Porous ß-cyclodextrin polymers for rapid and efficient removal of organic micropollutants from water: The role of sulfonation and porosity on adsorption performance.

Removal of organic micropollutants (OMPs) from water, especially hydrophilic and ionized ones, is challenging for water remediation. Herein, porous ß-cyclodextrin polymers (PCPs) with tailored functionalization were prepared based on molecular expansion strategy and sulfonation. Partially benzylated ß-cyclodextrin was knotted by external crosslinker to form PCP1, and knotting PCP1 by expansion molecule generated PCP2. PCP1 and PCP2 were sulfonated to achieve PCP1-SO3H and PCP2-SO3H. Based on systematical adsorption evaluation toward multiple categories of OMPs, it was found that the introduced strong polar -SO3H group could bring strong hydrogen bonding and electrostatic interactions. PCP2 showed the highest surface (998.97 m2/g) displayed more excellent adsorption performance toward neutral and anionic OMPs, and the adsorption mechanism for this property of PCP2 was dominated by hydrophobic interactions. In addition, the PCP1-SO3H with the lowest surface area (39.75 m2/g) rather than PCP2-SO3H with higher surface (519.28 m2/g) exhibited more superior adsorption towards hydrophilic and cationic OMPs, benefiting by hydrogen bonding and electrostatic interactions as well as appropriate porosity. These results not only confirmed the performance enhancement of PCPs through the integration of novel preparation strategy, but also provided fundamental guidance for PCPs design for water remediation.

Photoelectrochemical detection of copper ions based on a covalent organic framework with tunable properties.

Copper ions (Cu2+) play an essential role in various cellular functions, including respiration, nerve conduction, tissue maturation, oxidative stress defense, and iron metabolism. Covalent organic frameworks (COFs) are a class of porous crystalline materials with directed structural designability and high stability due to the combination of different monomers through covalent bonds. In this study, we synthesized a porphyrin-tetrathiazole COF (TT-COF(Zn)) with Zn-porphyrin and tetrathiafulvalene (TTF) as monomers and used it as a photoactive material. The strong light absorption of metalloporphyrin and the electron-rich properties of supplied TTF contribute to its photoelectrochemical performance. Additionally, the sulfur (S) in the TTF can coordinate with Cu2+. Based on these properties, we constructed a highly sensitive photoelectrochemical sensor for detecting Cu2+. The sensor exhibited a linear range from 0.5 nM to 500 nM (R2 = 0.9983) and a detection limit of 0.15 nM for Cu2+. Notably, the sensor performed well when detecting Cu2+ in water samples.

A single-site porphyrin (Cu)-based COF electrocatalyst for the electrochemical detection of gallic acid sensitively.

Sensitive and convenient determination of gallic acid (GA) is vital for food safety. Here, a novel porphyrin (Cu)-based covalent organic framework named as COF(Cu) was successfully synthesized by condensing pre-metalated 5,10,15,20-tetrakis (para-aminophenyl) porphyrin copper (II) and 2,3,6,7-tetra (4-formylphenyl) tetrathiafulvalene ligands. By combining the advantages of porphyrin with tetrathiafulvalene, it may be possible to create a COF with an intrinsically effective charge-transfer channel. In addition, the Cu-N4 type in the COF(Cu) can be regarded as the single-site electrocatalyst. Benefiting from these advantages, the COF(Cu) based electrochemical sensor demonstrated outstanding response to gallic acid (GA). Under the optimal conditions by square wave voltammetry technique, the COF(Cu) modified electrode showed a wide linear range (0.01-1000 µM), a low detection limit (2.81 nM), good reproducibility, acceptable selectivity as well as high stability. Moreover, the established approach was adopted to detect GA in real tea samples with good recoveries, indicating that the COF(Cu) based electrochemical sensor may pave the way for the application in food analysis.

Sulfonated polyhedral oligomeric silsesquioxane-cyclodextrin hybrid polymers for efficient removal of micropollutants from water.

Herein, ß-cyclodextrin-containing hybrid polymers (P1, P2 and P3) were prepared through crosslinking partially benzylated ß-cyclodextrin (PBCD) by octavinylsilsesquioxane (OVS). P1 stood out in screening studies and the residual hydroxyl groups of PBCD was sulfonate-functionalized. The obtained P1-SO3Na showed greatly enhanced adsorption towards cationic MPs and maintained the excellent adsorption performance towards neutral MPs. The rate constants (k2) of cationic MPs upon P1-SO3Na were 9.8-34.8 times larger than those upon P1. The equilibrium uptakes of the neutral and cationic MPs upon P1-SO3Na were above 94.5 %. Meanwhile, P1-SO3Na demonstrated appreciable adsorption capacities, excellent selectivity, effective adsorption of mixed MPs at environmental levels and good reusability. These results confirmed the great potential of P1-SO3Na as effective adsorbent to remove MPs from water.

Synthesis of porous dimethoxypillar[5]arene knitted ß-cyclodextrin copolymers for efficient adsorption of organic micropollutants.

Herein, through knitting benzylated ß-cyclodextrin (BnCD) by dimethoxypillar[5]arene (P[5]), porous copolymers (P[5]-BnCDs) containing two kinds of macrocycles were synthesized with yields not <97 %. The molar ratio of P[5]/BnCD greatly influenced the P[5]-BnCDs' porosity and adsorption performance. When the molar ratio of P[5]/BnCD was 4/1, the P[5]-BnCD (4-1), demonstrated a surface area up to 515.95 m2/g and showed fast adsorption kinetic, high adsorption capacity and good reusability towards the model organic micropollutants (OMPs). The adsorption fitted well with the pseudo-second-order and the Langmuir models, while the thermodynamic studies revealed spontaneous physisorption process. The adsorption mechanism was dominant by host-guest and hydrophobic interactions and the adsorption at environmentally relevant concentrations experiments showed the practicality and superiority in extraction of the OMPs at µg/L level. This study paves a way for the development of versatile porous organic polymers with multiple macrocycles for efficient removal of OMPs from water.

CO2 Photoactivation Study of Adenine Nucleobase: Role of Hydrogen-Bonding Traction.

The discovery and in-depth study of non-biocatalytic applications of active biomolecules are essential for the development of biomimicry. Here, the effect of intermolecular hydrogen-bonding traction on the CO2 photoactivation performance of adenine nucleobase by means of an adenine-containing model system (AMOF-1-4) is uncovered. Remarkably, the hydrogen-bonding schemes around adenines are regularly altered with the increase in the alkyl (methyl, ethyl, isopropyl, and tert-butyl) electron-donating capacity of the coordinated aliphatic carboxylic acids, and thus, lead to a stepwise improvement in CO2 photoreduction activity. Density functional theory calculations demonstrate that strong intermolecular hydrogen-bonding traction surrounding adenine can obviously increase the adenine-CO2 interaction energy and, therefore, result in a smoother CO2 activation process. Significantly, this work also provides new inspiration for expanding the application of adenine to more small-molecule catalytic reactions.

Improved Performance for the Electrochemical Sensing of Acyclovir by Using the rGO-TiO2-Au Nanocomposite-Modified Electrode.

An electrochemical sensor for sensitive sensing of acyclovir (ACV) was designed by using the reduced graphene oxide-TiO2-Au nanocomposite-modified glassy carbon electrode (rGO-TiO2-Au/GCE). Transmission electron microscopy, X-ray diffractometer, and X-ray photoelectron spectroscopy were used to confirm morphology, structure, and composition properties of the rGO-TiO2-Au nanocomposites. Cyclic voltammetry and linear sweep voltammetry were used to demonstrate the analytical performance of the rGO-TiO2-Au/GCE for ACV. As a result, rGO-TiO2-Au/GCE exerted the best response for the oxidation of ACV under the pH of 6.0 PB solution, accumulation time of 80 s at open-circuit, and modifier amount of 7 µl. The oxidation peak currents of ACV increased linearly with its concentration in the range of 1-100 µM, and the detection limit was calculated to be 0.3 µM (S/N = 3). The determination of ACV concentrations in tablet samples also demonstrated satisfactory results.

One-pot green preparation of deep-ultraviolet and dual-emission carbon nanodots for dual-channel ratiometric determination of polyphenol in tea sample.

A novel deep-ultraviolet and dual-emission carbon nanodots (DUCDs)-based dual-channel ratiometric probe was prepared by a one-pot environmental-friendly hydrothermal process using guanidine as the only starting material for sensing polyphenol in tea sample (TPPs). Under the exposure to TPPs, the DUCDs not only provided a characteristic colorimetric response to TPPs, but also displayed TPPs-sensitive ratiometric fluorescence quenching. The detection mechanism was proved to be that enrichment-specific hydroxyl sites (e.g., -NH2 and -COOH) of DUCDs can specifically react with phenolic hydroxyl groups of TPPs to generate dynamic amide and carboxylate bonds by dehydration and/or condensation reaction. As a result, a new carbon nanomaterial with decrement of surface passivation groups, inherent light-absorbing, and invalid fluorescence emission was generated. The ratio (FL297nm/FL395nm) of fluorescence intensity at 297 nm and 395 nm of DUCDs excited at 275 nm decreased with increasing TPPs concentration. The linearity range was 5.0 ng/mL to 100 µg/mL with a detection limit (DL) of 3.5 ± 0.04 ng/mL for TPPs (n = 3, 3σ/k). Colorimetry of DUCDs, best measured as absorbance at 320 nm, was increased linearly in the TPP concentration range 200 ng/mL-200 µg/mL with a DL of 94.7 ± 0.04 ng/mL (n = 3, 3σ/k). The probe was successfully applied to the determination of TPPs in real tea samples, showing potential application prospects in food analysis.

Stepped Channels Integrated Lithium-Sulfur Separator via Photoinduced Multidimensional Fabrication of Metal-Organic Frameworks.

Multidimensional fabrication of metal-organic frameworks (MOFs) into multilevel channel integrated devices are in high demanded for Li-S separators. Such separators have advantages in pore-engineering that might fulfill requirements such as intercepting the diffusing polysulfides and improving the Li+ /electrolyte transfer in Li-S batteries. However, most reported works focus on the roles of MOFs as ionic sieves for polysulfides while offering limited investigation on the tuning of Li+ transfer across the separators. A photoinduced heat-assisted processing strategy is proposed to fabricate MOFs into multidimensional devices (e.g., hollow/Janus fibers, double-or triple-layer membranes). For the first time, a triple-layer separator with stepped-channels has been designed and demonstrated as a powerful separator with outstanding specific capacity (1365.0 mAh g-1 ) and cycling performance (0.03 % fading per cycle from 100th to 700th cycle), which is superior to single/double-layer and commercial separators. The findings may expedite the development of MOF-based membranes and extend the scope of MOFs in energy-storage technologies.

Multifunctional luminescent Zn(ii)-based metal-organic framework for high proton-conductivity and detection of Cr3+ ions in the presence of mixed metal ions.

A luminescent MOF with rectangular channels was synthesized and characterized. It is capable of showing a high proton conductivity up to 0.95 × 10-2 S cm-1 at 60 °C and 97% RH, and sensing metal ions (particularly Cr3+ ions), through fluorescence quenching in presence of mixed metal ions.

Changes in Cognitive Function in Patients with Primary Insomnia.

BACKGROUND: Neuropsychological evidence is not sufficient concerning whether there is cognitive impairment in patients with primary insomnia. Further study is needed in this regard. AIMS: To measure the changes in cognitive functioning in patients with primary insomnia. METHODS: 40 patients with insomnia (insomnia group) and 48 normal sleepers (control group) were tested using the Pittsburgh Sleep Quality Index (PSQI), episodic memory test, and Montreal Cognitive Assessment (MoCA). RESULTS: The insomnia group had significantly lower scores than the control group in the naming (t=3.17, p=0.002), immediate memory (t=3.33, p=0.001), and delayed recall (t=6.05, p=0.001) sections of the MoCA, as well as a lower overall score on the MoCA (t=3.24, p=0.002). Participants with different degrees of insomnia also had significantly different scores in naming (F=7.56, p=0.001), language (F=3.22, p=0.045), total score (F=6.72, p=0.002), delayed memory (F=8.41, p=0.001), and delayed recall (F=22.67, p=0.001) sections of the MoCA. The age of primary insomnia patients was correlated to MoCA total score, immediate memory, delayed recall, and delayed recognition function, also with statistical significance. The years of education of primary insomnia patients was also significantly correlated to overall MoCA score, as well as visuospatial and executive function, naming, attention, language, and abstraction sections of the MoCA. CONCLUSION: Primary insomnia patients have cognitive impairment. The more severe the insomnia is, the wider the range of and the more serious the degree of cognitive impairment is.

Coordination and supramolecular assembly of {Cd2Ge8V12O48} building block and cucurbit[6] to form rotaxane-shaped hybrids.

Assembly of cucurbit[6] and a {Cd2Ge8V12O48} cluster produced two rotaxane-shaped and polyrotaxane-shaped solids by changing the ratio of starting precursors in the system. The high oxygen density of the polyoxoanion surface provides active sites to extend a single rotaxane-shaped hybrid 1 to a 1D polyrotaxane-shaped hybrid 2. This construction strategy may afford an entirely new methodology for polyoxometalate-based hybrid chemistry.

Oxidation of SCN- with air and micellar polyoxoperoxometalates.

The nanocatalysts were fabricated by reacting amphiphilic quaternary ammoniums with polyoxoperoxometalates (POPMs) K(n)[PW(12-)(x)Ti(x)O(40-)(x)(O(2))(x)](x=1, 2 and 3; n=5, 7 and 9). Fourier transform infrared spectroscopy (IR), transmission electron microscopy (TEM), and UV-vis-NIR spectrophotometer were used to characterize the resulting samples. This kind of nanocatalysts could provide a kind of nanoreactors to promote the degradation of NH(4)SCN into simple inorganic compounds such as SO(4)(2-), HCO(3)(-) and NO(3)(-) using oxygen as an oxidant under room conditions. The leaching test showed that the POPMs micellar catalyst had excellent stability and could be used as a heterogeneous one at least five times.