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A Functional 2D Coordination Polymer Exhibiting Luminescent Detection of Nitroaromatics
摘要： A polyfluorinated-aromatic carboxylic acid has been designed and synthesized by the acylation reaction, tetrafluoro-bis-(3,5-dicarboxyphenyl)terephthalamide (H4bdtfa), which assembled with Zn2+ ions in the mixed solvents of DMF, py and H2O under solvothermal conditions to produce a 2D coordination polymer (CP), {[Zn2(bdtfa)(py)3(H2O)]·2DMF}n (1), (py = pyridine, DMF = N,N'-dimethylmethanamide). The final structure has been carefully characterized by various methods including single-crystal X-ray diffraction, powder X-ray diffraction (PXRD), infrared (IR) spectrum, and thermogravimetric (TG) analysis. Two types of four-coordinated Zn2+ centers present a two-dimensional ‘sql’-type layer through bdtfa4– ligands, and the adjacent layers are connected through hydrogen bonds and π···π stacking interactions to produce a 3D supramolecular framework. Luminescent results reveal that CP 1 can be regarded as a highly sensitive sensor for detecting nitroaromatics based on the fluorescence quenching effect. Moreover, the reason for the luminescent response of CP 1 towards nitroaromatics has been investigated by theoretical calculation, which indicates that the quenching reason can be primarily due to the energy- and electron-transfer as well as electrostatic interaction between nitroaromatics and CP 1.
关键词： Luminescent sensor,Nitroaromatics,Coordination polymer,Crystal structure
更新于2025-09-23 15:22:29
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Study of the effect of irradiation with Fe<sup>7+</sup> ions on the structural properties of thin TiO<sub>2</sub> foils
摘要： Thin foils based on the TiO2 phase of brookite, 620 nm thick, were obtained by magnetron sputtering. The samples were irradiated at the DC-60 heavy ion accelerator of the Astana branch of the Institute of Nuclear Physics with Fe7+ ions with an energy of 85 MeV with a fluence of 1×1011 to 1×1014 ions/cm2. The dependences of the change in the concentration of defects in the structure of thin films on the radiation dose are established. It has been established that an increase in the irradiation fluence of up to 1014 ions/cm2, characteristic of the formation of defect overlap regions, leads to a sharp decrease in the degree of crystallinity and an increase in the lattice parameters. That is caused by the formation of a large number of disorder regions and displaced atoms in the structure, which migrate along the crystal lattice to additional distortions and voltages, with the subsequent formation of hillocks.
关键词： ionizing radiation,thin foils,crystal structure defects,magnetron sputtering
更新于2025-09-23 15:22:29
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Synthesis, Crystal Structure and Fluorescent Properties of Dinuclear Zinc Complex
摘要： A dinuclear zinc complex [Zn2(qnal)2(CH3COO)2] (Hqnal: N-(8'-quinolyl)-2-hydroxy-1-naphthaldimine) was synthesized and characterized by X-ray crystallography. The complex crystallizes in monoclinic system, space group C2/c with a = 40.00(3), b = 7.690(5), c = 27.492(16) ?, β = 120.446(11)°, V = 17290(8) ?3, Z = 8. Dc = 1.537 g/cm3, Mr = 843.48, F(000) = 3456, μ(MoKα) = 1.374 mm-1, S = 1.033, R = 0.0403 and wR = 0.1049 for 4454 observed reflections (I > 2σ(I)). It exhibits a 3D supramolecular architecture constructing by π-π stacking interactions between quinolyl and naphthyl rings and shows luminescent property in the yellow region.
关键词： Zinc complex,Dinuclear,Fluorescence,Crystal structure
更新于2025-09-23 15:22:29
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Improved Transistor Performance by Modulating Molecular Packing with Donor and Acceptor Moieties
摘要： The joint of the donor and acceptor moieties allows a facile and effective strategy to develop novel organic conjugated materials. However, few works report the understanding of the donor-acceptor interactions at the molecular level. Herein, we develop three small molecules contain one acceptor motif with different amounts of the donor unit. By the combination of theoretical calculation and energy level characterization, the lowest occupied molecular orbital (LUMO) levels of the three molecules were proven to be almost identical. The molecular packing modes were evaluated from crystal structure prediction. Due to the donor-acceptor interactions, the packing mode can be tuned from the 1D slipped stacking to the 2D brick layer. The 2D molecular packing and charge transport channel endowed the materials a higher electron mobility of 3.29 cm2 V?1 s?1 in the single-crystal field-effect transistors after such modulation.
关键词： organic field-effect transistor,conjugated molecules,donor-acceptor,crystal structure prediction
更新于2025-09-23 15:22:29
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Syntheses, X-Ray Crystal Structures, Emission Properties and DFT Calculations of Monoprotonated Polypyridines
摘要： Monoprotonated compounds [(L)HPF6] were prepared by the reaction of (L = bpy, phen, dpphen, bqn and ppy) with concentrated HCl in water. Monoprotonated pyridine rings are hydrogen bonded intramolecularly to the adjacent pyridine ring and intermolecularly to the adjacent PF6- in compounds. These hydrogen bonds restrain the nonradiative decay to produce intense emission. Density functional theory was applied to interpret the planarity in compounds. The attachment of one proton to the nitrogen in [(dpphen)HPF6] and [(bqn)HPF6] leads to the strong emission in acetonitrile (Φ = 0.046 and 0.097, respectively). In particular, the attachment of one proton to the ppy nitrogen results in exhibiting a strong emission with a large quantum yield (Φ = 0.264).
关键词： crystal structure,DFT calculations,blue emission,monoprotonated polypyridine
更新于2025-09-23 15:22:29
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Synthesis, Crystal Structure, and Properties of a Zn(II) Coordination Polymer Based on a Difunctional Ligand Containing Triazolyl and Carboxyl Groups
摘要： A new compound, namely, [Zn(L)2]n (1) was obtained by the reaction of 2-methyl-4-(4H-1,2,4-triazol-4-yl) benzoic acid (HL) with ZnSO4·7H2O, and the compound was characterized by single-crystal X-ray diffraction, infrared spectroscopy, elemental analysis, powder X-ray diffraction (PXRD), and thermogravimetric analysis. The linear HL ligands were deprotonated to be L? anions and act as two-connectors to link Zn2+ to form a two-dimensional (2D) lay structure with (4, 4) topology. The large vacancy of 2D framework allows another layer structure to interpenetrate, resulting in the formation of 2D + 2D → 2D parallel interpenetration in 1. The weak interactions, such as hydrogen bonding and π–π stacking interactions, connect the adjacent 2D layers into a three-dimensional (3D) coordination polymer. The solid-state UV-visible spectroscopy and luminescent property have also been studied.
关键词： supramolecular polymer,spectral property,crystal structure
更新于2025-09-23 15:22:29
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Synthesis, crystal structure and luminescence of two barium(II) compounds: from mono- to bis-tetrazole carboxylic acids
摘要： Tetrazole carboxylates are acknowledged as bifunctional ligands for the construction of new coordination architectures. Two new coordination compounds, [Ba(atzpa)2(H2O)3]n·2nH2O (1) and [Ba2(dtzpda)(H2O)]n (2) have been prepared by solvothermal reactions of BaCl2·2H2O with Hatzpa or H4dtzpda, respectively (Hatzpa = 5-aminotetrazole-1-propanoic acid, H4dtzpda = 3,3-di(1H-tetrazol-5-yl)pentanedioic acid). The X-ray diffraction results reveal that compound 1 is a linear chain in which atzpa acts as a tridentate ligand to bridge adjacent Ba2+ ions in a μ1,1,3-COO mode. In contrast, compound 2 is a three-dimensional network where dtzpda4? acts as a dode-dentate ligand to bridge various Ba2+ ions. Furthermore, the luminescence of Hatzpa, H4dtzpda, compounds 1 and 2 in the solid state at room temperature were investigated.
关键词： Hatzpa/H4dtzpda,Crystal structure,Ba(II),Luminescence
更新于2025-09-23 15:22:29
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SERS-signal optimised AgNPs-plated-ZnO nanoflower-like structure synthesised for sensing applications
摘要： AgNPs-plated-ZnO nano?ower (NFs)-like structures (Ag@ZnO NFs) with optimised signals were synthesised via wet chemical method at different temperatures (50–80 °C). The enhancement factors (EFs) computed for the resultant Ag@ZnO ranged between 2.36–8.46×10^7 obtained at the different temperatures using 4-aminothiophenol (4-ATP). The achieved EF results indicate Ag@ZnO synthesised at 50 °C gave the best enhancement. It was therefore selected, characterised and used to fabricate a SERS-based nanosensor for the detection of 2,4-dichlorophenoxyacetic acid (2,4-D) with a limit of detection (LOD) of 2.87×10^{-3} μg/L realised.
关键词： Raman,Crystal structure,Sensor,Metallic composite
更新于2025-09-23 15:22:29
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Ce(IO3)2F2·H2O: The First Rare Earth Iodate Fluoride with Large Second Harmonic Generation Response
摘要： The first rare earth iodate fluoride, Ce(IO3)2F2·H2O, has been synthesized via hydrothermal method. In the structure, the CeO5F4 polyhedra connect with isolated IO3 groups to form one-dimensional infinite 1∞[Ce(IO3)2F2] chains, which interconnect with each other by weak hydrogen bond to construct the whole structure. Ce(IO3)2F2·H2O produces a large second harmonic generation response, which is 3 times that of KDP. Theoretical calculations using density functional theory and dipole moments were executed to illustrate the relationships between the structure and the properties. The results show that Ce(IO3)2F2·H2O is a new iodate fluoride with novel structure and has potential applications in the field of nonlinear optics.
关键词： crystal structure,iodate fluorides,density functional calculations,cerium iodates,1∞[Ce(IO3)2F2] chain
更新于2025-09-23 15:21:21
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3D energy framework of a benzophenone acidic dimer
摘要： 3-benzoyl-4-hydroxybenzoic acid (3) was synthesized, spectroscopically characterized and the crystal structure was determined using single crystal X-ray diffraction method. In addition, the thermal studies were carried out using thermogravimetric analysis (TGA). The dihedral angle between phenyl rings is 59.21(13)o and the intramolecular hydrogen bond O2---H2…O1 (S6 ring motif) is observed. The carboxylic inversion dimers linked by pairs of O4---H4…O3 hydrogen bonds generates R22(8) ring motif. The inter-contacts (2D Fingerprint plots) and enrichment ratio (E) are calculated using Hirshfeld surfaces computational method. The molecular packing was visualized in terms of dispersion, electrostatic and total energies using three-dimensional energy-framework analyses. The electrostatic energy term dominates in the crystal packing over the dispersion energy term. The thermal stability study of the 3 is measured to be 255oC, which is due to the presence of acidic dimers.
关键词： 3D-Energy frameworks,crystal structure,Benzophenones,Enrichment ratio,dimer
更新于2025-09-23 15:21:21