One-dimensional Linear Chain Research Articles

The effect of ligand/ metal-ligand ratio on the structural architectures of five different 1D zinc(II) coordination polymers with pyridyl derivative ligands

Five coordination compounds, [Zn(bppc)Cl]n·0.5nH2O (1) [Zn2(bppc)2(suc)]n (2), [Zn(dppb)Cl]n·nH2O (3) [Zn(dppb)Cl]n (4) [Zn2(dppb)2(bdc)]n·2nH2O(5) (Hbppc =2,6-bis(pyrazin-2-yl)pyridine-4-carboxylic acid, H2suc=succinic acid, Hdppb=4-(2,6-di(pyrazin-2-yl)pyridine-4-yl)-benzoic acid, H2bdc=1,4-benzenedicarboxylic acid), with the same one dimensions but different patterns have been hydrothermally synthesized and structurally characterized. Single crystal X-ray analysis revealed that compound 1 shows one-dimensional wave chain structure, compound 2 to 5 show one-dimensional ladder chain structure, one-dimensional V-shaped chain structure, one-dimensional linear chain structure and one-dimensional A-shaped chain structure, respectively. The structure differences of 1–5 show that ligand including auxiliary ligand and metal-ligand ratio have important influence on the final structures. Additionally, the luminescent properties of 1–5 have been investigated with fluorescent spectra in the solid state and fluorescence sensing experiments show that compound 1 exhibit a great selectivity and sensitivity for detection of Cu2+ion and nitrobenzene.

Synthesis, coordination modes, structures, and magnetic properties of halogen-substituted 2-hydroxypyridine copper(II) chloride coordination compounds

A family of 6-X-2-hydroxyprydine/pyridone (6-X-2-HOpy/pyridone) Cu(II) compounds, [Cu(6-X-2-HOpy)2Cl2] (1 X = F; 2 X = Cl) and [(6-X-2-pyridone)CuCl(μ-Cl)]2 (3 X = Cl; 4 X = Br), has been prepared. Solution-based infrared spectra displayed a correlation between tautomeric state, primarily driven by halogen identity, and coordination mode with neutral nitrogen coordination mode favored as Br ≪ Cl < F. The tautomeric state of 6-Cl-2-HOpy is influenced by metal ion concentration (M) with lactam concentration increasing as M increases. Compound 1 has F–F contacts less than the sum of the van der Waals radii but falls outside of the typical halogen bonding angle parameters, R–X•••Y = R–Y•••X = 138.2°. Compounds 1 and 2 exhibit weak antiferromagnetic exchanges, fit with a one-dimensional quantum Heisenberg antiferromagnetic linear chain (1D-QHAF) model and J/kB = −1.99(1) K and −0.92(7) K, respectively. Compounds 3 and 4 exhibit a dominating ferromagnetic exchange and an antiferromagnetic exchange and were qualitatively fit to a ferromagnetic linear chain with an interchain interaction model. This model does not accurately represent the physical parameters of the system and was used to show that both exchanges exist and are nontrivial.

Strategy for an Effective Eco-Optimized Design of Heteroleptic Cu(I) Coordination Polymers Exhibiting Thermally Activated Delayed Fluorescence.

The new series of copper(I) coordination polymers [Cu(N-N)(μ-PTA)]n[PF6]n {N-N = dmbpy (1), bpy (2), ncup (3), and phen (4)} were generated by straightforward reaction in solution or through a mechanochemical route, of [Cu(MeCN)4][PF6] with 1,3,5-triaza-7-phosphaadamantane (PTA) and the corresponding polypyridines, namely, 5,5'-dimethyl-2,2'-bipyridine (dmbpy), 2,2'-bipyridine (bpy), 2,9-dimethyl-1,10-phenanthroline (ncup), and 1,10-phenanthroline (phen). The compounds were obtained as air-stable solids and fully characterized by IR, NMR spectroscopy, and elemental analyses. The molecular structures were confirmed by single-crystal X-ray diffraction analysis (for 1, 2, and 4), revealing infinite one-dimensional (1D) linear chains driven by μ-PTA N,P-linkers. All tested Cu(I) polymeric compounds show emission at room temperature, which was attributed to thermally activated delayed fluorescence (TADF). Evidence of the involvement of the excited singlet state in the emission process is presented. Comparing the photophysical properties of 1 and 2 as well as 3 and 4, of which 1 and 3 have a stiffened structure, by introducing a methyl group to one of the ligands, we demonstrate how TADF properties depend on molecular rigidity. It is shown that stiffening of the structure reduces the flattening distortion around the Cu(I) center in the 3MLCT state. As a result, the ΔE(S1-T1) energy gap becomes smaller and the fluorescence quantum yield increases without significantly extending the emission lifetime. In particular, the ΔE(S1-T1) values for complexes 1 and 3 are among the shortest reported in the scientific literature, 253 and 337 cm-1, and the TADF lifetimes are τ(300 K) = 5.7 and 4.2 μs, respectively. The fluorescence quantum yields for these complexes are measured to be ΦPL(300 K) = 70 and 80%.

Synthesis and characterization of a luminescent diphosphine and aromatic N-heterocyclic copper(I) coordination polymer

Luminescent Cu(I) complexes have drawn considerable attention as alternative materials to precious transition metal complexes due to their low cost and electron configuration. Discrete heteroleptic diamine-diphosphine copper(I) complexes have been investigated owing to their outstanding photophysical features. However, heteroleptic copper(I) coordination polymers remain mostly unexplored. Herein, we report the synthesis and photophysical characterization of a heteroleptic copper(I) coordination polymer by employing bidentate oxybis(2,1-phenylene)bis(diphenylphosphine) (POP) diphosphine and nitrogen heterocyclic 5-[4-(1-imidazolyl)phenyl]-2H-tetrazole (ipt) as ligands. By utilizing the mixed-solvent strategy, a one-dimensional (1D) linear chain was constructed under solvothermal reaction conditions. Temperature-dependent emission spectra combined with decay time measurements demonstrate that emission originated from triplet phosphorescence at ambient temperature.

ANALOGIES BETWEEN IMAGES AND TEXTS: 'CLUSTERIZATION' PHENOMENON IN TEXTS AND DIGITAL IMAGES

We develop a number of analogies between texts and images, where different pixel-brightness levels (or gray values) in an image correspond to different linguistic elements of some level (such as letters, symbols, words, etc.) in a text. This correspondence is possible only in the case of discrete structures such as digital images. A number of practical recipes for converting two-dimensional images into one-dimensional linear chains of pixels (i.e., ‘texts’) are discussed. In particular, this can be consideration of separate rows (or columns) in an image – or a series of sequential rows (or columns) in it, where a sequential number of pixel in a ‘one-dimensional image’ is analogue of a position of linguistic element in a text. The advantages and shortcomings of these recipes are analyzed. Besides, we introduce analogues of the statistical-linguistic notions of ‘vocabulary’ and ‘rank dependence’ in the case of images. Then we clarify the possibilities for application to digital images of standard statistical-linguistic techniques for detecting keywords in texts. In particular, we remind of the phenomenon of clustering of words in a text, which is very weak or absent for so-called function words – and pronounced for keywords. A simplest clustering parameter R is introduced that relates to the first statistical moments of the probability distribution for the waiting times of a given word in a text. It quantizes the scale of the above phenomenon for this word. After that, we analyze the latter phenomenon in the ‘texts’ that correspond to two different digital images. Our main result is that the ‘texts’ corresponding to a pure white noise and a simple informative image differ notably by their R -parameters associated with different ‘words’ (i.e., brightness levels). A possible meaning of ‘keywords’ in an image is discussed, which can be associated with some ‘semantic load’ of the appropriate brightness levels. We also advise to check the availability of long-range correlations among the same brightness levels in an image. This can be done according to one of standard techniques known for the studies of correlations (e.g., fluctuation analysis or detrended fluctuation analysis). Key words : statistical linguistics, natural language processing, clustering, keywords, digital image processing.

Electron-phonon interaction in the dynamics of trap filling in quantum dots

We analyze theoretically the effects of electron-phonon interaction in the dynamics of an electron that can be trapped to a localized state and detrapped to an extended band state of a small quantum dot (QD) using a simple model system. It consists of a one-dimensional tight-binding linear chain of a few sites, having a discrete set of energy levels mimicking the discrete levels of the conduction band of the QD that is connected at its end to another site, the trap, having a single energy level well below the conduction band, where the electron is allowed to interact with a local phonon of a single frequency. In spite of its simplicity, the time-dependent model has no analytical solution but a numerically exact one can be found, producing a rich dynamics. The electronic motion is quasiperiodic in time, with oscillations around a mean value that are basic characteristics of the weak and strong coupling regimes of electron-phonon interaction and set the timescales of the system. Using values of the parameters appropriate for defects in semiconductor QDs, we find these timescales to range typically from tenths of picoseconds to a few picoseconds. The values of the time-averaged trap occupancy strongly depend on the the strength of the electron-phonon interaction and can be as large as $40%$ when the coupling is most efficient, independently of other parameters. An interesting result of the present paper is the formation of resonances at specific values of the electron-phonon coupling parameter that only exist when several levels are allowed to coherently cooperate in the filling of the trap. They are characterized by a trap occupancy that is a periodic function of time with large amplitude and period picturing an electron that is periodically trapped and detrapped. We conclude that the formation of these resonances is a robust consequence of electron-phonon interaction in small systems. Electron-phonon interaction is an efficient mechanism that can provide ca. $50%$ filling of a deep trap state on a subpicosecond to picosecond timescale, much faster than radiative decay occurring in timescales of tens of picoseconds to nanoseconds, while the occupancy of this state will be smaller than ca. $1%$ in the absence of electron-phonon coupling.

Quantum-critical properties of the long-range transverse-field Ising model from quantum Monte Carlo simulations

The quantum-critical properties of the transverse-field Ising model with algebraically decaying interactions are investigated by means of stochastic series expansion quantum Monte Carlo, on both the one-dimensional linear chain and the two-dimensional square lattice. We extract the critical exponents $\nu$ and $\beta$ as a function of the decay exponent of the long-range interactions. For ferromagnetic Ising interactions, we resolve the limiting regimes known from field theory, ranging from the nearest-neighbor Ising to the long-range Gaussian universality classes, as well as the intermediate regime with continuously varying critical exponents. In the long-range Gaussian regime, we treat the effect of dangerous irrelevant variables on finite-size scaling forms. For antiferromagnetic and therefore competing Ising interactions, the stochastic series expansion algorithm displays growing auto-correlation times leading to a reduced performance. Nevertheless, our results are consistent with the nearest-neighbor Ising universality for all investigated interaction ranges both on the linear chain and the square lattice.

Highly polymerized linear polyimide /H3PW12O40 photocatalyst with full visible light region absorption

The degree of polymerization in polyimides has significant effects on their photoelectric properties. Increase the degree of polymerization in polyimide can improve its light absorption capability as well as reduce the recombination rate of photogenerated electrons and holes. However, it is difficult to promote the polymerization of polyimides by conventional approaches, such as increasing the polymerization temperature since polyimides are susceptible to high temperature and can be decomposed. In this paper, a suitable proportion of phosphotungstic acid was introduced to increase the degree of polymerization of polyimide at a lower polymerization temperature, so as to improve the light absorption capability of the composite and inhibit the recombination of electron and hole. The p-phenylenediamine based polyimide with the one-dimensional linear polymer chain has excellent charge transfer ability, so the POM-π effect formed with phosphotungstic acid is stronger, correspondingly, the light absorption capacity of the composite photocatalyst formed is stronger than that of the cross-linked polyimide/phosphotungstic acid.

Crystal structure of 4-(anthracen-9-yl)pyridine.

The title compound, C19H13N, which crystallizes in the monoclinic C2/c space group with one half-mol-ecule in the asymmetric unit, was synthesized by Suzuki-Miyaura cross-coupling reaction of 9-bromo-anthracene with pyridin-4-ylboronic acid and purified by column chromatography on silica gel. Light-yellow crystals of 4-(anthracen-9-yl)-pyridine suitable for X-ray diffraction were collected by the solvent evaporation method. In the crystal, pairs of mol-ecules are connected by inter-molecular C-H⋯π (pyridine) inter-actions [d(H7⋯Cg) = 2.7391 (2) Å], forming cyclic centrosymmetric dimers, further resulting in an infinite one-dimensional linear chain along the c-axis direction. Weak face-to-face π-π stacking inter-actions [d(Cg⋯Cg) = 3.6061 (2) Å] link neighboring lamellar networks into the supra-molecular structure.

Exploring Cation-Anion Redox Processes in One-Dimensional Linear Chain Vanadium Tetrasulfide Rechargeable Magnesium Ion Cathodes.

For magnesium ion batteries (MIBs) to be used commercially, new cathodes must be developed that show stable reversible Mg intercalation. VS4 is one such promising material, with vanadium and disulfide anions [S2]2- forming one-dimensional linear chains, with a large interchain spacing (5.83 Å) enabling reversible Mg insertion. However, little is known about the details of the redox processes and structural transformations that occur upon Mg intercalation and deintercalation. Here, employing a suite of local structure characterization methods including X-ray photoelectron spectroscopy (XPS), V and S X-ray absorption near-edge spectroscopy (XANES), and 51V Hahn echo and magic-angle turning with phase-adjusted sideband separation (MATPASS) NMR, we show that the reaction proceeds via internal electron transfer from V4+ to [S2]2-, resulting in the simultaneous and coupled oxidation of V4+ to V5+ and reduction of [S2]2- to S2-. We report the formation of a previously unknown intermediate in the Mg-V-S compositional space, Mg3V2S8, comprising [VS4]3- tetrahedral units, identified by using density functional theory coupled with an evolutionary structure-predicting algorithm. The structure is verified experimentally via X-ray pair distribution function analysis. The voltage associated with the competing conversion reaction to form MgS plus V metal directly is similar to that of intermediate formation, resulting in two competing reaction pathways. Partial reversibility is seen to re-form the V5+ and S2- containing intermediate on charging instead of VS4. This work showcases the possibility of developing a family of transition metal polychalcogenides functioning via coupled cationic-anionic redox processes as a potential way of achieving higher capacities for MIBs.

Cyanide-Bridged Polynuclear and One-Dimensional FeIII-MnIII/II Bimetallic Complexes Based-on Pentacyanoferrite(III) Building Block: Synthesis, Crystal Structures, and Magnetic Properties

In this contribution, based-on the structurally confirmed pentacyanometallate (PPh4)2[Fe(CN)5(imidazole)]·(imidazole)·H2O (1) and the manganese compounds [Mn(L)(H2O)2]ClO4 (L = N,N-ethylenebis(3-methoxysalicylideneiminate) or [Mn(MAC)(H2O)Cl]ClO4 (MAC = 2,13-dimethyl-3,6,9,12,18-pentaazabicyclo-[12.3.1]octadeca-1(18),2,12,14,16-pentaene), two new cyanide-bridged bimetallic FeIII-MnIII/II complexes [Mn(L)(H2O)]3[Fe(CN)5(imidazole)](ClO4) (2) and [Mn(MAC)][Fe(CN)5(imidazole)]·CH3OHn (3) were successfully synthesized and characterized by elemental analysis, IR spectroscopy and X-ray structure determination. Single X-ray diffraction analysis reveals the cationic FeMn3 tetranuclear entity for complex 2, which can be further assembled into supramolecular 1D ladder-like double chain by the strong intermolecular hydrogen bond interactions. For complex 3, it can be structurally characterized as neutral one-dimensional linear single infinite chain. The magnetic investigations discover the ferromagnetic coupling between the FeIII-MnIII units in complex 2 and the antiferromagnetic coupling in complex 3 between the FeIII-MnII units through the bridging cyanide group, respectively.

Crystal-momentum-resolved contributions to multiple plateaus of high-order harmonic generation from band-gap materials

We study the crystal-momentum-resolved contributions to the high-order harmonic generation (HHG) in band-gap materials, and identify the relevant initial crystal momenta for the first and higher plateaus of the HHG spectra. We do so by using a time-dependent density-functional theory model of one-dimensional linear chains. We introduce a self-consistent periodic treatment for the infinitely extended limit of the linear chain model, which provides a convenient way to simulate and discuss the HHG from a perfect crystal beyond the single-active-electron approximation. The multi-plateau spectral feature is elucidated by a semiclassical k-space trajectory analysis with multiple conduction bands taken into account. In the considered laser-interaction regime, the multiple plateaus beyond the first cutoff are found to stem mainly from electrons with initial crystal momenta away from the Gamma point (k = 0), while electrons with initial crystal momenta located around the Gamma point are responsible for the harmonics in the first plateau. We also show that similar findings can be obtained from calculations using a sufficiently large finite model, which proves to mimic the corresponding infinite periodic limit in terms of the band structures and the HHG spectra.

Luminescent Cu(I) and Ag(I) coordination polymers: Fast phosphorescence or thermally activated delayed fluorescence

By applying two donor-acceptor motif molecules, 5,10-di(pyridin-4-yl)-5,10-dihydrophenazine (L1) and 10,10'-di(pyridin-3-yl)-10H,10'H-9,9'-spiroacridine (L2), as ligands and CuI/AgCF3CO2 as metal salt, we synthesized three coordination polymers, namely, {Cu4(L1)2I4} (CP1), {Cu(L2)I·CHCl3} (CP2) and {Ag(L2)CO2CF3·CHCl3} (CP3). X-ray crystallographic analysis revealed that three coordination polymers all feature one-dimensional (1D) linear chains which are consisting of molecular boxlike units. In comparison with low photoluminescence quantum yield (PLQY) of two ligands, three coordination polymers, CP1, CP2 and CP3, present more intense photoluminescence with PLQY of 15%, 46% and 34% at room temperature respectively. The PL emission of CP1 and CP2 at room temperature could be attributed to the fast phosphorescence with lifetime both around 5 μs due to effective intersystem crossing (ISC). Whilst, it is worth noting that CP3 exhibit thermally activated delayed fluorescence (TADF) emission at room temperature.

Synthesis, crystal structure and studies on the interaction with albumin of a new silver(I) complex based on 2-(4-nitrobenzenesulfonamido)benzoic acid.

In the present work, the two-dimensional (2D) polymer poly[[μ4-2-(4-nitrobenzenesulfonamido)benzoato-κ4O1:O1:O1':N6]silver(I)] (AgL), [Ag(C13H9N2O6S)]n, was obtained from 2-(4-nitrobenzenesulfonamido)benzoic acid (HL), C13H10N2O6S. FT-IR, 1H and 13C{1H} NMR spectroscopic analyses were used to characterize both compounds. The crystal structures of HL and AgL were determined by single-crystal X-ray diffraction. In the structure of HL, O-H...O hydrogen bonds between neighbouring molecules result in the formation of dimers, while the silver(I) complex shows polymerization associated with the O atoms of three distinct deprotonated ligands (L-). Thus, the structure of the Ag complex can be considered as a coordination polymer consisting of a one-dimensional linear chain, constructed by carboxylate bridging groups, running parallel to the b axis. Neighbouring polymeric chains are further bridged by Ag-C monohapto contacts, resulting in a 2D framework. Fingerprint analysis of the Hirshfeld surfaces show that O...H/H...O hydrogen bonds are responsible for the most significant contacts in the crystal packing of HL and AgL, followed by the H...H and O...C/C...O interactions. The Ag...Ag, Ag...O/O...Ag and Ag...C/C...Ag interactions in the Hirshfeld surface represent 12.1% of the total interactions in the crystal packing. Studies of the interactions of the compounds with human serum albumin (HSA) indicated that both HL and AgL interact with HSA.

Large-scale synthesis of van der Waals 1-dimensional material Mo6S3I6 by using a MoI2 precursor

By using a MoI2 precursor, a one-dimensional linear chain material, Mo6S3I6, was synthesized on a centimeter scale. As MoI2 can be used to form Mo6S3I6 through a gas-phase reaction, a larger amount of single crystals can be synthesized; moreover, these crystals are significantly longer than those synthesized by using Mo, S, and I powder. The synthesized Mo6S3I6 exhibited the characteristics of paramagnetic semiconductors with excellent thermal stability and a low bandgap. Furthermore, Mo6S3I6 can be separated into long nanometer-scale chains by a solution dispersion process.

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.

Au7Ag9(dppf)3(CF3CO2)7BF4]n: a linear nanocluster polymer from molecular Au7Ag8 clusters covalently linked by silver atoms.

We report the total structure determination of a covalently bonded nanocluster polymer [Au7Ag9(dppf)3(CF3CO2)7BF4]n (1). This features a one-dimensional linear chain, consisting of unique molecular building blocks, Au7Ag8(dppf)3(CF3CO2)7 clusters, which are linked together by Ag-O bonds rather than Au-Au interactions or bidentate organic bridges as previously reported.

Precise Estimation of the S = 2 Haldane Gap by Numerical Diagonalization

The Haldane gap of the S=2 Heisenberg antiferromagnet in a one-dimensional linear chain is examined by a numerical-diagonalization method. A precise estimate for the magnitude of the gap is successfully obtained by a multistep convergence-acceleration procedure applied to finite-size diagonalization data under the twisted boundary condition.

Flexible coordination polymers based on zwitterion ligands and d10 metal ions for selective sensing of nitrobenzene, Fe3+ and HSO4−

Flexible zwitterion ligands 1,1′,1″‑(2,4,6‑trimethylbenzene‑1,3,5‑triyl)‑tris(methylene)tris ‑(4‑carboxypyridinium)tribromide (L1) and 1,2,4,5‑tetrakis‑(4‑carboxylatopyridinium‑1‑methylene)benzene (L2) were used for construction of three novel luminescent d10-based coordination polymers, namely {[Cd2L12(BDC)(H2O)6]·2Br−·2EtOH·3H2O}n (1), [Zn(H2O)6]·L2·2NO3−·0.5H2O (2) and [Cd(H2O)6]·L2·2NO3−·0.5H2O (3). The structure of 1 possessed one-dimensional zig-zag linear chain, while the structure of 2 and 3 possessed three–dimensional supramolecular polymers by hydrogen bonding interaction. Complex 1 can be applied as a potential multi-functional luminescent sensing material for selective and recyclable sensing of nitrobenzene (NB), Fe3+ ion and HSO4− anion through fluorescence quenching based detection method. The structures were structurally characterized by single crystal X-ray crystallography, infrared (IR) spectroscopy, and thermo gravimetric analysis (TGA).

A one-dimensional self-assembled porous coordination polymer poly[bis(picolinato-N,O)(µ-1,2-bis(4-pyridyl)ethane-N,N′)cobalt(II)] dimethanol

A one-dimensional coordination polymer {[(Co(pic)2(bpe)]·2CH3OH}n(1) has been synthesized using [Co(pic)2(H2O)2]·2H2O where pic = picolinate as a building block and 1,2-bis(4-pyridyl)ethane (bpe) as an linker in a 1:1 M ratio. This compound was characterised by using elemental analysis, IR spectroscopy, thermogravimetric analysis and single crystal X-ray diffraction. Single crystal X-ray structural analysis revealed that the compound 1 formed by bridging bpe ligand which gives rise to the one-dimensional (1D) linear chain. In the crystal structure coordination sphere consists of two oxygen atoms and two nitrogen atoms of the two picolinato and two nitrogen atoms of two bpe ligand. Weak interactions such as hydrogen-bonding, π⋯π stacking interaction join the polymeric chain to generate three dimensional network structures. The framework is stable up to 232 °C and nitrogen adsorption measurement reveals the adsorption of 11.4 cc g−1 at P/P0∼0.95.