ses BJP expresses concern over govt.’s ‘negligence’ towards health facilities By www.thehindu.com Published On :: Sun, 10 May 2020 02:32:57 +0530 ‘State government has failed to protect the people of Delhi from the virus’ Full Article Delhi
ses Coronavirus cases worldwide surpass 4 million By www.thehindu.com Published On :: Sun, 10 May 2020 06:49:19 +0530 The number of novel coronavirus cases recorded worldwide surpassed four million on Saturday, according to an AFP tally based on official sources, as o Full Article International
ses S. Korea reports 34 new coronavirus cases, highest in a month By www.thehindu.com Published On :: Sun, 10 May 2020 08:36:45 +0530 The outbreak came just as South Korea has eased some social distancing restrictions and is seeking to fully reopen schools and businesses Full Article International
ses Coronavirus India lockdown Day 47 updates | Death toll crosses 2,100 By www.thehindu.com Published On :: Sun, 10 May 2020 12:14:10 +0530 Globally, as of 9 May 2020, there have been 3,862,676 confirmed cases, including 265,961 deaths, reported to WHO. Full Article National
ses 12 rescued so far after portion of chawl collapses in Kandivali, NDRF called in By www.thehindu.com Published On :: Sun, 10 May 2020 11:22:37 +0530 Search and rescue operations are still under way, incident escalated to a Level II emergency Full Article Mumbai
ses Tamil Nadu forms high level committee to assess Covid-19 impact on economy By www.business-standard.com Published On :: Sat, 09 May 2020 19:07:00 +0530 The committee shall submit its final reports to the government within three months time and also submit an interim report Full Article
ses Hyderabad: Birthday party trigger for 45 coronavirus cases in LB Nagar By timesofindia.indiatimes.com Published On :: Sun, 10 May 2020 06:03:38 IST Full Article
ses Covid19: TN eases lockdown restrictions even as 526 more active cases reported in last 24 hours By www.thehindubusinessline.com Published On :: Sat, 09 May 2020 20:21:05 +0530 Another 279 patients in Chennai, taking the tally to 3,330 Full Article News
ses Covid-19 in India: Death toll rises to 2,109; cases climb to 62,939 By www.thehindubusinessline.com Published On :: Sun, 10 May 2020 11:07:19 +0530 Maharashtra tops the tally with 779 deaths Full Article News
ses Mumbai: Several trapped after building collapses in Kandivali West; rescue operation underway By www.dnaindia.com Published On :: Sun, 10 May 2020 03:16:00 GMT Further details are awaited. Full Article India
ses COVID-19: Return of Bundesliga in fresh jeopardy as Dynamo Dresden confirms two new coronavirus cases ahead of restart By www.dnaindia.com Published On :: Sun, 10 May 2020 03:59:00 GMT The Bundesliga and Bundesliga 2 are set to be back underway on May 16. Full Article Sports
ses Ahmedabad Covid-19 cases now 5,540; toll 363 By timesofindia.indiatimes.com Published On :: Sat, 09 May 2020 22:55:48 IST Full Article
ses How starving horses found love and a meal By www.rediff.com Published On :: Sun, 10 May 2020 10:48:32 +0530 The horses on Chennai's Marina beach were slowly starving to death because of the lockdown until Shiranee Pereira decided to take a hand. Full Article
ses 128 Covid deaths, 3,277 cases in 24 hrs; toll 2,109 By www.rediff.com Published On :: Sun, 10 May 2020 12:20:36 +0530 Of the 2,109 fatalities, Maharashtra tops the tally with 779 deaths. Gujarat comes second with 472 deaths, followed by Madhya Pradesh at 215, West Bengal at 171, Rajasthan at 106, Uttar Pradesh at 74, Delhi at 73, and Andhra Pradesh and Tamil Nadu at 44. Full Article
ses Rock ‘n’ roll pioneer Little Richard passes away By indianexpress.com Published On :: Sat, 09 May 2020 14:35:59 +0000 Full Article Entertainment Pop/Bollywood Music
ses Chandigarh: Bapu dham resident tests positive after death, UT sees 21 new cases By indianexpress.com Published On :: Sat, 09 May 2020 20:40:20 +0000 Full Article Chandigarh Cities
ses Random sampling finds two positive cases in two days in Panchkula By indianexpress.com Published On :: Sat, 09 May 2020 20:43:31 +0000 Full Article Chandigarh Cities
ses Punjab and Haryana HC to hold 10 benches for hearing of urgent cases over video conferencing By indianexpress.com Published On :: Sun, 10 May 2020 03:44:56 +0000 Full Article Chandigarh Cities
ses Plea in Punjab and Haryana HC seeks directions to health facilities to attend non-Covid cases By indianexpress.com Published On :: Sun, 10 May 2020 05:00:50 +0000 Full Article Chandigarh Cities
ses 31 new Covid-19 cases in Punjab, total 1,762 By timesofindia.indiatimes.com Published On :: Sat, 09 May 2020 23:18:44 IST Full Article
ses 28 cases take Haryana's corona tally to 675 By timesofindia.indiatimes.com Published On :: Sat, 09 May 2020 20:41:56 IST The Covid-19 count of Haryana on Saturday reached 675 as 28 new cases, which includes 25 from the national capital region (NCR) were reported. A 22-year-old TB patient also succumbed to Covid-19 in Panipat taking death toll to 9 in the state. Full Article
ses Banned Umar Akmal refuses to divulge details of two meetings with suspected bookies: PCB sources By indianexpress.com Published On :: Sun, 10 May 2020 06:25:20 +0000 Full Article Cricket Sports
ses X-ray reflecto-interferometer based on compound refractive lenses By scripts.iucr.org Published On :: 2019-08-12 An X-ray amplitude-splitting interferometer based on compound refractive lenses, which operates in the reflection mode, is proposed and realized. The idea of a reflecto-interferometer is to use a very simplified experimental setup where a focused X-ray beam reflected from parallel flat surfaces creates an interference pattern in a wide angular range. The functional capabilities of the interferometer were experimentally tested at the European Synchrotron Radiation Facility (ESRF) ID06 beamline in the X-ray energy range from 10 keV to 15 keV. The main features of the proposed approach, high spatial and temporal resolution, were demonstrated experimentally. The reflections from free-standing Si3N4 membranes, gold and resist layers were studied. Experimentally recorded interferograms are in good agreement with our simulations. The main advantages and future possible applications of the reflecto-interferometer are discussed. Full Article text
ses Generating three-color pulses in high-gain harmonic-generation free-electron lasers with a tilted electron bunch By scripts.iucr.org Published On :: 2019-08-12 A multi-color light source is a significant tool for nonlinear optics experiments, pump–dump/repump–probe experiments and in other fields. Here, a novel method is proposed to create three-color pulses based on a high-gain harmonic-generation (HGHG) free-electron laser with a tilted electron bunch. In this method, the initial bunch tilt is created by transverse wakefields after the bunch passes through a corrugated structure with an off-axis orbit, and is further enlarged in a following drift section. Then the tilted bunch experiences the off-axis field of a quadrupole magnet to cool down the large transverse velocity induced before. After that, it enters an HGHG configuration adopting a transverse gradient undulator (TGU) as the radiator, where only three separated fractions of the tilted bunch will resonate at three adjacent harmonics of the seed wavelength and are enabled to emit three-color pulses simultaneously. In addition, the use of the natural transverse gradient of a normal planar undulator instead of the TGU radiator to emit three-color pulses is also studied in detail. Numerical simulations including the generation of the tilted bunch and the free-electron laser radiation confirm the validity and feasibility of this scheme both for the TGU radiator and the natural gradient in the extreme-ultraviolet waveband. Full Article text
ses Viruses and viral proteins By journals.iucr.org Published On :: The X-ray structures of viruses and viral proteins currently available are providing high-resolution snapshots of viral molecular machineries, expanding our vision of the virus world and giving crucial information on potential targets for future antiviral therapies. Full Article text
ses Structure and function of dioxygenases in histone demethylation and DNA/RNA demethylation By journals.iucr.org Published On :: The structure and function of dioxygenases in histone demethylation and DNA/RNA dimethylation are discussed. Full Article text
ses Kent earthquake 'causes homes to shake' - BBC News By www.bbc.co.uk Published On :: Fri, 22 May 2015 07:00:00 GMT Kent earthquake 'causes homes to shake' BBC News Full Article
ses Compasses at Greenwich Are About to Do Something Not Observed in Over 300 Years - ScienceAlert By www.sciencealert.com Published On :: Mon, 02 Sep 2019 07:00:00 GMT Compasses at Greenwich Are About to Do Something Not Observed in Over 300 Years ScienceAlert Full Article
ses Houses 'rattled' as minor earthquakes shake Shropshire - BBC News By www.bbc.co.uk Published On :: Tue, 15 Oct 2019 07:00:00 GMT Houses 'rattled' as minor earthquakes shake Shropshire BBC News Full Article
ses Earth scientists plan to meld massive databases into a 'geological Google' - Science Magazine By www.sciencemag.org Published On :: Tue, 26 Feb 2019 08:00:00 GMT Earth scientists plan to meld massive databases into a 'geological Google' Science Magazine Full Article
ses Bond-valence analyses of the crystal structures of FeMo/V cofactors in FeMo/V proteins By journals.iucr.org Published On :: The bond-valence method was performed on 51 crystal data sets from nitrogenase proteins, indicating the presence of molybdenum(III) in FeMo cofactors and vanadium(III) with more reduced iron complements in FeV cofactors. Full Article text
ses Crystal structure of bis(1-ethyl-1H-imidazole-κN3)(meso-tetramesitylporphyrinato-κ4N,N',N'',N''')iron(III) perchlorate chlorobenzene sesquisolvate By scripts.iucr.org Published On :: 2019-05-31 In the complex cation of title compound, [Fe(C56H52N4)(C5H8N2)2]ClO4·1.5C6H5Cl, the ironIII atom is coordinated in a distorted octahedral manner by four pyrrole N atoms of the porphyrin ring system in the equatorial plane, and by two N atoms of the 1-ethylimidazole ligands in the axial sites. A disordered perchlorate anion and one and a half chlorobenzene solvent molecules are also present. The cationic complex exhibits a highly ruffled porphyrin core. The average Fe—Np (Np is a porphyrin N atom) bond length is 1.988 (5), and the axial Fe—NIm (NIm is an imidazole N atom) bond lengths are 1.962 (3) and 1.976 (3) Å. The two 1-ethylimidazole ligands are inclined to each other by a dihedral angle of 68.62 (16)°. The dihedral angles between the 1-ethylimidazole planes and the planes of the closest Fe—Np vector are 28.52 (18) and 43.57 (13)°. Intermolecular C—H⋯Cl interactions are observed. Full Article text
ses Bis(μ2-4-nitrophenolato)bis(4-nitrophenolato)di-μ3-oxido-octaphenyltetratin chloroform sesquisolvate [+ solvate]: a tetranuclear stannoxane By scripts.iucr.org Published On :: 2019-08-06 The title tetranuclear stannoxane, [Sn4(C6H5)8(C6H4NO3)4O2]·1.5CHCl3·solvent, crystallized with two independent complex molecules, A and B, in the asymmetric unit together with 1.5 molecules of chloroform. There is also a region of disordered electron density, which was corrected for using the SQUEEZE routine [Spek (2015). Acta Cryst. C71, 9–18]. The oxo-tin core of each complex is in a planar `ladder' arrangement and each Sn atom is fivefold SnO3C2 coordinated, with one tin centre having an almost perfect square-pyramidal coordination geometry, while the other three Sn centres have distorted shapes. In the crystal, the complex molecules are arranged in layers, composed of A or B complexes, lying parallel to the bc plane. The complex molecules are linked by a number of C—H⋯O hydrogen bonds within the layers and between the layers, forming a supramolecular three-dimensional structure. Full Article text
ses Crystal structures and Hirshfeld surface analyses of 4,4'-{[1,3-phenylenebis(methylene)]bis(oxy)}bis(3-methoxybenzaldehyde) and 4,4'-{[(1,4-phenylenebis(methylene)]bis(oxy)}bis( By scripts.iucr.org Published On :: 2019-05-24 The title compounds, C24H22O6 (I) and C24H22O6 (II), each crystallize with half a molecule in the asymmetric unit. The whole molecule of compound (I) is generated by twofold rotation symmetry, the twofold axis bisecting the central benzene ring. The whole molecule of compound (II) is generated by inversion symmetry, the central benzene ring being located on an inversion center. In (I), the outer benzene rings are inclined to each other by 59.96 (10)° and by 36.74 (9)° to the central benzene ring. The corresponding dihedral angles in (II) are 0.0 and 89.87 (12)°. In the crystal of (I), molecules are linked by C—H⋯O hydrogen bonds and C—H⋯π interactions, forming ribbons propagating along the [10overline{1}] direction. In the crystal of (II), molecules are linked by C—H⋯O hydrogen bonds, forming a supramolecular framework. The Hirshfeld surface analyses indicate that for both compounds the H⋯H contacts are the most significant, followed by O⋯H/H⋯O and C⋯H/H⋯C contacts. Full Article text
ses Syntheses, crystal structures, and comparisons of rare-earth oxyapatites Ca2RE8(SiO4)6O2 (RE = La, Nd, Sm, Eu, or Yb) and NaLa9(SiO4)6O2 By scripts.iucr.org Published On :: 2019-06-21 Six different rare-earth oxyapatites, including Ca2RE8(SiO4)6O2 (RE = La, Nd, Sm, Eu, or Yb) and NaLa9(SiO4)6O2, were synthesized using solution-based processes followed by cold pressing and sintering. The crystal structures of the synthesized oxyapatites were determined from powder X-ray diffraction (P-XRD) and their chemistries verified with electron probe microanalysis (EPMA). All the oxyapatites were isostructural within the hexagonal space group P63/m and showed similar unit-cell parameters. The isolated [SiO4]4− tetrahedra in each crystal are linked by the cations at the 4f and 6h sites occupied by RE3+ and Ca2+ in Ca2RE8(SiO4)6O2 or La3+ and Na+ in NaLa9(SiO4)6O2. The lattice parameters, cell volumes, and densities of the synthesized oxyapatites fit well to the trendlines calculated from literature values. Full Article text
ses Syntheses, crystal structures and Hirshfeld surface analyses of (3aR,4S,7R,7aS)-2-(perfluoropyridin-4-yl)-3a,4,7,7a-tetrahydro-4,7-methanoisoindole-1,3-dione and (3aR,4S,7R,7aS)-2-[(perfluoropyridin-4-yl)oxy]-3a,4,7,7a- By scripts.iucr.org Published On :: 2019-07-12 The syntheses and crystal structures of the title compounds, C14H8F4N2O2 and C14H8F4N2O3, are reported. In each crystal, the packing is driven by C—H⋯F intertactions, along with a variety of C—H⋯O, C—O⋯π, and C—F⋯π contacts. Hirshfeld surface analysis was conducted to aid in the visualization of these various influences on the packing: they showed that the largest contributions to the surface contacts arise from H⋯F/F⋯H interactions, followed by H⋯H and O⋯H/H⋯O. Full Article text
ses Crystal structures and Hirshfeld surface analyses of the two isotypic compounds (E)-1-(4-bromophenyl)-2-[2,2-dichloro-1-(4-nitrophenyl)ethenyl]diazene and (E)-1-(4-chlorophenyl)-2-[2,2-dichloro-1-(4-ni By scripts.iucr.org Published On :: 2019-07-19 In the two isotypic title compounds, C14H8BrCl2N3O2, (I), and C14H8Cl3N3O2, (II), the substitution of one of the phenyl rings is different [Br for (I) and Cl for (II)]. Aromatic rings form dihedral angles of 60.9 (2) and 64.1 (2)°, respectively. Molecules are linked through weak X⋯Cl contacts [X = Br for (I) and Cl for (II)], C—H⋯Cl and C—Cl⋯π interactions into sheets parallel to the ab plane. Additional van der Waals interactions consolidate the three-dimensional packing. Hirshfeld surface analysis of the crystal structures indicates that the most important contributions for the crystal packing for (I) are from C⋯H/H⋯C (16.1%), O⋯H/H⋯O (13.1%), Cl⋯H/H⋯Cl (12.7%), H⋯H (11.4%), Br⋯H/H⋯Br (8.9%), N⋯H/H⋯N (6.9%) and Cl⋯C/C⋯Cl (6.6%) interactions, and for (II), from Cl⋯H / H⋯Cl (21.9%), C⋯H/H⋯C (15.3%), O⋯H/H⋯O (13.4%), H⋯H (11.5%), Cl⋯C/C⋯Cl (8.3%), N⋯H/H⋯N (7.0%) and Cl⋯Cl (5.9%) interactions. The crystal of (I) studied was refined as an inversion twin, the ratio of components being 0.9917 (12):0.0083 (12). Full Article text
ses Syntheses and crystal structures of a new family of hybrid perovskites: C5H14N2·ABr3·0.5H2O (A = K, Rb, Cs) By scripts.iucr.org Published On :: 2019-07-26 The syntheses and crystal structures of three hybrid perovskites, viz. poly[1-methylpiperizine-1,4-diium [tri-μ-bromido-potassium] hemihydrate], {(C5H14N2)[KBr3]·0.5H2O}n, (I), poly[1-methylpiperizine-1,4-diium [tri-μ-bromido-rubidium] hemihydrate], {(C5H14N2)[RbBr3]·0.5H2O}n, (II), and poly[1-methylpiperizine-1,4-diium [tri-μ-bromido-caesium] hemihydrate], {(C5H14N2)[CsBr3]·0.5H2O}n, (III), are described. These isostructural (space group Amm2) phases contain a three-dimensional, corner-sharing network of distorted ABr6 octahedra (A = K, Rb, Cs) with the same topology as the classical perovskite structure. The doubly protonated C5H14N22+ cations occupy interstices bounded by eight octahedra and the water molecules lie in square sites bounded by four octahedra. N—H⋯Br, N—H⋯(Br,Br), N—H⋯O and O—H⋯Br hydrogen bonds consolidate the structures. Full Article text
ses Syntheses and structures of piperazin-1-ium ABr2 (A = Cs or Rb): hybrid solids containing `curtain wall' layers of face- and edge-sharing ABr6 trigonal prisms By scripts.iucr.org Published On :: 2019-07-26 The isostructural title compounds, poly[piperazin-1-ium [di-μ-bromido-caesium]], {(C4H11N2)[CsBr2]}n, and poly[piperazin-1-ium [di-μ-bromido-rubidium]], {(C4H11N2)[RbBr2]}n, contain singly-protonated piperazin-1-ium cations and unusual ABr6 (A = Cs or Rb) trigonal prisms. The prisms are linked into a distinctive `curtain wall' arrangement propagating in the (010) plane by face and edge sharing. In each case, a network of N—H⋯N, N—H⋯Br and N—H⋯(Br,Br) hydrogen bonds consolidates the structure. Full Article text
ses Syntheses and crystal structures of 2-methyl-1,1,2,3,3-pentaphenyl-2-silapropane and 2-methyl-1,1,3,3-tetraphenyl-2-silapropan-2-ol By scripts.iucr.org Published On :: 2019-08-23 The sterically hindered silicon compound 2-methyl-1,1,2,3,3-pentaphenyl-2-silapropane, C33H30Si (I), was prepared via the reaction of two equivalents of diphenylmethyllithium (benzhydryllithium) and dichloromethylphenylsilane. This bisbenzhydryl-substituted silicon compound was then reacted with trifluoromethanesulfonic acid, followed by hydrolysis with water to give the silanol 2-methyl-1,1,3,3-tetraphenyl-2-silapropan-2-ol, C27H26OSi (II). Key geometric features for I are the Si—C bond lengths that range from 1.867 (2) to 1.914 (2) Å and a τ4 descriptor for fourfold coordination around the Si atom of 0.97 (indicating a nearly perfect tetrahedron). Key geometric features for compound II include Si—C bond lengths that range from 1.835 (4) to 1.905 (3) Å, a Si—O bond length of 1.665 (3) Å, and a τ4 descriptor for fourfold coordination around the Si atom of 0.96. In compound II, there is an intramolecular C—H⋯O hydrogen bond present. In the crystal of I, molecules are linked by two pairs of C—H⋯π interactions, forming dimers that are linked into ribbons propagating along the b-axis direction. In the crystal of II, molecules are linked by C—H⋯π and O—H⋯π interactions that result in the formation of ribbons that run along the a-axis direction. Full Article text
ses The crystal structures and Hirshfeld surface analyses of four 3,5-diacetyl-2-methyl-2,3-dihydro-1,3,4-thiadiazol-2-yl derivatives By scripts.iucr.org Published On :: 2019-09-10 The title compounds, 4-(5-acetamido-3-acetyl-2-methyl-2,3-dihydro-1,3,4-thiadiazol-2-yl)phenyl benzoate, C20H19N3O4S (I), 4-(5-acetamido-3-acetyl-2-methyl-2,3-dihydro-1,3,4-thiadiazol-2-yl)phenyl isobutyrate 0.25-hydrate, C17H21N3O4S·0.25H2O (II), 4-(5-acetamido-3-acetyl-2-methyl-2,3-dihydro-1,3,4-thiadiazol-2-yl)phenyl propionate, C16H19N3O4S (III) and 4-(5-acetamido-3-acetyl-2-methyl-2,3-dihydro-1,3,4-thiadiazol-2-yl)phenyl cinnamate chloroform hemisolvate, C22H21N3O4S·0.5CHCl3 (IV), all crystallize with two independent molecules (A and B) in the asymmetric unit in the triclinic Poverline{1} space group. Compound II crystallizes as a quaterhydrate, while compound IV crystallizes as a chloroform hemisolvate. In compounds I, II, III (molecules A and B) and IV (molecule A) the five-membered thiadiazole ring adopts an envelope conformation, with the tetrasubstituted C atom as the flap. In molecule B of IV this ring is flat (r.m.s. deviation 0.044 Å). The central benzene ring is in general almost normal to the mean plane of the thiadiazole ring in each molecule, with dihedral angles ranging from 75.8 (1) to 85.5 (2)°. In the crystals of all four compounds, the A and B molecules are linked via strong N—H⋯O hydrogen bonds and generate centrosymmetric four-membered R44(28) ring motifs. There are C—H⋯O hydrogen bonds present in the crystals of all four compounds, and in I and II there are also C—H⋯π interactions present. The intermolecular contacts in the crystals of all four compounds were analysed using Hirshfeld surface analysis and two-dimensional fingerprint plots. Full Article text
ses Crystal structures and Hirshfeld surface analyses of (E)-N'-benzylidene-2-oxo-2H-chromene-3-carbohydrazide and the disordered hemi-DMSO solvate of (E)-2-oxo-N'-(3,4,5-trimethoxybenzylidene)-2H-chromene-3-carbohydrazide: lattice ene By scripts.iucr.org Published On :: 2019-09-03 The crystal structures of the disordered hemi-DMSO solvate of (E)-2-oxo-N'-(3,4,5-trimethoxybenzylidene)-2H-chromene-3-carbohydrazide, C20H18N2O6·0.5C2H6OS, and (E)-N'-benzylidene-2-oxo-2H-chromene-3-carbohydrazide, C17H12N2O3 (4: R = C6H5), are discussed. The non-hydrogen atoms in compound [4: R = (3,4,5-MeO)3C6H2)] exhibit a distinct curvature, while those in compound, (4: R = C6H5), are essential coplanar. In (4: R = C6H5), C—H⋯O and π–π intramolecular interactions combine to form a three-dimensional array. A three-dimensional array is also found for the hemi-DMSO solvate of [4: R = (3,4,5-MeO)3C6H2], in which the molecules of coumarin are linked by C—H⋯O and C—H⋯π interactions, and form tubes into which the DMSO molecules are cocooned. Hirshfeld surface analyses of both compounds are reported, as are the lattice energy and intermolecular interaction energy calculations of compound (4: R = C6H5). Full Article text
ses Crystal structures, syntheses, and spectroscopic and electrochemical measurements of two push–pull chromophores: 2-[4-(dimethylamino)benzylidene]-1H-indene-1,3(2H)-dione and (E)-2-{3-[4-(dimethylamino)phenyl By scripts.iucr.org Published On :: 2019-10-03 The title pull–push chromophores, 2-[4-(dimethylamino)benzylidene]-1H-indene-1,3(2H)-dione, C18H15NO2 (ID[1]) and (E)-2-{3-[4-(dimethylamino)phenyl]allylidene}-1H-indene-1,3(2H)-dione, C20H17NO2 (ID[2]), have donor–π-bridge–acceptor structures. The molecule with the short π-bridge, ID[1], is almost planar while for the molecule with a longer bridge, ID[2], is less planar. The benzene ring is inclined to the mean plane of the 2,3-dihydro-1H-indene unit by 3.19 (4)° in ID[1] and 13.06 (8)° in ID[2]. The structures of three polymorphs of compound ID[1] have been reported: the α-polymorph [space group P21/c; Magomedova & Zvonkova (1978). Kristallografiya, 23, 281–288], the β-polymorph [space group P21/c; Magomedova & Zvonkova (1980). Kristallografiya, 25 1183–1187] and the γ-polymorph [space group Pna21; Magomedova, Neigauz, Zvonkova & Novakovskaya (1980). Kristallografiya, 25, 400–402]. The molecular packing in ID[1] studied here is centrosymmetric (space group P21/c) and corresponds to the β-polymorph structure. The molecular packing in ID[2] is non-centrosymmetric (space group P21), which suggests potential NLO properties for this crystalline material. In both compounds, there is short intramolecular C—H⋯O contact present, enclosing an S(7) ring motif. In the crystal of ID[1], molecules are linked by C—H⋯O hydrogen bonds and C—H⋯π interactions, forming layers parallel to the bc plane. In the crystal of ID[2], molecules are liked by C—H⋯O hydrogen bonds to form 21 helices propagating along the b-axis direction. The molecules in the helix are linked by offset π–π interactions with, for example, a centroid–centroid distance of 3.9664 (13) Å (= b axis) separating the indene rings, and an offset of 1.869 Å. Spectroscopic and electrochemical measurements show the ability of these compounds to easily transfer electrons through the π-conjugated chain. Full Article text
ses Tetra-n-butylammonium orotate monohydrate: knowledge-based comparison of the results of accurate and lower-resolution analyses and a non-routine disorder refinement By scripts.iucr.org Published On :: 2019-10-08 The title hydrated molecular salt (systematic name: tetra-n-butylammonium 2,6-dioxo-1,2,3,6-tetrahydropyrimidine-4-carboxylate monohydrate), C16H36N+·C5H3N2O4−·H2O, crystallizes with N—H⋯O and O—H⋯O hydrogen-bonded double-stranded antiparallel ribbons consisting of the hydrophilic orotate monoanions and water molecules, separated by the bulky hydrophobic cations. The hydrophobic and hydrophilic regions of the structure are joined by weaker non-classical C—H⋯O hydrogen bonds. An accurate structure analysis conducted at T = 100 K is compared to a lower-resolution less accurate determination using data measured at T = 295 K. The results of both analyses are evaluated using a knowledge-based approach, and it is found that the less accurate room-temperature structure analysis provides geometric data that are similar to those derived from the accurate low-temperature analysis, with both sets of results consistent with previously analyzed structures. A minor disorder of one methyl group in the cation at low temperature was found to be slightly more complex at room temperature; while still involving a minor fraction of the structure, the disorder at room temperature was found to require a non-routine treatment, which is described in detail. Full Article text
ses Crystal structures and Hirshfeld surface analyses of 4-benzyl-6-phenyl-4,5-dihydropyridazin-3(2H)-one and methyl 2-[5-(2,6-dichlorobenzyl)-6-oxo-3-phenyl-1,4,5,6-tetrahydropyridazin-1-yl]acetate By scripts.iucr.org Published On :: 2019-10-22 The asymmetric units of the title compounds both contain one nonplanar molecule. In 4-benzyl-6-phenyl-4,5-dihydropyridazin-3(2H)-one, C17H14N2O, (I), the phenyl and pyridazine rings are twisted with respect to each other, making a dihedral angle of 46.69 (9)°; the phenyl ring of the benzyl group is nearly perpendicular to the plane of the pyridazine ring, the dihedral angle being 78.31 (10)°. In methyl 2-[5-(2,6-dichlorobenzyl)-6-oxo-3-phenyl-1,4,5,6-tetrahydropyridazin-1-yl]acetate, C20H16Cl2N2O3, (II), the phenyl and pyridazine rings are twisted with respect to each other, making a dihedral angle of 21.76 (18)°, whereas the phenyl ring of the dichlorobenzyl group is inclined to the pyridazine ring by 79.61 (19)°. In the crystal structure of (I), pairs of N—H⋯O hydrogen bonds link the molecules into inversion dimers with an R22(8) ring motif. In the crystal structure of (II), C—H⋯O hydrogen bonds generate dimers with R12(7), R22(16) and R22(18) ring motifs. The Hirshfeld surface analyses of compound (I) suggests that the most significant contributions to the crystal packing are by H⋯H (48.2%), C⋯H/H⋯C (29.9%) and O⋯H/H⋯O (8.9%) contacts. For compound (II), H⋯H (34.4%), C⋯H/H⋯C (21.3%) and O⋯H/H⋯O (16.5%) interactions are the most important contributions. Full Article text
ses Crystal structures and Hirshfeld surface analyses of (E)-N'-benzylidene-2-oxo-2H-chromene-3-carbohydrazide and the disordered hemi-DMSO solvate of (E)-2-oxo-N'-(3,4,5-trimethoxybenzylidene)-2H-chromene-3-carbohydrazide: lattice ene By scripts.iucr.org Published On :: 2019-11-29 In the paper by Gomes et al. [Acta Cryst. (2019), E75, 1403–1410], there was an error and omission in the author and affiliation list. Full Article text
ses Syntheses and crystal structures of three [M(acac)2(TMEDA)] complexes (M = Mn, Fe and Zn) By scripts.iucr.org Published On :: 2020-01-01 The complexes bis(acetylacetonato-κ2O,O')(N,N,N',N'-tetramethylethylenediamine-κ2N,N')manganese(II), [Mn(C5H7O2)2(C6H16N2)], bis(acetylacetonato-κ2O,O')(N,N,N',N'-tetramethylethylenediamine-κ2N,N')iron(II), [Fe(C5H7O2)2(C6H16N2)], and bis(acetylacetonato-κ2O,O')(N,N,N',N'-tetramethylethylenediamine-κ2N,N')zinc(II), [Zn(C5H7O2)2(C6H16N2)], were synthesized from the reaction of the corresponding metal acetylacetonates [M(acac)2(H2O)2] with N,N,N',N'-tetramethylethylenediamine (TMEDA) in toluene. Each of the complexes displays a central metal atom which is nearly octahedrally surrounded by two chelating acac and one chelating TMEDA ligand, resulting in an N2O4 coordination set. Despite the chemical similarity of the complex units, the packing patterns for compounds 1–3 are different and thus the crystal structures are not isotypic. Full Article text
ses Syntheses and crystal structures of 2,2,5-trimethyl-1,3-dioxane-5-carboxylic acid and 2,2,5-trimethyl-1,3-dioxane-5-carboxylic anhydride By scripts.iucr.org Published On :: 2020-01-01 In 2,2,5-trimethyl-1,3-dioxane-5-carboxylic acid, C8H14O4, the carboxyl group occupies an equatorial position on the 1,3-dioxane ring. In the crystal, O—H⋯O hydrogen bonds form chains of molecules, which are linked into a three-dimensional network by C—H⋯O hydrogen bonds. The asymmetric unit of 2,2,5-trimethyl-1,3-dioxane-5-carboxylic anhydride, C16H26O7, consists of two independent molecules, which are linked by C—H⋯O hydrogen bonds. In the crystal, these units are connected into corrugated layers two molecules thick and parallel to the ab plane by additional C—H⋯O hydrogen bonds. Full Article text
ses The crystal structures and Hirshfeld surface analyses of a cadmium(II) and a zinc(II) mononuclear complex of the new tetrakis-substituted pyrazine ligand N,N',N'',N'''-[pyrazine-2,3,5,6-tetrayltetrakis(methylene)]tetrakis By scripts.iucr.org Published On :: 2020-02-18 The whole molecule of the cadmium(II) complex, diiodido{N,N',N'',N'''-[pyrazine-2,3,5,6-tetrayltetrakis(methylene)]tetrakis(N-methylaniline)-κ3N2,N1,N6}cadmium(II), [CdI2(C36H40N6)], (I), of the ligand N,N',N'',N'''-[pyrazine-2,3,5,6-tetrayltetrakis(methylene)]tetrakis(N-methylaniline) (L), is generated by a twofold rotation symmetry; the twofold axis bisects the cadmium atom and the nitrogen atoms of the pyrazine ring. The ligand coordinates in a mono-tridentate manner and the cadmium atom has a fivefold CdN3I2 coordination environment with a distorted shape. In the zinc(II) complex, dichlorido{N,N',N'',N'''-[pyrazine-2,3,5,6-tetrayltetrakis(methylene)]tetrakis(N-methylaniline)-κ3N2,N1,N6}zinc(II) dichloromethane 0.6-solvate, [ZnCl2(C36H40N6)]·0.6CH2Cl2, (II), ligand L also coordinates in a mono-tridentate manner and the zinc atom has a fivefold ZnN3Cl2 coordination environment with a distorted shape. It crystallized as a partial dichloromethane solvate. In the crystal of I, the complex molecules are linked by weak C—H⋯I contacts, forming ribbons propagating along [100]. In the crystal of II, the complex molecules are linked by a series of C—H⋯π interactions, forming layers lying parallel to the (1overline{1}1) plane. In the crystals of both compounds there are metal–halide⋯π(pyrazine) contacts present. The Hirshfeld analyses confirm the importance of the C—H⋯halide contacts in the crystal packing of both compounds. Full Article text
ses Syntheses and crystal structures of a new pyrazine dicarboxamide ligand, N2,N3-bis(quinolin-8-yl)pyrazine-2,3-dicarboxamide, and of a copper perchlorate binuclear complex By scripts.iucr.org Published On :: 2020-02-14 The title pyrazine dicarboxamide ligand, N2,N3-bis(quinolin-8-yl)pyrazine-2,3-dicarboxamide (H2L1), C24H16N6O2, has a twisted conformation with the outer quinoline groups being inclined to the central pyrazine ring by 9.00 (6) and 78.67 (5)°, and by 79.94 (4)° to each other. In the crystal, molecules are linked by C—H⋯O hydrogen bonds, forming layers parallel to the (10overline{1}) plane, which are in turn linked by offset π–π interactions [intercentroid distances 3.4779 (9) and 3.6526 (8) Å], forming a supramolecular three-dimensional structure. Reaction of the ligand H2L1 with Cu(ClO4)2 in acetonitrile leads to the formation of the binuclear complex, [μ-(3-{hydroxy[(quinolin-8-yl)imino]methyl}pyrazin-2-yl)[(quinolin-8-yl)imino]methanolato]bis[diacetonitrilecopper(II)] tris(perchlorate) acetonitrile disolvate, [Cu2(C24H15N6O2)(CH3CN)4](ClO4)3·2CH3CN or [Cu2(HL1−)(CH3CN)4](ClO4)3·2CH3CN (I). In the cation of complex I, the ligand coordinates to the copper(II) atoms in a bis-tridentate fashion. A resonance-assisted O—H⋯O hydrogen bond is present in the ligand; the position of this H atom was located in a difference-Fourier map. Both copper(II) atoms are fivefold coordinate, being ligated by three N atoms of the ligand and by the N atoms of two acetonitrile molecules. The first copper atom has a perfect square-pyramidal geometry while the second copper atom has a distorted shape. In the crystal, the cation and perchlorate anions are linked by a number of C—H⋯O hydrogen bonds, forming a supramolecular three-dimensional structure. Full Article text