ph Synthesis, crystal structure and thermal properties of a new polymorphic modification of diisothiocyanatotetrakis(4-methylpyridine)cobalt(II) By journals.iucr.org Published On :: 2024-05-31 The title compound, [Co(NCS)2(C6H7N)4] or Co(NCS)2(4-methylpyridine)4, was prepared by the reaction of Co(NCS)2 with 4-methylpyridine in water and is isotypic to one of the polymorphs of Ni(NCS)2(4-methylpyridine)4 [Kerr & Williams (1977). Acta Cryst. B33, 3589–3592 and Soldatov et al. (2004). Cryst. Growth Des. 4, 1185–1194]. Comparison of the experimental X-ray powder pattern with that calculated from the single-crystal data proves that a pure phase has been obtained. The asymmetric unit consists of one CoII cation, two crystallographically independent thiocyanate anions and four independent 4-methylpyridine ligands, all located in general positions. The CoII cations are sixfold coordinated to two terminally N-bonded thiocyanate anions and four 4-methylpyridine coligands within slightly distorted octahedra. Between the complexes, a number of weak C—H⋯N and C—H⋯S contacts are found. This structure represent a polymorphic modification of Co(NCS)2(4-methylpyridine)4 already reported in the CCD [Harris et al. (2003). NASA Technical Reports, 211890]. In contrast to this form, the crystal structure of the new polymorph shows a denser packing, indicating that it is thermodynamically stable at least at low temperatures. Thermogravimetric and differential thermoanalysis reveal that the title compound starts to decomposes at about 100°C and that the coligands are removed in separate steps without any sign of a polymorphic transition before decomposition. Full Article text
ph Synthesis and crystal structures of two racemic 2-heteroaryl-3-phenyl-2,3-dihydro-4H-pyrido[3,2-e][1,3]thiazin-4-ones By journals.iucr.org Published On :: 2024-06-04 3-Phenyl-2-(thiophen-3-yl)-2,3-dihydro-4H-pyrido[3,2-e][1,3]thiazin-4-one (C17H12N2OS2, 1) and 2-(1H-indol-3-yl)-3-phenyl-2,3-dihydro-4H-pyrido[3,2-e][1,3]thiazin-4-one 0.438-hydrate (C21H15N3OS·0.438H2O, 2) crystallize in space groups P21/n and C2/c, respectively. The asymmetric unit in each case is comprised of two parent molecules, albeit of mixed chirality in the case of 1 and of similar chirality in 2 with the enantiomers occupying the neighboring asymmetric units. Structure 2 also has water molecules (partial occupancies) that form continuous channels along the b-axis direction. The thiazine rings in both structures exhibit an envelope conformation. Intermolecular interactions in 1 are defined only by C—H⋯O and C—H⋯N hydrogen bonds between crystallographically independent molecules. In 2, hydrogen bonds of the type N—H⋯O between independent molecules and C—H⋯N(π) type, and π–π stacking interactions between the pyridine rings of symmetry-related molecules are observed. Full Article text
ph A 1:1 flavone cocrystal with cyclic trimeric perfluoro-o-phenylenemercury By journals.iucr.org Published On :: 2024-06-14 The title compound, systematic name tris(μ2-perfluoro-o-phenylene)(μ2-3-phenyl-4H-chromen-4-one)-triangulo-trimercury, [Hg3(C6F4)3(C15H10O2)], crystallizes in the monoclinic P21/n space group with one flavone (FLA) and one cyclic trimeric perfluoro-o-phenylenemercury (TPPM) molecule per asymmetric unit. The FLA molecule is located on one face of the TPPM acceptor and is linked in an asymmetric coordination of its carbonyl oxygen atom with two Hg centers of the TPPM macrocycle. The angular-shaped complexes pack in zigzag chains where they stack via two alternating TPPM–TPPM and FLA–FLA stacking patterns. The distance between the mean planes of the neighboring TPPM macrocycles in the stack is 3.445 (2) Å, and that between the benzo-γ-pyrone moieties of FLA is 3.328 (2) Å. The neighboring stacks are interdigitated through the shortened F⋯F, CH⋯F and CH⋯π contacts, forming a dense crystal structure. Full Article text
ph Crystal structure of tris{N,N-diethyl-N'-[(4-nitrophenyl)(oxo)methyl]carbamimidothioato}cobalt(III) By journals.iucr.org Published On :: 2024-06-11 The synthesis, crystal structure, and a Hirshfeld surface analysis of tris{N,N-diethyl-N'-[(4-nitrophenyl)(oxo)methyl]carbamimidothioato}cobalt(III) conducted at 180 K are presented. The complex consists of three N,N-diethyl-N'-[(4-nitrobenzene)(oxo)methyl]carbamimidothioato ligands, threefold symmetrically bonded about the CoIII ion, in approximately octahedral coordination, which generates a triple of individually near planar metallacyclic (Co—S—C—N—C—O) rings. The overall geometry of the complex is determined by the mutual orientation of each metallacycle about the crystallographically imposed threefold axis [dihedral angles = 81.70 (2)°] and by the dihedral angles between the various planar groups within each asymmetric unit [metallacycle to benzene ring = 13.83 (7)°; benzene ring to nitro group = 17.494 (8)°]. The complexes stack in anti-parallel columns about the overline{3} axis of the space group (Poverline{3}), generating solvent-accessible channels along [001]. These channels contain ill-defined, multiply disordered, partial-occupancy solvent. Atom–atom contacts in the crystal packing predominantly (∼96%) involve hydrogen, the most abundant types being H⋯H (36.6%), H⋯O (31.0%), H⋯C (19.2%), H⋯N (4.8%), and H⋯S (4.4%). Full Article text
ph Crystal structure of hexachlorothallate within a caesium chloride–phosphotungstate lattice Cs9(TlCl6)(PW12O40)2·9CsCl By journals.iucr.org Published On :: 2024-06-14 Crystal formation of caesium thallium chloride phosphotungstates, Cs9(TlCl6)(PW12O40)2·9CsCl showcases the ability to capture and crystallize octahedral complexes via the use of polyoxometalates (POMs). The large number of caesium chlorides allows for the POM [α-PW12O40]3− to arrange itself in a cubic close-packing lattice extended framework, in which the voids created enable the capture of the [TlCl6]3− complex. Full Article text
ph Synthesis, spectroscopic analysis and crystal structure of (N-{2-[(2-aminoethyl)amino]ethyl}-4'-methyl-[1,1'-biphenyl]-4-sulfonamidato)tricarbonylrhenium(I) By journals.iucr.org Published On :: 2024-06-18 The title compound, [Re(C17H22N3O2S)(CO)3] is a net neutral fac-Re(I)(CO)3 complex of the 4-methylbiphenyl sulfonamide derivatized diethylenetriamine ligand. The NNN-donor monoanionic ligand coordinates with the Re core in tridentate fashion, establishing an inner coordination sphere resulting in a net neutral complex. The complex possesses pseudo-octahedral geometry where one face of the octahedron is occupied by three carbonyl ligands and the other faces are occupied by one sp2 nitrogen atom of the sulfonamide group and two sp3 nitrogen atoms of the dien backbone. The Re—Nsp2 bond distance, 2.173 (4) Å, is shorter than the Re—Nsp3 bond distances, 2.217 (5) and 2.228 (6) Å, and is similar to the range reported for typical Re—Nsp2 bond lengths (2.14 to 2.18 Å). Full Article text
ph Crystal structure and Hirshfeld surface analysis of dimethyl(phenyl)phosphine sulfide By journals.iucr.org Published On :: 2024-06-18 The title compound, C8H11PS, which melts below room temperature, was crystallized at low temperature. The P—S bond length is 1.9623 (5) Å and the major contributors to the Hirshfeld surface are H⋯H (58.1%), S⋯H/H⋯S (13.4%) and C⋯H/H⋯C contacts (11.7%). Full Article text
ph Crystal structure of tricarbonyl[η4-6-exo-(triphenylphosphino)cyclohepta-2,4-dien-1-one]iron(0) tetrafluoroborate By journals.iucr.org Published On :: 2024-06-18 The molecular structure of tricarbonyl[η4-6-exo-(triphenylphosphino)cyclohepta-2,4-dien-1-one]iron(0) tetrafluoroborate dichloromethane hemisolvate, [Fe(C28H22O4)(CO)3]BF4·0.5CH2Cl2, as determined by single-crystal X-ray diffraction is reported. The two independent tricarbonyl[η4-6-exo-(triphenylphosphino)cyclohepta-2,4-dien-1-one] iron(0) cations and their corresponding anions form dimers, which constitute the asymmetric unit of the structure parallel to the (100) plane. Solid-state stability within that asymmetric unit as well as between neighboring dimeric units is afforded by C—H⋯O and C—H⋯F hydrogen bonds and C—H⋯π and Y—X⋯π (Y = B, C; X = F, O) interactions, which yield diperiodic sheets and a three-dimensional extended network. Full Article text
ph Crystal structure and Hirshfeld surface analysis of 1-[6-bromo-2-(4-fluorophenyl)-1,2,3,4-tetrahydroquinolin-4-yl]pyrrolidin-2-one By journals.iucr.org Published On :: 2024-06-25 In the title compound, C19H18BrFN2O, the pyrrolidine ring adopts an envelope conformation. In the crystal, molecules are linked by intermolecular N—H⋯O, C—H⋯O, C—H⋯F and C—H⋯Br hydrogen bonds, forming a three-dimensional network. In addition, C—H⋯π interactions connect molecules into ribbons along the b-axis direction, consolidating the molecular packing. The intermolecular interactions in the crystal structure were quantified and analysed using Hirshfeld surface analysis. Full Article text
ph Synthesis, crystal structure and photophysical properties of a dinuclear MnII complex with 6-(diethylamino)-4-phenyl-2-(pyridin-2-yl)quinoline By journals.iucr.org Published On :: 2024-06-28 A new quinoline derivative, namely, 6-(diethylamino)-4-phenyl-2-(pyridin-2-yl)quinoline, C24H23N3 (QP), and its MnII complex aqua-1κO-di-μ-chlorido-1:2κ4Cl:Cl-dichlorido-1κCl,2κCl-bis[6-(diethylamino)-4-phenyl-2-(pyridin-2-yl)quinoline]-1κ2N1,N2;2κ2N1,N2-dimanganese(II), [Mn2Cl4(C24H23N3)2(H2O)] (MnQP), were synthesized. Their compositions have been determined with ESI-MS, IR, and 1H NMR spectroscopy. The crystal-structure determination of MnQP revealed a dinuclear complex with a central four-membered Mn2Cl2 ring. Both MnII atoms bind to an additional Cl atom and to two N atoms of the QP ligand. One MnII atom expands its coordination sphere with an extra water molecule, resulting in a distorted octahedral shape. The second MnII atom shows a distorted trigonal–bipyramidal shape. The UV–vis absorption and emission spectra of the examined compounds were studied. Furthermore, when investigating the aggregation-induced emission (AIE) properties, it was found that the fluorescent color changes from blue to green and eventually becomes yellow as the fraction of water in the THF/water mixture increases from 0% to 99%. In particular, these color and intensity changes are most pronounced at a water fraction of 60%. The crystal structure contains disordered solvent molecules, which could not be modeled. The SQUEEZE procedure [Spek (2015). Acta Cryst. C71, 9–18] was used to obtain information on the type and quantity of solvent molecules, which resulted in 44 electrons in a void volume of 274 Å3, corresponding to approximately 1.7 molecules of ethanol in the unit cell. These ethanol molecules are not considered in the given chemical formula and other crystal data. Full Article text
ph A monoclinic polymorph of chlorothiazide By journals.iucr.org Published On :: 2024-06-28 A new polymorph of the diuretic chlorothiazide, 6-chloro-1,1-dioxo-2H-1,2,4-benzothiazine-7-sulfonamide, C7H6ClN3O4S2, is described. Crystallized from basic aqueous solution, this monoclinic polymorph is found to be less thermodynamically favoured than the known triclinic polymorph and to feature only N—H⋯O type intermolecular hydrogen bonds as opposed to the N—H⋯O and N—H⋯N type hydrogen bonds found in the P1 form. Full Article text
ph Synthesis, structural studies and Hirshfeld surface analysis of 2-[(4-phenyl-1H-1,2,3-triazol-1-yl)methyl]pyridin-1-ium hexakis(nitrato-κ2O,O')thorate(IV) By journals.iucr.org Published On :: 2024-07-05 Reaction of thorium(IV) nitrate with 2-[(4-phenyl-1H-1,2,3-triazol-1-yl)methyl]pyridine (L) yielded (LH)2[Th(NO3)6] or (C14H13N4)2[Th(NO3)6] (1), instead of the expected mixed-ligand complex [Th(NO3)4L2], which was detected in the mass spectrum of 1. In the structure, the [Th(NO3)6]2− anions display an icosahedral coordination geometry and are connected by LH+ cations through C—H⋯O hydrogen bonds. The LH+ cations interact via N—H⋯N hydrogen bonds. Hirshfeld surface analysis indicates that the most important interactions are O⋯H/H⋯O hydrogen-bonding interactions, which represent a 55.2% contribution. Full Article text
ph Crystal structure of catena-poly[[methanoldioxidouranium(VI)]-μ-2-[5-(2-oxidophenyl)-1H-1,2,4-triazol-3-yl]acetato-κ2O:O'] By journals.iucr.org Published On :: 2024-07-12 In the title complex, [U(C10H7N3O3)O2(CH3OH)]n, the UVI cation has a typical pentagonal–bipyramidal environment with the equatorial plane defined by one N and two O atoms of one doubly deprotonated 2-[5-(2-hydroxyphenyl)-1H-1,2,4-triazol-3-yl]acetic acid ligand, a carboxylate O atom of the symmetry-related ligand and the O atom of the methanol molecule [U—N/Oeq 2.256 (4)–2.504 (5) Å]. The axial positions are occupied by two oxide O atoms. The equatorial atoms are almost coplanar, with the largest deviation from the mean plane being 0.121 Å for one of the O atoms. The benzene and triazole rings of the tetradentate chelating–bridging ligand are twisted by approximately 21.6 (2)° with respect to each other. The carboxylate group of the ligand bridges two uranyl cations, forming a neutral zigzag chain reinforced by a strong O—H⋯O hydrogen bond. In the crystal, adjacent chains are linked into two-dimensional sheets parallel to the ac plane by C/N—H⋯N/O hydrogen bonding and π–π interactions. Further weak C—H⋯O contacts consolidate the three-dimensional supramolecular architecture. In the solid state, the compound shows a broad medium intensity LMCT transition centred around 463 nm, which is responsible for its red colour. Full Article text
ph Crystal structure determination and Hirshfeld surface analysis of N-acetyl-N-3-methoxyphenyl and N-(2,5-dimethoxyphenyl)-N-phenylsulfonyl derivatives of N-[1-(phenylsulfonyl)-1H-indol-2-yl]methanamine By journals.iucr.org Published On :: 2024-07-09 Two new [1-(phenylsulfonyl)-1H-indol-2-yl]methanamine derivatives, namely, N-(3-methoxyphenyl)-N-{[1-(phenylsulfonyl)-1H-indol-2-yl]methyl}acetamide, C24H22N2O4S, (I), and N-(2,5-dimethoxyphenyl)-N-{[1-(phenylsulfonyl)-1H-indol-2-yl]methyl}benzenesulfonamide, C29H26N2O6S2, (II), reveal a nearly orthogonal orientation of their indole ring systems and sulfonyl-bound phenyl rings. The sulfonyl moieties adopt the anti-periplanar conformation. For both compounds, the crystal packing is dominated by C—H⋯O bonding [C⋯O = 3.312 (4)–3.788 (8) Å], with the structure of II exhibiting a larger number, but weaker bonds of this type. Slipped π–π interactions of antiparallel indole systems are specific for I, whereas the structure of II delivers two kinds of C—H⋯π interactions at both axial sides of the indole moiety. These findings agree with the results of Hirshfeld surface analysis. The primary contributions to the surface areas are associated with the contacts involving H atoms. Although II manifests a larger fraction of the O⋯H/H⋯O contacts (25.8 versus 22.4%), most of them are relatively distal and agree with the corresponding van der Waals separations. Full Article text
ph Crystal and molecular structure of 2-methyl-1,4-phenylene bis(3,5-dibromobenzoate) By journals.iucr.org Published On :: 2024-07-15 The aryl diester compound, 2-methyl-1,4-phenylene bis(3,5-dibromobenzoate), C21H12Br4O4, was synthesized by esterification of methyl hydroquinone with 3,5-dibromobenzoic acid. A crystalline sample was obtained by cooling a sample of the melt (m.p. = 502 K/DSC) to room temperature. The molecular structure consists of a central benzene ring with anti-3,5-dibromobenzoate groups symmetrically attached at the 1 and 4 positions and a methyl group attached at the 2 position of the central ring. In the crystal structure (space group Poverline{1}), molecules of the title aryl diester are located on inversion centers imposing disorder of the methyl group and H atom across the central benzene ring. The crystal structure is consolidated by a network of C—H⋯Br hydrogen bonds in addition to weaker and offset π–π interactions involving the central benzene rings as well as the rings of the attached 3,5-dibromobenzoate groups. Full Article text
ph Synthesis, crystal structure and Hirshfeld surface of ethyl 2-[2-(methylsulfanyl)-5-oxo-4,4-diphenyl-4,5-dihydro-1H-imidazol-1-yl]acetate (thiophenytoin derivative) By journals.iucr.org Published On :: 2024-08-09 The dihydroimidazole ring in the title molecule, C20H20N2O3S, is slightly distorted and the lone pair on the tri-coordinate nitrogen atom is involved in intra-ring π bonding. The methylsulfanyl substituent lies nearly in the plane of the five-membered ring while the ester substituent is rotated well out of that plane. In the crystal, C—H⋯O hydrogen bonds form inversion dimers, which are connected along the a- and c-axis directions by additional C—H⋯O hydrogen bonds, forming layers parallel to the ac plane. The major contributors to the Hirshfeld surface are C⋯H/H⋯C, O⋯H/H⋯O and S⋯H/H⋯S contacts at 20.5%, 14.7% and 4.9%, respectively. Full Article text
ph Synthesis, crystal structure and Hirshfeld surface analysis of [1-(4-bromophenyl)-1H-1,2,3-triazol-4-yl]methyl 2-(4-nitrophenoxy)acetate By journals.iucr.org Published On :: 2024-07-31 The title compound, C17H13BrN4O5, was synthesized by a Cu2Br2-catalysed Meldal–Sharpless reaction between 4-nitrophenoxyacetic acid propargyl ether and para-bromophenylazide, and characterized by X-ray structure determination and 1H NMR spectroscopy. The molecules, with a near-perpendicular orientation of the bromophenyl-triazole and nitrophenoxyacetate fragments, are connected into a three-dimensional network by intermolecular C—H⋯O and C—H⋯N hydrogen bonds (confirmed by Hirshfeld surface analysis), π–π and Br–π interactions. Full Article text
ph Synthesis and crystal structure of (2E)-1-[3,5-bis(benzyloxy)phenyl]-3-(4-ethoxyphenyl)prop-2-en-1-one By journals.iucr.org Published On :: 2024-08-06 In the title compound, C31H28O4, the phenyl rings of the chalcone unit subtend a dihedral angle of 26.43 (10)°. The phenyl rings of the pendant benzyloxy groups are orientated at 75.57 (13) and 75.70 (10)° with respect to their attached ring. In the crystal, weak C—H⋯O and C—H⋯π interactions link the molecules. The intermolecular interactions were quantified and analysed using Hirshfeld surface analysis, which showed a breakdown into H⋯H (49.8%), H⋯C/C⋯H (33.8%) and H⋯O/O⋯H (13.6%) interactions with other types making negligible contributions. Full Article text
ph Synthesis, crystal structure and Hirshfeld surface analysis of 1-[(1-octyl-1H-1,2,3-triazol-4-yl)methyl]-3-phenyl-1,2-dihydroquinoxalin-2(1H)-one By journals.iucr.org Published On :: 2024-08-09 In the title molecule, C25H29N5O, the dihydroquinoxaline unit is not quite planar (r.m.s. deviation = 0.030 Å) as there is a dihedral angle of 2.69 (3)° between the mean planes of the constituent rings and the molecule adopts a hairpin conformation. In the crystal, the polar portions of the molecules are associated through C—H⋯O and C—H⋯N hydrogen bonds and C—H⋯π(ring) and C=O⋯π(ring) interactions, forming thick layers parallel to the bc plane and with the n-octyl groups on the outside surfaces. Full Article text
ph Crystal structure of (1,4,7,10,13,16-hexaoxacyclooctadecane-κ6O)potassium-μ-oxalato-triphenylstannate(IV), the first reported 18-crown-6-stabilized potassium salt of triphenyloxalatostannate By journals.iucr.org Published On :: 2024-08-13 The title complex, (1,4,7,10,13,16-hexaoxacyclooctadecane-1κ6O)(μ-oxalato-1κ2O1,O2:2κ2O1',O2')triphenyl-2κ3C-potassium(I)tin(IV), [KSn(C6H5)3(C2O4)(C12H24O6)] or K[18-Crown-6][(C6H5)3SnO4C2], was synthesized. The complex consists of a potassium cation coordinated to the six oxygen atoms of a crown ether molecule and the two oxygen atoms of the oxalatotriphenylstannate anion. It crystallizes in the monoclinic crystal system within the space group P21. The tin atom is coordinated by one chelating oxalate ligand and three phenyl groups, forming a cis-trigonal–bipyramidal geometry around the tin atom. The cations and anions form ion pairs, linked through carbonyl coordination to the potassium atoms. The crystal structure features C—H⋯O hydrogen bonds between the oxygen atoms of the oxalate group and the hydrogen atoms of the phenyl groups, resulting in an infinite chain structure extending along a-axis direction. The primary inter-chain interactions are van der Waals forces. Full Article text
ph Crystal structure and Hirshfeld surface analysis of 1-[6-bromo-2-(3-bromophenyl)-1,2,3,4-tetrahydroquinolin-4-yl]pyrrolidin-2-one By journals.iucr.org Published On :: 2024-08-30 This study presents the synthesis, characterization and Hirshfeld surface analysis of 1-[6-bromo-2-(3-bromophenyl)-1,2,3,4-tetrahydroquinolin-4-yl]pyrrolidin-2-one, C19H18Br2N2O. In the title compound, the pyrrolidine ring adopts a distorted envelope configuration. In the crystal, molecules are linked by intermolecular N—H⋯O, C—H⋯O and C—H⋯Br hydrogen bonds, forming a three-dimensional network. In addition, pairs of molecules along the c axis are connected by C—H⋯π interactions. According to a Hirshfeld surface study, H⋯H (36.9%), Br⋯H/H⋯Br (28.2%) and C⋯H/H⋯C (24.3%) interactions are the most significant contributors to the crystal packing. Full Article text
ph Crystal structure, Hirshfeld surface analysis, DFT and the molecular docking studies of 3-(2-chloroacetyl)-2,4,6,8-tetraphenyl-3,7-diazabicyclo[3.3.1]nonan-9-one By journals.iucr.org Published On :: 2024-08-30 In the title compound, C33H29ClN2O2, the two piperidine rings of the diazabicyclo moiety adopt distorted-chair conformations. Intermolecular C—H⋯π interactions are mainly responsible for the crystal packing. The intermolecular interactions were quantified and analysed using Hirshfeld surface analysis, revealing that H⋯H interactions contribute most to the crystal packing (52.3%). The molecular structure was further optimized by density functional theory (DFT) at the B3LYP/6–31 G(d,p) level and is compared with the experimentally determined molecular structure in the solid state. Full Article text
ph Crystal structure of a tris(2-aminoethyl)methane capped carbamoylmethylphosphine oxide compound By journals.iucr.org Published On :: 2024-08-30 The molecular structure of the tripodal carbamoylmethylphosphine oxide compound diethyl {[(5-[2-(diethoxyphosphoryl)acetamido]-3-{2-[2-(diethoxyphosphoryl)acetamido]ethyl}pentyl)carbamoyl]methyl}phosphonate, C25H52N3O12P3, features six intramolecular hydrogen-bonding interactions. The phosphonate groups have key bond lengths ranging from 1.4696 (12) to 1.4729 (12) Å (P=O), 1.5681 (11) to 1.5811 (12) Å (P—O) and 1.7881 (16) to 1.7936 (16) Å (P—C). Each amide group adopts a nearly perfect trans geometry, and the geometry around each phophorus atom resembles a slightly distorted tetrahedron. Full Article text
ph Crystal structure, Hirshfeld surface analysis, DFT optimized molecular structure and the molecular docking studies of 1-[2-(cyanosulfanyl)acetyl]-3-methyl-2,6-bis(4-methylphenyl)piperidin-4-one By journals.iucr.org Published On :: 2024-09-12 The two molecules in the asymmetric unit of the title compound, C23H24N2O2S, have a structural overlap with an r.m.s. deviation of 0.82 Å. The piperidine rings adopt a distorted boat conformation. Intra- and intermolecular C—H⋯O hydrogen bonds are responsible for the cohesion of the crystal packing. The intermolecular interactions were quantified and analysed using Hirshfeld surface analysis. The molecular structure optimized by density functional theory (DFT) at the B3LYP/6–311++G(d,p)level is compared with the experimentally determined molecular structure in the solid state. Full Article text
ph Synthesis, crystal structure and Hirshfeld surface analysis of 4'-cyano-[1,1'-biphenyl]-4-yl 3-(benzyloxy)benzoate By journals.iucr.org Published On :: 2024-09-12 In the title compound, C27H19O3N, the dihedral angle between the aromatic rings of the biphenyl unit is 38.14 (2)° and the C—O—C—C torsion angle in the benzyloxy benzene fragment is 179.1 (2)°. In the crystal, the molecules are linked by weak C—H⋯O interactions forming S(9) chains propagating along [010]. The most important contributions to the Hirshfeld surface arise from H⋯H (32.4%) and C⋯H/H⋯C (37.0%) contacts. Full Article text
ph Coupling between 2-pyridylselenyl chloride and phenylselenocyanate: synthesis, crystal structure and non-covalent interactions By journals.iucr.org Published On :: 2024-09-17 A new pyridine-fused selenodiazolium salt, 3-(phenylselanyl)[1,2,4]selenadiazolo[4,5-a]pyridin-4-ylium chloride dichloromethane 0.352-solvate, C12H9N2Se2+·Cl−·0.352CH2Cl2, was obtained from the reaction between 2-pyridylselenenyl chloride and phenylselenocyanate. Single-crystal structural analysis revealed the presence of C—H⋯N, C—H⋯Cl−, C—H⋯Se hydrogen bonds as well as chalcogen–chalcogen (Se⋯Se) and chalcogen–halogen (Se⋯Cl−) interactions. Non-covalent interactions were explored by DFT calculations followed by topological analysis of the electron density distribution (QTAIM analysis). The structure consists of pairs of selenodiazolium moieties arranged in a head-to-tail fashion surrounding disordered dichloromethane molecules. The assemblies are connected by C—H⋯Cl− and C—H⋯N hydrogen bonds, forming layers, which stack along the c-axis direction connected by bifurcated Se⋯Cl−⋯H—C interactions. Full Article text
ph Crystal structure and Hirshfeld surface analysis of (E)-N-(2-styrylphenyl)benzenesulfonamide By journals.iucr.org Published On :: 2024-09-20 The crystal structure of the title compound C20H17NO2S features hydrogen-bonding and C—H⋯π interactions. Hirshfeld surface analysis revealed that H⋯H, C⋯H/H⋯C and O⋯H/H⋯O interactions make a major contribution to the crystal packing. Docking studies were carried out to determine the binding affinity and interaction profile of the title compound with EGFR kinase, a member of the ErbB family of receptor tyrosine kinases, which is crucial for processes such as cell proliferation and differentiation. The title compound shows a strong binding affinity with EGFR kinase, with the most favourable conformation having a binding energy of −8.27 kcal mol−1 and a predicted IC50 of 870.34 nM, indicating its potential as a promising candidate for targeted lung cancer therapy. Full Article text
ph Crystal structures of the (η2:η2-cycloocta-1,5-diene)(η6-toluene)iridium(I) cation and μ-chlorido-iridium(III) complexes of 2-(phosphinito)- and 2-(phosphinomethyl)anthraquinone ligands By journals.iucr.org Published On :: 2024-09-30 When reacted in dry, degassed toluene, [Ir(COD)Cl]2 (COD = cycloocta-1,5-diene) and 2 equivalents of 2-(di-tert-butylphosphinito)anthraquinone (tBuPOAQH) were found to form a unique tri-iridium compound consisting of one monoanionic dinuclear tri-μ-chlorido complex bearing one bidentate tBuPOAQ ligand per iridium, which was charge-balanced by an outer sphere [Ir(toluene)(COD)]+ ion, the structure of which has not previously been reported. This product, which is a toluene solvate, namely, (η2:η2-cycloocta-1,5-diene)(η6-toluene)iridium(I) tri-μ-chlorido-bis({3-[(di-tert-butylphosphanyl)oxy]-9,10-dioxoanthracen-2-yl}hydridoiridium(III)) toluene monosolvate, [Ir(C7H8)(C8H12)][Ir2H2(C22H24O3P)2Cl3]·C7H8 or [Ir(toluene)(COD)][Ir(κ-P,C-tBuPOAQ)(H)]2(μ-Cl)3]·toluene, formed as small orange platelets at room temperature, crystallizing in the triclinic space group Poverline{1}. The cation and anion are linked via weak C—H⋯O interactions. The stronger intermolecular attractions are likely the offset parallel π–π interactions, which occur between the toluene ligands of pairs of inverted cations and between pairs of inverted anthraquinone moieties, the latter of which are capped by toluene solvate molecules, making for π-stacks of four molecules each. The related ligand, 2-(di-tert-butylphosphinomethyl)-anthraquinone (tBuPCAQH), did not form crystals suitable for X-ray diffraction under analogous reaction conditions. However, when the reaction was conducted in chloroform, yellow needles readily formed following addition of 1 atm of carbon monoxide. Diffraction studies revealed a neutral, dinuclear, di-μ-chlorido complex, di-μ-chlorido-bis(carbonyl{3-[(di-tert-butylphosphanyl)oxy]-9,10-dioxoanthracen-2-yl}hydridoiridium(I)), [Ir2H2(C23H26O2P)2Cl2(CO)2] or [Ir(κ-P,C-tBuPCAQ)(H)(CO)(μ-Cl)]2, Ir2C48H54Cl2O6P2, again crystallizing in space group Poverline{1}. Offset parallel π–π interactions between anthraquinone groups of adjacent molecules link the molecules in one dimension. Full Article text
ph Synthesis, non-spherical structure refinement and Hirshfeld surface analysis of racemic 2,2'-diisobutoxy-1,1'-binaphthalene By journals.iucr.org Published On :: 2024-09-24 In the racemic title compound, C28H30O2, the naphthyl ring systems subtend a dihedral angle of 68.59 (1)° and the molecular conformation is consolidated by a pair of intramolecular C—H⋯π contacts. The crystal packing features a weak C—H⋯π contact and van der Waals forces. A Hirshfeld surface analysis of the crystal structure reveals that the most significant contributions are from H⋯H (73.2%) and C⋯H/H⋯C (21.2%) contacts. Full Article text
ph Crystal structure and Hirshfeld surface analysis of trichlorido(1,10-phenanthroline-κ2N,N')phenyltin(IV) By journals.iucr.org Published On :: 2024-09-24 The title compound, [Sn(C6H5)Cl3(C12H8N2)], which was obtained by the reaction between 1,10-phenanthroline and phenyltin trichloride in methanol, exhibits intramolecular hydrogen-bonding interactions involving the chlorine and hydrogen atoms. Crystal cohesion is ensured by intermolecular C—H⋯Cl hydrogen bonds, as well as Y—X⋯π and π-stacking interactions involving three different aromatic rings with centroid–centroid distances of 3.6605 (13), 3.9327 (14) and 3.6938 (12) Å]. Hirshfeld surface analysis and the associated two-dimensional fingerprint plots reveal significant contributions from H⋯H (30.7%), Cl⋯H/H⋯Cl (32.4%), and C⋯H/H⋯C (24.0%) contacts to the crystal packing while the C⋯C (6.2%), C⋯Cl/Cl⋯C (4.1%), and N⋯H/H⋯N (1.7%) interactions make smaller contributions. Full Article text
ph Crystal structure and Hirshfeld surface analyses, crystal voids, intermolecular interaction energies and energy frameworks of 3-benzyl-1-(3-bromopropyl)-5,5-diphenylimidazolidine-2,4-dione By journals.iucr.org Published On :: 2024-10-04 The title molecule, C25H23BrN2O2, adopts a cup shaped conformation with the distinctly ruffled imidazolidine ring as the base. In the crystal, weak C—H⋯O hydrogen bonds and C—H⋯π(ring) interactions form helical chains of molecules extending along the b-axis direction that are linked by additional weak C—H⋯π(ring) interactions across inversion centres. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (51.0%), C⋯H/H⋯C (21.3%), Br⋯H/H⋯Br (12.8%) and O⋯H/H⋯O (12.4%) interactions. The volume of the crystal voids and the percentage of free space were calculated to be 251.24 Å3 and 11.71%, respectively, showing that there is no large cavity in the crystal packing. Evaluation of the electrostatic, dispersion and total energy frameworks indicate that the stabilization is dominated by the dispersion energy. Full Article text
ph Structure of 2,3,5-triphenyltetrazol-3-ium chloride hemipentahydrate By journals.iucr.org Published On :: 2024-09-30 The title hydrated molecular salt, C19H15N4+·Cl−·2.5H2O, has two triphenyltetrazolium cations, two chloride anions and five water molecules in the asymmetric unit. The cations differ in the conformations of the phenyl rings with respect to the heterocyclic core, most notably for the C-bonded phenyl ring, for which the N—C—C—C torsion angles differ by 36.4 (3)°. This is likely a result of one cation accepting an O—H⋯N hydrogen bond from a water molecule [O⋯N = 3.1605 (15) Å], while the other cation accepts no hydrogen bonds. In the extended structure, the water molecules are involved in centrosymmetric (H2O)2Cl2 rings as well as (H2O)4 chains. An unusual O—H⋯π interaction and weak C—H⋯O and C—H⋯Cl hydrogen bonds are also observed. Full Article text
ph The crystal structures determination and Hirshfeld surface analysis of N-(4-bromo-3-methoxyphenyl)- and N-{[3-bromo-1-(phenylsulfonyl)-1H-indol-2-yl]methyl}- derivatives of N-{[3-bromo-1-(phenylsulfonyl)-1H-indol- By journals.iucr.org Published On :: 2024-10-04 Two new phenylsulfonylindole derivatives, namely, N-{[3-bromo-1-(phenylsulfonyl)-1H-indol-2-yl]methyl}-N-(4-bromo-3-methoxyphenyl)benzenesulfonamide, C28H22Br2N2O5S2, (I), and N,N-bis{[3-bromo-1-(phenylsulfonyl)-1H-indol-2-yl]methyl}benzenesulfonamide, C36H27Br2N3O6S3, (II), reveal the impact of intramolecular π–π interactions of the indole moieties as a factor not only governing the conformation of N,N-bis(1H-indol-2-yl)methyl)amines, but also significantly influencing the crystal patterns. For I, the crystal packing is dominated by C—H⋯π and π–π bonding, with a particular significance of mutual indole–indole interactions. In the case of II, the molecules adopt short intramolecular π–π interactions between two nearly parallel indole ring systems [with the centroids of their pyrrole rings separated by 3.267 (2) Å] accompanied by a set of forced Br⋯O contacts. This provides suppression of similar interactions between the molecules, while the importance of weak C—H⋯O hydrogen bonding to the packing naturally increases. Short contacts of the latter type [C⋯O = 3.389 (6) Å] assemble pairs of molecules into centrosymmetric dimers with a cyclic R22(13) ring motif. These findings are consistent with the results of a Hirshfeld surface analysis and together they suggest a tool for modulating the supramolecular behavior of phenylsulfonylated indoles. Full Article text
ph Synthesis and crystal structure of sodium (ethane-1,2-diyl)bis[(3-methoxypropyl)phosphinodithiolate] octahydrate By journals.iucr.org Published On :: 2024-10-08 The title compound, catena-poly[[triaquasodium]-di-μ-aqua-[triaquasodium]-μ-(ethane-1,2-diyl)bis[(3-methoxypropyl)phosphinodithiolato]], [Na2(C10H22O2P2S4)(H2O)8]n, crystallizes in the triclinic space group P1. The dianionic [CH3O(CH2)3P(=S)(S—)CH2CH2P(=S)(S—)(CH2)3OCH3]2− ligand fragments are joined by a dicationic [Na2(H2O)8]2+ cluster that includes the oxygen of the methoxypropyl unit of the ligand to form infinite chains. Full Article text
ph Triclinic polymorph of bis[2-methyl-3-(pyridin-2-yl)imidazo[1,5-a]pyridin-2-ium] tetrachloridocadmium(II) By journals.iucr.org Published On :: 2024-10-04 The crystal structure of the title organic–inorganic hybrid salt, (C13H12N3)2[CdCl4], (I), has been reported with four molecules in the asymmetric unit in a monoclinic cell [Vassilyeva et al. (2021). RSC Advances, 11, 7713–7722]. While using two different aldehydes in the oxidative cyclization–condensation involving CH3NH2·HCl to prepare a new monovalent cation with the imidazo[1,5-a]pyridinium skeleton, a new polymorph was obtained for (I) in space group P1 and a unit cell with approximately half the volume of the monoclinic form. The structural configurations of the two crystallographically non-equivalent organic cations as well as the geometry of the moderately distorted tetrahedral CdCl42– dianion show minor changes. In the crystal, identically stacked cations and tetrachlorocadmate anions form separate columns parallel to the a axis. The loose packing of the anions leads to a minimal separation of approximately 9.53 Å between the metal atoms in the triclinic form versus 7.51 Å in the monoclinic one, indicating that the latter is packed slightly more densely. The two forms also differ by aromatic stacking motifs. Similar to the monoclinic polymorph, the triclinic one excited at 364 nm shows an intense unsymmetrical photoluminescent band with maximum at 403 nm and a full width at half maximum of 51 nm in the solid state. Full Article text
ph Crystal structure of a hydrogen-bonded 2:1 co-crystal of 4-nitrophenol and 4,4'-bipyridine By journals.iucr.org Published On :: 2024-10-08 In the title compound, C10H8N2·2C6H5NO3, 4-nitrophenol and 4,4'-bipyridine crystallized together in a 2:1 ratio in the space group P21/n. There is a hydrogen-bonding interaction between the nitrogen atoms on the 4,4'-bipyridine molecule and the hydrogen atom on the hydroxyl group on the 4-nitrophenol, resulting in trimolecular units. This structure is a polymorph of a previously reported structure [Nayak & Pedireddi (2016). Cryst. Growth Des. 16, 5966–5975], which differs mainly due to a twist in the 4,4'-bipyridine molecule. Full Article text
ph Crystal structure, Hirshfeld surface analysis, and DFT and molecular docking studies of 6-cyanonaphthalen-2-yl 4-(benzyloxy)benzoate By journals.iucr.org Published On :: 2024-10-22 In the title compound, C25H17NO3, the torsion angle associated with the phenyl benzoate group is −173.7 (2)° and that for the benzyloxy group is −174.8 (2)° establishing an anti-type conformation. The dihedral angles between the ten-membered cyanonaphthalene ring and the aromatic ring of the phenyl benzoate and the benzyloxy fragments are 40.70 (10) and 87.51 (11)°, respectively, whereas the dihedral angle between the aromatic phenyl benzoate and the benzyloxy fragments is 72.30 (13)°. In the crystal, the molecules are linked by weak C—H⋯O interactions forming S(4) chains propagating parallel to [010]. The packing is consolidated by three C—H⋯π interactions and two π–π stacking interactions between the aromatic rings of naphthalene and phenyl benzoate with centroid-to-centroid distances of 3.9698 (15) and 3.8568 (15) Å, respectively. Intermolecular interactions were quantified using Hirshfeld surface analysis. The molecular structure was further optimized by density functional theory (DFT) at the B3LYP/6–311+ G(d,p) level, revealing that the energy gap between HOMO and LUMO is 3.17 eV. Molecular docking studies were carried out for the title compound as a ligand and SARS-Covid-2(PDB ID:7QF0) protein as a receptor giving a binding affinity of −9.5 kcal mol−1. Full Article text
ph Crystal structure of an acetonitrile solvate of 2-(3,4,5-triphenylphenyl)acetic acid By journals.iucr.org Published On :: 2024-10-24 Crystal growth of 2-(3,4,5-triphenylphenyl)acetic acid (1) from acetonitrile yields a monosolvate, C26H20O2·CH3CN, of the space group P1. In the crystal, the title molecule adopts a conformation in which the three phenyl rings are arranged in a paddlewheel-like fashion around the central arene ring and the carboxyl residue is oriented nearly perpendicular to the plane of this benzene ring. Inversion-symmetric dimers of O—H⋯O-bonded molecules of 1 represent the basic supramolecular entities of the crystal structure. These dimeric molecular units are further linked by C—H⋯O=C bonds to form one-dimensional supramolecular aggregates running along the crystallographic [111] direction. Weak Caryl—H⋯N interactions occur between the molecules of 1 and acetonitrile. Full Article text
ph Synthesis and structure of trans-2,5-dimethylpiperazine-1,4-diium dihydrogen diphosphate By journals.iucr.org Published On :: 2024-10-24 In the title salt, C6H16N22+ ·H2P2O72−, the complete dication is generated by a crystallographic centre of symmetry with the methyl groups in equatorial orientations. The complete dianion is generated by a crystallographic twofold axis with the central O atom lying on the axis: the P—O—P bond angle is 135.50 (12)°. In the crystal, the dihydrogen diphosphate anions are linked by O—H⋯O hydrogen bonds, generating (001) layers. The organic cations bond to the inorganic layers by way of N—H⋯O and C—H⋯O hydrogen bonds. A Hirshfeld surface analysis shows that the most important contributions for the crystal packing are from O⋯H/H⋯O (60.5%) and H⋯H (39.4%) contacts. Full Article text
ph Synthesis, crystal structure and Hirshfeld surface analysis of 2-{4-[(2-chlorophenyl)methyl]-3-methyl-6-oxopyridazin-1-yl}-N-phenylacetamide By journals.iucr.org Published On :: 2024-10-31 In the title molecule, C20H18ClN3O2, the 2-chlorophenyl group is disordered to a small extent [occupancies 0.875 (2)/0.125 (2)]. The phenylacetamide moiety is nearly planar due to a weak, intramolecular C—H⋯O hydrogen bond. In the crystal, N—H⋯O hydrogen bonds and π-stacking interactions between pyridazine and phenyl rings form helical chains of molecules in the b-axis direction, which are linked by C—H⋯O hydrogen bonds and C—H⋯π(ring) interactions. A Hirshfeld surface analysis was performed, which showed that H⋯H, C⋯H/H⋯C and O⋯H/H⋯O interactions to dominate the intermolecular contacts in the crystal. Full Article text
ph Crystal structures and photophysical properties of mono- and dinuclear ZnII complexes flanked by triethylammonium By journals.iucr.org Published On :: 2024-10-24 Two new zinc(II) complexes, triethylammonium dichlorido[2-(4-nitrophenyl)-4-phenylquinolin-8-olato]zinc(II), (C6H16N){Zn(C21H13N2O3)Cl2] (ZnOQ), and bis(triethylammonium) {2,2'-[1,4-phenylenebis(nitrilomethylidyne)]diphenolato}bis[dichloridozinc(II)], (C6H16N)2[Zn2(C20H14N2O2)Cl4] (ZnBS), were synthesized and their structures were determined using ESI–MS spectrometry, 1H NMR spectroscopy, and single-crystal X-ray diffraction. The results showed that the ligands 2-(4-nitrophenyl)-4-phenylquinolin-8-ol (HOQ) and N,N'-bis(2-hydroxybenzylidene)benzene-1,4-diamine (H2BS) were deprotonated by triethyl-amine, forming the counter-ion Et3NH+, which interacts via an N—H⋯O hydrogen bond with the ligand. The ZnII atoms have a distorted trigonal–pyramidal (ZnOQ) and distorted tetrahedral (ZnBS) geometries with a coordination number of four, coordinating with the ligands via N and O atoms. The N atoms coordinating with ZnII correspond to the heterocyclic nitrogen for the HOQ ligand, while for the H2BS ligand, it is the nitrogen of the imine (CH=N). The crystal packing of ZnOQ is characterized by C—H⋯π interactions, while that of ZnBS by C—H⋯Cl interactions. The emission spectra showed that ZnBS complex exhibits green fluorescence in the solid state with a small band-gap energy, and the ZnOQ complex does exhibit non-fluorescence. Full Article text
ph Crystal structure of bis{5-(4-chlorophenyl)-3-[6-(1H-pyrazol-1-yl)pyridin-2-yl]-1H-1,2,4-triazol-1-ido}nickel(II) methanol disolvate By journals.iucr.org Published On :: 2024-10-31 The unit cell of the title compound, [Ni(C16H10ClN6)2]·2CH3OH, consists of a neutral complex and two methanol molecules. In the complex, the two tridentate 2-(3-(4-chlorophenyl)-1H-1,2,4-triazol-5-yl)-6-(1H-pyrazol-1-yl)pyridine ligands coordinate to the central NiII ion through the N atoms of the pyrazole, pyridine and triazole groups, forming a pseudooctahedral coordination sphere. Neighbouring tapered molecules are linked through weak C—H(pz)⋯π(ph) interactions into monoperiodic chains, which are further linked through weak C—H⋯N/C interactions into diperiodic layers. The intermolecular contacts were quantified using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing the relative contributions of the contacts to the crystal packing to be H⋯H 32.8%, C⋯H/H⋯C 27.5%, N⋯H/H⋯N 15.1%, and Cl⋯H/H⋯Cl 14.0%. The average Ni—N bond distance is 2.095 Å. Energy framework analysis at the HF/3–21 G theory level was performed to quantify the interaction energies in the crystal structure. Full Article text
ph Development of MHz X-ray phase contrast imaging at the European XFEL By journals.iucr.org Published On :: The development of instrumentation as well as applications for megahertz X-ray phase contrast imaging at the Single Particles, Clusters, and Biomolecules and Serial Femtosecond Crystallography instrument of the European XFEL are introduced here. Full Article text
ph Review and experimental comparison of speckle-tracking algorithms for X-ray phase contrast imaging By journals.iucr.org Published On :: This review focuses on low-dose near-field X-ray speckle phase imaging in the differential mode introducing the existing algorithms with their specifications and comparing their performances under various experimental conditions. Full Article text
ph The use of ethanol as contrast enhancer in Synchrotron X-ray phase-contrast imaging leads to heterogeneous myocardial tissue shrinkage: a case report By journals.iucr.org Published On :: In this work, we showed that the use of ethanol to increase image contrast when imaging cardiac tissue with synchrotron X-ray phase-contrast imaging (X-PCI) leads to heterogeneous tissue shrinkage, which has an impact on the 3D organization of the myocardium. Full Article text
ph Fast nanoscale imaging of strain in a multi-segment heterostructured nanowire with 2D Bragg ptychography By journals.iucr.org Published On :: 2024-02-01 Developing semiconductor devices requires a fast and reliable source of strain information with high spatial resolution and strain sensitivity. This work investigates the strain in an axially heterostructured 180 nm-diameter GaInP nanowire with InP segments of varying lengths down to 9 nm, simultaneously probing both materials. Scanning X-ray diffraction (XRD) is compared with Bragg projection ptychography (BPP), a fast single-projection method. BPP offers a sufficient spatial resolution to reveal fine details within the largest segments, unlike scanning XRD. The spatial resolution affects the quantitative accuracy of the strain maps, where BPP shows much-improved agreement with an elastic 3D finite element model compared with scanning XRD. The sensitivity of BPP to small deviations from the Bragg condition is systematically investigated. The experimental confirmation of the model suggests that the large lattice mismatch of 1.52% is accommodated without defects. Full Article text
ph A note on the Hendrickson–Lattman phase probability distribution and its equivalence to the generalized von Mises distribution By journals.iucr.org Published On :: 2024-02-16 Hendrickson & Lattman [Acta Cryst. (1970), B26, 136–143] introduced a method for representing crystallographic phase probabilities defined on the unit circle. Their approach could model the bimodal phase probability distributions that can result from experimental phase determination procedures. It also provided simple and highly effective means to combine independent sources of phase information. The present work discusses the equivalence of the Hendrickson–Lattman distribution and the generalized von Mises distribution of order two, which has been studied in the statistical literature. Recognizing this connection allows the Hendrickson–Lattman distribution to be expressed in an alternative form which is easier to interpret, as it involves the location and concentration parameters of the component von Mises distributions. It also allows clarification of the conditions for bimodality and access to a simplified analytical method for evaluating the trigonometric moments of the distribution, the first of which is required for computing the best Fourier synthesis in the presence of phase, but not amplitude, uncertainty. Full Article text
ph Revisiting the hydrogenation behavior of NdGa and its hydride phases By journals.iucr.org Published On :: 2024-02-16 NdGa hydride and deuteride phases were prepared from high-quality NdGa samples and their structures characterized by powder and single-crystal X-ray diffraction and neutron powder diffraction. NdGa with the orthorhombic CrB-type structure absorbs hydrogen at hydrogen pressures ≤ 1 bar until reaching the composition NdGaH(D)1.1, which maintains a CrB-type structure. At elevated hydrogen pressure additional hydrogen is absorbed and the maximum composition recovered under standard temperature and pressure conditions is NdGaH(D)1.6 with the Cmcm LaGaH1.66-type structure. This structure is a threefold superstructure with respect to the CrB-type structure. The hydrogen atoms are ordered and distributed on three fully occupied Wyckoff positions corresponding to tetrahedral (4c, 8g) and trigonal–bipyramidal (8g) voids in the parent structure. The threefold superstructure is maintained in the H-deficient phases NaGaH(D)x until 1.6 ≥ x ≥ 1.2. At lower H concentrations, coinciding with the composition of the hydride obtained from hydrogenation at atmospheric pressure, the unit cell of the CrB-type structure is resumed. This phase can also display H deficiency, NdGaH(D)y (1.1 ≥ y ≥ 0.9), with H(D) exclusively situated in partially empty tetrahedral voids. The phase boundary between the threefold superstructure (LaGaH1.66 type) and the onefold structure (NdGaH1.1 type) is estimated on the basis of phase–composition isotherms and neutron powder diffraction to be x = 1.15. Full Article text
ph A workflow for single-particle structure determination via iterative phasing of rotational invariants in fluctuation X-ray scattering By journals.iucr.org Published On :: 2024-03-15 Fluctuation X-ray scattering (FXS) offers a complementary approach for nano- and bioparticle imaging with an X-ray free-electron laser (XFEL), by extracting structural information from correlations in scattered XFEL pulses. Here a workflow is presented for single-particle structure determination using FXS. The workflow includes procedures for extracting the rotational invariants from FXS patterns, performing structure reconstructions via iterative phasing of the invariants, and aligning and averaging multiple reconstructions. The reconstruction pipeline is implemented in the open-source software xFrame and its functionality is demonstrated on several simulated structures. Full Article text
ph Robust image descriptor for machine learning based data reduction in serial crystallography By journals.iucr.org Published On :: 2024-03-26 Serial crystallography experiments at synchrotron and X-ray free-electron laser (XFEL) sources are producing crystallographic data sets of ever-increasing volume. While these experiments have large data sets and high-frame-rate detectors (around 3520 frames per second), only a small percentage of the data are useful for downstream analysis. Thus, an efficient and real-time data classification pipeline is essential to differentiate reliably between useful and non-useful images, typically known as `hit' and `miss', respectively, and keep only hit images on disk for further analysis such as peak finding and indexing. While feature-point extraction is a key component of modern approaches to image classification, existing approaches require computationally expensive patch preprocessing to handle perspective distortion. This paper proposes a pipeline to categorize the data, consisting of a real-time feature extraction algorithm called modified and parallelized FAST (MP-FAST), an image descriptor and a machine learning classifier. For parallelizing the primary operations of the proposed pipeline, central processing units, graphics processing units and field-programmable gate arrays are implemented and their performances compared. Finally, MP-FAST-based image classification is evaluated using a multi-layer perceptron on various data sets, including both synthetic and experimental data. This approach demonstrates superior performance compared with other feature extractors and classifiers. Full Article text