The mol­ecular structure of C18H28O4, (+)-diplodiatoxin, is described, whereby the absolute configuration of the structure of diplodiatoxin has been confirmed by single-crystal X-ray diffraction. Diplodiatoxin crystallizes in the chiral P43212 space group with one mol­ecule in the asymmetric unit.

The title compound, [Ru(C12H14NO2)2(C12H8N2)]PF6 crystallizes in the tetra­gonal Sohnke space group P41212. The two bidentate chiral salicyloxazoline ligands and the phenanthroline co-ligand coordinate to the central RuIII atom through N,O and N,N atom pairs to form bite angles of 89.76 (15) and 79.0 (2)°, respectively. The octa­hedral coordination of the bidentate ligands leads to a propeller-like shape, which induces metal-centered chirality onto the complex, with a right-handed (Δ) absolute configuration [the Flack parameter value is −0.003 (14)]. Both the complex cation and the disordered PF6− counter-anion are located on twofold rotation axes. Apart from Coulombic forces, the crystal cohesion is ensured by non-classical C—H⋯O and C—H⋯F inter­actions.

The title compound, [Zn2(C6H8O4)2(C10H9N3)2]·3H2O or {Zn2[(C5H4N)2NH]2[μ-(CH2)4(COO)2]2}·3H2O, was separ­ated from the solvothermal reaction of zinc(II) sulfate hepta­hydrate, 2,2'-di­pyridyl­amine and sodium adipate. The dinuclear metal complex has a centrosymmetric structure, with the ZnII atom adopting a highly distorted octa­hedral coordination sphere composed of four oxygen atoms from bridging adipato ligands and two pyridine nitro­gen atoms. In the crystal, the title compound aggregates into a tri-periodic supra­molecular structure through inter­molecular hydrogen-bonding networks of the form O—H⋯O and N—H⋯O.

In the title compound, C6H10N2O2, the piperazine-2,3-dione ring adopts a half-chair conformation. In the crystal, the mol­ecules are linked by weak C—H⋯O hydrogen bonds, forming (010) sheets.

A new triazole-based N-heterocyclic carbene IrI cationic complex with a tetra­fluorido­borate counter-anion and hemi-solvating di­chloro­methane, [Ir(C8H12)(C8H15N3)(C18H15P)]BF4·0.5CH2Cl2, has been synthesized and structurally characterized. There are two independent ion pairs in the asymmetric unit and one di­chloro­methane solvent mol­ecule per two ion pairs. The cationic complex exhibits a distorted square-planar conformation around the IrI atom, formed by a bidentate cyclo­octa-1,5,diene (COD) ligand, a tri­phenyl­phosphane ligand, and an N-heterocyclic carbene (NHC). There are several close non-standard H⋯F hydrogen-bonding inter­actions that orient the tetra­fluorido­borate anions with respect to the IrI complex mol­ecules. The complex shows promising catalytic activity in transfer hydrogenation reactions. The structure was refined as a non-merohedral twin, and one of the COD mol­ecules is statistically disordered.

The title compound, C19H15BrN2O, crystallizes with two similar mol­ecules in the asymmetric unit. The extended structure features dimers linked by pairs of N—H⋯O and C—H⋯O hydrogen bonds. The HNCNO moiety of the title compound shows delocalization over the N—C—N part, as evidenced by the similar C—N bond distances.

The title di­thio­carbazate imine, C11H11N3OS2, was obtained from the condensation reaction of S-methyl­dithio­carbazate (SMDTC) and 5-methyl­isatin. It shows a Z configuration about the imine C=N bond, which is associated with an intra­molecular N—H⋯O hydrogen bond that closes an S(6) ring. In the crystal, inversion dimers linked by pairwise N—H⋯O hydrogen bonds generate R22(8) loops. The extended structure features C—H⋯S contacts as well as reciprocal carbon­yl–carbonyl (C=O⋯C=O) inter­actions.

The mol­ecular structure of the title compound, C20H26N2O2 reveals non-co-planarity between the central formamidine backbone and each of the outer meth­oxy- and i-propyl- substituted benzene rings with dihedral angles of 7.88 (15) and 81.17 (15)°, respectively, indicating significant twists in the mol­ecule. In the crystal, inter­molecular C—H⋯O inter­actions, forming an R34(30) graph set, occur within a two-dimensional layer that extends along the ac plane.

In the title solvate, C16H18N2O2·CH4O, the dihedral angles between the formamidine backbone and the pendant 2-meth­oxy­phenyl and 2,6-di­methyl­phenyl groups are 14.84 (11) and 81.61 (12)°, respectively. In the crystal, the components are linked by C—H⋯O, O—H⋯O and C—H⋯ π hydrogen bonds, generating a supra­molecular chain that extends along the crystallographic a-axis direction.

In the crystal of the title compound, C12H17N3, the mol­ecules are linked by N—H⋯N hydrogen bonds, generating a C(4) chain extending along the c-axis direction. One of the ethyl groups is disordered over two sets of sites with a refined occupancy ratio of 0.582 (15):0.418 (15).

The title compound, C8H8ClNO2, is significantly distorted from planarity, with a twist angle between the planes through the hy­droxy­benzene and acetamide groups being 23.5 (2)°. This conformation is supported by intra­molecular C—H⋯O and N—H⋯Cl contacts. In the crystal, N—H⋯O hydrogen-bonding contacts between acetamide groups and O—H⋯O contacts between hydroxyl groups form tapes propagating parallel to [103].

The crystal structure of a glycosyl­ated porphyrin (P_Gal2) system, C70H70N4O12, where two iso­propyl­idene protected galactose moieties are attached to the meso position of a substituted tetra­aryl porphyrin is reported. This structure reveals that the parent porphyrin is planar, with the galactose moieties positioned above and below the porphyrin macrocycle. This orientation likely prevents porphyrin–porphyrin H-type aggregation, potentially enhancing its efficiency as a photosensitizer in photodynamic therapy. Notable non-bonding C—H⋯O and C—H⋯π inter­actions among adjacent P_Gal2 systems are observed in this crystal network. Additionally, the tolyl groups of each porphyrin can engage in π–π inter­actions with the delocalized π-systems of neighboring porphyrins.

The title compound, C14H20NO5+·Cl−, was prepared as a racemate of R,R- and S,S-enanti­omers by reduction of the corresponding hy­droxy­imino­ketone. In the crystal, layers are formed via hydrogen bridges of four ammonium groups to chloride ions; these lamellae are connected via inter­digitated benzoic ester groups.

The title compound, C14H12O3, is an α-hy­droxy­carb­oxy­lic acid whose ortho­rhom­bic polymorph has been reported earlier [Qiu et al. (2007). Inorg. Chim. Acta, 360, 1819–1824]. The asymmetric unit contains two complete mol­ecules. Classical hydrogen bonds, as well as C—H⋯O contacts, connect the mol­ecules to infinite chains along the crystallographic c-axis direction.

The crystal structure of the title compound, C14H12N2O2S, reveals two symmetrically independent mol­ecules within the asymmetric unit. Each mol­ecule contains a chromenone core attached to a 2-thio­phene ring, cyano, and amino groups. The 2-thio­phene ring of one of the two mol­ecules in the asymmetric unit was found to be disordered over two positions, with the major component having a site occupancy factor of 0.837 (2). The 2-thio­phene ring is nearly orthogonal to the fused 4H-pyran ring, with dihedral angles between the two sets of planes being 89.5 (5) and 89.63 (8)°. Inter­molecular hydrogen bonding, involving N—H⋯N and N—H⋯O inter­actions, creates two distinct motifs leading to the formation of a two-dimensional supra­molecular network along the crystallographic ac plane.

The crystal structure of 1,4-bis­(neopent­yloxy)pillar[5]arene, C95H140N2O10 (TbuP), featuring two encapsulated pyridine mol­ecules, reveals significant host–guest inter­actions. Inter­estingly, the pyridine guests are positioned near the neopent­yloxy substituents instead of the electron-rich aromatic core of the pillar[5]arene. This spatial arrangement suggests a preference for the pyridine mol­ecules to engage with the aliphatic regions of the host. Detailed analysis of the structural characteristics of this host–guest system (TbuP·2Py), as well as its packing pattern within the crystal network, is presented and discussed.

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 report on the latest advancements in Microcrystal Electron Diffraction (3D ED/MicroED), as discussed during a symposium at the National Center for CryoEM Access and Training housed at the New York Structural Biology Center. This snapshot describes cutting-edge developments in various facets of the field and identifies potential avenues for continued progress. Key sections discuss instrumentation access, research applications for small mol­ecules and biomacromolecules, data collection hardware and software, data reduction software, and finally reporting and validation. 3D ED/MicroED is still early in its wide adoption by the structural science community with ample opportunities for expansion, growth, and innovation.

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.

The well-known copper car­box­yl­ate dimer, with four car­box­yl­ate ligands ex­ten­ding outwards towards the corners of a square, has been employed to generate a series of crystalline com­pounds. In particular, this work centres on the use of the 4-hy­droxy­benzoate anion (Hhba−) and its deprotonated phe­nol­ate form 4-oxidobenzoate (hba2−) to obtain complexes with the general formula [Cu2(Hhba)4–x(hba)xL2–y]x−, where L is an axial coligand (including solvent mol­ecules), x = 0, 1 or 2, and y = 0 or 1. In some cases, short hy­dro­gen bonds result in complexes which may be represented as [Cu2(Hhba)2(H0.5hba)2L2]−. The main focus of the investigation is on the formation of a variety of extended networks through hy­dro­gen bonding and, in some crystals, coordinate bonds when bridging coligands (L) are employed. Crystals of [Cu2(Hhba)4(di­ox­ane)2]·4(di­ox­ane) consist of the expected Cu dimer with the Hhba− anions forming hy­dro­gen bonds to 1,4-di­ox­ane mol­ecules which block network formation. In the case of crystals of com­position [Et4N][Cu2(Hhba)2(H0.5hba)2(CH3OH)(H2O)]·2(di­ox­ane), Li[Cu2(Hhba)2(H0.5hba)2(H2O)2]·3(di­ox­ane)·4H2O and [Cu2(Hhba)2(H0.5hba)2(H0.5DABCO)2]·3CH3OH (DABCO is 1,4-di­aza­bicyclo­[2.2.2]octa­ne), square-grid hy­dro­gen-bonded networks are generated in which the complex serves as one type of 4-con­necting node, whilst a second 4-con­necting node is a hy­dro­gen-bonding motif assembled from four phenol/phenolate groups. Another two-dimensional (2D) network based upon a related square-grid structure is formed in the case of [Et4N]2[Cu2(Hhba)2(hba)2(di­ox­ane)2][Cu2(Hhba)4(di­ox­ane)(H2O)]·CH3OH. In [Cu2(Hhba)4(H2O)2]·2(Et4NNO3), a square-grid structure is again apparent, but, in this case, a pair of nitrate anions, along with four phenolic groups and a pair of water mol­ecules, combine to form a second type of 4-con­necting node. When 1,8-bis­(di­methyl­amino)­naphthalene (bdn, `proton sponge') is used as a base, another square-grid network is generated, i.e. [Hbdn]2[Cu2(Hhba)2(hba)2(H2O)2]·3(di­ox­ane)·H2O, but with only the copper dimer complex serving as a 4-con­necting node. Complex three-dimensional networks are formed in [Cu2(Hhba)4(O-bipy)]·H2O and [Cu2(Hhba)4(O-bipy)2]·2(di­ox­ane), where the potentially bridging 4,4'-bi­pyridine N,N'-dioxide (O-bipy) ligand is employed. Rare cases of mixed car­box­yl­ate copper dimer complexes were obtained in the cases of [Cu2(Hhba)3(OAc)(di­ox­ane)]·3.5(di­ox­ane) and [Cu2(Hhba)2(OAc)2(DABCO)2]·10(di­ox­ane), with each structure possessing a 2D network structure. The final com­pound re­por­ted is a simple hy­dro­gen-bonded chain of com­position (H0.5DABCO)(H1.5hba), formed from the reaction of H2hba and DABCO.

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.

3D electron diffraction (3D ED), or microcrystal electron diffraction (MicroED), has become an alternative technique for determining the high-resolution crystal structures of compounds from sub-micron-sized crystals. Here, we considered l-alanine, α-glycine and urea, which are known to form good-quality crystals, and collected high-resolution 3D ED data on our in-house TEM instrument. In this study, we present a comparison of independent atom model (IAM) and transferable aspherical atom model (TAAM) kinematical refinement against experimental and simulated data. TAAM refinement on both experimental and simulated data clearly improves the model fitting statistics (R factors and residual electrostatic potential) compared to IAM refinement. This shows that TAAM better represents the experimental electrostatic potential of organic crystals than IAM. Furthermore, we compared the geometrical parameters and atomic displacement parameters (ADPs) resulting from the experimental refinements with the simulated refinements, with the periodic density functional theory (DFT) calculations and with published X-ray and neutron crystal structures. The TAAM refinements on the 3D ED data did not improve the accuracy of the bond lengths between the non-H atoms. The experimental 3D ED data provided more accurate H-atom positions than the IAM refinements on the X-ray diffraction data. The IAM refinements against 3D ED data had a tendency to lead to slightly longer X—H bond lengths than TAAM, but the difference was statistically insignificant. Atomic displacement parameters were too large by tens of percent for l-alanine and α-glycine. Most probably, other unmodelled effects were causing this behaviour, such as radiation damage or dynamical scattering.

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.

The structure of cis- or trans-bridged [GeF5]− anionic chains have been investigated [Mallouk et al. (1984). Inorg. Chem. 23, 3160–3166] showing the first crystal structures of μ-F-bridged penta­fluoro­germanates. Herein, we report the second crystal structure of trans-penta­fluoro­germanate anions present in the crystal structure of sodium trans-penta­fluoro­germanate(IV) bis­(hy­dro­gen fluoride), Na[GeF5]·2HF. The crystal structure [ortho­rhom­bic Pca21, a = 12.3786 (3), b = 7.2189 (2), c = 11.4969 (3) Å and Z = 8] is built up from infinite chains of trans-linked [GeF6]2− octa­hedra, extending along the b axis and spanning a network of penta­gonal bipyramidal distorted Na-centred polyhedra. These [NaF7] polyhedra are linked in a trans-edge fashion via hy­dro­gen fluoride mol­ecules, in analogy to already known sodium hy­dro­gen fluorides and potassium hy­dro­gen fluorides.

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.

The incommensurately modulated structure of (2S,3S)-2-amino-3-hy­droxy-3-methyl-4-phen­oxy­butanoic acid dihydrate (C11H15NO4·2H2O or I·2H2O) is described in the (3+1)-dimensional superspace group P212121(0β0)000 (β = 0.357). The loss of the three-dimensional periodicity is ascribed to the occupational modulation of one positionally disordered solvent water mol­ecule, where the two positions are related by a small translation [ca 0.666 (9) Å] and ∼168 (5)° rotation about one of its O—H bonds, with an average 0.624 (3):0.376 (3) occupancy ratio. The occupational modulation of this mol­ecule arises due to the com­petition between the different hy­dro­gen-bonding motifs associated with each position. The structure can be very well refined in the average approximation (all satellite reflections disregarded) in the space group P212121, with the water mol­ecule refined as disordered over two positions in a 0.625 (16):0.375 (16) ratio. The refinement in the commensurate threefold supercell approximation in the space group P1121 is also of high quality, with the six corresponding water mol­ecules exhibiting three different occupancy ratios averaging 0.635:0.365.

It is well known that Hirshfeld surfaces provide an easy and straightforward way of analysing inter­molecular inter­actions in the crystal environment. The use of atomic Hirshfeld surfaces has also demonstrated that such surfaces carry information related to chemical bonds which allow a deeper evaluation of the structures. Here we briefly summarize the approach of atomic Hirshfeld surfaces while further evaluating the kind of information that can be retrieved from them. We show that the analysis of the metal-centre Hirshfeld surfaces from structures refined via Hirshfeld Atom Refinement (HAR) allow accurate evaluation of contacts of type M⋯H, and that such contacts can be related to the overall shape of the surfaces. The com­pounds analysed were tetra­aqua­bis­(3-carb­oxy­propionato)metal(II), [M(C4H3O4)2(H2O)4], for metal(II)/M = manganese/Mn, cobalt/Co, nickel/Ni and zinc/Zn. We also evaluate the sensitivity of the surfaces by an investigation of seemingly flat surfaces through analysis of the curvature functions in the direction of C—C bonds. The obtained values not only demonstrate variations in curvature but also show a correlation with the hybridization of the C atoms involved in the bond.

The activation of C—C bonds by transition-metal com­plexes is of continuing inter­est and aceto­nitrile (MeCN) has attracted attention as a cyanide source with com­paratively low toxicity for organic cyanation reactions. A di­iron end-on μ-η1:η1-CN-bridged com­plex was obtained from a crystallization experiment of an open-chain iron–NHC com­plex, namely, μ-cyanido-κ2C:N-bis­{[(aceto­nitrile-κN)[3,3'-bis­(pyridin-2-yl)-1,1'-(methyl­idene)bis­(benzimidazol-2-yl­idene)]iron(II)} tris­(hexa­fluoro­phos­phate), [Fe2(CN)(C2H3N)2(C25H18N6)2](PF6)3. The cyanide appears to originate from the MeCN solvent by C—C bond cleavage or through carbon–hy­dro­gen oxidation.

Herein we report the crystal structures of two ben­zo­di­az­e­pines obtained by reacting N,N'-(4,5-di­amino-1,2-phenyl­ene)bis­(4-methyl­ben­zene­sul­fon­am­ide) (1) or 4,5-(4-methyl­ben­zene­sul­fon­am­ido)­ben­zene-1,2-diaminium dichloride (1·2HCl) with acetone, giving 2,2,4-trimethyl-8,9-bis­(4-methyl­ben­zene­sul­fon­am­ido)-2,3-di­hydro-5H-1,5-ben­zo­di­az­e­pine, C26H30N4O4S2 (2), and 2,2,4-tri­methyl-8,9-bis­(4-methyl­ben­zene­sul­fon­am­ido)-2,3-di­hydro-5H-1,5-ben­zo­di­az­e­pin-1-ium chloride 0.3-hydrate, C26H31N4O4S2+·Cl−·0.3H2O (3). Compounds 2 and 3 were first obtained in attempts to recrystallize 1 and 1·2HCl using acetone as solvent. This solvent reacted with the vicinal di­amines present in the mol­ecular structures, forming a 5H-1,5-ben­zo­di­az­e­pine ring. In the crystal structure of 2, the seven-membered ring of ben­zo­di­az­e­pine adopts a boat-like conformation, while upon protonation, observed in the crystal structure of 3, it adopts an envelope-like conformation. In both crystalline com­pounds, the tosyl­amide N atoms are not in resonance with the arene ring, mainly due to hy­dro­gen bonds and steric hindrance caused by the large vicinal groups in the aromatic ring. At a supra­molecular level, the crystal structure is maintained by a combination of hy­dro­gen bonds and hydro­phobic inter­actions. In 2, amine-to-tosyl N—H⋯O and amide-to-imine N—H⋯N hy­dro­gen bonds can be observed. In contrast, in 3, the chloride counter-ion and water mol­ecule result in most of the hy­dro­gen bonds being of the amide-to-chloride and ammonium-to-chloride N—H⋯Cl types, while the amine inter­acts with the tosyl group, as seen in 2. In conclusion, we report the synthesis of 1, 1·2HCl and 2, as well as their chemical characterization. For 2, two synthetic methods are described, i.e. solvent-mediated crystallization and synthesis via a more efficient and cleaner route as a polycrystalline material. Salt 3 was only obtained as presented, with only a few crystals being formed.

Treating the amide acetanilide (N-phenyl­acetamide, C8H9NO) with aqueous strong acids allowed the structures of five hemi-protonated salt forms of acetanilide to be elucidated. N-(1-Hy­droxy­ethyl­idene)anilinium chloride–N-phenyl­acetamide (1/1), [(C8H9NO)2H][Cl], and the bromide, [(C8H9NO)2H][Br], triiodide, [(C8H9NO)2H][I3], tetra­fluoro­borate, [(C8H9NO)2H][BF4], and di­iodo­bromide hemi(diiodine), [(C8H9NO)2H][I2Br]·0.5I2, analogues all feature centrosymmetric dimeric units linked by O—H⋯O hy­dro­gen bonds that extend into one-dimensional hy­dro­gen-bonded chains through N—H⋯X inter­actions, where X is the halide atom of the anion. Protonation occurs at the amide O atom and results in systematic lengthening of the C=O bond and a corresponding shortening of the C—N bond. The size of these geometric changes is similar to those found for hemi-protonated paracetamol structures, but less than those in fully protonated paracetamol structures. The bond angles of the amide fragments are also found to change on protonation, but these angular changes are also influenced by conformation, namely, whether the amide group is coplanar with the phenyl ring or twisted out of plane.

Three structurally diverse 5-phenyl­tetra­zolato (Tz) Ti, Zr, and Ta com­plexes, namely, (C2H8N)[Ti2(C7H5N4)5(C2H6N)4]·1.45C6H6 or (Me2NH2)[Ti2(NMe2)4(2,3-μ-Tz)3(2-η1-Tz)2]·1.45C6H6, (1·1.45C6H6), [Zr2(C7H5N4)6(C2H6N)2(C2H7N)2]·1.12C6H6·0.382CH2Cl2 or [Zr2(Me2NH)2(NMe2)2(2,3-μ-Tz)3(2-η1-Tz)2(1,2-η2-Tz)]·1.12C6H6·0.38CH2Cl2 (2·1.12C6H6·0.38CH2Cl2), and (C2H8N)2[Ta2(C7H5N4)8(C2H6N)2O]·0.25C7H8 or (Me2NH2)2[Ta2(NMe2)2(2,3-μ-Tz)2(2-η1-Tz)6O]·0.25C7H8 (3·0.25C7H8), where TzH is 5-phenyl-1H-tetra­zole, have been synthesized and structurally characterized. All three com­plexes are dinuclear; the Ti center in 1 is six-coordinate, whereas the Zr and Ta atoms in 2 and 3 are seven-coordinate. The coordination environments of the Ti centers in 1 are similar, and so are the ligations of the Ta centers in 3. In contrast, the two Zr centers in 2 bear a different number of ligands, one of which is a bidentate η2-5-phenyl­tetra­zolato ligand that has not been observed previously for d-block elements. The di­methyl­amido ligand, present in the starting materials, remained un­changed, or was converted to di­methyl­amine and di­methyl­ammonium during the synthesis. Di­methyl­amine coordinates as a neutral ligand, whereas di­methyl­ammonium is retained as a hy­dro­gen-bonded entity bridging Tz ligands.