irs Expert Available: GOP Sets Sights on Legislative Agenda for Trump's First 100 Days By www.newswise.com Published On :: Mon, 11 Nov 2024 12:00:36 EST House Republicans are preparing a legislative agenda for Trump's first 100 days in office. ... Full Article
irs First Case of Highly Pathogenic AI This Fall Confirmed in Gangwon Province By world.kbs.co.kr Published On :: Wed, 30 Oct 2024 17:18:54 +0900 [Domestic] : The nation has confirmed its first case of highly pathogenic avian influenza so far this fall season at a poultry farm in Gangwon Province. Quarantine authorities said Wednesday that the birds at the farm in Donghae had the highly pathogenic H5N1 strain of the virus. The farm, which raises some 700 ...[more...] Full Article Domestic
irs KDCA: Infant Dies from Whooping Cough, First Related Death in S. Korea By world.kbs.co.kr Published On :: Tue, 12 Nov 2024 15:11:31 +0900 [Domestic] : A death from whooping cough or pertussis has been reported in South Korea for the first time since the government began compiling related data in 2011. According to the Korea Disease Control and Prevention Agency(KDCA) on Tuesday, an infant less than two months old died from the disease on November 4. The ...[more...] Full Article Domestic
irs Main Opposition Passes Special Counsel Bill Against First Lady By world.kbs.co.kr Published On :: Fri, 08 Nov 2024 18:08:19 +0900 [Politics] : A special counsel bill aimed at investigating various allegations surrounding First Lady Kim Keon-hee was passed at the National Assembly's legislation and judiciary committee meeting on Friday. The bill was passed unilaterally at the parliamentary judiciary subcommittee by members of the opposition after ...[more...] Full Article Politics
irs Power Broker Myung Tae-kyun Denies Allegations Linked to First Lady By world.kbs.co.kr Published On :: Sat, 09 Nov 2024 14:21:05 +0900 [Politics] : Myung Tae-kyun, a self-proclaimed political consultant and a key figure in a high-profile scandal involving the president and first lady, appeared for questioning for the second consecutive day. Prior to interrogation by the Changwon District Prosecutors' Office on Saturday, Myung once again denied ...[more...] Full Article Politics
irs Opposition to Submit Revised Bill on First Lady, Limiting Scope of Investigation By world.kbs.co.kr Published On :: Mon, 11 Nov 2024 15:01:01 +0900 [Politics] : The opposition will submit a revised version of its bill mandating a special prosecutor to investigate allegations against first lady Kim Keon-hee, limiting the scope of the probe in an apparent effort to win votes from the ruling party when the bill returns to parliament for a revote after an expected ...[more...] Full Article Politics
irs Ruling Party Floor Leader to Recommend President Veto First Lady Special Counsel Bill By world.kbs.co.kr Published On :: Mon, 11 Nov 2024 15:36:47 +0900 [Politics] : If the opposition unilaterally passes a bill mandating a special counsel investigation targeting first lady Kim Keon-hee, ruling People Power Party floor leader Choo Kyung-ho has said he will strongly recommend a presidential veto. At a party Supreme Council meeting Monday, Choo said the ruling party ...[more...] Full Article Politics
irs S. Korea Defeats Oman 3-1 for First Win in World Cup Qualifiers By world.kbs.co.kr Published On :: Wed, 11 Sep 2024 08:23:46 +0900 [Sports] : South Korea defeated Oman three to one, achieving its first win in the current World Cup qualifying campaign. The South Korean national soccer team, led by head coach Hong Myung-bo, played Oman on Tuesday at the Sultan Qaboos Sports Complex in Muscat in the second Group B match in the third round of the ...[more...] Full Article Sports
irs Son Heung-min Earns First Two Assists of Season in Premier League Win By world.kbs.co.kr Published On :: Sun, 22 Sep 2024 12:19:36 +0900 [Sports] : South Korean forward Son Heung-min of the Tottenham Hotspur has picked up his first two assists of the season, helping his club with the second win of the season. Son set up Brennan Johnson's 28th-minute goal in a match against Brentford on Saturday at Tottenham Hotspur Stadium in London, breaking ...[more...] Full Article Sports
irs First Frost of Season Reported in Seoul and Daejeon By world.kbs.co.kr Published On :: Wed, 06 Nov 2024 15:16:01 +0900 [Science] : Seoul, Daejeon and other inland areas experienced the first frost of the fall season Wednesday. In Seoul and Suwon, Gyeonggi Province, the first frost was observed two days earlier than last year and nine days later than average. Daejeon reported its first frost 16 days later than last year and nine ...[more...] Full Article Science
irs Navy Flies Fixed-Wing Drone from Vessel for First Time By world.kbs.co.kr Published On :: Wed, 13 Nov 2024 13:47:24 +0900 [Politics] : The Navy flew a fixed-wing drone from one of its vessels for the first time as part of its efforts to advance technology for unmanned aerial vehicles. The Navy said a prototype of the Mojave drone, developed by the U.S. firm General Atomics Aeronautical Systems, took off Tuesday from the 14-thousand-ton ...[more...] Full Article Politics
irs Opposition Party to Protest First Couple at Gwanghwamun Rally By world.kbs.co.kr Published On :: Wed, 13 Nov 2024 14:16:29 +0900 [Politics] : The main opposition Democratic Party(DP) will stage a rally this weekend to denounce alleged influence peddling by President Yoon Suk Yeol and first lady Kim Keon-hee and call for a special counsel probe. DP spokesperson Hwang Jung-a said Wednesday that the party will hold the rally in Seoul’s ...[more...] Full Article Politics
irs Andy Kim Wins in New Jersey, Becoming First Korean American Senator By world.kbs.co.kr Published On :: Wed, 06 Nov 2024 11:12:11 +0900 [International] : Democratic Rep. Andy Kim was elected to the U.S. Senate on Tuesday, becoming the first Korean American to serve in the Senate. With elections for the Senate and the House of Representatives taking place the same day as the U.S. presidential election, Kim defeated Curtis Bashaw in the New Jersey senatorial ...[more...] Full Article International
irs Bitcoin Price Hits $80,000 Mark for First Time By world.kbs.co.kr Published On :: Mon, 11 Nov 2024 08:36:49 +0900 [International] : The price of Bitcoin surpassed the 80-thousand-dollar mark for the first time just days after Donald Trump’s reelection to the U.S. presidency. According to the U.S. cryptocurrency exchange platform Coinbase, the world’s most popular cryptocurrency was worth 81-thousand-110 U.S. dollars at 1:25 a.m. ...[more...] Full Article International
irs P1Harmony Unveils Cover for First Album in Japan By world.kbs.co.kr Published On :: 2024-05-03 P1Harmony is set to release a best-hits album in Japan.According to the six-member boy group's agency FNC Entertainment on Friday, 'Love & P1ece : The Best of P1Harmony' will be released on August 21. It...[more...] Full Article
irs Babymonster to kick off first global fan meet this week By world.kbs.co.kr Published On :: 2024-05-06 Rookie girl group Babymonster will embark on its first global fan meet tour this week. “Babymonster Presents: See You There” will begin in Tokyo on May 11. The tour will also travel to Jakarta,...[more...] Full Article
irs Seventeen becomes UNESCO's first Goodwill Ambassador for Youth By world.kbs.co.kr Published On :: 2024-06-17 Seventeen has become the 1st K-pop group to be appointed UNESCO's Goodwill Ambassador for Youth. It is also the first time UNESCO has designated a youth ambassador. Seventeen has been supporting the...[more...] Full Article
irs Minho to Hold First Solo Concert in November By world.kbs.co.kr Published On :: 2024-10-08 +09:00 Minho of SHINee will hold his first solo concert in November. Titled “MEAN: of my first” it will be Minho’s first solo concert since his debut as a member of SHINee in 2008....[more...] Full Article Economy&It
irs H1-Key to Launch First Fan Concert Next Month By world.kbs.co.kr Published On :: 2024-10-22 +09:00 H1-Key is set to embark on its first fan concert tour next month. The group will kick off the tour called “Find My KEY” in Hong Kong on Nov. 16 and will travel to other regions...[more...] Full Article Economy&It
irs Jin to Release First Solo Album By world.kbs.co.kr Published On :: 2024-10-22 +09:00 Jin of BTS will release his first solo album next month. Titled “Happy” the album will drop on Nov. 15. His label, BigHit Music, said “Happy” is about finding happiness...[more...] Full Article Economy&It
irs Exports Fall 17.8% for First 10 Days of November By world.kbs.co.kr Published On :: Mon, 11 Nov 2024 10:10:10 +0900 [Economy] : Exports fell more than 17 percent year-on-year in the first ten days of November because there were fewer working days. According to preliminary data from the Korea Customs Service on Monday, the country’s outbound shipments reached 14-point-nine billion U.S. dollars during the cited period, down ...[more...] Full Article Economy
irs KOSPI Slips below 2,500 Threshold for First Time since Black Monday in August By world.kbs.co.kr Published On :: Tue, 12 Nov 2024 17:55:50 +0900 [Economy] : South Korea’s benchmark Korea Composite Stock Price Index(KOSPI) slipped below the two-thousand-500 threshold on Tuesday for the first time since August’s “Black Monday.” The KOSPI dipped 49-point-09 points, or one-point-94 percent, on Tuesday to close at two-thousand-482-point-57. In the ...[more...] Full Article Economy
irs KOSDAQ Falls below 700 for First Time in 2 Months By world.kbs.co.kr Published On :: Wed, 13 Nov 2024 11:20:48 +0900 [Economy] : South Korea’s tech-laden KOSDAQ fell below the 700 mark during trading for the first time in two months. As of 10:12 a.m. Wednesday, the secondary KOSDAQ market stood at 697-point-94, down 12-point-58 points or one-point-77 percent from the previous day. It marks the first time the KOSDAQ has ...[more...] Full Article Economy
irs BGS completes first mapping expedition to Ascension Island - British Geological Survey By news.google.com Published On :: Mon, 11 Dec 2023 08:00:00 GMT BGS completes first mapping expedition to Ascension Island British Geological Survey Full Article
irs First national-scale groundwater model in Great Britain developed - British Geological Survey By news.google.com Published On :: Tue, 14 May 2024 10:50:37 GMT First national-scale groundwater model in Great Britain developed British Geological Survey Full Article
irs Crystal structure predictions for molecules with soft degrees of freedom using intermonomer force fields derived from first principles By journals.iucr.org Published On :: Full Article text
irs First crystal structure of the DUF2436 domain of virulence proteins from Porphyromonas gingivalis By journals.iucr.org Published On :: 2024-09-26 Porphyromonas gingivalis is a major pathogenic oral bacterium that is responsible for periodontal disease. It is linked to chronic periodontitis, gingivitis and aggressive periodontitis. P. gingivalis exerts its pathogenic effects through mechanisms such as immune evasion and tissue destruction, primarily by secreting various factors, including cysteine proteases such as gingipain K (Kgp), gingipain R (RgpA and RgpB) and PrtH (UniProtKB ID P46071). Virulence proteins comprise multiple domains, including the pro-peptide region, catalytic domain, K domain, R domain and DUF2436 domain. While there is a growing database of knowledge on virulence proteins and domains, there was no prior evidence or information regarding the structure and biological function of the well conserved DUF2436 domain. In this study, the DUF2436 domain of PrtH from P. gingivalis (PgDUF2436) was determined at 2.21 Å resolution, revealing a noncanonical β-jelly-roll sandwich topology with two antiparallel β-sheets and one short α-helix. Although the structure of PgDUF2436 was determined by the molecular-replacement method using an AlphaFold model structure as a template, there were significant differences in the positions of β1 between the AlphaFold model and the experimentally determined PgDUF2436 structure. The Basic Local Alignment Search Tool sequence-similarity search program showed no sequentially similar proteins in the Protein Data Bank. However, DaliLite search results using structure-based alignment revealed that the PgDUF2436 structure has structural similarity Z-scores of 5.9–5.4 with the C-terminal domain of AlgF, the D4 domain of cytolysin, IglE and the extracellular domain structure of PepT2. This study has elucidated the structure of the DUF2436 domain for the first time and a comparative analysis with similar structures has been performed. Full Article text
irs Exploiting Friedel pairs to interpret scanning 3DXRD data from complex geological materials By journals.iucr.org Published On :: A new processing technique for synchrotron scanning 3D X-ray diffraction data is introduced, utilizing symmetric Bragg reflections hkl and hkl, known as Friedel pairs. This technique is designed to tackle the difficulties associated with large, highly deformed, polyphase materials, especially geological samples. Full Article text
irs Crystal structure and Hirshfeld surface analysis of bis(benzoylacetonato)(ethanol)dioxidouranium(VI) By journals.iucr.org Published On :: In the complex, the ligand binds to the metal through an oxygen atom. The geometry of the seven-coordinate U atom is pentagonal bipyramidal, with the uranyl O atoms in apical positions. Full Article text
irs Crystal structure and Hirshfeld-surface analysis of an etoxazole metabolite designated R13 By journals.iucr.org Published On :: The crystal structure of a metabolite of the insecticide/acaricide etoxazole, designated R13 is presented along with a Hirshfeld surface analysis of intermolecular interactions present in the crystal structure. Full Article text
irs Crystal structure, Hirshfeld surface analysis, DFT and molecular docking studies of ethyl 5-amino-2-bromoisonicotinate By journals.iucr.org Published On :: Theoretical and experimental structural studies of the title compound were undertaken using X-ray and DFT methods. The interactions present in the crystal were analyzed using Hirshfeld surface and MEP surface analysis. Docking studies with a covid-19 main protease (PDB ID: 6LU7) as the target receptor indicate that the synthesized compound may be a potential candidate for pharmaceutical applications. Full Article text
irs Crystal structure, Hirshfeld surface, DFT and molecular docking studies of 2-{4-[(E)-(4-acetylphenyl)diazenyl]phenyl}-1-(5-bromothiophen-2-yl)ethanone; a bromine⋯oxygen type contact By journals.iucr.org Published On :: The title compound is a non-liquid crystal molecule. The molecular crystal is consolidated by C—Br⋯O&z-dbnd;C type contacts running continuously along the [001] direction. Full Article text
irs Synthesis, crystal structure and Hirshfeld surface analysis of N-(4-methoxyphenyl)picolinamide By journals.iucr.org Published On :: The molecular and crystal structure of N-(4-methoxyphenyl)picolinamide were studied and Hirshfeld surfaces and fingerprint plots were generated to investigate various intermolecular interactions. Full Article text
irs Exploiting Friedel pairs to interpret scanning 3DXRD data from complex geological materials By journals.iucr.org Published On :: 2024-11-08 The present study introduces a processing strategy for synchrotron scanning 3D X-ray diffraction (s3DXRD) data, aimed at addressing the challenges posed by large, highly deformed, polyphase materials such as crystalline rocks. Leveraging symmetric Bragg reflections known as Friedel pairs, our method enables diffraction events to be precisely located within the sample volume. This method allows for fitting the phase, crystal structure and unit-cell parameters at the intra-grain scale on a voxel grid. The processing workflow incorporates several new modules, designed to (i) efficiently match Friedel pairs in large s3DXRD datasets containing up to 108 diffraction peaks; (ii) assign phases to each pixel or voxel, resolving potential ambiguities arising from overlap in scattering angles between different crystallographic phases; and (iii) fit the crystal orientation and unit cell locally on a point-by-point basis. We demonstrate the effectiveness of our technique on fractured granite samples, highlighting the ability of the method to characterize complex geological materials and show their internal structure and mineral composition. Additionally, we include the characterization of a metal gasket made of a commercial aluminium alloy, which surrounded the granite sample during experiments. The results show the effectiveness of the technique in recovering information about the internal texture and residual strain of materials that have undergone high levels of plastic deformation. Full Article text
irs Crystal structure, Hirshfeld surface analysis, DFT and molecular docking studies of ethyl 5-amino-2-bromoisonicotinate By journals.iucr.org Published On :: 2024-11-08 In the title compound, C8H9BrN2O2, the C—O—C—C torsion angle between isonicotine and the ethyl group is 180.0 (2)°. Intramolecular N—H...O and C—H...O interactions consolidate the molecular structure. In the crystal, N—H...N interaction form S(5) zigzag chains along [010]. The most significant contributions to the Hirshfeld surface arise from H...H (33.2%), Br...H/H...Br (20.9%), O...H/H...O (11.2%), C...H/H...C (11.1%) and N...H/H...N (10%) contacts. The topology of the three-dimensional energy frameworks was generated using the B3LYP/6–31 G(d,p) model to calculate the total interaction energy. The net interaction energies for the title compound are Eele = 59.2 kJ mol−1, Epol = 15.5 kJ mol−1, Edis = 140.3 kJ mol−1 and Erep = 107.2 kJ mol−1 with a total interaction energy Etot of 128.8 kJ mol−1. The molecular structure was optimized by density functional theory (DFT) at the B3LYP/6–311+G(d,p) level and the theoretical and experimentally obtained parameters were compared. The frontier molecular orbitals HOMO and LUMO were generated, giving an energy gap ΔE of 4.0931 eV. The MEP was generated to identify active sites in the molecule and molecular docking studies carried out with the title compound (ligand) and the covid-19 main protease PDB ID: 6LU7, revealing a moderate binding affinity of −5.4 kcal mol−1. Full Article text
irs Crystal structure and Hirshfeld-surface analysis of an etoxazole metabolite designated R13 By journals.iucr.org Published On :: 2024-11-08 The etoxazole metabolite R13, systematic name 4-(4-tert-butyl-2-ethoxyphenyl)-2-(2,6-difluorophenyl)oxazole (C21H21F2NO2), results from the oxidation of etoxazole, a chitin synthesis inhibitor belonging to the oxazoline class, widely used as an insecticide/acaricide since 1998. The structure of R13 features a central oxazole ring with attached 2,6-difluorophenyl and 4-t-butyl-2-ethoxyphenyl moieties. The overall conformation gives dihedral angles between these rings and the oxazole of 24.91 (5)° (with difluorophenyl) and 15.30 (6)° (with t-butyl-ethoxyphenyl), indicating an overall deviation from planarity. Additionally, torsion angles of the ethoxy and t-butyl groups define the orientation of these substituents relative to their benzene ring. In the crystal packing, no significant hydrogen bonds are present, but a Hirshfeld surface analysis highlights weak intermolecular contacts leading to π–π-stacked dimers linked by weak C—H...N contacts. The packing analysis confirms that most intermolecular interactions involve hydrogen atoms. Full Article text
irs First X-ray spectral ptychography and resonant ptychographic computed tomography experiments at the SWING beamline from Synchrotron SOLEIL By journals.iucr.org Published On :: 2024-05-21 X-ray ptychography and ptychographic computed tomography have seen a rapid rise since the advent of fourth-generation synchrotrons with a high degree of coherent radiation. In addition to quantitative multiscale structural analysis, ptychography with spectral capabilities has been developed, allowing for spatial-localized multiscale structural and spectral information of samples. The SWING beamline of Synchrotron SOLEIL has recently developed a nanoprobe setup where the endstation's first spectral and resonant ptychographic measurements have been successfully conducted. A metallic nickel wire sample was measured using 2D spectral ptychography in XANES mode and resonant ptychographic tomography. From the 2D spectral ptychography measurements, the spectra of the components of the sample's complex-valued refractive index, δ and β, were extracted, integrated along the sample thickness. By performing resonance ptychographic tomography at two photon energies, 3D maps of the refractive index decrement, δ, were obtained at the Ni K-edge energy and another energy above the edge. These maps allowed the detection of impurities in the Ni wire. The significance of accounting for the atomic scattering factor is demonstrated in the calculation of electron density near a resonance through the use of the δ values. These results indicate that at the SWING beamline it is possible to conduct state-of-the-art spectral and resonant ptychography experiments using the nanoprobe setup. Full Article text
irs α-d-2'-Deoxyadenosine, an irradiation product of canonical DNA and a component of anomeric nucleic acids: crystal structure, packing and Hirshfeld surface analysis By journals.iucr.org Published On :: 2024-01-22 α-d-2'-Deoxyribonucleosides are products of the γ-irradiation of DNA under oxygen-free conditions and are constituents of anomeric DNA. They are not found as natural building blocks of canonical DNA. Reports on their conformational properties are limited. Herein, the single-crystal X-ray structure of α-d-2'-deoxyadenosine (α-dA), C10H13N5O3, and its conformational parameters were determined. In the crystalline state, α-dA forms two conformers in the asymmetric unit which are connected by hydrogen bonds. The sugar moiety of each conformer is arranged in a `clamp'-like fashion with respect to the other conformer, forming hydrogen bonds to its nucleobase and sugar residue. For both conformers, a syn conformation of the nucleobase with respect to the sugar moiety was found. This is contrary to the anti conformation usually preferred by α-nucleosides. The sugar conformation of both conformers is C2'-endo, and the 5'-hydroxyl groups are in a +sc orientation, probably due to the hydrogen bonds formed by the conformers. The formation of the supramolecular assembly of α-dA is controlled by hydrogen bonding and stacking interactions, which was verified by a Hirshfeld and curvedness surface analysis. Chains of hydrogen-bonded nucleobases extend parallel to the b direction and are linked to equivalent chains by hydrogen bonds involving the sugar moieties to form a sheet. A comparison of the solid-state structures of the anomeric 2'-deoxyadenosines revealed significant differences of their conformational parameters. Full Article text
irs Using cocrystals as a tool to study non-crystallizing molecules: crystal structure, Hirshfeld surface analysis and computational study of the 1:1 cocrystal of (E)-N-(3,4-difluorophenyl)-1-(pyridin-4-yl)methanimine and acetic By journals.iucr.org Published On :: 2024-07-05 Using a 1:1 cocrystal of (E)-N-(3,4-difluorophenyl)-1-(pyridin-4-yl)methanimine with acetic acid, C12H8F2N2·C2H4O2, we investigate the influence of F atoms introduced to the aromatic ring on promoting π–π interactions. The cocrystal crystallizes in the triclinic space group P1. Through crystallographic analysis and computational studies, we reveal the molecular arrangement within this cocrystal, demonstrating the presence of hydrogen bonding between the acetic acid molecule and the pyridyl group, along with π–π interactions between the aromatic rings. Our findings highlight the importance of F atoms in promoting π–π interactions without necessitating full halogenation of the aromatic ring. Full Article text
irs Na[GeF5]·2HF: the first quarternary phase in the H–Na–Ge–F system By journals.iucr.org Published On :: 2024-07-10 The structure of cis- or trans-bridged [GeF5]− anionic chains have been investigated [Mallouk et al. (1984). Inorg. Chem. 23, 3160–3166] showing the first crystal structures of μ-F-bridged pentafluorogermanates. Herein, we report the second crystal structure of trans-pentafluorogermanate anions present in the crystal structure of sodium trans-pentafluorogermanate(IV) bis(hydrogen fluoride), Na[GeF5]·2HF. The crystal structure [orthorhombic Pca21, a = 12.3786 (3), b = 7.2189 (2), c = 11.4969 (3) Å and Z = 8] is built up from infinite chains of trans-linked [GeF6]2− octahedra, extending along the b axis and spanning a network of pentagonal bipyramidal distorted Na-centred polyhedra. These [NaF7] polyhedra are linked in a trans-edge fashion via hydrogen fluoride molecules, in analogy to already known sodium hydrogen fluorides and potassium hydrogen fluorides. Full Article text
irs Synthesis of organotin(IV) heterocycles containing a xanthenyl group by a Barbier approach via ultrasound activation: synthesis, crystal structure and Hirshfeld surface analysis By journals.iucr.org Published On :: 2024-07-25 A series of organotin heterocycles of general formula [{Me2C(C6H3CH2)2O}SnR2] [R = methyl (Me, 4), n-butyl (n-Bu, 5), benzyl (Bn, 6) and phenyl (Ph, 7)] was easily synthesized by a Barbier-type reaction assisted by the sonochemical activation of metallic magnesium. The 119Sn{1H} NMR data for all four compounds confirm the presence of a central Sn atom in a four-coordinated environment in solution. Single-crystal X-ray diffraction studies for 17,17-dimethyl-7,7-diphenyl-15-oxa-7-stannatetracyclo[11.3.1.05,16.09,14]heptadeca-1,3,5(16),9(14),10,12-hexaene, [Sn(C6H5)2(C17H16O)], 7, at 100 and 295 K confirmed the formation of a mononuclear eight-membered heterocycle, with a conformation depicted as boat–chair, resulting in a weak Sn⋯O interaction. The Sn and O atoms are surrounded by hydrophobic C—H bonds. A Hirshfeld surface analysis of 7 showed that the eight-membered heterocycles are linked by weak C—H⋯π, π–π and H⋯H noncovalent interactions. The pairwise interaction energies showed that the cohesion between the heterocycles are mainly due to dispersion forces. Full Article text
irs Further evaluation of the shape of atomic Hirshfeld surfaces: M⋯H contacts and homoatomic bonds By journals.iucr.org Published On :: 2024-08-08 It is well known that Hirshfeld surfaces provide an easy and straightforward way of analysing intermolecular interactions in the crystal environment. The use of atomic Hirshfeld surfaces has also demonstrated that such surfaces carry information related to chemical bonds which allow a deeper evaluation of the structures. Here we briefly summarize the approach of atomic Hirshfeld surfaces while further evaluating the kind of information that can be retrieved from them. We show that the analysis of the metal-centre Hirshfeld surfaces from structures refined via Hirshfeld Atom Refinement (HAR) allow accurate evaluation of contacts of type M⋯H, and that such contacts can be related to the overall shape of the surfaces. The compounds analysed were tetraaquabis(3-carboxypropionato)metal(II), [M(C4H3O4)2(H2O)4], for metal(II)/M = manganese/Mn, cobalt/Co, nickel/Ni and zinc/Zn. We also evaluate the sensitivity of the surfaces by an investigation of seemingly flat surfaces through analysis of the curvature functions in the direction of C—C bonds. The obtained values not only demonstrate variations in curvature but also show a correlation with the hybridization of the C atoms involved in the bond. Full Article text
irs Transferable Hirshfeld atom model for rapid evaluation of aspherical atomic form factors By journals.iucr.org Published On :: 2024-03-01 Form factors based on aspherical models of atomic electron density have brought great improvement in the accuracies of hydrogen atom parameters derived from X-ray crystal structure refinement. Today, two main groups of such models are available, the banks of transferable atomic densities parametrized using the Hansen–Coppens multipole model which allows for rapid evaluation of atomic form factors and Hirshfeld atom refinement (HAR)-related methods which are usually more accurate but also slower. In this work, a model that combines the ideas utilized in the two approaches is tested. It uses atomic electron densities based on Hirshfeld partitions of electron densities, which are precalculated and stored in a databank. This model was also applied during the refinement of the structures of five small molecules. A comparison of the resulting hydrogen atom parameters with those derived from neutron diffraction data indicates that they are more accurate than those obtained with the Hansen–Coppens based databank, and only slightly less accurate than those obtained with a version of HAR that neglects the crystal environment. The advantage of using HAR becomes more noticeable when the effects of the environment are included. To speed up calculations, atomic densities were represented by multipole expansion with spherical harmonics up to l = 7, which used numerical radial functions (a different approach to that applied in the Hansen–Coppens model). Calculations of atomic form factors for the small protein crambin (at 0.73 Å resolution) took only 68 s using 12 CPU cores. Full Article text
irs Hirshfeld atom refinement and dynamical refinement of hexagonal ice structure from electron diffraction data By journals.iucr.org Published On :: 2024-07-30 Reaching beyond the commonly used spherical atomic electron density model allows one to greatly improve the accuracy of hydrogen atom structural parameters derived from X-ray data. However, the effects of atomic asphericity are less explored for electron diffraction data. In this work, Hirshfeld atom refinement (HAR), a method that uses an accurate description of electron density by quantum mechanical calculation for a system of interest, was applied for the first time to the kinematical refinement of electron diffraction data. This approach was applied here to derive the structure of ordinary hexagonal ice (Ih). The effect of introducing HAR is much less noticeable than in the case of X-ray refinement and it is largely overshadowed by dynamical scattering effects. It led to only a slight change in the O—H bond lengths (shortening by 0.01 Å) compared with the independent atom model (IAM). The average absolute differences in O—H bond lengths between the kinematical refinements and the reference neutron structure were much larger: 0.044 for IAM and 0.046 Å for HAR. The refinement results changed considerably when dynamical scattering effects were modelled – with extinction correction or with dynamical refinement. The latter led to an improvement of the O—H bond length accuracy to 0.021 Å on average (with IAM refinement). Though there is a potential for deriving more accurate structures using HAR for electron diffraction, modelling of dynamical scattering effects seems to be a necessary step to achieve this. However, at present there is no software to support both HAR and dynamical refinement. Full Article text
irs 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
irs 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
irs 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
irs 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
irs 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
irs 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