Room-temperature synthesis of nanometric and luminescent silver-MOFs

Three silver-MOFs were prepared using an optimized, room-temperature methodology starting from AgNO₃ and dicarboxylate ligands in water/ethanol yielding Ag ₂ BDC, Ag ₂ NDC (UAM-1), and Ag ₂ TDC (UAM-2) at 38%-48% (BDC, benzenedicarboxylate; NDC, 1,8-naphthalene-dicarboxylate; TDC, p-terphenyl-4,4″-dicarboxylate). They were characterized by PXRD/FT-IR/TGA/photoluminescence spectroscopy, and the former two by SEM. These materials started decomposing at 330°C, while showing stability. The crystal structure of UAM-1 was determined by PXRD, DFT calculations, and Rietveld refinement. In general, the structure was 3D, with the largest Ag-O bond interlinking 2D layers. The FT-IR spectra revealed 1450 and 1680 bands (cm^-1) of asymmetrically stretching aniso-/iso-bidentate -COO in coordination with 2/3-Ag atoms, accompanied by Ag-O bands at 780-740 cm^-1, all demonstrating the network formation. XRD and SEM showed nanometric-scale crystals in Ag₂BDC, and UAM-1 developed micrometric single-stranded/agglomerated fibrillar particles of varying nanometric widths. Luminescence spectroscopy showed emission by Ag₂BDC, which was attributed to ligand-to-metal or ligand-to-metal-metal transitions, suggesting energy transfer due to the short distance between adjacent BDC molecules. UAM-1 and UAM-2 did not show luminescence emission attributable to ligand-to-metal transition; rather, they presented only UV emission. The stabilities of Ag₂BDC and UAM-1 were evaluated in PBS/DMEM/DMEM+FBS media by XRD, which showed that they lost their crystallinity, resulting in AgCl due to soft-soft (Pearson's principle) affinity.

Luminescent binuclear Zinc(II) organic framework as bifunctional water-stable chemosensor for efficient detection of antibiotics and Cr(VI) anions in water

To achieve the ultrastable LMOFs with predominant luminescent sensing performances, the aromatic π-electron mixed ligands strategy was introduced, and the ternary LMOF of {[Zn₂(HDDB)(bib)_1.5]·3H₂O}_n (1), was fabricated based on 3,5-di(2',4'-dicarboxylphenyl)benozoic acid (H₅DDB) and the N-donor of meta-bis(imidazol-1-yl)benzene (bib) under mixed solvothermal condition. LMOF 1 features the first reported 3D 3,4,4-c {6².8³.10}{6².8}₂{6³.8².10}₂ framework with 21.2 % porosity as well as high thermal and chemical stability. Further luminescent sensing showed that LMOF 1 as a bifunctional chemosensor possessing predominant detectability for sensitive detect the hexavalent chromates and nitroimidazoles/nitrofurans antibiotics in water through strong luminescent quenching effects, with excellent reusability as well as trace detection limits. Moreover, luminescent quenching mechanisms were further investigated from electron transfer and energy transfer viewpoints.

Novel fluorescent lignin-based hydrogel with cellulose nanofibers and carbon dots for highly efficient adsorption and detection of Cr(VI)

A novel fluorescent lignin-based hydrogel with cellulose nanofibers and carbon dots (CDs) was synthesized for the high-value utilization of lignin and control of hexavalent chromium (Cr(VI)). Its chemical and physical structure was characterized, and its Cr(VI) sorption performance was evaluated. The results demonstrated that 3D porous structures were constructed in this hydrogel. The maximum adsorption capacity of this hydrogel was 599.9 mg/g, and its sorption performance met Freundlich and pseudo-second-order models. Meanwhile, this novel hydrogel exhibited high sensitivity to Cr(VI), with a limit of detection of 11.2 mg/L and a wide linear range from 15 to 200 mg/L. Moreover, its mechanism for efficiently adsorbing and detecting Cr(VI) was analyzed. The results confirmed that the efficient adsorption and detection were due to these 3D porous structures generated by the lignin and cellulose nanofibers modified with CDs. The porous structures provided many active sites and ion transport channels, thereby improving the adsorption, and stabilized the fluorescence signal, thus enhancing the detection.

0D/2D Coordination Complexes: Magnetic Studies, Protection, and Mechanism against Ischemic Myocardial Damage by Reducing the Activation of the PI3K/Akt Signaling Pathway

The synthesis of two new coordination compounds was carried out by applying 4-(3-carboxyphenyl)picolinic acid (H₂cppa) as building units under the hydrothermal reaction conditions, whose chemical formulae are [Cu(Hcppa)₂(H₂O)₂]·2H₂O (1) and [Cu(μ₃-cppa)(H₂O)₂] (2). The analysis of structures suggested that 1 featured a discrete molecular structure, which was extended into the three-dimensional supramolecular network with the topology of pcu topology, whereas complex 2 showed a two-dimensional layered network with the fes topology. The magnetic performances of the two synthesized compounds reveal antiferromagnetic coupling between consecutive metal ions. Their application values on ischemic myocardial damage were assessed, and the detailed mechanism of the synthetic complexes was also investigated. The Elabscience Annexin V detection kit was used in this research to determine the percentage of apoptotic cardiomyocytes after different complex treatments. In addition, the relative expression of PI3K/Akt in the myocardium after the application of the compound was determined using the real-time reverse transcription polymerase chain reaction assay.

Four structural diversity MOF-photocatalysts readily prepared for the degradation of the methyl violet dye under UV-visible light

The photocatalytic results demonstrated that all of them displayed efficient photocatalytic performances towards the degradation of methyl violet. The mechanism has been proposed.

Two metal-coordination polymers: Photocatalytic hydrogen production and clinical nursing value on gastric cancer combined with hyperthermic intraperitoneal chemotherapy by inducing induce oxidative stress response

Two new coordination polymers (CPs) of {[Dy₂(abtc)_1.5(H₂O)₃(DMA)]·H₂O·DMA}_n (1; DMA = N,N-dimethylacetamide) and [NH₂(CH₃)₂][Ni_1.5(abtc)]·H₂O (2) were synthesized through utilizing 3,3',5,5'-azobenzenetetracarboxylic acid (H₄abtc) as an organic connector with the solvothermal reaction conditions. The HOMO-LUMO gap for ultra-stable complex 1 is 2.16 eV through the detection of the ultraviolet-visible spectrum with an absorption edge of 570 nm. The complex 1 reveals high catalytic effect for the ultraviolet-visible photocatalytic production of hydrogen, which is due to its light collection of the ligand with dye-like and porous architecture. Furthermore, the promotion effect of compounds 1 and 2 against the gastric cancer treatment was assessed when combined with intraperitoneal hyperthermia. Firstly, the inhibition of compounds 1 and 2 against the invasion and migration of cancer cells was evaluated with transwell assay. Moreover, the genes relative expression levels related with the reactive oxygen species (ROS) production in the cancer cells were also measured with real time reverse transcription-polymerase chain reaction (RT-PCR).

Two cadmium(II) coordination polymers as multi-functional luminescent sensors for the detection of Cr(VI) anions, dichloronitroaniline pesticide, and nitrofuran antibiotic in aqueous media

Two ternary cadmium(II) coordination polymers, with the formulas being {[Cd(tptc)_0.5(bpz)(H₂O)]·0.5H₂O}_n (CP 1), and [Cd(tptc)_0.5(bpy)]_n (CP 2), were designed through mixed ligands strategy. Benefiting from the excellent chemical stability and luminescent property, two Cd(II) CPs possessing efficient multi-functional fluorescent responses toward Cr(VI) anions, 2,6-dichloro-4-nitroaniline pesticide, and nitrofuran antibiotic in aqueous media with high sensitivity, selectivity, and excellent recyclable behaviors with the detection limits (LODs) are 235 ppb for CrO₄^2- anion, 343 ppb for Cr₂O₇^2- anion, 112 ppb for DCN pesticide, 62 ppb for NFT antibiotic for CP 1, and 173 ppb for CrO₄^2- anion, 270 ppb for Cr₂O₇^2- anion, 638 ppb for DCN pesticide, 184 ppb for NFT antibiotic for CP 2, respectively. Besides, the mechanisms of luminescence quenching were revealed from the viewpoint of internal filter effect (IFE) and photoinduced electron transfer (PET).

A twofold interpenetrating two-dimensional zinc(II) coordination polymer: synthesis, crystal structure and physical properties

A novel twofold interpenetrating two-dimensional (2D) Zn^II coordination framework, poly[[(μ-1,3-bis(2-methyl-1H-imidazol-1-yl)benzene-κ²N³:N³)(μ-naphthalene-2,6-dicarboxylato-κ²O²:O⁶)zinc(II)] dimethylformamide monosolvate], {[Zn(C₁₂H₆O₄)(C₁₄H₁₄N₄)]·C₃H₇NO}_n or {[Zn(1,3-BMIB)(NDC)]·DMF}_n (I), where H₂NDC is naphthalene-2,6-dicarboxylic acid, 1,3-BMIB is 1,3-bis(2-methyl-1H-imidazol-1-yl)benzene and DMF is dimethylformamide, was prepared and characterized through IR spectroscopy, elemental analysis, thermal analysis and single-crystal X-ray diffraction. Single-crystal X-ray diffraction analysis revealed that (I) exhibits an unusual twofold interpenetrating 2D network. In addition, it displays strong fluorescence emissions and a high photocatalytic activity for the degradation of Rhodamine B (RhB) under UV-light irradiation.

Three water-stable luminescent two-dimensional CdII-based coordination polymers as sensors for highly sensitive and selective detection of Cr2O72− and CrO42− anions

Three 2D Cd^II-CPs with different topologies were prepared, in which 1 and 3 are rare examples which display excellent sensitivity, selectivity, recyclability and structural stabilities for the detection of Cr₂O₇²⁻/CrO₄²⁻.

A cucurbit[6]uril-based supramolecular assembly as a highly sensitive and quickly responsive luminescent sensor for the detection of fluoroquinolone antibiotics in simulated wastewater

A highly sensitive and quickly responsive CB[6]-based supramolecular assembly was synthesized and used to detect antibiotics through luminescence quenching.