Single-crystal growth, differential thermal analysis (DTA), derivative thermogravimetry (DTG), differential scanning calorimetry (DSC), X-ray structural studies and polarized microscopy observations of bis(ethylenediammonium) tetrabromozincate(II) bromide [NH3(CH2)2NH3]2[ZnBr4]Br2 are presented. A reversible phase transition is described. At room temperature, the complex crystallizes in the monoclinic system. In some cases, the single crystals are twinned into two or more large domains of ferroelastic type with domain walls in the (100) crystallographic plane. DTA and DTG measurements show chemical stability of the crystal up to ∼538 K. In the DSC studies, a reversible isostructural phase transition was revealed at ∼526/522 K on heating/cooling run, respectively. Optical observation on the heating run reveals that at the phase transition the plane of twinning (domain wall) does not disappear and additionally the appearance of a new domain structure of ferroelastic type with domain walls in the planes (101), (101), (100) and (001) is observed. The domain structure pattern is preserved after cooling to the room-temperature phase and the symmetry of this phase is unchanged.

Monoclinic ferroelectric phases are prevalent in various functional materials, most notably mixed-ion perovskite oxides. These phases can manifest as regularly ordered long-range crystallographic structures or as macroscopic averages of the self-assembled tetragonal/rhombohedral nanodomains. The structural and physical properties of monoclinic ferroelectric phases play a pivotal role when exploring the interplay between ferroelectricity, ferroelasticity, giant piezoelectricity and multiferroicity in crystals, ceramics and epitaxial thin films. However, the complex nature of this subject presents challenges, particularly in deciphering the microstructures of monoclinic domains. In Paper I [Biran & Gorfman (2024). Acta Cryst. A80, 112–128] the geometrical principles governing the connection of domain microstructures formed by pairing MAB type monoclinic domains were elucidated. Specifically, a catalog was established of `permissible domain walls', where `permissible', as originally introduced by Fousek & Janovec [J. Appl. Phys. (1969), 40, 135–142], denotes a mismatch-free connection between two monoclinic domains along the corresponding domain wall. The present article continues the prior work by elaborating on the formalisms of permissible domain walls to describe domain microstructures formed by pairing the MC type monoclinic domains. Similarly to Paper I, 84 permissible domain walls are presented for MC type domains. Each permissible domain wall is characterized by Miller indices, the transformation matrix between the crystallographic basis vectors of the domains and, crucially, the expected separation of Bragg peaks diffracted from the matched pair of domains. All these parameters are provided in an analytical form for easy and intuitive interpretation of the results. Additionally, 2D illustrations are provided for selected instances of permissible domain walls. The findings can prove valuable for various domain-related calculations, investigations involving X-ray diffraction for domain analysis and the description of domain-related physical properties.

Protein tyrosine phosphatase 1B (PTP1B) plays important roles in cellular homeostasis and is a highly validated therapeutic target for multiple human ailments, including diabetes, obesity and breast cancer. However, much remains to be learned about how conformational changes may convey information through the structure of PTP1B to enable allosteric regulation by ligands or functional responses to mutations. High-resolution X-ray crystallography can offer unique windows into protein conformational ensembles, but comparison of even high-resolution structures is often complicated by differences between data sets, including non-isomorphism. Here, the highest resolution crystal structure of apo wild-type (WT) PTP1B to date is presented out of a total of ∼350 PTP1B structures in the PDB. This structure is in a crystal form that is rare for PTP1B, with two unique copies of the protein that exhibit distinct patterns of conformational heterogeneity, allowing a controlled comparison of local disorder across the two chains within the same asymmetric unit. The conformational differences between these chains are interrogated in the apo structure and between several recently reported high-resolution ligand-bound structures. Electron-density maps in a high-resolution structure of a recently reported activating double mutant are also examined, and unmodeled alternate conformations in the mutant structure are discovered that coincide with regions of enhanced conformational heterogeneity in the new WT structure. These results validate the notion that these mutations operate by enhancing local dynamics, and suggest a latent susceptibility to such changes in the WT enzyme. Together, these new data and analysis provide a detailed view of the conformational ensemble of PTP1B and highlight the utility of high-resolution crystallography for elucidating conformational heterogeneity with potential relevance for function.

Mycobacterium tuberculosis can reside and persist in deep tissues; latent tuberculosis can evade immune detection and has a unique mechanism to convert it into active disease through reactivation. M. tuberculosis Rv1421 (MtRv1421) is a hypothetical protein that has been proposed to be involved in nucleotide binding-related metabolism in cell-growth and cell-division processes. However, due to a lack of structural information, the detailed function of MtRv1421 remains unclear. In this study, a truncated N-terminal domain (NTD) of MtRv1421, which contains a Walker A/B-like motif, was purified and crystallized using PEG 400 as a precipitant. The crystal of MtRv1421-NTD diffracted to a resolution of 1.7 Å and was considered to belong to either the C-centered monoclinic space group C2 or the I-centered orthorhombic space group I222, with unit-cell parameters a = 124.01, b = 58.55, c = 84.87 Å, β = 133.12° or a = 58.53, b = 84.86, c = 90.52 Å, respectively. The asymmetric units of the C2 or I222 crystals contained two or one monomers, respectively. In terms of the binding ability of MtRv1421-NTD to various ligands, uridine diphosphate (UDP) and UDP-N-acetylglucosamine significantly increased the melting temperature of MtRv1421-NTD, which indicates structural stabilization through the binding of these ligands. Altogether, the results reveal that a UDP moiety may be required for the interaction of MtRv1421-NTD as a nucleotide-binding protein with its ligand.

Pseudoalteromonas fuliginea sp. PS47 is a recently identified marine bacterium that has extensive enzymatic machinery to metabolize polysaccharides, including a locus that targets pectin-like substrates. This locus contains a gene (locus tag EU509_03255) that encodes a pectin-degrading lyase, called PfPL1, that belongs to polysaccharide lyase family 1 (PL1). The 2.2 Å resolution X-ray crystal structure of PfPL1 reveals the compact parallel β-helix fold of the PL1 family. The back side of the core parallel β-helix opposite to the active site is a meandering set of five α-helices joined by lengthy loops. A comparison of the active site with those of other PL1 enzymes suggests a catalytic mechanism that is independent of metal ions, such as Ca2+, but that substrate recognition may require metal ions. Overall, this work provides the first structural insight into a pectinase of marine origin and the first structure of a PL1 enzyme in subfamily 2.

Porphyromonas gingivalis is a major pathogenic oral bacterium that is responsible for periodontal disease. It is linked to chronic periodontitis, gingivitis and aggressive periodontitis. P. gingivalis exerts its pathogenic effects through mechanisms such as immune evasion and tissue destruction, primarily by secreting various factors, including cysteine proteases such as gingipain K (Kgp), gingipain R (RgpA and RgpB) and PrtH (UniProtKB ID P46071). Virulence proteins comprise multiple domains, including the pro-peptide region, catalytic domain, K domain, R domain and DUF2436 domain. While there is a growing database of knowledge on virulence proteins and domains, there was no prior evidence or information regarding the structure and biological function of the well conserved DUF2436 domain. In this study, the DUF2436 domain of PrtH from P. gingivalis (PgDUF2436) was determined at 2.21 Å resolution, revealing a noncanonical β-jelly-roll sandwich topology with two antiparallel β-sheets and one short α-helix. Although the structure of PgDUF2436 was determined by the molecular-replacement method using an AlphaFold model structure as a template, there were significant differences in the positions of β1 between the AlphaFold model and the experimentally determined PgDUF2436 structure. The Basic Local Alignment Search Tool sequence-similarity search program showed no sequentially similar proteins in the Protein Data Bank. However, DaliLite search results using structure-based alignment revealed that the PgDUF2436 structure has structural similarity Z-scores of 5.9–5.4 with the C-terminal domain of AlgF, the D4 domain of cytolysin, IglE and the extracellular domain structure of PepT2. This study has elucidated the structure of the DUF2436 domain for the first time and a comparative analysis with similar structures has been performed.

Direct measurements have been taken of nanoscale domain structure in ferroelectric lead zirconate titanate around a grain boundary. Characterizing the evolution of this structure under an electric field is critical for predicting dielectric and piezoelectric response.

The crystal structure of Cd5(TeO3)4(NO3)2 exhibits a distinct layered arrangement, whereas Cd4Te5O14 crystallizes with a framework structure.

In the complex, the ligand binds to the metal through an oxygen atom. The geometry of the seven-coordinate U atom is penta­gonal bipyramidal, with the uranyl O atoms in apical positions.

In the title compound, the tellurium(VI) and vanadium(V) atoms are statistically disordered over two of the ten metal-atom sites in the unprotonated [TeV9O28]5– heteropolyanion.

Theoretical and experimental structural studies of the title compound were undertaken using X-ray and DFT methods. The inter­actions present in the crystal were analyzed using Hirshfeld surface and MEP surface analysis. Docking studies with a covid-19 main protease (PDB ID: 6LU7) as the target receptor indicate that the synthesized compound may be a potential candidate for pharmaceutical applications.

Crystallization of the title compound from CH2Cl2/n-pentane (1:5 v/v) at room temperature gave two polymorphs, which crystallize in monoclinic (P21/c; α form) and ortho­rhom­bic (Pna21; β form) space groups. The ReI complex mol­ecules in either polymorph adopt a six-coordinate octa­hedral geometry with three facially-oriented carbonyl ligands, one bromido ligand, and two nitro­gen atoms from one chelating ligand ppt-OMe. In the crystal, both polymorph α and β form di-periodic sheet-like architectures supported by multiple hydrogen bonds.

The title compound is a non-liquid crystal mol­ecule. The mol­ecular crystal is consolidated by C—Br⋯O&z-dbnd;C type contacts running continuously along the [001] direction.

The effect of an electric field on local domain structure near a 24° tilt grain boundary in a 200 nm-thick Pb(Zr0.2Ti0.8)O3 bi-crystal ferroelectric film was probed using synchrotron nanodiffraction. The bi-crystal film was grown epitaxially on SrRuO3-coated (001) SrTiO3 24° tilt bi-crystal substrates. From the nanodiffraction data, real-space maps of the ferroelectric domain structure around the grain boundary prior to and during application of a 200 kV cm−1 electric field were reconstructed. In the vicinity of the tilt grain boundary, the distributions of densities of c-type tetragonal domains with the c axis aligned with the film normal were calculated on the basis of diffracted intensity ratios of c- and a-type domains and reference powder diffraction data. Diffracted intensity was averaged along the grain boundary, and it was shown that the density of c-type tetragonal domains dropped to ∼50% of that of the bulk of the film over a range ±150 nm from the grain boundary. This work complements previous results acquired by band excitation piezoresponse force microscopy, suggesting that reduced nonlinear piezoelectric response around grain boundaries may be related to the change in domain structure, as well as to the possibility of increased pinning of domain wall motion. The implications of the results and analysis in terms of understanding the role of grain boundaries in affecting the nonlinear piezoelectric and dielectric responses of ferroelectric materials are discussed.

Crystallization of the title compound, fac-[ReBr(ppt-OMe)(CO)3] (ppt-OMe = C15H12N2OS), from CH2Cl2/n-pentane (1:5 v/v) at room temperature gave two polymorphs, which crystallize in monoclinic (P21/c; α form) and orthorhombic (Pna21; β form) space groups. The ReI complex molecules in either polymorph adopt a six-coordinate octahedral geometry with three facially-oriented carbonyl ligands, one bromido ligand, and two nitrogen atoms from one chelating ligand ppt-OMe. In the crystal, both polymorph α and β form di-periodic sheet-like architectures supported by multiple hydrogen bonds. In polymorph α, two types of hydrogen bonds (C—H...O) are found while, in polymorph β, four types of hydrogen bonds (C—H...O and C—H...Br) exist.

In the title compound, C8H9BrN2O2, the C—O—C—C torsion angle between isonicotine and the ethyl group is 180.0 (2)°. Intramolecular N—H...O and C—H...O interactions consolidate the molecular structure. In the crystal, N—H...N interaction form S(5) zigzag chains along [010]. The most significant contributions to the Hirshfeld surface arise from H...H (33.2%), Br...H/H...Br (20.9%), O...H/H...O (11.2%), C...H/H...C (11.1%) and N...H/H...N (10%) contacts. The topology of the three-dimensional energy frameworks was generated using the B3LYP/6–31 G(d,p) model to calculate the total interaction energy. The net interaction energies for the title compound are Eele = 59.2 kJ mol−1, Epol = 15.5 kJ mol−1, Edis = 140.3 kJ mol−1 and Erep = 107.2 kJ mol−1 with a total interaction energy Etot of 128.8 kJ mol−1. The molecular structure was optimized by density functional theory (DFT) at the B3LYP/6–311+G(d,p) level and the theoretical and experimentally obtained parameters were compared. The frontier molecular orbitals HOMO and LUMO were generated, giving an energy gap ΔE of 4.0931 eV. The MEP was generated to identify active sites in the molecule and molecular docking studies carried out with the title compound (ligand) and the covid-19 main protease PDB ID: 6LU7, revealing a moderate binding affinity of −5.4 kcal mol−1.

A plug-flow fixed-bed cell for synchrotron powder X-ray diffraction (PXRD) and X-ray absorption fine structure (XAFS) idoneous for the study of heterogeneous catalysts at high temperature, pressure and under gas flow is designed, constructed and demonstrated. The operating conditions up to 1000°C and 50 bar are ensured by a set of mass flow controllers, pressure regulators and two infra-red lamps that constitute a robust and ultra-fast heating and cooling method. The performance of the system and cell for carbon dioxide hydrogenation reactions under specified temperatures, gas flows and pressures is demonstrated both for PXRD and XAFS at the P02.1 (PXRD) and the P64 (XAFS) beamlines of the Deutsches Elektronen-Synchrotron (DESY).

In recent years, China's advanced light sources have entered a period of rapid construction and development. As modern X-ray detectors and data acquisition technologies advance, these facilities are expected to generate massive volumes of data annually, presenting significant challenges in data management and utilization. These challenges encompass data storage, metadata handling, data transfer and user data access. In response, the Data Organization Management Access Software (DOMAS) has been designed as a framework to address these issues. DOMAS encapsulates four fundamental modules of data management software, including metadata catalogue, metadata acquisition, data transfer and data service. For light source facilities, building a data management system only requires parameter configuration and minimal code development within DOMAS. This paper firstly discusses the development of advanced light sources in China and the associated demands and challenges in data management, prompting a reconsideration of data management software framework design. It then outlines the architecture of the framework, detailing its components and functions. Lastly, it highlights the application progress and effectiveness of DOMAS when deployed for the High Energy Photon Source (HEPS) and Beijing Synchrotron Radiation Facility (BSRF).

In this work, Ce-doped yttria-stabilized zirconia (YSZ) and pure YSZ phases were subjected to irradiation with 14 MeV Au ions. Irradiation studies were performed to simulate long-term structural and microstructural damage due to self-irradiation in YSZ phases hosting alpha-active radioactive species. It was found that both the Ce-doped YSZ and the YSZ phases had a reasonable tolerance to irradiation at high ion fluences and the bulk crystallinity was well preserved. Nevertheless, local microstrain increased in all compounds under study after irradiation, with the Ce-doped phases being less affected than pure YSZ. Doping with cerium ions increased the microstructural stability of YSZ phases through a possible reduction in the mobility of oxygen atoms, which limits the formation of structural defects. Doping of YSZ with tetravalent actinide elements is expected to have a similar effect. Thus, YSZ phases are promising for the safe long-term storage of radioactive elements. Using synchrotron radiation diffraction, measurements of the thin irradiated layers of the Ce-YSZ and YSZ samples were performed in grazing incidence (GI) mode. A corresponding module for measurements in GI mode was developed at the Rossendorf Beamline and relevant technical details for sample alignment and data collection are also presented.

At-wavelength metrology of X-ray optics plays a crucial role in evaluating the performance of optics under actual beamline operating conditions, enabling in situ diagnostics and optimization. Techniques utilizing a wavefront random modulator have gained increasing attention in recent years. However, accurately mapping the measured wavefront slope to a curved X-ray mirror surface when the modulator is downstream of the mirror has posed a challenge. To address this problem, an iterative method has been developed in this study. The results demonstrate a significant improvement compared with conventional approaches and agree with offline measurements obtained from optical metrology. We believe that the proposed method enhances the accuracy of at-wavelength metrology techniques, and empowers them to play a greater role in beamline operation and optics fabrication.

With the development of synchrotron radiation sources and high-frame-rate detectors, the amount of experimental data collected at synchrotron radiation beamlines has increased exponentially. As a result, data processing for synchrotron radiation experiments has entered the era of big data. It is becoming increasingly important for beamlines to have the capability to process large-scale data in parallel to keep up with the rapid growth of data. Currently, there is no set of data processing solutions based on the big data technology framework for beamlines. Apache Hadoop is a widely used distributed system architecture for solving the problem of massive data storage and computation. This paper presents a set of distributed data processing schemes for beamlines with experimental data using Hadoop. The Hadoop Distributed File System is utilized as the distributed file storage system, and Hadoop YARN serves as the resource scheduler for the distributed computing cluster. A distributed data processing pipeline that can carry out massively parallel computation is designed and developed using Hadoop Spark. The entire data processing platform adopts a distributed microservice architecture, which makes the system easy to expand, reduces module coupling and improves reliability.

Knife-edge imaging is a successful method for determining the wavefront distortion of focusing optics such as Kirkpatrick–Baez mirrors or compound refractive lenses. In this study, the wavefront error of an imperfect elliptical mirror is predicted by developing a knife-edge program using the SHADOW/OASYS platform. It is shown that the focusing optics can be aligned perfectly by minimizing the parabolic and cubic coefficients of the wavefront error. The residual wavefront error provides precise information about the figure/height errors of the focusing optics suggesting it as an accurate method for in situ optical metrology. A Python program is developed to design a customized wavefront refractive corrector to minimize the residual wavefront error. Uniform beam at and out of focus and higher peak intensity are achieved by the wavefront correction in comparison with ideal focusing. The developed code provides a quick way for wavefront error analysis and corrector design for non-ideal optics especially for the new-generation diffraction-limited sources, and saves considerable experimental time and effort.

High energy resolution fluorescence detected X-ray absorption spectroscopy is a powerful method for probing the electronic structure of functional materials. The X-ray penetration depth and photon-in/photon-out nature of the method allow operando experiments to be performed, in particular in electrochemical cells. Here, operando high-resolution X-ray absorption measurements of a BiVO4 photoanode are reported, simultaneously probing the local electronic states of both cations. Small but significant variations of the spectral lineshapes induced by the applied potential were observed and an explanation in terms of the occupation of electronic states at or near the band edges is proposed.

Nanoscale structural and electronic heterogeneities are prevalent in condensed matter physics. Investigating these heterogeneities in 3D has become an important task for understanding material properties. To provide a tool to unravel the connection between nanoscale heterogeneity and macroscopic emergent properties in magnetic materials, scanning transmission X-ray microscopy (STXM) is combined with X-ray magnetic circular dichroism. A vector tomography algorithm has been developed to reconstruct the full 3D magnetic vector field without any prior noise assumptions or knowledge about the sample. Two tomographic scans around the vertical axis are acquired on single-crystalline Nd2Fe14B pillars tilted at two different angles, with 2D STXM projections recorded using a focused 120 nm X-ray beam with left and right circular polarization. Image alignment and iterative registration have been implemented based on the 2D STXM projections for the two tilts. Dichroic projections obtained from difference images are used for the tomographic reconstruction to obtain the 3D magnetization distribution at the nanoscale.

Imaging energy filters in photoelectron microscopes and momentum microscopes use spherical fields with deflection angles of 90°, 180° and even 2 × 180°. These instruments are optimized for high energy resolution, and exhibit image aberrations when operated in high transmission mode at medium energy resolution. Here, a new approach is presented for bandpass-filtered imaging in real or reciprocal space using an electrostatic dodecapole with an asymmetric electrode array. In addition to energy-dispersive beam deflection, this multipole allows aberration correction up to the third order. Here, its use is described as a bandpass prefilter in a time-of-flight momentum microscope at the hard X-ray beamline P22 of PETRA III. The entire instrument is housed in a straight vacuum tube because the deflection angle is only 4° and the beam displacement in the filter is only ∼8 mm. The multipole is framed by transfer lenses in the entrance and exit branches. Two sets of 16 different-sized entrance and exit apertures on piezomotor-driven mounts allow selection of the desired bandpass. For pass energies between 100 and 1400 eV and slit widths between 0.5 and 4 mm, the transmitted kinetic energy intervals are between 10 eV and a few hundred electronvolts (full width at half-maximum). The filter eliminates all higher or lower energy signals outside the selected bandpass, significantly improving the signal-to-background ratio in the time-of-flight analyzer.

Transition-metal nitro­gen-doped carbons (TM-N-C) are emerging as a highly promising catalyst class for several important electrocatalytic processes, including the electrocatalytic CO2 reduction reaction (CO2RR). The unique local environment around the singly dispersed metal site in TM-N-C catalysts is likely to be responsible for their catalytic properties, which differ significantly from those of bulk or nanostructured catalysts. However, the identification of the actual working structure of the main active units in TM-N-C remains a challenging task due to the fluctional, dynamic nature of these catalysts, and scarcity of experimental techniques that could probe the structure of these materials under realistic working conditions. This issue is addressed in this work and the local atomistic and electronic structure of the metal site in a Co–N–C catalyst for CO2RR is investigated by employing time-resolved operando X-ray absorption spectroscopy (XAS) combined with advanced data analysis techniques. This multi-step approach, based on principal component analysis, spectral decomposition and supervised machine learning methods, allows the contributions of several co-existing species in the working Co–N–C catalysts to be decoupled, and their XAS spectra deciphered, paving the way for understanding the CO2RR mechanisms in the Co–N–C catalysts, and further optimization of this class of electrocatalytic systems.

The differentially pumped rare-gas filter at the end of the VUV beamline of the Swiss Light Source has been adapted to house a windowless absorption cell for gases. Absorption spectra can be recorded from 7 eV to up to 21 eV photon energies routinely, as shown by a new water and nitrous oxide absorption spectrum. By and large, the spectra agree with previously published ones both in terms of resonance energies and absorption cross sections, but that of N2O exhibits a small shift in the { ilde{f D}} band and tentative fine structures that have not yet been fully described. This setup will facilitate the measurement of absorption spectra in the VUV above the absorption edge of LiF and MgF2 windows. It will also allow us to carry out condensed-phase measurements on thin liquid sheets and solid films. Further development options are discussed, including the recording of temperature-dependent absorption spectra, a stationary gas cell for calibration measurements, and the improvement of the photon energy resolution.

Achieving diffraction-limited performance in fourth-generation synchrotron radiation sources demands monochromator crystals that can preserve the wavefront across an unprecedented extensive range. There is an urgent need for techniques of absolute crystal diffraction wavefront measurement. At the Beijing Synchrotron Radiation Facility (BSRF), a novel edge scan wavefront metrology technique has been developed. This technique employs a double-edge tracking method, making diffraction-limited level absolute crystal diffraction wavefront measurement a reality. The results demonstrate an equivalent diffraction surface slope error below 70 nrad (corresponding to a wavefront phase error of 4.57% λ) r.m.s. within a nearly 6 mm range for a flat crystal in the crystal surface coordinate. The double-edge structure contributes to exceptional measurement precision for slope error reproducibility, achieving levels below 15 nrad (phase error reproducibility < λ/100) even at a first-generation synchrotron radiation source. Currently, the measurement termed double-edge scan (DES) has already been regarded as a critical feedback mechanism in the fabrication of next-generation crystals.

The title compound, [RuCl2(C25H22P2)2] or [RuCl2(dppm)2] (dppm = bis­(di­phenyl­phosphan­yl)methane, C25H22P2) crystallizes as two half-mol­ecules (completed by inversion symmetry) in space group Poverline{1} (Z = 2), with the RuII atoms occupying inversion centers at 0,0,0 and 1/2, 1/2, 1/2, respectively. The bidentate phosphane ligands occupy equatorial positions while the chlorido ligands complete the distorted octa­hedral coordination spheres at axial positions. The bite angles of the phosphane chelates are similar for the two mol­ecules [(P—Ru—P)avg. = 71.1°], while there are significant differences in the twisting of the methyl­ene backbone, with a distance of the methyl­ene C atom from the RuP4 plane of 0.659 (2) and 0.299 (3) Å, respectively, and also for the phenyl substituents for both mol­ecules due to variations in weak C—H⋯Cl inter­actions.

The structure of the title solvated porphyrin, C56H38N8O2·C6H14, is reported. Two porphyrin mol­ecules, one ordered and one disordered n-hexane solvate mol­ecules are present in its asymmetric unit. The porphyrin macrocycle shows a characteristic saddle-shaped distortion, and the maximum deviation from the mean plane for non-hydrogen atoms is 0.48 Å. N—H⋯N, N—H⋯O, and C—H⋯O hydrogen bonds, as well as π–π inter­actions, are observed in the crystal structure.

The title complex, [PdCl2(C9H13N)2], comprises a single mol­ecule in the asymmetric unit. The PdII atom is tetra­coordinated by two N atoms from two trans-aligned organic ligands and two Cl ligands, forming a square-planar metal coordination environment. The distances from the ortho-H atoms on the phenyl ring to the central PdII atom fall within the range 4.70–5.30 Å, precluding any significant intra­molecular Pd⋯H inter­actions.

In the title complex, [ZnCl2(C14H12N2O2)], the ZnII atom is located on a twofold rotation axis and is fourfold coordinated by two chlorido ligands and a bidentate 4,7-meth­oxy-1,10-phenanthroline ligand in a distorted tetra­hedral environment. Weak π–π stacking inter­actions between adjacent 4,7-dimeth­oxy-1,10-phenanthroline rings [centroid-to-centroid distances = 3.5969 (11) and 3.7738 (11) Å] contribute to the alignment of the complexes in layers parallel to (overline{2}01).

A new square-planar palladium complex salt hydrate, (C9H12NO)2[PdCl4]·0.5H2O, has been characterized. The asymmetric unit of the complex salt comprises two [PdCl4]2− dianions, four 2-hy­droxy-2,3-di­hydro-1H-inden-1-aminium cations, each derived from (1R,2S)-(+)-1-amino­indan-2-ol, and one water mol­ecule of crystallization. In the crystal, a two-dimensional layer parallel to (001) features a number of O—H⋯O, N—H⋯O, O—H⋯Cl and N—H⋯Cl hydrogen bonds.

In the title triazole-based N-heterocyclic carbene rhodium(I) cationic complex with a tetra­fluorido­borate counter-anion, [Rh(C8H12)(C8H15N3)(C18H15P)]BF4, which crystallizes with two cations and two anions in the asymmetric unit, the Rh center has a distorted square-planar coordination geometry with expected bond distances. Several nonclassical C—H⋯F hydrogen-bonding inter­actions help to consolidate the packing. Two of the F atoms of one of the anions are disordered over adjacent sites in a 0.814 (4):0.186 (4) ratio.

The title pyrene-fused spiro­pyran derivative, C30H25NO, crystallizes with two mol­ecules in the asymmetric unit with dihedral angles between their fused-ring sub units of 76.20 (8) and 89.38 (9)°. In the crystal, weak C—H⋯π inter­actions link the mol­ecules into a three-dimensional network.

The structure of the title compound, [RuCl2(C7H10N2)2(C2H6OS)2], has monoclinic (P21/n) symmetry. The Ru—N distances of the coordination compound are influenced by the trans chloride or di­methyl­sulfoxide-κS ligands. The mol­ecular structure exhibits disorder for two of the terminal methyl groups of a dimethyl sulfoxide ligand.

The title SiIV complex, C16H21NO3Si, is built up by a tridentate dinegative Schiff base ligand bound to a sila­cyclo­hexane unit. The coordination geometry of the penta­coordinated SiIV atom is a distorted trigonal bipyramid. The presence of the sila­cyclo­hexane ring in the complex leads to an unusual coordination geometry of the SiIV atom with the N atom from the Schiff base ligand and an alkyl-C atom in apical positions of the trigonal bipyramid. There is a disorder of the methyl group at the imine bond with two orientations resolved for the H atoms [major orientation = 0.55 (3)]. In the crystal, C—H⋯O inter­actions are found within corrugated layers of mol­ecules parallel to the ab plane.

The title compound, trans-di­bromido­tetra­kis­(5-methyl-1H-pyrazole-κN2)manganese(II), [MnBr2(C4H6N2)4] or [Mn(3-MePzH)4Br2] (1) crystallizes in the triclinic Poverline{1} space group with the cell parameters a = 7.6288 (3), b = 8.7530 (4), c = 9.3794 (4) Å and α = 90.707 (4), β = 106.138 (4), γ = 114.285 (5)°, V = 542.62 (5) Å3, T = 120 K. The asymmetric unit contains only half the mol­ecule with the manganese atom is situated on a crystallographic inversion center. The 3-MePzH ligands are present in an AABB type manner with two methyl groups pointing up and the other two down. The supra­molecular architecture is characterized by several inter­molecular C—H⋯N, N—H⋯Br, and C—H⋯π inter­actions. Earlier, a polymorphic structure of [Mn(3-MePzH)4Br2] (2) with a similar geometry and also an AABB arrangement for the pyrazole ligands was described [Reedijk et al. (1971). Inorg. Chem. 10, 2594–2599; a = 8.802 (6), b = 9.695 (5), c = 7.613 (8) Å and α = 105.12 (4), β = 114.98 (4), γ = 92.90 (3)°, V = 558.826 (5) Å3, T = 295 K]. A varying supra­molecular pattern was reported, with the structure of 1 featuring a herringbone type pattern while that of structure 2 shows a pillared network type of arrangement along the a axis. A nickel complex [Ni(3-MePzH)4Br2] isomorphic to 1 and the analogous chloro derivatives of FeII, CoII and CuII are also known.

The title compound, C16H12FN3OS, a fluorinated di­thio­carbazate imine derivative, was synthesized by the one-pot, multi-component condensation reaction of hydrazine hydrate, carbon di­sulfide, 4-fluoro­benzyl chloride and isatin. The compound demonstrates near-planarity across much of the mol­ecule in the solid state and a Z configuration for the azomethine C=N bond. The Z form is further stabilized by the presence of an intra­molecular N—H⋯O hydrogen bond. In the extended structure, mol­ecules are linked into dimers by N—H⋯O hydrogen bonds and further connected into chains along either [2overline{1}0] or [100] by weak C—H⋯S and C—H⋯F hydrogen bonds, which further link into corrugated sheets and in combination form the overall three-dimensional network.

The title compound, [Ru(C19H13N5)2](PF6)2·3C4H10O, was obtained from the reaction of Ru(bimpy)Cl3 [bimpy is 2,6-bis­(1H-benzimidazol-2-yl)pyridine] and bimpy in refluxing ethanol followed by recrystallization from diethyl ether/aceto­nitrile. At 125 K the complex has ortho­rhom­bic (Pca21) symmetry. It is remarkable that the structure is almost centrosymmetric. However, refinement in space group Pbcn leads to disorder and definitely worse results. It is of inter­est with respect to potential catalytic reduction of CO2. The structure displays N—H⋯O, N—H⋯F hydrogen bonding and significant π–π stacking and C—H⋯π stacking inter­actions.

The title compound, [Ag(C15H9N3S2)2]ClO4·2CH3OH, is monoclinic. The AgI atom is coordinated by pyrido N atoms and is two-coordinate; however, the AgI atom has nearby O atoms that can be assumed to be weakly bonded – one from the perchlorate anion and one from the methanol solvate molecule. One of the thienyl groups on a 2,3-bis­(thio­phen-2-yl)pyrido[3,4-b]pyrazine is flipped disordered and was refined to occupancies of 68.4 (6) and 31.6 (6)%.

The mol­ecule of the title NCNHCS pincer N-heterocyclic carbene palladium(II) complex, [PdBr(C21H25N3S)]Br, exhibits a slightly distorted square-planar coordination at the palladium(II) atom, with the five-membered chelate ring nearly planar. The six-membered chelate ring adopts an envelope conformation. Upon chelation, the sulfur atom becomes a stereogenic centre with an RS configuration induced by the chiral carbon of the precursor imidazolium salt. There are intra­molecular C—H⋯Br—Pd hydrogen bonds in the structure. The two inter­stitial Br atoms, as the counter-anion of the structure, are both located on crystallographic twofold axes and are connected to the complex cations via C—H⋯·Br hydrogen bonds.

The use of acetic acid (HOAc) in a reaction between CuCl2·2H2O and secnid­azole, an active pharmaceutical ingredient useful in the treatment against a variety of anaerobic Gram-positive and Gram-negative bacteria, affords the title complex, [CuCl2(C7H11N3O3)2]. This compound was previously synthesized using ethanol as solvent, although its crystal structure was not reported [Betanzos-Lara et al. (2013). Inorg. Chim. Acta, 397, 94–100]. In the mol­ecular complex, the Cu2+ cation is situated at an inversion centre and displays a square-planar coordination environment. There is a hydrogen-bonded framework based on inter­molecular O—H⋯Cl inter­actions, characterized by H⋯Cl separations of 2.28 (4) Å and O—H⋯Cl angles of 175 (3)°. The resulting supra­molecular network is based on R22(18) ring motifs, forming chains in the [010] direction.

The structure of the title compound, C8H7IO3, at 90 K has monoclinic (P21/c) symmetry. The extended structure is layered and displays inter­molecular and intra­molecular hydrogen bonding arising from the same OH group.

In the structure of the title complex, [Zn(C4H2FN2O2)(C10H24N4)]ClO4, the zinc(II) ion forms coordination bonds with the four nitro­gen atoms of cyclam (1,4,8,11-tetra­aza­cyclo­tetra­decane or [14]aneN4) as well as with the nitro­gen atom of a deprotonated 5-fluoro­uracil ion (FU−). Cyclam adopts a trans-I type conformation within this structure. The coordination structure of the zinc(II) ion is a square pyramid with a distorted base plane formed by the four nitro­gen atoms of the cyclam. FU− engages in inter­molecular hydrogen bonding with neighboring FU− mol­ecules and with the cyclam mol­ecule.

The title complex, [Cu(C8H18NO5)Cl] or [Cu(H4bis-tris­)Cl], was obtained starting from the previously reported [Cu(H5bis-tris­)Cl]Cl compound. The deprotonation of the amino­polyol ligand H5bis-tris {[bis­(2-hy­droxy­eth­yl)amino]­tris­(hy­droxy­meth­yl)methane, C8H19NO5} promotes the formation of a very strong O—H⋯O inter­molecular hydrogen bond, characterized by an H⋯O separation of 1.553 (19) Å and an O—H⋯O angle of 178 (4)°. The remaining hy­droxy groups are also engaged in hydrogen bonds, forming R22(8), R44(16), R44(20) and R44(22) ring motifs, which stabilize the triperiodic supra­molecular network.

Transamination of Sn(NMe2)4 with H2NMes (Mes is 2,4,6-tri­methyl­phenyl, C9H11) led to the formation of the title compound, [Sn(C9H12N)4] or Sn(NHMes)4, which crystallizes in the tetra­gonal space group Poverline{4}21c, with four formula units per unit cell. The mol­ecular structure consists of a central tin(IV) atom, which is surrounded by four NHMes groups. Sn(NHMes)4 possesses crystallographically imposed overline{4} symmetry. The SnN4 coordination polyhedron is best described as a compressed bis­phenoid.

The title compound, [Fe(C84H52N12O4)Cl], crystallizes in space group C2/c. The central FeIII cation (site symmetry 2) is coordinated in a fivefold manner, with four pyrrole N atoms of the porphyrin core in the basal sites and one Cl atom (site symmetry 2) in the apical position, which completes a slightly distorted square-pyramidal environment. The porphyrin macrocycle shows a characteristic ruffled-shape distortion and the iron atom is displaced out of the porphyrin plane by 0.42 Å with the average Fe—N distance being 2.054 (4) Å; the Fe—Cl bond length is 2.2042 (7) Å. Inter­molecular C—H⋯N and C—H⋯O hydrogen bonds occur in the crystal structure.

The title compound, [Ir(C8H12)(C8H15N3)(C18H15P)]BF4, a new triazole-based N-heterocyclic carbene iridium(I) cationic complex with a tetra­fluorido­borate counter-anion, crystallizes with two cations and two anions in the asymmetric unit of space group Pc. The Ir centers of the cations have distorted square-planar conformations, formed by a bidentate (η2 + η2) cyclo­octa-1,5-diene (COD) ligand, an N-heterocyclic carbene and a tri­phenyl­phosphane ligand with the NHC carbon atom and P atom being cis. In the extended structure, non-classical C–H⋯F hydrogen bonds, one of which is notably short (H⋯F = 2.21 Å), link the cations and anions. The carbon atoms of one of the COD ligands are disordered over adjacent sites in a 0.62:0.38 ratio.

The PdII complex bis­{(S)-(−)-N-[(biphenyl-2-yl)methyl­idene]1-(4-meth­oxy­phen­yl)ethanamine-κN}di­chlorido­palladium(II), [PdCl2(C22H21NO)2], crystallizes in the monoclinic Sohncke space group P21 with a single mol­ecule in the asymmetric unit. The coordination environment around the palladium is slightly distorted square planar. The N—Pd—Cl bond angles are 91.85 (19), 88.10 (17), 89.96 (18), and 90.0 (2)°, while the Pd—Cl and Pd—N bond lengths are 2.310 (2) and 2.315 (2) Å and 2.015 (2) and 2.022 (6) Å, respectively. The crystal structure features inter­molecular N—H⋯Cl and intramolecular C—H⋯Pd inter­actions, which lead to the formation of a supramolecular framework structure.