One-dimensional Zigzag Research Articles

High-pressure stable phases in mercury azide

Exploring the bonding properties and polymerization mechanism of the polymer phases of nitrogen-rich compounds is one of the goals of high-pressure research. Considering first-principles calculations, a particle swarm optimization structure search method has been used to study the structural evolution behavior of nitrogen in HgN3 up to 200 GPa. Three new phases with P-1, P21/m, and P-1 structures at pressures of 38 GPa, 125 GPa, and 148 GPa are identified for the first time. The theoretical calculations show that the two P-1 structures are dynamically stable at 50 GPa and 200 GPa. In these two phases, the nitrogen atoms form an infinite one-dimensional zigzag chain and connected N6 ring, respectively. Two stable structures have semiconductor properties throughout the stable pressure range, primarily due to sp2 hybridization of nitrogen atoms. Our studies provide a theoretical basis for the synthesis of polymeric nitrogen in high-pressure experiments and indicate the direction for future studies of mercury azide.

Pressure-Induced Large Volume Collapse, Plane-to-Chain, Insulator to Metal Transition in CaMn2Bi2.

In situ high pressure single crystal X-ray diffraction study reveals that the quantum material CaMn2Bi2 undergoes a unique plane to chain structural transition between 2 and 3 GPa, accompanied by a large volume collapse. Puckered Mn-Mn honeycomb layer converts to quasi-one-dimensional (1D) zigzag chains above the phase transition pressure. Single crystal measurements reveal that the pressure-induced structural transformation is accompanied by a dramatic 2 orders of magnitude drop of resistivity. Although the ambient pressure phase displays semiconducting behavior at low temperatures, metallic temperature dependent resistivity is observed for the high pressure phase, as surprisingly, are two resistivity anomalies with opposite pressure dependences, while one of them could be a magnetic transition and the other originates from Fermi surface instability. Assessment of the total energies for hypothetical magnetic structures for high pressure CaMn2Bi2 indicates that ferrimagnetism is thermodynamically favored.

Supramolecular networks and Hirshfeld surfaces of oxydiacetic acid and iminodiacetic acid salts.

Oxydiacetic acid (Oda) and iminodiacetic acid (Ida) have been combined with two diamines, namely ethylenediamine (en) and o-phenylenediamine (o-phen), to give three molecular crystals of compositions [(Oda2-)(en2+)]·H2O (Odaen), [(Ida-)(0.5en+)] (Idaen) and [(Oda-)(o-phen+)] (Odaophen). Single crystal X-ray structure determination of the three molecular salts revealed that the hydrogen bonding interactions form distinct supramolecular chains. In Odaen, water molecules and Oda2- anions generate one-dimensional supramolecular chains where two chains overlap each other in zigzag form. In Odaophen, Oda- anions generate a one-dimensional linear supramolecular chain. In Idaen, both intermolecular and intramolecular proton transfer occurs. Ida- anions generate a one-dimensional zigzag chain. These one-dimensional supramolecular chains extend to form different two-dimensional supramolecular chains by the interaction of diaminium and monoaminium cations. Intermolecular close contacts are also examined using Hirshfeld analysis to reveal similarities and differences in the crystal structures.

A 1D Co(II) coordination polymer based on semi-rigid bis(thiabendazole) and butane-1,2,3,4-tetracarboxylic acid linkers: synthesis, crystal structure, fluorescence sensing and photocatalytic properties

A Co(II)-based ternary coordination polymer with formula {[Co(BTC)0.5(L)(H2O)]·3H2O}n (NCST-2, NCST = North China University of Science and Technology) was constructed from 1,2-bis(thiabendazol-1-ylmethyl)benzene (L) and butane-1,2,3,4-tetracarboxylic acid (H4BTC) under hydrothermal conditions. NCST-2 features a one-dimensional zigzag chain, which is further extended through OH⋯O hydrogen bond and π⋯π stacking interactions into a three-dimensional supramolecular network. NCST-2 exhibits highly selective and recyclable performance for the fluorescence sensing of Fe3+ in aqueous solution with a linear detection range of 0–400 μM and a detection limit of 0.12 μM. NCST-2 displays high photocatalytic activities for degrading methylene blue (MB) under UV irradiation. The possible mechanism of the photodegradation towards MB was investigated in detail.

Magnetic and electrical properties of the ternary compound U2Ir3Si5 with one-dimensional uranium zigzag chains

The physical properties of the single-crystalline ${\mathrm{U}}_{2}{\mathrm{Ir}}_{3}{\mathrm{Si}}_{5}$, a new ternary uranium compound with ${\mathrm{U}}_{2}{\mathrm{Co}}_{3}{\mathrm{Si}}_{5}$-type orthorhombic structure, are investigated by means of magnetic susceptibility $\ensuremath{\chi}(T)$, specific heat $C(T)$, electrical resistivity $\ensuremath{\rho}(T)$, and high-field magnetization $M(H,T)$ measurements. ${\mathrm{U}}_{2}{\mathrm{Ir}}_{3}{\mathrm{Si}}_{5}$ undergoes an antiferromagnetic transition at ${T}_{N}=36$ K followed by a first-order phase transition at ${T}_{0}=25.5$ K. The sharp peak in $C(T)$ at ${T}_{0}$ and the obvious hysteresis behavior in $\ensuremath{\chi}(T),\ensuremath{\rho}(T)$, and $M(H,T)$ around ${T}_{0}$ provide strong evidence for the first-order phase transition. The $\ensuremath{\rho}(T)$ measurements along the $a$ and $b$ axes reveal the negative temperature coefficients of resistance over a wide temperature range, which can be understood based on the semiconductorlike narrow band gap model or the Kondo effect. The $M(H)$ curve measured at 4.2 K along the $b$ axis shows three-step metamagnetic transitions within a narrow field region around 200 kOe and a large hysteresis near the first transition field, while the ${M}_{H\ensuremath{\parallel}a}(H)$ and ${M}_{H\ensuremath{\parallel}c}(H)$ curves show no transitions up to 560 kOe suggesting the strong magnetic anisotropy. A possible mechanism of the first-order phase transition at ${T}_{0}$ is the occurrence of a magnetic quadrupolar order, resulting from the quasi-one-dimensional uranium zigzag chain.

Effect of photonic spin-orbit coupling on the topological edge modes of a Su-Schrieffer-Heeger chain

Micropillar lattices offer exciting prospects for the field of topological photonics. Confinement in flexible geometries with configurable pseudospins such as the intrinsic TE-TM splitting allows for the engineering of photonic bands with nontrivial topologies. In this work, the authors study experimentally the influence of the photonic spin-orbit coupling present in microcavities on the topological edge modes of a Su-Schrieffer-Heeger model for photons using one-dimensional zigzag chains of micropillars. The findings open a route to manipulation of topological states in photonic lattices.

Three cuprous coordination polymers based on bisbenzoxazole: Syntheses, structures, luminescence and electrochemical properties

Three cuprous coordination polymers, namely: {[Cu(BBO)3]·PF6}n (1), {[Cu(BBO)2(CH3CN)2]·BF4}n (2) and {[Cu(BBO)2(SPPh3)]·BF4}n (3), bearing a bisbenzoxazole ligand, 2,2′-(1,4-butanediyl)bis-1,3-benzoxazole (BBO), have been synthesized, and structurally characterized by elemental analyses, IR, UV–Vis and single-crystal X-ray diffraction. The structural analysis revealed that the structures of coordination polymers 1 and 3 are both three-coordinated and show distorted trigonal planar geometry, but 2 is four-coordinated and a slightly distorted tetrahedron environment. In coordination polymer 1, adjacent copper(I) ions were bridged by three independent BBO to form a two-dimensional planar layer framework in which PF6− anion is filled in the hole. Two BBO link Cu(I) ions into a one-dimensional zigzag chain in coordination polymer 2, while acetonitrile as an ancillary ligand distributed on both sides of the one-dimensional chain. Coordination polymer 3 exhibits a single-stranded helix chain structure by two BBO bridging adjacent copper(I) ions. Luminescence properties investigation show that 1 have two emission peaks, which attributed to π–π* and n–π* transitions. However 2 and 3 only had one emission peak, which may be attributed to [MLCT(d10(Cu) → π*]. This may be due to the synergy of the auxiliary ligands in coordination polymers 2 and 3. The cyclic voltammogram of 1–3 represent quasi-reversible Cu2+/Cu+ pairs.

Hydrogen-bonded 3D network of d10-metal halide coordination polymer containing N-(3-pyridinyl) nicotinamide: influence of ligand conformation, halide anions and solvent

The crystal structures of four new d10-metal halide coordination polymers are determined as one-dimensional (1D) zigzag chains which are in contact with each other by C/N–H⋯X (X = Cl, Br, I) hydrogen bonds.

Studies of Er(iii)–W(v) compounds showing nonlinear optical activity and single-molecule magnetic properties

Studies of {[Er(dma)5][W(CN)8]}n (1) showing nonlinear optical effect of second harmonic generation, and [Er(dma)5(H2O)2]·[W(CN)8]·dma·H2O (2) and [Er(dma)4(H2O)3]·[W(CN)8]·dma·3H2O (3) revealing field-induced single molecule magnet behavior.

A Mercury(II) Mixed-Ligand Coordination Polymer Constructed from 4,7-Diphenyl- 1,10-Phenanthroline and Thiocyanate Ligands: Crystal Structure Studies, Spectroscopic Charactrization, And Thermal Analyses

A new mixed-ligand coordination polymer [Hg(Ph2phen)(μ1,3-SCN)(SCN)]n (1) is prepared from Hg(SCN)2 and 4,7-diphenyl-1,10-phenanthroline (Ph2phen) in methanol. Suitable crystals for the X-ray diffraction measurement are obtained by methanol diffusion into a DMSO solution. Complex 1 is characterized by spectral methods (IR, UV-Vis, 13C{1H}NMR, 1H NMR, and luminescence), elemental analysis (CHNS), thermal analysis (TG, DTA), and single crystal X-ray diffraction. The structure of 1 is based on onedimensional zigzag chains running along the c axis. The luminescence spectrum shows stronger emission than that of free 4,7-diphenyl-1,10-phenanthroline.

Two low-dimensional transition metal coordination polymers constructed from thiophene‑2,5‑dicarboxylic acid and N/O-donor ligands: Syntheses, structures and magnetic property

Two low-dimensional transition metal coordination polymers (CPs), namely, Co(TDC)(Hdmea)2 (1), [Mn(TDC)(5,5′‑dmbpy)(H2O)]n (2) (H2TDC = thiophene‑2,5‑dicarboxylic acid, Hdmea = N,N‑dimethylethanolamine, 5,5′‑dmbpy = 5,5′‑dimethyl‑2,2′‑dipyridyl) have been synthesized and characterized. Compound 1 which is the first coordination compound containing the H2TDC and chelating Hdmea ligands so far features an isolated structure containing the centrosymmetric dinuclear [Co(TDC)(Hdmea)2]2 unit. Notably, the imidazole ligand as one of the reactants is not incorporated into the final structure of compound 1, but it is important to obtain the single crystals suitable for single–crystal X-ray diffraction analysis. Compound 2 possesses a one-dimensional (1D) zigzag chain based on the [Mn(TDC)(5,5′‑dmbpy)(H2O)] building unit. In addition, the magnetic property of compound 2 is investigated.

High-Pressure Synthesis, Structural, and Spectroscopic Studies of the Ni-U-O System.

The first comprehensive structural study of the Ni-U-O system is reported. Single crystals of α-NiUO4, β-NiUO4, and NiU3O10 were synthesized, and their structures were refined-using synchrotron single-crystal X-ray diffraction data supported by X-ray absorption spectroscopic measurements. α-NiUO4 adopts an orthorhombic structure in space group Pbcn and is isostructural to CrUO4 containing corrugated two-dimensional (2D) layers of corner-sharing UO6 polyhedra and edge-sharing one-dimensional (1D) zigzag α-PbO2 rutile-like chains of NiO6 polyhedra in the [001] direction. β-NiUO4 is isostructural to MgUO4 and has an orthorhombic structure in space group Ibmm, which contains alternating 1D chains of edge-sharing UO6 and NiO6 polyhedra in the [001] direction as in regular TiO2 rutile. NiU3O10 forms a triclinic structure in space group P1̅ and is isostructural with CuU3O10, where it forms a three-dimensional (3D) framework structure built through a mixture of UO6 and UO7 polyhedra in which the NiO6 polyhedra sit isolated within the framework. X-ray absorption near-edge structure (XANES) measurements, conducted using XANES mapping of single crystals, support the presence of hexavalent uranium in the three structures. The polymorphs of NiUO4 were found to only form under high-pressure and high-temperature conditions (≥4 GPa and 700 °C). It is argued that this is a consequence of the relative size difference between the Ni2+ and U6+ cations, where the Ni2+ cation is effectively too small for the Ibmm structure and too large for the Pbcn structure to form under ambient pressure conditions. This does not appear to be an issue for NiU3O10, which forms under ambient pressure conditions, where NiO6 polyhedra sit isolated within the framework of 3D connected UO6/UO7 polyhedra. Synthesis conditions indicate that β-NiUO4 is the preferred higher-pressure phase and that the transformation to this occurs irreversibly at a temperature between 950 and 1000 °C, when P = 4 GPa. The routes toward the synthesis of the oxides and the associated structural and spectroscopic results are described with respect to the structural chemistry of the Ni-U-O system, the larger AUO4 family of oxides (A = divalent or trivalent cation), and also their relation to the rutile-related family of oxides.

Syntheses, structures, and properties of three mixed-ligand complexes based on 3,6-bis(imidazole-1-yl)pyridazine

Three new coordination polymers [Co(L)(1,2,4,5-BTC)0.5(H2O)]n (1), {[Ni(L)(1,2-BDC)(H2O)3]·H2O}n (2) and {[Zn3(L)2(1,3,5-BTC)2(H2O)2]·3H2O}n (3) [L = 3,6-bis(imidazole-1-yl)pyridazine, H4BTC = 1,2,4,5-Benzenetetracarboxylic acid, H2BDC = 1,2-Benzenedicarboxylic acid, H3BTC = 1,3,5-Benzenetricarboxylic acid] were synthesized based on a rigid ligand L and different aromatic carboxylic acid ligands under solvothermal conditions. The structures of the complexes 1–3 were determined by single crystal X-ray diffraction and further characterized by elemental analyses, IR spectroscopy, powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA). In addition, UV–vis diffuse-reflectance spectra demonstrate wide band gaps. The structural analysis reveals that complex 1 features a two-dimensional (2D) layer structure with a 6-connected sql topological net. Complex 2 shows a one-dimensional (1D) zigzag chain, while complex 3 displays a three-dimensional (3D) coordination network which exhibits an intriguing (5,5,6)-connected novel topological net with the point symbol of {32·42·53·63}2{32·44·54·63·72}. Moreover, the luminescence property and lifetimes of complex 3 has been measured at room temperature. Furthermore, in the complex-catalyzed homocoupling reaction of 4-substituted aryl iodides, the catalytic activities of complexes 1–3 have also been studied and discussed.

Reversible desorption and absorption of water in a zinc-based coordination polymer nanostructure

A zinc-based coordination polymer [Zn(μ2-3-Clb)2·H2O]n (1), (3-HClb = 3-chloro benzoic acid), has been synthesized and structurally characterized by single crystal X-ray crystallography. It composed from one-dimensional zigzag chains but secondary hydrogen bonding interaction, extended its structure and two-dimensional supramolecular network was formed. Compound 1 nanostructure was synthesized by sonochemical procedure. Reversible desorption and adsorption of water in this zinc coordination polymer were studied by IR spectroscopy, thermo gravimetric and differential thermal analyses (TG-DTA), X-ray powder diffraction (XRD) and scanning electron microscopy (SEM).

Crystal polymorphs of 6-[(phenylcarbamoyl)oxy]hexa-2,4-diyn-1-yl isonicotinate.

The title compound, C19H14N2O4, was found to have two crystal polymorphs, in which the molecular structures of the diacetylenic compound are broadly similar. The main structural difference between the polymorphs concerns the intermolecular hydrogen-bonding motifs adopted, namely a one-dimensional zigzag polymer linked by N-H...N(py) (py is pyridine) interactions in polymorph I and a centrosymmetric dimeric motif formed by N-H...O=C interactions in polymorph II. The diacetylene cores of the molecules stack along the a and b axes in polymorphs I and II, respectively. It was found that only the molecular arrangement in polymorph II satisfies Baughman's criterion to afford polydiacetylenes (PDAs) by thermal annealing or irradiation with light. This predicted polymerization activity was confirmed by experiment.

Synthesis and characterization of new organic–inorganic hybrid compounds based on Sb, with a perovskite like structure

Two new perovskite-related organic–inorganic hybrid compounds, based on Sb were synthesized and characterized. Their structure, optical and vibronic properties were studied. The benzylamine antimonium iodide (C6H5CH2NH3)3Sb2I9 has a 0 dimensional structure consisting of two face sharing octahedrals surrounded by the organic cations. The benzylamine antimonium bromide (C6H5CH2NH3)2SbBr5 consisting of SbBr5−2 anions forming columns of corner sharing octahedrals and the benzylammonium cations were located in the free cavities between the one-dimensional zigzag chains. Both of them show strong absorption at the UV region and furthermore that with I absorbs also at a significant part of the Visible spectra. Their band gaps were calculated from their absorption spectra at 2.87 eV for the Br-based and at 2.42 eV for the I-based.

Interfacial Self-Assembly and Oriented Attachment in the Family of PbX (X = S, Se, Te) Nanocrystals.

The realization of materials with new optoelectronic properties draws much scientific attention toward the field of nanocrystal superstructures. Low-dimensional superstructures created by interfacial assembly and oriented attachment of PbSe nanocrystals are a striking example because theory showed that PbSe sheets with a honeycomb geometry possess non-trivial flat bands and Dirac cones in the valence and conduction bands. Here, we report on the formation of one-dimensional linear and zigzag structures and two-dimensional (2D) square and honeycomb structures for the entire lead chalcogenide family: PbX (X = S, Se, Te). We observe that PbTe, with a lower bulk melting temperature and enthalpy of formation than those of PbSe, shows a higher nanocrystal surface reactivity, such that the surface must be passivated and the reaction conditions moderated to obtain reasonably ordered superstructures. The present findings constitute a step forward in the realization of a larger family of atomically coherent 2D superstructures with variable IV–VI and II–VI compositions and with electronic properties dictated by the nanogeometry.

Crystal Structure and Superconductivity of Tetragonal and Monoclinic Ce1–xPrxOBiS2

Ce1- xPr xOBiS2 powders and Ce0.5Pr0.5OBiS2 single crystals were synthesized and their structure and superconductive properties were examined by X-ray diffraction, X-ray absorption, electronic resistivity, and magnetization. While PrOBiS2 was found to be in a monoclinic phase with one-dimensional Bi-S zigzag chains showing no superconductive transition above 0.1 K, CeOBiS2 was in a tetragonal phase with two-dimensional Bi-S planes showing zero resistivity below 1.3 K. In the range x = 0.3-0.9 in Ce1- xPr xOBiS2, both monoclinic and tetragonal phases were formed together with zero resistivity up to a maximum temperature of 2.2 K. A Ce0.5Pr0.5OBiS2 single crystal, which showed both zero resistivity and a decrease in magnetization at ∼2.4 K, presented a tetragonal structure. Short Bi-S bonding in flat two-dimensional Bi-S planes and mixed Ce3+/Ce4+ were characteristic features of the Ce0.5Pr0.5OBiS2 single crystal, which presumably triggered its superconductivity.

(C6H13N)2BiI5: A One-Dimensional Lead-Free Perovskite-Derivative Photoconductive Light Absorber.

Lead-free organic-inorganic hybrid perovskites have recently attracted intense interest as environmentally friendly, low-cost, chemically stable light absorbers. Here, we reported a new one-dimensional (1D) zigzag chainlike light-absorbing hybrid material of (C6H13N)2BiI5, in which the corner-sharing octahedral bismuth halide chains are surrounded by organic cations of tetramethylpiperidinium. This unique zigzag 1D hybrid perovskite-derivative material shows a narrow direct band gap of 2.02 eV and long-lived photoluminescence, which is encouraging for optoelectronic applications. Importantly, it behaves as a typical semiconducting material and displays obvious photoresponse in the visible-light range. This work opens a potential pathway for the further application of 1D lead-free hybrids.

Geometric structure of Sn dopants in sputtered TiO2 film revealed by x-ray absorption spectroscopy and first-principles DFT calculations

The crystal structure of tin (Sn)-doped titanium dioxide (TiO2) film was investigated by using x-ray absorption fine structure (XAFS) measurement and first principle calculations. XAFS measurements suggest that Sn doping can enhance the growth of rutile TiO2 phase, where Sn ions are considered to substitute into Ti sites with a valence of 4+. First principles calculation reveals that Sn doping can reduce obviously the formation energy of the rutile phase. By comparing the measured and calculated XAFS spectra, we found that the geometric structure of Sn dopant can be understood as the alignment of SnO6 tetrahedrons through a corner oxygen in the Sn-doped TiO2 film, that is, the Sn ions substituted in the Ti sites and made a one-dimensional zigzag ‘–Sn–O–Sn–’ chain.