assistplus will be rolled out at a health care centre in Malappuram by June

Officials told to prepare for the monsoon

The antigen test is the third type of test to be authorized by the FDA.

‘State government has failed to protect the people of Delhi from the virus’

Sara Ali Khan shared a beautiful picture of Amrita Singh and Rukhsana Sultana holding her newborn self

According to a report by security agencies, the presence of around 450 terrorists, including those from Lashkar-e-Taiba (LeT), Hizbul Mujahideen (HM) and Jaish-e-Mohammad (JeM), has been seen on the launching pads adjacent to the Line of Control (LoC).

'I'm excited to get back in, I really do miss it. This has been almost a blessing on one side because it gives you more appreciation for the things that you love and do.'

A new method based on time-resolved X-ray diffraction is proposed in order to measure the elastic strain and stress during ultrasonic fatigue loading experiments. Pure Cu was chosen as an example material for the experiments using a 20 kHz ultrasonic fatigue machine mounted on the six-circle diffractometer available at the DiffAbs beamline on the SOLEIL synchrotron facility in France. A two-dimensional hybrid pixel X-ray detector (XPAD3.2) was triggered by the strain gage signal in a synchronous data acquisition scheme (pump–probe-like). The method enables studying loading cycles with a period of 50 µs, achieving a temporal resolution of 1 µs. This allows a precise reconstruction of the diffraction patterns during the loading cycles. From the diffraction patterns, the position of the peaks, their shifts and their respective broadening can be deduced. The diffraction peak shift allows the elastic lattice strain to be estimated with a resolution of ∼10−5. Stress is calculated by the self-consistent scale-transition model through which the elastic response of the material is estimated. The amplitudes of the cyclic stresses range from 40 to 120 MPa and vary linearly with respect to the displacement applied by the ultrasonic machine. Moreover, the experimental results highlight an increase of the diffraction peak broadening with the number of applied cycles.

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.

Calibration of area detectors from powder diffraction standards is widely used at synchrotron beamlines. From a single diffraction image, it is not possible to determine both the sample-to-detector distance and the wavelength, but, with images taken from multiple positions along the beam direction and where the relative displacement is known, the sample-to-detector distance and wavelength can both be determined with good precision. An example calibration using the GSAS-II software package is presented.

Multilayer monochromator devices are commonly used at (imaging) beamlines of synchrotron facilities to shape the X-ray beam to relatively small bandwidth and high intensity. However, stripe artefacts are often observed and can deteriorate the image quality. Although the intensity distribution of these artefacts has been described in the literature, their spectral distribution is currently unknown. To assess the spatio-spectral properties of the monochromated X-ray beam, the direct beam has been measured for the first time using a hyperspectral X-ray detector. The results show a large number of spectral features with different spatial distributions for a [Ru, B4C] strip monochromator, associated primarily with the higher-order harmonics of the undulator and monochromator. It is found that their relative contributions are sufficiently low to avoid an influence on the imaging data. The [V, B4C] strip suppresses these high-order harmonics even more than the former, yet at the cost of reduced efficiency.

A novel sample cell with control of temperature and relative humidity permitted collection of data of excellent quality, enabling unrestrained refinement of all atomic parameters. One of the K atoms in the structure is disordered; very strong anisotropy in three of the four water O atoms indicates partial static disorder, which does not involve the bonded H atoms.

Ripon sinkhole concerns halt Harrogate council homes plans  BBC News

Biggest tremor on record at Little Plumpton site forces halt to fracking in Lancashire  Lancashire Evening Post

Two earthquakes felt by residents in Lochaber  Press and Journal

Did the quake shake you? Earth tremor felt in Shropshire  shropshirestar.com

'Rumbling' felt during Ardnamurchan earthquake  BBC News

Reports of an earthquake felt in Leicestershire | Central - ITV News  ITV News

Did the earth move for you? British Geological Survey has asked if Cumbrians felt an earth tremor last week  News & Star

A new scaling program is presented with new features to support multi-sweep workflows and analysis within the DIALS software package.

The title compound, [Co(NCS)2(C15H22N2O2)2] or C32H44CoN6O4S2, was prepared from cobalt(II) nitrate, benzyl carbazate and ammonium thio­cyanate in the presence of 4-hepta­none. The compound crystallizes with two centrosymmetric complexes in which the cobalt(II) atoms have a trans-CoO2N4 octa­hedral coordination geometry. In the crystal, N—H⋯S, C—H⋯S and C—H⋯.π contacts stack the complex mol­ecules along the b-axis direction.

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.

The title compound, d-(+)-glucosa­mmonium potassium tetra­thio­cyanato­cobaltate(II) dihydrate, K(C6H14NO5)[Co(NCS)4]·2H2O or (GlcNH)(K)[Co(NCS)4]·2H2O, has been obtained as a side product of an incomplete salt metathesis reaction of d-(+)-glucosa­mine hydro­chloride (GlcN·HCl) and K2[Co(NCS)4]. The asymmetric unit contains a d-(+)-glucos­ammonium cation, a potassium cation, a tetra­iso­thio­cyanato­cobalt(II) complex anion and two water mol­ecules. The water mol­ecules coordinate to the potassium cation, which is further coordinated via three short K+⋯SCN− contacts involving three [Co(NCS)4]2− complex anions and via three O atoms of two d-(+)-glucosa­mmonium cations, leading to an overall eightfold coordination around the potassium cation. Hydrogen-bonding inter­actions between the building blocks consolidate the three-dimensional arrangement.

The title compound, [Co(C18H37N2)2(NCS)4], consists of a cobalt(II) ion positioned on the origin of the triclinic unit cell. It is coordinated by the N atoms of two trans-oriented 1-dodecyl-4-aza-1-azoniabi­cyclo­[2.2.2]octane (DABCO+) cations, which carry n-dodecyl chains at the non-coordinating N atoms. The distorted octa­hedral coordination environment of the CoII ion is completed through four N atoms of iso­thio­cyanate ions, which are arranged within the equatorial plane. Non-classical hydrogen bonding of the types C—H⋯N and C—H⋯S between the filamentous mol­ecules lead to the formation of layers parallel to (001).

The title compound {systematic name: N-[2-(5-meth­oxy-1H-indol-3-yl)eth­yl]-N-(prop-2-en-1-yl)prop-2-en-1-amine), C17H22N2O, has a single tryptamine mol­ecule in the asymmetric unit. The mol­ecules are linked by strong N—H⋯N hydrogen bonds into zigzag chains with graph-set notation C(7) along the [010] direction.

The title compound (systematic name: bis­{2-[4-(acet­yloxy)-1H-indol-3-yl]ethan-1-aminium} but-2-enedioate), 2C14H19N2O2+·C4H2O42−, has a single protonated psilacetin cation and one half of a fumarate dianion in the asymmetric unit. There are N—H⋯O hydrogen bonds between the ammonium H atoms and the fumarate O atoms, as well as N—H⋯O hydrogen bonds between the indole H atoms and the fumarate O atoms. The hydrogen bonds hold the ions together in infinite one-dimensional chains along [111].

In the title compound, the asymmetric unit comprises an N,N,N-trimethyl-1-(4-vinyl­phen­yl)methanaminium cation and a 4-vinyl­benzene­sulfonate anion, C12H18N+·C8H7O3S−. The salt has a polymerizable vinyl group attached to both the cation and the anion. The methanaminium and vinyl substituents on the benzene ring of the cation subtend angles of 86.6 (3) and 10.5 (9)° to the ring plane, while the anion is planar excluding the sulfonate O atoms. The vinyl substituent on the benzene ring of the cation is disordered over two sites with a refined occupancy ratio of 0.542 (11):0.458 (11). In the crystal, C—H⋯O hydrogen bonds dominate the packing and combine with a C—H⋯π(ring) contact to stack the cations and anions along the a-axis direction. Hirshfeld surface analysis of the salt and of the individual cation and anion components is also reported.

The title compound, C12H21NO7, (I), is conformationally unstable; the predominant form present in its solution is the β-pyran­ose form (74.3%), followed by the β- and α-furan­oses (12.1 and 10.2%, respectively), α-pyran­ose (3.4%), and traces of the acyclic carbohydrate tautomer. In the crystalline state, the carbohydrate part of (I) adopts the 2C5 β-pyran­ose conformation, and the amino acid portion exists as a zwitterion, with the side chain cyclo­pentane ring assuming the E9 envelope conformation. All heteroatoms are involved in hydrogen bonding that forms a system of anti­parallel infinite chains of fused R33(6) and R33(8) rings. The mol­ecule features extensive intra­molecular hydrogen bonding, which is uniquely multicentered and involves the carboxyl­ate, ammonium and carbohydrate hy­droxy groups. In contrast, the contribution of inter­molecular O⋯H/H⋯O contacts to the Hirshfeld surface is relatively low (38.4%), as compared to structures of other d-fructose-amino acids. The 1H NMR data suggest a slow rotation around the C1—C2 bond in (I), indicating that the intra­molecular heteroatom contacts survive in aqueous solution of the mol­ecule as well.

The title hydrated salt, tris­[hexa­amminecobalt(III)] tetraoxidorhenate(VII) tetra­kis­[hexa­fluorido­rhenate(IV)] hexa­hydrate, arose unexpectedly due to possible contamination of the K2ReF6 starting material with KReO4. It consists of octa­hedral [Co(NH3)6]3+ cation (Co1 site symmetry 1), tetra­hedral [ReVIIO4]− anions (Re site symmetry 1) and octa­hedral [ReIVF6]2− anions (Re site symmetries 1and overline{3}). The [ReF6]2− octa­hedral anions (mean Re—F = 1.834 Å), [Co(NH3)6]3+ octa­hedral cations (mean Co—N = 1.962 Å), and the [ReO4]− tetra­hedral anion (mean Re—O = 1.719 Å) are slightly distorted. A network of N—H⋯F hydrogen bonds consolidates the structure. The crystal studied was refined as a two-component twin.

The monocation product of the oxidative condensation–cyclization between two mol­ecules of pyridine-2-carbaldehyde and one mol­ecule of CH3NH2·HCl in methanol, 2-methyl-3-(pyridin-2-yl)imidazo[1,5-a]pyridinium, was isolated in the presence of metal ions as bis­[2-methyl-3-(pyridin-2-yl)imidazo[1,5-a]pyridin-2-ium] tetra­iodo­cadmate, (C13H12N3)2[CdI4], (I), and the mixed chloride/nitrate salt, bis­[2-methyl-3-(pyridin-2-yl)imidazo[1,5-a]pyridin-2-ium] 1.5-chlor­ide 0.5-nitrate trihydrate, 2C13H12N3+·1.5Cl−·0.5NO3−·3H2O, (II). Hybrid salt (I) crystallizes in the space group P21/n with two [L]2[CdI4] mol­ecules in the asymmetric unit related by pseudosymmetry. In the crystal of (I), layers of organic cations and of tetra­halometallate anions are stacked parallel to the ab plane. Anti­parallel L+ cations disposed in a herring-bone pattern form π-bonded chains through aromatic stacking. In the inorganic layer, adjacent tetra­hedral CdI4 units have no connectivity but demonstrate close packing of iodide anions. In the crystal lattice of (II), the cations are arranged in stacks propagating along the a axis; the one-dimensional hydrogen-bonded polymer built of chloride ions and water mol­ecules runs parallel to a column of stacked cations.

The synthesis and structural characterization of the mol­ecular compound (μ3-benzene-1,2-di­thiol­ato)hexa­carbonyl­bis­(μ3-1,1,1,4,4,4-hexafluorobut-2-ene-2,3-dithiolato)tricobaltmolybdenum, [Co3Mo(C4F6S2)2(C6H4S2)(CO)6] or Mo(tfd)2(bdt)(Co(CO)2)3 (tfd is 1,1,1,4,4,4-hexafluorobut-2-ene-2,3-dithiolate and bdt is benzene-1,2-di­thiol­ate), are reported. The structure of the mol­ecule contains the molybdenum tris­(di­thiol­ene) complex Mo(tfd)2(bdt) coordinated as a multidentate ligand to three cobalt dicarbonyl units. Each of the three cobalt centers is relatively close to molybdenum, with Co⋯Mo distances of 2.7224 (7), 2.8058 (7), and 2.6320 (6) Å. Additionally, each of the cobalt centers is bound via main-group donor atoms, but each one in a different way: the first cobalt atom is coordinated by two sulfur atoms from different di­thiol­enes (bdt and tfd). The second cobalt atom is coordinated by one sulfur from one tfd and two olefinic carbons from another tfd. The third cobalt is coordinated by one sulfur from bdt and two sulfurs from tfd. This is, to the best of our knowledge, the first structurally characterized example of a molybdenum (tris­)di­thiol­ene complex that coordinates to cobalt. The F atoms of two of the –CF3 groups were refined as disordered over two sets of sites with ratios of refined occupancies of 0.703 (7):0.297 (7) and 0.72 (2):0.28 (2).

The solid-state structures of the salts of two substituted tryptamines, namely N-isopropyl-N-methyl­tryptaminium (MiPT) fumarate {systematic name: [2-(1H-indol-3-yl)eth­yl](meth­yl)propan-2-yl­aza­nium 3-carb­oxy­prop-2-enoate}, C14H21N2+·C4H3O4−, and 4-hy­droxy-N-isopropyl-N-methyl­tryptaminium (4-HO-MiPT) fumarate monohydrate {systematic name: [2-(4-hy­droxy-1H-indol-3-yl)eth­yl](meth­yl)propan-2-yl­aza­nium 3-carb­oxy­prop-2-enoate monohydrate}, C14H21N2O+·C4H3O4−·H2O, are reported. Both salts possess a proton­ated tryptammonium cation and a 3-carb­oxy­acrylate (hydrogen fumarate) anion in the asymmetric unit; the 4-HO-MiPT structure also contains a water mol­ecule of crystallization. Both cations feature disorder of the side chain over two orientations, in a 0.630 (3):0.370 (3) ratio for MiPT and a 0.775 (5):0.225 (5) ratio for 4-HO-MiPT. In both extended structures, N—H⋯O and O—H⋯O hydrogen bonds generate infinite two-dimensional networks.

The title salt, C10H21N2O+·C7H12NO4S−, comprises a 3-methacryl­amido-N,N,N-tri­methyl­propan-1-aminium cation and a 2-acryl­amido-2-methyl­propane-1-sulfonate anion. The salt crystallizes with two unique cation–anion pairs in the asymmetric unit of the ortho­rhom­bic unit cell. The crystal studied was an inversion twin with a 0.52 (4):0.48 (4) domain ratio. In the crystal, the cations and anions stack along the b-axis direction and are linked by an extensive series of N—H⋯O and C—H⋯O hydrogen bonds, forming a three-dimensional network. Hirshfeld surface analysis was carried out on both the asymmetric unit and the two individual salts. The contribution of inter­atomic contacts to the surfaces of the individual cations and anions are also compared.

Twelve 4-(4-meth­oxy­phen­yl)piperazin-1-ium salts containing organic anions have been prepared and structurally characterized. The monohydrated benzoate, 4-fluoro­benzoate, 4-chloro­benzoate and 4-bromo­benzoate salts, C11H17N2O+·C7H5O2−·H2O (I), C11H17N2O+·C7H4FO2−·H2O (II), C11H17N2O+·C7H4ClO2−·H2O (III), and C11H17N2O+·C7H4BrO2−·H2O (IV), respectively, are isomorphous and all exhibit disorder in the 4-meth­oxy­phenyl unit: the components are linked by N—H⋯O and O—H⋯O hydrogen bond to form chains of rings. The unsolvated 2-hy­droxy­benzoate, pyridine-3-carboxyl­ate and 2-hy­droxy-3,5-di­nitro­benzoate salts, C11H17N2O+·C7H5O3− (V), C11H17N2O+·C6H4NO2− (VI) and C11H17N2O+·C7H3N2O7− (VII), respectively, are all fully ordered: the components of (V) are linked by multiple N—H⋯O hydrogen bonds to form a chain of rings; those of (VI) are linked into a three-dimensional framework by a combination of N—H⋯O, C—H⋯O and C—H⋯N hydrogen bonds and those of (VII), where the anion has a structure reminiscent of the picrate anion, are linked into a three-dimensional array by N—H⋯O and C—H⋯O hydrogen bonds. The hydrogensuccinate and hydrogenfumarate salts, C11H17N2O+·C4H5O4− (VIII) and C11H17N2O+·C4H3O3− (IX), respectively, are isomorphous, and both exhibit disorder in the anionic component: N—H⋯O and O—H⋯O hydrogen bonds link the ions into sheets, which are further linked by C—H⋯π(arene) inter­actions. The anion of the hydrogenmaleate salt, C11H17N2O+·C4H3O3− (X), contains a very short and nearly symmetrical O⋯H⋯O hydrogen bond, and N—H⋯O hydrogen bonds link the anions into chains of rings. The ions in the tri­chloro­acetate salt, C11H17N2O+·C2Cl3O2− (XI), are linked into simple chains by N—H⋯O hydrogen bonds. In the hydrated chloranilate salt, 2C11H17N2O+·C6Cl2O42−·2H2O (XII), which crystallizes as a non-merohedral twin, the anion lies across a centre of inversion in space group P21/n, and a combination of N—H⋯O and O—H⋯O hydrogen bonds generates complex sheets. Comparisons are made with the structures of some related compounds.

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.

Charge-assisted hydrogen bonding plays a significant role in the crystal structures of solvates of ionic com­pounds, especially when the cation or cations are primary ammonium salts. We report the crystal structures of four ammonium salts of molybdenum halide cluster solvates where we observe significant hydrogen bonding between the solvent molecules and cations. The crystal structures of bis­(anilinium) octa-μ3-chlorido-hexa­chlorido-octa­hedro-hexa­molybdate N,N-di­­methyl­formamide tetra­solvate, (C6H8N)2[Mo6Cl8Cl6]·4C3H7NO, (I), p-phenyl­enedi­ammonium octa-μ3-chlorido-hexa­chlorido-octa­hedro-hexa­mol­yb­date N,N-di­methyl­formamide hexa­solvate, (C6H10N2)[Mo6Cl8Cl6]·6C3H7NO, (II), N,N'-(1,4-phenyl­ene)bis­(propan-2-iminium) octa-μ3-chlorido-hexa­chlo­rido-octa­hedro-hexa­molybdate acetone tris­olvate, (C12H18N2)[Mo6Cl8Cl6]·3C3H6O, (III), and 1,1'-dimethyl-4,4'-bipyridinium octa-μ3-chlo­rido-hexa­chlorido-octa­hedro-hexa­molybdate N,N-di­methyl­formamide tetra­solvate, (C12H14N2)[Mo6Cl8Cl6]·4C3H7NO, (IV), are reported and described. In (I), the anilinium cations and N,N-di­methyl­formamide (DMF) solvent mol­ecules form a cyclic R42(8) hydrogen-bonded motif centered on a crystallographic inversion center with an additional DMF mol­ecule forming a D(2) inter­action. The p-phenyl­enedi­ammonium cation in (II) forms three D(2) inter­actions between the three N—H bonds and three independent N,N-di­methyl­formamide mol­ecules. The dication in (III) is a protonated Schiff base solvated by acetone mol­ecules. Compound (IV) contains a methyl viologen dication with N,N-di­methyl­formamide mol­ecules forming close contacts with both aromatic and methyl H atoms.

A reaction of copper(II) carbonate and potassium 4-sulfo­benzoic acid in water acidified with hydro­chloric acid yielded two crystalline products. Tetra­aqua­bis­(4-carb­oxy­benzene­sulfonato)­copper(II) dihydrate, [Cu(O3SC6H4CO2H)2(H2O)4]·2H2O, (I), crystallizes in the triclinic space group Poverline{1} with the Cu2+ ions located on centers of inversion. Each copper ion is coordinated to four water mol­ecules in a square plane with two sulfonate O atoms in the apical positions of a Jahn–Teller-distorted octa­hedron. The carboxyl­ate group is protonated and not involved in coordination to the metal ions. The complexes pack so as to create a layered structure with alternating inorganic and organic domains. The packing is reinforced by several O—H⋯O hydrogen bonds involving coordinated and non-coordinated water mol­ecules, the carb­oxy­lic acid group and the sulfonate group. Hexa­aqua­copper(II) 4-carb­oxy­benzene­sulfonate, [Cu(H2O)6](O3SC6H4CO2H)2, (II), also crystallizes in the triclinic space group Poverline{1} with Jahn–Teller-distorted octa­hedral copper(II) aqua complexes on the centers of inversion. As in (I), the carboxyl­ate group on the anion is protonated and the structure consists of alternating layers of inorganic cations and organic anions linked by O—H⋯O hydrogen bonds. A reaction of silver nitrate and potassium 4-sulfo­benzoic acid in water also resulted in two distinct products that have been structurally characterized. An anhydrous silver potassium 4-carb­oxy­benzene­sulfonate salt, [Ag0.69K0.31](O3SC6H4CO2H), (III), crystallizes in the monoclinic space group C2/c. There are two independent metal sites, one fully occupied by silver ions and the other showing a 62% K+/38% Ag+ (fixed) ratio, refined in two slightly different positions. The coordination environments of the metal ions are composed primarily of sulfonate O atoms, with some participation by the non-protonated carboxyl­ate O atoms in the disordered site. As in the copper compounds, the cations and anions cleanly segregate into alternating layers. A hydrated mixed silver potassium 4-carb­oxy­benzene­sulfonate salt dihydrate, [Ag0.20K0.80](O3SC6H4CO2H)·2H2O, (IV), crystallizes in the monoclinic space group P21/c with the Ag+ and K+ ions sharing one unique metal site coordinated by two water mol­ecules and six sulfonate O atoms. The packing in (IV) follows the dominant motif of alternating inorganic and organic layers. The protonated carboxyl­ate groups do not inter­act with the cations directly, but do participate in hydrogen bonds with the coordinated water mol­ecules. (IV) is isostructural with pure potassium 4-sulfo­benzoic acid dihydrate.

The solid-state structures of two cobalt–pyridine–sulfate compounds, namely catena-poly[[tetra­kis­(pyridine-κN)cobalt(II)]-μ-sulfato-κ2O:O'], [Co(SO4)(C5H5N)4]n, (1), and catena-poly[[tetra­kis­(pyridine-κN)cobalt(II)]-μ-sulfato-κ3O:O',O''-[bis­(pyridine-κN)cobalt(II)]-μ-sulfato-κ3O,O':O'']n, [Co2(SO4)2(C5H5N)6]n, (2), are reported. Compound (1) displays a polymeric structure, with infinite chains of CoII cations adopting octa­hedral N4O2 coordination environments that involve four pyridine ligands and two bridging sulfate ions. Compound (2) is also polymeric with infinite chains of CoII cations. The first Co center has an octa­hedral N4O2 coordination environment that involves four pyridine ligands and two bridging sulfate ligands. The second Co center has an octa­hedral N2O4 coordination environment that involves two pyridine ligands and two bridging sulfate ions that chelate the Co atom. The structure of (2) was refined as a two-component inversion twin.

The title homoleptic Schiff base complexes, [M(C14H9Cl2N2O)2], for M = CoII, (I), and CuII, (II), present distinct coordination geometries despite the Schiff base dianion coordinating via the phenolato-O and imine-N atoms in each case. For (I), the coordination geometry is based on a trigonal bipyramid whereas for (II), a square-planar geometry is found (Cu site symmetry overline{1}). In the crystal of (I), discernible supra­molecular layers in the ac plane are sustained by chloro­benzene-C—H⋯O(coordinated), chloro­benzene-C—H⋯π(fused-benzene ring) as well as π(fused-benzene, chloro­benzene)–π(chloro­benzene) inter­actions [inter-centroid separations = 3.6460 (17) and 3.6580 (16) Å, respectively]. The layers inter-digitate along the b-axis direction and are linked by di­chloro­benzene-C—H⋯π(fused-benzene ring) and π–π inter­actions between fused-benzene rings and between chloro­benzene rings [inter-centroid separations = 3.6916 (16) and 3.7968 (19) Å, respectively] . Flat, supra­molecular layers are also found in the crystal of (II), being stabilized by π–π inter­actions formed between fused-benzene rings and between chloro­benzene rings [inter-centroid separations = 3.8889 (15) and 3.8889 (15) Å, respectively]; these stack parallel to [10overline{1}] without directional inter­actions between them. The analysis of the respective calculated Hirshfeld surfaces indicate diminished roles for H⋯H contacts [26.2% (I) and 30.5% (II)] owing to significant contributions by Cl⋯H/H⋯Cl contacts [25.8% (I) and 24.9% (II)]. Minor contributions by Cl⋯Cl [2.2%] and Cu⋯Cl [1.9%] contacts are indicated in the crystals of (I) and (II), respectively. The inter­action energies largely arise from dispersion terms; the aforementioned Cu⋯Cl contact in (II) gives rise to the most stabilizing inter­action in the crystal of (II).

The title compound [systematic name: (1R*, 8S)-2-acetamidoocta­hydro­pyrrol­izin-4-ium chloride–N-[(1R, 8S)-hexa­hydro-1H-pyrrolizin-2-yl)acetamide (1/1)], 2(C9H16N2O)·HCl or C9H17N2O+·Cl−·C9H16N2O, arose as an unexpected product when 1-exo-acetamido­pyrrolizidine (AcAP; C9H16N2O) was dissolved in CHCl3. Within the AcAP pyrrolizidine group, the unsubstituted five-membered ring is disordered over two orientations in a 0.897 (5):0.103 (5) ratio. Two AcAP mol­ecules related by a crystallographic twofold axis link to H+ and Cl− ions lying on the rotation axis, thereby forming N—H⋯N and N—H⋯Cl⋯H—N hydrogen bonds. The first of these has an unusually short N⋯N separation of 2.616 (2) Å: refinement of different models against the present data set could not distinguish between a symmetrical hydrogen bond (H atom lying on the twofold axis and equidistant from the N atoms) or static or dynamic disorder models (i.e. N—H⋯N + N⋯H—N). Computational studies suggest that the disorder model is slightly more stable, but the energy difference is very small.