m K0.72Na1.71Ca5.79Si6O19 – the first oligosilicate based on [Si6O19]-hexamers and its stability compared to cyclosilicates By journals.iucr.org Published On :: 2024-08-30 Synthesis experiments were conducted in the quaternary system K2O–Na2O–CaO–SiO2, resulting in the formation of a previously unknown compound with the composition K0.72Na1.71Ca5.79Si6O19. Single crystals of sufficient size and quality were recovered from a starting mixture with a K2O:Na2O:CaO:SiO2 molar ratio of 1.5:0.5:2:3. The mixture was confined in a closed platinum tube and slowly cooled from 1150°C at a rate of 0.1°C min−1 to 700°C before being finally quenched in air. The structure has tetragonal symmetry and belongs to space group P4122 (No. 91), with a = 7.3659 (2), c = 32.2318 (18) Å, V = 1748.78 (12) Å3, and Z = 4. The silicate anion consists of highly puckered, unbranched six-membered oligomers with the composition [Si6O19] and point group symmetry 2 (C2). Although several thousands of natural and synthetic oxosilicates have been structurally characterized, this compound is the first representative of a catena-hexasilicate anion, to the best of our knowledge. Structural investigations were completed using Raman spectroscopy. The spectroscopic data was interpreted and the bands were assigned to certain vibrational species with the support of density functional theory at the HSEsol level of theory. To determine the stability properties of the novel oligosilicate compared to those of the chemically and structurally similar cyclosilicate combeite, we calculated the electronegativity of the respective structures using the electronegativity equalization method. The results showed that the molecular electronegativity of the cyclosilicate was significantly higher than that of the oligostructure due to the different connectivities of the oxygen atoms within the molecular units. Full Article text
m Magnetic space groups versus representation analysis in the investigation of magnetic structures: the happy end of a strained relationship By journals.iucr.org Published On :: 2024-09-10 In recent decades, sustained theoretical and software developments have clearly established that representation analysis and magnetic symmetry groups are complementary concepts that should be used together in the investigation and description of magnetic structures. Historically, they were considered alternative approaches, but currently, magnetic space groups and magnetic superspace groups can be routinely used together with representation analysis, aided by state-of-the-art software tools. After exploring the historical antagonism between these two approaches, we emphasize the significant advancements made in understanding and formally describing magnetic structures by embracing their combined use. Full Article text
m On the magnetic and crystal structures of NiO and MnO By journals.iucr.org Published On :: 2024-09-10 The magnetic and crystal structures of manganese and nickel monoxides have been studied using high-resolution neutron diffraction. The known 1k-structures based on the single propagation vector [½ ½ ½] for the parent paramagnetic space group Fm3m are forced to have monoclinic magnetic symmetry and are not possible in rhombohedral symmetry. However, the monoclinic distortions from the rhombohedral crystal metric allowed by symmetry are very small, and the explicit monoclinic splittings of the diffraction peaks have not been experimentally observed. We analyse the magnetic crystallographic models metrically compatible with our experimental data in full detail by using isotropy subgroup representation approach, including rhombohedral solutions based on the propagation vector star {[½ ½ ½], [−½ ½ ½], [½−½ ½], [½ ½ −½]}. Although the full star rhombohedral RI3c structure can equally well fit our diffraction data for NiO, we conclude that the best solution for the crystal and magnetic structures for NiO and MnO is the 1k monoclinic model with the magnetic space group Cc2/c (Belov–Neronova–Smirnova No. 15.90, UNI symbol C2/c.1'c[C2/m]). Full Article text
m A comprehensive characterization of thiophosgene in the solid state By journals.iucr.org Published On :: 2024-09-05 Thiophosgene is one of the principal C=S building blocks in synthetic chemistry. At room temperature, thiophosgene is a red liquid. While its properties in the liquid and gaseous states are well known, a comprehensive characterization of thiophosgene in its solid state is presented here. Differential scanning calorimetry shows that thiophosgene forms a supercooled melt before rapidly crystallizing. Its melting point is 231.85 K (−41.3 °C). At 80 K, thiophosgene crystallizes in space group P63/m [No. 174, a = b = 5.9645 (2), c = 6.2835 (3) Å, V = 193.59 (2) Å3]. The molecule shows a distinct rotational disorder: all S and Cl positions are of mixed occupancy and the disorder does not resolve at temperatures as low as 10 K, as was shown by neutron powder diffraction. Infrared, Raman and inelastic neutron scattering spectra were collected and assigned with the aid of quantum chemical calculations. A larger ordered structural model allowed for better agreement between the measured and calculated spectra, further indicating that disorder is an inherent feature of solid-state thiophosgene. Full Article text
m Analysis of magnetic structures in JANA2020 By journals.iucr.org Published On :: 2024-09-19 JANA2020 is a program developed for the solution and refinement of regular, twinned, modulated, and composite crystal structures. In addition, JANA2020 also includes a magnetic option for solving magnetic structures from powder and single-crystal neutron diffraction data. This tool uses magnetic space and superspace symmetry to describe commensurate and incommensurate magnetic structures. The basics of the underlying formulation of magnetic structure factors and the use of magnetic symmetry for handling modulated and non-modulated magnetic structures are presented here, together with the general features of the magnetic tool. Examples of structures solved in the magnetic option of JANA2020 are given to illustrate the operation and capabilities of the program. Full Article text
m Search for missing symmetry in the Inorganic Crystal Structure Database (ICSD) By journals.iucr.org Published On :: 2024-09-17 An exhaustive search for missing symmetry was performed for 223 076 entries in the ICSD (2023-2 release). Approximately 0.65% of them can be described with higher symmetry than reported. Out of the identified noncentrosymmetric entries, ∼74% can be described by centrosymmetric space groups; this has implications for compatible physical properties. It is proposed that the information on the correct space group is included in the ICSD. Full Article text
m Determining magnetic structures in GSAS-II using the Bilbao Crystallographic Server tool k-SUBGROUPSMAG By journals.iucr.org Published On :: 2024-09-20 The embedded call to a special version of the web-based Bilbao Crystallographic Server tool k-SUBGROUPSMAG from within GSAS-II to form a list of all possible commensurate magnetic subgroups of a parent magnetic grey group is described. It facilitates the selection and refinement of the best commensurate magnetic structure model by having all the analysis tools including Rietveld refinement in one place as part of GSAS-II. It also provides the chosen magnetic space group as one of the 1421 possible standard Belov–Neronova–Smirnova forms or equivalent non-standard versions. Full Article text
m Crystal structure of N-terminally hexahistidine-tagged Onchocerca volvulus macrophage migration inhibitory factor-1 By journals.iucr.org Published On :: 2024-11-06 Onchocerca volvulus causes blindness, onchocerciasis, skin infections and devastating neurological diseases such as nodding syndrome. New treatments are needed because the currently used drug, ivermectin, is contraindicated in pregnant women and those co-infected with Loa loa. The Seattle Structural Genomics Center for Infectious Disease (SSGCID) produced, crystallized and determined the apo structure of N-terminally hexahistidine-tagged O. volvulus macrophage migration inhibitory factor-1 (His-OvMIF-1). OvMIF-1 is a possible drug target. His-OvMIF-1 has a unique jellyfish-like structure with a prototypical macrophage migration inhibitory factor (MIF) trimer as the `head' and a unique C-terminal `tail'. Deleting the N-terminal tag reveals an OvMIF-1 structure with a larger cavity than that observed in human MIF that can be targeted for drug repurposing and discovery. Removal of the tag will be necessary to determine the actual biological oligomer of OvMIF-1 because size-exclusion chomatographic analysis of His-OvMIF-1 suggests a monomer, while PISA analysis suggests a hexamer stabilized by the unique C-terminal tails. Full Article text
m Crystal structure of S-n-octyl 3-(1-phenylethylidene)dithiocarbazate and of its bis-chelated nickel(II) complex By journals.iucr.org Published On :: 2023-11-14 The nitrogen–sulfur Schiff base proligand S-n-octyl 3-(1-phenylethylidene)dithiocarbazate, C17H26N2S2 (HL), was prepared by reaction of S-octyl dithiocarbamate with acetophenone. Treatment of HL with nickel acetate yielded the complex bis[S-n-octyl 3-(1-phenylethylidene)dithiocarbazato]nickel(II), [Ni(C17H25N2S2)2] (NiL2), which was shown to adopt a tetrahedrally distorted cis-square-planar coordination geometry, with the NiSN planes of the two ligands forming a dihedral angle of 21.66 (6)°. Changes in the geometry of the L ligand upon chelation of Ni2+ are described, involving a ca 180° rotation around the N(azomethine)—C(thiolate) bond. Full Article text
m Crystal structures of the isotypic complexes bis(morpholine)gold(I) chloride and bis(morpholine)gold(I) bromide By journals.iucr.org Published On :: 2023-11-16 The compounds bis(morpholine-κN)gold(I) chloride, [Au(C4H9NO)2]Cl, 1, and bis(morpholine-κN)gold(I) bromide, [Au(C4H9NO)2]Br, 2, crystallize isotypically in space group C2/c with Z = 4. The gold atoms, which are axially positioned at the morpholine rings, lie on inversion centres (so that the N—Au—N coordination is exactly linear) and the halide anions on twofold axes. The residues are connected by a classical hydrogen bond N—H⋯halide and by a short gold⋯halide contact to form a layer structure parallel to the bc plane. The morpholine oxygen atom is not involved in classical hydrogen bonding. Full Article text
m Crystal structure of polymeric bis(3-amino-1H-pyrazole)cadmium dibromide By journals.iucr.org Published On :: 2023-11-14 The reaction of cadmium bromide tetrahydrate with 3-aminopyrazole (3-apz) in ethanolic solution leads to tautomerization of the ligand and the formation of crystals of the title compound, catena-poly[[dibromidocadmium(II)]-bis(μ-3-amino-1H-pyrazole)-κ2N3:N2;κ2N2:N3], [CdBr2(C3H5N3)2]n or [CdBr2(3-apz)2]n. Its asymmetric unit consists of a half of a Cd2+ cation, a bromide anion and a 3-apz molecule. The Cd2+ cations are coordinated by two bromide anions and two 3-apz ligands, generating trans-CdN4Br2 octahedra, which are linked into chains by pairs of the bridging ligands. In the crystal, the ligand molecules and bromide anions of neighboring chains are linked through interchain hydrogen bonds into a two-dimensional network. The intermolecular contacts were quantified using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing the relative quantitative contributions of the weak intermolecular contacts. Full Article text
m Crystal structure reinvestigation and spectroscopic analysis of tricadmium orthophosphate By journals.iucr.org Published On :: 2023-11-14 Single crystals of tricadmium orthophosphate, Cd3(PO4)2, have been synthesized successfully by the hydrothermal route, while its powder form was obtained by a solid-solid process. The corresponding crystal structure was determined using X-ray diffraction data in the monoclinic space group P21/n. The crystal structure consists of Cd2O8 or Cd2O10 dimers linked together by PO4 tetrahedra through sharing vertices or edges. Scanning electron microscopy (SEM) was used to investigate the morphology and to confirm the chemical composition of the synthesized powder. Infrared analysis corroborates the presence of isolated phosphate tetrahedrons in the structure. UV–Visible studies showed an absorbance peak at 289 nm and a band gap energy of 3.85 eV, as determined by the Kubelka–Munk model. Full Article text
m Crystal structure and Hirshfeld surface analysis of (2Z)-3-oxo-N-phenyl-2-[(1H-pyrrol-2-yl)methylidene]butanamide monohydrate By journals.iucr.org Published On :: 2023-11-14 In the title compound, C15H14N2O2·H2O, the 1H-pyrrole ring makes a dihedral angle of 59.95 (13)° with the phenyl ring. In the crystal, the molecules are connected by C—H⋯O hydrogen bonds into layers parallel to the (020) plane, while two molecules are connected to the water molecule by two N—H⋯O hydrogen bonds and one molecule by an O—H⋯O hydrogen bond. C—H⋯π and π–π interactions further link the molecules into chains extending in the [overline{1}01] direction and stabilize the molecular packing. According to a Hirshfeld surface study, H⋯H (49.4%), C⋯H/H⋯C (23.2%) and O⋯H/H⋯O (20.0%) interactions are the most significant contributors to the crystal packing. Full Article text
m Synthesis and crystal structures of two related Co and Mn complexes: a celebration of collaboration between the universities of Dakar and Southampton By journals.iucr.org Published On :: 2023-11-16 We report the synthesis and structures of two transition-metal complexes involving 2-(2-hydroxyphenyl)benzimidazole (2hpbi – a ligand of interest for its photoluminescent applications), with cobalt, namely, bis[μ-2-(1H-1,3-benzodiazol-2-yl)phenolato]bis[ethanol(thiocyanato)cobalt(II)], [Co2(C13H9N2O)2(NCS)2(C2H6O)2], (1), and manganese, namely, bis[μ-2-(1H-1,3-benzodiazol-2-yl)phenolato]bis{[2-(1H-1,3-benzodiazol-2-yl)phenolato](thiocyanato)manganese(III)} dihydrate, [Mn2(C13H9N2O)4(NCS)2]·2H2O, (2). These structures are two recent examples of a fruitful collaboration between researchers at the Laboratoire de Chimie de Coordination Organique/Organic Coordination Chemistry Laboratory (LCCO), University of Dakar, Senegal and the National Crystallography Service (NCS), School of Chemistry, University Southampton, UK. This productive partnership was forged through meeting at Pan-African Conferences on Crystallography and quickly grew as the plans for the AfCA (African Crystallographic Association) developed. This article therefore also showcases this productive partnership, in celebration of the IUCr's 75 year anniversary and the recent inclusion of AfCA as a Regional Associate of the IUCr. Full Article text
m Synthesis, structure and Hirshfeld surface analysis of 1,3-bis[(1-octyl-1H-1,2,3-triazol-4-yl)methyl]-1H-benzo[d]imidazol-2(3H)-one By journals.iucr.org Published On :: 2023-11-21 The title molecule, C29H44N8O, adopts a conformation resembling a two-bladed fan with the octyl chains largely in fully extended conformations. In the crystal, C—H⋯O hydrogen bonds form chains of molecules extending along the b-axis direction, which are linked by weak C—H⋯N hydrogen bonds and C—H⋯π interactions to generate a three-dimensional network. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (68.3%), H⋯N/N⋯H (15.7%) and H⋯C/C⋯H (10.4%) interactions. Full Article text
m Synthesis, crystal structure and Hirshfeld analysis of trans-bis(2-{1-[(6R,S)-3,5,5,6,8,8-hexamethyl-5,6,7,8-tetrahydronaphthalen-2-yl]ethylidene}-N-methylhydrazinecarbothioamidato-κ2N2,S)palladium(II) ethanol mon By journals.iucr.org Published On :: 2023-11-16 The reaction between the (R,S)-fixolide 4-methylthiosemicarbazone and PdII chloride yielded the title compound, [Pd(C20H30N3S)2]·C2H6O {common name: trans-bis[(R,S)-fixolide 4-methylthiosemicarbazonato-κ2N2S]palladium(II) ethanol monosolvate}. The asymmetric unit of the title compound consists of one bis-thiosemicarbazonato PdII complex and one ethanol solvent molecule. The thiosemicarbazononato ligands act as metal chelators with a trans configuration in a distorted square-planar geometry. A C—H⋯S intramolecular interaction, with graph-set motif S(6), is observed and the coordination sphere resembles a hydrogen-bonded macrocyclic environment. Additionally, one C—H⋯Pd anagostic interaction can be suggested. Each ligand is disordered over the aliphatic ring, which adopts a half-chair conformation, and two methyl groups [s.o.f. = 0.624 (2):0.376 (2)]. The disorder includes the chiral carbon atoms and, remarkably, one ligand has the (R)-isomer with the highest s.o.f. value atoms, while the other one shows the opposite, the atoms with the highest s.o.f. value are associated with the (S)-isomer. The N—N—C(=S)—N fragments of the ligands are approximately planar, with the maximum deviations from the mean plane through the selected atoms being 0.0567 (1) and −0.0307 (8) Å (r.m.s.d. = 0.0403 and 0.0269 Å) and the dihedral angle with the respective aromatic rings amount to 46.68 (5) and 50.66 (4)°. In the crystal, the complexes are linked via pairs of N—H⋯S interactions, with graph-set motif R22(8), into centrosymmetric dimers. The dimers are further connected by centrosymmetric pairs of ethanol molecules, building mono-periodic hydrogen-bonded ribbons along [011]. The Hirshfeld surface analysis indicates that the major contributions for the crystal cohesion are [atoms with highest/lowest s.o.f.s considered separately]: H⋯H (81.6/82.0%), H⋯C/C⋯H (6.5/6.4%), H⋯N/N⋯H (5.2/5.0%) and H⋯S/S⋯H (5.0/4.9%). Full Article text
m Crystal structure, Hirshfeld surface analysis, intermolecular interaction energies, energy frameworks and DFT calculations of 4-amino-1-(prop-2-yn-1-yl)pyrimidin-2(1H)-one By journals.iucr.org Published On :: 2023-11-21 In the title molecule, C7H7N3O, the pyrimidine ring is essentially planar, with the propynyl group rotated out of this plane by 15.31 (4)°. In the crystal, a tri-periodic network is formed by N—H⋯O, N—H⋯N and C—H⋯O hydrogen-bonding and slipped π–π stacking interactions, leading to narrow channels extending parallel to the c axis. Hirshfeld surface analysis of the crystal structure reveals that the most important contributions for the crystal packing are from H⋯H (36.2%), H⋯C/C⋯H (20.9%), H⋯O/O⋯H (17.8%) and H⋯N/N⋯H (12.2%) interactions, showing that hydrogen-bonding and van der Waals interactions are the dominant interactions in the crystal packing. Evaluation of the electrostatic, dispersion and total energy frameworks indicates that the stabilization is dominated by the electrostatic energy contributions. The molecular structure optimized by density functional theory (DFT) calculations at the B3LYP/6–311 G(d,p) level is compared with the experimentally determined structure in the solid state. The HOMO–LUMO behaviour was also elucidated to determine the energy gap. Full Article text
m Synthesis, crystal structure and hydrogenation properties of MgxLi3 − xB48 − y (x = 1.11, y = 0.40) By journals.iucr.org Published On :: 2024-01-01 The ternary magnesium/lithium boride, MgxLi3 − xB48 − y (x = 1.11, y = 0.40, idealized formula MgLi2B48), crystallizes as its own structure type in P43212, which is closely related to the structural family comprising α-AlB12, Be0.7Al1.1B22 and tetragonal β-boron. The asymmetric unit of title structure contains two statistical mixtures Mg/Li in Wyckoff sites 8b with relative occupancies Mg:Li = 0.495 (9):0.505 (9) and 4a with Mg:Li = 0.097 (8):0.903 (8). The boron atoms occupy 23 8b sites and two 4a sites. One of the latter sites has a partial occupancy factor of 0.61 (2). Both unique Mg/Li atoms adopt a twelvefold coordination environment in the form of truncated tetrahedra (Laves polyhedra). These polyhedra are connected by triangular faces to four [B12] icosahedra. The boron atoms exhibit four kinds of polyhedra, namely pentagonal pyramid (coordination number CN = 6), distorted tetragonal pyramid (CN = 5), bicapped hexagon (CN = 8) and gyrobifastigium (CN = 8). At the gas hydrogenation of MgLi2B48 alloy, formation of the eutectic composite hydride LiBH4+Mg(BH4)2 and amorphous boron is observed. In the temperature range 543–623 K, the hydride eutectics decompose, forming MgH2, LiH, MgB4, B and H2. Full Article text
m Synthesis, crystal structure and Hirshfeld surface analysis of the tetrakis complex NaNdPyr4(i-PrOH)2·i-PrOH with a carbacylamidophosphate of the amide type By journals.iucr.org Published On :: 2023-11-30 The tetrakis complex of neodymium(III), tetrakis{μ-N-[bis(pyrrolidin-1-yl)phosphoryl]acetamidato}bis(propan-2-ol)neodymiumsodium propan-2-ol monosolvate, [NaNd(C10H16Cl3N3O2)4(C3H8O)2]·C3H8O or NaNdPyr4(i-PrOH)2·i-PrOH, with the amide type CAPh ligand bis(N,N-tetramethylene)(trichloroacetyl)phosphoric acid triamide (HPyr), has been synthesized, crystallized and characterized by X-ray diffraction. The complex does not have the tetrakis(CAPh)lanthanide anion, which is typical for ester-type CAPh-based coordination compounds. Instead, the NdO8 polyhedron is formed by one oxygen atom of a 2-propanol molecule and seven oxygen atoms of CAPh ligands in the title compound. Three CAPh ligands are coordinated in a bidentate chelating manner to the NdIII ion and simultaneously binding the sodium cation by μ2-bridging PO and CO groups while the fourth CAPh ligand is coordinated to the sodium cation in a bidentate chelating manner and, due to the μ2-bridging function of the PO group, also binds the neodymium ion. Full Article text
m An octanuclear nickel(II) pyrazolate cluster with a cubic Ni8 core and its methyl- and n-octyl-functionalized derivatives By journals.iucr.org Published On :: 2023-11-30 The molecular and crystal structure of a discrete [Ni8(μ4-OH)6(μ-4-Rpz)12]2− (R = H; pz = pyrazolate anion, C3H3N2−) cluster with an unprecedented, perfectly cubic arrangement of its eight Ni centers is reported, along with its lower-symmetry alkyl-functionalized (R = methyl and n-octyl) derivatives. Crystals of the latter two were obtained with two identical counter-ions (Bu4N+), whereas the crystal of the complex with the parent pyrazole ligand has one Me4N+ and one Bu4N+ counter-ion. The methyl derivative incorporates 1,2-dichloroethane solvent molecules in its crystal structure, whereas the other two are solvent-free. The compounds are tetrabutylazanium tetramethylazanium hexa-μ4-hydroxido-dodeca-μ2-pyrazolato-hexahedro-octanickel, (C16H36N)(C4H12N)[Ni8(C3H3N2)12(OH)6] or (Bu4N)(Me4N)[Ni8(μ4-OH)6(μ-pz)12] (1), bis(tetrabutylazanium) hexa-μ4-hydroxido-dodeca-μ2-(4-methylpyrazolato)-hexahedro-octanickel 1,2-dichloroethane 7.196-solvate, (C16H36N)2[Ni8(C4H5N2)12(OH)6]·7.196C2H4Cl2 or (Bu4N)2[Ni8(μ4-OH)6(μ-4-Mepz)12]·7.196(ClCH2CH2Cl) (2), and bis(tetrabutylazanium) hexa-μ4-hydroxido-dodeca-μ2-(4-octylpyrazolato)-hexahedro-octanickel, (C16H36N)2[Ni8(C11H19N2)12(OH)6] or (Bu4N)2[Ni8(μ4-OH)6(μ-4-nOctpz)12] (3). All counter-ions are disordered (with the exception of one Bu4N+ in 3). Some of the octyl chains of 3 (the crystal is twinned by non-merohedry) are also disordered. Various structural features are discussed and contrasted with those of other known [Ni8(μ4-OH)6(μ-4-Rpz)12]2− complexes, including extended three-dimensional metal–organic frameworks. In all three structures, the Ni8 units are lined up in columns. Full Article text
m Crystal structure and antimycobacterial evaluation of 2-(cyclohexylmethyl)-7-nitro-5-(trifluoromethyl)benzo[d]isothiazol-3(2H)-one By journals.iucr.org Published On :: 2023-11-30 The title compound, C15H15F3N2O3S, crystallizes in the monoclinic system, space group I2/a, with Z = 8. As expected, the nine-membered heterobicyclic system is virtually planar and the cyclohexyl group adopts a chair conformation. There is structural evidence for intramolecular N—S⋯O chalcogen bonding between the benzisothiazolinone S atom and one O atom of the nitro group, approximately aligned along the extension of the covalent N—S bond [N—S⋯O = 162.7 (1)°]. In the crystal, the molecules form centrosymmetric dimers through C—H⋯O weak hydrogen bonding between a C—H group of the electron-deficient benzene ring and the benzothiazolinone carbonyl O atom with an R22(10) motif. In contrast to the previously described N-acyl 7-nitro-5-(trifluoromethyl)benzo[d]isothiazol-3(2H)-ones, the title N-cyclohexylmethyl analogue does not inhibit growth of Mycobacterium aurum and Mycobacterium smegmatis in vitro. Full Article text
m Synthesis, crystal structure and Hirshfeld surface analysis of a cadmium complex of naphthalene-1,5-disulfonate and o-phenylenediamine By journals.iucr.org Published On :: 2023-11-30 A novel o-phenylenediamine (opda)-based cadmium complex, bis(benzene-1,2-diamine-κ2N,N')bis(benzene-1,2-diamine-κN)cadmium(II) naphthalene-1,5-disulfonate, [Cd(C6H8N2)4](C10H6O6S2), was synthesized. The complex salt crystallizes in the monoclinic space group C2/c. The Cd atom occupies a special position and coordinates six nitrogen atoms from four o-phenylenediamine molecules, two as chelating ligands and two as monodentate ligands. The amino H atoms of opda interact with two O atoms of the naphthalene-1,5-disulfonate anions. The anions act as bridges between [Cd(opda)4]2+ cations, forming a two-dimensional network in the [010] and [001] directions. The Hirshfeld surface analysis shows that the primary factors contributing to the supramolecular interactions are short contacts, particularly van der Waals forces of the type H⋯H, O⋯H and C⋯H. Full Article text
m Synthesis and redetermination of the crystal structure of NbF5 By journals.iucr.org Published On :: 2023-11-30 Single crystals of NbF5, niobium(V) fluoride, have been obtained by the reaction of niobium metal in a stream of dilute elemental fluorine at 473 K and subsequent sublimation. The as-obtained bulk phase compound was shown to be pure by powder X-ray diffraction at 293 K and by IR and Raman spectroscopy. A single-crystal X-ray analysis was conducted at 100 K. In comparison to the previously reported structure model [Edwards (1964). J. Chem. Soc. pp. 3714–3718], the lattice parameters and fractional atom coordinates were determined to much higher precision and individual, anisotropic displacement parameters were refined for all atoms. Full Article text
m Synthesis, crystal structure and computational analysis of 2,7-bis(4-chlorophenyl)-3,3-dimethyl-1,4-diazepan-5-one By journals.iucr.org Published On :: 2023-11-30 In the title compound, C19H20Cl2N2O, the seven-membered 1,4-diazepane ring adopts a chair conformation while the 4-chlorophenyl substituents adopt equatorial orientations. The chlorophenyl ring at position 7 is disordered over two positions [site occupancies 0.480 (16):0.520 (16)]. The dihedral angle between the two benzene rings is 63.0 (4)°. The methyl groups at position 3 have an axial and an equatorial orientation. The compound exists as a dimer exhibiting intermolecular N—H⋯O hydrogen bonding with R22(8) graph-set motifs. The crystal structure is further stabilized by C—H⋯O hydrogen bonds together with two C—Cl⋯π (ring) interactions. The geometry was optimized by DFT using the B3LYP/6–31 G(d,p) level basis set. In addition, the HOMO and LUMO energies, chemical reactivity parameters and molecular electrostatic potential were calculated at the same level of theory. Hirshfeld surface analysis indicated that the most important contributions to the crystal packing are from H⋯H (45.6%), Cl⋯H/H⋯Cl (23.8%), H⋯C/C⋯H (12.6%), H⋯O/O⋯H (8.7%) and C⋯Cl/Cl⋯C (7.1%) interactions. Analysis of the interaction energies showed that the dispersion energy is greater than the electrostatic energy. A crystal void volume of 237.16 Å3 is observed. A molecular docking study with the human oestrogen receptor 3ERT protein revealed good docking with a score of −8.9 kcal mol−1. Full Article text
m Dimorphism of [Bi2O2(OH)](NO3) – the ordered Pna21 structure at 100 K By journals.iucr.org Published On :: 2023-11-30 The re-investigation of [Bi2O2(OH)](NO3), dioxidodibismuth(III) hydroxide nitrate, on the basis of single-crystal X-ray diffraction data revealed an apparent structural phase transition of a crystal structure determined previously (space group Cmc21 at 173 K) to a crystal structure with lower symmetry (space group Pna21 at 100 K). The Cmc21 → Pna21 group–subgroup relationship between the two crystal structures is klassengleiche with index 2. In contrast to the crystal structure in Cmc21 with orientational disorder of the nitrate anion, disorder does not occur in the Pna21 structure. Apart from the disorder of the nitrate anion, the general structural set-up in the two crystal structures is very similar: [Bi2O2]2+ layers extend parallel to (001) and alternate with layers of (OH)− anions above and (NO3)− anions below the cationic layer. Whereas the (OH)− anion shows strong bonds to the BiIII cations, the (NO3)− anion weakly binds to the BiIII cations of the cationic layer. A rather weak O—H⋯O hydrogen-bonding interaction between the (OH)− anion and the (NO3)− anion links adjacent sheets along [001]. Full Article text
m New copper carboxylate pyrene dimers: synthesis, crystal structure, Hirshfeld surface analysis and electrochemical characterization By journals.iucr.org Published On :: 2024-01-01 Two new copper dimers, namely, bis(dimethyl sulfoxide)tetrakis(μ-pyrene-1-carboxylato)dicopper(Cu—Cu), [Cu2(C17H9O2)4(C2H6OS)2] or [Cu2(pyr-COO−)4(DMSO)2] (1), and bis(dimethylformamide)tetrakis(μ-pyrene-1-carboxylato)dicopper(Cu—Cu), [Cu2(C17H9O2)4(C3H7NO)2] or [Cu2(pyr-COO−)4(DMF)2] (2) (pyr = pyrene), were synthesized from the reaction of pyrene-1-carboxylic acid, copper(II) nitrate and triethylamine from solvents DMSO and DMF, respectively. While 1 crystallized in the space group Poverline{1}, the crystal structure of 2 is in space group P21/n. The Cu atoms have octahedral geometries, with four oxygen atoms from carboxylate pyrene ligands occupying the equatorial positions, a solvent molecule coordinating at one of the axial positions, and a Cu⋯Cu contact in the opposite position. The packing in the crystal structures exhibits π–π stacking interactions and short contacts through the solvent molecules. The Hirshfeld surfaces and two-dimensional fingerprint plots were generated for both compounds to better understand the intermolecular interactions and the contribution of heteroatoms from the solvent ligands to the crystal packing. In addition, a Cu2+/Cu1+ quasi-reversible redox process was identified for compound 2 using cyclic voltammetry that accounts for a diffusion-controlled electron-donation process to the Cu dimer. Full Article text
m Crystal structure and Hirshfeld surface analysis of a new benzimidazole compound, 3-{1-[(2-hydroxyphenyl)methyl]-1H-1,3-benzodiazol-2-yl}phenol By journals.iucr.org Published On :: 2024-01-01 The title compound, C20H16N2O2, is composed of two monosubstituted benzene rings and one benzimidazole unit. The benzimidazole moiety subtends dihedral angles of 46.16 (7) and 77.45 (8)° with the benzene rings, which themselves form a dihedral angle of 54.34 (9)°. The crystal structure features O—H⋯N and O—H⋯O hydrogen-bonding interactions, which together lead to the formation of two-dimensional hydrogen-bonded layers parallel to the (101) plane. In addition, π–π interactions also contribute to the crystal cohesion. Hirshfeld surface analysis indicates that the most significant contacts in the crystal packing are: H⋯H (47.5%), O⋯H/H⋯O (12.4%), N⋯H/H⋯N (6.1%), C⋯H/H⋯C (27.6%) and C⋯C (4.6%). Full Article text
m Crystal structure of [1,3-bis(2,4,6-trimethylphenyl)imidazolidin-2-ylidene]dichlorido(2-{[(2-methoxyethyl)(methyl)amino]methyl}benzylidene)ruthenium By journals.iucr.org Published On :: 2024-01-01 The title compound, [RuCl2(C33H43N3O)], is an example of a new generation of N,N-dialkyl ruthenium catalysts with an N—Ru coordination bond as part of a six-membered chelate ring. The Ru atom has an Addison τ parameter of 0.244, which indicates a geometry intermediate between square-based pyramidal and trigonal–bipyramidal. The complex shows the usual trans arrangement of the two chlorides, with Ru—Cl bond lengths of 2.3515 (8) and 2.379 (7) Å, and a Cl—Ru—Cl angle of 158.02 (3)°. One of the chlorine atoms and the atoms of the 2-methoxy-N-methyl-N-[(2-methylphenyl)methyl]ethane-1-amine group of the title complex display disorder over two positions in a 0.889 (2): 0.111 (2) ratio. Full Article text
m The synthesis and structural properties of a chloridobis{N-[(4-methoxyphenyl)imino]pyrrolidine-1-carboxamide}zinc(II) (acetonitrile)trichloridozincate coordination complex By journals.iucr.org Published On :: 2024-01-01 The title complex, [ZnCl(C12H15N3O2)2][ZnCl3(CH3CN)], was synthesized and its structure was fully characterized through single-crystal X-ray diffraction analysis. The complex crystallizes in the orthorhombic system, space group Pbca (61), with a central zinc atom coordinating one chlorine atom and two pyrrolidinyl-4-methoxyphenyl azoformamide ligands in a bidentate manner, utilizing both the nitrogen and oxygen atoms in a 1,3-heterodiene (N=N—C=O) motif for coordinative bonding, yielding an overall positively (+1) charged complex. The complex is accompanied by a [(CH3CN)ZnCl3]− counter-ion. The crystal data show that the harder oxygen atoms in the heterodiene zinc chelate form bonding interactions with distances of 2.002 (3) and 2.012 (3) Å, while nitrogen atoms are coordinated by the central zinc cation with bond lengths of 2.207 (3) and 2.211 (3) Å. To gain further insight into the intermolecular interactions within the crystal, Hirshfeld surface analysis was performed, along with the calculation of two-dimensional fingerprint plots. This analysis revealed that H⋯H (39.9%), Cl⋯H/H⋯Cl (28.2%) and C⋯H/H⋯C (7.2%) interactions are dominant. This unique crystal structure sheds light on arrangement and bonding interactions with azoformamide ligands, and their unique qualities over similar semicarbazone and azothioformamide structures. Full Article text
m Crystal structure of dilithium biphenyl-4,4'-disulfonate dihydrate By journals.iucr.org Published On :: 2024-01-01 The asymmetric unit of the title compound, μ-biphenyl-4,4'-disulfonato-bis(aqualithium), [Li2(C12H8O6S2)(H2O)2] or Li2[Bph(SO3)2](H2O)2, consists of an Li ion, half of the diphenyl-4,4'-disulfonate [Bph(SO3−)2] ligand, and a water molecule. The Li ion exhibits a four-coordinate tetrahedral geometry with three oxygen atoms of the Bph(SO3−)2 ligands and a water molecule. The tetrahedral LiO4 units, which are interconnected by biphenyl moieties, form a layer structure parallel to (100). These layers are further connected by hydrogen-bonding interactions to yield a three-dimensional network. Full Article text
m Crystal structures of sixteen phosphane chalcogenide complexes of gold(I) chloride, bromide and iodide By journals.iucr.org Published On :: 2024-01-01 The structures of 16 phosphane chalcogenide complexes of gold(I) halides, with the general formula R13-nR2nPEAuX (R1 = t-butyl; R2 = isopropyl; n = 0 to 3; E = S or Se; X = Cl, Br or I), are presented. The eight possible chlorido derivatives are: 1a, n = 3, E = S; 2a, n = 2, E = S; 3a, n = 1, E = S; 4a, n = 0, E = S; 5a, n = 3, E = Se; 6a, n = 2, E = Se; 7a, n = 1, E = Se; and 8a, n = 0, E = Se, and the corresponding bromido derivatives are 1b–8b in the same order. However, 2a and 2b were badly disordered and 8a was not obtained. The iodido derivatives are 2c, 6c and 7c (numbered as for the series a and b). All structures are solvent-free and all have Z' = 1 except for 6b and 6c (Z' = 2). All molecules show the expected linear geometry at gold and approximately tetrahedral angles P—E—Au. The presence of bulky ligands forces some short intramolecular contacts, in particular H⋯Au and H⋯E. The Au—E bond lengths have a slight but consistent tendency to be longer when trans to a softer X ligand, and vice versa. The five compounds 1a, 5a, 6a, 1b and 5b form an isotypic set, despite the different alkyl groups in 6a. Compounds 3a/3b, 4b/8b and 6b/6c form isotypic pairs. The crystal packing can be analysed in terms of various types of secondary interactions, of which the most frequent are `weak' hydrogen bonds from methine hydrogen atoms to the halogenido ligands. For the structure type 1a, H⋯X and H⋯E contacts combine to form a layer structure. For 3a/3b, the packing is almost featureless, but can be described in terms of a double-layer structure involving borderline H⋯Cl/Br and H⋯S contacts. In 4a and 4b/8b, which lack methine groups, Cmethyl—H⋯X contacts combine to form layer structures. In 7a/7b, short C—H⋯X interactions form chains of molecules that are further linked by association of short Au⋯Se contacts to form a layer structure. The packing of compound 6b/6c can conveniently be analysed for each independent molecule separately, because they occupy different regions of the cell. Molecule 1 forms chains in which the molecules are linked by a Cmethine⋯Au contact. The molecules 2 associate via a short Se⋯Se contact and a short H⋯X contact to form a layer structure. The packing of compound 2c can be described in terms of two short Cmethine—H⋯I contacts, which combine to form a corrugated ribbon structure. Compound 7c is the only compound in this paper to feature Au⋯Au contacts, which lead to twofold-symmetric dimers. Apart from this, the packing is almost featureless, consisting of layers with only translation symmetry except for two very borderline Au⋯H contacts. Full Article text
m Crystal structure of a water oxidation catalyst solvate with composition (NH4)2[FeIV(L-6H)]·3CH3COOH (L = clathrochelate ligand) By journals.iucr.org Published On :: 2024-01-01 The synthetic availability of molecular water oxidation catalysts containing high-valent ions of 3d metals in the active site is a prerequisite to enabling photo- and electrochemical water splitting on a large scale. Herein, the synthesis and crystal structure of diammonium {μ-1,3,4,7,8,10,12,13,16,17,19,22-dodecaazatetracyclo[8.8.4.13,17.18,12]tetracosane-5,6,14,15,20,21-hexaonato}ferrate(IV) acetic acid trisolvate, (NH4)2[FeIV(C12H12N12O6)]·3CH3COOH or (NH4)2[FeIV(L–6H)]·3CH3COOH is reported. The FeIV ion is encapsulated by the macropolycyclic ligand, which can be described as a dodeca-aza-quadricyclic cage with two capping triazacyclohexane fragments making three five- and six six-membered alternating chelate rings with the central FeIV ion. The local coordination environment of FeIV is formed by six deprotonated hydrazide nitrogen atoms, which stabilize the unusual oxidation state. The FeIV ion lies on a twofold rotation axis (multiplicity 4, Wyckoff letter e) of the space group C2/c. Its coordination geometry is intermediate between a trigonal prism (distortion angle φ = 0°) and an antiprism (φ = 60°) with φ = 31.1°. The Fe—N bond lengths lie in the range 1.9376 (13)–1.9617 (13) Å, as expected for tetravalent iron. Structure analysis revealed that three acetic acid molecules additionally co-crystallize per one iron(IV) complex, and one of them is positionally disordered over four positions. In the crystal structure, the ammonium cations, complex dianions and acetic acid molecules are interconnected by an intricate system of hydrogen bonds, mainly via the oxamide oxygen atoms acting as acceptors. Full Article text
m Crystal structure of 2-[(5-amino-1-tosyl-1H-pyrazol-3-yl)oxy]-1-(4-methoxyphenyl)ethan-1-one 1,4-dioxane monosolvate By journals.iucr.org Published On :: 2024-01-01 In the structure of the title compound, C19H19N3O5S·C4H8O2, the two independent dioxane molecules each display inversion symmetry. The pyrazole ring is approximately parallel to the aromatic ring of the oxy-ethanone group and approximately perpendicular to the tolyl ring of the sulfonyl substituent. An extensive system of classical and `weak' hydrogen bonds connects the residues to form a layer structure parallel to (201), within which dimeric subunits are conspicuous; neighbouring layers are connected by classical hydrogen bonds to dioxanes and by `weak' hydrogen bonds from Htolyl donors. Full Article text
m When a dream comes true: birth of the African Crystallographic Association (AfCA) By journals.iucr.org Published On :: 2024-01-05 This paper summarizes brief perspectives on the historic process of establishing an African Crystallographic Association (AfCA) and includes representative references. It covers activities within four arbitrarily selected, approximate time slots, i.e., 1890s–1999, 2000–2013, 2014–2019 and 2020–2023. A genuine attempt is made to include appropriate role players, organizations and accompanying events within these periods. It concludes with the official admission of AfCA as the fifth Regional Associate of the IUCr at the 26th Congress and General Assembly of the IUCr in Melbourne, Australia in 2023. Full Article text
m Crystal structure and Hirshfeld-surface analysis of diaquabis(5-methyl-1H-1,2,4-triazole-3-carboxylato)copper(II) By journals.iucr.org Published On :: 2024-01-01 The title compound, [Cu(HL)2(H2O)2] or [Cu(C4H4N3O2)2(H2O)2], is a mononuclear octahedral CuII complex based on 5-methyl-1H-1,2,4-triazole-3-carboxylic acid (H2L). [Cu(HL)2(H2O)2] was synthesized by reaction of H2L with copper(II) nitrate hexahydrate (2:1 stoichiometric ratio) in water under ambient conditions to produce clear light-blue crystals. The central Cu atom exhibits an N2O4 coordination environment in an elongated octahedral geometry provided by two bidentate HL− anions in the equatorial plane and two water molecules in the axial positions. Hirshfeld surface analysis revealed that the most important contributions to the surface contacts are from H⋯O/O⋯H (33.1%), H⋯H (29.5%) and H⋯N/N⋯H (19.3%) interactions. Full Article text
m Synthesis, crystal structure and properties of poly[(μ-2-methylpyridine N-oxide-κ2O:O)bis(μ-thiocyanato-κ2N:S)cobalt(II)] By journals.iucr.org Published On :: 2024-01-01 The title compound, [Co(NCS)2(C6H7NO)]n or Co(NCS)2(2-methylpyridine N-oxide), was prepared by the reaction of Co(NCS)2 and 2-methylpyridine N-oxide in methanol. All crystals obtained by this procedure show reticular pseudo-merohedric twinning, but after recrystallization, one crystal was found that had a minor component with only a very few overlapping reflections. The asymmetric unit consists of one CoII cation, two thiocyanate anions and one 2-methylpyridine N-oxide coligand in general positions. The CoII cations are octahedrally coordinated by two O-bonding 2-methylpyridine N-oxide ligands, as well as two S- and two N-bonding thiocyanate anions, and are connected via μ-1,3(N,S)-bridging thiocyanate anions into chains that are linked by μ-1,1(O,O) bridging coligands into layers. No pronounced directional intermolecular interactions are observed between the layers. The 2-methylpyridine coligand is disordered over two orientations and was refined using a split model with restraints. Powder X-ray diffraction (PXRD) indicates that a pure sample was obtained and IR spectroscopy confirms that bridging thiocyanate anions are present. Thermogravimetry and differential thermoanalysis (TG-DTA) shows one poorly resolved mass loss in the TG curve that is accompanied by an exothermic and an endothermic signal in the DTA curve, which indicate the decomposition of the 2-methylpyridine N-oxide coligands. Full Article text
m Crystal structure and Hirshfeld surface analysis of dimethyl 4-hydroxy-5,4'-dimethyl-2'-(toluene-4-sulfonylamino)biphenyl-2,3-dicarboxylate By journals.iucr.org Published On :: 2024-01-01 In the title compound, C25H25NO7S, the molecular conformation is stabilized by intramolecular O—H⋯O and N—H⋯O hydrogen bonds, which form S(6) and S(8) ring motifs, respectively. The molecules are bent at the S atom with a C—SO2—NH—C torsion angle of −70.86 (11)°. In the crystal, molecules are linked by C—H⋯O and N—H⋯O hydrogen bonds, forming molecular layers parallel to the (100) plane. C—H⋯π interactions are observed between these layers. Full Article text
m Crystal structure and Hirshfeld surface analysis of 3-benzyl-2-[bis(1H-pyrrol-2-yl)methyl]thiophene By journals.iucr.org Published On :: 2024-01-01 In the title compound, C20H18N2S, the asymmetric unit comprises two similar molecules (A and B). In molecule A, the central thiophene ring makes dihedral angles of 89.96 (12) and 57.39 (13)° with the 1H-pyrrole rings, which are bent at 83.22 (14)° relative to each other, and makes an angle of 85.98 (11)° with the phenyl ring. In molecule B, the corresponding dihedral angles are 89.49 (13), 54.64 (12)°, 83.62 (14)° and 85.67 (11)°, respectively. In the crystal, molecular pairs are bonded to each other by N—H⋯N interactions. N—H⋯π and C—H⋯π interactions further connect the molecules, forming a three-dimensional network. A Hirshfeld surface analysis indicates that H⋯H (57.1% for molecule A; 57.3% for molecule B), C⋯H/H⋯C (30.7% for molecules A and B) and S⋯H/H⋯S (6.2% for molecule A; 6.4% for molecule B) interactions are the most important contributors to the crystal packing. Full Article text
m Crystal structure and Hirshfeld surface analysis of diethyl (3aS,3a1R,4S,5S,6R,6aS,7R,9aS)-3a1,5,6,6a-tetrahydro-1H,3H,4H,7H-3a,6:7,9a-diepoxybenzo[de]isochromene-4,5-dicarboxylate By journals.iucr.org Published On :: 2024-01-01 In the title compound, C18H22O7, two hexane rings and an oxane ring are fused together. The two hexane rings tend toward a distorted boat conformation, while the tetrahydrofuran and dihydrofuran rings adopt envelope conformations. The oxane ring is puckered. The crystal structure features C—H⋯O hydrogen bonds, which link the molecules into a three-dimensional network. According to a Hirshfeld surface study, H⋯H (60.3%) and O⋯H/H⋯O (35.3%) interactions are the most significant contributors to the crystal packing. Full Article text
m Temperature-dependent solid-state phase transition with twinning in the crystal structure of 4-methoxyanilinium chloride By journals.iucr.org Published On :: 2024-01-01 At room temperature, the title salt, C7H10NO+·Cl−, is orthorhombic, space group Pbca with Z' = 1, as previously reported [Zhao (2009). Acta Cryst. E65, o2378]. Between 250 and 200 K, there is a solid-state phase transition to a twinned monoclinic P21/c structure with Z' = 2. We report the high temperature structure at 250 K and the low-temperature structure at 100 K. In the low-temperature structure, the –NH3 hydrogen atoms are ordered and this group has a different orientation in each independent molecule, in keeping with optimizing N—H⋯Cl hydrogen bonding, some of which are bifurcated: these hydrogen bonds have N⋯Cl distances in the range 3.1201 (8)–3.4047 (8) Å. In the single cation of the high-temperature structure, the NH hydrogen atoms are disordered into the average of the two low-temperature positions and the N⋯Cl hydrogen bond distances are in the range 3.1570 (15)–3.3323 (18) Å. At both temperatures, the methoxy group is nearly coplanar with the rest of the molecule, with the C—C—O—C torsion angles being −7.0 (2)° at 250 K and −6.94 (12) and −9.35 (12)° at 100 K. In the extended orthorhombic structure, (001) hydrogen-bonded sheets occur; in the monoclinic structure, the sheets propagate in the (010) plane. Full Article text
m Crystal structures of two formamidinium hexafluoridophosphate salts, one with batch-dependent disorder By journals.iucr.org Published On :: 2024-01-01 Syntheses of the acyclic amidinium salts, morpholinoformamidinium hexafluoridophosphate [OC4H8N—CH=NH2]PF6 or C5H11N2O+·PF6−, 1, and pyrrolidinoformamidinium hexafluoridophosphate [C4H8N—CH= NH2]PF6 or C5H11N2+·PF6−, 2, were carried out by heating either morpholine or pyrrolidine with triethyl orthoformate and ammonium hexafluoridophosphate. Crystals of 1 obtained directly from the reaction mixture contain one cation and one anion in the asymmetric unit. The structure involves cations linked in chains parallel to the b axis by N—H⋯O hydrogen bonds in space group Pbca, with glide-related chains pointing in opposite directions. Crystals of 1 obtained by recrystallization from ethanol, however, showed a similar unit cell and the same basic structure, but unexpectedly, there was positional disorder [occupancy ratio 0.639 (4):0.361 (4)] in one of the cation chains, which lowered the crystal symmetry to the non-centrosymmetric space group Pca21, with two cations and anions in the asymmetric unit. In the pyrrolidino compound, 2, cations and anions are ordered and are stacked separately, with zigzag N—H⋯F hydrogen-bonding between stacks, forming ribbons parallel to (101), extended along the b-axis direction. Slight differences in the delocalized C=N distances between the two cations may reflect the inductive effect of the oxygen atom in the morpholino compound. Full Article text
m Crystal structure and Hirshfeld surface analysis of 2-picolyllithium·3thf By journals.iucr.org Published On :: 2024-01-01 In the title compound, (2-methylidene-1,2-dihydropyridinium-κN)tris(tetrahydrofuran-κO)lithium, [Li(C6H6N)(C4H8O)3], the lithium ion adopts a distorted LiNO3 tetrahedral coordination geometry and the 2-picolyl anion adopts its enamido form with the lithium ion lying close to the plane of the pyridine ring. A methylene group of one of the thf ligands is disordered over two orientations. In the crystal, a weak C—H⋯O interaction generates inversion dimers. A Hirshfeld surface analysis shows that H⋯H contacts dominate the packing (86%) followed by O⋯H/H⋯O and C⋯H/H⋯C contacts, which contribute 3% and 10.4%, respectively. Full Article text
m JUAMI, the joint undertaking for an African materials institute: building materials science research collaborations and capabilities between continents By journals.iucr.org Published On :: 2024-01-26 JUAMI, the joint undertaking for an African materials institute, is a project to build collaborations and materials research capabilities between PhD researchers in Africa, the United States, and the world. Focusing on research-active universities in the East African countries of Kenya, Ethiopia, Tanzania and Uganda, the effort has run a series of schools focused on materials for sustainable energy and materials for sustainable development. These bring together early-career researchers from Africa, the US, and beyond, for two weeks in a close-knit environment. The program includes lectures on cutting-edge research from internationally renowned speakers, highly interactive tutorial lectures on the science behind the research, also from internationally known researchers, and hands-on practicals and team-building exercises that culminate in group proposals from self-formed student teams. The schools have benefited more than 300 early-career students and led to proposals that have received funding and have led to research collaborations and educational non-profits. JUAMI continues and has an ongoing community of alumni who share resources and expertise, and is open to like-minded people who want to join and develop contacts and collaborations internationally. Full Article text
m Crystal structure of poly[hexa-μ-bromido-bis{2-[1-(pyridin-2-yl)ethylideneamino]ethanolato}tetracopper(II)] By journals.iucr.org Published On :: 2024-01-12 The reaction of the Schiff base 2-[1-(pyridin-2-yl)ethylideneamino]ethanol (HL), which is formed by reaction of 2-aminoethanol and 2-acetylpyridine with CuBr2 in ethanol results in the isolation of the new polymeric complex poly[hexa-μ-bromido-bis{2-[1-(pyridin-2-yl)ethylideneamino]ethanolato}tetracopper(II)], [Cu4Br6(C9H11N2O)2]n or [Cu4Br6L2]n. The asymmetric unit of the crystal structure of the polymeric [Cu4Br6L2]n complex is composed by four copper (II) cations, two monodeprotonated molecules of the ligand, and six bromide anions, which act as bridges. The ligand molecules act in a tridentate fashion through their azomethine nitrogen atoms, their pyridine nitrogen atoms, and their alcoholate O atoms. The crystal structure shows two types of geometries in the coordination polyhedrons around Cu2+ ions. Two copper cations are situated in a square-based pyramidal environment, while the two other copper cations adopt a tetrahedral geometry. Bromides anions acting as bridges between two metal ions connect the units, resulting in a tetranuclear polymer compound. Full Article text
m Synthesis, structure and Hirshfeld surface analysis of 2-oxo-2H-chromen-6-yl 4-tert-butylbenzoate: work carried out as part of the AFRAMED project By journals.iucr.org Published On :: 2024-01-05 In the title compound, C20H18O4, the dihedral angle between the 2H-chromen-2-one ring system and the phenyl ring is 89.12 (5)°. In the crystal, the molecules are connected through C—H⋯O hydrogen bonds to generate [010] double chains that are reinforced by weak aromatic π–π stacking interactions. The unit-cell packing can be described as a tilted herringbone motif. The H⋯H, H⋯O/O⋯H, H⋯C/C⋯H and C⋯C contacts contribute 46.7, 24.2, 16.7 and 7.6%, respectively, to its Hirshfeld surface. Full Article text
m An unexpected tautomer: synthesis and crystal structure of N-[6-amino-4-(methylsulfanyl)-1,2-dihydro-1,3,5-triazin-2-ylidene]benzenesulfonamide By journals.iucr.org Published On :: 2024-01-09 The title compound, C10H11N5O2S2, consists of an unexpected tautomer with a protonated nitrogen atom in the triazine ring and a formal exocyclic double bond C=N to the sulfonamide moiety. The ring angles at the unsubstituted nitrogen atoms are narrow, at 115.57 (12) and 115.19 (12)°, respectively, whereas the angle at the carbon atom between these N atoms is very wide, 127.97 (13)°. The interplanar angle between the two rings is 79.56 (5)°. The molecules are linked by three classical hydrogen bonds, forming a ribbon structure. There are also unusual linkages involving three short contacts (< 3 Å) from a sulfonamide oxygen atom to the C—NH—C part of a triazine ring. Full Article text
m Crystal structure of a layered phosphate molybdate K2Gd(PO4)(MoO4) By journals.iucr.org Published On :: 2024-01-05 The title compound dipotassium gadolinium(III) phosphate(V) molybdate(VI), K2Gd(PO4)(MoO4), was synthesized from a high-temperature melt starting from GdF3 as a source of gadolinium. Its structure is isotypic with other MI2MIII(MVIO4)(PO4) compounds, where MI = Na, K or Cs, and MIII = rare-earth cation, MVI = Mo or W. The three-dimensional framework is built up from [Gd(PO4)(MoO4)] anionic sheets, which are organized by adhesion of [GdPO4] layers and [MoO4] tetrahedra stacked above and below these layers. The interstitial space is occupied by K cations having eightfold oxygen coordination. The polyhedron of GdO8 was estimated to be a triangular dodecahedron by the continuous shape measurement method. Full Article text
m Crystal structure and Hirshfeld surface analysis of (E)-2-[2-(2-amino-1-cyano-2-oxoethylidene)hydrazin-1-yl]benzoic acid N,N-dimethylformamide monosolvate By journals.iucr.org Published On :: 2024-01-05 In the title compound, C10H8N4O3·C3H7NO, the asymmetric unit contains two crystallographically independent molecules A and B, each of which has one DMF solvate molecule. Molecules A and B both feature intramolecular N—H⋯O hydrogen bonds, forming S(6) ring motifs and consolidating the molecular configuration. In the crystal, N—H⋯O and O—H⋯O hydrogen bonds connect molecules A and B, forming R22(8) ring motifs. Weak C—H⋯O interactions link the molecules, forming layers parallel to the (overline{2}12) plane. The DMF solvent molecules are also connected to the main molecules (A and B) by N—H⋯O hydrogen bonds. π–π stacking interactions [centroid-to-centroid distance = 3.8702 (17) Å] between the layers also increase the stability of the molecular structure in the third dimension. According to the Hirshfeld surface study, O⋯H/H⋯O interactions are the most significant contributors to the crystal packing (27.5% for molecule A and 25.1% for molecule B). Full Article text
m {[(E)-(1,3-Benzodioxol-5-yl)methylidene]amino}thiourea By journals.iucr.org Published On :: 2024-01-09 The synthesis and crystallographic analysis of the title compound, C9H9N3O2S, are reported. The compound crystallizes in the monoclinic space group P21/c, revealing characteristic bond lengths and angles typical of thiosemicarbazone groups. The supramolecular organization primarily arises from hydrogen bonding and π–π stacking interactions, leading to distinctive dimeric formations. Full Article text
m Synthesis and crystal structure of a cadmium(II) coordination polymer based on 4,4'-(1H-1,2,4-triazole-3,5-diyl)dibenzoate By journals.iucr.org Published On :: 2024-01-09 The asymmetric unit of the title compound, catena-poly[[[aquabis(pyridine-κN)cadmium(II)]-μ2-4,4'-(1H-1,2,4-triazole-3,5-diyl)dibenzoato-κ4O,O':O'',O'''] 4.5-hydrate], {[Cd(C16H9N3O4)(C5H5N)2(H2O)]·4.5H2O}n or {[Cd(bct)(py)2(H2O)]·4.5H2O}n (I), consists of a Cd2+ cation coordinated to one bct2– carboxylate dianion, two molecules of pyridine and a water molecule as well as four and a half water molecules of crystallization. The metal ion in I possesses a pentagonal–bipyramidal environment with the four O atoms of the two bidentately coordinated carboxylate groups and the N atom of a pyridine molecule forming the O4N equatorial plane, while the N atom of another pyridine ligand and the O atom of the water molecule occupy the axial positions. The bct2– bridging ligand connects two metal ions via its carboxylic groups, resulting in the formation of a parallel linear polymeric chain running along the [1overline{1}1] direction. The coordinated water molecule of one chain forms a strong O—H⋯O hydrogen bond with the carboxylate O atom of a neighboring chain, leading to the formation of double chains with a closest distance of 5.425 (7) Å between the cadmium ions belonging to different chains. Aromatic π–π stacking interactions between the benzene fragments of the anions as well as between the coordinated pyridine molecules belonging to different chains results in the formation of sheets oriented parallel to the (overline{1}01) plane. As a result of hydrogen-bonding interactions involving the water molecules of crystallization, the sheets are joined together in a three-dimensional network. Full Article text