Three silver coordination polymers constructed from 4,4′-bipyridine-like ligands and 2,5-thiophenedicarboxylic acid: crystal structures and photocatalytic performances

Anion-Directed Self-Assembly of Calix[4]arene-Based Silver(I) Coordination Polymers and Photocatalytic Degradation of Organic Pollutants

Coordination polymers (CPs) have recently emerged as promising candidates for heterogeneous photocatalysis due to their structural designability and tunable properties. Herein, we developed two novel Ag(I)-calix[4]arene coordination polymers with the formula {[Ag₂(μ-NO₃)L¹]}_n (CP 1) and {[AgL¹]·PF₆}_n (CP 2) (L¹ = 2-mercapto-5-methyl-1,3,4-thiadiazole resorcinol calix[4]arene). Crystallography revealed that anion coordination and self-inclusion behavior induced the cavitand and silver ions to self-assemble into well-defined CPs 1 and 2 with different topological coordination frameworks, respectively. Furthermore, CPs 1 and 2 display high photocatalytic activity for the photodegradation of rhodamine B (RhB) and methyl orange (MO) in an aqueous solution under mild conditions (WLED and UV irradiation). The comparison results demonstrate that CP 1 exhibited better photocatalytic performance than CP 2, which correlated well with the differences in their molecular structure and HOMO-LUMO energy gaps. The photocatalysis products and possible intermediates were successfully monitored and determined using mass spectrum, gas chromatography, and electron paramagnetic resonance measurements. The rational photocatalysis mechanism was further investigated and proposed.

Synthesis, crystal structure and photophysical properties of bis-[2,6-di-fluoro-3-(pyridin-2-yl)pyridine-κN](tri-fluoro-methane-sulfonato-κO)silver(I)

In the title compound, [Ag(CF3SO3)(C10H6F2N2)2], the AgI centre adopts a highly distorted trigonal-planar coordination environment resulting from its coordination by one O atom of the tri-fluoro-methane-sulfonate anion and the pyridine N atoms of two crystallographically independent 2',6'-di-fluoro-2,3'-bi-pyridine ligands, which display very similar conformations to one another. Pairwise Ag⋯O-SO2CF3 - [Ag⋯O = 2.8314 (14) Å] inter-actions and inter-molecular C-H⋯O inter-actions between inversion-related units lead to the formation of an eight-membered cyclic dimer in which the silver atoms are separated by 6.2152 (3) Å. In the crystal, the dimers are linked through C-H⋯O hydrogen bonds, halogen⋯π and weak π-π stacking inter-actions, resulting in the formation of a three-dimensional supra-molecular network. The title compound exhibits a strong and broad emission band from 400 nm to 550 nm in solution and its photoluminescence quantum efficiency is estimated to be ca 0.2, indicating that the title compound could have applications as an emitting material in organic light-emitting diodes (OLEDs).

Two New Coordination Polymers: Selective Detection of Cu(II) Ion and Treatment Activity on Inner Ear Damage

In the current study, on the basis of 1,3,5-tris(2-methylimidazol-1-yl)benzene (timb), a designed tripodal connector, two new transition metal coordination polymers (CPs), {[Cu4(timb)2(Br-IPA)4]·5H2O}n (1) and {[Zn(timb)0.5(NH2-IPA)]·4H2O}n (2) have been generated with the mixed ligand method by the reaction between the timb and corresponding metal salts in the existence of dissimilar functional isophthalic acid (H2IPA) ligands. Furthermore, the Zn(II)-based complex 2 displays high sensitivity in the detection of Cu(II) ion in water. The neural stem cells proliferation after treated via compounds was detected with Cell Counting Kit-8 detection assay. And the real time reverse transcription polymerase chain reaction was carried out for the investigation of the differentiation function of the neural stem cells after the compound 1 treatment and compound 2 treatment. Further, molecular docking simulations confirmed that the biological activity that has been observed from experiments were from the carboxyl group on the Cu complex, in contrast, the imidazole groups were only used for binding with the Cu metal ion to retain the complex structure.

Photostable Ag(I)-Based Metal-Organic Framework: Synthesis, Structure, and Photocatalytic Selective Oxidation Properties

For Ag(I)-based photocatalysts, the photoreduction of Ag⁺ to metallic Ag is an unignorable issue, which is the major reason for their instability. If electrically neutral excitons rather than electrons were produced over Ag(I)-based photocatalysts, the photoreduction of Ag⁺ is expected to be greatly suppressed. To check this assumption, a Ag-based metal-organic framework containing pyrene, which is in favor of exciton production, is synthesized (denoted as Ag-PTS-BPY) and the structure is solved via single-crystal X-ray diffraction. Ag-PTS-BPY is applied in the photocatalytic selective oxidation of methyl phenyl sulfide, which displays high conversion and selectivity. As expected, no metallic Ag is formed after five cycles of reaction according to the results of X-ray diffraction, Fourier transform infrared, and X-ray photoelectron spectroscopy, and the high conversion is also maintained. The participation of excitons suppresses the involvement of electrons, which are believed to be the reason for the high stability of Ag-PTS-BPY.

Two mixed-ligand coordination polymers based on 2,5-thiophenedicarboxylic acid and flexible N-donor ligands: the protective effect on periodontitis via reducing the release of IL-1β and TNF-α

Two novel mixed-ligand coordination polymers, {[Co(tdc)(btrp)]·0.67DMF}n (1) and {[Zn2(bimb)2(tdc)2]·2H2O}n (2) involving 2,5-thiophenedicarboxylate (H2tdc), and bitopic flexible N-donor ligands, 1,3-bis(1,2,4-triazol-1-yl)propane (btrp) and 1,4-bis((1H-benzo[d]imidazol-1-yl)methyl)benzene (bimb), have been synthesized by the hydrothermal method and characterized via IR, elemental analysis, thermal analysis, and powder X-ray diffraction. The biological functional studies were performed; the treatment activity of the compounds on periodontitis and the specific mechanism was explored. First, the real-time RT-PCR was carried out to determine the inflammatory genes nf-κb and p53 relative expression in periodontal mucosal cells after treating with compounds 1 and 2. Then, the level of the inflammatory cytokine in the gingival crevicular fluid after treating with compounds was also determined by the ELISA detection kit.