Liquid-Like Phase of N,N-Dimethylpyrrolidinium Iodide Impregnated into COFs Endows Fast Lithium Ion Conduction in the Solid State.

A novel kind of solid-state lithium electrolyte was fabricated by impregnating organic ionic plastic crystals (OIPCs) into the pores of covalent organic frameworks (COFs). The liquid-like phase of confined N,N-dimethylpyrrolidinium iodide (P1,1 I) and the ordered nanochannels of COFs simultaneously stimulated the lithium ion conduction.

Effect of steam blanching on peelability and quality of Citrus reticulata Blanco.

Peeling of citrus fruits is the key procedure in the production of citrus products such as canned citrus and citrus vinegar. In order to facilitate this peeling process, Citrus reticulata Blanco is usually heated. The treatments of steam blanching and air cooling were carried out in the citrus peeling experiment. The anatomical details of citrus peel were also observed after steam blanching. The results indicated that the duration of steam blanching had a significant influence on peelability of Citrus reticulata Blanco (P < 0.01). With the proceeding of steam blanching, the maximum stripping force and the maximum stripping length of the citrus peel decreased. Two minutes after steam blanching, parenchyma cell structure and vascular elements were destroyed. The duration of cooling treatment has no significant impact on the peelability of the citrus (P > 0.05). The content of titratable acid, total soluble solid and vitamin C were considerably influenced by steam blanching. When steam blanching duration was within 2 min, the color change ∆Eij was less than 3.0, indicating no significant color change. This study determined 2 min to be the optimal steam blanching duration for achieving the best peelability and quality of peeled citrus, and 5 min or less to be optimal cooling duration. Overall, this study provides a theoretical guideline for the application of the steam blanching treatment in the citrus production.

A BODIPY-carbazole hybrid as a fluorescent probe: the design, synthesis, and discrimination of surfactants and the determination of the CMC values.

Surfactants play important roles in chemical industries and have become well-known environmental pollutants owing to their extensive use in different fields. In this work, we reported a fluorescent probe, namely, BDP-Zn2+ for the discrimination of four kinds of surfactants and the determination of CMC values. BDP-Zn2+ was composed of covalently linked BODIPY, carbazole, N,N-bis(2-pyridylmethyl)ethylenediamine (BPEA) and zinc ions to fabricate a novel push-pull molecular structure. Upon the addition of surfactants, the probe exhibited a turn-on fluorescence response and the emission was enhanced on increasing the surfactant concentrations. This indicated that the fluorescence intensity and the ratios of the emission at 607 nm to that at 514 nm as fingerprints could be used to identify the CMC values of the surfactants. Our current work provides an alternative method to efficiently discriminate different surfactants for the further studies of their physical and chemical functions.

Tetrahydroindazolone substituted 2-aminobenzamides as fluorescent probes: switching metal ion selectivity from zinc to cadmium by interchanging the amino and carbamoyl groups on the fluorophore.

Three fluorescent probes CdABA', CdABA and ZnABA', which are structural isomers of ZnABA, have been designed with N,N-bis(2-pyridylmethyl) ethylenediamine (BPEA) as chelator and 2-aminobenzamide as fluorophore. These probes can be divided into two groups: CdABA, CdABA' for Cd(2+) and ZnABA, ZnABA' for Zn(2+). Although there is little difference in their chemical structures, the two groups of probes exhibit totally different fluorescence properties for preference of Zn(2+) or Cd(2+). In the group of Zn(2+) probes, ZnABA/ZnABA' distinguish Zn(2+) from Cd(2+) with F(Zn)(2+)-F(Cd)(2+) = 1.87-2.00. Upon interchanging the BPEA and carbamoyl groups on the aromatic ring of the fluorophore, the structures of ZnABA/ZnABA' are converted into CdABA/CdABA'. Interestingly, the metal ions selectivity of CdABA/CdABA' was switched to discriminate Cd(2+) from Zn(2+) with F(Cd)(2+)-F(Zn)(2+) = 2.27-2.36, indicating that a small structural modification could lead to a remarkable change of the metal ion selectivity. (1)H NMR titration and ESI mass experiments demonstrated that these fluorescent probers exhibited different coordination modes for Zn(2+) and Cd(2+). With CdABA' as an example, generally, upon addition of Cd(2+), the fluorescence response possesses PET pathway to display no obvious shift of maximum λ(em) in the absence or presence of Cd(2+). However, an ICT pathway could be employed after adding Zn(2+) into the CdABA' solution, resulting in a distinct red-shift of maximal λ(em).

Fast Hydroxide Conduction via Hydrogen-Bonding Network Confined in Benzimidazolium-Functionalized Covalent Organic Frameworks.

In both hydrophobic and hydrophilic nanochannels, confined water clusters spontaneously form dense internal hydrogen bond networks and hence exhibit fast mass-transfer kinetics. Covalent organic frameworks (COFs), a porous polymer, enables one-dimensional open channels to achieve ordered assembly guided by synthetic techniques and allows the accommodation of a large number of water molecules within the nanochannels. In the field of alkaline anion exchange membrane fuel cells, it has been a long-term pursuit of scientists to build abundant hydrogen bonds around hydrogen oxides (OH-) to improve the conduction of OH- by increasing the water content. Here, we designed and synthesized a OH- conductor by assembling benzimidazolium into COFs, and a significantly high conductivity of 10-1 S cm-1 was achieved at 353 K. Theoretical calculations showed that the water clusters confined in the pores of COFs and the regularly arranged hydroxides cooperatively formed a dense hydrogen bond network and OH- conducted diffusive conduction through the Grotthuss hopping of protons in this hydrogen bond network.

A pre-synthetic strategy to construct single ion conductive covalent organic frameworks.

A pre-synthetic strategy was developed for the construction of single ion conductive covalent organic frameworks (COFs). A high Li+ conductivity of 1.6 × 10-3 S cm-1 at 273 K was achieved, and single Na+ and K+ COFs were also obtained by using Na+ and K+ salts as monomers according to this synthetic method.