Lockdown effect: Retailers eye renegotiating contracts at malls

The Regional Science Centre & Planetarium, Kozhikode, is organising “Online Summer Hobby Camp 2020” for students of Classes 7 to 10 from May 18. T

Gadkari also assured the retailers of looking into their demands of financial aid from the government

This will reduce crowding at the market at Mattuthavani

A new Rococo 2 X-ray fluorescence detector was implemented into the cryogenic sample environment at the Hard X-ray Micro/Nano-Probe beamline P06 at PETRA III, DESY, Hamburg, Germany. A four sensor-field cloverleaf design is optimized for the investigation of planar samples and operates in a backscattering geometry resulting in a large solid angle of up to 1.1 steradian. The detector, coupled with the Xspress 3 pulse processor, enables measurements at high count rates of up to 106 counts per second per sensor. The measured energy resolution of ∼129 eV (Mn Kα at 10000 counts s−1) is only minimally impaired at the highest count rates. The resulting high detection sensitivity allows for an accurate determination of trace element distributions such as in thin frozen hydrated biological specimens. First proof-of-principle measurements using continuous-movement 2D scans of frozen hydrated HeLa cells as a model system are reported to demonstrate the potential of the new detection system.

PLEASE REDUCE TO 1-2 SENTENCES. The capability of X-ray diffraction for the microstructure investigations of metastable systems is illustrated on the example of thin films of titanium aluminium nitrides with high aluminium content, which are supersaturated and partially decomposed. In addition to the chemical composition, the surface mobility of the deposited species was employed as a factor influencing the microstructure of the thin films. It is shown how the micromechanical properties of the partially decomposed (Ti,Al)N thin films, which were deduced from the synchrotron diffraction experiments, are related to the thin film microstructure and to the decomposition mechanism. The prominent role of the crystallographic anisotropy of the macroscopic and microscopic lattice deformations in the understanding of the micromechanical properties is addressed.

The title compound, [Ag2(C2H3O2)2(C19H20N2)2] (2), was readily synthesized by treatment of 3-benzyl-1-(2,4,6-tri­methyl­phen­yl)imidazolium chloride with silver acetate. The solution structure of the complex was analyzed by NMR spectroscopy, while the solid-state structure was confirmed by single-crystal X-ray diffraction studies. Compound 2 crystallizes in the triclinic space group Poverline{1}, with a silver-to-carbene bond length (Ag—CNHC) of 2.084 (3) Å. The mol­ecule resides on an inversion center, so that only half of the mol­ecule is crystallographically unique. The planes defined by the two imidazole rings are parallel to each other, but not coplanar [inter­planar distance is 0.662 (19) Å]. The dihedral angles between the imidazole ring and the benzyl and mesityl rings are 77.87 (12) and 72.86 (11)°, respectively. The crystal structure features π–π stacking inter­actions between the benzylic groups of inversion-related (−x + 1, −y + 1, −z + 1) mol­ecules and C—H⋯π inter­actions.

An aluminium-deficient Al8Cr5-type inter­metallic with formula Al7.85Cr5.16 (octa­aluminium penta­chromium) was uncovered when high-pressure sinter­ing of a mixture with composition Al11Cr4 was carried out. Structure analysis reveals that there are three co-occupied positions with refined occupancy factors for Al atoms being 0.958, 0.772 and 1/2. The present phase is confirmed to be isotypic with the previously reported rhombohedral Al8Cr5 ordered phase [Bradley & Lu (1937). Z. Kristallogr. 96, 20–37] and structurally closely related to the disordered phases of rhombohedral Al16Cr9.5 and cubic Al8Cr5.

The title compound, C9H11NO2, was obtained as unexpected product from the reaction of (4-{2-benz­yloxy-5-[(E)-(3-chloro-4-methyl­phen­yl)diazen­yl]benzyl­idene}-2-phenyl­oxazol-5(4H)-one) with 2-meth­oxy­aniline in the presence of acetic acid as solvent. The amide group is not coplanar with the benzene ring, as shown by the C—N—C—O and C—N—C—C torsion angles of −2.5 (3) and 176.54 (19)°, respectively. Hirshfeld surface analysis and two-dimensional fingerprint plots indicate that the most important contributions to the crystal packing are from H⋯H (53.9%), C⋯H/H⋯C (21.4%), O⋯H/H⋯O (21.4%) and N⋯H/H⋯N (1.7%) inter­actions.

The title pyridazinone derivative, C21H19ClN2O3, is not planar. The unsubstituted phenyl ring and the pyridazine ring are inclined to each other, making a dihedral angle of 17.41 (13)° whereas the Cl-substituted phenyl ring is nearly orthogonal to the pyridazine ring [88.19 (13)°]. In the crystal, C—H⋯O hydrogen bonds generate dimers with R22(10) and R22(24) ring motifs which are linked by C—H⋯O inter­actions, forming chains extending parallel to the c-axis direction. The inter­molecular inter­actions were investigated using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing that the most significant contributions to the crystal packing are from H⋯H (44.5%), C⋯H/H⋯C (18.5%), H⋯O/H⋯O (15.6%), Cl⋯H/H⋯Cl (10.6%) and C⋯C (2.8%) contacts.

From solutions of prehnitene and the ternary halides (SnCl)[MCl4] (M = Al, Ga) in chloro­benzene, the new cationic SnII–π-arene complexes catena-poly[[chlorido­aluminate(III)]-tri-μ-chlorido-4':1κ2Cl,1:2κ4Cl-[(η6-1,2,3,4-tetra­meth­yl­benzene)­tin(II)]-di-μ-chlorido-2:3κ4Cl-[(η6-1,2,3,4-tetra­methyl­benzene)­tin(II)]-di-μ-chlorido-3:4κ4Cl-[chlorido­aluminate(III)]-μ-chlorido-4:1'κ2Cl], [Al2Sn2Cl10(C10H14)2]n, (1) and catena-poly[[chlorido­gallate(III)]-tri-μ-chlor­ido-4':1κ2Cl,1:2κ4Cl-[(η6-1,2,3,4-tetra­methyl­benzene)­tin(II)]-di-μ-chlorido-2:3κ4Cl-[(η6-1,2,3,4-tetra­methyl­benzene)­tin(II)]-di-μ-chlorido-3:4κ4Cl-[chlor­ido­gallate(III)]-μ-chlorido-4:1'κ2Cl], [Ga2Sn2Cl10(C10H14)2]n, (2), were isolated. In these first main-group metal–prehnitene complexes, the distorted η6 arene π-bonding to the tin atoms of the Sn2Cl22+ moieties in the centre of [{1,2,3,4-(CH3)4C6H2}2Sn2Cl2][MCl4]2 repeating units (site symmetry overline{1}) is characterized by: (i) a significant ring slippage of ca 0.4 Å indicated by the dispersion of Sn—C distances [1: 2.881 (2)–3.216 (2) Å; 2: 2.891 (3)–3.214 (3) Å]; (ii) the non-methyl-substituted arene C atoms positioned closest to the SnII central atom; (iii) a pronounced tilt of the plane of the arene ligand against the plane of the central (Sn2Cl2)2+ four-membered ring species [1: 15.59 (11)°, 2: 15.69 (9)°]; (iv) metal–arene bonding of medium strength as illustrated by application of the bond-valence method in an indirect manner, defining the π-arene bonding inter­action of the SnII central atoms as s(SnII—arene) = 2 − Σs(SnII—Cl), that gives s(SnII—arene) = 0.37 and 0.38 valence units for the aluminate and the gallate, respectively, indicating that comparatively strong main-group metal–arene bonding is present and in line with the expectation that [AlCl4]− is the slightly weaker coordinating anion as compared to [GaCl4]−.

The title coordination polymer, {[Cu3(C4H4N3O9)3(SeO4)(OH)]·2H2O}n or ([Cu3(μ3-OH)(trgly)3(SeO4)]·2H2O), crystallizes in the monoclinic space group P21/c. The three independent Cu2+ cations adopt distorted square-pyramidal geometries with {O2N2+O} polyhedra. The three copper centres are bridged by a μ3-OH anion, leading to a triangular [Cu3(μ3-OH)] core. 2-(1,2,4-Triazol-4-yl)acetic acid (trgly-H) acts in a deprotonated form as a μ3-κ3N1:N2:O ligand. The three triazolyl groups bridge three copper centres of the hydroxo-cluster in an N1:N2 mode, thus supporting the triangular geometry. The [Cu3(μ3-OH)(tr)3] clusters serve as secondary building units (SBUs). Each SBU can be regarded as a six-connected node, which is linked to six neighbouring triangles through carboxyl­ate groups, generating a two-dimensional uninodal (3,6) coordination network. The selenate anion is bound in a μ3-κ3O1:O2:O3 fashion to the trinuclear copper platform. The [Cu3(OH)(trgly)3(SeO4)] coordination layers and guest water mol­ecules are linked together by numerous O—H⋯O and C—H⋯O hydrogen bonds, leading to a three-dimensional structure.

Three new isotypic heteropolynuclear complexes, namely penta­aqua­carbonato­penta­kis­(glycinehydroxamato)nitrato­penta­copper(II)lanthanide(III) x-hydrate, [LnCu5(GlyHA)5(CO3)(NO3)(H2O)5]·xH2O (GlyHA2− is glycine­hydrox­amate, N-hy­droxy­glycinamidate or amino­aceto­hydroxamate, C2H4N2O22−), with lanthanide(III) (LnIII) = gadolinium (Gd, 1, x = 3.5), dysprosium (Dy, 2, x = 3.28) and holmium (Ho, 3, x = 3.445), within a 15-metallacrown-5 class were obtained on reaction of lanthanide(III) nitrate, copper(II) acetate and sodium glycinehydroxamate. Complexes 1–3 contain five copper(II) ions and five bridging GlyHA2− anions, forming a [CuGlyHA]5 metallamacrocyclic core. The LnIII ions are coordinated to the metallamacrocycle through five O-donor hydroxamates. The electroneutrality of complexes 1–3 is achieved by a bidentate carbonate anion coordinated to the LnIII ion and a monodentate nitrate anion coordinated apically to one of the copper(II) ions of the metallamacrocycle. The lattice parameters of complexes 1–3 are similar to those previously reported for an EuIII–CuII 15-metallacrown-5 complex with glycine­hydroxamate of proposed composition [EuCu5(GlyHA)5(OH)(NO3)2(H2O)4]·3.5H2O [Stemmler et al. (1999). Inorg. Chem. 38, 2807–2817]. High-quality X-ray data obtained for 1–3 have allowed a re-evaluation of the X-ray data solution proposed earlier for the EuCu5 complex and suggest that the formula is actually [EuCu5(GlyHA)5(CO3)(NO3)(H2O)5]·3.5H2O.

The reaction of 2-methyl­thio-5-amino-1,3,4-thia­diazole (Me-SNTD; C3H5N3S2) with copper(II) acetate monohydrate [Cu(OAc)2·H2O; C4H8CuO5] resulted in the formation of the title binuclear compound, [Cu2(C2H3O2)4(C3H5N3S2)2] or [Cu2(OAc)4(Me-SNTD)2]. The structure has triclinic (P overline{1}) symmetry with a crystallographic inversion centre located at the midpoint of the line connecting the Cu atoms in the dimer. These two Cu atoms of the dimer [Cu⋯Cu = 2.6727 (6) Å] are held together by four carboxyl­ate groups. Each Cu atom is further coordinated to the N atom of an Me-SNTD mol­ecule and exhibits a Jahn–Teller-distorted octa­hedral geometry. The dimers are connected into infinite chains by hydrogen bonds between the NH (Me-SNTD) and the carboxyl­ate groups of neighbouring mol­ecules, generating an R22(12) ring motif. The mol­ecules are further linked by C—H⋯π inter­actions between the thia­diazole rings and the methyl groups of the acetate units.

Lapachol acetate [systematic name: 3-(3-methyl­but-2-en­yl)-1,4-dioxonaph­thalen-2-yl acetate], C17H16O4, was prepared using a modified high-yield procedure and its crystal structure is reported for the first time 80 years after its first synthesis. The full spectroscopic characterization of the mol­ecule is reported. The mol­ecular conformation shows little difference with other lapachol derivatives and lapachol itself. The packing is directed by inter­molecular π–π and C—H⋯O inter­actions, as described by Hirshfeld surface analysis. The former inter­actions make the largest contributions to the total packing energy in a ratio of 2:1 with respect to the latter.

The structure of the title compound, C32H51NO6, was determined from 62-year-old crystals at room temperature and refined with 100 K data in a monoclinic (C2) space group. This compound with a triterpenoid structure, now confirmed by this study, played an important role in the determination of the structure of lanosterol. The mol­ecules pack in linear O—H⋯O hydrogen-bonded chains along the short axis (b), while parallel chains display weak van der Waals inter­actions that explain the needle-shaped crystal morphology. The structure exhibits disorder of the flexible methyl­heptane chain at one end of the main mol­ecule with a small void around it. Crystals of the compounds were resistant to data collection for decades with the available cameras and Mo Kα radiation single-crystal diffractometer in our laboratory until a new instrument with Cu Kα radiation operating at 100 K allowed the structure to be solved and refined.

In the title compound, C16H14N2O3S, the 1,3-benzoxazole ring system is essentially planar (r.m.s deviation = 0.004 Å) and makes a dihedral angle of 66.16 (17)° with the benzene ring of the meth­oxy­phenyl group. Two intra­molecular N—H⋯O and N—H⋯N hydrogen bonds occur, forming S(5) and S(7) ring motifs, respectively. In the crystal, pairs of C—H⋯O hydrogen bonds link the mol­ecules into inversion dimers with R22(14) ring motifs, stacked along the b-axis direction. The inversion dimers are linked by C—H⋯π and π–π-stacking inter­actions [centroid-to-centroid distances = 3.631 (2) and 3.631 (2) Å], forming a three-dimensional network. Two-dimensional fingerprint plots associated with the Hirshfeld surface show that the largest contributions to the crystal packing come from H⋯H (39.3%), C⋯H/H⋯C (18.0%), O⋯H/H⋯O (15.6) and S⋯H/H⋯S (10.2%) inter­actions.

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.

In the crystal structures of the title com­pounds, namely μ-aqua-κ2O:O-di-μ-di­phenyl­acetato-κ4O:O'-bis­[(di­phenyl­acetato-κO)bis­(pyridine-κN)nickel(II)], [Ni2(C14H11O2)4(C5H5N)4(H2O)] (1) and μ-aqua-κ2O:O-di-μ-di­phenyl­acetato-κ4O:O'-bis­[(2,2'-bi­pyridine-κ2N,N')(di­phenyl­acetato-κO)nickel(II)]–aceto­nitrile–di­phenyl­acetic acid (1/2.5/1), [Ni2(C14H11O2)4(C10H8N2)2(H2O)]·2.5CH3CN·C14H12O2 (2), the com­plex units are stabilized by a variety of intra- and inter­molecular hydrogen bonds, as well as C—H⋯π and π–π contacts between the aromatic systems of the pyridine, dipyridyl and di­phenyl­acetate ligands. Despite the fact that the di­phenyl­acetate ligand is sterically bulky, this does not inter­fere with the formation of the described aqua-bridged dimeric core, even with a 2,2'-bi­pyridine ligand, which has a strong chelating effect.

The title com­pound, C24H24N2O6, consists of ethyl 2-(1,2,3,4-tetra­hydro-2-oxo­quinolin-1-yl)acetate and 4-[(2-eth­oxy-2-oxoeth­yl)(phen­yl)carbomoyl] units, where the oxo­quinoline unit is almost planar and the acetate substituent is nearly perpendicular to its mean plane. In the crystal, C—HOxqn⋯OEthx and C—HPh­yl⋯OCarbx (Oxqn = oxoquinolin, Ethx = eth­oxy, Phyl = phenyl and Carbx = carboxyl­ate) weak hydrogen bonds link the mol­ecules into a three-dimensional network sturucture. A π–π inter­action between the constituent rings of the oxo­quinoline unit, with a centroid–centroid distance of 3.675 (1) Å may further stabilize the structure. Both terminal ethyl groups are disordered over two sets of sites. The ratios of the refined occupanies are 0.821 (8):0.179 (8) and 0.651 (18):0.349 (18). The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (53.9%), H⋯O/O⋯H (28.5%) and H⋯C/C⋯H (11.8%) inter­actions. Weak inter­molecular hydrogen-bond inter­actions and van der Waals inter­actions are the dominant inter­actions in the crystal packing. Density functional theory (DFT) geometric optimized structures at the B3LYP/6-311G(d,p) level are com­pared with the experimentally determined mol­ecular structure in the solid state. The HOMO–LUMO mol­ecular orbital behaviour was elucidated to determine the energy gap.

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.

In the title compound, [Zn(C50H36N6O5)], the ZnII cation is chelated by four pyrrole N atoms of the porphyrinate anion and coordinated by a symmetry-generated keto O atom of the diazo­ester group in a distorted square-pyramidal geometry. The mean Zn—N(pyrrole) bond length is 2.058 Å and the Zn—O(diazo­ester) bond length is 2.179 (4) Å. The zinc cation is displaced by 0.2202 (13) Å from the N4C20 mean plane of the porphyrinate anion toward the O atom; the involvement of this atom leads to a [100] polymeric chain in the crystal.

The crystal structures of tris­[9,9-dihexyl-2-(5-meth­oxy­pyridin-2-yl-κN)-9H-fluoren-3-yl-κC3]iridium pentane monosolvate, [Ir(C31H38NO)3]·C5H12, (I), di-μ2-chlorido-bis­{bis­[2-(5-fluoro­pyridin-2-yl)-9,9-dihexyl-9H-fluoren-3-yl]iridium} pentane 0.3-solvate, [Ir2(C30H35FN)4Cl2]·0.3C5H12, (II), di-μ2-cyanato-bis­{bis­[9,9-dihexyl-2-(5-meth­oxy­pyridin-2-yl)-9H-fluoren-1-yl]iridium} pentane monosolvate, [Ir2(C31H38NO)4(NCO)2(NCO)2]·C5H12, (III), and {μ-N,N'-bis­[3,5-bis­(tri­fluoro­meth­yl)phen­yl]oxamidato}bis(bis{2-[4-(2,4,6-trimethylphenyl)pyridin-2-yl]phenyl-κ2C1,N'}iridium)–chloro­benzene–pentane (1/2.3/0.4), [Ir2(C20H19N)4(C18H6F12N2O2)]·2.3C6H5Cl·0.4C5H12, (IV), synthesized in the quest for organic light-emitting devices, were determined. The bis-μ2-chloro and bis-μ2-cyanato complexes have ΔΔ and ΛΛ configurations of the distorted octa­hedral Ir centres in racemic crystals, whereas the oxamido complex has a centrosymmetric (meso) structure with the ΔΛ configuration. The bridging oxamido moiety has a nearly planar anti geometry. All structures show substantial disorder of both host mol­ecules and solvents of crystallization.

The crystal structure of the polymeric title compound, catena-poly[[[di­aqua­lithium]-μ-γ-cyclo­dextrin(1−)-[aqua­lithium]-μ-γ-cyclo­dextrin(1−)] pentadecahydrate], {[Li2(C48H79O40)2(H2O)3]·15H2O}n, consists of deprotonated γ-cyclo­dextrin (CD) mol­ecules assembled by lithium ions into metal–organic ribbons that are cross-linked by multiple O—H⋯O hydrogen bonds into sheets extending parallel to (0overline11). Within a ribbon, one Li+ ion is coordinated by one deprotonated hydroxyl group of the first γ-CD torus and by one hydroxyl group of the second γ-CD torus as well as by two water mol­ecules. The other Li+ ion is coordinated by one deprotonated hydroxyl and by one hydroxyl group of the second γ-CD torus, by one hydroxyl group of the first γ-CD torus as well as by one water mol­ecule. The coordination spheres of both Li+ cations are distorted tetra­hedral. The packing of the structure constitute channels along the a axis. Parts of the hy­droxy­methyl groups in cyclo­dextrin molecules as well as water mol­ecules show two-component disorder. Electron density associated with additional disordered solvent mol­ecules inside the cavities was removed with the SQUEEZE [Spek (2015). Acta Cryst. C71, 9–18] routine in PLATON. These solvent mol­ecules are not considered in the given chemical formula and other crystal data. Five out of the sixteen hy­droxy­methyl groups and one water mol­ecule are disordered over two sets of sites.

In the title compound, C13H15N3O5S, the two rings face each other in a `V' form at the S atom, with one N—H⋯O=S and one C—H⋯O=S contact from the pyrazolyl substituents to the sulfonyl group. Two classical hydrogen bonds from the amine group, one of the form N—H⋯O=S and one N—H⋯O=Coxo, link the mol­ecules to form layers parallel to the bc plane.

In the title compound, C9H10ClNOS, the amide functional group –C(=O)NH– adopts a trans conformation with the four atoms nearly coplanar. This conformation promotes the formation of a C(4) hydrogen-bonded chain propagating along the [010] direction. The central part of the mol­ecule, including the six-membered ring, the S and N atoms, is fairly planar (r.m.s. deviation of 0.014). The terminal methyl group and the C(=O)CH2 group are slightly deviating out-of-plane while the terminal Cl atom is almost in-plane. Hirshfeld surface analysis of the title compound suggests that the most significant contacts in the crystal are H⋯H, H⋯Cl/Cl⋯H, H⋯C/C⋯H, H⋯O/O⋯H and H⋯S/S⋯H. π–π inter­actions between inversion-related mol­ecules also contribute to the crystal packing. DFT calculations have been performed to optimize the structure of the title compound using the CAM-B3LYP functional and the 6–311 G(d,p) basis set. The theoretical absorption spectrum of the title compound was calculated using the TD–DFT method. The analysis of frontier orbitals revealed that the π–π* electronic transition was the major contributor to the absorption peak in the electronic spectrum.

The title compound, C19H16ClNO3S, consists of chloro­phenyl methyl­idene and di­hydro­benzo­thia­zine units linked to an acetate moiety, where the thia­zine ring adopts a screw-boat conformation. In the crystal, two sets of weak C—HPh⋯ODbt (Ph = phenyl and Dbt = di­hydro­benzo­thia­zine) hydrogen bonds form layers of mol­ecules parallel to the bc plane. The layers stack along the a-axis direction with inter­calation of the ester chains. The crystal studied was a two component twin with a refined BASF of 0.34961 (5). The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions to the crystal packing are from H⋯H (37.5%), H⋯C/C⋯H (24.6%) and H⋯O/O⋯H (16.7%) inter­actions. Hydrogen-bonding and van der Waals inter­actions are the dominant inter­actions in the crystal packing. Computational chemistry indicates that in the crystal, C—HPh⋯ODbt hydrogen bond energies are 38.3 and 30.3 kJ mol−1. Density functional theory (DFT) optimized structures at the B3LYP/ 6–311 G(d,p) level are compared with the experimentally determined mol­ecular structure in the solid state. The HOMO–LUMO behaviour was elucidated to determine the energy gap. Moreover, the anti­bacterial activity of the title compound has been evaluated against gram-positive and gram-negative bacteria.

The title compound, C18H16N2O3S, was synthesized by reaction of 2-mercapto-3-phenyl­quinazolin-4(3H)-one with ethyl chloro­acetate. The quinazoline ring forms a dihedral angle of 86.83 (5)° with the phenyl ring. The terminal methyl group is disordered by a rotation of about 60° in a 0.531 (13): 0.469 (13) ratio. In the crystal, C—H⋯O hydrogen-bonding inter­actions result in the formation of columns running in the [010] direction. Two parallel columns further inter­act by C—H⋯O hydrogen bonds. The most important contributions to the surface contacts are from H⋯H (48.4%), C⋯H/H⋯C (21.5%) and O⋯H/H⋯O (18.7%) inter­actions, as concluded from a Hirshfeld analysis.

The title compound, [Mn(C3H7NO)4(H2O)2][Cu5(C7H4NO3)4]·C3H7NO or cis-[Mn(H2O)2(DMF)4]{Cu[12-MCCu(II)N(shi)-4]}·DMF, where MC is metallacrown, shi3− is salicyl­hydroximate, and DMF is N,N-di­methyl­formamide, crystallizes in the monoclinic space group P21/n. Two crystallographically independent metallacrown anions are present in the structure, and both anions exhibit minor main mol­ecule disorder by an approximate (non-crystallographic) 180° rotation with occupancy ratios of 0.9010 (9) to 0.0990 (9) for one anion and 0.9497 (8) to 0.0503 (8) for the other. Each penta­copper(II) metallacrown contains four CuII ions in the MC ring and a CuII ion captured in the central cavity. Each CuII ion is four-coordinate with a square-planar geometry. The anionic {Cu[12-MCCu(II)N(shi)-4]}2− is charged-balanced by the presence of a cis-[Mn(H2O)2(DMF)4]2+ cation located in the lattice. In addition, the octa­hedral MnII counter-cation is hydrogen bonded to both MC anions via the coordinated water mol­ecules of the MnII ion. The water mol­ecules form hydrogen bonds with the phenolate and carbonyl oxygen atoms of the shi3− ligands of the MCs.

The structural dimension of metal–organic frameworks (MOFs) is of great importance in defining their properties and thus applications. In particular, 2D layered MOFs are of considerable interest because of their useful applications, which are facilitated by unique structural features of 2D materials, such as a large number of open active sites and high surface areas. Herein, this work demonstrates a methodology for the selective synthesis of a 2D layered MOF in the presence of the competitive formation of a 3D MOF. The ratio of the reactants, metal ions and organic building blocks used during the reaction is found to be critical for the selective formation of a 2D MOF, and is associated with its chemical composition. In addition, the well defined and uniform micro-sized 2D MOF particles are successfully synthesized in the presence of an ultrasonic dispersion. Moreover, the laminated 2D MOF layers are directly synthesized via a modified bottom-up lamination method, a combination of chemical and physical stimuli, in the presence of surfactant and ultrasonication.

Aminoacyl-tRNA synthetases (ARSs) play essential roles in protein biosynthesis as well as in other cellular processes, often using evolutionarily acquired domains. For possible cooperativity and synergistic effects, nine ARSs assemble into the multi-tRNA synthetase complex (MSC) with three scaffold proteins: aminoacyl-tRNA synthetase complex-interacting multifunctional proteins 1, 2 and 3 (AIMP1, AIMP2 and AIMP3). X-ray crystallographic methods were implemented in order to determine the structure of a ternary subcomplex of the MSC comprising aspartyl-tRNA synthetase (DRS) and two glutathione S-transferase (GST) domains from AIMP2 and glutamyl-prolyl-tRNA synthetase (AIMP2GST and EPRSGST, respectively). While AIMP2GST and EPRSGST interact via conventional GST heterodimerization, DRS strongly interacts with AIMP2GST via hydrogen bonds between the α7–β9 loop of DRS and the β2–α2 loop of AIMP2GST, where Ser156 of AIMP2GST is essential for the assembly. Structural analyses of DRS–AIMP2GST–EPRSGST reveal its pivotal architecture in the MSC and provide valuable insights into the overall assembly and conditionally required disassembly of the MSC.

In the past three years, Dirac half-metals (DHMs) have attracted considerable attention and become a high-profile topic in spintronics becuase of their excellent physical properties such as 100% spin polarization and massless Dirac fermions. Two-dimensional DHMs proposed recently have not yet been experimentally synthesized and thus remain theoretical. As a result, their characteristics cannot be experimentally confirmed. In addition, many theoretically predicted Dirac materials have only a single cone, resulting in a nonlinear electromagnetic response with insufficient intensity and inadequate transport carrier efficiency near the Fermi level. Therefore, after several attempts, we have focused on a novel class of DHMs with multiple Dirac crossings to address the above limitations. In particular, we direct our attention to three-dimensional bulk materials. In this study, the discovery via first principles of an experimentally synthesized DHM LaNiO3 with many Dirac cones and complete spin polarization near the Fermi level is reported. It is also shown that the crystal structures of these materials are strongly correlated with their physical properties. The results indicate that many rhombohedral materials with the general formula LnNiO3 (Ln = La, Ce, Nd, Pm, Gd, Tb, Dy, Ho, Er, Lu) in the space group R3c are potential DHMs with multiple Dirac cones.

Tannerella forsythia is an oral dysbiotic periodontopathogen involved in severe human periodontal disease. As part of its virulence factor armamentarium, at the site of colonization it secretes mirolysin, a metallopeptidase of the unicellular pappalysin family, as a zymogen that is proteolytically auto-activated extracellularly at the Ser54–Arg55 bond. Crystal structures of the catalytically impaired promirolysin point mutant E225A at 1.4 and 1.6 Å revealed that latency is exerted by an N-terminal 34-residue pro-segment that shields the front surface of the 274-residue catalytic domain, thus preventing substrate access. The catalytic domain conforms to the metzincin clan of metallopeptidases and contains a double calcium site, which acts as a calcium switch for activity. The pro-segment traverses the active-site cleft in the opposite direction to the substrate, which precludes its cleavage. It is anchored to the mature enzyme through residue Arg21, which intrudes into the specificity pocket in cleft sub-site S1'. Moreover, residue Cys23 within a conserved cysteine–glycine motif blocks the catalytic zinc ion by a cysteine-switch mechanism, first described for mammalian matrix metallopeptidases. In addition, a 1.5 Å structure was obtained for a complex of mature mirolysin and a tetradecapeptide, which filled the cleft from sub-site S1' to S6'. A citrate molecule in S1 completed a product-complex mimic that unveiled the mechanism of substrate binding and cleavage by mirolysin, the catalytic domain of which was already preformed in the zymogen. These results, including a preference for cleavage before basic residues, are likely to be valid for other unicellular pappalysins derived from archaea, bacteria, cyanobacteria, algae and fungi, including archetypal ulilysin from Methanosarcina acetivorans. They may further apply, at least in part, to the multi-domain orthologues of higher organisms.