Metastability relationship between two- and three-dimensional crystal structures: a case study of the Cu-based compounds.
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ABSTRACT:
SUBMITTER: Ono S
PROVIDER: S-EPMC8285482 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The complete mol-ecules of the title compounds, N2,N5-bis-(pyridin-2-ylmeth-yl)pyrazine-2,5-dicarboxamide, C18H16N6O2 (I), 3,6-dimethyl-N2,N5-bis-(pyridin-2-yl-meth-yl)pyrazine-2,5-dicarboxamide, C20H20N6O2 (II), and N2,N5-bis-(pyridin-4-ylmeth-yl)pyrazine-2,5-dicarboxamide, C18H16N6O2 (III), are generated by inversion symmetry, with the pyrazine rings being located about centres of inversion. Each mol-ecule has an extended conformation with the pyridine rings inclined to the pyrazine ring by 89.17 (7)° in (I), 75.83 (8)° in (II) and by 82.71 (6)° in (III). In the crystal of (I), mol-ecules are linked by N-H⋯N hydrogen bonds, forming layers lying parallel to the bc plane. The layers are linked by C-H⋯O hydrogen bonds, forming a three-dimensional supra-molecular structure. In the crystal of (II), mol-ecules are also linked by N-H⋯N hydrogen bonds, forming layers lying parallel to the (10-1) plane. As in (I), the layers are linked by C-H⋯O hydrogen bonds, forming a three-dimensional supra-molecular structure. In the crystal of (III), mol-ecules are again linked by N-H⋯N hydrogen bonds, but here form corrugated sheets lying parallel to the bc plane. Within the sheets, neighbouring pyridine rings are linked by offset π-π inter-actions [inter-centroid distance = 3.739 (1) Å]. The sheets are linked by C-H⋯O hydrogen bonds, forming a three-dimensional supra-molecular structure. Compound (I) crystallizes in the monoclinic space group P21/c. Another monoclinic polymorph, space group C2/c, has been reported on by Cockriel et al. [Inorg. Chem. Commun. (2008), 11, 1-4]. The mol-ecular structures of the two polymorphs are compared.
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Project description:Two bis-carbamoyl-methyl-phosphine oxide compounds, namely {[(3-{[2-(di-phen-yl-phosphino-yl)ethanamido]-meth-yl}benz-yl)carbamo-yl]meth-yl}di-phenyl-phos-phine oxide, C36H34N2O4P2, (I), and diethyl [({2-[2-(di-eth-oxy-phosphino-yl)ethanamido]-eth-yl}carbamo-yl)meth-yl]phospho-nate, C14H30N2O8P2, (II), were synthesized via nucleophilic acyl substitution reactions between an ester and a primary amine. Hydrogen-bonding inter-actions are present in both crystals, but these inter-actions are intra-molecular in the case of compound (I) and inter-molecular in compound (II). Intra-molecular π-π stacking inter-actions are also present in the crystal of compound (I) with a centroid-centroid distance of 3.9479 (12) Å and a dihedral angle of 9.56 (12)°. Inter-molecular C-H⋯π inter-actions [C⋯centroid distance of 3.622 (2) Å, C-H⋯centroid angle of 146°] give rise to supra-molecular sheets that lie in the ab plane. Key geometric features for compound (I) involve a nearly planar, trans-amide group with a C-N-C-C torsion angle of 169.12 (17)°, and a torsion angle of -108.39 (15)° between the phosphine oxide phospho-rus atom and the amide nitro-gen atom. For compound (II), the electron density corresponding to the phosphoryl group was disordered, and was modeled as two parts with a 0.7387 (19):0.2613 (19) occupancy ratio. Compound (II) also boasts a trans-amide group that approaches planarity with a C-N-C-C torsion angle of -176.50 (16)°. The hydrogen bonds in this structure are inter-molecular, with a D⋯A distance of 2.883 (2) Å and a D-H⋯A angle of 175.0 (18)° between the amide hydrogen atom and the P=O oxygen atom. These non-covalent inter-actions create ribbons that run along the b-axis direction.
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Project description:The two [3.3.1] metallacryptate complexes, namely, poly[[μ3-acetato-hexa-kis-(μ-N,N-di-methyl-formamide)-bis-(N,N-di-methyl-formamide)bis-[salicyl-hydroxi-mato(2-)]hepta-kis-[salicyl-hydrox-im-ato(3-)]hexa-aluminium(III)dysprosium(III)penta-sodium(I)] N,N-di-methyl-formamide tetra-solvate monohydrate], [DyAl6Na5(OAc)(Hshi)2(shi)7(DMF)8]·4DMF·H2O or {[DyAl6Na5(C7H5NO3)2(C7H4NO3)7(C2H3O2)(C3H7NO)8]·4C3H7NO·H2O} n , 1, and poly[[di-μ4-acetato-nona-kis-(μ-N,N-di-methyl-form-amide)-octa-kis-(N,N-di-methyl-formamide)tetra-kis-[sali-cyl-hydroximato(2-)]tetra-deca-kis-[salicyl-hydroximato(3-)]dodeca-aluminium(III)didysprosium(III)deca-sodium(I)] N,N-di-methyl-form-amide 6.335-solvate], [DyAl6Na5(OAc)(Hshi)2(shi)7(DMF)8.5]2·6.335DMF or {[Dy2Al12Na10(C7H5NO3)4(C7H4NO3)14(C2H3O2)2(C3H7NO)17]·6.335C3H7NO} n , 2, where shi3- is salicyl-hydroximate and DMF is N,N-di-methyl-formamide, both consist of an aluminium-based metallacryptand. In 1 and 2, the metallacryptand encapsulates a dysprosium(III) ion in the central cavity, and the resulting metallacryptates are connected to each other via sodium-DMF linkages to generate a two-dimensional sheet. The metallacryptates of 1 and 2 are the three-dimensional analogues of metallacrowns as the metallacryptates contain a metal-nitro-gen-oxygen cyclic repeat unit throughout the complexes. For 1 the building block of the two-dimensional sheet is comprised of only one type of metallacryptate, which is connected to four neighboring metallacryptates via four sodium-DMF linkages. In 2, the building block is a dimeric unit of two metallacryptates. Each dimeric metallacryptate unit is connected to four other dimeric units via six sodium-DMF linkages. The two metallacryptates of each dimeric unit can be considered enanti-omers of each other. In both 1 and 2, chirality is imparted to the metallacryptate due to the Λ and Δ propeller configurations of the four octa-hedral aluminium ions of the metallacryptand shell.
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Project description:Liquid crystal elastomers exhibit large reversible strain and programmable shape transformations, enabling various applications in soft robotics, dynamic optics, and programmable origami and kirigami. The morphing modes of these materials depend on both their geometries and director fields. In two dimensions, a pixel-by-pixel design has been accomplished to attain more flexibility over the spatial resolution of the liquid crystal response. Here we generalize this idea in two steps. First, we create independent, cubic light-responsive voxels, each with a predefined director field orientation. Second, these voxels are in turn assembled to form lines, grids, or skeletal structures that would be rather difficult to obtain from an initially connected material sample. In this way, the orientation of the director fields can be made to vary at voxel resolution to allow for programmable optically- or thermally-triggered anisotropic or heterogeneous material responses and morphology changes in three dimensions that would be impossible or hard to implement otherwise.
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Project description:The physical properties of polycrystalline materials depend on their microstructure, which is the nano- to centimeter scale arrangement of phases and defects in their interior. Such microstructure depends on the shape, crystallographic phase and orientation, and interfacing of the grains constituting the material. This article presents a new non-destructive 3D technique to study centimeter-sized bulk samples with a spatial resolution of hundred micrometers: time-of-flight three-dimensional neutron diffraction (ToF 3DND). Compared to existing analogous X-ray diffraction techniques, ToF 3DND enables studies of samples that can be both larger in size and made of heavier elements. Moreover, ToF 3DND facilitates the use of complicated sample environments. The basic ToF 3DND setup, utilizing an imaging detector with high spatial and temporal resolution, can easily be implemented at a time-of-flight neutron beamline. The technique was developed and tested with data collected at the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Complex (J-PARC) for an iron sample. We successfully reconstructed the shape of 108 grains and developed an indexing procedure. The reconstruction algorithms have been validated by reconstructing two stacked Co-Ni-Ga single crystals, and by comparison with a grain map obtained by post-mortem electron backscatter diffraction (EBSD).
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Project description:Polarization as an important degree of freedom for light plays a key role in optics. Structured beams with controlled polarization profiles have diverse applications, such as information encoding, display, medical and biological imaging, and manipulation of microparticles. However, conventional polarization optics can only realize two-dimensional polarization structures in a transverse plane. The emergent ultrathin optical devices consisting of planar nanostructures, so-called metasurfaces, have shown much promise for polarization manipulation. Here we propose and experimentally demonstrate color-selective three-dimensional (3D) polarization structures with a single metasurface. The geometric metasurfaces are designed based on color and phase multiplexing and polarization rotation, creating various 3D polarization knots. Remarkably, different 3D polarization knots in the same observation region can be achieved by controlling the incident wavelengths, providing unprecedented polarization control with color information in 3D space. Our research findings may be of interest to many practical applications such as vector beam generation, virtual reality, volumetric displays, security, and anti-counterfeiting.
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Project description:Formyltransferase catalyzes the reversible formation of formylmethanofuran from N(5)-formyltetrahydromethanopterin and methanofuran, a reaction involved in the C1 metabolism of methanogenic and sulfate-reducing archaea. The crystal structure of the homotetrameric enzyme from Methanopyrus kandleri (growth temperature optimum 98 degrees C) has recently been solved at 1.65 A resolution. We report here the crystal structures of the formyltransferase from Methanosarcina barkeri (growth temperature optimum 37 degrees C) and from Archaeoglobus fulgidus (growth temperature optimum 83 degrees C) at 1.9 A and 2.0 A resolution, respectively. Comparison of the structures of the three enzymes revealed very similar folds. The most striking difference found was the negative surface charge, which was -32 for the M. kandleri enzyme, only -8 for the M. barkeri enzyme, and -11 for the A. fulgidus enzyme. The hydrophobic surface fraction was 50% for the M. kandleri enzyme, 56% for the M. barkeri enzyme, and 57% for the A. fulgidus enzyme. These differences most likely reflect the adaptation of the enzyme to different cytoplasmic concentrations of potassium cyclic 2,3-diphosphoglycerate, which are very high in M. kandleri (>1 M) and relatively low in M. barkeri and A. fulgidus. Formyltransferase is in a monomer/dimer/tetramer equilibrium that is dependent on the salt concentration. Only the dimers and tetramers are active, and only the tetramers are thermostable. The enzyme from M. kandleri is a tetramer, which is active and thermostable only at high concentrations of potassium phosphate (>1 M) or potassium cyclic 2,3-diphosphoglycerate. Conversely, the enzyme from M. barkeri and A. fulgidus already showed these properties, activity and stability, at much lower concentrations of these strong salting-out salts.
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Project description:Assessing skin irritation potential is critical for the safety evaluation of topical drugs and other consumer products such as cosmetics. The use of advanced cellular models, as an alternative to replace animal testing in the safety evaluation for both consumer products and ingredients, is already mandated by law in the European Union (EU) and other countries. However, there has not yet been a large-scale comparison of the effects of topical-use compounds in different cellular skin models. This study assesses the irritation potential of topical-use compounds in different cellular models of the skin that are compatible with high throughput screening (HTS) platforms. A set of 451 topical-use compounds were first tested for cytotoxic effects using two-dimensional (2D) monolayer models of primary neonatal keratinocytes and immortalized human keratinocytes. Forty-six toxic compounds identified from the initial screen with the monolayer culture systems were further tested for skin irritation potential on reconstructed human epidermis (RhE) and full thickness skin (FTS) three-dimensional (3D) tissue model constructs. Skin irritation potential of the compounds was assessed by measuring tissue viability, trans-epithelial electrical resistance (TEER), and secretion of cytokines interleukin 1 alpha (IL-1α) and interleukin 18 (IL-18). Among known irritants, high concentrations of methyl violet and methylrosaniline decreased viability, lowered TEER, and increased IL-1α secretion in both RhE and FTS models, consistent with irritant properties. However, at low concentrations, these two compounds increased IL-18 secretion without affecting levels of secreted IL-1α, and did not reduce tissue viability and TEER, in either RhE or FTS models. This result suggests that at low concentrations, methyl violet and methylrosaniline have an allergic potential without causing irritation. Using both HTS-compatible 2D cellular and 3D tissue skin models, together with irritation relevant activity endpoints, we obtained data to help assess the irritation effects of topical-use compounds and identify potential dermal hazards.
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