egap) and global softness (S). Notably, within this analysis, one Schiff base, namely, 4-bromo-2-{N-[2-(pyr­rol­idine-1-sul­fonyl)phenyl]car­box­imid­oyl}phenol, 20, em­erged with the smallest charge separation (ΔEgap = 3.5780 eV), signifying heightened potential for biological properties. Conversely, 4-bromo-2-{N-[2-(piper­idine-1-sul­fonyl)phenyl]car­box­imid­oyl}phenol, 17, exhibited the largest charge separation (ΔEgap = 4.9242 eV), implying a relatively lower propensity for biological activity. Moreover, the synthesized Schiff bases displayed re­marke­able inhibition of tankyrase poly(ADP-ribose) polymerase enzymes, integral in colon cancer, surpassing the efficacy of a standard drug used for the same purpose. Additionally, their bioavailability scores aligned closely with established medications such as trifluridine and 5-fluoro­uracil. The ex­plor­ation of mol­ecular electrostatic potential through colour mapping delved into the electronic behaviour and reactivity tendencies intrinsic to this diverse range of mol­ecules.

X-ray and electron diffraction methods independently identify the S-enanti­omer of Berkecoumarin [systematic name: (S)-8-hy­droxy-3-(2-hy­droxy­prop­yl)-6-meth­oxy-2H-chromen-2-one]. Isolated from Berkeley Pit Lake Penicillium sp., Berkecoumarin is a natural product with a light-atom com­position (C13H14O5) that challenges in-house absolute structure determination by anomalous scattering. This study further demonstrates the utility of dynamical refinement of electron-diffraction data for absolute structure determination.

The coordination of hydro­tris­[3-(2-furyl)pyrazol-1-yl]borate (Tp2-Fu, C21H16BN6O3) to lan­tha­nide(III) ions is achieved for the first time with the com­plex [Ln(Tp2-Fu)2](BPh4)·xCH2Cl2 (1-Ln has Ln = Ce and x = 2; 1-Dy has Ln = Dy and x = 1). This was accom­plished via both hydrous (Ln = Ce) and anhydrous methods (Ln = Dy). When isolating the dysprosium analogue, the filtrate produced a second crop of crystals which were revealed to be the 1,2-borotropic-shifted product [Dy(κ4-Tp2-Fu)(κ5-Tp2-Fu*)](BPh4) (2) {Tp2-Fu* = hydro­bis­[3-(2-furyl)pyrazol-1-yl][5-(2-furyl)pyrazol-1-yl]borate}. We con­clude that the pres­ence of a strong Lewis acid and a sterically crowded coordination environment are contributing factors for the 1,2-borotropic shifting of scorpionate ligands in conjunction with the size of the conical angle with the scorpionate ligand.

The influence of the crystal synthesis method on the crystallographic structure of caffeine–citric acid co­crystals was analyzed thanks to the synthesis of a new polymorphic form of the cocrystal. In order to com­pare the new form to the already known forms, the crystal structure of the new cocrystal (C8H10N4O2·C6H8O7) was solved by powder X-ray diffraction thanks to synchrotron experiments. The structure determination was performed using `GALLOP', a recently developed hybrid approach based on a local optimization with a particle swarm optimizer, particularly powerful when applied to the structure resolution of materials of pharmaceutical inter­est, com­pared to classical Monte-Carlo simulated annealing. The final structure was obtained through Rietveld refinement, and first-principles density functional theory (DFT) calculations were used to locate the H atoms. The symmetry is triclinic with the space group Poverline{1} and contains one mol­ecule of caffeine and one mol­ecule of citric acid per asymmetric unit. The crystallographic structure of this cocrystal involves different hydrogen-bond associations com­pared to the already known structures. The analysis of these hydrogen bonds indicates that the cocrystal obtained here is less stable than the co­crystals already identified in the literature. This analysis is confirmed by the determination of the melting point of this cocrystal, which is lower than that of the previously known co­crystals.

The crystal structures of three mixed-valence copper cyanide alkanolamine polymers are presented, together with thermogravimetric analysis (TGA) and electron spin resonance (ESR) data. In all three structures, a CuII moiety on a crystallographic center of symmetry is coordinated by two alkanolamines and links two CuICN chains via cyanide bridging groups to form diperiodic sheets. The sheets are linked together by cuprophilic CuI–CuI inter­actions to form a three-dimensional network. In poly[bis­(μ-3-amino­propano­lato)tetra-μ-cyan­ido-dicopper(I)dicopper(II)], [Cu4(CN)4(C3H8NO)2]n, 1, propano­lamine bases have lost their hydroxyl H atoms and coordinate as chelates to two CuII atoms to form a dimeric CuII moiety bridged by the O atoms of the bases with CuII atoms in square-planar coordination. The ESR spectrum is very broad, indicating exchange between the two CuII centers. In poly[bis­(2-amino­pro­pan­ol)tetra-μ-cyanido-dicopper(I)copper(II)], [Cu3(CN)4(C3H9NO)2]n, 2, and poly[bis­(2-amino­ethanol)tetra-μ-cyanido-dicopper(I)copper(II)], [Cu3(CN)4(CH7NO)2]n, 3, a single CuII atom links the CuICN chains together via CN bridges. The chelating alkanolamines are not ionized, and the OH groups form rather long bonds in the axial positions of the octa­hedrally coordinated CuII atoms. The coordination geometries of CuII in 2 and 3 are almost identical, except that the Cu—O distances are longer in 2 than in 3, which may explain their somewhat different ESR spectra. Thermal decom­position in 2 and 3, but not in 1, begins with the loss of HCN(g), and this can be correlated with the presence of OH protons on the ligands in 2 and 3, which are not present in 1.

The receptor ability of diethyl N,N'-(1,3-phenyl­ene)dicarbamate (1) to form host–guest com­plexes with theophylline (TEO) and caffeine (CAF) by mechanochemistry was evaluated. The formation of the 1–TEO com­plex (C12H16N2O4·C7H8N4O2) was preferred and involves the conformational change of one of the ethyl carbamate groups of 1 from the endo conformation to the exo conformation to allow the formation of inter­molecular inter­actions. The formation of an N—H⋯O=C hydrogen bond between 1 and TEO triggers the conformational change of 1. CAF mol­ecules are unable to form an N—H⋯O=C hydrogen bond with 1, making the conformational change and, therefore, the formation of the com­plex impossible. Conformational change and selective binding were monitored by IR spectroscopy, solid-state 13C nuclear magnetic resonance and single-crystal X-ray diffraction. The 1–TEO com­plex was characterized by IR spectroscopy, solid-state 13C nuclear magnetic resonance, powder X-ray diffraction and single-crystal X-ray diffraction.

We stand fully behind our earlier suggestion [Raymond & Girolami (2023). Acta Cryst. C79, 445–455] that the claim by Fish and co-workers [Chen et al. (1995). J. Am. Chem. Soc. 117, 9097–9098; Smith et al. (2014). Organometallics, 33, 2389–2404] of a linear two-coordinate rhodium(I) species is incorrect, and that the putative rhodium atom is in fact silver.

By studying the structures of (μ-1,4,10,13-tetra­thia-7,16-di­aza­cyclo­octa­deca­ne)bis[iodidopalladium(II)] diiodide penta­(diiodine), [Pd2I2(C12H26N2S4)](I)2·5I2 or [Pd2I2([18]aneN2S4)](I)2·(I2)5, and 4,7,13,16,21,24-hexa­oxa-1,10-diazo­niabi­cyclo­[8.8.8]hexa­cosane triiodide iodide hemi­penta­(diiodine) di­chloro­methane mono­solvate, C18H38N2O62+·I3−·I−·2.5I2·CH2Cl2 or [H2([2.2.2]cryptand)](I3)(I)(I2)2.5·CH2Cl2, we confirm the structural variety of extended polyiodides achievable upon changing the shape, charge and dimensions of the cation template, by altering the synthetic strategy adopted and/or the experimental conditions. Although it is still often difficult to characterize discrete [I2m+n]n− polyiodides higher than I3− on the basis of structural parameters, such as I—I bond distances, FT–Raman spectroscopy appears to identify them as aggregates of I2, I− and (symmetric or slightly asymmetric) I3− building blocks linked by I⋯I inter­actions of varying strengths. However, because FT–Raman spectroscopy carries no information about the topological features of extended polyiodides, the two techniques should therefore be applied in combination to enhance the analysis of this kind of compounds.

The synthesis and structural characterization of three families of coordination com­plexes synthesized from 4'-phenyl-2,2':6',2''-terpyridine (8, Ph-TPY), 4'-(4-chloro­phen­yl)-2,2':6',2''-terpyridine (9, ClPh-TPY) and 4'-(4-meth­oxy­phen­yl)-2,2':6',2''-terpyridine (10, MeOPh-TPY) ligands with the divalent metals Co2+, Fe2+, Mn2+ and Ni2+ are reported. The com­pounds were synthesized from a 1:2 mixture of the metal and ligand, resulting in a series of com­plexes with the general formula [M(R-TPY)2](ClO4)2 (where M = Co2+, Fe2+, Mn2+ and Ni2+, and R-TPY = Ph-TPY, ClPh-TPY and MeOPh-TPY). The general formula and structural and supra­molecular features were determinated by single-crystal X-ray diffraction for bis­(4'-phenyl-2,2':6',2''-terpyridine)­nickel(II) bis­(per­chlo­rate), [Ni(C21H15N3)2](ClO4)2 or [Ni(Ph-TPY)2](ClO4)2, bis­[4'-(4-meth­oxy­phen­yl)-2,2':6',2''-terpyridine]­manganese(II) bis­(per­chlo­rate), [Mn(C22H17N3O)2](ClO4)2 or [Mn(MeOPh-TPY)2](ClO4)2, and bis­(4'-phenyl-2,2':6',2''-ter­py­ridine)­manganese(II) bis­(per­chlo­rate), [Mn(C21H15N3)2](ClO4)2 or [Mn(Ph-TPY)2](ClO4)2. In all three cases, the com­plexes present distorted octa­hedral coordination polyhedra and the crystal packing is determined mainly by weak C—H⋯π inter­actions. All the com­pounds (except for the Ni derivatives, for which FT–IR, UV–Vis and thermal analysis are reported) were fully characterized by spectroscopic (FT–IR, UV–Vis and NMR spectroscopy) and thermal (TGA–DSC, thermogravimetric analysis–differential scanning calorimetry) methods.

Using a 1:1 cocrystal of (E)-N-(3,4-di­fluoro­phen­yl)-1-(pyridin-4-yl)methanimine with acetic acid, C12H8F2N2·C2H4O2, we investigate the influence of F atoms introduced to the aromatic ring on promoting π–π inter­actions. The cocrystal crystallizes in the triclinic space group P1. Through crystallographic analysis and com­putational studies, we reveal the mol­ecular arrangement within this co­crystal, demonstrating the presence of hydrogen bonding between the acetic acid mol­ecule and the pyridyl group, along with π–π inter­actions between the aromatic rings. Our findings highlight the importance of F atoms in promoting π–π inter­actions without necessitating full halogenation of the aromatic ring.

Geminal and vicinal bis­(tri­fluoro­methane­sulfonate) esters are highly reactive alkyl­ene synthons used as potent electrophiles in the macrocyclization of imid­azoles and the transformation of bypyridines to diquat derivatives via nucleophilic substitution reactions. Herein we report the crystal structures of methyl­ene (C3H2F6O6S2) and ethyl­ene bis­(tri­fluoro­methane­sulfonate) (C4H4F6O6S2), the first examples of a geminal and vicinal bis­(tri­fluoro­methane­sulfonate) ester characterized by single-crystal X-ray diffraction (SC-XRD). With melting points slightly below ambient temperature, both reported bis­(tri­fluoro­methane­sulfonate)s are air- and moisture-sensitive oils and were crys­tallized at 277 K to afford two-com­ponent non-merohedrally twinned crystals. The dominant inter­actions present in both com­pounds are non-classical C—H⋯O hydrogen bonds and inter­molecular C—F⋯F—C inter­actions between tri­fluoro­methyl groups. Mol­ecular electrostatic potential (MEP) cal­culations by DFT-D3 helped to qu­antify the polarity between O⋯H and F⋯F contacts to rationalize the self-sorting of both bis­(tri­fluoro­methane­sulfonate) esters in polar (non-fluorous) and non-polar (fluorous) domains within the crystal structure.

The salt ammonium 2-am­ino­mal­on­ate (systematic name: ammonium 2-aza­niumyl­propane­dioate), NH4+·C3H4NO4−, was synthesized in diethyl ether from the starting materials malonic acid, ammonia and bromine. The salt was recrystallized from water as colourless blocks. In the solid state, intra­molecular medium–strong N—H⋯O, weak C—H⋯O and weak C—H⋯N hydrogen bonds build a three-dimensional network.

The synthesis, crystal structure and magnetic properties of an ox­am­ate-con­taining erbium(III) com­plex, namely, tetra­butyl­ammonium aqua­[N-(2,4,6-tri­methyl­phen­yl)oxamato]erbium(III)–di­methyl sulfoxide–water (1/3/1.5), (C16H36N)[Er(C11H12NO3)4(H2O)]·3C2H6OS·1.5H2O or n-Bu4N[Er(Htmpa)4(H2O)]·3DMSO·1.5H2O (1), are reported. The crystal structure of 1 reveals the occurrence of an erbium(III) ion, which is surrounded by four N-phenyl-substituted ox­am­ate ligands and one water mol­ecule in a nine-coordinated environment, together with one tetra­butyl­ammonium cation acting as a counter-ion, and one water and three dimethyl sulfoxide (DMSO) mol­ecules of crystallization. Variable-temperature static (dc) and dynamic (ac) magnetic mea­sure­ments were carried out for this mononuclear com­plex, revealing that it behaves as a field-induced single-ion magnet (SIM) below 5.0 K.

Starting from [Mn(C5H4Br)(PPh3)(CO)2] (1a), the cymantrenyl thio­ethers [Mn(C5H4SMe)(PPh3)(CO)2] (1b) and [Mn{C5H4–nBr(SMe)n}(PPh3)(CO)2] (n = 1 for com­pound 2, n = 2 for 3 and n = 3 for 4) were obtained, using either n-butyllithium (n-BuLi), lithium diiso­propyl­amide (LDA) or lithium tetra­methyl­piperidide (LiTMP) as base, followed by electrophilic quenching with MeSSMe. Stepwise consecutive reaction of [Mn(C5Br5)(PPh3)(CO)2] with n-BuLi and MeSSMe led finally to [Mn{C5(SMe)5}(PPh3)(CO)2] (11), only the fifth com­plex to be reported containing a perthiol­ated cyclo­penta­dienyl ring. The mol­ecular and crystal structures of 1b, 3, 4 and 11 were determined and were studied for the occurrence of S⋯S and S⋯Br inter­actions. It turned out that although some inter­actions of this type occurred, they were of minor importance for the arrangement of the mol­ecules in the crystal.

The highly cytotoxic macrocyclic trichothecene Isororidin A (C29H40O9) was isolated from the fungus Myrothesium verrucaria endophytic on the wild medicinal plant `Datura' (Datura stramonium L.) and was characterized by one- (1D) and two-dimensional (2D) NMR spectroscopy. The three-dimensional structure of Isororidin A has been confirmed by X-ray crystallography at 0.81 Å resolution from crystals grown in the ortho­rhom­bic space group P212121, with one mol­ecule per asymmetric unit. Isororidin A is the epimer of previously described (by X-ray crystallography) Roridin A at position C-13' of the macrocyclic ring.

The title compound, 3-[(benzo-1,3-dioxol-5-yl)amino]-4-meth­oxy­cyclo­but-3-ene-1,2-dione, C12H9NO5 (3), is a precursor to an anti­mycobacterial squaramide. Block-shaped crystals of a monoclinic form (3-I, space group P21/c, Z = 8, Z' = 2) and needle-shaped crystals of a triclinic form (3-II, space group P-1, Z = 4, Z' = 2) were found to crystallize concomitantly. In both crystal forms, R22(10) dimers assemble through N—H⋯O=C hydrogen bonds. These dimers are formed from crystallographically unique mol­ecules in 3-I, but exhibit crystallographic Ci symmetry in 3-II. Twinning by pseudomerohedry was encountered in the crystals of 3-II. The conformations of 3 in the solid forms 3-I and 3-II are different from one another but are similar for the unique mol­ecules in each polymorph. Density functional theory (DFT) calculations on the free mol­ecule of 3 indicate that a nearly planar conformation is preferred.

Chalcopyrite, the world's primary copper ore mineral, is abundant in Latin America. Copper extraction offers significant economic and social benefits due to its strategic importance across various industries. However, the hydro­metallurgical route, considered more environmentally friendly for processing low-grade chal­co­py­rite ores, remains challenging, as does its concentration by froth flotation. This limited understanding stems from the poorly understood structure and reactivity of chal­co­py­rite surfaces. This study reviews recent contributions using density functional theory (DFT) calculations with periodic boundary conditions and slab models to elucidate chal­co­py­rite surface properties. Our analysis reveals that reconstructed surfaces preferentially expose S atoms at the topmost layer. Furthermore, some studies report the formation of di­sulfide groups (S22−) on pristine sulfur-terminated surfaces, accom­panied by the reduction of Fe3+ to Fe2+, likely due to surface oxidation. Additionally, Fe sites are consistently identified as favourable adsorption locations for both oxygen (O2) and water (H2O) mol­ecules. Finally, the potential of com­puter modelling for investigating collector–chal­co­py­rite surface inter­actions in the context of selective froth flotation is discussed, highlighting the need for further research in this area.

The reaction of titanium(IV) chloride with sodium hexa­fluoro­iso­pro­pox­ide, carried out in hexa­fluoro­iso­propanol, produces titanium(IV) hexa­fluoro­iso­pro­pox­ide, which is a liquid at room temperature. Recrystallization from coordinating solvents, such as aceto­nitrile or tetra­hydro­furan, results in the formation of bis-solvate com­plexes. These com­pounds are of inter­est as possible Ziegler–Natta polymerization catalysts. The aceto­nitrile com­plex had been structurally characterized previously and adopts a distorted octahedral structure in which the nitrile ligands adopt a cis configuration, with nitro­gen lone pairs coordinated to the metal. The low-melting tetra­hydro­furan com­plex has not provided crystals suitable for single-crystal X-ray analysis. However, the structure of chlorido­tris­(hexa­fluoro­isopropoxido-κO)bis­(tetra­hydro­furan-κO)titanium(IV), [Ti(C3HF6O)3Cl(C4H8O)2], has been obtained and adopts a distorted octa­hedral coordination geometry, with a facial arrangement of the alkoxide ligands and adjacent tetra­hydro­furan ligands, coordinated by way of metal–oxygen polar coordinate inter­actions.

A series of organotin heterocycles of general formula [{Me2C(C6H3CH2)2O}SnR2] [R = methyl (Me, 4), n-butyl (n-Bu, 5), benzyl (Bn, 6) and phenyl (Ph, 7)] was easily synthesized by a Barbier-type reaction assisted by the sonochemical activation of metallic magnesium. The 119Sn{1H} NMR data for all four com­pounds confirm the presence of a central Sn atom in a four-coordinated environment in solution. Single-crystal X-ray diffraction studies for 17,17-dimethyl-7,7-di­phenyl-15-oxa-7-stanna­tetra­cyclo­[11.3.1.05,16.09,14]hepta­deca-1,3,5(16),9(14),10,12-hexa­­ene, [Sn(C6H5)2(C17H16O)], 7, at 100 and 295 K con­firmed the formation of a mono­nuclear eight-membered heterocycle, with a conformation depicted as boat–chair, resulting in a weak Sn⋯O inter­action. The Sn and O atoms are surrounded by hydro­phobic C—H bonds. A Hirshfeld surface analysis of 7 showed that the eight-membered heterocycles are linked by weak C—H⋯π, π–π and H⋯H noncovalent inter­actions. The pairwise inter­action energies showed that the cohesion between the heterocycles are mainly due to dispersion forces.